commit_lock_file_to(): refactor a helper out of commit_lock_file()

[thirdparty/git.git] / lockfile.c

diff --git a/lockfile.c b/lockfile.c
index 5f5bcfffbe25b6145f1683a989399f44880b3d5d..cf7f4d0470e39a339bc1a34317756e8ec6df76a3 100644 (file)
--- a/lockfile.c
+++ b/lockfile.c
@@ -43,9 +43,9 @@
  *   Same as the previous state, except that the lockfile is closed
  *   and fd is -1.
  *
- * - Unlocked (after commit_lock_file(), rollback_lock_file(), a
- *   failed attempt to lock, or a failed close_lock_file()).  In this
- *   state:
+ * - Unlocked (after commit_lock_file(), commit_lock_file_to(),
+ *   rollback_lock_file(), a failed attempt to lock, or a failed
+ *   close_lock_file()).  In this state:
  *   - active is unset
  *   - filename is empty (usually, though there are transitory
  *     states in which this condition doesn't hold). Client code should
@@ -76,32 +76,28 @@ static void remove_lock_file_on_signal(int signo)
 }
 
 /*
- * p = absolute or relative path name
+ * path = absolute or relative path name
  *
- * Return a pointer into p showing the beginning of the last path name
- * element.  If p is empty or the root directory ("/"), just return p.
+ * Remove the last path name element from path (leaving the preceding
+ * "/", if any).  If path is empty or the root directory ("/"), set
+ * path to the empty string.
  */
-static char *last_path_elm(char *p)
+static void trim_last_path_component(struct strbuf *path)
 {
-       /* r starts pointing to null at the end of the string */
-       char *r = strchr(p, '\0');
-
-       if (r == p)
-               return p; /* just return empty string */
-
-       r--; /* back up to last non-null character */
+       int i = path->len;
 
        /* back up past trailing slashes, if any */
-       while (r > p && *r == '/')
-               r--;
+       while (i && path->buf[i - 1] == '/')
+               i--;
 
        /*
-        * then go backwards until I hit a slash, or the beginning of
-        * the string
+        * then go backwards until a slash, or the beginning of the
+        * string
         */
-       while (r > p && *(r-1) != '/')
-               r--;
-       return r;
+       while (i && path->buf[i - 1] != '/')
+               i--;
+
+       strbuf_setlen(path, i);
 }
 
 
@@ -131,14 +127,12 @@ static void resolve_symlink(struct strbuf *path)
                if (is_absolute_path(link.buf))
                        /* absolute path simply replaces p */
                        strbuf_reset(path);
-               else {
+               else
                        /*
                         * link is a relative path, so replace the
                         * last element of p with it.
                         */
-                       char *r = last_path_elm(path->buf);
-                       strbuf_setlen(path, r - path->buf);
-               }
+                       trim_last_path_component(path);
 
                strbuf_addbuf(path, &link);
        }
@@ -290,23 +284,15 @@ int reopen_lock_file(struct lock_file *lk)
        return lk->fd;
 }
 
-int commit_lock_file(struct lock_file *lk)
+int commit_lock_file_to(struct lock_file *lk, const char *path)
 {
-       static struct strbuf result_file = STRBUF_INIT;
-       int err;
-
        if (!lk->active)
-               die("BUG: attempt to commit unlocked object");
+               die("BUG: attempt to commit unlocked object to \"%s\"", path);
 
        if (close_lock_file(lk))
                return -1;
 
-       /* remove ".lock": */
-       strbuf_add(&result_file, lk->filename.buf,
-                  lk->filename.len - LOCK_SUFFIX_LEN);
-       err = rename(lk->filename.buf, result_file.buf);
-       strbuf_reset(&result_file);
-       if (err) {
+       if (rename(lk->filename.buf, path)) {
                int save_errno = errno;
                rollback_lock_file(lk);
                errno = save_errno;
@@ -318,6 +304,26 @@ int commit_lock_file(struct lock_file *lk)
        return 0;
 }
 
+int commit_lock_file(struct lock_file *lk)
+{
+       static struct strbuf result_file = STRBUF_INIT;
+       int err;
+
+       if (!lk->active)
+               die("BUG: attempt to commit unlocked object");
+
+       if (lk->filename.len <= LOCK_SUFFIX_LEN ||
+           strcmp(lk->filename.buf + lk->filename.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
+               die("BUG: lockfile filename corrupt");
+
+       /* remove ".lock": */
+       strbuf_add(&result_file, lk->filename.buf,
+                  lk->filename.len - LOCK_SUFFIX_LEN);
+       err = commit_lock_file_to(lk, result_file.buf);
+       strbuf_reset(&result_file);
+       return err;
+}
+
 int hold_locked_index(struct lock_file *lk, int die_on_error)
 {
        return hold_lock_file_for_update(lk, get_index_file(),