built-in tar-tree and remote tar-tree

This makes tar-tree a built-in.  As an added bonus, you can now
say:

	git tar-tree --remote=remote-repository <ent> [<base>]

This does not work with git-daemon yet, but should work with
localhost and git over ssh transports.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Makefile b/Makefile
index 4fd6520b7edf6215c3baf78298ac309883a7935d..f4bcec496a616d111bad42b70b8289a9cde74d7c 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -161,7 +161,7 @@ PROGRAMS = \
        git-receive-pack$X git-rev-parse$X \
        git-send-pack$X git-show-branch$X git-shell$X \
        git-show-index$X git-ssh-fetch$X \
-       git-ssh-upload$X git-tar-tree$X git-unpack-file$X \
+       git-ssh-upload$X git-unpack-file$X \
        git-unpack-objects$X git-update-index$X git-update-server-info$X \
        git-upload-pack$X git-verify-pack$X git-write-tree$X \
        git-update-ref$X git-symbolic-ref$X \
@@ -171,7 +171,7 @@ PROGRAMS = \
 BUILT_INS = git-log$X git-whatchanged$X git-show$X \
        git-count-objects$X git-diff$X git-push$X \
        git-grep$X git-rev-list$X git-check-ref-format$X \
-       git-init-db$X
+       git-init-db$X git-tar-tree$X git-upload-tar$X
 
 # what 'all' will build and 'install' will install, in gitexecdir
 ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS)
@@ -220,7 +220,7 @@ LIB_OBJS = \
 BUILTIN_OBJS = \
        builtin-log.o builtin-help.o builtin-count.o builtin-diff.o builtin-push.o \
        builtin-grep.o builtin-rev-list.o builtin-check-ref-format.o \
-       builtin-init-db.o
+       builtin-init-db.o builtin-tar-tree.o builtin-upload-tar.o
 
 GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
 LIBS = $(GITLIBS) -lz

diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
new file mode 100644 (file)
index 0000000..e97e0af
--- /dev/null
+++ b/builtin-tar-tree.c
@@ -0,0 +1,408 @@
+/*
+ * Copyright (c) 2005, 2006 Rene Scharfe
+ */
+#include <time.h>
+#include "cache.h"
+#include "tree-walk.h"
+#include "commit.h"
+#include "strbuf.h"
+#include "tar.h"
+#include "builtin.h"
+#include "pkt-line.h"
+
+#define RECORDSIZE     (512)
+#define BLOCKSIZE      (RECORDSIZE * 20)
+
+static const char tar_tree_usage[] =
+"git-tar-tree [--remote=<repo>] <ent> [basedir]";
+
+static char block[BLOCKSIZE];
+static unsigned long offset;
+
+static time_t archive_time;
+
+/* tries hard to write, either succeeds or dies in the attempt */
+static void reliable_write(void *buf, unsigned long size)
+{
+       while (size > 0) {
+               long ret = xwrite(1, buf, size);
+               if (ret < 0) {
+                       if (errno == EPIPE)
+                               exit(0);
+                       die("git-tar-tree: %s", strerror(errno));
+               } else if (!ret) {
+                       die("git-tar-tree: disk full?");
+               }
+               size -= ret;
+               buf += ret;
+       }
+}
+
+/* writes out the whole block, but only if it is full */
+static void write_if_needed(void)
+{
+       if (offset == BLOCKSIZE) {
+               reliable_write(block, BLOCKSIZE);
+               offset = 0;
+       }
+}
+
+/* acquire the next record from the buffer; user must call write_if_needed() */
+static char *get_record(void)
+{
+       char *p = block + offset;
+       memset(p, 0, RECORDSIZE);
+       offset += RECORDSIZE;
+       return p;
+}
+
+/*
+ * The end of tar archives is marked by 1024 nul bytes and after that
+ * follows the rest of the block (if any).
