Code

Fix regression in handling of data for non-UTF-8 locales
[tig.git] / tig.c
diff --git a/tig.c b/tig.c
index 8e06c1ac5031bbb19cb3e0275e91e46c71652976..b16fe244d0fd2d9b26d4208fd99c9ffaecf4b338 100644 (file)
--- a/tig.c
+++ b/tig.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2006-2008 Jonas Fonseca <fonseca@diku.dk>
+/* Copyright (c) 2006-2009 Jonas Fonseca <fonseca@diku.dk>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <sys/stat.h>
+#include <sys/select.h>
 #include <unistd.h>
 #include <time.h>
+#include <fcntl.h>
 
 #include <regex.h>
 
 static void __NORETURN die(const char *err, ...);
 static void warn(const char *msg, ...);
 static void report(const char *msg, ...);
-static int read_properties(FILE *pipe, const char *separators, int (*read)(char *, size_t, char *, size_t));
 static void set_nonblocking_input(bool loading);
 static size_t utf8_length(const char *string, int *width, size_t max_width, int *trimmed, bool reserve);
+static bool prompt_yesno(const char *prompt);
+static int load_refs(void);
 
 #define ABS(x)         ((x) >= 0  ? (x) : -(x))
 #define MIN(x, y)      ((x) < (y) ? (x) :  (y))
@@ -76,7 +80,8 @@ static size_t utf8_length(const char *string, int *width, size_t max_width, int
 
 #define SIZEOF_STR     1024    /* Default string size. */
 #define SIZEOF_REF     256     /* Size of symbolic or SHA1 ID. */
-#define SIZEOF_REV     41      /* Holds a SHA-1 and an ending NUL */
+#define SIZEOF_REV     41      /* Holds a SHA-1 and an ending NUL. */
+#define SIZEOF_ARG     32      /* Default argument array size. */
 
 /* Revision graph */
 
@@ -113,34 +118,9 @@ static size_t utf8_length(const char *string, int *width, size_t max_width, int
 #define NULL_ID                "0000000000000000000000000000000000000000"
 
 #ifndef GIT_CONFIG
-#define GIT_CONFIG "git config"
+#define GIT_CONFIG "config"
 #endif
 
-#define TIG_LS_REMOTE \
-       "git ls-remote . 2>/dev/null"
-
-#define TIG_DIFF_CMD \
-       "git show --pretty=fuller --no-color --root --patch-with-stat --find-copies-harder -C %s 2>/dev/null"
-
-#define TIG_LOG_CMD    \
-       "git log --no-color --cc --stat -n100 %s 2>/dev/null"
-
-#define TIG_MAIN_CMD \
-       "git log --no-color --topo-order --parents --boundary --pretty=raw %s 2>/dev/null"
-
-#define TIG_TREE_CMD   \
-       "git ls-tree %s %s"
-
-#define TIG_BLOB_CMD   \
-       "git cat-file blob %s"
-
-/* XXX: Needs to be defined to the empty string. */
-#define TIG_HELP_CMD   ""
-#define TIG_PAGER_CMD  ""
-#define TIG_STATUS_CMD ""
-#define TIG_STAGE_CMD  ""
-#define TIG_BLAME_CMD  ""
-
 /* Some ascii-shorthands fitted into the ncurses namespace. */
 #define KEY_TAB                '\t'
 #define KEY_RETURN     '\r'
@@ -158,7 +138,15 @@ struct ref {
        unsigned int next:1;    /* For ref lists: are there more refs? */
 };
 
-static struct ref **get_refs(char *id);
+static struct ref **get_refs(const char *id);
+
+enum format_flags {
+       FORMAT_ALL,             /* Perform replacement in all arguments. */
+       FORMAT_DASH,            /* Perform replacement up until "--". */
+       FORMAT_NONE             /* No replacement should be performed. */
+};
+
+static bool format_argv(const char *dst[], const char *src[], enum format_flags flags);
 
 struct int_map {
        const char *name;
@@ -271,49 +259,373 @@ string_enum_compare(const char *str1, const char *str2, int len)
        return 0;
 }
 
-/* Shell quoting
- *
- * NOTE: The following is a slightly modified copy of the git project's shell
- * quoting routines found in the quote.c file.
- *
- * Help to copy the thing properly quoted for the shell safety.  any single
- * quote is replaced with '\'', any exclamation point is replaced with '\!',
- * and the whole thing is enclosed in a
- *
- * E.g.
- *  original     sq_quote     result
- *  name     ==> name      ==> 'name'
- *  a b      ==> a b       ==> 'a b'
- *  a'b      ==> a'\''b    ==> 'a'\''b'
- *  a!b      ==> a'\!'b    ==> 'a'\!'b'
+#define prefixcmp(str1, str2) \
+       strncmp(str1, str2, STRING_SIZE(str2))
+
+static inline int
+suffixcmp(const char *str, int slen, const char *suffix)
+{
+       size_t len = slen >= 0 ? slen : strlen(str);
+       size_t suffixlen = strlen(suffix);
+
+       return suffixlen < len ? strcmp(str + len - suffixlen, suffix) : -1;
+}
+
+
+static bool
+argv_from_string(const char *argv[SIZEOF_ARG], int *argc, char *cmd)
+{
+       int valuelen;
+
+       while (*cmd && *argc < SIZEOF_ARG && (valuelen = strcspn(cmd, " \t"))) {
+               bool advance = cmd[valuelen] != 0;
+
+               cmd[valuelen] = 0;
+               argv[(*argc)++] = chomp_string(cmd);
+               cmd += valuelen + advance;
+       }
+
+       if (*argc < SIZEOF_ARG)
+               argv[*argc] = NULL;
+       return *argc < SIZEOF_ARG;
+}
+
+static void
+argv_from_env(const char **argv, const char *name)
+{
+       char *env = argv ? getenv(name) : NULL;
+       int argc = 0;
+
+       if (env && *env)
+               env = strdup(env);
+       if (env && !argv_from_string(argv, &argc, env))
+               die("Too many arguments in the `%s` environment variable", name);
+}
+
+
+/*
+ * Executing external commands.
  */
 
-static size_t
-sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
+enum io_type {
+       IO_FD,                  /* File descriptor based IO. */
+       IO_BG,                  /* Execute command in the background. */
+       IO_FG,                  /* Execute command with same std{in,out,err}. */
+       IO_RD,                  /* Read only fork+exec IO. */
+       IO_WR,                  /* Write only fork+exec IO. */
+};
+
+struct io {
+       enum io_type type;      /* The requested type of pipe. */
+       const char *dir;        /* Directory from which to execute. */
+       pid_t pid;              /* Pipe for reading or writing. */
+       int pipe;               /* Pipe end for reading or writing. */
+       int error;              /* Error status. */
+       const char *argv[SIZEOF_ARG];   /* Shell command arguments. */
+       char *buf;              /* Read buffer. */
+       size_t bufalloc;        /* Allocated buffer size. */
+       size_t bufsize;         /* Buffer content size. */
+       char *bufpos;           /* Current buffer position. */
+       unsigned int eof:1;     /* Has end of file been reached. */
+};
+
+static void
+reset_io(struct io *io)
 {
-       char c;
+       io->pipe = -1;
+       io->pid = 0;
+       io->buf = io->bufpos = NULL;
+       io->bufalloc = io->bufsize = 0;
+       io->error = 0;
+       io->eof = 0;
+}
 
-#define BUFPUT(x) do { if (bufsize < SIZEOF_STR) buf[bufsize++] = (x); } while (0)
+static void
+init_io(struct io *io, const char *dir, enum io_type type)
+{
+       reset_io(io);
+       io->type = type;
+       io->dir = dir;
+}
 
-       BUFPUT('\'');
-       while ((c = *src++)) {
-               if (c == '\'' || c == '!') {
-                       BUFPUT('\'');
-                       BUFPUT('\\');
-                       BUFPUT(c);
-                       BUFPUT('\'');
-               } else {
-                       BUFPUT(c);
+static bool
+init_io_rd(struct io *io, const char *argv[], const char *dir,
+               enum format_flags flags)
+{
+       init_io(io, dir, IO_RD);
+       return format_argv(io->argv, argv, flags);
+}
+
+static bool
+io_open(struct io *io, const char *name)
+{
+       init_io(io, NULL, IO_FD);
+       io->pipe = *name ? open(name, O_RDONLY) : STDIN_FILENO;
+       return io->pipe != -1;
+}
+
+static bool
+kill_io(struct io *io)
+{
+       return kill(io->pid, SIGKILL) != -1;
+}
+
+static bool
+done_io(struct io *io)
+{
+       pid_t pid = io->pid;
+
+       if (io->pipe != -1)
+               close(io->pipe);
+       free(io->buf);
+       reset_io(io);
+
+       while (pid > 0) {
+               int status;
+               pid_t waiting = waitpid(pid, &status, 0);
+
+               if (waiting < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       report("waitpid failed (%s)", strerror(errno));
+                       return FALSE;
+               }
+
+               return waiting == pid &&
+                      !WIFSIGNALED(status) &&
+                      WIFEXITED(status) &&
+                      !WEXITSTATUS(status);
+       }
+
+       return TRUE;
+}
+
+static bool
+start_io(struct io *io)
+{
+       int pipefds[2] = { -1, -1 };
+
+       if (io->type == IO_FD)
+               return TRUE;
+
+       if ((io->type == IO_RD || io->type == IO_WR) &&
+           pipe(pipefds) < 0)
+               return FALSE;
+
+       if ((io->pid = fork())) {
+               if (pipefds[!(io->type == IO_WR)] != -1)
+                       close(pipefds[!(io->type == IO_WR)]);
+               if (io->pid != -1) {
+                       io->pipe = pipefds[!!(io->type == IO_WR)];
+                       return TRUE;
+               }
+
+       } else {
+               if (io->type != IO_FG) {
+                       int devnull = open("/dev/null", O_RDWR);
+                       int readfd  = io->type == IO_WR ? pipefds[0] : devnull;
+                       int writefd = io->type == IO_RD ? pipefds[1] : devnull;
+
+                       dup2(readfd,  STDIN_FILENO);
+                       dup2(writefd, STDOUT_FILENO);
+                       dup2(devnull, STDERR_FILENO);
+
+                       close(devnull);
+                       if (pipefds[0] != -1)
+                               close(pipefds[0]);
+                       if (pipefds[1] != -1)
+                               close(pipefds[1]);
+               }
+
+               if (io->dir && *io->dir && chdir(io->dir) == -1)
+                       die("Failed to change directory: %s", strerror(errno));
+
+               execvp(io->argv[0], (char *const*) io->argv);
+               die("Failed to execute program: %s", strerror(errno));
+       }
+
+       if (pipefds[!!(io->type == IO_WR)] != -1)
+               close(pipefds[!!(io->type == IO_WR)]);
+       return FALSE;
+}
+
+static bool
+run_io(struct io *io, const char **argv, const char *dir, enum io_type type)
+{
+       init_io(io, dir, type);
+       if (!format_argv(io->argv, argv, FORMAT_NONE))
+               return FALSE;
+       return start_io(io);
+}
+
+static int
+run_io_do(struct io *io)
+{
+       return start_io(io) && done_io(io);
+}
+
+static int
+run_io_bg(const char **argv)
+{
+       struct io io = {};
+
+       init_io(&io, NULL, IO_BG);
+       if (!format_argv(io.argv, argv, FORMAT_NONE))
+               return FALSE;
+       return run_io_do(&io);
+}
+
+static bool
+run_io_fg(const char **argv, const char *dir)
+{
+       struct io io = {};
+
+       init_io(&io, dir, IO_FG);
+       if (!format_argv(io.argv, argv, FORMAT_NONE))
+               return FALSE;
+       return run_io_do(&io);
+}
+
+static bool
+run_io_rd(struct io *io, const char **argv, enum format_flags flags)
+{
+       return init_io_rd(io, argv, NULL, flags) && start_io(io);
+}
+
+static bool
+io_eof(struct io *io)
+{
+       return io->eof;
+}
+
+static int
+io_error(struct io *io)
+{
+       return io->error;
+}
+
+static bool
+io_strerror(struct io *io)
+{
+       return strerror(io->error);
+}
+
+static bool
+io_can_read(struct io *io)
+{
+       struct timeval tv = { 0, 500 };
+       fd_set fds;
+
+       FD_ZERO(&fds);
+       FD_SET(io->pipe, &fds);
+
+       return select(io->pipe + 1, &fds, NULL, NULL, &tv) > 0;
+}
+
+static ssize_t
+io_read(struct io *io, void *buf, size_t bufsize)
+{
+       do {
+               ssize_t readsize = read(io->pipe, buf, bufsize);
+
+               if (readsize < 0 && (errno == EAGAIN || errno == EINTR))
+                       continue;
+               else if (readsize == -1)
+                       io->error = errno;
+               else if (readsize == 0)
+                       io->eof = 1;
+               return readsize;
+       } while (1);
+}
+
+static char *
+io_get(struct io *io, int c, bool can_read)
+{
+       char *eol;
+       ssize_t readsize;
+
+       if (!io->buf) {
+               io->buf = io->bufpos = malloc(BUFSIZ);
+               if (!io->buf)
+                       return NULL;
+               io->bufalloc = BUFSIZ;
+               io->bufsize = 0;
+       }
+
+       while (TRUE) {
+               if (io->bufsize > 0) {
+                       eol = memchr(io->bufpos, c, io->bufsize);
+                       if (eol) {
+                               char *line = io->bufpos;
+
+                               *eol = 0;
+                               io->bufpos = eol + 1;
+                               io->bufsize -= io->bufpos - line;
+                               return line;
+                       }
+               }
+
+               if (io_eof(io)) {
+                       if (io->bufsize) {
+                               io->bufpos[io->bufsize] = 0;
+                               io->bufsize = 0;
+                               return io->bufpos;
+                       }
+                       return NULL;
                }
+
+               if (!can_read)
+                       return NULL;
+
+               if (io->bufsize > 0 && io->bufpos > io->buf)
+                       memmove(io->buf, io->bufpos, io->bufsize);
+
+               io->bufpos = io->buf;
+               readsize = io_read(io, io->buf + io->bufsize, io->bufalloc - io->bufsize);
+               if (io_error(io))
+                       return NULL;
+               io->bufsize += readsize;
+       }
+}
+
+static bool
+io_write(struct io *io, const void *buf, size_t bufsize)
+{
+       size_t written = 0;
+
+       while (!io_error(io) && written < bufsize) {
+               ssize_t size;
+
+               size = write(io->pipe, buf + written, bufsize - written);
+               if (size < 0 && (errno == EAGAIN || errno == EINTR))
+                       continue;
+               else if (size == -1)
+                       io->error = errno;
+               else
+                       written += size;
        }
-       BUFPUT('\'');
 
-       if (bufsize < SIZEOF_STR)
-               buf[bufsize] = 0;
+       return written == bufsize;
+}
+
+static bool
+run_io_buf(const char **argv, char buf[], size_t bufsize)
+{
+       struct io io = {};
+       bool error;
+
+       if (!run_io_rd(&io, argv, FORMAT_NONE))
+               return FALSE;
+
+       io.buf = io.bufpos = buf;
+       io.bufalloc = bufsize;
+       error = !io_get(&io, '\n', TRUE) && io_error(&io);
+       io.buf = NULL;
 
-       return bufsize;
+       return done_io(&io) || error;
 }
 
+static int read_properties(struct io *io, const char *separators, int (*read)(char *, size_t, char *, size_t));
 
 /*
  * User requests
@@ -343,6 +655,13 @@ sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
        REQ_(VIEW_CLOSE,        "Close the current view"), \
        REQ_(QUIT,              "Close all views and quit"), \
        \
+       REQ_GROUP("View specific requests") \
+       REQ_(STATUS_UPDATE,     "Update file status"), \
+       REQ_(STATUS_REVERT,     "Revert file changes"), \
+       REQ_(STATUS_MERGE,      "Merge file using external tool"), \
+       REQ_(STAGE_NEXT,        "Find next chunk to stage"), \
+       REQ_(TREE_PARENT,       "Switch to parent directory in tree view"), \
+       \
        REQ_GROUP("Cursor navigation") \
        REQ_(MOVE_UP,           "Move cursor one line up"), \
        REQ_(MOVE_DOWN,         "Move cursor one line down"), \
@@ -363,20 +682,19 @@ sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
        REQ_(FIND_NEXT,         "Find next search match"), \
        REQ_(FIND_PREV,         "Find previous search match"), \
        \
+       REQ_GROUP("Option manipulation") \
+       REQ_(TOGGLE_LINENO,     "Toggle line numbers"), \
+       REQ_(TOGGLE_DATE,       "Toggle date display"), \
+       REQ_(TOGGLE_AUTHOR,     "Toggle author display"), \
+       REQ_(TOGGLE_REV_GRAPH,  "Toggle revision graph visualization"), \
+       REQ_(TOGGLE_REFS,       "Toggle reference display (tags/branches)"), \
+       \
        REQ_GROUP("Misc") \
        REQ_(PROMPT,            "Bring up the prompt"), \
        REQ_(SCREEN_REDRAW,     "Redraw the screen"), \
        REQ_(SCREEN_RESIZE,     "Resize the screen"), \
        REQ_(SHOW_VERSION,      "Show version information"), \
        REQ_(STOP_LOADING,      "Stop all loading views"), \
-       REQ_(TOGGLE_LINENO,     "Toggle line numbers"), \
-       REQ_(TOGGLE_DATE,       "Toggle date display"), \
-       REQ_(TOGGLE_AUTHOR,     "Toggle author display"), \
-       REQ_(TOGGLE_REV_GRAPH,  "Toggle revision graph visualization"), \
-       REQ_(TOGGLE_REFS,       "Toggle reference display (tags/branches)"), \
-       REQ_(STATUS_UPDATE,     "Update file status"), \
-       REQ_(STATUS_MERGE,      "Merge file using external tool"), \
-       REQ_(TREE_PARENT,       "Switch to parent directory in tree view"), \
        REQ_(EDIT,              "Open in editor"), \
        REQ_(NONE,              "Do nothing")
 
