From: Andreas Ericsson Date: Tue, 15 Nov 2005 23:31:25 +0000 (+0100) Subject: C implementation of the 'git' program, take two. X-Git-Tag: v0.99.9k~3^2~21 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=8e49d50388211a0f3e7286f6ee600bf7736f4814;p=git.git C implementation of the 'git' program, take two. This patch provides a C implementation of the 'git' program and introduces support for putting the git-* commands in a directory of their own. It also saves some time on executing those commands in a tight loop and it prints the currently available git commands in a nicely formatted list. The location of the GIT_EXEC_PATH (name discussion's closed, thank gods) can be obtained by running git --exec-path which will hopefully give porcelainistas ample time to adapt their heavy-duty loops to call the core programs directly and thus save the extra fork() / execve() overhead, although that's not really necessary any more. The --exec-path value is prepended to $PATH, so the git-* programs should Just Work without ever requiring any changes to how they call other programs in the suite. Some timing values for 10000 invocations of git-var >&/dev/null: git.sh: 24.194s git.c: 9.044s git-var: 7.377s The git- behaviour can, along with the someday-to-be-deprecated git- form of invocation, be indefinitely retained by adding the following line to one's .bash_profile or equivalent: PATH=$PATH:$(git --exec-path) Experimental libraries can be used by either setting the environment variable GIT_EXEC_PATH, or by using git --exec-path=/some/experimental/exec-path Relative paths are properly grok'ed as exec-path values. Signed-off-by: Andreas Ericsson Signed-off-by: Junio C Hamano --- diff --git a/Makefile b/Makefile index 21bc3d384..ebff990b5 100644 --- a/Makefile +++ b/Makefile @@ -88,7 +88,7 @@ SCRIPT_SH = \ git-prune.sh git-pull.sh git-push.sh git-rebase.sh \ git-repack.sh git-request-pull.sh git-reset.sh \ git-resolve.sh git-revert.sh git-sh-setup.sh git-status.sh \ - git-tag.sh git-verify-tag.sh git-whatchanged.sh git.sh \ + git-tag.sh git-verify-tag.sh git-whatchanged.sh \ git-applymbox.sh git-applypatch.sh git-am.sh \ git-merge.sh git-merge-stupid.sh git-merge-octopus.sh \ git-merge-resolve.sh git-merge-ours.sh git-grep.sh \ @@ -334,19 +334,15 @@ SCRIPTS = $(patsubst %.sh,%,$(SCRIPT_SH)) \ export prefix TAR INSTALL DESTDIR SHELL_PATH template_dir ### Build rules -all: $(PROGRAMS) $(SCRIPTS) +all: $(PROGRAMS) $(SCRIPTS) git all: $(MAKE) -C templates -git: git.sh Makefile - rm -f $@+ $@ - sed -e '1s|#!.*/sh|#!$(call shq,$(SHELL_PATH))|' \ - -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \ - -e 's/@@X@@/$(X)/g' \ - $(GIT_LIST_TWEAK) <$@.sh >$@+ - chmod +x $@+ - mv $@+ $@ +# Only use $(CFLAGS). We don't need anything else. +git: git.c Makefile + $(CC) -DGIT_EXEC_PATH='"$(bindir)"' -DGIT_VERSION='"$(GIT_VERSION)"' \ + $(CFLAGS) $@.c -o $@ $(filter-out git,$(patsubst %.sh,%,$(SCRIPT_SH))) : % : %.sh rm -f $@ @@ -431,9 +427,9 @@ check: ### Installation rules -install: $(PROGRAMS) $(SCRIPTS) +install: $(PROGRAMS) $(SCRIPTS) git $(INSTALL) -d -m755 $(call shellquote,$(DESTDIR)$(bindir)) - $(INSTALL) $(PROGRAMS) $(SCRIPTS) $(call shellquote,$(DESTDIR)$(bindir)) + $(INSTALL) git $(PROGRAMS) $(SCRIPTS) $(call shellquote,$(DESTDIR)$(bindir)) $(MAKE) -C templates install $(INSTALL) -d -m755 $(call shellquote,$(DESTDIR)$(GIT_PYTHON_DIR)) $(INSTALL) $(PYMODULES) $(call shellquote,$(DESTDIR)$(GIT_PYTHON_DIR)) diff --git a/git.c b/git.c new file mode 100644 index 000000000..d18980135 --- /dev/null +++ b/git.c @@ -0,0 +1,229 @@ +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef PATH_MAX +# define PATH_MAX 4096 +#endif + +static const char git_usage[] = + "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]"; + +struct string_list { + size_t len; + char *str; + struct string_list *next; +}; + +/* most gui terms set COLUMNS (although some don't export it) */ +static int term_columns(void) +{ + char *col_string = getenv("COLUMNS"); + int n_cols = 0; + + if (col_string && (n_cols = atoi(col_string)) > 0) + return n_cols; + + return 80; +} + +static inline void mput_char(char c, unsigned int num) +{ + while(num--) + putchar(c); +} + +static void pretty_print_string_list(struct string_list *list, int longest) +{ + int cols = 1; + int space = longest + 1; /* min 1 SP between words */ + int max_cols = term_columns() - 1; /* don't print *on* the edge */ + + if (space < max_cols) + cols = max_cols / space; + + while (list) { + int c; + printf(" "); + + for (c = cols; c && list; list = list->next) { + printf("%s", list->str); + + if (--c) + mput_char(' ', space - list->len); + } + putchar('\n'); + } +} + +static void list_commands(const char *exec_path, const char *pattern) +{ + struct string_list *list = NULL, *tail = NULL; + unsigned int longest = 0, i; + glob_t gl; + + if (chdir(exec_path) < 0) { + printf("git: '%s': %s\n", exec_path, strerror(errno)); + exit(1); + } + + i = glob(pattern, 0, NULL, &gl); + switch(i) { + case GLOB_NOSPACE: + puts("Out of memory when running glob()"); + exit(2); + case GLOB_ABORTED: + printf("'%s': Read error: %s\n", exec_path, strerror(errno)); + exit(2); + case GLOB_NOMATCH: + printf("No git commands available in '%s'.