+ */
+static void write_trailer(void)
+{
+       get_record();
+       write_if_needed();
+       get_record();
+       write_if_needed();
+       while (offset) {
+               get_record();
+               write_if_needed();
+       }
+}
+
+/*
+ * queues up writes, so that all our write(2) calls write exactly one
+ * full block; pads writes to RECORDSIZE
+ */
+static void write_blocked(void *buf, unsigned long size)
+{
+       unsigned long tail;
+
+       if (offset) {
+               unsigned long chunk = BLOCKSIZE - offset;
+               if (size < chunk)
+                       chunk = size;
+               memcpy(block + offset, buf, chunk);
+               size -= chunk;
+               offset += chunk;
+               buf += chunk;
+               write_if_needed();
+       }
+       while (size >= BLOCKSIZE) {
+               reliable_write(buf, BLOCKSIZE);
+               size -= BLOCKSIZE;
+               buf += BLOCKSIZE;
+       }
+       if (size) {
+               memcpy(block + offset, buf, size);
+               offset += size;
+       }
+       tail = offset % RECORDSIZE;
+       if (tail)  {
+               memset(block + offset, 0, RECORDSIZE - tail);
+               offset += RECORDSIZE - tail;
+       }
+       write_if_needed();
+}
+
+static void strbuf_append_string(struct strbuf *sb, const char *s)
+{
+       int slen = strlen(s);
+       int total = sb->len + slen;
+       if (total > sb->alloc) {
+               sb->buf = xrealloc(sb->buf, total);
+               sb->alloc = total;
+       }
+       memcpy(sb->buf + sb->len, s, slen);
+       sb->len = total;
+}
+
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+                                     const char *value, unsigned int valuelen)
+{
+       char *p;
+       int len, total, tmp;
+
+       /* "%u %s=%s\n" */
+       len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+       for (tmp = len; tmp > 9; tmp /= 10)
+               len++;
+
+       total = sb->len + len;
+       if (total > sb->alloc) {
+               sb->buf = xrealloc(sb->buf, total);
+               sb->alloc = total;
+       }
+
+       p = sb->buf;
+       p += sprintf(p, "%u %s=", len, keyword);
+       memcpy(p, value, valuelen);
+       p += valuelen;
+       *p = '\n';
+       sb->len = total;
+}
+
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
+{
+       char *p = (char *)header;
+       unsigned int chksum = 0;
+       while (p < header->chksum)
+               chksum += *p++;
+       chksum += sizeof(header->chksum) * ' ';
+       p += sizeof(header->chksum);
+       while (p < (char *)header + sizeof(struct ustar_header))
+               chksum += *p++;
+       return chksum;
+}
+
+static int get_path_prefix(const struct strbuf *path, int maxlen)
+{
+       int i = path->len;
+       if (i > maxlen)
+               i = maxlen;
+       while (i > 0 && path->buf[i] != '/')
+               i--;
+       return i;
+}
+
+static void write_entry(const unsigned char *sha1, struct strbuf *path,
+                        unsigned int mode, void *buffer, unsigned long size)
+{
+       struct ustar_header header;
+       struct strbuf ext_header;
+
+       memset(&header, 0, sizeof(header));
+       ext_header.buf = NULL;
+       ext_header.len = ext_header.alloc = 0;
+
+       if (!sha1) {
+               *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+               mode = 0100666;
+               strcpy(header.name, "pax_global_header");
+       } else if (!path) {
+               *header.typeflag = TYPEFLAG_EXT_HEADER;
+               mode = 0100666;
+               sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
+       } else {
+               if (S_ISDIR(mode)) {
+                       *header.typeflag = TYPEFLAG_DIR;
+                       mode |= 0777;
+               } else if (S_ISLNK(mode)) {
+                       *header.typeflag = TYPEFLAG_LNK;
+                       mode |= 0777;
+               } else if (S_ISREG(mode)) {
+                       *header.typeflag = TYPEFLAG_REG;
+                       mode |= (mode & 0100) ? 0777 : 0666;
+               } else {
