Fix up "git log --follow" a bit..

This fixes "git log --follow" to hopefully not leak memory any more, and
also cleans it up a bit to look more like some of the other functions that
use "diff_queued_diff" (by *not* using it directly as a global in the
code, but by instead just taking a pointer to the diff queue and using
that).

As to "diff_queued_diff", I think it would be better off not as a global
at all, but as being just an entry in the "struct diff_options" structure,
but that's a separate issue, and there may be some subtle reason for why
it's currently a global.

Anyway, no real changes. Instead of having a magical first entry in the
diff-queue, we now end up just keeping the diff-queue clean, and keeping
our "preferred" file pairing in an internal "choice" variable. That makes
it easy to switch the choice around when we find a better one.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/tree-diff.c b/tree-diff.c
index 42924e9b63919a74fa08b17d24700325c7700f11..26bdbdd2bfea5eab99b9f1c38936efe56f1ab45a 100644 (file)
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -305,9 +305,15 @@ static inline int diff_might_be_rename(void)
 static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 {
        struct diff_options diff_opts;
-       const char *paths[2];
+       struct diff_queue_struct *q = &diff_queued_diff;
+       struct diff_filepair *choice;
+       const char *paths[1];
        int i;
 
+       /* Remove the file creation entry from the diff queue, and remember it */
+       choice = q->queue[0];
+       q->nr = 0;
+
        diff_setup(&diff_opts);
        diff_opts.recursive = 1;
        diff_opts.detect_rename = DIFF_DETECT_RENAME;
@@ -320,17 +326,21 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
        diff_tree(t1, t2, base, &diff_opts);
        diffcore_std(&diff_opts);
 
-       /* NOTE! Ignore the first diff! That was the old one! */
-       for (i = 1; i < diff_queued_diff.nr; i++) {
-               struct diff_filepair *p = diff_queued_diff.queue[i];
+       /* Go through the new set of filepairing, and see if we find a more interesting one */
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
 
                /*
                 * Found a source? Not only do we use that for the new
-                * diff_queued_diff, we also use that as the path in
+                * diff_queued_diff, we will also use that as the path in
                 * the future!
                 */
                if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
-                       diff_queued_diff.queue[0] = p;
+                       /* Switch the file-pairs around */
+                       q->queue[i] = choice;
+                       choice = p;
+
+                       /* Update the path we use from now on.. */
                        opt->paths[0] = xstrdup(p->one->path);
                        diff_tree_setup_paths(opt->paths, opt);
                        break;
@@ -338,10 +348,19 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
        }
 
        /*
-        * Then, ignore any but the first entry! It might be the old one,
-        * or it might be the rename/copy we found
+        * Then, discard all the non-relevane file pairs...
+        */
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               diff_free_filepair(p);
+       }
+
+       /*
+        * .. and re-instate the one we want (which might be either the
+        * original one, or the rename/copy we found)
         */
-       diff_queued_diff.nr = 1;
+       q->queue[0] = choice;
+       q->nr = 1;
 }
 
 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)