diff options
Diffstat (limited to 'third_party/git/diffcore-rename.c')
| -rw-r--r-- | third_party/git/diffcore-rename.c | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/third_party/git/diffcore-rename.c b/third_party/git/diffcore-rename.c new file mode 100644 index 0000000000..9624864858 --- /dev/null +++ b/third_party/git/diffcore-rename.c @@ -0,0 +1,684 @@ +/* + * Copyright (C) 2005 Junio C Hamano + */ +#include "cache.h" +#include "diff.h" +#include "diffcore.h" +#include "object-store.h" +#include "hashmap.h" +#include "progress.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 int find_rename_dst(struct diff_filespec *two) +{ + int first, last; + + first = 0; + last = rename_dst_nr; + while (last > first) { + int next = first + ((last - first) >> 1); + struct diff_rename_dst *dst = &(rename_dst[next]); + int cmp = strcmp(two->path, dst->two->path); + if (!cmp) + return next; + if (cmp < 0) { + last = next; + continue; + } + first = next+1; + } + return -first - 1; +} + +static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two) +{ + int ofs = find_rename_dst(two); + return ofs < 0 ? NULL : &rename_dst[ofs]; +} + +/* + * Returns 0 on success, -1 if we found a duplicate. + */ +static int add_rename_dst(struct diff_filespec *two) +{ + int first = find_rename_dst(two); + + if (first >= 0) + return -1; + first = -first - 1; + + /* insert to make it at "first" */ + ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc); + rename_dst_nr++; + if (first < rename_dst_nr) + MOVE_ARRAY(rename_dst + first + 1, rename_dst + first, + rename_dst_nr - first - 1); + rename_dst[first].two = alloc_filespec(two->path); + fill_filespec(rename_dst[first].two, &two->oid, two->oid_valid, + two->mode); + rename_dst[first].pair = NULL; + return 0; +} + +/* Table of rename/copy src files */ +static struct diff_rename_src { + struct diff_filepair *p; + unsigned short score; /* to remember the break score */ +} *rename_src; +static int rename_src_nr, rename_src_alloc; + +static struct diff_rename_src *register_rename_src(struct diff_filepair *p) +{ + int first, last; + struct diff_filespec *one = p->one; + unsigned short score = p->score; + + first = 0; + last = rename_src_nr; + while (last > first) { + int next = first + ((last - first) >> 1); + struct diff_rename_src *src = &(rename_src[next]); + int cmp = strcmp(one->path, src->p->one->path); + if (!cmp) + return src; + if (cmp < 0) { + last = next; + continue; + } + first = next+1; + } + + /* insert to make it at "first" */ + ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc); + rename_src_nr++; + if (first < rename_src_nr) + MOVE_ARRAY(rename_src + first + 1, rename_src + first, + rename_src_nr - first - 1); + rename_src[first].p = p; + rename_src[first].score = score; + return &(rename_src[first]); +} + +static int basename_same(struct diff_filespec *src, struct diff_filespec *dst) +{ + int src_len = strlen(src->path), dst_len = strlen(dst->path); + while (src_len && dst_len) { + char c1 = src->path[--src_len]; + char c2 = dst->path[--dst_len]; + if (c1 != c2) + return 0; + if (c1 == '/') + return 1; + } + return (!src_len || src->path[src_len - 1] == '/') && + (!dst_len || dst->path[dst_len - 1] == '/'); +} + +struct diff_score { + int src; /* index in rename_src */ + int dst; /* index in rename_dst */ + unsigned short score; + short name_score; +}; + +static int estimate_similarity(struct repository *r, + 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. + */ + unsigned long max_size, delta_size, base_size, src_copied, literal_added; + 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; + + /* + * Need to check that source and destination sizes are + * filled in before comparing them. + * + * If we already have "cnt_data" filled in, we know it's + * all good (avoid checking the size for zero, as that + * is a possible size - we really should have a flag to + * say whether the size is valid or not!) + */ + if (!src->cnt_data && + diff_populate_filespec(r, src, CHECK_SIZE_ONLY)) + return 0; + if (!dst->cnt_data && + diff_populate_filespec(r, dst, CHECK_SIZE_ONLY)) + return 0; + + max_size = ((src->size > dst->size) ? src->size : dst->size); + base_size = ((src->size < dst->size) ? src->size : dst->size); + delta_size = max_size - base_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 (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) + return 0; + + if (!src->cnt_data && diff_populate_filespec(r, src, 0)) + return 0; + if (!dst->cnt_data && diff_populate_filespec(r, dst, 0)) + return 0; + + if (diffcore_count_changes(r, src, dst, + &src->cnt_data, &dst->cnt_data, + &src_copied, &literal_added)) + return 0; + + /* How similar are they? + * what percentage of material in dst are from source? + */ + if (!dst->size) + score = 0; /* should not happen */ + else + score = (int)(src_copied * MAX_SCORE / max_size); + return score; +} + +static void record_rename_pair(int dst_index, int src_index, int score) +{ + struct diff_filespec *src, *dst; + struct diff_filepair *dp; + + if (rename_dst[dst_index].pair) + die("internal error: dst already