+                       error("unsupported file mode: 0%o (SHA1: %s)",
+                             mode, sha1_to_hex(sha1));
+                       return;
+               }
+               if (path->len > sizeof(header.name)) {
+                       int plen = get_path_prefix(path, sizeof(header.prefix));
+                       int rest = path->len - plen - 1;
+                       if (plen > 0 && rest <= sizeof(header.name)) {
+                               memcpy(header.prefix, path->buf, plen);
+                               memcpy(header.name, path->buf + plen + 1, rest);
+                       } else {
+                               sprintf(header.name, "%s.data",
+                                       sha1_to_hex(sha1));
+                               strbuf_append_ext_header(&ext_header, "path",
+                                                        path->buf, path->len);
+                       }
+               } else
+                       memcpy(header.name, path->buf, path->len);
+       }
+
+       if (S_ISLNK(mode) && buffer) {
+               if (size > sizeof(header.linkname)) {
+                       sprintf(header.linkname, "see %s.paxheader",
+                               sha1_to_hex(sha1));
+                       strbuf_append_ext_header(&ext_header, "linkpath",
+                                                buffer, size);
+               } else
+                       memcpy(header.linkname, buffer, size);
+       }
+
+       sprintf(header.mode, "%07o", mode & 07777);
+       sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
+       sprintf(header.mtime, "%011lo", archive_time);
+
+       /* XXX: should we provide more meaningful info here? */
+       sprintf(header.uid, "%07o", 0);
+       sprintf(header.gid, "%07o", 0);
+       strncpy(header.uname, "git", 31);
+       strncpy(header.gname, "git", 31);
+       sprintf(header.devmajor, "%07o", 0);
+       sprintf(header.devminor, "%07o", 0);
+
+       memcpy(header.magic, "ustar", 6);
+       memcpy(header.version, "00", 2);
+
+       sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
+
+       if (ext_header.len > 0) {
+               write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
+               free(ext_header.buf);
+       }
+       write_blocked(&header, sizeof(header));
+       if (S_ISREG(mode) && buffer && size > 0)
+               write_blocked(buffer, size);
+}
+
+static void write_global_extended_header(const unsigned char *sha1)
+{
+       struct strbuf ext_header;
+       ext_header.buf = NULL;
+       ext_header.len = ext_header.alloc = 0;
+       strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
+       write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
+       free(ext_header.buf);
+}
+
+static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
+{
+       int pathlen = path->len;
+
+       while (tree->size) {
+               const char *name;
+               const unsigned char *sha1;
+               unsigned mode;
+               void *eltbuf;
+               char elttype[20];
+               unsigned long eltsize;
+
+               sha1 = tree_entry_extract(tree, &name, &mode);
+               update_tree_entry(tree);
+
+               eltbuf = read_sha1_file(sha1, elttype, &eltsize);
+               if (!eltbuf)
+                       die("cannot read %s", sha1_to_hex(sha1));
+
+               path->len = pathlen;
+               strbuf_append_string(path, name);
+               if (S_ISDIR(mode))
+                       strbuf_append_string(path, "/");
+
+               write_entry(sha1, path, mode, eltbuf, eltsize);
+
+               if (S_ISDIR(mode)) {
+                       struct tree_desc subtree;
+                       subtree.buf = eltbuf;
+                       subtree.size = eltsize;
+                       traverse_tree(&subtree, path);
+               }
+               free(eltbuf);
+       }
+}
+
+int generate_tar(int argc, const char **argv)
+{
+       unsigned char sha1[20], tree_sha1[20];
+       struct commit *commit;
+       struct tree_desc tree;
+       struct strbuf current_path;
+
+       current_path.buf = xmalloc(PATH_MAX);
