Convert update-ref to use ref_lock API.

This conversion also adds the '-m' switch to update-ref allowing
the caller to record why the ref is changing.  At present this is
merely copied down into the ref_lock API.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 475237f..f0e710a 100644 (file)
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -7,7 +7,7 @@ git-update-ref - update the object name stored in a ref safely
 
 SYNOPSIS
 --------
-'git-update-ref' <ref> <newvalue> [<oldvalue>]
+'git-update-ref' <ref> <newvalue> [<oldvalue>] [-m <reason>]
 
 DESCRIPTION
 -----------

diff --git a/update-ref.c b/update-ref.c
index fd48742..a1e6bb9 100644 (file)
--- a/update-ref.c
+++ b/update-ref.c
@@ -1,85 +1,56 @@
 #include "cache.h"
 #include "refs.h"
 
-static const char git_update_ref_usage[] = "git-update-ref <refname> <value> [<oldval>]";
-
-static int re_verify(const char *path, unsigned char *oldsha1, unsigned char *currsha1)
-{
-       char buf[40];
-       int fd = open(path, O_RDONLY), nr;
-       if (fd < 0)
-               return -1;
-       nr = read(fd, buf, 40);
-       close(fd);
-       if (nr != 40 || get_sha1_hex(buf, currsha1) < 0)
-               return -1;
-       return memcmp(oldsha1, currsha1, 20) ? -1 : 0;
-}
+static const char git_update_ref_usage[] =
+"git-update-ref <refname> <value> [<oldval>] [-m <reason>]";
 
 int main(int argc, char **argv)
 {
-       char *hex;
-       const char *refname, *value, *oldval, *path;
-       char *lockpath;
-       unsigned char sha1[20], oldsha1[20], currsha1[20];
-       int fd, written;
+       const char *refname=NULL, *value=NULL, *oldval=NULL, *msg=NULL;
+       struct ref_lock *lock;
+       unsigned char sha1[20], oldsha1[20];
+       int i;
 
        setup_git_directory();
        git_config(git_default_config);
-       if (argc < 3 || argc > 4)
+
+       for (i = 1; i < argc; i++) {
+               if (!strcmp("-m", argv[i])) {
+                       if (i+1 >= argc)
+                               usage(git_update_ref_usage);
+                       msg = argv[++i];
+                       if (!*msg)
+                               die("Refusing to perform update with empty message.");
+                       if (strchr(msg, '\n'))
+                               die("Refusing to perform update with \\n in message.");
+                       continue;
+               }
+               if (!refname) {
+                       refname = argv[i];
+                       continue;
+               }
+               if (!value) {
+                       value = argv[i];
+                       continue;
+               }
+               if (!oldval) {
+                       oldval = argv[i];
+                       continue;
+               }
+       }
+       if (!refname || !value)
                usage(git_update_ref_usage);
 
-       refname = argv[1];
-       value = argv[2];
-       oldval = argv[3];
        if (get_sha1(value, sha1))
                die("%s: not a valid SHA1", value);
        memset(oldsha1, 0, 20);
        if (oldval && get_sha1(oldval, oldsha1))
                die("%s: not a valid old SHA1", oldval);
 
-       path = resolve_ref(git_path("%s", refname), currsha1, !!oldval);
-       if (!path)
-               die("No such ref: %s", refname);
-
-       if (oldval) {
-               if (memcmp(currsha1, oldsha1, 20))
-                       die("Ref %s is at %s but expected %s", refname, sha1_to_hex(currsha1), sha1_to_hex(oldsha1));
-               /* Nothing to do? */
-               if (!memcmp(oldsha1, sha1, 20))
-                       exit(0);
-       }
-       path = strdup(path);
-       lockpath = mkpath("%s.lock", path);
-       if (safe_create_leading_directories(lockpath) < 0)
-               die("Unable to create all of %s", lockpath);
-
-       fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
-       if (fd < 0)
-               die("Unable to create %s", lockpath);
-       hex = sha1_to_hex(sha1);
-       hex[40] = '\n';
-       written = write(fd, hex, 41);
-       close(fd);
-       if (written != 41) {
-               unlink(lockpath);
-               die("Unable to write to %s", lockpath);
-       }
-
-       /*
-        * Re-read the ref after getting the lock to verify
-        */
-       if (oldval && re_verify(path, oldsha1, currsha1) < 0) {
-               unlink(lockpath);
-               die("Ref lock failed");
-       }
-
-       /*
-        * Finally, replace the old ref with the new one
-        */
-       if (rename(lockpath, path) < 0) {
-               unlink(lockpath);
-               die("Unable to create %s", path);
-       }
+       lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
+       if (!lock)
+               return 1;
+       if (write_ref_sha1(lock, sha1, msg) < 0)
+               return 1;
        return 0;
 }