[PATCH] Redo rename/copy detection logic.
[git/git.git] / diffcore-rename.c
index f40ab78..34e83da 100644 (file)
@@ -6,29 +6,92 @@
 #include "diffcore.h"
 #include "delta.h"
 
-struct diff_rename_pool {
-       struct diff_filespec **s;
-       int nr, alloc;
-};
+/* Table of rename/copy destinations */
+
+static struct diff_rename_dst {
+       struct diff_filespec *two;
+       struct diff_filepair *pair;
+} *rename_dst;
+static int rename_dst_nr, rename_dst_alloc;
 
-static void diff_rename_pool_clear(struct diff_rename_pool *pool)
+static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
+                                                int insert_ok)
 {
-       pool->s = NULL; pool->nr = pool->alloc = 0;
+       int first, last;
+
+       first = 0;
+       last = rename_dst_nr;
+       while (last > first) {
+               int next = (last + first) >> 1;
+               struct diff_rename_dst *dst = &(rename_dst[next]);
+               int cmp = strcmp(two->path, dst->two->path);
+               if (!cmp)
+                       return dst;
+               if (cmp < 0) {
+                       last = next;
+                       continue;
+               }
+               first = next+1;
+       }
+       /* not found */
+       if (!insert_ok)
+               return NULL;
+       /* insert to make it at "first" */
+       if (rename_dst_alloc <= rename_dst_nr) {
+               rename_dst_alloc = alloc_nr(rename_dst_alloc);
+               rename_dst = xrealloc(rename_dst,
+                                     rename_dst_alloc * sizeof(*rename_dst));
+       }
+       rename_dst_nr++;
+       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].pair = NULL;
+       return &(rename_dst[first]);
 }
 
-static void diff_rename_pool_add(struct diff_rename_pool *pool,
-                                struct diff_filespec *s)
-{
-       if (S_ISDIR(s->mode))
-               return;  /* no trees, please */
+static struct diff_rename_src {
+       struct diff_filespec *one;
+       unsigned src_used : 1;
+} *rename_src;
+static int rename_src_nr, rename_src_alloc;
 
-       if (pool->alloc <= pool->nr) {
-               pool->alloc = alloc_nr(pool->alloc);
-               pool->s = xrealloc(pool->s,
-                                  sizeof(*(pool->s)) * pool->alloc);
+static struct diff_rename_src *locate_rename_src(struct diff_filespec *one,
+                                                int insert_ok)
+{
+       int first, last;
+
+       first = 0;
+       last = rename_src_nr;
+       while (last > first) {
+               int next = (last + first) >> 1;
+               struct diff_rename_src *src = &(rename_src[next]);
+               int cmp = strcmp(one->path, src->one->path);
+               if (!cmp)
+                       return src;
+               if (cmp < 0) {
+                       last = next;
+                       continue;
+               }
+               first = next+1;
+       }
+       /* not found */
+       if (!insert_ok)
+               return NULL;
+       /* insert to make it at "first" */
+       if (rename_src_alloc <= rename_src_nr) {
+               rename_src_alloc = alloc_nr(rename_src_alloc);
+               rename_src = xrealloc(rename_src,
+                                     rename_src_alloc * sizeof(*rename_src));
        }
-       pool->s[pool->nr] = s;
-       pool->nr++;
+       rename_src_nr++;
+       if (first < rename_src_nr)
+               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_used = 0;
+       return &(rename_src[first]);
 }
 
 static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst)
@@ -46,8 +109,8 @@ static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst)
 }
 
 struct diff_score {
-       struct diff_filespec *src;
-       struct diff_filespec *dst;
+       int src; /* index in rename_src */
+       int dst; /* index in rename_dst */
        int score;
        int rank;
 };
@@ -113,92 +176,28 @@ static int estimate_similarity(struct diff_filespec *src,
        return score;
 }
 