@@ -396,9 +714,9 @@ enum request {
 
 struct request_info {
        enum request request;
-       char *name;
+       const char *name;
        int namelen;
-       char *help;
+       const char *help;
 };
 
 static struct request_info req_info[] = {
@@ -450,15 +768,13 @@ static bool opt_rev_graph         = FALSE;
 static bool opt_show_refs              = TRUE;
 static int opt_num_interval            = NUMBER_INTERVAL;
 static int opt_tab_size                        = TAB_SIZE;
-static enum request opt_request                = REQ_VIEW_MAIN;
-static char opt_cmd[SIZEOF_STR]                = "";
+static int opt_author_cols             = AUTHOR_COLS-1;
 static char opt_path[SIZEOF_STR]       = "";
 static char opt_file[SIZEOF_STR]       = "";
 static char opt_ref[SIZEOF_REF]                = "";
 static char opt_head[SIZEOF_REF]       = "";
+static char opt_head_rev[SIZEOF_REV]   = "";
 static char opt_remote[SIZEOF_REF]     = "";
-static bool opt_no_head                        = TRUE;
-static FILE *opt_pipe                  = NULL;
 static char opt_encoding[20]           = "UTF-8";
 static bool opt_utf8                   = TRUE;
 static char opt_codeset[20]            = "UTF-8";
@@ -468,35 +784,40 @@ static char opt_cdup[SIZEOF_STR]  = "";
 static char opt_git_dir[SIZEOF_STR]    = "";
 static signed char opt_is_inside_work_tree     = -1; /* set to TRUE or FALSE */
 static char opt_editor[SIZEOF_STR]     = "";
+static FILE *opt_tty                   = NULL;
 
-static bool
-parse_options(int argc, char *argv[])
+#define is_initial_commit()    (!*opt_head_rev)
+#define is_head_commit(rev)    (!strcmp((rev), "HEAD") || !strcmp(opt_head_rev, (rev)))
+
+static enum request
+parse_options(int argc, const char *argv[], const char ***run_argv)
 {
-       size_t buf_size;
-       char *subcommand;
+       enum request request = REQ_VIEW_MAIN;
+       const char *subcommand;
        bool seen_dashdash = FALSE;
-       int i;
+       /* XXX: This is vulnerable to the user overriding options
+        * required for the main view parser. */
+       static const char *custom_argv[SIZEOF_ARG] = {
+               "git", "log", "--no-color", "--pretty=raw", "--parents",
+                       "--topo-order", NULL
+       };
+       int i, j = 6;
 
-       if (!isatty(STDIN_FILENO)) {
-               opt_request = REQ_VIEW_PAGER;
-               opt_pipe = stdin;
-               return TRUE;
-       }
+       if (!isatty(STDIN_FILENO))
+               return REQ_VIEW_PAGER;
 
        if (argc <= 1)
-               return TRUE;
+               return REQ_VIEW_MAIN;
 
        subcommand = argv[1];
        if (!strcmp(subcommand, "status") || !strcmp(subcommand, "-S")) {
-               opt_request = REQ_VIEW_STATUS;
                if (!strcmp(subcommand, "-S"))
                        warn("`-S' has been deprecated; use `tig status' instead");
                if (argc > 2)
                        warn("ignoring arguments after `%s'", subcommand);
-               return TRUE;
+               return REQ_VIEW_STATUS;
 
        } else if (!strcmp(subcommand, "blame")) {
-               opt_request = REQ_VIEW_BLAME;
                if (argc <= 2 || argc > 4)
                        die("invalid number of options to blame\n\n%s", usage);
 
@@ -507,53 +828,48 @@ parse_options(int argc, char *argv[])
                }
 
                string_ncopy(opt_file, argv[i], strlen(argv[i]));
-               return TRUE;
+               return REQ_VIEW_BLAME;
 
        } else if (!strcmp(subcommand, "show")) {
-               opt_request = REQ_VIEW_DIFF;
+               request = REQ_VIEW_DIFF;
 
        } else if (!strcmp(subcommand, "log") || !strcmp(subcommand, "diff")) {
-               opt_request = subcommand[0] == 'l'
-                           ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
+               request = subcommand[0] == 'l' ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
                warn("`tig %s' has been deprecated", subcommand);
 
        } else {
                subcommand = NULL;
        }
 
-       if (!subcommand)
-               /* XXX: This is vulnerable to the user overriding
-                * options required for the main view parser. */
-               string_copy(opt_cmd, "git log --no-color --pretty=raw --boundary --parents");
-       else
-               string_format(opt_cmd, "git %s", subcommand);
-
-       buf_size = strlen(opt_cmd);
+       if (subcommand) {
+               custom_argv[1] = subcommand;
+               j = 2;
+       }
 
        for (i = 1 + !!subcommand; i < argc; i++) {
-               char *opt = argv[i];
+               const char *opt = argv[i];
 
                if (seen_dashdash || !strcmp(opt, "--")) {
                        seen_dashdash = TRUE;
 
                } else if (!strcmp(opt, "-v") || !strcmp(opt, "--version")) {
                        printf("tig version %s\n", TIG_VERSION);
-                       return FALSE;
+                       return REQ_NONE;
 
                } else if (!strcmp(opt, "-h") || !strcmp(opt, "--help")) {
                        printf("%s\n", usage);
-                       return FALSE;
+                       return REQ_NONE;
                }
 
-               opt_cmd[buf_size++] = ' ';
-               buf_size = sq_quote(opt_cmd, buf_size, opt);
-               if (buf_size >= sizeof(opt_cmd))
+               custom_argv[j++] = opt;
+               if (j >= ARRAY_SIZE(custom_argv))
                        die("command too long");
        }
 
-       opt_cmd[buf_size] = 0;
+       custom_argv[j] = NULL;
+       *run_argv = custom_argv;
 
-       return TRUE;
+       return request;
 }
 
 
@@ -641,7 +957,7 @@ static struct line_info line_info[] = {
 };
 
 static enum line_type
-get_line_type(char *line)
+get_line_type(const char *line)
 {
        int linelen = strlen(line);
        enum line_type type;
@@ -663,7 +979,7 @@ get_line_attr(enum line_type type)
 }
 
 static struct line_info *
-get_line_info(char *name)
+get_line_info(const char *name)
 {
        size_t namelen = strlen(name);
        enum line_type type;
@@ -705,6 +1021,7 @@ struct line {
        /* State flags */
        unsigned int selected:1;
        unsigned int dirty:1;
+       unsigned int cleareol:1;
 
        void *data;             /* User data */
 };
@@ -717,7 +1034,6 @@ struct line {
 struct keybinding {
        int alias;
        enum request request;
-       struct keybinding *next;
 };
 
 static struct keybinding default_keybindings[] = {
@@ -778,7 +1094,9 @@ static struct keybinding default_keybindings[] = {
        { 'F',          REQ_TOGGLE_REFS },
        { ':',          REQ_PROMPT },
        { 'u',          REQ_STATUS_UPDATE },
+       { '!',          REQ_STATUS_REVERT },
        { 'M',          REQ_STATUS_MERGE },
+       { '@',          REQ_STAGE_NEXT },
        { ',',          REQ_TREE_PARENT },
        { 'e',          REQ_EDIT },
 
@@ -814,21 +1132,23 @@ static struct int_map keymap_table[] = {
 #define set_keymap(map, name) \
        set_from_int_map(keymap_table, ARRAY_SIZE(keymap_table), map, name, strlen(name))
 
-static struct keybinding *keybindings[ARRAY_SIZE(keymap_table)];
+struct keybinding_table {
+       struct keybinding *data;
+       size_t size;
+};
+
+static struct keybinding_table keybindings[ARRAY_SIZE(keymap_table)];
 
 static void
 add_keybinding(enum keymap keymap, enum request request, int key)
 {
-       struct keybinding *keybinding;
+       struct keybinding_table *table = &keybindings[keymap];
 
-       keybinding = calloc(1, sizeof(*keybinding));
-       if (!keybinding)
+       table->data = realloc(table->data, (table->size + 1) * sizeof(*table->data));
+       if (!table->data)
                die("Failed to allocate keybinding");
-
-       keybinding->alias = key;
-       keybinding->request = request;
-       keybinding->next = keybindings[keymap];
-       keybindings[keymap] = keybinding;
+       table->data[table->size].alias = key;
+       table->data[table->size++].request = request;
 }
 
 /* Looks for a key binding first in the given map, then in the generic map, and
@@ -836,16 +1156,15 @@ add_keybinding(enum keymap keymap, enum request request, int key)
 static enum request
 get_keybinding(enum keymap keymap, int key)
 {
-       struct keybinding *kbd;
-       int i;
+       size_t i;
 
-       for (kbd = keybindings[keymap]; kbd; kbd = kbd->next)
-               if (kbd->alias == key)
-                       return kbd->request;
+       for (i = 0; i < keybindings[keymap].size; i++)
+               if (keybindings[keymap].data[i].alias == key)
+                       return keybindings[keymap].data[i].request;
 
-       for (kbd = keybindings[KEYMAP_GENERIC]; kbd; kbd = kbd->next)
-               if (kbd->alias == key)
-                       return kbd->request;
+       for (i = 0; i < keybindings[KEYMAP_GENERIC].size; i++)
+               if (keybindings[KEYMAP_GENERIC].data[i].alias == key)
+                       return keybindings[KEYMAP_GENERIC].data[i].request;
 
        for (i = 0; i < ARRAY_SIZE(default_keybindings); i++)
                if (default_keybindings[i].alias == key)
@@ -856,7 +1175,7 @@ get_keybinding(enum keymap keymap, int key)
 
 
 struct key {
-       char *name;
+       const char *name;
        int value;
 };
 
@@ -906,11 +1225,11 @@ get_key_value(const char *name)
        return ERR;
 }
 
-static char *
+static const char *
 get_key_name(int key_value)
 {
        static char key_char[] = "'X'";
-       char *seq = NULL;
+       const char *seq = NULL;
        int key;
 
        for (key = 0; key < ARRAY_SIZE(key_table); key++)
@@ -924,10 +1243,10 @@ get_key_name(int key_value)
                seq = key_char;
        }
 
-       return seq ? seq : "'?'";
+       return seq ? seq : "(no key)";
 }
 
-static char *
+static const char *
 get_key(enum request request)
 {
        static char buf[BUFSIZ];
@@ -955,34 +1274,34 @@ get_key(enum request request)
 struct run_request {
        enum keymap keymap;
        int key;
-       char cmd[SIZEOF_STR];
+       const char *argv[SIZEOF_ARG];
 };
 
 static struct run_request *run_request;
 static size_t run_requests;
 
 static enum request
-add_run_request(enum keymap keymap, int key, int argc, char **argv)
+add_run_request(enum keymap keymap, int key, int argc, const char **argv)
 {
        struct run_request *req;
-       char cmd[SIZEOF_STR];
-       size_t bufpos;
 
-       for (bufpos = 0; argc > 0; argc--, argv++)
-               if (!string_format_from(cmd, &bufpos, "%s ", *argv))
-                       return REQ_NONE;
+       if (argc >= ARRAY_SIZE(req->argv) - 1)
+               return REQ_NONE;
 
        req = realloc(run_request, (run_requests + 1) * sizeof(*run_request));
        if (!req)
                return REQ_NONE;
 
        run_request = req;
-       req = &run_request[run_requests++];
-       string_copy(req->cmd, cmd);
+       req = &run_request[run_requests];
        req->keymap = keymap;
        req->key = key;
+       req->argv[0] = NULL;
+
+       if (!format_argv(req->argv, argv, FORMAT_NONE))
+               return REQ_NONE;
 
-       return REQ_NONE + run_requests;
+       return REQ_NONE + ++run_requests;
 }
 
 static struct run_request *
@@ -996,20 +1315,23 @@ get_run_request(enum request request)
 static void
 add_builtin_run_requests(void)
 {
+       const char *cherry_pick[] = { "git", "cherry-pick", "%(commit)", NULL };
+       const char *gc[] = { "git", "gc", NULL };
        struct {
                enum keymap keymap;
                int key;
-               char *argv[1];
+               int argc;
+               const char **argv;
        } reqs[] = {
-               { KEYMAP_MAIN,    'C', { "git cherry-pick %(commit)" } },
-               { KEYMAP_GENERIC, 'G', { "git gc" } },
+               { KEYMAP_MAIN,    'C', ARRAY_SIZE(cherry_pick) - 1, cherry_pick },
+               { KEYMAP_GENERIC, 'G', ARRAY_SIZE(gc) - 1, gc },
        };
        int i;
 
        for (i = 0; i < ARRAY_SIZE(reqs); i++) {
                enum request req;
 
-               req = add_run_request(reqs[i].keymap, reqs[i].key, 1, reqs[i].argv);
+               req = add_run_request(reqs[i].keymap, reqs[i].key, reqs[i].argc, reqs[i].argv);
                if (req != REQ_NONE)
                        add_keybinding(reqs[i].keymap, req, reqs[i].key);
        }
@@ -1051,11 +1373,11 @@ static struct int_map attr_map[] = {
 
 static int   config_lineno;
 static bool  config_errors;
-static char *config_msg;
+static const char *config_msg;
 
 /* Wants: object fgcolor bgcolor [attr] */
 static int
-option_color_command(int argc, char *argv[])
+option_color_command(int argc, const char *argv[])
 {
        struct line_info *info;
 
@@ -1098,9 +1420,17 @@ static bool parse_bool(const char *s)
                !strcmp(s, "yes")) ? TRUE : FALSE;
 }
 
+static int
+parse_int(const char *s, int default_value, int min, int max)
+{
+       int value = atoi(s);
+
+       return (value < min || value > max) ? default_value : value;
+}
+
 /* Wants: name = value */
 static int
-option_set_command(int argc, char *argv[])
+option_set_command(int argc, const char *argv[])
 {
        if (argc != 3) {
                config_msg = "Wrong number of arguments given to set command";
@@ -1143,28 +1473,32 @@ option_set_command(int argc, char *argv[])
        }
 
        if (!strcmp(argv[0], "line-number-interval")) {
-               opt_num_interval = atoi(argv[2]);
+               opt_num_interval = parse_int(argv[2], opt_num_interval, 1, 1024);
+               return OK;
+       }
+
+       if (!strcmp(argv[0], "author-width")) {
+               opt_author_cols = parse_int(argv[2], opt_author_cols, 0, 1024);
                return OK;
        }
 
        if (!strcmp(argv[0], "tab-size")) {
-               opt_tab_size = atoi(argv[2]);
+               opt_tab_size = parse_int(argv[2], opt_tab_size, 1, 1024);
                return OK;
        }
 
        if (!strcmp(argv[0], "commit-encoding")) {
-               char *arg = argv[2];
-               int delimiter = *arg;
-               int i;
+               const char *arg = argv[2];
+               int arglen = strlen(arg);
 
-               switch (delimiter) {
+               switch (arg[0]) {
                case '"':
                case '\'':
-                       for (arg++, i = 0; arg[i]; i++)
-                               if (arg[i] == delimiter) {
-                                       arg[i] = 0;
-                                       break;
-                               }
+                       if (arglen == 1 || arg[arglen - 1] != arg[0]) {
+                               config_msg = "Unmatched quotation";
+                               return ERR;
+                       }
+                       arg += 1; arglen -= 2;
                default:
                        string_ncopy(opt_encoding, arg, strlen(arg));
                        return OK;
@@ -1177,7 +1511,7 @@ option_set_command(int argc, char *argv[])
 
 /* Wants: mode request key */
 static int
-option_bind_command(int argc, char *argv[])
+option_bind_command(int argc, const char *argv[])
 {
        enum request request;
        int keymap;
@@ -1226,24 +1560,14 @@ option_bind_command(int argc, char *argv[])
 }
 
 static int
-set_option(char *opt, char *value)
+set_option(const char *opt, char *value)
 {
-       char *argv[16];
-       int valuelen;
+       const char *argv[SIZEOF_ARG];
        int argc = 0;
 
