diff options
Diffstat (limited to 'diffcore-rename.c')
| -rw-r--r-- | diffcore-rename.c | 1721 |
1 files changed, 1721 insertions, 0 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c new file mode 100644 index 0000000..5a6e2bc --- /dev/null +++ b/diffcore-rename.c @@ -0,0 +1,1721 @@ +/* + * + * Copyright (C) 2005 Junio C Hamano + */ +#include "git-compat-util.h" +#include "diff.h" +#include "diffcore.h" +#include "object-store-ll.h" +#include "hashmap.h" +#include "mem-pool.h" +#include "oid-array.h" +#include "progress.h" +#include "promisor-remote.h" +#include "string-list.h" +#include "strmap.h" +#include "trace2.h" + +/* Table of rename/copy destinations */ + +static struct diff_rename_dst { + struct diff_filepair *p; + struct diff_filespec *filespec_to_free; + int is_rename; /* false -> just a create; true -> rename or copy */ +} *rename_dst; +static int rename_dst_nr, rename_dst_alloc; +/* Mapping from break source pathname to break destination index */ +static struct strintmap *break_idx = NULL; + +static struct diff_rename_dst *locate_rename_dst(struct diff_filepair *p) +{ + /* Lookup by p->ONE->path */ + int idx = break_idx ? strintmap_get(break_idx, p->one->path) : -1; + return (idx == -1) ? NULL : &rename_dst[idx]; +} + +/* + * Returns 0 on success, -1 if we found a duplicate. + */ +static int add_rename_dst(struct diff_filepair *p) +{ + ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc); + rename_dst[rename_dst_nr].p = p; + rename_dst[rename_dst_nr].filespec_to_free = NULL; + rename_dst[rename_dst_nr].is_rename = 0; + rename_dst_nr++; + 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 void register_rename_src(struct diff_filepair *p) +{ + if (p->broken_pair) { + if (!break_idx) { + break_idx = xmalloc(sizeof(*break_idx)); + strintmap_init_with_options(break_idx, -1, NULL, 0); + } + strintmap_set(break_idx, p->one->path, rename_dst_nr); + } + + ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc); + rename_src[rename_src_nr].p = p; + rename_src[rename_src_nr].score = p->score; + rename_src_nr++; +} + +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; +}; + +struct inexact_prefetch_options { + struct repository *repo; + int skip_unmodified; +}; +static void inexact_prefetch(void *prefetch_options) +{ + struct inexact_prefetch_options *options = prefetch_options; + int i; + struct oid_array to_fetch = OID_ARRAY_INIT; + + for (i = 0; i < rename_dst_nr; i++) { + if (rename_dst[i].p->renamed_pair) + /* + * The loop in diffcore_rename() will not need these + * blobs, so skip prefetching. + */ + continue; /* already found exact match */ + diff_add_if_missing(options->repo, &to_fetch, + rename_dst[i].p->two); + } + for (i = 0; i < rename_src_nr; i++) { + if (options->skip_unmodified && + diff_unmodified_pair(rename_src[i].p)) + /* + * The loop in diffcore_rename() will not need these + * blobs, so skip prefetching. + */ + continue; + diff_add_if_missing(options->repo, &to_fetch, + rename_src[i].p->one); + } + promisor_remote_get_direct(options->repo, to_fetch.oid, to_fetch.nr); + oid_array_clear(&to_fetch); +} + +static int estimate_similarity(struct repository *r, + struct diff_filespec *src, + struct diff_filespec *dst, + int minimum_score, + struct diff_populate_filespec_options *dpf_opt) +{ + /* 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!) + */ + dpf_opt->check_size_only = 1; + + if (!src->cnt_data && + diff_populate_filespec(r, src, dpf_opt)) + return 0; + if (!dst->cnt_data && + diff_populate_filespec(r, dst, dpf_opt)) + 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; + + dpf_opt->check_size_only = 0; + + if (!src->cnt_data && diff_populate_filespec(r, src, dpf_opt)) + return 0; + if (!dst->cnt_data && diff_populate_filespec(r, dst, dpf_opt)) + 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_filepair *src = rename_src[src_index].p; + struct diff_filepair *dst = rename_dst[dst_index].p; + + if (dst->renamed_pair) + die("internal error: dst already matched."); + + src->one->rename_used++; + src->one->count++; + + rename_dst[dst_index].filespec_to_free = dst->one; + rename_dst[dst_index].is_rename = 1; + + dst->one = src->one; + dst->renamed_pair = 1; + if (!strcmp(dst->one->path, dst->two->path)) + dst->score = rename_src[src_index].score; + else + dst->score = score; +} + +/* + * 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, NULL)) + return 0; + hash_object_file(r->hash_algo, filespec->data, filespec->size, + OBJ_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].p->two; + struct file_similarity *p, *best = NULL; + int i = 100, best_score = -1; + unsigned int hash = hash_filespec(options->repo, target); + + /* + * Find the best source match for specified destination. + */ + p = hashmap_get_entry_from_hash(srcs, hash, NULL, + struct file_similarity, entry); + hashmap_for_each_entry_from(srcs, p, entry) { + 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 mem_pool *pool, + struct hashmap *table, int index, + struct diff_filespec *filespec) +{ + struct file_similarity *entry = mem_pool_alloc(pool, sizeof(*entry)); + + entry->index = index; + entry->filespec = filespec; + + hashmap_entry_init(&entry->entry, hash_filespec(r, filespec)); + hashmap_add(table, &entry->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, + struct mem_pool *pool) +{ + 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, pool, + &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 (entries will be freed with the pool) */ + hashmap_clear(&file_table); + + return renames; +} + +struct dir_rename_info { + struct strintmap idx_map; + struct strmap dir_rename_guess; + struct strmap *dir_rename_count; + struct strintmap *relevant_source_dirs; + unsigned setup; +}; + +static char *get_dirname(const char *filename) +{ + char *slash = strrchr(filename, '/'); + return slash ? xstrndup(filename, slash - filename) : xstrdup(""); +} + +static void dirname_munge(char *filename) +{ + char *slash = strrchr(filename, '/'); + if (!slash) + slash = filename; + *slash = '\0'; +} + +static const char *get_highest_rename_path(struct strintmap *counts) +{ + int highest_count = 0; + const char *highest_destination_dir = NULL; + struct hashmap_iter iter; + struct strmap_entry *entry; + + strintmap_for_each_entry(counts, &iter, entry) { + const char *destination_dir = entry->key; + intptr_t count = (intptr_t)entry->value; + if (count > highest_count) { + highest_count = count; + highest_destination_dir = destination_dir; + } + } + return highest_destination_dir; +} + +static char *UNKNOWN_DIR = "/"; /* placeholder -- short, illegal directory */ + +static int dir_rename_already_determinable(struct strintmap *counts) +{ + struct hashmap_iter iter; + struct strmap_entry *entry; + int first = 0, second = 0, unknown = 0; + strintmap_for_each_entry(counts, &iter, entry) { + const char *destination_dir = entry->key; + intptr_t count = (intptr_t)entry->value; + if (!strcmp(destination_dir, UNKNOWN_DIR)) { + unknown = count; + } else if (count >= first) { + second = first; + first = count; + } else if (count >= second) { + second = count; + } + } + return first > second + unknown; +} + +static void increment_count(struct dir_rename_info *info, + char *old_dir, + char *new_dir) +{ + struct strintmap *counts; + struct strmap_entry *e; + + /* Get the {new_dirs -> counts} mapping using old_dir */ + e = strmap_get_entry(info->dir_rename_count, old_dir); + if (e) { + counts = e->value; + } else { + counts = xmalloc(sizeof(*counts)); + strintmap_init_with_options(counts, 0, NULL, 1); + strmap_put(info->dir_rename_count, old_dir, counts); + } + + /* Increment the count for new_dir */ + strintmap_incr(counts, new_dir, 1); +} + +static void update_dir_rename_counts(struct dir_rename_info *info, + struct strintmap *dirs_removed, + const char *oldname, + const char *newname) +{ + char *old_dir; + char *new_dir; + const char new_dir_first_char = newname[0]; + int first_time_in_loop = 1; + + if (!info->setup) + /* + * info->setup is 0 here in two cases: (1) all auxiliary + * vars (like dirs_removed) were NULL so + * initialize_dir_rename_info() returned early, or (2) + * either break detection or copy detection are active so + * that we never called initialize_dir_rename_info(). In + * the former case, we don't have enough info to know if + * directories were renamed (because dirs_removed lets us + * know