\n", exec_path); + printf("Do you need to specify --exec-path or set GIT_EXEC_PATH?\n"); + exit(1); + } + + for (i = 0; i < gl.gl_pathc; i++) { + int len = strlen(gl.gl_pathv[i] + 4); + + if (access(gl.gl_pathv[i], X_OK)) + continue; + + if (longest < len) + longest = len; + + if (!tail) + tail = list = malloc(sizeof(struct string_list)); + else { + tail->next = malloc(sizeof(struct string_list)); + tail = tail->next; + } + tail->len = len; + tail->str = gl.gl_pathv[i] + 4; + tail->next = NULL; + } + + printf("git commands available in '%s'\n", exec_path); + printf("----------------------------"); + mput_char('-', strlen(exec_path)); + putchar('\n'); + pretty_print_string_list(list, longest); + putchar('\n'); +} + +#ifdef __GNUC__ +static void usage(const char *exec_path, const char *fmt, ...) + __attribute__((__format__(__printf__, 2, 3), __noreturn__)); +#endif +static void usage(const char *exec_path, const char *fmt, ...) +{ + if (fmt) { + va_list ap; + + va_start(ap, fmt); + printf("git: "); + vprintf(fmt, ap); + va_end(ap); + putchar('\n'); + } + else + puts(git_usage); + + putchar('\n'); + + if(exec_path) + list_commands(exec_path, "git-*"); + + exit(1); +} + +static void prepend_to_path(const char *dir, int len) +{ + char *path, *old_path = getenv("PATH"); + int path_len = len; + + if (!old_path) + old_path = "/bin:/usr/bin:."; + + path_len = len + strlen(old_path) + 1; + + path = malloc(path_len + 1); + path[path_len + 1] = '\0'; + + memcpy(path, dir, len); + path[len] = ':'; + memcpy(path + len + 1, old_path, path_len - len); + + setenv("PATH", path, 1); +} + +int main(int argc, char **argv, char **envp) +{ + char git_command[PATH_MAX + 1]; + char wd[PATH_MAX + 1]; + int i, len, show_help = 0; + char *exec_path = getenv("GIT_EXEC_PATH"); + + getcwd(wd, PATH_MAX); + + if (!exec_path) + exec_path = GIT_EXEC_PATH; + + for (i = 1; i < argc; i++) { + char *arg = argv[i]; + + if (strncmp(arg, "--", 2)) + break; + + arg += 2; + + if (!strncmp(arg, "exec-path", 9)) { + arg += 9; + if (*arg == '=') + exec_path = arg + 1; + else { + puts(exec_path); + exit(0); + } + } + else if (!strcmp(arg, "version")) { + printf("git version %s\n", GIT_VERSION); + exit(0); + } + else if (!strcmp(arg, "help")) + show_help = 1; + else if (!show_help) + usage(NULL, NULL); + } + + if (i >= argc || show_help) + usage(exec_path, NULL); + + /* allow relative paths, but run with exact */ + if (chdir(exec_path)) { + printf("git: '%s': %s\n", exec_path, strerror(errno)); + exit (1); + } + + getcwd(git_command, sizeof(git_command)); + chdir(wd); + + len = strlen(git_command); + prepend_to_path(git_command, len); + + strncat(&git_command[len], "/git-", sizeof(git_command) - len); + len += 5; + strncat(&git_command[len], argv[i], sizeof(git_command) - len); + + if (access(git_command, X_OK)) + usage(exec_path, "'%s' is not a git-command", argv[i]); + + /* execve() can only ever return if it fails */ + execve(git_command, &argv[i], envp); + printf("Failed to run command '%s': %s\n", git_command, strerror(errno)); + + return 1; +} diff --git a/git.sh b/git.sh deleted file mode 100755 index 94940aea2..000000000 --- a/git.sh +++ /dev/null @@ -1,76 +0,0 @@ -#!/bin/sh - -cmd= -path=$(dirname "$0") -case "$#" in -0) ;; -*) cmd="$1" - shift - case "$cmd" in - -v|--v|--ve|--ver|--vers|--versi|--versio|--version) - echo "git version @@GIT_VERSION@@" - exit 0 ;; - esac - - test -x "$path/git-$cmd" && exec "$path/git-$cmd" "$@" - - case '@@X@@' in - '') - ;; - *) - test -x "$path/git-$cmd@@X@@" && - exec "$path/git-$cmd@@X@@" "$@" - ;; - esac - ;; -esac - -echo "Usage: git COMMAND [OPTIONS] [TARGET]" -if [ -n "$cmd" ]; then - echo "git command '$cmd' not found." -fi -echo "git commands are:" - -fmt <<\EOF | sed -e 's/^/ /' -add -apply -archimport -bisect -branch -checkout -cherry -clone -commit -count-objects -cvsimport -diff -fetch -format-patch -fsck-objects -get-tar-commit-id -init-db -log -ls-remote -octopus -pack-objects -parse-remote -patch-id -prune -pull -push -rebase -relink -rename -repack -request-pull -reset -resolve -revert -send-email -shortlog -show-branch -status -tag -verify-tag -whatchanged -EOF