-       /* Tokenize */
-       while (argc < ARRAY_SIZE(argv) && (valuelen = strcspn(value, " \t"))) {
-               argv[argc++] = value;
-               value += valuelen;
-
-               /* Nothing more to tokenize or last available token. */
-               if (!*value || argc >= ARRAY_SIZE(argv))
-                       break;
-
-               *value++ = 0;
-               while (isspace(*value))
-                       value++;
+       if (!argv_from_string(argv, &argc, value)) {
+               config_msg = "Too many option arguments";
+               return ERR;
        }
 
        if (!strcmp(opt, "color"))
@@ -1302,17 +1626,16 @@ read_option(char *opt, size_t optlen, char *value, size_t valuelen)
 static void
 load_option_file(const char *path)
 {
-       FILE *file;
+       struct io io = {};
 
        /* It's ok that the file doesn't exist. */
-       file = fopen(path, "r");
-       if (!file)
+       if (!io_open(&io, path))
                return;
 
        config_lineno = 0;
        config_errors = FALSE;
 
-       if (read_properties(file, " \t", read_option) == ERR ||
+       if (read_properties(&io, " \t", read_option) == ERR ||
            config_errors == TRUE)
                fprintf(stderr, "Errors while loading %s.\n", path);
 }
@@ -1320,9 +1643,9 @@ load_option_file(const char *path)
 static int
 load_options(void)
 {
-       char *home = getenv("HOME");
-       char *tigrc_user = getenv("TIGRC_USER");
-       char *tigrc_system = getenv("TIGRC_SYSTEM");
+       const char *home = getenv("HOME");
+       const char *tigrc_user = getenv("TIGRC_USER");
+       const char *tigrc_system = getenv("TIGRC_SYSTEM");
        char buf[SIZEOF_STR];
 
        add_builtin_run_requests();
@@ -1371,7 +1694,6 @@ static char ref_head[SIZEOF_REF]  = "HEAD";
 
 struct view {
        const char *name;       /* View name */
-       const char *cmd_fmt;    /* Default command line format */
        const char *cmd_env;    /* Command line set via environment */
        const char *id;         /* Points to either of ref_{head,commit,blob} */
 
@@ -1380,7 +1702,6 @@ struct view {
        enum keymap keymap;     /* What keymap does this view have */
        bool git_dir;           /* Whether the view requires a git directory. */
 
-       char cmd[SIZEOF_STR];   /* Command buffer */
        char ref[SIZEOF_REF];   /* Hovered commit reference */
        char vid[SIZEOF_REF];   /* View ID. Set to id member when updating. */
 
@@ -1404,7 +1725,6 @@ struct view {
        size_t lines;           /* Total number of lines */
        struct line *line;      /* Line index */
        size_t line_alloc;      /* Total number of allocated lines */
-       size_t line_size;       /* Total number of used lines */
        unsigned int digits;    /* Number of digits in the lines member. */
 
        /* Drawing */
@@ -1413,13 +1733,17 @@ struct view {
        unsigned long col;      /* Column when drawing. */
 
        /* Loading */
-       FILE *pipe;
+       struct io io;
+       struct io *pipe;
        time_t start_time;
+       time_t update_secs;
 };
 
 struct view_ops {
        /* What type of content being displayed. Used in the title bar. */
        const char *type;
+       /* Default command arguments. */
+       const char **argv;
        /* Open and reads in all view content. */
        bool (*open)(struct view *view);
        /* Read one line; updates view->line. */
@@ -1434,26 +1758,28 @@ struct view_ops {
        void (*select)(struct view *view, struct line *line);
 };
 
-static struct view_ops pager_ops;
-static struct view_ops main_ops;
-static struct view_ops tree_ops;
-static struct view_ops blob_ops;
 static struct view_ops blame_ops;
+static struct view_ops blob_ops;
+static struct view_ops diff_ops;
 static struct view_ops help_ops;
-static struct view_ops status_ops;
+static struct view_ops log_ops;
+static struct view_ops main_ops;
+static struct view_ops pager_ops;
 static struct view_ops stage_ops;
+static struct view_ops status_ops;
+static struct view_ops tree_ops;
 
-#define VIEW_STR(name, cmd, env, ref, ops, map, git) \
-       { name, cmd, #env, ref, ops, map, git }
+#define VIEW_STR(name, env, ref, ops, map, git) \
+       { name, #env, ref, ops, map, git }
 
 #define VIEW_(id, name, ops, git, ref) \
-       VIEW_STR(name, TIG_##id##_CMD,  TIG_##id##_CMD, ref, ops, KEYMAP_##id, git)
+       VIEW_STR(name, TIG_##id##_CMD, ref, ops, KEYMAP_##id, git)
 
 
 static struct view views[] = {
        VIEW_(MAIN,   "main",   &main_ops,   TRUE,  ref_head),
-       VIEW_(DIFF,   "diff",   &pager_ops,  TRUE,  ref_commit),
-       VIEW_(LOG,    "log",    &pager_ops,  TRUE,  ref_head),
+       VIEW_(DIFF,   "diff",   &diff_ops,   TRUE,  ref_commit),
+       VIEW_(LOG,    "log",    &log_ops,    TRUE,  ref_head),
        VIEW_(TREE,   "tree",   &tree_ops,   TRUE,  ref_commit),
        VIEW_(BLOB,   "blob",   &blob_ops,   TRUE,  ref_blob),
        VIEW_(BLAME,  "blame",  &blame_ops,  TRUE,  ref_commit),
@@ -1615,7 +1941,7 @@ draw_graphic(struct view *view, enum line_type type, chtype graphic[], size_t si
 }
 
 static bool
-draw_field(struct view *view, enum line_type type, char *text, int len, bool trim)
+draw_field(struct view *view, enum line_type type, const char *text, int len, bool trim)
 {
        int max = MIN(view->width - view->col, len);
        int col;
@@ -1658,17 +1984,18 @@ draw_view_line(struct view *view, unsigned int lineno)
        line = &view->line[view->offset + lineno];
 
        wmove(view->win, lineno, 0);
+       if (line->cleareol)
+               wclrtoeol(view->win);
        view->col = 0;
        view->curline = line;
        view->curtype = LINE_NONE;
        line->selected = FALSE;
+       line->dirty = line->cleareol = 0;
 
        if (selected) {
                set_view_attr(view, LINE_CURSOR);
                line->selected = TRUE;
                view->ops->select(view, line);
-       } else if (line->selected) {
-               wclrtoeol(view->win);
        }
 
        scrollok(view->win, FALSE);
@@ -1685,11 +2012,10 @@ redraw_view_dirty(struct view *view)
        int lineno;
 
        for (lineno = 0; lineno < view->height; lineno++) {
-               struct line *line = &view->line[view->offset + lineno];
-
-               if (!line->dirty)
+               if (view->offset + lineno >= view->lines)
+                       break;
+               if (!view->line[view->offset + lineno].dirty)
                        continue;
-               line->dirty = 0;
                dirty = TRUE;
                if (!draw_view_line(view, lineno))
                        break;
@@ -1738,25 +2064,26 @@ update_view_title(struct view *view)
 
        assert(view_is_displayed(view));
 
-       if (view != VIEW(REQ_VIEW_STATUS) && (view->lines || view->pipe)) {
+       if (view != VIEW(REQ_VIEW_STATUS) && view->lines) {
                unsigned int view_lines = view->offset + view->height;
                unsigned int lines = view->lines
                                   ? MIN(view_lines, view->lines) * 100 / view->lines
                                   : 0;
 
-               string_format_from(state, &statelen, "- %s %d of %d (%d%%)",
+               string_format_from(state, &statelen, " - %s %d of %d (%d%%)",
                                   view->ops->type,
                                   view->lineno + 1,
                                   view->lines,
                                   lines);
 
-               if (view->pipe) {
-                       time_t secs = time(NULL) - view->start_time;
+       }
 
-                       /* Three git seconds are a long time ... */
-                       if (secs > 2)
-                               string_format_from(state, &statelen, " %lds", secs);
-               }
+       if (view->pipe) {
+               time_t secs = time(NULL) - view->start_time;
+
+               /* Three git seconds are a long time ... */
+               if (secs > 2)
+                       string_format_from(state, &statelen, " loading %lds", secs);
        }
 
        string_format_from(buf, &bufpos, "[%s]", view->name);
@@ -1770,7 +2097,7 @@ update_view_title(struct view *view)
        }
 
        if (statelen && bufpos < view->width) {
-               string_format_from(buf, &bufpos, " %s", state);
+               string_format_from(buf, &bufpos, "%s", state);
        }
 
        if (view == display[current_view])
@@ -2161,52 +2488,149 @@ search_view(struct view *view, enum request request)
  */
 
 static void
-end_update(struct view *view)
+reset_view(struct view *view)
+{
+       int i;
+
+       for (i = 0; i < view->lines; i++)
+               free(view->line[i].data);
+       free(view->line);
+
+       view->line = NULL;
+       view->offset = 0;
+       view->lines  = 0;
+       view->lineno = 0;
+       view->line_alloc = 0;
+       view->vid[0] = 0;
+       view->update_secs = 0;
+}
+
+static void
+free_argv(const char *argv[])
+{
+       int argc;
+
+       for (argc = 0; argv[argc]; argc++)
+               free((void *) argv[argc]);
+}
+
+static bool
+format_argv(const char *dst_argv[], const char *src_argv[], enum format_flags flags)
+{
+       char buf[SIZEOF_STR];
+       int argc;
+       bool noreplace = flags == FORMAT_NONE;
+
+       free_argv(dst_argv);
+
+       for (argc = 0; src_argv[argc]; argc++) {
+               const char *arg = src_argv[argc];
+               size_t bufpos = 0;
+
+               while (arg) {
+                       char *next = strstr(arg, "%(");
+                       int len = next - arg;
+                       const char *value;
+
+                       if (!next || noreplace) {
+                               if (flags == FORMAT_DASH && !strcmp(arg, "--"))
+                                       noreplace = TRUE;
+                               len = strlen(arg);
+                               value = "";
+
+                       } else if (!prefixcmp(next, "%(directory)")) {
+                               value = opt_path;
+
+                       } else if (!prefixcmp(next, "%(file)")) {
+                               value = opt_file;
+
+                       } else if (!prefixcmp(next, "%(ref)")) {
+                               value = *opt_ref ? opt_ref : "HEAD";
+
+                       } else if (!prefixcmp(next, "%(head)")) {
+                               value = ref_head;
+
+                       } else if (!prefixcmp(next, "%(commit)")) {
+                               value = ref_commit;
+
+                       } else if (!prefixcmp(next, "%(blob)")) {
+                               value = ref_blob;
+
+                       } else {
+                               report("Unknown replacement: `%s`", next);
+                               return FALSE;
+                       }
+
+                       if (!string_format_from(buf, &bufpos, "%.*s%s", len, arg, value))
+                               return FALSE;
+
+                       arg = next && !noreplace ? strchr(next, ')') + 1 : NULL;
+               }
+
+               dst_argv[argc] = strdup(buf);
+               if (!dst_argv[argc])
+                       break;
+       }
+
+       dst_argv[argc] = NULL;
+
+       return src_argv[argc] == NULL;
+}
+
+static void
+end_update(struct view *view, bool force)
 {
        if (!view->pipe)
                return;
+       while (!view->ops->read(view, NULL))
+               if (!force)
+                       return;
        set_nonblocking_input(FALSE);
-       if (view->pipe == stdin)
-               fclose(view->pipe);
-       else
-               pclose(view->pipe);
+       if (force)
+               kill_io(view->pipe);
+       done_io(view->pipe);
        view->pipe = NULL;
 }
 
+static void
+setup_update(struct view *view, const char *vid)
+{
+       set_nonblocking_input(TRUE);
+       reset_view(view);
+       string_copy_rev(view->vid, vid);
+       view->pipe = &view->io;
+       view->start_time = time(NULL);
+}
+
 static bool
-begin_update(struct view *view)
+prepare_update(struct view *view, const char *argv[], const char *dir,
+              enum format_flags flags)
 {
        if (view->pipe)
-               end_update(view);
-
-       if (opt_cmd[0]) {
-               string_copy(view->cmd, opt_cmd);
-               opt_cmd[0] = 0;
-               /* When running random commands, initially show the
-                * command in the title. However, it maybe later be
-                * overwritten if a commit line is selected. */
-               if (view == VIEW(REQ_VIEW_PAGER))
-                       string_copy(view->ref, view->cmd);
-               else
-                       view->ref[0] = 0;
-
-       } else if (view == VIEW(REQ_VIEW_TREE)) {
-               const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;
-               char path[SIZEOF_STR];
+               end_update(view, TRUE);
+       return init_io_rd(&view->io, argv, dir, flags);
+}
 
-               if (strcmp(view->vid, view->id))
-                       opt_path[0] = path[0] = 0;
-               else if (sq_quote(path, 0, opt_path) >= sizeof(path))
-                       return FALSE;
+static bool
+prepare_update_file(struct view *view, const char *name)
+{
+       if (view->pipe)
+               end_update(view, TRUE);
+       return io_open(&view->io, name);
+}
 
-               if (!string_format(view->cmd, format, view->id, path))
+static bool
+begin_update(struct view *view, bool refresh)
+{
+       if (refresh) {
+               if (!start_io(&view->io))
                        return FALSE;
 
        } else {
-               const char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;
-               const char *id = view->id;
+               if (view == VIEW(REQ_VIEW_TREE) && strcmp(view->vid, view->id))
+                       opt_path[0] = 0;
 
-               if (!string_format(view->cmd, format, id, id, id, id, id))
+               if (!run_io_rd(&view->io, view->ops->argv, FORMAT_ALL))
                        return FALSE;
 
                /* Put the current ref_* value to the view title ref
@@ -2216,36 +2640,7 @@ begin_update(struct view *view)
                string_copy_rev(view->ref, view->id);
        }
 
-       /* Special case for the pager view. */
-       if (opt_pipe) {
-               view->pipe = opt_pipe;
-               opt_pipe = NULL;
-       } else {
-               view->pipe = popen(view->cmd, "r");
-       }
-
-       if (!view->pipe)
-               return FALSE;
-
-       set_nonblocking_input(TRUE);
-
-       view->offset = 0;
-       view->lines  = 0;
-       view->lineno = 0;
-       string_copy_rev(view->vid, view->id);
-
-       if (view->line) {
-               int i;
-
-               for (i = 0; i < view->lines; i++)
-                       if (view->line[i].data)
-                               free(view->line[i].data);
-
-               free(view->line);
-               view->line = NULL;
-       }
-
-       view->start_time = time(NULL);
+       setup_update(view, view->id);
 
        return TRUE;
 }
@@ -2277,42 +2672,42 @@ realloc_lines(struct view *view, size_t line_size)
 
        view->line = tmp;
        view->line_alloc = alloc;
-       view->line_size = line_size;
        return view->line;
 }
 
 static bool
 update_view(struct view *view)
 {
-       char in_buffer[BUFSIZ];
        char out_buffer[BUFSIZ * 2];
        char *line;
-       /* The number of lines to read. If too low it will cause too much
-        * redrawing (and possible flickering), if too high responsiveness
-        * will suffer. */
-       unsigned long lines = view->height;
-       int redraw_from = -1;
+       /* Clear the view and redraw everything since the tree sorting
+        * might have rearranged things. */
+       bool redraw = view->lines == 0;
+       bool can_read = TRUE;
 
        if (!view->pipe)
                return TRUE;
 
-       /* Only redraw if lines are visible. */
-       if (view->offset + view->height >= view->lines)
-               redraw_from = view->lines - view->offset;
+       if (!io_can_read(view->pipe)) {
+               if (view->lines == 0) {
+                       time_t secs = time(NULL) - view->start_time;
 
-       /* FIXME: This is probably not perfect for backgrounded views. */
-       if (!realloc_lines(view, view->lines + lines))
-               goto alloc_error;
+                       if (secs > view->update_secs) {
+                               if (view->update_secs == 0)
+                                       redraw_view(view);
+                               update_view_title(view);
+                               view->update_secs = secs;
+                       }
+               }
+               return TRUE;
+       }
 
-       while ((line = fgets(in_buffer, sizeof(in_buffer), view->pipe))) {
+       for (; (line = io_get(view->pipe, '\n', can_read)); can_read = FALSE) {
                size_t linelen = strlen(line);
 
-               if (linelen)
-                       line[linelen - 1] = 0;
-
                if (opt_iconv != ICONV_NONE) {
                        ICONV_CONST char *inbuf = line;
-                       size_t inlen = linelen;
+                       size_t inlen = linelen + 1;
 
                        char *outbuf = out_buffer;
                        size_t outlen = sizeof(out_buffer);
@@ -2328,99 +2723,89 @@ update_view(struct view *view)
 
                if (!view->ops->read(view, line))
                        goto alloc_error;
-
-               if (lines-- == 1)
-                       break;
        }
 
        {
+               unsigned long lines = view->lines;
                int digits;
 