matched."); + + src = rename_src[src_index].p->one; + src->rename_used++; + src->count++; + + dst = rename_dst[dst_index].two; + dst->count++; + + dp = diff_queue(NULL, src, dst); + dp->renamed_pair = 1; + if (!strcmp(src->path, dst->path)) + dp->score = rename_src[src_index].score; + else + dp->score = score; + 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_; + + /* sink the unused ones to the bottom */ + if (a->dst < 0) + return (0 <= b->dst); + else if (b->dst < 0) + return -1; + + if (a->score == b->score) + return b->name_score - a->name_score; + + return b->score - a->score; +} + +struct file_similarity { + struct hashmap_entry entry; + int index; + struct diff_filespec *filespec; +}; + +static unsigned int hash_filespec(struct repository *r, + struct diff_filespec *filespec) +{ + if (!filespec->oid_valid) { + if (diff_populate_filespec(r, filespec, 0)) + return 0; + hash_object_file(filespec->data, filespec->size, "blob", + &filespec->oid); + } + return oidhash(&filespec->oid); +} + +static int find_identical_files(struct hashmap *srcs, + int dst_index, + struct diff_options *options) +{ + int renames = 0; + + struct diff_filespec *target = rename_dst[dst_index].two; + struct file_similarity *p, *best = NULL; + int i = 100, best_score = -1; + + /* + * Find the best source match for specified destination. + */ + p = hashmap_get_from_hash(srcs, + hash_filespec(options->repo, target), + NULL); + for (; p; p = hashmap_get_next(srcs, p)) { + int score; + struct diff_filespec *source = p->filespec; + + /* False hash collision? */ + if (!oideq(&source->oid, &target->oid)) + continue; + /* Non-regular files? If so, the modes must match! */ + if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) { + if (source->mode != target->mode) + continue; + } + /* Give higher scores to sources that haven't been used already */ + score = !source->rename_used; + if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY) + continue; + score += basename_same(source, target); + if (score > best_score) { + best = p; + best_score = score; + if (score == 2) + break; + } + + /* Too many identical alternatives? Pick one */ + if (!--i) + break; + } + if (best) { + record_rename_pair(dst_index, best->index, MAX_SCORE); + renames++; + } + return renames; +} + +static void insert_file_table(struct repository *r, + struct hashmap *table, int index, + struct diff_filespec *filespec) +{ + struct file_similarity *entry = xmalloc(sizeof(*entry)); + + entry->index = index; + entry->filespec = filespec; + + hashmap_entry_init(entry, hash_filespec(r, filespec)); + hashmap_add(table, entry); +} + +/* + * Find exact renames first. + * + * The first round matches up the up-to-date entries, + * and then during the second round we try to match + * cache-dirty entries as well. + */ +static int find_exact_renames(struct diff_options *options) +{ + int i, renames = 0; + struct hashmap file_table; + + /* Add all sources to the hash table in reverse order, because + * later on they will be retrieved in LIFO order. + */ + hashmap_init(&file_table, NULL, NULL, rename_src_nr); + for (i = rename_src_nr-1; i >= 0; i--) + insert_file_table(options->repo, + &file_table, i, + rename_src[i].p->one); + + /* Walk the destinations and find best source match */ + for (i = 0; i < rename_dst_nr; i++) + renames += find_identical_files(&file_table, i, options); + + /* Free the hash data structure and entries */ + hashmap_free(&file_table, 1); + + return renames; +} + +#define NUM_CANDIDATE_PER_DST 4 +static void record_if_better(struct diff_score m[], struct diff_score *o) +{ + int i, worst; + + /* find the worst one */ + worst = 0; + for (i = 1; i < NUM_CANDIDATE_PER_DST; i++) + if (score_compare(&m[i], &m[worst]) > 0) + worst = i; + + /* is it better than the worst one? */ + if (score_compare(&m[worst], o) > 0) + m[worst] = *o; +} + +/* + * Returns: + * 0 if we are under the limit; + * 1 if we need to disable inexact rename detection; + * 2 if we would be under the limit if we were given -C instead of -C -C. + */ +static int too_many_rename_candidates(int num_create, + struct diff_options *options) +{ + int rename_limit = options->rename_limit; + int num_src = rename_src_nr; + int i; + + options->needed_rename_limit = 0; + + /* + * This basically does a test for the rename matrix not + * growing larger than a "rename_limit" square matrix, ie: + * + * num_create * num_src > rename_limit * rename_limit + */ + if (rename_limit <= 0) + rename_limit = 32767; + if ((num_create <= rename_limit || num_src <= rename_limit) && + ((uint64_t)num_create * (uint64_t)num_src + <= (uint64_t)rename_limit * (uint64_t)rename_limit)) + return 0; + + options->needed_rename_limit = + num_src > num_create ? num_src : num_create; + + /* Are we running under -C -C? */ + if (!options->flags.find_copies_harder) + return 1; + + /* Would we bust the limit if we were running under -C? */ + for (num_src = i = 0; i < rename_src_nr; i++) { + if (diff_unmodified_pair(rename_src[i].p)) + continue; + num_src++; + } + if ((num_create <= rename_limit || num_src <= rename_limit) && + ((uint64_t)num_create * (uint64_t)num_src + <= (uint64_t)rename_limit * (uint64_t)rename_limit)) + return 2; + return 1; +} + +static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies) +{ + int count = 0, i; + + for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) { + struct diff_rename_dst *dst; + + if ((mx[i].dst < 0) || + (mx[i].score < minimum_score)) + break; /* there is no more usable pair. */ + dst = &rename_dst[mx[i].dst]; + if (dst->pair) + continue; /* already done, either exact or fuzzy. */ + if (!copies && rename_src[mx[i].src].p->one->rename_used) + continue; + record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); + count++; + } + return count; +} + +void diffcore_rename(struct diff_options *options) +{ + int detect_rename = options->detect_rename; + int minimum_score = options->rename_score; + struct diff_queue_struct *q = &diff_queued_diff; + struct diff_queue_struct outq; + struct diff_score *mx; + int i, j, rename_count, skip_unmodified = 0; + int num_create, dst_cnt; + struct progress *progress = NULL; + + if (!minimum_score) + minimum_score = DEFAULT_RENAME_SCORE; + + 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 if (options->single_follow && + strcmp(options->single_follow, p->two->path)) + continue; /* not interested */ + else if (!options->flags.rename_empty && + is_empty_blob_oid(&p->two->oid)) + continue; + else if (add_rename_dst(p->two) < 0) { + warning("skipping rename detection, detected" + " duplicate destination '%s'", + p->two->path); + goto cleanup; + } + } + else if (!options->flags.rename_empty && + is_empty_blob_oid(&p->one->oid)) + continue; + else if (!DIFF_PAIR_UNMERGED(p) && !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. + * So we increment the "rename_used" score + * by one, to indicate ourselves as a user + */ + if (p->broken_pair && !p->score) + p->one->rename_used++; + register_rename_src(p); + } + else if (detect_rename == DIFF_DETECT_COPY) { + /* + * Increment the "rename_used" score by + * one, to indicate ourselves as a user. + */ + p->one->rename_used++; + register_rename_src(p); + } + } + if (rename_dst_nr == 0 || rename_src_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. + */ + rename_count = find_exact_renames(options); + + /* Did we only want exact renames? */ + if (minimum_score == MAX_SCORE) + goto cleanup; + + /* + * Calculate how many renames are left (but all the source + * files still remain as options for rename/copies!) + */ + num_create = (rename_dst_nr - rename_count); + + /* All done? */ + if (!num_create) + goto cleanup; + + switch (too_many_rename_candidates(num_create, options)) { + case 1: + goto cleanup; + case 2: + options->degraded_cc_to_c = 1; + skip_unmodified = 1; + break; + default: + break; + } + + if (options->show_rename_progress) { + progress = start_delayed_progress( + _("Performing inexact rename detection"), + (uint64_t)rename_dst_nr * (uint64_t)rename_src_nr); + } + + mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_create), sizeof(*mx)); + for (dst_cnt = i = 0; i < rename_dst_nr; i++) { + struct diff_filespec *two = rename_dst[i].two; + struct diff_score *m; + + if (rename_dst[i].pair) + continue; /* dealt with exact match already. */ + + m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST]; + for (j = 0; j < NUM_CANDIDATE_PER_DST; j++) + m[j].dst = -1; + + for (j = 0; j < rename_src_nr; j++) { + struct diff_filespec *one = rename_src[j].p->one; + struct diff_score this_src; + + if (skip_unmodified && + diff_unmodified_pair(rename_src[j].p)) + continue; + + this_src.score = estimate_similarity(options->repo, + one, two, + minimum_score); + this_src.name_score = basename_same(one, two); + this_src.dst = i; + this_src.src = j; + record_if_better(m, &this_src); + /* + * Once we run estimate_similarity, + * We do not need the text anymore. + */ + diff_free_filespec_blob(one); + diff_free_filespec_blob(two); + } + dst_cnt++; + display_progress(progress, (uint64_t)(i+1)*(uint64_t)rename_src_nr); + } + stop_progress(&progress); + + /* cost matrix sorted by most to least similar pair */ + QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); + + rename_count += find_renames(mx, dst_cnt, minimum_score, 0); + if (detect_rename == DIFF_DETECT_COPY) + rename_count += find_renames(mx, dst_cnt, minimum_score, 1); + 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. + */ + DIFF_QUEUE_CLEAR(&outq); + for (i = 0; i < q->nr; i++) { + struct diff_filepair *p = q->queue[i]; + struct diff_filepair *pair_to_free = NULL; + + if (DIFF_PAIR_UNMERGED(p)) { + diff_q(&outq, p); + } + else 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); + 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); + if (dst && dst->pair) + /* counterpart is now rename/copy */ + pair_to_free = p; + } + else { + if (p->one->rename_used) + /* 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); + + for (i = 0; i < rename_dst_nr; i++) + free_filespec(rename_dst[i].two); + + FREE_AND_NULL(rename_dst); + rename_dst_nr = rename_dst_alloc = 0; + FREE_AND_NULL(rename_src); + rename_src_nr = rename_src_alloc = 0; + return; +} |