+       current_path.alloc = PATH_MAX;
+       current_path.len = current_path.eof = 0;
+
+       setup_git_directory();
+       git_config(git_default_config);
+
+       switch (argc) {
+       case 3:
+               strbuf_append_string(&current_path, argv[2]);
+               strbuf_append_string(&current_path, "/");
+               /* FALLTHROUGH */
+       case 2:
+               if (get_sha1(argv[1], sha1))
+                       die("Not a valid object name %s", argv[1]);
+               break;
+       default:
+               usage(tar_tree_usage);
+       }
+
+       commit = lookup_commit_reference_gently(sha1, 1);
+       if (commit) {
+               write_global_extended_header(commit->object.sha1);
+               archive_time = commit->date;
+       } else
+               archive_time = time(NULL);
+
+       tree.buf = read_object_with_reference(sha1, tree_type, &tree.size,
+                                             tree_sha1);
+       if (!tree.buf)
+               die("not a reference to a tag, commit or tree object: %s",
+                   sha1_to_hex(sha1));
+
+       if (current_path.len > 0)
+               write_entry(tree_sha1, &current_path, 040777, NULL, 0);
+       traverse_tree(&tree, &current_path);
+       write_trailer();
+       free(current_path.buf);
+       return 0;
+}
+
+static const char *exec = "git-upload-tar";
+
+static int remote_tar(int argc, const char **argv)
+{
+       int fd[2], ret, len;
+       pid_t pid;
+       char buf[1024];
+       char *url;
+
+       if (argc < 3 || 4 < argc)
+               usage(tar_tree_usage);
+
+       /* --remote=<repo> */
+       url = strdup(argv[1]+9);
+       pid = git_connect(fd, url, exec);
+       if (pid < 0)
+               return 1;
+
+       packet_write(fd[1], "want %s\n", argv[2]);
+       if (argv[3])
+               packet_write(fd[1], "base %s\n", argv[3]);
+       packet_flush(fd[1]);
+
+       len = packet_read_line(fd[0], buf, sizeof(buf));
+       if (!len)
+               die("git-tar-tree: expected ACK/NAK, got EOF");
+       if (buf[len-1] == '\n')
+               buf[--len] = 0;
+       if (strcmp(buf, "ACK")) {
+               if (5 < len && !strncmp(buf, "NACK ", 5))
+                       die("git-tar-tree: NACK %s", buf + 5);
+               die("git-tar-tree: protocol error");
+       }
+       /* expect a flush */
+       len = packet_read_line(fd[0], buf, sizeof(buf));
+       if (len)
+               die("git-tar-tree: expected a flush");
+
+       /* Now, start reading from fd[0] and spit it out to stdout */
+       ret = copy_fd(fd[0], 1);
+       close(fd[0]);
+
+       ret |= finish_connect(pid);
+       return !!ret;
+}
+
+int cmd_tar_tree(int argc, const char **argv, char **envp)
+{
+       if (argc < 2)
+               usage(tar_tree_usage);
+       if (!strncmp("--remote=", argv[1], 9))
+               return remote_tar(argc, argv);
+       return generate_tar(argc, argv);
+}

diff --git a/builtin-upload-tar.c b/builtin-upload-tar.c
new file mode 100644 (file)
index 0000000..d4fa7b5
--- /dev/null
+++ b/builtin-upload-tar.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2006 Junio C Hamano
+ */
+#include "cache.h"
+#include "pkt-line.h"
+#include "exec_cmd.h"
+#include "builtin.h"
+
+static const char upload_tar_usage[] = "git-upload-tar <repo>";
+
+static int nak(const char *reason)
+{
+       packet_write(1, "NACK %s\n", reason);
+       packet_flush(1);
+       return 1;
+}
+
+int cmd_upload_tar(int argc, const char **argv, char **envp)
+{
+       int len;
+       const char *dir = argv[1];
+       char buf[8192];
+       unsigned char sha1[20];
+       char *base = NULL;
+       char hex[41];
+       int ac;
+       const char *av[4];
+
+       if (argc != 2)
+               usage(upload_tar_usage);
+       if (strlen(dir) < sizeof(buf)-1)
+               strcpy(buf, dir); /* enter-repo smudges its argument */
+       else
+               packet_write(1, "NACK insanely long repository name %s\n", dir);
+       if (!enter_repo(buf, 0)) {
+               packet_write(1, "NACK not a git archive %s\n", dir);
+               packet_flush(1);