-static void record_rename_pair(struct diff_queue_struct *outq,
-                              struct diff_filespec *src,
-                              struct diff_filespec *dst,
-                              int rank,
-                              int score)
+static void record_rename_pair(struct diff_queue_struct *renq,
+                              int dst_index, int src_index, int score)
 {
-       /*
-        * These ranks are used to sort the final output, because there
-        * are certain dependencies:
-        *
-        *  1. rename/copy that depends on deleted ones.
-        *  2. deletions in the original.
-        *  3. rename/copy that depends on the pre-edit image of kept files.
-        *  4. additions, modifications and no-modifications in the original.
-        *  5. rename/copy that depends on the post-edit image of kept files
-        *     (note that we currently do not detect such rename/copy).
-        *
-        * The downstream diffcore transformers are free to reorder
-        * the entries as long as they keep file pairs that has the
-        * same p->one->path in earlier rename_rank to appear before
-        * later ones.
-        *
-        * To the final output routine, and in the diff-raw format
-        * output, a rename/copy that is based on a path that has a
-        * later entry that shares the same p->one->path and is not a
-        * deletion is a copy.  Otherwise it is a rename.
-        */
+       struct diff_filespec *one, *two, *src, *dst;
+       struct diff_filepair *dp;
 
-       struct diff_filepair *dp = diff_queue(outq, src, dst);
-       dp->rename_rank = rank * 2 + 1;
-       dp->score = score;
-       dst->xfrm_flags |= RENAME_DST_MATCHED;
-}
+       if (rename_dst[dst_index].pair)
+               die("internal error: dst already matched.");
 
-#if 0
-static void debug_filespec(struct diff_filespec *s, int x, const char *one)
-{
-       fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
-               x, one,
-               s->path,
-               DIFF_FILE_VALID(s) ? "valid" : "invalid",
-               s->mode,
-               s->sha1_valid ? sha1_to_hex(s->sha1) : "");
-       fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
-               x, one,
-               s->size, s->xfrm_flags);
-}
+       src = rename_src[src_index].one;
+       one = alloc_filespec(src->path);
+       fill_filespec(one, src->sha1, src->mode);
 
-static void debug_filepair(const struct diff_filepair *p, int i)
-{
-       debug_filespec(p->one, i, "one");
-       debug_filespec(p->two, i, "two");
-       fprintf(stderr, "pair rank %d, orig order %d, score %d\n",
-               p->rename_rank, p->orig_order, p->score);
-}
+       dst = rename_dst[dst_index].two;
+       two = alloc_filespec(dst->path);
+       fill_filespec(two, dst->sha1, dst->mode);
 
-static void debug_queue(const char *msg, struct diff_queue_struct *q)
-{
-       int i;
-       if (msg)
-               fprintf(stderr, "%s\n", msg);
-       fprintf(stderr, "q->nr = %d\n", q->nr);
-       for (i = 0; i < q->nr; i++) {
-               struct diff_filepair *p = q->queue[i];
-               debug_filepair(p, i);
-       }
-}
-#else
-#define debug_queue(a,b) do { ; /*nothing*/ } while(0)
-#endif
+       dp = diff_queue(renq, one, two);
+       dp->score = score;
 
-/*
- * We sort the outstanding diff entries according to the rank (see
- * comment at the beginning of record_rename_pair) and tiebreak with
- * the order in the original input.
- */
-static int rank_compare(const void *a_, const void *b_)
-{
-       const struct diff_filepair *a = *(const struct diff_filepair **)a_;
-       const struct diff_filepair *b = *(const struct diff_filepair **)b_;
-       int a_rank = a->rename_rank;
-       int b_rank = b->rename_rank;
-
-       if (a_rank != b_rank)
-               return a_rank - b_rank;
-       return a->orig_order - b->orig_order;
+       rename_src[src_index].src_used = 1;
+       rename_dst[dst_index].pair = dp;
 }
 
 /*
@@ -232,24 +231,15 @@ int diff_scoreopt_parse(const char *opt)
 void diffcore_rename(int detect_rename, int minimum_score)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
-       struct diff_queue_struct outq;
-       struct diff_rename_pool created, deleted, stay;
-       struct diff_rename_pool *(srcs[2]);
+       struct diff_queue_struct renq, outq;
        struct diff_score *mx;
-       int h, i, j;
-       int num_create, num_src, dst_cnt, src_cnt;
+       int i, j;
+       int num_create, num_src, dst_cnt;
 
        if (!minimum_score)
                minimum_score = DEFAULT_MINIMUM_SCORE;
-       outq.queue = NULL;
-       outq.nr = outq.alloc = 0;
-
-       diff_rename_pool_clear(&created);
-       diff_rename_pool_clear(&deleted);
-       diff_rename_pool_clear(&stay);
-
-       srcs[0] = &deleted;
-       srcs[1] = &stay;
+       renq.queue = NULL;
+       renq.nr = renq.alloc = 0;
 
