Refactor fast-import branch creation from existing commit

To resolve a corner case uncovered by Simon Hausmann I need to
reuse the logic for the SHA-1 expression version of the 'from '
command within the mark version of the 'from ' command.  This change
doesn't alter any functionality, but is merely breaking the common
code out to a function that I can reuse.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/fast-import.c b/fast-import.c
index f308db76300986ce46abe7df60c6f9c73b50234a..f5107df74d248afc7e2e2d45f7128fb7779fdfdc 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -1657,6 +1657,33 @@ static void file_change_deleteall(struct branch *b)
        load_tree(&b->branch_tree);
 }
 
+static void cmd_from_commit(struct branch *b, char *buf, unsigned long size)
+{
+       if (!buf || size < 46)
+               die("Not a valid commit: %s", sha1_to_hex(b->sha1));
+       if (memcmp("tree ", buf, 5)
+               || get_sha1_hex(buf + 5, b->branch_tree.versions[1].sha1))
+               die("The commit %s is corrupt", sha1_to_hex(b->sha1));
+       hashcpy(b->branch_tree.versions[0].sha1,
+               b->branch_tree.versions[1].sha1);
+}
+
+static void cmd_from_existing(struct branch *b)
+{
+       if (is_null_sha1(b->sha1)) {
+               hashclr(b->branch_tree.versions[0].sha1);
+               hashclr(b->branch_tree.versions[1].sha1);
+       } else {
+               unsigned long size;
+               char *buf;
+
+               buf = read_object_with_reference(b->sha1,
+                       commit_type, &size, b->sha1);
+               cmd_from_commit(b, buf, size);
+               free(buf);
+       }
+}
+
 static void cmd_from(struct branch *b)
 {
        const char *from;
@@ -1688,34 +1715,11 @@ static void cmd_from(struct branch *b)
                        die("Mark :%" PRIuMAX " not a commit", idnum);
                hashcpy(b->sha1, oe->sha1);
                buf = gfi_unpack_entry(oe, &size);
-               if (!buf || size < 46)
-                       die("Not a valid commit: %s", from);
-               if (memcmp("tree ", buf, 5)
-                       || get_sha1_hex(buf + 5, b->branch_tree.versions[1].sha1))
-                       die("The commit %s is corrupt", sha1_to_hex(b->sha1));
+               cmd_from_commit(b, buf, size);
                free(buf);
-               hashcpy(b->branch_tree.versions[0].sha1,
-                       b->branch_tree.versions[1].sha1);
-       } else if (!get_sha1(from, b->sha1)) {
-               if (is_null_sha1(b->sha1)) {
-                       hashclr(b->branch_tree.versions[0].sha1);
-                       hashclr(b->branch_tree.versions[1].sha1);
-               } else {
-                       unsigned long size;
-                       char *buf;
-
-                       buf = read_object_with_reference(b->sha1,
-                               commit_type, &size, b->sha1);
-                       if (!buf || size < 46)
-                               die("Not a valid commit: %s", from);
-                       if (memcmp("tree ", buf, 5)
-                               || get_sha1_hex(buf + 5, b->branch_tree.versions[1].sha1))
-                               die("The commit %s is corrupt", sha1_to_hex(b->sha1));
-                       free(buf);
-                       hashcpy(b->branch_tree.versions[0].sha1,
-                               b->branch_tree.versions[1].sha1);
-               }
-       } else
+       } else if (!get_sha1(from, b->sha1))
+               cmd_from_existing(b);
+       else
                die("Invalid ref name or SHA1 expression: %s", from);
 
        read_next_command();