rebase: one safety net, one bugfix and one optimization.
[gitweb.git] / diffcore-rename.c
index 8fb45f0b8706baa6a1190b21d723d0b0d81203c5..dba965c0b4006251b1da04465d319c5fe9997ea4 100644 (file)
@@ -47,7 +47,8 @@ static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
        if (first < rename_dst_nr)
                memmove(rename_dst + first + 1, rename_dst + first,
                        (rename_dst_nr - first - 1) * sizeof(*rename_dst));
-       rename_dst[first].two = two;
+       rename_dst[first].two = alloc_filespec(two->path);
+       fill_filespec(rename_dst[first].two, two->sha1, two->mode);
        rename_dst[first].pair = NULL;
        return &(rename_dst[first]);
 }
@@ -55,12 +56,12 @@ static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
 /* Table of rename/copy src files */
 static struct diff_rename_src {
        struct diff_filespec *one;
-       unsigned src_stays : 1;
+       unsigned src_path_left : 1;
 } *rename_src;
 static int rename_src_nr, rename_src_alloc;
 
 static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
-                                                  int src_stays)
+                                                  int src_path_left)
 {
        int first, last;
 
@@ -90,7 +91,7 @@ static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
                memmove(rename_src + first + 1, rename_src + first,
                        (rename_src_nr - first - 1) * sizeof(*rename_src));
        rename_src[first].one = one;
-       rename_src[first].src_stays = src_stays;
+       rename_src[first].src_path_left = src_path_left;
        return &(rename_src[first]);
 }
 
@@ -136,6 +137,7 @@ static int estimate_similarity(struct diff_filespec *src,
         */
        void *delta;
        unsigned long delta_size, base_size, src_copied, literal_added;
+       unsigned long delta_limit;
        int score;
 
        /* We deal only with regular files.  Symlink renames are handled
@@ -163,9 +165,13 @@ static int estimate_similarity(struct diff_filespec *src,
        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
                return 0; /* error but caught downstream */
 
+       delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
        delta = diff_delta(src->data, src->size,
                           dst->data, dst->size,
-                          &delta_size);
+                          &delta_size, delta_limit);
+       if (!delta)
+               /* If delta_limit is exceeded, we have too much differences */
+               return 0;
 
        /* A delta that has a lot of literal additions would have
         * big delta_size no matter what else it does.
@@ -196,8 +202,7 @@ static int estimate_similarity(struct diff_filespec *src,
        return score;
 }
 
-static void record_rename_pair(struct diff_queue_struct *renq,
-                              int dst_index, int src_index, int score)
+static void record_rename_pair(int dst_index, int src_index, int score)
 {
        struct diff_filespec *one, *two, *src, *dst;
        struct diff_filepair *dp;
@@ -213,9 +218,9 @@ static void record_rename_pair(struct diff_queue_struct *renq,
        two = alloc_filespec(dst->path);
        fill_filespec(two, dst->sha1, dst->mode);
 
-       dp = diff_queue(renq, one, two);
+       dp = diff_queue(NULL, one, two);
        dp->score = score;
-       dp->source_stays = rename_src[src_index].src_stays;
+       dp->source_stays = rename_src[src_index].src_path_left;
        rename_dst[dst_index].pair = dp;
 }
 
@@ -229,18 +234,35 @@ static int score_compare(const void *a_, const void *b_)
        return b->score - a->score;
 }
 
-void diffcore_rename(int detect_rename, int minimum_score)
+static int compute_stays(struct diff_queue_struct *q,
+                        struct diff_filespec *one)
 {
+       int i;
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               if (strcmp(one->path, p->two->path))
+                       continue;
+               if (DIFF_PAIR_RENAME(p)) {
+                       return 0; /* something else is renamed into this */
+               }
+       }
+       return 1;
+}
+
+void diffcore_rename(struct diff_options *options)
+{
+       int detect_rename = options->detect_rename;
+       int minimum_score = options->rename_score;
+       int rename_limit = options->rename_limit;
        struct diff_queue_struct *q = &diff_queued_diff;
-       struct diff_queue_struct renq, outq;
+       struct diff_queue_struct outq;
        struct diff_score *mx;
-       int i, j;
+       int i, j, rename_count;
        int num_create, num_src, dst_cnt;
 
        if (!minimum_score)
                minimum_score = DEFAULT_RENAME_SCORE;
-       renq.queue = NULL;
-       renq.nr = renq.alloc = 0;
+       rename_count = 0;
 