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
@@ -257,76 +247,70 @@ void diffcore_rename(int detect_rename, int minimum_score)
                        if (!DIFF_FILE_VALID(p->two))
                                continue; /* unmerged */
                        else
-                               diff_rename_pool_add(&created, p->two);
+                               locate_rename_dst(p->two, 1);
                else if (!DIFF_FILE_VALID(p->two))
-                       diff_rename_pool_add(&deleted, p->one);
+                       locate_rename_src(p->one, 1);
                else if (1 < detect_rename) /* find copy, too */
-                       diff_rename_pool_add(&stay, p->one);
+                       locate_rename_src(p->one, 1);
        }
-       if (created.nr == 0)
+       if (rename_dst_nr == 0)
                goto cleanup; /* nothing to do */
 
        /* We really want to cull the candidates list early
         * with cheap tests in order to avoid doing deltas.
         */
-       for (i = 0; i < created.nr; i++) {
-               for (h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) {
-                       struct diff_rename_pool *p = srcs[h];
-                       for (j = 0; j < p->nr; j++) {
-                               if (!is_exact_match(p->s[j], created.s[i]))
-                                       continue;
-                               record_rename_pair(&outq,
-                                                  p->s[j], created.s[i], h,
-                                                  MAX_SCORE);
-                               break; /* we are done with this entry */
-                       }
+       for (i = 0; i < rename_dst_nr; i++) {
+               struct diff_filespec *two = rename_dst[i].two;
+               for (j = 0; j < rename_src_nr; j++) {
+                       struct diff_filespec *one = rename_src[j].one;
+                       if (!is_exact_match(one, two))
+                               continue;
+                       record_rename_pair(&renq, i, j, MAX_SCORE);
+                       break; /* we are done with this entry */
                }
        }
-       debug_queue("done detecting exact", &outq);
+       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 (outq.nr == created.nr)
+       if (renq.nr == rename_dst_nr)
                goto flush_rest;
 
-       num_create = (created.nr - outq.nr);
-       num_src = deleted.nr + stay.nr;
+       num_create = (rename_dst_nr - renq.nr);
+       num_src = rename_src_nr;
        mx = xmalloc(sizeof(*mx) * num_create * num_src);
-       for (dst_cnt = i = 0; i < created.nr; i++) {
+       for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
                int base = dst_cnt * num_src;
-               if (created.s[i]->xfrm_flags & RENAME_DST_MATCHED)
+               struct diff_filespec *two = rename_dst[i].two;
+               if (rename_dst[i].pair)
                        continue; /* dealt with exact match already. */
-               for (src_cnt = h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) {
-                       struct diff_rename_pool *p = srcs[h];
-                       for (j = 0; j < p->nr; j++, src_cnt++) {
-                               struct diff_score *m = &mx[base + src_cnt];
-                               m->src = p->s[j];
-                               m->dst = created.s[i];
-                               m->score = estimate_similarity(m->src, m->dst,
-                                                              minimum_score);
-                               m->rank = h;
-                       }
+               for (j = 0; j < rename_src_nr; j++) {
+                       struct diff_filespec *one = rename_src[j].one;
+                       struct diff_score *m = &mx[base+j];
+                       m->src = j;
+                       m->dst = i;
+                       m->score = estimate_similarity(one, two,
+                                                      minimum_score);
                }
                dst_cnt++;
        }
        /* cost matrix sorted by most to least similar pair */
        qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
        for (i = 0; i < num_create * num_src; i++) {
-               if (mx[i].dst->xfrm_flags & RENAME_DST_MATCHED)
-                       continue; /* alreayd done, either exact or fuzzy. */
+               struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
+               if (dst->pair)
+                       continue; /* already done, either exact or fuzzy. */
                if (mx[i].score < minimum_score)
                        break; /* there is not any more diffs applicable. */
-               record_rename_pair(&outq,
-                                 mx[i].src, mx[i].dst, mx[i].rank,
-                                 mx[i].score);
+               record_rename_pair(&renq, mx[i].dst, mx[i].src, mx[i].score);
        }
        free(mx);
-       debug_queue("done detecting fuzzy", &outq);
+       diff_debug_queue("done detecting fuzzy", &renq);
 