-               lines = view->lines;
                for (digits = 0; lines; digits++)
                        lines /= 10;
 
                /* Keep the displayed view in sync with line number scaling. */
                if (digits != view->digits) {
                        view->digits = digits;
-                       redraw_from = 0;
+                       if (opt_line_number || view == VIEW(REQ_VIEW_BLAME))
+                               redraw = TRUE;
                }
        }
 
-       if (!view_is_displayed(view))
-               goto check_pipe;
-
-       if (view == VIEW(REQ_VIEW_TREE)) {
-               /* Clear the view and redraw everything since the tree sorting
-                * might have rearranged things. */
-               redraw_view(view);
-
-       } else if (redraw_from >= 0) {
-               /* If this is an incremental update, redraw the previous line
-                * since for commits some members could have changed when
-                * loading the main view. */
-               if (redraw_from > 0)
-                       redraw_from--;
+       if (io_error(view->pipe)) {
+               report("Failed to read: %s", io_strerror(view->pipe));
+               end_update(view, TRUE);
 
-               /* Since revision graph visualization requires knowledge
-                * about the parent commit, it causes a further one-off
-                * needed to be redrawn for incremental updates. */
-               if (redraw_from > 0 && opt_rev_graph)
-                       redraw_from--;
-
-               /* Incrementally draw avoids flickering. */
-               redraw_view_from(view, redraw_from);
+       } else if (io_eof(view->pipe)) {
+               report("");
+               end_update(view, FALSE);
        }
 
-       if (view == VIEW(REQ_VIEW_BLAME))
+       if (!view_is_displayed(view))
+               return TRUE;
+
+       if (redraw)
+               redraw_view_from(view, 0);
+       else
                redraw_view_dirty(view);
 
        /* Update the title _after_ the redraw so that if the redraw picks up a
         * commit reference in view->ref it'll be available here. */
        update_view_title(view);
-
-check_pipe:
-       if (ferror(view->pipe)) {
-               report("Failed to read: %s", strerror(errno));
-               goto end;
-
-       } else if (feof(view->pipe)) {
-               report("");
-               goto end;
-       }
-
        return TRUE;
 
 alloc_error:
        report("Allocation failure");
-
-end:
-       if (view->ops->read(view, NULL))
-               end_update(view);
+       end_update(view, TRUE);
        return FALSE;
 }
 
 static struct line *
 add_line_data(struct view *view, void *data, enum line_type type)
 {
-       struct line *line = &view->line[view->lines++];
+       struct line *line;
+
+       if (!realloc_lines(view, view->lines + 1))
+               return NULL;
 
+       line = &view->line[view->lines++];
        memset(line, 0, sizeof(*line));
        line->type = type;
        line->data = data;
+       line->dirty = 1;
 
        return line;
 }
 
 static struct line *
-add_line_text(struct view *view, char *data, enum line_type type)
+add_line_text(struct view *view, const char *text, enum line_type type)
 {
-       if (data)
-               data = strdup(data);
+       char *data = text ? strdup(text) : NULL;
 
        return data ? add_line_data(view, data, type) : NULL;
 }
 
+static struct line *
+add_line_format(struct view *view, enum line_type type, const char *fmt, ...)
+{
+       char buf[SIZEOF_STR];
+       va_list args;
+
+       va_start(args, fmt);
+       if (vsnprintf(buf, sizeof(buf), fmt, args) >= sizeof(buf))
+               buf[0] = 0;
+       va_end(args);
+
+       return buf[0] ? add_line_text(view, buf, type) : NULL;
+}
 
 /*
  * View opening
@@ -2431,7 +2816,9 @@ enum open_flags {
        OPEN_SPLIT = 1,         /* Split current view. */
        OPEN_BACKGROUNDED = 2,  /* Backgrounded. */
        OPEN_RELOAD = 4,        /* Reload view even if it is the current. */
-       OPEN_NOMAXIMIZE = 8     /* Do not maximize the current view. */
+       OPEN_NOMAXIMIZE = 8,    /* Do not maximize the current view. */
+       OPEN_REFRESH = 16,      /* Refresh view using previous command. */
+       OPEN_PREPARED = 32,     /* Open already prepared command. */
 };
 
 static void
@@ -2439,8 +2826,8 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
 {
        bool backgrounded = !!(flags & OPEN_BACKGROUNDED);
        bool split = !!(flags & OPEN_SPLIT);
-       bool reload = !!(flags & OPEN_RELOAD);
-       bool nomaximize = !!(flags & OPEN_NOMAXIMIZE);
+       bool reload = !!(flags & (OPEN_RELOAD | OPEN_REFRESH | OPEN_PREPARED));
+       bool nomaximize = !!(flags & (OPEN_NOMAXIMIZE | OPEN_REFRESH));
        struct view *view = VIEW(request);
        int nviews = displayed_views();
        struct view *base_view = display[0];
@@ -2472,6 +2859,9 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
            (nviews == 1 && base_view != display[0]))
                resize_display();
 
+       if (view->pipe)
+               end_update(view, TRUE);
+
        if (view->ops->open) {
                if (!view->ops->open(view)) {
                        report("Failed to load %s view", view->name);
@@ -2479,7 +2869,7 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
                }
 
        } else if ((reload || strcmp(view->vid, view->id)) &&
-                  !begin_update(view)) {
+                  !begin_update(view, flags & (OPEN_REFRESH | OPEN_PREPARED))) {
                report("Failed to load %s view", view->name);
                return;
        }
@@ -2507,7 +2897,7 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
                 * the screen. */
                werase(view->win);
                report("");
-       } else {
+       } else if (view_is_displayed(view)) {
                redraw_view(view);
                report("");
        }
@@ -2519,13 +2909,13 @@ open_view(struct view *prev, enum request request, enum open_flags flags)
 }
 
 static void
-open_external_viewer(const char *cmd)
+open_external_viewer(const char *argv[], const char *dir)
 {
        def_prog_mode();           /* save current tty modes */
        endwin();                  /* restore original tty modes */
-       system(cmd);
+       run_io_fg(argv, dir);
        fprintf(stderr, "Press Enter to continue");
-       getc(stdin);
+       getc(opt_tty);
        reset_prog_mode();
        redraw_display();
 }
@@ -2533,22 +2923,16 @@ open_external_viewer(const char *cmd)
 static void
 open_mergetool(const char *file)
 {
-       char cmd[SIZEOF_STR];
-       char file_sq[SIZEOF_STR];
+       const char *mergetool_argv[] = { "git", "mergetool", file, NULL };
 
-       if (sq_quote(file_sq, 0, file) < sizeof(file_sq) &&
-           string_format(cmd, "git mergetool %s", file_sq)) {
-               open_external_viewer(cmd);
-       }
+       open_external_viewer(mergetool_argv, opt_cdup);
 }
 
 static void
 open_editor(bool from_root, const char *file)
 {
-       char cmd[SIZEOF_STR];
-       char file_sq[SIZEOF_STR];
-       char *editor;
-       char *prefix = from_root ? opt_cdup : "";
+       const char *editor_argv[] = { "vi", file, NULL };
+       const char *editor;
 
        editor = getenv("GIT_EDITOR");
        if (!editor && *opt_editor)
@@ -2560,60 +2944,24 @@ open_editor(bool from_root, const char *file)
        if (!editor)
                editor = "vi";
 
-       if (sq_quote(file_sq, 0, file) < sizeof(file_sq) &&
-           string_format(cmd, "%s %s%s", editor, prefix, file_sq)) {
-               open_external_viewer(cmd);
-       }
+       editor_argv[0] = editor;
+       open_external_viewer(editor_argv, from_root ? opt_cdup : NULL);
 }
 
 static void
 open_run_request(enum request request)
 {
        struct run_request *req = get_run_request(request);
-       char buf[SIZEOF_STR * 2];
-       size_t bufpos;
-       char *cmd;
+       const char *argv[ARRAY_SIZE(req->argv)] = { NULL };
 
        if (!req) {
                report("Unknown run request");
                return;
        }
 
-       bufpos = 0;
-       cmd = req->cmd;
-
-       while (cmd) {
-               char *next = strstr(cmd, "%(");
-               int len = next - cmd;
-               char *value;
-
-               if (!next) {
-                       len = strlen(cmd);
-                       value = "";
-
-               } else if (!strncmp(next, "%(head)", 7)) {
-                       value = ref_head;
-
-               } else if (!strncmp(next, "%(commit)", 9)) {
-                       value = ref_commit;
-
-               } else if (!strncmp(next, "%(blob)", 7)) {
-                       value = ref_blob;
-
-               } else {
-                       report("Unknown replacement in run request: `%s`", req->cmd);
-                       return;
-               }
-
-               if (!string_format_from(buf, &bufpos, "%.*s%s", len, cmd, value))
-                       return;
-
-               if (next)
-                       next = strchr(next, ')') + 1;
-               cmd = next;
-       }
-
-       open_external_viewer(buf);
+       if (format_argv(argv, req->argv, FORMAT_ALL))
+               open_external_viewer(argv, NULL);
+       free_argv(argv);
 }
 
 /*
@@ -2634,6 +2982,8 @@ view_driver(struct view *view, enum request request)
                open_run_request(request);
                /* FIXME: When all views can refresh always do this. */
                if (view == VIEW(REQ_VIEW_STATUS) ||
+                   view == VIEW(REQ_VIEW_MAIN) ||
+                   view == VIEW(REQ_VIEW_LOG) ||
                    view == VIEW(REQ_VIEW_STAGE))
                        request = REQ_REFRESH;
                else
@@ -2682,7 +3032,7 @@ view_driver(struct view *view, enum request request)
                break;
 
        case REQ_VIEW_PAGER:
-               if (!opt_pipe && !VIEW(REQ_VIEW_PAGER)->lines) {
+               if (!VIEW(REQ_VIEW_PAGER)->pipe && !VIEW(REQ_VIEW_PAGER)->lines) {
                        report("No pager content, press %s to run command from prompt",
                               get_key(REQ_PROMPT));
                        break;
@@ -2793,11 +3143,6 @@ view_driver(struct view *view, enum request request)
                redraw_display();
                break;
 
-       case REQ_PROMPT:
-               /* Always reload^Wrerun commands from the prompt. */
-               open_view(view, opt_request, OPEN_RELOAD);
-               break;
-
        case REQ_SEARCH:
        case REQ_SEARCH_BACK:
                search_view(view, request);
@@ -2813,7 +3158,7 @@ view_driver(struct view *view, enum request request)
                        view = &views[i];
                        if (view->pipe)
                                report("Stopped loading the %s view", view->name),
-                       end_update(view);
+                       end_update(view, TRUE);
                }
                break;
 
@@ -2832,12 +3177,10 @@ view_driver(struct view *view, enum request request)
                report("Nothing to edit");
                break;
 
-
        case REQ_ENTER:
                report("Nothing to enter");
                break;
 
-
        case REQ_VIEW_CLOSE:
                /* XXX: Mark closed views by letting view->parent point to the
                 * view itself. Parents to closed view should never be
@@ -2850,6 +3193,7 @@ view_driver(struct view *view, enum request request)
                        view->parent = view;
                        resize_display();
                        redraw_display();
+                       report("");
                        break;
                }
                /* Fall-through */
@@ -2857,7 +3201,6 @@ view_driver(struct view *view, enum request request)
                return FALSE;
 
        default:
-               /* An unknown key will show most commonly used commands. */
                report("Unknown key, press 'h' for help");
                return TRUE;
        }
@@ -2883,22 +3226,14 @@ pager_draw(struct view *view, struct line *line, unsigned int lineno)
 }
 
 static bool
-add_describe_ref(char *buf, size_t *bufpos, char *commit_id, const char *sep)
+add_describe_ref(char *buf, size_t *bufpos, const char *commit_id, const char *sep)
 {
+       const char *describe_argv[] = { "git", "describe", commit_id, NULL };
        char refbuf[SIZEOF_STR];
        char *ref = NULL;
-       FILE *pipe;
 
-       if (!string_format(refbuf, "git describe %s 2>/dev/null", commit_id))
-               return TRUE;
-
-       pipe = popen(refbuf, "r");
-       if (!pipe)
-               return TRUE;
-
-       if ((ref = fgets(refbuf, sizeof(refbuf), pipe)))
-               ref = chomp_string(ref);
-       pclose(pipe);
+       if (run_io_buf(describe_argv, refbuf, sizeof(refbuf)))
+               ref = chomp_string(refbuf);
 
        if (!ref || !*ref)
                return TRUE;
@@ -2931,8 +3266,8 @@ add_pager_refs(struct view *view, struct line *line)
 
        do {
                struct ref *ref = refs[refpos];
-               char *fmt = ref->tag    ? "%s[%s]" :
-                           ref->remote ? "%s<%s>" : "%s%s";
+               const char *fmt = ref->tag    ? "%s[%s]" :
+                                 ref->remote ? "%s<%s>" : "%s%s";
 
                if (!string_format_from(buf, &bufpos, fmt, sep, ref->name))
                        return;
@@ -2951,9 +3286,6 @@ try_add_describe_ref:
        if (bufpos == 0)
                return;
 
-       if (!realloc_lines(view, view->line_size + 1))
-               return;
-
        add_line_text(view, buf, LINE_PP_REFS);
 }
 
@@ -3036,6 +3368,7 @@ pager_select(struct view *view, struct line *line)
 static struct view_ops pager_ops = {
        "line",
        NULL,
+       NULL,
        pager_read,
        pager_draw,
        pager_request,
@@ -3043,6 +3376,49 @@ static struct view_ops pager_ops = {
        pager_select,
 };
 
+static const char *log_argv[SIZEOF_ARG] = {
+       "git", "log", "--no-color", "--cc", "--stat", "-n100", "%(head)", NULL
+};
+
+static enum request
+log_request(struct view *view, enum request request, struct line *line)
+{
+       switch (request) {
+       case REQ_REFRESH:
+               load_refs();
+               open_view(view, REQ_VIEW_LOG, OPEN_REFRESH);
+               return REQ_NONE;
+       default:
+               return pager_request(view, request, line);
+       }
+}
+
+static struct view_ops log_ops = {
+       "line",
+       log_argv,
+       NULL,
+       pager_read,
+       pager_draw,
+       log_request,
+       pager_grep,
+       pager_select,
+};
+
+static const char *diff_argv[SIZEOF_ARG] = {
+       "git", "show", "--pretty=fuller", "--no-color", "--root",
+               "--patch-with-stat", "--find-copies-harder", "-C", "%(commit)", NULL
+};
+
+static struct view_ops diff_ops = {
+       "line",
+       diff_argv,
+       NULL,
+       pager_read,
+       pager_draw,
+       pager_request,
+       pager_grep,
+       pager_select,
+};
 
 /*
  * Help backend
@@ -3051,7 +3427,6 @@ static struct view_ops pager_ops = {
 static bool
 help_open(struct view *view)
 {
-       char buf[BUFSIZ];
        int lines = ARRAY_SIZE(req_info) + 2;
        int i;
 
@@ -3071,7 +3446,7 @@ help_open(struct view *view)
        add_line_text(view, "Quick reference for tig keybindings:", LINE_DEFAULT);
 
        for (i = 0; i < ARRAY_SIZE(req_info); i++) {
-               char *key;
+               const char *key;
 
                if (req_info[i].request == REQ_NONE)
                        continue;
@@ -3086,10 +3461,8 @@ help_open(struct view *view)
                if (!*key)
                        key = "(no key defined)";
 
-               if (!string_format(buf, "    %-25s %s", key, req_info[i].help))
-                       continue;
-
-               add_line_text(view, buf, LINE_DEFAULT);
+               add_line_format(view, LINE_DEFAULT, "    %-25s %s",
+                               key, req_info[i].help);
        }
 
        if (run_requests) {
@@ -3099,7 +3472,10 @@ help_open(struct view *view)
 
        for (i = 0; i < run_requests; i++) {
                struct run_request *req = get_run_request(REQ_NONE + i + 1);
-               char *key;
+               const char *key;
+               char cmd[SIZEOF_STR];
+               size_t bufpos;
+               int argc;
 
                if (!req)
                        continue;
@@ -3108,12 +3484,13 @@ help_open(struct view *view)
                if (!*key)
                        key = "(no key defined)";
 
-               if (!string_format(buf, "    %-10s %-14s `%s`",
-                                  keymap_table[req->keymap].name,
-                                  key, req->cmd))
-                       continue;
+               for (bufpos = 0, argc = 0; req->argv[argc]; argc++)
+                       if (!string_format_from(cmd, &bufpos, "%s%s",
+                                               argc ? " " : "", req->argv[argc]))
+                               return REQ_NONE;
 
-               add_line_text(view, buf, LINE_DEFAULT);
+               add_line_format(view, LINE_DEFAULT, "    %-10s %-14s `%s`",
+                               keymap_table[req->keymap].name, key, cmd);
        }
 
        return TRUE;
@@ -3121,6 +3498,7 @@ help_open(struct view *view)
 
 static struct view_ops help_ops = {
        "line",
+       NULL,
        help_open,
        NULL,
        pager_draw,
@@ -3156,7 +3534,7 @@ pop_tree_stack_entry(void)
 }
 
 static void
-push_tree_stack_entry(char *name, unsigned long lineno)
+push_tree_stack_entry(const char *name, unsigned long lineno)
 {
        struct tree_stack_entry *entry = calloc(1, sizeof(*entry));
        size_t pathlen = strlen(opt_path);
@@ -3191,35 +3569,28 @@ push_tree_stack_entry(char *name, unsigned long lineno)
 
 #define TREE_UP_FORMAT "040000 tree %s\t.."
 