+               return 1;
+       }
+
+       len = packet_read_line(0, buf, sizeof(buf));
+       if (len < 5 || strncmp("want ", buf, 5))
+               return nak("expected want");
+       if (buf[len-1] == '\n')
+               buf[--len] = 0;
+       if (get_sha1(buf + 5, sha1))
+               return nak("expected sha1");
+        strcpy(hex, sha1_to_hex(sha1));
+
+       len = packet_read_line(0, buf, sizeof(buf));
+       if (len) {
+               if (len < 5 || strncmp("base ", buf, 5))
+                       return nak("expected (optional) base");
+               if (buf[len-1] == '\n')
+                       buf[--len] = 0;
+               base = strdup(buf + 5);
+               len = packet_read_line(0, buf, sizeof(buf));
+       }
+       if (len)
+               return nak("expected flush");
+
+       packet_write(1, "ACK\n");
+       packet_flush(1);
+
+       ac = 0;
+       av[ac++] = "tar-tree";
+       av[ac++] = hex;
+       if (base)
+               av[ac++] = base;
+       av[ac++] = NULL;
+       execv_git_cmd(av);
+       /* should it return that is an error */
+       return 1;
+}

diff --git a/builtin.h b/builtin.h
index 60541262c462a257cd80d6edb8525b0fbbac0f71..f22783c499a94c3953d098d6edf04984cb25711a 100644 (file)
--- a/builtin.h
+++ b/builtin.h
@@ -27,5 +27,7 @@ extern int cmd_grep(int argc, const char **argv, char **envp);
 extern int cmd_rev_list(int argc, const char **argv, char **envp);
 extern int cmd_check_ref_format(int argc, const char **argv, char **envp);
 extern int cmd_init_db(int argc, const char **argv, char **envp);
+extern int cmd_tar_tree(int argc, const char **argv, char **envp);
+extern int cmd_upload_tar(int argc, const char **argv, char **envp);
 
 #endif

diff --git a/git.c b/git.c
index 3216d311b2efdd238f0eb023d6a918e0a43b54ab..fd8e9bf7f2b2f7c26984248d0afe2d2143c82cf8 100644 (file)
--- a/git.c
+++ b/git.c
@@ -50,8 +50,10 @@ static void handle_internal_command(int argc, const char **argv, char **envp)
                { "count-objects", cmd_count_objects },
                { "diff", cmd_diff },
                { "grep", cmd_grep },
-               { "rev-list", cmd_rev_list },
                { "init-db", cmd_init_db },
+               { "tar-tree", cmd_tar_tree },
+               { "upload-tar", cmd_upload_tar },
+               { "rev-list", cmd_rev_list },
                { "check-ref-format", cmd_check_ref_format }
        };
        int i;

diff --git a/tar-tree.c b/tar-tree.c
deleted file mode 100644 (file)
index 3308736..0000000
--- a/tar-tree.c
+++ /dev/null
@@ -1,350 +0,0 @@
-/*
- * Copyright (c) 2005, 2006 Rene Scharfe
- */
-#include <time.h>
-#include "cache.h"
-#include "tree-walk.h"
-#include "commit.h"
-#include "strbuf.h"
-#include "tar.h"
-
-#define RECORDSIZE     (512)
-#define BLOCKSIZE      (RECORDSIZE * 20)
-
-static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
-
-static char block[BLOCKSIZE];
-static unsigned long offset;
-
-static time_t archive_time;
-
-/* tries hard to write, either succeeds or dies in the attempt */
-static void reliable_write(void *buf, unsigned long size)
-{
-       while (size > 0) {
-               long ret = xwrite(1, buf, size);
-               if (ret < 0) {
-                       if (errno == EPIPE)
-                               exit(0);
-                       die("git-tar-tree: %s", strerror(errno));
-               } else if (!ret) {
-                       die("git-tar-tree: disk full?");
-               }
-               size -= ret;
-               buf += ret;
-       }
-}
-
-/* writes out the whole block, but only if it is full */
-static void write_if_needed(void)
-{
-       if (offset == BLOCKSIZE) {
-               reliable_write(block, BLOCKSIZE);
-               offset = 0;
-       }
-}
-
-/* acquire the next record from the buffer; user must call write_if_needed() */
-static char *get_record(void)
-{
-       char *p = block + offset;
-       memset(p, 0, RECORDSIZE);
-       offset += RECORDSIZE;
-       return p;
-}
-
-/*
- * The end of tar archives is marked by 1024 nul bytes and after that
- * follows the rest of the block (if any).