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
@@ -260,7 +282,8 @@ void diffcore_rename(int detect_rename, int minimum_score)
                else if (detect_rename == DIFF_DETECT_COPY)
                        register_rename_src(p->one, 1);
        }
-       if (rename_dst_nr == 0)
+       if (rename_dst_nr == 0 ||
+           (0 < rename_limit && rename_limit < rename_dst_nr))
                goto cleanup; /* nothing to do */
 
        /* We really want to cull the candidates list early
@@ -272,19 +295,22 @@ void diffcore_rename(int detect_rename, int minimum_score)
                        struct diff_filespec *one = rename_src[j].one;
                        if (!is_exact_match(one, two))
                                continue;
-                       record_rename_pair(&renq, i, j, MAX_SCORE);
+                       record_rename_pair(i, j, MAX_SCORE);
+                       rename_count++;
                        break; /* we are done with this entry */
                }
        }
-       diff_debug_queue("done detecting exact", &renq);
 
        /* Have we run out the created file pool?  If so we can avoid
         * doing the delta matrix altogether.
         */
-       if (renq.nr == rename_dst_nr)
+       if (rename_count == rename_dst_nr)
+               goto cleanup;
+
+       if (minimum_score == MAX_SCORE)
                goto cleanup;
 
-       num_create = (rename_dst_nr - renq.nr);
+       num_create = (rename_dst_nr - rename_count);
        num_src = rename_src_nr;
        mx = xmalloc(sizeof(*mx) * num_create * num_src);
        for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
@@ -310,14 +336,14 @@ void diffcore_rename(int detect_rename, int minimum_score)
                        continue; /* already done, either exact or fuzzy. */
                if (mx[i].score < minimum_score)
                        break; /* there is no more usable pair. */
-               record_rename_pair(&renq, mx[i].dst, mx[i].src, mx[i].score);
+               record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
+               rename_count++;
        }
        free(mx);
-       diff_debug_queue("done detecting fuzzy", &renq);
 
  cleanup:
        /* At this point, we have found some renames and copies and they
-        * are kept in renq.  The original list is still in *q.
+        * are recorded in rename_dst.  The original list is still in *q.
         */
        outq.queue = NULL;
        outq.nr = outq.alloc = 0;
@@ -352,9 +378,9 @@ void diffcore_rename(int detect_rename, int minimum_score)
                         *
                         * (1) this is a broken delete and the counterpart
                         *     broken create remains in the output; or
-                        * (2) this is not a broken delete, and renq does
-                        *     not have a rename/copy to move p->one->path
-                        *     out.
+                        * (2) this is not a broken delete, and rename_dst
+                        *     does not have a rename/copy to move p->one->path
+                        *     out of existence.
                         *
                         * Otherwise, the counterpart broken create
                         * has been turned into a rename-edit; or
@@ -370,11 +396,16 @@ void diffcore_rename(int detect_rename, int minimum_score)
                                        pair_to_free = p;
                        }
                        else {
-                               for (j = 0; j < renq.nr; j++)
-                                       if (!strcmp(renq.queue[j]->one->path,
-                                                   p->one->path))
-                                               break;
-                               if (j < renq.nr)
+                               for (j = 0; j < rename_dst_nr; j++) {
+                                       if (!rename_dst[j].pair)
+                                               continue;
+                                       if (strcmp(rename_dst[j].pair->
+                                                  one->path,
+                                                  p->one->path))
+                                               continue;
+                                       break;
+                               }
+                               if (j < rename_dst_nr)
                                        /* this path remains */
                                        pair_to_free = p;
                        }
@@ -396,11 +427,32 @@ void diffcore_rename(int detect_rename, int minimum_score)
        }
        diff_debug_queue("done copying original", &outq);
 
-       free(renq.queue);
        free(q->queue);
        *q = outq;
        diff_debug_queue("done collapsing", q);
 
+       /* We need to see which rename source really stays here;
+        * earlier we only checked if the path is left in the result,
+        * but even if a path remains in the result, if that is coming
+        * from copying something else on top of it, then the original
+        * source is lost and does not stay.
+        */
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               if (DIFF_PAIR_RENAME(p) && p->source_stays) {
+                       /* If one appears as the target of a rename-copy,
+                        * then mark p->source_stays = 0; otherwise
+                        * leave it as is.
+                        */
+                       p->source_stays = compute_stays(q, p->one);
+               }
+       }
+
+       for (i = 0; i < rename_dst_nr; i++) {
+               diff_free_filespec_data(rename_dst[i].two);
+               free(rename_dst[i].two);
+       }
+
        free(rename_dst);
        rename_dst = NULL;
        rename_dst_nr = rename_dst_alloc = 0;