-static int
-tree_compare_entry(enum line_type type1, char *name1,
-                  enum line_type type2, char *name2)
+static const char *
+tree_path(struct line *line)
 {
-       if (type1 != type2) {
-               if (type1 == LINE_TREE_DIR)
-                       return -1;
-               return 1;
-       }
+       const char *path = line->data;
 
-       return strcmp(name1, name2);
+       return path + SIZEOF_TREE_ATTR;
 }
 
-static char *
-tree_path(struct line *line)
+static int
+tree_compare_entry(struct line *line1, struct line *line2)
 {
-       char *path = line->data;
-
-       return path + SIZEOF_TREE_ATTR;
+       if (line1->type != line2->type)
+               return line1->type == LINE_TREE_DIR ? -1 : 1;
+       return strcmp(tree_path(line1), tree_path(line2));
 }
 
 static bool
 tree_read(struct view *view, char *text)
 {
        size_t textlen = text ? strlen(text) : 0;
-       char buf[SIZEOF_STR];
-       unsigned long pos;
+       struct line *entry, *line;
        enum line_type type;
-       bool first_read = view->lines == 0;
 
        if (!text)
                return TRUE;
@@ -3229,21 +3600,9 @@ tree_read(struct view *view, char *text)
        type = text[STRING_SIZE("100644 ")] == 't'
             ? LINE_TREE_DIR : LINE_TREE_FILE;
 
-       if (first_read) {
-               /* Add path info line */
-               if (!string_format(buf, "Directory path /%s", opt_path) ||
-                   !realloc_lines(view, view->line_size + 1) ||
-                   !add_line_text(view, buf, LINE_DEFAULT))
-                       return FALSE;
-
-               /* Insert "link" to parent directory. */
-               if (*opt_path) {
-                       if (!string_format(buf, TREE_UP_FORMAT, view->ref) ||
-                           !realloc_lines(view, view->line_size + 1) ||
-                           !add_line_text(view, buf, LINE_TREE_DIR))
-                               return FALSE;
-               }
-       }
+       if (view->lines == 0 &&
+           !add_line_format(view, LINE_DEFAULT, "Directory path /%s", opt_path))
+               return FALSE;
 
        /* Strip the path part ... */
        if (*opt_path) {
@@ -3254,36 +3613,32 @@ tree_read(struct view *view, char *text)
                if (pathlen > striplen)
                        memmove(path, path + striplen,
                                pathlen - striplen + 1);
+
+               /* Insert "link" to parent directory. */
+               if (view->lines == 1 &&
+                   !add_line_format(view, LINE_TREE_DIR, TREE_UP_FORMAT, view->ref))
+                       return FALSE;
        }
 
-       /* Skip "Directory ..." and ".." line. */
-       for (pos = 1 + !!*opt_path; pos < view->lines; pos++) {
-               struct line *line = &view->line[pos];
-               char *path1 = tree_path(line);
-               char *path2 = text + SIZEOF_TREE_ATTR;
-               int cmp = tree_compare_entry(line->type, path1, type, path2);
+       entry = add_line_text(view, text, type);
+       if (!entry)
+               return FALSE;
+       text = entry->data;
 
-               if (cmp <= 0)
+       /* Skip "Directory ..." and ".." line. */
+       for (line = &view->line[1 + !!*opt_path]; line < entry; line++) {
+               if (tree_compare_entry(line, entry) <= 0)
                        continue;
 
-               text = strdup(text);
-               if (!text)
-                       return FALSE;
+               memmove(line + 1, line, (entry - line) * sizeof(*entry));
 
-               if (view->lines > pos)
-                       memmove(&view->line[pos + 1], &view->line[pos],
-                               (view->lines - pos) * sizeof(*line));
-
-               line = &view->line[pos];
                line->data = text;
                line->type = type;
-               view->lines++;
+               for (; line <= entry; line++)
+                       line->dirty = line->cleareol = 1;
                return TRUE;
        }
 
-       if (!add_line_text(view, text, type))
-               return FALSE;
-
        if (tree_lineno > view->lineno) {
                view->lineno = tree_lineno;
                tree_lineno = 0;
@@ -3297,30 +3652,41 @@ tree_request(struct view *view, enum request request, struct line *line)
 {
        enum open_flags flags;
 
-       if (request == REQ_VIEW_BLAME) {
-               char *filename = tree_path(line);
-
-               if (line->type == LINE_TREE_DIR) {
-                       report("Cannot show blame for directory %s", opt_path);
+       switch (request) {
+       case REQ_VIEW_BLAME:
+               if (line->type != LINE_TREE_FILE) {
+                       report("Blame only supported for files");
                        return REQ_NONE;
                }
 
                string_copy(opt_ref, view->vid);
-               string_format(opt_file, "%s%s", opt_path, filename);
                return request;
-       }
-       if (request == REQ_TREE_PARENT) {
-               if (*opt_path) {
-                       /* fake 'cd  ..' */
-                       request = REQ_ENTER;
-                       line = &view->line[1];
+
+       case REQ_EDIT:
+               if (line->type != LINE_TREE_FILE) {
+                       report("Edit only supported for files");
+               } else if (!is_head_commit(view->vid)) {
+                       report("Edit only supported for files in the current work tree");
                } else {
+                       open_editor(TRUE, opt_file);
+               }
+               return REQ_NONE;
+
+       case REQ_TREE_PARENT:
+               if (!*opt_path) {
                        /* quit view if at top of tree */
                        return REQ_VIEW_CLOSE;
                }
-       }
-       if (request != REQ_ENTER)
+               /* fake 'cd  ..' */
+               line = &view->line[1];
+               break;
+
+       case REQ_ENTER:
+               break;
+
+       default:
                return request;
+       }
 
        /* Cleanup the stack if the tree view is at a different tree. */
        while (!*opt_path && tree_stack)
@@ -3334,7 +3700,7 @@ tree_request(struct view *view, enum request request, struct line *line)
                        pop_tree_stack_entry();
 
                } else {
-                       char *basename = tree_path(line);
+                       const char *basename = tree_path(line);
 
                        push_tree_stack_entry(basename, view->lineno);
                }
@@ -3369,6 +3735,7 @@ tree_select(struct view *view, struct line *line)
 
        if (line->type == LINE_TREE_FILE) {
                string_copy_rev(ref_blob, text);
+               string_format(opt_file, "%s%s", opt_path, tree_path(line));
 
        } else if (line->type != LINE_TREE_DIR) {
                return;
@@ -3377,8 +3744,13 @@ tree_select(struct view *view, struct line *line)
        string_copy_rev(view->ref, text);
 }
 
+static const char *tree_argv[SIZEOF_ARG] = {
+       "git", "ls-tree", "%(commit)", "%(directory)", NULL
+};
+
 static struct view_ops tree_ops = {
        "file",
+       tree_argv,
        NULL,
        tree_read,
        pager_draw,
@@ -3395,8 +3767,13 @@ blob_read(struct view *view, char *line)
        return add_line_text(view, line, LINE_DEFAULT) != NULL;
 }
 
+static const char *blob_argv[SIZEOF_ARG] = {
+       "git", "cat-file", "blob", "%(blob)", NULL
+};
+
 static struct view_ops blob_ops = {
        "line",
+       blob_argv,
        NULL,
        blob_read,
        pager_draw,
@@ -3416,6 +3793,18 @@ static struct view_ops blob_ops = {
  *     reading output from git-blame.
  */
 
+static const char *blame_head_argv[] = {
+       "git", "blame", "--incremental", "--", "%(file)", NULL
+};
+
+static const char *blame_ref_argv[] = {
+       "git", "blame", "--incremental", "%(ref)", "--", "%(file)", NULL
+};
+
+static const char *blame_cat_file_argv[] = {
+       "git", "cat-file", "blob", "%(ref):%(file)", NULL
+};
+
 struct blame_commit {
        char id[SIZEOF_REV];            /* SHA1 ID. */
        char title[128];                /* First line of the commit message. */
@@ -3426,59 +3815,19 @@ struct blame_commit {
 
 struct blame {
        struct blame_commit *commit;
-       unsigned int header:1;
        char text[1];
 };
 
-#define BLAME_CAT_FILE_CMD "git cat-file blob %s:%s"
-#define BLAME_INCREMENTAL_CMD "git blame --incremental %s %s"
-
 static bool
 blame_open(struct view *view)
 {
-       char path[SIZEOF_STR];
-       char ref[SIZEOF_STR] = "";
-
-       if (sq_quote(path, 0, opt_file) >= sizeof(path))
-               return FALSE;
-
-       if (*opt_ref && sq_quote(ref, 0, opt_ref) >= sizeof(ref))
-               return FALSE;
-
-       if (*opt_ref) {
-               if (!string_format(view->cmd, BLAME_CAT_FILE_CMD, ref, path))
-                       return FALSE;
-       } else {
-               view->pipe = fopen(opt_file, "r");
-               if (!view->pipe &&
-                   !string_format(view->cmd, BLAME_CAT_FILE_CMD, "HEAD", path))
+       if (*opt_ref || !io_open(&view->io, opt_file)) {
+               if (!run_io_rd(&view->io, blame_cat_file_argv, FORMAT_ALL))
                        return FALSE;
        }
 
-       if (!view->pipe)
-               view->pipe = popen(view->cmd, "r");
-       if (!view->pipe)
-               return FALSE;
-
-       if (!string_format(view->cmd, BLAME_INCREMENTAL_CMD, ref, path))
-               return FALSE;
-
+       setup_update(view, opt_file);
        string_format(view->ref, "%s ...", opt_file);
-       string_copy_rev(view->vid, opt_file);
-       set_nonblocking_input(TRUE);
-
-       if (view->line) {
-               int i;
-
-               for (i = 0; i < view->lines; i++)
-                       free(view->line[i].data);
-               free(view->line);
-       }
-
-       view->lines = view->line_alloc = view->line_size = view->lineno = 0;
-       view->offset = view->lines  = view->lineno = 0;
-       view->line = NULL;
-       view->start_time = time(NULL);
 
        return TRUE;
 }
@@ -3508,9 +3857,9 @@ get_blame_commit(struct view *view, const char *id)
 }
 
 static bool
-parse_number(char **posref, size_t *number, size_t min, size_t max)
+parse_number(const char **posref, size_t *number, size_t min, size_t max)
 {
-       char *pos = *posref;
+       const char *pos = *posref;
 
        *posref = NULL;
        pos = strchr(pos + 1, ' ');
@@ -3525,11 +3874,11 @@ parse_number(char **posref, size_t *number, size_t min, size_t max)
 }
 
 static struct blame_commit *
-parse_blame_commit(struct view *view, char *text, int *blamed)
+parse_blame_commit(struct view *view, const char *text, int *blamed)
 {
        struct blame_commit *commit;
        struct blame *blame;
-       char *pos = text + SIZEOF_REV - 1;
+       const char *pos = text + SIZEOF_REV - 1;
        size_t lineno;
        size_t group;
 
@@ -3550,7 +3899,6 @@ parse_blame_commit(struct view *view, char *text, int *blamed)
 
                blame = line->data;
                blame->commit = commit;
-               blame->header = !group;
                line->dirty = 1;
        }
 
@@ -3558,32 +3906,29 @@ parse_blame_commit(struct view *view, char *text, int *blamed)
 }
 
 static bool
-blame_read_file(struct view *view, char *line)
+blame_read_file(struct view *view, const char *line, bool *read_file)
 {
        if (!line) {
-               FILE *pipe = NULL;
+               const char **argv = *opt_ref ? blame_ref_argv : blame_head_argv;
+               struct io io = {};
 
-               if (view->lines > 0)
-                       pipe = popen(view->cmd, "r");
-               else if (!view->parent)
+               if (view->lines == 0 && !view->parent)
                        die("No blame exist for %s", view->vid);
-               view->cmd[0] = 0;
-               if (!pipe) {
+
+               if (view->lines == 0 || !run_io_rd(&io, argv, FORMAT_ALL)) {
                        report("Failed to load blame data");
                        return TRUE;
                }
 
-               fclose(view->pipe);
-               view->pipe = pipe;
+               done_io(view->pipe);
+               view->io = io;
+               *read_file = FALSE;
                return FALSE;
 
        } else {
                size_t linelen = strlen(line);
                struct blame *blame = malloc(sizeof(*blame) + linelen);
 
-               if (!line)
-                       return FALSE;
-
                blame->commit = NULL;
                strncpy(blame->text, line, linelen);
                blame->text[linelen] = 0;
@@ -3609,14 +3954,16 @@ blame_read(struct view *view, char *line)
        static struct blame_commit *commit = NULL;
        static int blamed = 0;
        static time_t author_time;
+       static bool read_file = TRUE;
 
-       if (*view->cmd)
-               return blame_read_file(view, line);
+       if (read_file)
+               return blame_read_file(view, line, &read_file);
 
        if (!line) {
                /* Reset all! */
                commit = NULL;
                blamed = 0;
+               read_file = TRUE;
                string_format(view->ref, "%s", view->vid);
                if (view_is_displayed(view)) {
                        update_view_title(view);
@@ -3666,7 +4013,7 @@ blame_draw(struct view *view, struct line *line, unsigned int lineno)
 {
        struct blame *blame = line->data;
        struct tm *time = NULL;
-       char *id = NULL, *author = NULL;
+       const char *id = NULL, *author = NULL;
 
        if (blame->commit && *blame->commit->filename) {
                id = blame->commit->id;
@@ -3678,7 +4025,7 @@ blame_draw(struct view *view, struct line *line, unsigned int lineno)
                return TRUE;
 
        if (opt_author &&
-           draw_field(view, LINE_MAIN_AUTHOR, author, AUTHOR_COLS, TRUE))
+           draw_field(view, LINE_MAIN_AUTHOR, author, opt_author_cols, TRUE))
                return TRUE;
 
        if (draw_field(view, LINE_BLAME_ID, id, ID_COLS, FALSE))
@@ -3691,6 +4038,18 @@ blame_draw(struct view *view, struct line *line, unsigned int lineno)
        return TRUE;
 }
 
+static bool
+check_blame_commit(struct blame *blame)
+{
+       if (!blame->commit)
+               report("Commit data not loaded yet");
+       else if (!strcmp(blame->commit->id, NULL_ID))
+               report("No commit exist for the selected line");
+       else
+               return TRUE;
+       return FALSE;
+}
+
 static enum request
 blame_request(struct view *view, enum request request, struct line *line)
 {
@@ -3698,18 +4057,36 @@ blame_request(struct view *view, enum request request, struct line *line)
        struct blame *blame = line->data;
 
        switch (request) {
+       case REQ_VIEW_BLAME:
+               if (check_blame_commit(blame)) {
+                       string_copy(opt_ref, blame->commit->id);
+                       open_view(view, REQ_VIEW_BLAME, OPEN_REFRESH);
+               }
+               break;
+
        case REQ_ENTER:
                if (!blame->commit) {
                        report("No commit loaded yet");
                        break;
                }
 
-               if (!strcmp(blame->commit->id, NULL_ID)) {
-                       char path[SIZEOF_STR];
+               if (view_is_displayed(VIEW(REQ_VIEW_DIFF)) &&
+                   !strcmp(blame->commit->id, VIEW(REQ_VIEW_DIFF)->ref))
+                       break;
 
-                       if (sq_quote(path, 0, view->vid) >= sizeof(path))
+               if (!strcmp(blame->commit->id, NULL_ID)) {
+                       struct view *diff = VIEW(REQ_VIEW_DIFF);
+                       const char *diff_index_argv[] = {
+                               "git", "diff-index", "--root", "--cached",
+                                       "--patch-with-stat", "-C", "-M",
+                                       "HEAD", "--", view->vid, NULL
+                       };
+
+                       if (!prepare_update(diff, diff_index_argv, NULL, FORMAT_DASH)) {
+                               report("Failed to allocate diff command");
                                break;
-                       string_format(opt_cmd, "git diff-index --root --patch-with-stat -C -M --cached HEAD -- %s 2>/dev/null", path);
+                       }
+                       flags |= OPEN_PREPARED;
                }
 
                open_view(view, REQ_VIEW_DIFF, flags);
@@ -3767,6 +4144,7 @@ blame_select(struct view *view, struct line *line)
 
 static struct view_ops blame_ops = {
        "line",
+       NULL,
        blame_open,
        blame_read,
        blame_draw,
@@ -3796,20 +4174,29 @@ struct status {
 static char status_onbranch[SIZEOF_STR];
 static struct status stage_status;
 static enum line_type stage_line_type;
+static size_t stage_chunks;
+static int *stage_chunk;
+
+/* This should work even for the "On branch" line. */
+static inline bool
+status_has_none(struct view *view, struct line *line)
+{
+       return line < view->line + view->lines && !line[1].data;
+}
 
