summaryrefslogtreecommitdiff
path: root/diffcore-rename.c
diff options
context:
space:
mode:
Diffstat (limited to 'diffcore-rename.c')
-rw-r--r--diffcore-rename.c614
1 files changed, 614 insertions, 0 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c
new file mode 100644
index 0000000000..31941bcbbf
--- /dev/null
+++ b/diffcore-rename.c
@@ -0,0 +1,614 @@
+/*
+ * Copyright (C) 2005 Junio C Hamano
+ */
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "hash.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 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_filespec *one,
+ unsigned short score)
+{
+ 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].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 */
+ int score;
+ int name_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.
+ */
+ unsigned long max_size, 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;
+
+ /*
+ * 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(src, 0))
+ return 0;
+ if (!dst->cnt_data && diff_populate_filespec(dst, 0))
+ 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 (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
+ return 0;
+
+ delta_limit = (unsigned long)
+ (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
+ if (diffcore_count_changes(src, dst,
+ &src->cnt_data, &dst->cnt_data,
+ delta_limit,
+ &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].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_;
+
+ if (a->score == b->score)
+ return b->name_score - a->name_score;
+
+ return b->score - a->score;
+}
+
+struct file_similarity {
+ int src_dst, index;
+ struct diff_filespec *filespec;
+ struct file_similarity *next;
+};
+
+static int find_identical_files(struct file_similarity *src,
+ struct file_similarity *dst)
+{
+ int renames = 0;
+
+ /*
+ * Walk over all the destinations ...
+ */
+ do {
+ struct diff_filespec *target = dst->filespec;
+ struct file_similarity *p, *best;
+ int i = 100, best_score = -1;
+
+ /*
+ * .. to find the best source match
+ */
+ best = NULL;
+ for (p = src; p; p = p->next) {
+ int score;
+ struct diff_filespec *source = p->filespec;
+
+ /* False hash collission? */
+ if (hashcmp(source->sha1, target->sha1))
+ 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;
+ 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++;
+ }
+ } while ((dst = dst->next) != NULL);
+ return renames;
+}
+
+static void free_similarity_list(struct file_similarity *p)
+{
+ while (p) {
+ struct file_similarity *entry = p;
+ p = p->next;
+ free(entry);
+ }
+}
+
+static int find_same_files(void *ptr)
+{
+ int ret;
+ struct file_similarity *p = ptr;
+ struct file_similarity *src = NULL, *dst = NULL;
+
+ /* Split the hash list up into sources and destinations */
+ do {
+ struct file_similarity *entry = p;
+ p = p->next;
+ if (entry->src_dst < 0) {
+ entry->next = src;
+ src = entry;
+ } else {
+ entry->next = dst;
+ dst = entry;
+ }
+ } while (p);
+
+ /*
+ * If we have both sources *and* destinations, see if
+ * we can match them up
+ */
+ ret = (src && dst) ? find_identical_files(src, dst) : 0;
+
+ /* Free the hashes and return the number of renames found */
+ free_similarity_list(src);
+ free_similarity_list(dst);
+ return ret;
+}
+
+static unsigned int hash_filespec(struct diff_filespec *filespec)
+{
+ unsigned int hash;
+ if (!filespec->sha1_valid) {
+ if (diff_populate_filespec(filespec, 0))
+ return 0;
+ hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
+ }
+ memcpy(&hash, filespec->sha1, sizeof(hash));
+ return hash;
+}
+
+static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
+{
+ void **pos;
+ unsigned int hash;
+ struct file_similarity *entry = xmalloc(sizeof(*entry));
+
+ entry->src_dst = src_dst;
+ entry->index = index;
+ entry->filespec = filespec;
+ entry->next = NULL;
+
+ hash = hash_filespec(filespec);
+ pos = insert_hash(hash, entry, table);
+
+ /* We already had an entry there? */
+ if (pos) {
+ entry->next = *pos;
+ *pos = 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(void)
+{
+ int i;
+ struct hash_table file_table;
+
+ init_hash(&file_table);
+ for (i = 0; i < rename_src_nr; i++)
+ insert_file_table(&file_table, -1, i, rename_src[i].one);
+
+ for (i = 0; i < rename_dst_nr; i++)
+ insert_file_table(&file_table, 1, i, rename_dst[i].two);
+
+ /* Find the renames */
+ i = for_each_hash(&file_table, find_same_files);
+
+ /* .. and free the hash data structure */
+ free_hash(&file_table);
+
+ return i;
+}
+
+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;
+
+ 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
+ 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.
+ * 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->one, p->score);
+ }
+ 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->one, p->score);
+ }
+ }
+ 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();
+
+ /* 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);
+ num_src = rename_src_nr;
+
+ /* All done? */
+ if (!num_create)
+ goto cleanup;
+
+ /*
+ * 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
+ *
+ * but handles the potential overflow case specially (and we
+ * assume at least 32-bit integers)
+ */
+ if (rename_limit <= 0 || rename_limit > 32767)
+ rename_limit = 32767;
+ if ((num_create > rename_limit && num_src > rename_limit) ||
+ (num_create * num_src > rename_limit * rename_limit)) {
+ warning("too many files, skipping inexact rename detection");
+ goto cleanup;
+ }
+
+ 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);
+ m->name_score = basename_same(one, two);
+ diff_free_filespec_blob(one);
+ }
+ /* We do not need the text anymore */
+ diff_free_filespec_blob(two);
+ 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];
+ struct diff_filespec *src;
+ if (dst->pair)
+ continue; /* already done, either exact or fuzzy. */
+ if (mx[i].score < minimum_score)
+ break; /* there is no more usable pair. */
+ src = rename_src[mx[i].src].one;
+ if (src->rename_used)
+ continue;
+ record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
+ rename_count++;
+ }
+ 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 {
+ 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(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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 00:29:37 +0000