| /* |
| * Copyright (C) 2005 Junio C Hamano |
| */ |
| #include "cache.h" |
| #include "diff.h" |
| #include "diffcore.h" |
| #include "delta.h" |
| #include "count-delta.h" |
| |
| /* 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 struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two, |
| int insert_ok) |
| { |
| 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 = alloc_filespec(two->path); |
| fill_filespec(rename_dst[first].two, two->sha1, two->mode); |
| rename_dst[first].pair = NULL; |
| return &(rename_dst[first]); |
| } |
| |
| /* Table of rename/copy src files */ |
| static struct diff_rename_src { |
| struct diff_filespec *one; |
| 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_path_left) |
| { |
| 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; |
| } |
| |
| /* 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)); |
| } |
| 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_path_left = src_path_left; |
| return &(rename_src[first]); |
| } |
| |
| static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst) |
| { |
| if (src->sha1_valid && dst->sha1_valid && |
| !memcmp(src->sha1, dst->sha1, 20)) |
| return 1; |
| if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1)) |
| return 0; |
| if (src->size != dst->size) |
| return 0; |
| if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) |
| return 0; |
| if (src->size == dst->size && |
| !memcmp(src->data, dst->data, src->size)) |
| return 1; |
| return 0; |
| } |
| |
| struct diff_score { |
| int src; /* index in rename_src */ |
| int dst; /* index in rename_dst */ |
| int score; |
| }; |
| |
| static int estimate_similarity(struct diff_filespec *src, |
| struct diff_filespec *dst, |
| int minimum_score) |
| { |
| /* src points at a file that existed in the original tree (or |
| * optionally a file in the destination tree) and dst points |
| * at a newly created file. They may be quite similar, in which |
| * case we want to say src is renamed to dst or src is copied into |
| * dst, and then some edit has been applied to dst. |
| * |
| * Compare them and return how similar they are, representing |
| * the score as an integer between 0 and MAX_SCORE. |
| * |
| * When there is an exact match, it is considered a better |
| * match than anything else; the destination does not even |
| * call into this function in that case. |
| */ |
| 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 |
| * only when they are exact matches --- in other words, no edits |
| * after renaming. |
| */ |
| if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) |
| return 0; |
| |
| delta_size = ((src->size < dst->size) ? |
| (dst->size - src->size) : (src->size - dst->size)); |
| base_size = ((src->size < dst->size) ? src->size : dst->size); |
| |
| /* We would not consider edits that change the file size so |
| * drastically. delta_size must be smaller than |
| * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). |
| * |
| * Note that base_size == 0 case is handled here already |
| * and the final score computation below would not have a |
| * divide-by-zero issue. |
| */ |
| if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) |
| return 0; |
| |
| 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_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. |
| */ |
| if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) |
| return 0; |
| |
| /* Estimate the edit size by interpreting delta. */ |
| if (count_delta(delta, delta_size, &src_copied, &literal_added)) { |
| free(delta); |
| return 0; |
| } |
| free(delta); |
| |
| /* Extent of damage */ |
| if (src->size + literal_added < src_copied) |
| delta_size = 0; |
| else |
| delta_size = (src->size - src_copied) + literal_added; |
| |
| /* |
| * Now we will give some score to it. 100% edit gets 0 points |
| * and 0% edit gets MAX_SCORE points. |
| */ |
| score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); |
| if (score < 0) return 0; |
| if (MAX_SCORE < score) return MAX_SCORE; |
| return 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; |
| |
| if (rename_dst[dst_index].pair) |
| die("internal error: dst already matched."); |
| |
| src = rename_src[src_index].one; |
| one = alloc_filespec(src->path); |
| fill_filespec(one, src->sha1, src->mode); |