  flush_rest:
        /* At this point, we have found some renames and copies and they
-        * are kept in outq.  The original list is still in *q.
+        * are kept in renq.  The original list is still in *q.
         *
         * Scan the original list and move them into the outq; we will sort
         * outq and swap it into the queue supplied to pass that to
@@ -335,68 +319,61 @@ void diffcore_rename(int detect_rename, int minimum_score)
         * See comments at the top of record_rename_pair for numbers used
         * to assign rename_rank.
         */
+       outq.queue = NULL;
+       outq.nr = outq.alloc = 0;
        for (i = 0; i < q->nr; i++) {
-               struct diff_filepair *dp, *p = q->queue[i];
-               if (!DIFF_FILE_VALID(p->one)) {
-                       /* creation or unmerged entries */
-                       dp = diff_queue(&outq, p->one, p->two);
-                       dp->rename_rank = 4;
-               }
-               else if (!DIFF_FILE_VALID(p->two)) {
-                       /* deletion */
-                       dp = diff_queue(&outq, p->one, p->two);
-                       dp->rename_rank = 2;
+               struct diff_filepair *p = q->queue[i];
+               struct diff_rename_src *src = locate_rename_src(p->one, 0);
+               struct diff_rename_dst *dst = locate_rename_dst(p->two, 0);
+               struct diff_filepair *pair_to_free = NULL;
+
+               if (dst) {
+                       /* creation */
+                       if (dst->pair) {
+                               /* renq has rename/copy already to produce
+                                * this file, so we do not emit the creation
+                                * record in the output.
+                                */
+                               diff_q(&outq, dst->pair);
+                               pair_to_free = p;
+                       }
+                       else
+                               /* no matching rename/copy source, so record
+                                * this as a creation.
+                                */
+                               diff_q(&outq, p);
                }
+               else if (!diff_unmodified_pair(p))
+                       /* all the other cases need to be recorded as is */
+                       diff_q(&outq, p);
                else {
-                       /* modification, or stay as is */
-                       dp = diff_queue(&outq, p->one, p->two);
-                       dp->rename_rank = 4;
-               }
-               free(p);
-       }
-       debug_queue("done copying original", &outq);
-
-       /* Sort outq */
-       qsort(outq.queue, outq.nr, sizeof(outq.queue[0]), rank_compare);
-
-       debug_queue("done sorting", &outq);
-
-       free(q->queue);
-       q->nr = q->alloc = 0;
-       q->queue = NULL;
-
-       /* Copy it out to q, removing duplicates. */
-       for (i = 0; i < outq.nr; i++) {
-               struct diff_filepair *p = outq.queue[i];
-               if (!DIFF_FILE_VALID(p->one)) {
-                       /* created or unmerged */
-                       if (p->two->xfrm_flags & RENAME_DST_MATCHED)
-                               ; /* rename/copy created it already */
+                       /* unmodified pair needs to be recorded only if
+                        * it is used as the source of rename/copy
+                        */
+                       if (src && src->src_used)
+                               diff_q(&outq, p);
                        else
-                               diff_queue(q, p->one, p->two);
-               }
-               else if (!DIFF_FILE_VALID(p->two)) {
-                       /* deleted */
-                       diff_queue(q, p->one, p->two);
+                               pair_to_free = p;
                }
-               else if (strcmp(p->one->path, p->two->path)) {
-                       /* rename or copy */
-                       struct diff_filepair *dp =
-                               diff_queue(q, p->one, p->two);
-                       dp->score = p->score;
+               if (pair_to_free) {
+                       diff_free_filespec_data(pair_to_free->one);
+                       diff_free_filespec_data(pair_to_free->two);
+                       free(pair_to_free);
                }
-               else
-                       /* otherwise it is a modified (or "stay") entry */
-                       diff_queue(q, p->one, p->two);
-               free(p);
        }
+       diff_debug_queue("done copying original", &outq);
 
-       free(outq.queue);
-       debug_queue("done collapsing", q);
+       free(renq.queue);
+       free(q->queue);
+       *q = outq;
+       diff_debug_queue("done collapsing", q);
 
  cleanup:
-       free(created.s);
-       free(deleted.s);
-       free(stay.s);
+       free(rename_dst);
+       rename_dst = NULL;
+       rename_dst_nr = rename_dst_alloc = 0;
+       free(rename_src);
+       rename_src = NULL;
+       rename_src_nr = rename_src_alloc = 0;
        return;
 }