 /* Get fields from the diff line:
  * :100644 100644 06a5d6ae9eca55be2e0e585a152e6b1336f2b20e 0000000000000000000000000000000000000000 M
  */
 static inline bool
-status_get_diff(struct status *file, char *buf, size_t bufsize)
+status_get_diff(struct status *file, const char *buf, size_t bufsize)
 {
-       char *old_mode = buf +  1;
-       char *new_mode = buf +  8;
-       char *old_rev  = buf + 15;
-       char *new_rev  = buf + 56;
-       char *status   = buf + 97;
+       const char *old_mode = buf +  1;
+       const char *new_mode = buf +  8;
+       const char *old_rev  = buf + 15;
+       const char *new_rev  = buf + 56;
+       const char *status   = buf + 97;
 
-       if (bufsize < 99 ||
+       if (bufsize < 98 ||
            old_mode[-1] != ':' ||
            new_mode[-1] != ' ' ||
            old_rev[-1]  != ' ' ||
@@ -3831,135 +4218,109 @@ status_get_diff(struct status *file, char *buf, size_t bufsize)
 }
 
 static bool
-status_run(struct view *view, const char cmd[], char status, enum line_type type)
+status_run(struct view *view, const char *argv[], char status, enum line_type type)
 {
        struct status *file = NULL;
        struct status *unmerged = NULL;
-       char buf[SIZEOF_STR * 4];
-       size_t bufsize = 0;
-       FILE *pipe;
+       char *buf;
+       struct io io = {};
 
-       pipe = popen(cmd, "r");
-       if (!pipe)
+       if (!run_io(&io, argv, NULL, IO_RD))
                return FALSE;
 
        add_line_data(view, NULL, type);
 
-       while (!feof(pipe) && !ferror(pipe)) {
-               char *sep;
-               size_t readsize;
+       while ((buf = io_get(&io, 0, TRUE))) {
+               if (!file) {
+                       file = calloc(1, sizeof(*file));
+                       if (!file || !add_line_data(view, file, type))
+                               goto error_out;
+               }
 
-               readsize = fread(buf + bufsize, 1, sizeof(buf) - bufsize, pipe);
-               if (!readsize)
-                       break;
-               bufsize += readsize;
+               /* Parse diff info part. */
+               if (status) {
+                       file->status = status;
+                       if (status == 'A')
+                               string_copy(file->old.rev, NULL_ID);
 
-               /* Process while we have NUL chars. */
-               while ((sep = memchr(buf, 0, bufsize))) {
-                       size_t sepsize = sep - buf + 1;
+               } else if (!file->status) {
+                       if (!status_get_diff(file, buf, strlen(buf)))
+                               goto error_out;
 
-                       if (!file) {
-                               if (!realloc_lines(view, view->line_size + 1))
-                                       goto error_out;
+                       buf = io_get(&io, 0, TRUE);
+                       if (!buf)
+                               break;
 
-                               file = calloc(1, sizeof(*file));
-                               if (!file)
-                                       goto error_out;
+                       /* Collapse all 'M'odified entries that follow a
+                        * associated 'U'nmerged entry. */
+                       if (file->status == 'U') {
+                               unmerged = file;
 
-                               add_line_data(view, file, type);
-                       }
+                       } else if (unmerged) {
+                               int collapse = !strcmp(buf, unmerged->new.name);
 
-                       /* Parse diff info part. */
-                       if (status) {
-                               file->status = status;
-                               if (status == 'A')
-                                       string_copy(file->old.rev, NULL_ID);
-
-                       } else if (!file->status) {
-                               if (!status_get_diff(file, buf, sepsize))
-                                       goto error_out;
-
-                               bufsize -= sepsize;
-                               memmove(buf, sep + 1, bufsize);
-
-                               sep = memchr(buf, 0, bufsize);
-                               if (!sep)
-                                       break;
-                               sepsize = sep - buf + 1;
-
-                               /* Collapse all 'M'odified entries that
-                                * follow a associated 'U'nmerged entry.
-                                */
-                               if (file->status == 'U') {
-                                       unmerged = file;
-
-                               } else if (unmerged) {
-                                       int collapse = !strcmp(buf, unmerged->new.name);
-
-                                       unmerged = NULL;
-                                       if (collapse) {
-                                               free(file);
-                                               view->lines--;
-                                               continue;
-                                       }
+                               unmerged = NULL;
+                               if (collapse) {
+                                       free(file);
+                                       view->lines--;
+                                       continue;
                                }
                        }
+               }
 
-                       /* Grab the old name for rename/copy. */
-                       if (!*file->old.name &&
-                           (file->status == 'R' || file->status == 'C')) {
-                               sepsize = sep - buf + 1;
-                               string_ncopy(file->old.name, buf, sepsize);
-                               bufsize -= sepsize;
-                               memmove(buf, sep + 1, bufsize);
-
-                               sep = memchr(buf, 0, bufsize);
-                               if (!sep)
-                                       break;
-                               sepsize = sep - buf + 1;
-                       }
+               /* Grab the old name for rename/copy. */
+               if (!*file->old.name &&
+                   (file->status == 'R' || file->status == 'C')) {
+                       string_ncopy(file->old.name, buf, strlen(buf));
 
-                       /* git-ls-files just delivers a NUL separated
-                        * list of file names similar to the second half
-                        * of the git-diff-* output. */
-                       string_ncopy(file->new.name, buf, sepsize);
-                       if (!*file->old.name)
-                               string_copy(file->old.name, file->new.name);
-                       bufsize -= sepsize;
-                       memmove(buf, sep + 1, bufsize);
-                       file = NULL;
+                       buf = io_get(&io, 0, TRUE);
+                       if (!buf)
+                               break;
                }
+
+               /* git-ls-files just delivers a NUL separated list of
+                * file names similar to the second half of the
+                * git-diff-* output. */
+               string_ncopy(file->new.name, buf, strlen(buf));
+               if (!*file->old.name)
+                       string_copy(file->old.name, file->new.name);
+               file = NULL;
        }
 
-       if (ferror(pipe)) {
+       if (io_error(&io)) {
 error_out:
-               pclose(pipe);
+               done_io(&io);
                return FALSE;
        }
 
        if (!view->line[view->lines - 1].data)
                add_line_data(view, NULL, LINE_STAT_NONE);
 
-       pclose(pipe);
+       done_io(&io);
        return TRUE;
 }
 
 /* Don't show unmerged entries in the staged section. */
-#define STATUS_DIFF_INDEX_CMD "git diff-index -z --diff-filter=ACDMRTXB --cached -M HEAD"
-#define STATUS_DIFF_FILES_CMD "git diff-files -z"
-#define STATUS_LIST_OTHER_CMD \
-       "git ls-files -z --others --exclude-per-directory=.gitignore"
-#define STATUS_LIST_NO_HEAD_CMD \
-       "git ls-files -z --cached --exclude-per-directory=.gitignore"
+static const char *status_diff_index_argv[] = {
+       "git", "diff-index", "-z", "--diff-filter=ACDMRTXB",
+                            "--cached", "-M", "HEAD", NULL
+};
+
+static const char *status_diff_files_argv[] = {
+       "git", "diff-files", "-z", NULL
+};
 
-#define STATUS_DIFF_INDEX_SHOW_CMD \
-       "git diff-index --root --patch-with-stat -C -M --cached HEAD -- %s %s 2>/dev/null"
+static const char *status_list_other_argv[] = {
+       "git", "ls-files", "-z", "--others", "--exclude-standard", NULL
+};
 
-#define STATUS_DIFF_FILES_SHOW_CMD \
-       "git diff-files --root --patch-with-stat -C -M -- %s %s 2>/dev/null"
+static const char *status_list_no_head_argv[] = {
+       "git", "ls-files", "-z", "--cached", "--exclude-standard", NULL
+};
 
-#define STATUS_DIFF_NO_HEAD_SHOW_CMD \
-       "git diff --no-color --patch-with-stat /dev/null %s 2>/dev/null"
+static const char *update_index_argv[] = {
+       "git", "update-index", "-q", "--unmerged", "--refresh", NULL
+};
 
 /* First parse staged info using git-diff-index(1), then parse unstaged
  * info using git-diff-files(1), and finally untracked files using
@@ -3967,58 +4328,29 @@ error_out:
 static bool
 status_open(struct view *view)
 {
-       struct stat statbuf;
-       char exclude[SIZEOF_STR];
-       char indexcmd[SIZEOF_STR] = STATUS_DIFF_INDEX_CMD;
-       char othercmd[SIZEOF_STR] = STATUS_LIST_OTHER_CMD;
        unsigned long prev_lineno = view->lineno;
-       char indexstatus = 0;
-       size_t i;
-
-       for (i = 0; i < view->lines; i++)
-               free(view->line[i].data);
-       free(view->line);
-       view->lines = view->line_alloc = view->line_size = view->lineno = 0;
-       view->line = NULL;
 
-       if (!realloc_lines(view, view->line_size + 7))
-               return FALSE;
+       reset_view(view);
 
        add_line_data(view, NULL, LINE_STAT_HEAD);
-       if (opt_no_head)
+       if (is_initial_commit())
                string_copy(status_onbranch, "Initial commit");
        else if (!*opt_head)
                string_copy(status_onbranch, "Not currently on any branch");
        else if (!string_format(status_onbranch, "On branch %s", opt_head))
                return FALSE;
 
-       if (opt_no_head) {
-               string_copy(indexcmd, STATUS_LIST_NO_HEAD_CMD);
-               indexstatus = 'A';
-       }
-
-       if (!string_format(exclude, "%s/info/exclude", opt_git_dir))
-               return FALSE;
-
-       if (stat(exclude, &statbuf) >= 0) {
-               size_t cmdsize = strlen(othercmd);
-
-               if (!string_format_from(othercmd, &cmdsize, " %s", "--exclude-from=") ||
-                   sq_quote(othercmd, cmdsize, exclude) >= sizeof(othercmd))
-                       return FALSE;
+       run_io_bg(update_index_argv);
 
-               cmdsize = strlen(indexcmd);
-               if (opt_no_head &&
-                   (!string_format_from(indexcmd, &cmdsize, " %s", "--exclude-from=") ||
-                    sq_quote(indexcmd, cmdsize, exclude) >= sizeof(indexcmd)))
+       if (is_initial_commit()) {
+               if (!status_run(view, status_list_no_head_argv, 'A', LINE_STAT_STAGED))
                        return FALSE;
+       } else if (!status_run(view, status_diff_index_argv, 0, LINE_STAT_STAGED)) {
+               return FALSE;
        }
 
-       system("git update-index -q --refresh >/dev/null 2>/dev/null");
-
-       if (!status_run(view, indexcmd, indexstatus, LINE_STAT_STAGED) ||
-           !status_run(view, STATUS_DIFF_FILES_CMD, 0, LINE_STAT_UNSTAGED) ||
-           !status_run(view, othercmd, '?', LINE_STAT_UNTRACKED))
+       if (!status_run(view, status_diff_files_argv, 0, LINE_STAT_UNSTAGED) ||
+           !status_run(view, status_list_other_argv, '?', LINE_STAT_UNTRACKED))
                return FALSE;
 
        /* If all went well restore the previous line number to stay in
@@ -4050,7 +4382,7 @@ status_draw(struct view *view, struct line *line, unsigned int lineno)
 {
        struct status *status = line->data;
        enum line_type type;
-       char *text;
+       const char *text;
 
        if (!status) {
                switch (line->type) {
@@ -4100,11 +4432,13 @@ static enum request
 status_enter(struct view *view, struct line *line)
 {
        struct status *status = line->data;
-       char oldpath[SIZEOF_STR] = "";
-       char newpath[SIZEOF_STR] = "";
-       char *info;
-       size_t cmdsize = 0;
+       const char *oldpath = status ? status->old.name : NULL;
+       /* Diffs for unmerged entries are empty when passing the new
+        * path, so leave it empty. */
+       const char *newpath = status && status->status != 'U' ? status->new.name : NULL;
+       const char *info;
        enum open_flags split;
+       struct view *stage = VIEW(REQ_VIEW_STAGE);
 
        if (line->type == LINE_STAT_NONE ||
            (!status && line[1].type == LINE_STAT_NONE)) {
@@ -4112,32 +4446,24 @@ status_enter(struct view *view, struct line *line)
                return REQ_NONE;
        }
 
-       if (status) {
-               if (sq_quote(oldpath, 0, status->old.name) >= sizeof(oldpath))
-                       return REQ_QUIT;
-               /* Diffs for unmerged entries are empty when pasing the
-                * new path, so leave it empty. */
-               if (status->status != 'U' &&
-                   sq_quote(newpath, 0, status->new.name) >= sizeof(newpath))
-                       return REQ_QUIT;
-       }
-
-       if (opt_cdup[0] &&
-           line->type != LINE_STAT_UNTRACKED &&
-           !string_format_from(opt_cmd, &cmdsize, "cd %s;", opt_cdup))
-               return REQ_QUIT;
-
        switch (line->type) {
        case LINE_STAT_STAGED:
-               if (opt_no_head) {
-                       if (!string_format_from(opt_cmd, &cmdsize,
-                                               STATUS_DIFF_NO_HEAD_SHOW_CMD,
-                                               newpath))
+               if (is_initial_commit()) {
+                       const char *no_head_diff_argv[] = {
+                               "git", "diff", "--no-color", "--patch-with-stat",
+                                       "--", "/dev/null", newpath, NULL
+                       };
+
+                       if (!prepare_update(stage, no_head_diff_argv, opt_cdup, FORMAT_DASH))
                                return REQ_QUIT;
                } else {
-                       if (!string_format_from(opt_cmd, &cmdsize,
-                                               STATUS_DIFF_INDEX_SHOW_CMD,
-                                               oldpath, newpath))
+                       const char *index_show_argv[] = {
+                               "git", "diff-index", "--root", "--patch-with-stat",
+                                       "-C", "-M", "--cached", "HEAD", "--",
+                                       oldpath, newpath, NULL
+                       };
+
+                       if (!prepare_update(stage, index_show_argv, opt_cdup, FORMAT_DASH))
                                return REQ_QUIT;
                }
 
@@ -4148,25 +4474,33 @@ status_enter(struct view *view, struct line *line)
                break;
 
        case LINE_STAT_UNSTAGED:
-               if (!string_format_from(opt_cmd, &cmdsize,
-                                       STATUS_DIFF_FILES_SHOW_CMD, oldpath, newpath))
+       {
+               const char *files_show_argv[] = {
+                       "git", "diff-files", "--root", "--patch-with-stat",
+                               "-C", "-M", "--", oldpath, newpath, NULL
+               };
+
+               if (!prepare_update(stage, files_show_argv, opt_cdup, FORMAT_DASH))
                        return REQ_QUIT;
                if (status)
                        info = "Unstaged changes to %s";
                else
                        info = "Unstaged changes";
                break;
-
+       }
        case LINE_STAT_UNTRACKED:
-               if (opt_pipe)
-                       return REQ_QUIT;
-
-               if (!status) {
+               if (!newpath) {
                        report("No file to show");
                        return REQ_NONE;
                }
 
-               opt_pipe = fopen(status->new.name, "r");
+               if (!suffixcmp(status->new.name, -1, "/")) {
+                       report("Cannot display a directory");
+                       return REQ_NONE;
+               }
+
+               if (!prepare_update_file(stage, newpath))
+                       return REQ_QUIT;
                info = "Untracked file %s";
                break;
 
@@ -4178,7 +4512,7 @@ status_enter(struct view *view, struct line *line)
        }
 
        split = view_is_displayed(view) ? OPEN_SPLIT : 0;
-       open_view(view, REQ_VIEW_STAGE, OPEN_RELOAD | split);
+       open_view(view, REQ_VIEW_STAGE, OPEN_REFRESH | split);
        if (view_is_displayed(VIEW(REQ_VIEW_STAGE))) {
                if (status) {
                        stage_status = *status;
@@ -4187,6 +4521,7 @@ status_enter(struct view *view, struct line *line)
                }
 
                stage_line_type = line->type;
+               stage_chunks = 0;
                string_format(VIEW(REQ_VIEW_STAGE)->ref, info, stage_status.new.name);
        }
 
@@ -4211,40 +4546,37 @@ status_exists(struct status *status, enum line_type type)
 }
 
