[PATCH] Rename/copy detection fix.
[git.git] / diff.c
diff --git a/diff.c b/diff.c
index 4b2d105..ababcaa 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -283,12 +283,6 @@ int diff_populate_filespec(struct diff_filespec *s)
        return 0;
 }
 
-void diff_free_filepair(struct diff_filepair *p)
-{
-       free(p->xfrm_msg);
-       free(p);
-}
-
 void diff_free_filespec_data(struct diff_filespec *s)
 {
        if (s->should_free)
@@ -501,9 +495,9 @@ struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
        struct diff_filepair *dp = xmalloc(sizeof(*dp));
        dp->one = one;
        dp->two = two;
-       dp->xfrm_msg = NULL;
+       dp->score = 0;
        dp->orig_order = queue->nr;
-       dp->xfrm_work = 0;
+       dp->rename_rank = 0;
        diff_q(queue, dp);
        return dp;
 }
@@ -522,23 +516,7 @@ static void diff_flush_raw(struct diff_filepair *p)
               p->two->path, line_termination);
 }
 
-static void diff_flush_patch(struct diff_filepair *p)
-{
-       const char *name, *other;
-
-       name = p->one->path;
-       other = (strcmp(name, p->two->path) ? p->two->path : NULL);
-       if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
-           (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
-               return; /* no tree diffs in patch format */ 
-
-       if (DIFF_PAIR_UNMERGED(p))
-               run_external_diff(name, NULL, NULL, NULL, NULL);
-       else
-               run_external_diff(name, other, p->one, p->two, p->xfrm_msg);
-}
-
-static int uninteresting(struct diff_filepair *p)
+int diff_unmodified_pair(struct diff_filepair *p)
 {
        /* This function is written stricter than necessary to support
         * the currently implemented transformers, but the idea is to
@@ -570,12 +548,70 @@ static int uninteresting(struct diff_filepair *p)
        return 0;
 }
 
+static void diff_flush_patch(struct diff_filepair *p, const char *msg)
+{
+       const char *name, *other;
+
+       /* diffcore_prune() keeps "stay" entries for diff-raw
+        * copy/rename detection, but when we are generating
+        * patches we do not need them.
+        */
+       if (diff_unmodified_pair(p))
+               return;
+
+       name = p->one->path;
+       other = (strcmp(name, p->two->path) ? p->two->path : NULL);
+       if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
+           (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
+               return; /* no tree diffs in patch format */ 
+
+       if (DIFF_PAIR_UNMERGED(p))
+               run_external_diff(name, NULL, NULL, NULL, NULL);
+       else
+               run_external_diff(name, other, p->one, p->two, msg);
+}
+
+int diff_needs_to_stay(struct diff_queue_struct *q, int i,
+                      struct diff_filespec *it)
+{
+       /* If it will be used in later entry (either stay or used
+        * as the source of rename/copy), we need to copy, not rename.
+        */
+       while (i < q->nr) {
+               struct diff_filepair *p = q->queue[i++];
+               if (!DIFF_FILE_VALID(p->two))
+                       continue; /* removed is fine */
+               if (strcmp(p->one->path, it->path))
+                       continue; /* not relevant */
+
+               /* p has its src set to *it and it is not a delete;
+                * it will be used for in-place change, rename/copy,
+                * or just stays there.  We cannot rename it out.
+                */
+               return 1;
+       }
+       return 0;
+}
+
+static int diff_used_as_source(struct diff_queue_struct *q, int lim,
+                              struct diff_filespec *it)
+{
+       int i;
+       for (i = 0; i < lim; i++) {
+               struct diff_filepair *p = q->queue[i++];
+               if (!strcmp(p->one->path, it->path))
+                       return 1;
+       }
+       return 0;
+}
+
 void diffcore_prune(void)
 {
        /*
         * Although rename/copy detection wants to have "no-change"
         * entries fed into them, the downstream do not need to see
-        * them.  This function removes such entries.
+        * them, unless we had rename/copy for the same path earlier.
+        * This function removes such entries.
         *
         * The applications that use rename/copy should:
         *
@@ -585,6 +621,7 @@ void diffcore_prune(void)
         * (3) call diffcore_prune
         * (4) call other diffcore_xxx that do not need to see
         *     "no-change" entries.
+        * (5) call diff_flush().
         */
        struct diff_queue_struct *q = &diff_queued_diff;
        struct diff_queue_struct outq;
@@ -595,22 +632,21 @@ void diffcore_prune(void)
 
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
-               if (!uninteresting(p))
+               if (!diff_unmodified_pair(p) ||
+                   diff_used_as_source(q, i, p->one))
                        diff_q(&outq, p);
                else
-                       diff_free_filepair(p);
+                       free(p);
        }
        free(q->queue);
        *q = outq;
        return;
 }
 
-static void diff_flush_one(struct diff_filepair *p)
+static void diff_flush_one(struct diff_filepair *p, const char *msg)
 {
-       if (uninteresting(p))
-               return;
        if (generate_patch)
-               diff_flush_patch(p);
+               diff_flush_patch(p, msg);
        else
                diff_flush_raw(p);
 }
@@ -618,14 +654,7 @@ static void diff_flush_one(struct diff_filepair *p)
 int diff_queue_is_empty(void)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
-       int i;
-
-       for (i = 0; i < q->nr; i++) {
-               struct diff_filepair *p = q->queue[i];
-               if (!uninteresting(p))
-                       return 0;
-       }
-       return 1;
+       return q->nr == 0;
 }
 
 void diff_flush(int diff_output_style)
@@ -646,13 +675,35 @@ void diff_flush(int diff_output_style)
                generate_patch = 1;
                break;
        }
-       for (i = 0; i < q->nr; i++)
-               diff_flush_one(q->queue[i]);
+       for (i = 0; i < q->nr; i++) {
+               char msg_[PATH_MAX*2+200], *msg = NULL;
+               struct diff_filepair *p = q->queue[i];
+               if (strcmp(p->one->path, p->two->path)) {
+                       /* This is rename or copy.  Which one is it? */
+                       if (diff_needs_to_stay(q, i+1, p->one)) {
+                               sprintf(msg_,
+                                       "similarity index %d%%\n"
+                                       "copy from %s\n"
+                                       "copy to %s\n",
+                                       (int)(0.5 + p->score * 100/MAX_SCORE),
+                                       p->one->path, p->two->path);
+                       }
+                       else
+                               sprintf(msg_,
+                                       "similarity index %d%%\n"
+                                       "rename old %s\n"
+                                       "rename new %s\n",
+                                       (int)(0.5 + p->score * 100/MAX_SCORE),
+                                       p->one->path, p->two->path);
+                       msg = msg_;
+               }
+               diff_flush_one(p, msg);
+       }
+
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
                diff_free_filespec_data(p->one);
                diff_free_filespec_data(p->two);
-               free(p->xfrm_msg);
                free(p);
        }
        free(q->queue);
@@ -674,10 +725,10 @@ void diff_addremove(int addremove, unsigned mode,
         * entries to the diff-core.  They will be prefixed
         * with something like '=' or '*' (I haven't decided
         * which but should not make any difference).
-        * Feeding the same new and old to diff_change() should
-        * also have the same effect.  diff_flush() should
-        * filter uninteresting ones out at the final output
-        * stage.
+        * Feeding the same new and old to diff_change() 
+        * also has the same effect.  diffcore_prune() should
+        * be used to filter uninteresting ones out before the
+        * final output happens.
         */
        if (reverse_diff)
                addremove = (addremove == '+' ? '-' :