| |
| dst = rename_dst[dst_index].two; |
| two = alloc_filespec(dst->path); |
| fill_filespec(two, dst->sha1, dst->mode); |
| |
| dp = diff_queue(NULL, one, two); |
| dp->score = score; |
| dp->source_stays = rename_src[src_index].src_path_left; |
| rename_dst[dst_index].pair = dp; |
| } |
| |
| /* |
| * We sort the rename similarity matrix with the score, in descending |
| * order (the most similar first). |
| */ |
| static int score_compare(const void *a_, const void *b_) |
| { |
| const struct diff_score *a = a_, *b = b_; |
| return b->score - a->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 outq; |
| struct diff_score *mx; |
| int i, j, rename_count; |
| int num_create, num_src, dst_cnt; |
| |
| if (!minimum_score) |
| minimum_score = DEFAULT_RENAME_SCORE; |
| rename_count = 0; |
| |
| for (i = 0; i < q->nr; i++) { |
| struct diff_filepair *p = q->queue[i]; |
| if (!DIFF_FILE_VALID(p->one)) |
| if (!DIFF_FILE_VALID(p->two)) |
| continue; /* unmerged */ |
| else |
| locate_rename_dst(p->two, 1); |
| else if (!DIFF_FILE_VALID(p->two)) { |
| /* If the source is a broken "delete", and |
| * they did not really want to get broken, |
| * that means the source actually stays. |
| */ |
| int stays = (p->broken_pair && !p->score); |
| register_rename_src(p->one, stays); |
| } |
| else if (detect_rename == DIFF_DETECT_COPY) |
| register_rename_src(p->one, 1); |
| } |
| 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 |
| * with cheap tests in order to avoid doing deltas. |
| */ |
| 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(i, j, MAX_SCORE); |
| rename_count++; |
| break; /* we are done with this entry */ |
| } |
| } |
| |
| /* Have we run out the created file pool? If so we can avoid |
| * doing the delta matrix altogether. |
| */ |
| if (rename_count == rename_dst_nr) |
| goto cleanup; |
| |
| if (minimum_score == MAX_SCORE) |
| goto cleanup; |
| |
| 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++) { |
| int base = dst_cnt * num_src; |
| struct diff_filespec *two = rename_dst[i].two; |
| if (rename_dst[i].pair) |
| continue; /* dealt with exact match already. */ |
| 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++) { |
| 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 no more usable pair. */ |
| record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); |
| rename_count++; |
| } |
| free(mx); |
| |
| cleanup: |
| /* At this point, we have found some renames and copies and they |
| * are recorded in rename_dst. The original list is still in *q. |
| */ |
| outq.queue = NULL; |
| outq.nr = outq.alloc = 0; |
| for (i = 0; i < q->nr; i++) { |
| struct diff_filepair *p = q->queue[i]; |
| struct diff_filepair *pair_to_free = NULL; |
| |
| if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { |
| /* |
| * Creation |
| * |
| * We would output this create record if it has |
| * not been turned into a rename/copy already. |
| */ |
| struct diff_rename_dst *dst = |
| locate_rename_dst(p->two, 0); |
| if (dst && dst->pair) { |
| 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_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { |
| /* |
| * Deletion |
| * |
| * We would output this delete record if: |
| * |
| * (1) this is a broken delete and the counterpart |
| * broken create remains in the output; or |
| * (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 |
| * delete did not have a matching create to |
| * begin with. |
| */ |
| if (DIFF_PAIR_BROKEN(p)) { |
| /* broken delete */ |
| struct diff_rename_dst *dst = |
| locate_rename_dst(p->one, 0); |
| if (dst && dst->pair) |
| /* counterpart is now rename/copy */ |
| pair_to_free = p; |
| } |
| else { |
| 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; |
| } |
| |
| if (pair_to_free) |
| ; |
| else |
| diff_q(&outq, p); |
| } |
| else if (!diff_unmodified_pair(p)) |
| /* all the usual ones need to be kept */ |
| diff_q(&outq, p); |
| else |
| /* no need to keep unmodified pairs */ |
| pair_to_free = p; |
| |
| if (pair_to_free) |
| diff_free_filepair(pair_to_free); |
| } |
| diff_debug_queue("done copying original", &outq); |
| |
| 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; |
| free(rename_src); |
| rename_src = NULL; |
| rename_src_nr = rename_src_alloc = 0; |
| return; |
| } |