- */
-static void write_trailer(void)
-{
-       get_record();
-       write_if_needed();
-       get_record();
-       write_if_needed();
-       while (offset) {
-               get_record();
-               write_if_needed();
-       }
-}
-
-/*
- * queues up writes, so that all our write(2) calls write exactly one
- * full block; pads writes to RECORDSIZE
- */
-static void write_blocked(void *buf, unsigned long size)
-{
-       unsigned long tail;
-
-       if (offset) {
-               unsigned long chunk = BLOCKSIZE - offset;
-               if (size < chunk)
-                       chunk = size;
-               memcpy(block + offset, buf, chunk);
-               size -= chunk;
-               offset += chunk;
-               buf += chunk;
-               write_if_needed();
-       }
-       while (size >= BLOCKSIZE) {
-               reliable_write(buf, BLOCKSIZE);
-               size -= BLOCKSIZE;
-               buf += BLOCKSIZE;
-       }
-       if (size) {
-               memcpy(block + offset, buf, size);
-               offset += size;
-       }
-       tail = offset % RECORDSIZE;
-       if (tail)  {
-               memset(block + offset, 0, RECORDSIZE - tail);
-               offset += RECORDSIZE - tail;
-       }
-       write_if_needed();
-}
-
-static void strbuf_append_string(struct strbuf *sb, const char *s)
-{
-       int slen = strlen(s);
-       int total = sb->len + slen;
-       if (total > sb->alloc) {
-               sb->buf = xrealloc(sb->buf, total);
-               sb->alloc = total;
-       }
-       memcpy(sb->buf + sb->len, s, slen);
-       sb->len = total;
-}
-
-/*
- * pax extended header records have the format "%u %s=%s\n".  %u contains
- * the size of the whole string (including the %u), the first %s is the
- * keyword, the second one is the value.  This function constructs such a
- * string and appends it to a struct strbuf.
- */
-static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
-                                     const char *value, unsigned int valuelen)
-{
-       char *p;
-       int len, total, tmp;
-
-       /* "%u %s=%s\n" */
-       len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
-       for (tmp = len; tmp > 9; tmp /= 10)
-               len++;
-
-       total = sb->len + len;
-       if (total > sb->alloc) {
-               sb->buf = xrealloc(sb->buf, total);
-               sb->alloc = total;
-       }
-
-       p = sb->buf;
-       p += sprintf(p, "%u %s=", len, keyword);
-       memcpy(p, value, valuelen);
-       p += valuelen;
-       *p = '\n';
-       sb->len = total;
-}
-
-static unsigned int ustar_header_chksum(const struct ustar_header *header)
-{
-       char *p = (char *)header;
-       unsigned int chksum = 0;
-       while (p < header->chksum)
-               chksum += *p++;
-       chksum += sizeof(header->chksum) * ' ';
-       p += sizeof(header->chksum);
-       while (p < (char *)header + sizeof(struct ustar_header))
-               chksum += *p++;
-       return chksum;
-}
-
-static int get_path_prefix(const struct strbuf *path, int maxlen)
-{
-       int i = path->len;
-       if (i > maxlen)
-               i = maxlen;
-       while (i > 0 && path->buf[i] != '/')
-               i--;
-       return i;
-}
-
-static void write_entry(const unsigned char *sha1, struct strbuf *path,
-                        unsigned int mode, void *buffer, unsigned long size)
-{
-       struct ustar_header header;
-       struct strbuf ext_header;
-
-       memset(&header, 0, sizeof(header));
-       ext_header.buf = NULL;
-       ext_header.len = ext_header.alloc = 0;
-
-       if (!sha1) {
-               *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
-               mode = 0100666;
-               strcpy(header.name, "pax_global_header");
-       } else if (!path) {
-               *header.typeflag = TYPEFLAG_EXT_HEADER;
-               mode = 0100666;
-               sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
-       } else {
-               if (S_ISDIR(mode)) {
-                       *header.typeflag = TYPEFLAG_DIR;
-                       mode |= 0777;
-               } else if (S_ISLNK(mode)) {
-                       *header.typeflag = TYPEFLAG_LNK;
-                       mode |= 0777;
-               } else if (S_ISREG(mode)) {
-                       *header.typeflag = TYPEFLAG_REG;
-                       mode |= (mode & 0100) ? 0777 : 0666;
-               } else {
-                       error("unsupported file mode: 0%o (SHA1: %s)",
-                             mode, sha1_to_hex(sha1));
-                       return;
-               }
-               if (path->len > sizeof(header.name)) {
-                       int plen = get_path_prefix(path, sizeof(header.prefix));
-                       int rest = path->len - plen - 1;
-                       if (plen > 0 && rest <= sizeof(header.name)) {
-                               memcpy(header.prefix, path->buf, plen);