 
-static FILE *
-status_update_prepare(enum line_type type)
+static bool
+status_update_prepare(struct io *io, enum line_type type)
 {
-       char cmd[SIZEOF_STR];
-       size_t cmdsize = 0;
-
-       if (opt_cdup[0] &&
-           type != LINE_STAT_UNTRACKED &&
-           !string_format_from(cmd, &cmdsize, "cd %s;", opt_cdup))
-               return NULL;
+       const char *staged_argv[] = {
+               "git", "update-index", "-z", "--index-info", NULL
+       };
+       const char *others_argv[] = {
+               "git", "update-index", "-z", "--add", "--remove", "--stdin", NULL
+       };
 
        switch (type) {
        case LINE_STAT_STAGED:
-               string_add(cmd, cmdsize, "git update-index -z --index-info");
-               break;
+               return run_io(io, staged_argv, opt_cdup, IO_WR);
 
        case LINE_STAT_UNSTAGED:
+               return run_io(io, others_argv, opt_cdup, IO_WR);
+
        case LINE_STAT_UNTRACKED:
-               string_add(cmd, cmdsize, "git update-index -z --add --remove --stdin");
-               break;
+               return run_io(io, others_argv, NULL, IO_WR);
 
        default:
                die("line type %d not handled in switch", type);
+               return FALSE;
        }
-
-       return popen(cmd, "w");
 }
 
 static bool
-status_update_write(FILE *pipe, struct status *status, enum line_type type)
+status_update_write(struct io *io, struct status *status, enum line_type type)
 {
        char buf[SIZEOF_STR];
        size_t bufsize = 0;
-       size_t written = 0;
 
        switch (type) {
        case LINE_STAT_STAGED:
@@ -4265,37 +4597,33 @@ status_update_write(FILE *pipe, struct status *status, enum line_type type)
                die("line type %d not handled in switch", type);
        }
 
-       while (!ferror(pipe) && written < bufsize) {
-               written += fwrite(buf + written, 1, bufsize - written, pipe);
-       }
-
-       return written == bufsize;
+       return io_write(io, buf, bufsize);
 }
 
 static bool
 status_update_file(struct status *status, enum line_type type)
 {
-       FILE *pipe = status_update_prepare(type);
+       struct io io = {};
        bool result;
 
-       if (!pipe)
+       if (!status_update_prepare(&io, type))
                return FALSE;
 
-       result = status_update_write(pipe, status, type);
-       pclose(pipe);
+       result = status_update_write(&io, status, type);
+       done_io(&io);
        return result;
 }
 
 static bool
 status_update_files(struct view *view, struct line *line)
 {
-       FILE *pipe = status_update_prepare(line->type);
+       struct io io = {};
        bool result = TRUE;
        struct line *pos = view->line + view->lines;
        int files = 0;
        int file, done;
 
-       if (!pipe)
+       if (!status_update_prepare(&io, line->type))
                return FALSE;
 
        for (pos = line; pos < view->line + view->lines && pos->data; pos++)
@@ -4310,10 +4638,10 @@ status_update_files(struct view *view, struct line *line)
                                      file, files, done);
                        update_view_title(view);
                }
-               result = status_update_write(pipe, line->data, line->type);
+               result = status_update_write(&io, line->data, line->type);
        }
 
-       pclose(pipe);
+       done_io(&io);
        return result;
 }
 
@@ -4344,6 +4672,32 @@ status_update(struct view *view)
        return TRUE;
 }
 
+static bool
+status_revert(struct status *status, enum line_type type, bool has_none)
+{
+       if (!status || type != LINE_STAT_UNSTAGED) {
+               if (type == LINE_STAT_STAGED) {
+                       report("Cannot revert changes to staged files");
+               } else if (type == LINE_STAT_UNTRACKED) {
+                       report("Cannot revert changes to untracked files");
+               } else if (has_none) {
+                       report("Nothing to revert");
+               } else {
+                       report("Cannot revert changes to multiple files");
+               }
+               return FALSE;
+
+       } else {
+               const char *checkout_argv[] = {
+                       "git", "checkout", "--", status->old.name, NULL
+               };
+
+               if (!prompt_yesno("Are you sure you want to overwrite any changes?"))
+                       return FALSE;
+               return run_io_fg(checkout_argv, opt_cdup);
+       }
+}
+
 static enum request
 status_request(struct view *view, enum request request, struct line *line)
 {
@@ -4355,6 +4709,11 @@ status_request(struct view *view, enum request request, struct line *line)
                        return REQ_NONE;
                break;
 
+       case REQ_STATUS_REVERT:
+               if (!status_revert(status, line->type, status_has_none(view, line)))
+                       return REQ_NONE;
+               break;
+
        case REQ_STATUS_MERGE:
                if (!status || status->status != 'U') {
                        report("Merging only possible for files with unmerged status ('U').");
@@ -4366,6 +4725,10 @@ status_request(struct view *view, enum request request, struct line *line)
        case REQ_EDIT:
                if (!status)
                        return request;
+               if (status->status == 'D') {
+                       report("File has been deleted.");
+                       return REQ_NONE;
+               }
 
                open_editor(status->status != '?', status->new.name);
                break;
@@ -4402,8 +4765,8 @@ status_select(struct view *view, struct line *line)
 {
        struct status *status = line->data;
        char file[SIZEOF_STR] = "all files";
-       char *text;
-       char *key;
+       const char *text;
+       const char *key;
 
        if (status && !string_format(file, "'%s'", status->new.name))
                return;
@@ -4456,7 +4819,7 @@ status_grep(struct view *view, struct line *line)
                return FALSE;
 
        for (state = S_STATUS; state < S_END; state++) {
-               char *text;
+               const char *text;
 
                switch (state) {
                case S_NAME:    text = status->new.name;        break;
@@ -4478,6 +4841,7 @@ status_grep(struct view *view, struct line *line)
 
 static struct view_ops status_ops = {
        "file",
+       NULL,
        status_open,
        NULL,
        status_draw,
@@ -4488,27 +4852,13 @@ static struct view_ops status_ops = {
 
 
 static bool
-stage_diff_line(FILE *pipe, struct line *line)
-{
-       char *buf = line->data;
-       size_t bufsize = strlen(buf);
-       size_t written = 0;
-
-       while (!ferror(pipe) && written < bufsize) {
-               written += fwrite(buf + written, 1, bufsize - written, pipe);
-       }
-
-       fputc('\n', pipe);
-
-       return written == bufsize;
-}
-
-static bool
-stage_diff_write(FILE *pipe, struct line *line, struct line *end)
+stage_diff_write(struct io *io, struct line *line, struct line *end)
 {
        while (line < end) {
-               if (!stage_diff_line(pipe, line++))
+               if (!io_write(io, line->data, strlen(line->data)) ||
+                   !io_write(io, "\n", 1))
                        return FALSE;
+               line++;
                if (line->type == LINE_DIFF_CHUNK ||
                    line->type == LINE_DIFF_HEADER)
                        break;
@@ -4528,36 +4878,34 @@ stage_diff_find(struct view *view, struct line *line, enum line_type type)
 }
 
 static bool
-stage_update_chunk(struct view *view, struct line *chunk)
+stage_apply_chunk(struct view *view, struct line *chunk, bool revert)
 {
-       char cmd[SIZEOF_STR];
-       size_t cmdsize = 0;
+       const char *apply_argv[SIZEOF_ARG] = {
+               "git", "apply", "--whitespace=nowarn", NULL
+       };
        struct line *diff_hdr;
-       FILE *pipe;
+       struct io io = {};
+       int argc = 3;
 
        diff_hdr = stage_diff_find(view, chunk, LINE_DIFF_HEADER);
        if (!diff_hdr)
                return FALSE;
 
-       if (opt_cdup[0] &&
-           !string_format_from(cmd, &cmdsize, "cd %s;", opt_cdup))
+       if (!revert)
+               apply_argv[argc++] = "--cached";
+       if (revert || stage_line_type == LINE_STAT_STAGED)
+               apply_argv[argc++] = "-R";
+       apply_argv[argc++] = "-";
+       apply_argv[argc++] = NULL;
+       if (!run_io(&io, apply_argv, opt_cdup, IO_WR))
                return FALSE;
 
-       if (!string_format_from(cmd, &cmdsize,
-                               "git apply --whitespace=nowarn --cached %s - && "
-                               "git update-index -q --unmerged --refresh 2>/dev/null",
-                               stage_line_type == LINE_STAT_STAGED ? "-R" : ""))
-               return FALSE;
-
-       pipe = popen(cmd, "w");
-       if (!pipe)
-               return FALSE;
-
-       if (!stage_diff_write(pipe, diff_hdr, chunk) ||
-           !stage_diff_write(pipe, chunk, view->line + view->lines))
+       if (!stage_diff_write(&io, diff_hdr, chunk) ||
+           !stage_diff_write(&io, chunk, view->line + view->lines))
                chunk = NULL;
 
-       pclose(pipe);
+       done_io(&io);
+       run_io_bg(update_index_argv);
 
        return chunk ? TRUE : FALSE;
 }
@@ -4567,11 +4915,11 @@ stage_update(struct view *view, struct line *line)
 {
        struct line *chunk = NULL;
 
-       if (!opt_no_head && stage_line_type != LINE_STAT_UNTRACKED)
+       if (!is_initial_commit() && stage_line_type != LINE_STAT_UNTRACKED)
                chunk = stage_diff_find(view, line, LINE_DIFF_CHUNK);
 
        if (chunk) {
-               if (!stage_update_chunk(view, chunk)) {
+               if (!stage_apply_chunk(view, chunk, FALSE)) {
                        report("Failed to apply chunk");
                        return FALSE;
                }
@@ -4596,6 +4944,67 @@ stage_update(struct view *view, struct line *line)
        return TRUE;
 }
 
+static bool
+stage_revert(struct view *view, struct line *line)
+{
+       struct line *chunk = NULL;
+
+       if (!is_initial_commit() && stage_line_type == LINE_STAT_UNSTAGED)
+               chunk = stage_diff_find(view, line, LINE_DIFF_CHUNK);
+
+       if (chunk) {
+               if (!prompt_yesno("Are you sure you want to revert changes?"))
+                       return FALSE;
+
+               if (!stage_apply_chunk(view, chunk, TRUE)) {
+                       report("Failed to revert chunk");
+                       return FALSE;
+               }
+               return TRUE;
+
+       } else {
+               return status_revert(stage_status.status ? &stage_status : NULL,
+                                    stage_line_type, FALSE);
+       }
+}
+
+
+static void
+stage_next(struct view *view, struct line *line)
+{
+       int i;
+
+       if (!stage_chunks) {
+               static size_t alloc = 0;
+               int *tmp;
+
+               for (line = view->line; line < view->line + view->lines; line++) {
+                       if (line->type != LINE_DIFF_CHUNK)
+                               continue;
+
+                       tmp = realloc_items(stage_chunk, &alloc,
+                                           stage_chunks, sizeof(*tmp));
+                       if (!tmp) {
+                               report("Allocation failure");
+                               return;
+                       }
+
+                       stage_chunk = tmp;
+                       stage_chunk[stage_chunks++] = line - view->line;
+               }
+       }
+
+       for (i = 0; i < stage_chunks; i++) {
+               if (stage_chunk[i] > view->lineno) {
+                       do_scroll_view(view, stage_chunk[i] - view->lineno);
+                       report("Chunk %d of %d", i + 1, stage_chunks);
+                       return;
+               }
+       }
+
+       report("No next chunk found");
+}
+
 static enum request
 stage_request(struct view *view, enum request request, struct line *line)
 {
@@ -4605,9 +5014,27 @@ stage_request(struct view *view, enum request request, struct line *line)
                        return REQ_NONE;
                break;
 
+       case REQ_STATUS_REVERT:
+               if (!stage_revert(view, line))
+                       return REQ_NONE;
+               break;
+
+       case REQ_STAGE_NEXT:
+               if (stage_line_type == LINE_STAT_UNTRACKED) {
+                       report("File is untracked; press %s to add",
+                              get_key(REQ_STATUS_UPDATE));
+                       return REQ_NONE;
+               }
+               stage_next(view, line);
+               return REQ_NONE;
+
        case REQ_EDIT:
                if (!stage_status.new.name[0])
                        return request;
+               if (stage_status.status == 'D') {
+                       report("File has been deleted.");
+                       return REQ_NONE;
+               }
 
                open_editor(stage_status.status != '?', stage_status.new.name);
                break;
@@ -4637,11 +5064,18 @@ stage_request(struct view *view, enum request request, struct line *line)
        if (!status_exists(&stage_status, stage_line_type))
                return REQ_VIEW_CLOSE;
 
-       if (stage_line_type == LINE_STAT_UNTRACKED)
-               opt_pipe = fopen(stage_status.new.name, "r");
-       else
-               string_copy(opt_cmd, view->cmd);
-       open_view(view, REQ_VIEW_STAGE, OPEN_RELOAD | OPEN_NOMAXIMIZE);
+       if (stage_line_type == LINE_STAT_UNTRACKED) {
+               if (!suffixcmp(stage_status.new.name, -1, "/")) {
+                       report("Cannot display a directory");
+                       return REQ_NONE;
+               }
+
+               if (!prepare_update_file(view, stage_status.new.name)) {
+                       report("Failed to open file: %s", strerror(errno));
+                       return REQ_NONE;
+               }
+       }
+       open_view(view, REQ_VIEW_STAGE, OPEN_REFRESH);
 
        return REQ_NONE;
 }
@@ -4649,6 +5083,7 @@ stage_request(struct view *view, enum request request, struct line *line)
 static struct view_ops stage_ops = {
        "line",
        NULL,
+       NULL,
        pager_read,
        pager_draw,
        stage_request,
@@ -4710,6 +5145,15 @@ append_to_rev_graph(struct rev_graph *graph, chtype symbol)
                commit->graph[commit->graph_size++] = symbol;
 }
 
+static void
+clear_rev_graph(struct rev_graph *graph)
+{
+       graph->boundary = 0;
+       graph->size = graph->pos = 0;
+       graph->commit = NULL;
+       memset(graph->parents, 0, sizeof(*graph->parents));
+}
+
 static void
 done_rev_graph(struct rev_graph *graph)
 {
@@ -4726,13 +5170,11 @@ done_rev_graph(struct rev_graph *graph)
                }
        }
 
-       graph->size = graph->pos = 0;
-       graph->commit = NULL;
-       memset(graph->parents, 0, sizeof(*graph->parents));
+       clear_rev_graph(graph);
 }
 
 static void
-push_rev_graph(struct rev_graph *graph, char *parent)
+push_rev_graph(struct rev_graph *graph, const char *parent)
 {
        int i;
 
@@ -4850,7 +5292,7 @@ prepare_rev_graph(struct rev_graph *graph)
 }
 
 static void
-update_rev_graph(struct rev_graph *graph)
+update_rev_graph(struct view *view, struct rev_graph *graph)
 {
        /* If this is the finalizing update ... */
        if (graph->commit)
@@ -4861,6 +5303,10 @@ update_rev_graph(struct rev_graph *graph)
        if (!graph->prev->commit)
                return;
 
+       if (view->lines > 2)
+               view->line[view->lines - 3].dirty = 1;
+       if (view->lines > 1)
+               view->line[view->lines - 2].dirty = 1;
        draw_rev_graph(graph->prev);
        done_rev_graph(graph->prev->prev);
 }
@@ -4870,6 +5316,11 @@ update_rev_graph(struct rev_graph *graph)
  * Main view backend
  */
 
+static const char *main_argv[SIZEOF_ARG] = {
+       "git", "log", "--no-color", "--pretty=raw", "--parents",
+                     "--topo-order", "%(head)", NULL
+};
+
 static bool
 main_draw(struct view *view, struct line *line, unsigned int lineno)
 {
@@ -4882,7 +5333,7 @@ main_draw(struct view *view, struct line *line, unsigned int lineno)
                return TRUE;
 
        if (opt_author &&
-           draw_field(view, LINE_MAIN_AUTHOR, commit->author, AUTHOR_COLS, TRUE))
+           draw_field(view, LINE_MAIN_AUTHOR, commit->author, opt_author_cols, TRUE))
                return TRUE;
 
        if (opt_rev_graph && commit->graph_size &&
@@ -4931,9 +5382,22 @@ main_read(struct view *view, char *line)
        struct commit *commit;
 
        if (!line) {
+               int i;
+
                if (!view->lines && !view->parent)
                        die("No revisions match the given arguments.");
-               update_rev_graph(graph);
+               if (view->lines > 0) {
+                       commit = view->line[view->lines - 1].data;
+                       if (!*commit->author) {
+                               view->lines--;
+                               free(commit);
+                               graph->commit = NULL;
+                       }
+               }
+               update_rev_graph(view, graph);
+
+               for (i = 0; i < ARRAY_SIZE(graph_stacks); i++)
+                       clear_rev_graph(&graph_stacks[i]);
                return TRUE;
        }
 
@@ -4985,7 +5449,7 @@ main_read(struct view *view, char *line)
                if (!nameend || !emailend)
                        break;
 
-               update_rev_graph(graph);
+               update_rev_graph(view, graph);
                graph = graph->next;
 
                *nameend = *emailend = 0;
@@ -4997,6 +5461,7 @@ main_read(struct view *view, char *line)
                }
 
                string_ncopy(commit->author, ident, strlen(ident));
+               view->line[view->lines - 1].dirty = 1;
 
                /* Parse epoch and timezone */
                if (emailend[1] == ' ') {
@@ -5043,6 +5508,7 @@ main_read(struct view *view, char *line)
                 * shortened titles, etc. */
 
                string_ncopy(commit->title, line, strlen(line));
+               view->line[view->lines - 1].dirty = 1;
        }
 
        return TRUE;
@@ -5053,10 +5519,17 @@ main_request(struct view *view, enum request request, struct line *line)
 {
        enum open_flags flags = display[0] == view ? OPEN_SPLIT : OPEN_DEFAULT;
 
-       if (request == REQ_ENTER)
+       switch (request) {
+       case REQ_ENTER:
                open_view(view, REQ_VIEW_DIFF, flags);
-       else
+               break;
+       case REQ_REFRESH:
+               load_refs();
+               open_view(view, REQ_VIEW_MAIN, OPEN_REFRESH);
+               break;
+       default:
                return request;
+       }
 
        return REQ_NONE;
 }
@@ -5130,6 +5603,7 @@ main_select(struct view *view, struct line *line)
 
 static struct view_ops main_ops = {
        "commit",
+       main_argv,
        NULL,
        main_read,
        main_draw,
@@ -5369,13 +5843,13 @@ init_display(void)
        /* Initialize the curses library */
        if (isatty(STDIN_FILENO)) {
                cursed = !!initscr();
+               opt_tty = stdin;
        } else {
                /* Leave stdin and stdout alone when acting as a pager. */
-               FILE *io = fopen("/dev/tty", "r+");
-
-               if (!io)
+               opt_tty = fopen("/dev/tty", "r+");
+               if (!opt_tty)
                        die("Failed to open /dev/tty");
-               cursed = !!newterm(NULL, io, io);
+               cursed = !!newterm(NULL, opt_tty, opt_tty);
        }
 
        if (!cursed)
@@ -5404,11 +5878,63 @@ init_display(void)
        }
 }
 
+static bool
+prompt_yesno(const char *prompt)
+{
+       enum { WAIT, STOP, CANCEL  } status = WAIT;
+       bool answer = FALSE;
+
+       while (status == WAIT) {
+               struct view *view;
+               int i, key;
+
+               input_mode = TRUE;
+
+               foreach_view (view, i)
+                       update_view(view);
+
+               input_mode = FALSE;
+
+               mvwprintw(status_win, 0, 0, "%s [Yy]/[Nn]", prompt);
+               wclrtoeol(status_win);
+
+               /* Refresh, accept single keystroke of input */
+               key = wgetch(status_win);
+               switch (key) {
+               case ERR:
+                       break;
+
+               case 'y':
+               case 'Y':
+                       answer = TRUE;
+                       status = STOP;
+                       break;
+
+               case KEY_ESC:
+               case KEY_RETURN:
+               case KEY_ENTER:
+               case KEY_BACKSPACE:
+               case 'n':
+               case 'N':
+               case '\n':
+               default:
+                       answer = FALSE;
+                       status = CANCEL;
+               }
+       }
+
+       /* Clear the status window */
+       status_empty = FALSE;
+       report("");
+
+       return answer;
+}
+
 static char *
 read_prompt(const char *prompt)
 {
        enum { READING, STOP, CANCEL } status = READING;
-       static char buf[sizeof(opt_cmd) - STRING_SIZE("git \0")];
+       static char buf[SIZEOF_STR];
        int pos = 0;
 
        while (status == READING) {
@@ -5472,9 +5998,20 @@ read_prompt(const char *prompt)
 }
 
 /*
- * Repository references
+ * Repository properties
  */
 
+static int
+git_properties(const char **argv, const char *separators,
+              int (*read_property)(char *, size_t, char *, size_t))
+{
+       struct io io = {};
+
+       if (init_io_rd(&io, argv, NULL, FORMAT_NONE))
+               return read_properties(&io, separators, read_property);
+       return ERR;
+}
+
 static struct ref *refs = NULL;
 static size_t refs_alloc = 0;
 static size_t refs_size = 0;
@@ -5484,8 +6021,27 @@ static struct ref ***id_refs = NULL;
 static size_t id_refs_alloc = 0;
 static size_t id_refs_size = 0;
 
+static int
+compare_refs(const void *ref1_, const void *ref2_)
+{
+       const struct ref *ref1 = *(const struct ref **)ref1_;
+       const struct ref *ref2 = *(const struct ref **)ref2_;
+
+       if (ref1->tag != ref2->tag)
+               return ref2->tag - ref1->tag;
+       if (ref1->ltag != ref2->ltag)
+               return ref2->ltag - ref2->ltag;
+       if (ref1->head != ref2->head)
+               return ref2->head - ref1->head;
+       if (ref1->tracked != ref2->tracked)
+               return ref2->tracked - ref1->tracked;
+       if (ref1->remote != ref2->remote)
+               return ref2->remote - ref1->remote;
+       return strcmp(ref1->name, ref2->name);
+}
+
 static struct ref **
-get_refs(char *id)
+get_refs(const char *id)
 {
        struct ref ***tmp_id_refs;
        struct ref **ref_list = NULL;
@@ -5519,19 +6075,20 @@ get_refs(char *id)
                }
 
                ref_list = tmp;
-               if (ref_list_size > 0)
-                       ref_list[ref_list_size - 1]->next = 1;
                ref_list[ref_list_size] = &refs[i];
-
                /* XXX: The properties of the commit chains ensures that we can
                 * safely modify the shared ref. The repo references will
                 * always be similar for the same id. */
-               ref_list[ref_list_size]->next = 0;
+               ref_list[ref_list_size]->next = 1;
+
                ref_list_size++;
        }
 
-       if (ref_list)
+       if (ref_list) {
+               qsort(ref_list, ref_list_size, sizeof(*ref_list), compare_refs);
+               ref_list[ref_list_size - 1]->next = 0;
                id_refs[id_refs_size++] = ref_list;
+       }
 
        return ref_list;
 }
@@ -5547,8 +6104,8 @@ read_ref(char *id, size_t idlen, char *name, size_t namelen)
        bool check_replace = FALSE;
        bool head = FALSE;
 
-       if (!strncmp(name, "refs/tags/", STRING_SIZE("refs/tags/"))) {
-               if (!strcmp(name + namelen - 3, "^{}")) {
+       if (!prefixcmp(name, "refs/tags/")) {
+               if (!suffixcmp(name, namelen, "^{}")) {
                        namelen -= 3;
                        name[namelen] = 0;
                        if (refs_size > 0 && refs[refs_size - 1].ltag == TRUE)
@@ -5561,26 +6118,26 @@ read_ref(char *id, size_t idlen, char *name, size_t namelen)
                namelen -= STRING_SIZE("refs/tags/");
                name    += STRING_SIZE("refs/tags/");
 
-       } else if (!strncmp(name, "refs/remotes/", STRING_SIZE("refs/remotes/"))) {
+       } else if (!prefixcmp(name, "refs/remotes/")) {
                remote = TRUE;
                namelen -= STRING_SIZE("refs/remotes/");
                name    += STRING_SIZE("refs/remotes/");
                tracked  = !strcmp(opt_remote, name);
 
-       } else if (!strncmp(name, "refs/heads/", STRING_SIZE("refs/heads/"))) {
+       } else if (!prefixcmp(name, "refs/heads/")) {
                namelen -= STRING_SIZE("refs/heads/");
                name    += STRING_SIZE("refs/heads/");
                head     = !strncmp(opt_head, name, namelen);
 
        } else if (!strcmp(name, "HEAD")) {
-               opt_no_head = FALSE;
+               string_ncopy(opt_head_rev, id, idlen);
                return OK;
        }
 
        if (check_replace && !strcmp(name, refs[refs_size - 1].name)) {
                /* it's an annotated tag, replace the previous sha1 with the
                 * resolved commit id; relies on the fact git-ls-remote lists
-                * the commit id of an annotated tag right beofre the commit id
+                * the commit id of an annotated tag right before the commit id
                 * it points to. */
                refs[refs_size - 1].ltag = ltag;
                string_copy_rev(refs[refs_size - 1].id, id);
@@ -5611,10 +6168,25 @@ read_ref(char *id, size_t idlen, char *name, size_t namelen)
 static int
 load_refs(void)
 {
-       const char *cmd_env = getenv("TIG_LS_REMOTE");
-       const char *cmd = cmd_env && *cmd_env ? cmd_env : TIG_LS_REMOTE;
+       static const char *ls_remote_argv[SIZEOF_ARG] = {
+               "git", "ls-remote", ".", NULL
+       };
+       static bool init = FALSE;
+
+       if (!init) {
+               argv_from_env(ls_remote_argv, "TIG_LS_REMOTE");
+               init = TRUE;
+       }
+
+       if (!*opt_git_dir)
+               return OK;
+
+       while (refs_size > 0)
+               free(refs[--refs_size].name);
+       while (id_refs_size > 0)
+               free(id_refs[--id_refs_size]);
 
-       return read_properties(popen(cmd, "r"), "\t", read_ref);
+       return git_properties(ls_remote_argv, "\t", read_ref);
 }
 
 static int
@@ -5639,7 +6211,7 @@ read_repo_config_option(char *name, size_t namelen, char *value, size_t valuelen
            !strcmp(name + 7 + strlen(opt_head), ".merge")) {
                size_t from = strlen(opt_remote);
 
-               if (!strncmp(value, "refs/heads/", STRING_SIZE("refs/heads/"))) {
+               if (!prefixcmp(value, "refs/heads/")) {
                        value += STRING_SIZE("refs/heads/");
                        valuelen -= STRING_SIZE("refs/heads/");
                }
@@ -5654,8 +6226,9 @@ read_repo_config_option(char *name, size_t namelen, char *value, size_t valuelen
 static int
 load_git_config(void)
 {
-       return read_properties(popen(GIT_CONFIG " --list", "r"),
-                              "=", read_repo_config_option);
+       const char *config_list_argv[] = { "git", GIT_CONFIG, "--list", NULL };
+
+       return git_properties(config_list_argv, "=", read_repo_config_option);
 }
 
 static int
@@ -5671,15 +6244,8 @@ read_repo_info(char *name, size_t namelen, char *value, size_t valuelen)
                 * the option else either "true" or "false" is printed.
                 * Default to true for the unknown case. */
                opt_is_inside_work_tree = strcmp(name, "false") ? TRUE : FALSE;
-
-       } else if (opt_cdup[0] == ' ') {
-               string_ncopy(opt_cdup, name, namelen);
        } else {
-               if (!strncmp(name, "refs/heads/", STRING_SIZE("refs/heads/"))) {
-                       namelen -= STRING_SIZE("refs/heads/");
-                       name    += STRING_SIZE("refs/heads/");
-                       string_ncopy(opt_head, name, namelen);
-               }
+               string_ncopy(opt_cdup, name, namelen);
        }
 
        return OK;
@@ -5688,34 +6254,37 @@ read_repo_info(char *name, size_t namelen, char *value, size_t valuelen)
 static int
 load_repo_info(void)
 {
-       int result;
-       FILE *pipe = popen("(git rev-parse --git-dir --is-inside-work-tree "
-                          " --show-cdup; git symbolic-ref HEAD) 2>/dev/null", "r");
+       const char *head_argv[] = {
+               "git", "symbolic-ref", "HEAD", NULL
+       };
+       const char *rev_parse_argv[] = {
+               "git", "rev-parse", "--git-dir", "--is-inside-work-tree",
+                       "--show-cdup", NULL
+       };
 
-       /* XXX: The line outputted by "--show-cdup" can be empty so
-        * initialize it to something invalid to make it possible to
-        * detect whether it has been set or not. */
-       opt_cdup[0] = ' ';
+       if (run_io_buf(head_argv, opt_head, sizeof(opt_head))) {
+               chomp_string(opt_head);
+               if (!prefixcmp(opt_head, "refs/heads/")) {
+                       char *offset = opt_head + STRING_SIZE("refs/heads/");
 
-       result = read_properties(pipe, "=", read_repo_info);
-       if (opt_cdup[0] == ' ')
-               opt_cdup[0] = 0;
+                       memmove(opt_head, offset, strlen(offset) + 1);
+               }
+       }
 
-       return result;
+       return git_properties(rev_parse_argv, "=", read_repo_info);
 }
 
 static int
-read_properties(FILE *pipe, const char *separators,
+read_properties(struct io *io, const char *separators,
                int (*read_property)(char *, size_t, char *, size_t))
 {
-       char buffer[BUFSIZ];
        char *name;
        int state = OK;
 
-       if (!pipe)
+       if (!start_io(io))
                return ERR;
 
-       while (state == OK && (name = fgets(buffer, sizeof(buffer), pipe))) {
+       while (state == OK && (name = io_get(io, '\n', TRUE))) {
                char *value;
                size_t namelen;
                size_t valuelen;
@@ -5736,10 +6305,9 @@ read_properties(FILE *pipe, const char *separators,
                state = read_property(name, namelen, value, valuelen);
        }
 
-       if (state != ERR && ferror(pipe))
+       if (state != ERR && io_error(io))
                state = ERR;
-
-       pclose(pipe);
+       done_io(io);
 
        return state;
 }
@@ -5787,8 +6355,9 @@ warn(const char *msg, ...)
 }
 
 int
-main(int argc, char *argv[])
+main(int argc, const char *argv[])
 {
+       const char **run_argv = NULL;
        struct view *view;
        enum request request;
        size_t i;
@@ -5810,11 +6379,12 @@ main(int argc, char *argv[])
        if (load_git_config() == ERR)
                die("Failed to load repo config.");
 
-       if (!parse_options(argc, argv))
+       request = parse_options(argc, argv, &run_argv);
+       if (request == REQ_NONE)
                return 0;
 
        /* Require a git repository unless when running in pager mode. */
-       if (!opt_git_dir[0] && opt_request != REQ_VIEW_PAGER)
+       if (!opt_git_dir[0] && request != REQ_VIEW_PAGER)
                die("Not a git repository");
 
        if (*opt_encoding && strcasecmp(opt_encoding, "UTF-8"))
@@ -5826,22 +6396,30 @@ main(int argc, char *argv[])
                        die("Failed to initialize character set conversion");
        }
 
-       if (*opt_git_dir && load_refs() == ERR)
+       if (load_refs() == ERR)
                die("Failed to load refs.");
 
-       for (i = 0; i < ARRAY_SIZE(views) && (view = &views[i]); i++)
-               view->cmd_env = getenv(view->cmd_env);
-
-       request = opt_request;
+       foreach_view (view, i)
+               argv_from_env(view->ops->argv, view->cmd_env);
 
        init_display();
 
+       if (request == REQ_VIEW_PAGER || run_argv) {
+               if (request == REQ_VIEW_PAGER)
+                       io_open(&VIEW(request)->io, "");
+               else if (!prepare_update(VIEW(request), run_argv, NULL, FORMAT_NONE))
+                       die("Failed to format arguments");
+               open_view(NULL, request, OPEN_PREPARED);
+               request = REQ_NONE;
+       }
+
        while (view_driver(display[current_view], request)) {
                int key;
                int i;
 
                foreach_view (view, i)
                        update_view(view);
+               view = display[current_view];
 
                /* Refresh, accept single keystroke of input */
                key = wgetch(status_win);
@@ -5853,7 +6431,7 @@ main(int argc, char *argv[])
                        continue;
                }
 
-               request = get_keybinding(display[current_view]->keymap, key);
+               request = get_keybinding(view->keymap, key);
 
                /* Some low-level request handling. This keeps access to
                 * status_win restricted. */
@@ -5862,13 +6440,23 @@ main(int argc, char *argv[])
                {
                        char *cmd = read_prompt(":");
 
-                       if (cmd && string_format(opt_cmd, "git %s", cmd)) {
-                               if (strncmp(cmd, "show", 4) && isspace(cmd[4])) {
-                                       opt_request = REQ_VIEW_DIFF;
+                       if (cmd) {
+                               struct view *next = VIEW(REQ_VIEW_PAGER);
+                               const char *argv[SIZEOF_ARG] = { "git" };
+                               int argc = 1;
+
+                               /* When running random commands, initially show the
+                                * command in the title. However, it maybe later be
+                                * overwritten if a commit line is selected. */
+                               string_ncopy(next->ref, cmd, strlen(cmd));
+
+                               if (!argv_from_string(argv, &argc, cmd)) {
+                                       report("Too many arguments");
+                               } else if (!prepare_update(next, argv, NULL, FORMAT_DASH)) {
+                                       report("Failed to format command");
                                } else {
-                                       opt_request = REQ_VIEW_PAGER;
+                                       open_view(view, REQ_VIEW_PAGER, OPEN_PREPARED);
                                }
-                               break;
                        }
 
                        request = REQ_NONE;
@@ -5877,8 +6465,7 @@ main(int argc, char *argv[])
                case REQ_SEARCH:
                case REQ_SEARCH_BACK:
                {
-                       const char *prompt = request == REQ_SEARCH
-                                          ? "/" : "?";
+                       const char *prompt = request == REQ_SEARCH ? "/" : "?";
                        char *search = read_prompt(prompt);
 
                        if (search)