-                               memcpy(header.name, path->buf + plen + 1, rest);
-                       } else {
-                               sprintf(header.name, "%s.data",
-                                       sha1_to_hex(sha1));
-                               strbuf_append_ext_header(&ext_header, "path",
-                                                        path->buf, path->len);
-                       }
-               } else
-                       memcpy(header.name, path->buf, path->len);
-       }
-
-       if (S_ISLNK(mode) && buffer) {
-               if (size > sizeof(header.linkname)) {
-                       sprintf(header.linkname, "see %s.paxheader",
-                               sha1_to_hex(sha1));
-                       strbuf_append_ext_header(&ext_header, "linkpath",
-                                                buffer, size);
-               } else
-                       memcpy(header.linkname, buffer, size);
-       }
-
-       sprintf(header.mode, "%07o", mode & 07777);
-       sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
-       sprintf(header.mtime, "%011lo", archive_time);
-
-       /* XXX: should we provide more meaningful info here? */
-       sprintf(header.uid, "%07o", 0);
-       sprintf(header.gid, "%07o", 0);
-       strncpy(header.uname, "git", 31);
-       strncpy(header.gname, "git", 31);
-       sprintf(header.devmajor, "%07o", 0);
-       sprintf(header.devminor, "%07o", 0);
-
-       memcpy(header.magic, "ustar", 6);
-       memcpy(header.version, "00", 2);
-
-       sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
-
-       if (ext_header.len > 0) {
-               write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
-               free(ext_header.buf);
-       }
-       write_blocked(&header, sizeof(header));
-       if (S_ISREG(mode) && buffer && size > 0)
-               write_blocked(buffer, size);
-}
-
-static void write_global_extended_header(const unsigned char *sha1)
-{
-       struct strbuf ext_header;
-       ext_header.buf = NULL;
-       ext_header.len = ext_header.alloc = 0;
-       strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
-       write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
-       free(ext_header.buf);
-}
-
-static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
-{
-       int pathlen = path->len;
-
-       while (tree->size) {
-               const char *name;
-               const unsigned char *sha1;
-               unsigned mode;
-               void *eltbuf;
-               char elttype[20];
-               unsigned long eltsize;
-
-               sha1 = tree_entry_extract(tree, &name, &mode);
-               update_tree_entry(tree);
-
-               eltbuf = read_sha1_file(sha1, elttype, &eltsize);
-               if (!eltbuf)
-                       die("cannot read %s", sha1_to_hex(sha1));
-
-               path->len = pathlen;
-               strbuf_append_string(path, name);
-               if (S_ISDIR(mode))
-                       strbuf_append_string(path, "/");
-
-               write_entry(sha1, path, mode, eltbuf, eltsize);
-
-               if (S_ISDIR(mode)) {
-                       struct tree_desc subtree;
-                       subtree.buf = eltbuf;
-                       subtree.size = eltsize;
-                       traverse_tree(&subtree, path);
-               }
-               free(eltbuf);
-       }
-}
-
-int main(int argc, char **argv)
-{
-       unsigned char sha1[20], tree_sha1[20];
-       struct commit *commit;
-       struct tree_desc tree;
-       struct strbuf current_path;
-
-       current_path.buf = xmalloc(PATH_MAX);
-       current_path.alloc = PATH_MAX;
-       current_path.len = current_path.eof = 0;
-
-       setup_git_directory();
-       git_config(git_default_config);
-
-       switch (argc) {
-       case 3:
-               strbuf_append_string(&current_path, argv[2]);
-               strbuf_append_string(&current_path, "/");
-               /* FALLTHROUGH */
-       case 2:
-               if (get_sha1(argv[1], sha1))
-                       die("Not a valid object name %s", argv[1]);
-               break;
-       default:
-               usage(tar_tree_usage);
-       }
-
-       commit = lookup_commit_reference_gently(sha1, 1);
-       if (commit) {
-               write_global_extended_header(commit->object.sha1);
-               archive_time = commit->date;
-       } else
-               archive_time = time(NULL);
-
-       tree.buf = read_object_with_reference(sha1, tree_type, &tree.size,
-                                             tree_sha1);
-       if (!tree.buf)
-               die("not a reference to a tag, commit or tree object: %s",
-                   sha1_to_hex(sha1));
-
-       if (current_path.len > 0)
-               write_entry(tree_sha1, &current_path, 040777, NULL, 0);
-       traverse_tree(&tree, &current_path);
-       write_trailer();
-       free(current_path.buf);
-       return 0;
-}