about a necessary prerequisite, namely if they were + * removed), and in the latter, we don't care about + * directory renames or find_basename_matches. + * + * This matters because both basename and inexact matching + * will also call update_dir_rename_counts(). In either of + * the above two cases info->dir_rename_counts will not + * have been properly initialized which prevents us from + * updating it, but in these two cases we don't care about + * dir_rename_counts anyway, so we can just exit early. + */ + return; + + + old_dir = xstrdup(oldname); + new_dir = xstrdup(newname); + + while (1) { + int drd_flag = NOT_RELEVANT; + + /* Get old_dir, skip if its directory isn't relevant. */ + dirname_munge(old_dir); + if (info->relevant_source_dirs && + !strintmap_contains(info->relevant_source_dirs, old_dir)) + break; + + /* Get new_dir */ + dirname_munge(new_dir); + + /* + * When renaming + * "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c" + * then this suggests that both + * a/b/c/d/e/ => a/b/some/thing/else/e/ + * a/b/c/d/ => a/b/some/thing/else/ + * so we want to increment counters for both. We do NOT, + * however, also want to suggest that there was the following + * rename: + * a/b/c/ => a/b/some/thing/ + * so we need to quit at that point. + * + * Note the when first_time_in_loop, we only strip off the + * basename, and we don't care if that's different. + */ + if (!first_time_in_loop) { + char *old_sub_dir = strchr(old_dir, '\0')+1; + char *new_sub_dir = strchr(new_dir, '\0')+1; + if (!*new_dir) { + /* + * Special case when renaming to root directory, + * i.e. when new_dir == "". In this case, we had + * something like + * a/b/subdir => subdir + * and so dirname_munge() sets things up so that + * old_dir = "a/b\0subdir\0" + * new_dir = "\0ubdir\0" + * We didn't have a '/' to overwrite a '\0' onto + * in new_dir, so we have to compare differently. + */ + if (new_dir_first_char != old_sub_dir[0] || + strcmp(old_sub_dir+1, new_sub_dir)) + break; + } else { + if (strcmp(old_sub_dir, new_sub_dir)) + break; + } + } + + /* + * Above we suggested that we'd keep recording renames for + * all ancestor directories where the trailing directories + * matched, i.e. for + * "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c" + * we'd increment rename counts for each of + * a/b/c/d/e/ => a/b/some/thing/else/e/ + * a/b/c/d/ => a/b/some/thing/else/ + * However, we only need the rename counts for directories + * in dirs_removed whose value is RELEVANT_FOR_SELF. + * However, we add one special case of also recording it for + * first_time_in_loop because find_basename_matches() can + * use that as a hint to find a good pairing. + */ + if (dirs_removed) + drd_flag = strintmap_get(dirs_removed, old_dir); + if (drd_flag == RELEVANT_FOR_SELF || first_time_in_loop) + increment_count(info, old_dir, new_dir); + + first_time_in_loop = 0; + if (drd_flag == NOT_RELEVANT) + break; + /* If we hit toplevel directory ("") for old or new dir, quit */ + if (!*old_dir || !*new_dir) + break; + } + + /* Free resources we don't need anymore */ + free(old_dir); + free(new_dir); +} + +static void initialize_dir_rename_info(struct dir_rename_info *info, + struct strintmap *relevant_sources, + struct strintmap *dirs_removed, + struct strmap *dir_rename_count, + struct strmap *cached_pairs) +{ + struct hashmap_iter iter; + struct strmap_entry *entry; + int i; + + if (!dirs_removed && !relevant_sources) { + info->setup = 0; + return; + } + info->setup = 1; + + info->dir_rename_count = dir_rename_count; + if (!info->dir_rename_count) { + info->dir_rename_count = xmalloc(sizeof(*dir_rename_count)); + strmap_init(info->dir_rename_count); + } + strintmap_init_with_options(&info->idx_map, -1, NULL, 0); + strmap_init_with_options(&info->dir_rename_guess, NULL, 0); + + /* Setup info->relevant_source_dirs */ + info->relevant_source_dirs = NULL; + if (dirs_removed || !relevant_sources) { + info->relevant_source_dirs = dirs_removed; /* might be NULL */ + } else { + info->relevant_source_dirs = xmalloc(sizeof(struct strintmap)); + strintmap_init(info->relevant_source_dirs, 0 /* unused */); + strintmap_for_each_entry(relevant_sources, &iter, entry) { + char *dirname = get_dirname(entry->key); + if (!dirs_removed || + strintmap_contains(dirs_removed, dirname)) + strintmap_set(info->relevant_source_dirs, + dirname, 0 /* value irrelevant */); + free(dirname); + } + } + + /* + * Loop setting up both info->idx_map, and doing setup of + * info->dir_rename_count. + */ + for (i = 0; i < rename_dst_nr; ++i) { + /* + * For non-renamed files, make idx_map contain mapping of + * filename -> index (index within rename_dst, that is) + */ + if (!rename_dst[i].is_rename) { + char *filename = rename_dst[i].p->two->path; + strintmap_set(&info->idx_map, filename, i); + continue; + } + + /* + * For everything else (i.e. renamed files), make + * dir_rename_count contain a map of a map: + * old_directory -> {new_directory -> count} + * In other words, for every pair look at the directories for + * the old filename and the new filename and count how many + * times that pairing occurs. + */ + update_dir_rename_counts(info, dirs_removed, + rename_dst[i].p->one->path, + rename_dst[i].p->two->path); + } + + /* Add cached_pairs to counts */ + strmap_for_each_entry(cached_pairs, &iter, entry) { + const char *old_name = entry->key; + const char *new_name = entry->value; + if (!new_name) + /* known delete; ignore it */ + continue; + + update_dir_rename_counts(info, dirs_removed, old_name, new_name); + } + + /* + * Now we collapse + * dir_rename_count: old_directory -> {new_directory -> count} + * down to + * dir_rename_guess: old_directory -> best_new_directory + * where best_new_directory is the one with the highest count. + */ + strmap_for_each_entry(info->dir_rename_count, &iter, entry) { + /* entry->key is source_dir */ + struct strintmap *counts = entry->value; + char *best_newdir; + + best_newdir = xstrdup(get_highest_rename_path(counts)); + strmap_put(&info->dir_rename_guess, entry->key, + best_newdir); + } +} + +void partial_clear_dir_rename_count(struct strmap *dir_rename_count) +{ + struct hashmap_iter iter; + struct strmap_entry *entry; + + strmap_for_each_entry(dir_rename_count, &iter, entry) { + struct strintmap *counts = entry->value; + strintmap_clear(counts); + } + strmap_partial_clear(dir_rename_count, 1); +} + +static void cleanup_dir_rename_info(struct dir_rename_info *info, + struct strintmap *dirs_removed, + int keep_dir_rename_count) +{ + struct hashmap_iter iter; + struct strmap_entry *entry; + struct string_list to_remove = STRING_LIST_INIT_NODUP; + int i; + + if (!info->setup) + return; + + /* idx_map */ + strintmap_clear(&info->idx_map); + + /* dir_rename_guess */ + strmap_clear(&info->dir_rename_guess, 1); + + /* relevant_source_dirs */ + if (info->relevant_source_dirs && + info->relevant_source_dirs != dirs_removed) { + strintmap_clear(info->relevant_source_dirs); + FREE_AND_NULL(info->relevant_source_dirs); + } + + /* dir_rename_count */ + if (!keep_dir_rename_count) { + partial_clear_dir_rename_count(info->dir_rename_count); + strmap_clear(info->dir_rename_count, 1); + FREE_AND_NULL(info->dir_rename_count); + return; + } + + /* + * Although dir_rename_count was passed in + * diffcore_rename_extended() and we want to keep it around and + * return it to that caller, we first want to remove any counts in + * the maps associated with UNKNOWN_DIR entries and any data + * associated with directories that weren't renamed. + */ + strmap_for_each_entry(info->dir_rename_count, &iter, entry) { + const char *source_dir = entry->key; + struct strintmap *counts = entry->value; + + if (!strintmap_get(dirs_removed, source_dir)) { + string_list_append(&to_remove, source_dir); + strintmap_clear(counts); + continue; + } + + if (strintmap_contains(counts, UNKNOWN_DIR)) + strintmap_remove(counts, UNKNOWN_DIR); + } + for (i = 0; i < to_remove.nr; ++i) + strmap_remove(info->dir_rename_count, + to_remove.items[i].string, 1); + string_list_clear(&to_remove, 0); +} + +static const char *get_basename(const char *filename) +{ + /* + * gitbasename() has to worry about special drives, multiple + * directory separator characters, trailing slashes, NULL or + * empty strings, etc. We only work on filenames as stored in + * git, and thus get to ignore all those complications. + */ + const char *base = strrchr(filename, '/'); + return base ? base + 1 : filename; +} + +static int idx_possible_rename(char *filename, struct dir_rename_info *info) +{ + /* + * Our comparison of files with the same basename (see + * find_basename_matches() below), is only helpful when after exact + * rename detection we have exactly one file with a given basename + * among the rename sources and also only exactly one file with + * that basename among the rename destinations. When we have + * multiple files with the same basename in either set, we do not + * know which to compare against. However, there are some + * filenames that occur in large numbers (particularly + * build-related filenames such as 'Makefile', '.gitignore', or + * 'build.gradle' that potentially exist within every single + * subdirectory), and for performance we want to be able to quickly + * find renames for these files too. + * + * The reason basename comparisons are a useful heuristic was that it + * is common for people to move files across directories while keeping + * their filename the same. If we had a way of determining or even + * making a good educated guess about which directory these non-unique + * basename files had moved the file to, we could check it. + * Luckily... + * + * When an entire directory is in fact renamed, we have two factors + * helping us out: + * (a) the original directory disappeared giving us a hint + * about when we can apply an extra heuristic. + * (a) we often have several files within that directory and + * subdirectories that are renamed without changes + * So, rules for a heuristic: + * (0) If there basename matches are non-unique (the condition under + * which this function is called) AND + * (1) the directory in which the file was found has disappeared + * (i.e. dirs_removed is non-NULL and has a relevant entry) THEN + * (2) use exact renames of files within the directory to determine + * where the directory is likely to have been renamed to. IF + * there is at least one exact rename from within that + * directory, we can proceed. + * (3) If there are multiple places the directory could have been + * renamed to based on exact renames, ignore all but one of them. + * Just use the destination with the most renames going to it. + * (4) Check if applying that directory rename to the original file + * would result in a destination filename that is in the + * potential rename set. If so, return the index of the + * destination file (the index within rename_dst). + * (5) Compare the original file and returned destination for + * similarity, and if they are sufficiently similar, record the + * rename. + * + * This function, idx_possible_rename(), is only responsible for (4). + * The conditions/steps in (1)-(3) are handled via setting up + * dir_rename_count and dir_rename_guess in + * initialize_dir_rename_info(). Steps (0) and (5) are handled by + * the caller of this function. + */ + char *old_dir, *new_dir; + struct strbuf new_path = STRBUF_INIT; + int idx; + + if (!info->setup) + return -1; + + old_dir = get_dirname(filename); + new_dir = strmap_get(&info->dir_rename_guess, old_dir); + free(old_dir); + if (!new_dir) + return -1; + + strbuf_addstr(&new_path, new_dir); + strbuf_addch(&new_path, '/'); + strbuf_addstr(&new_path, get_basename(filename)); + + idx = strintmap_get(&info->idx_map, new_path.buf); + strbuf_release(&new_path); + return idx; +} + +struct basename_prefetch_options { + struct repository *repo; + struct strintmap *relevant_sources; + struct strintmap *sources; + struct strintmap *dests; + struct dir_rename_info *info; +}; +static void basename_prefetch(void *prefetch_options) +{ + struct basename_prefetch_options *options = prefetch_options; + struct strintmap *relevant_sources = options->relevant_sources; + struct strintmap *sources = options->sources; + struct strintmap *dests = options->dests; + struct dir_rename_info *info = options->info; + int i; + struct oid_array to_fetch = OID_ARRAY_INIT; + + /* + * TODO: The following loops mirror the code/logic from + * find_basename_matches(), though not quite exactly. Maybe + * abstract the iteration logic out somehow? + */ + for (i = 0; i < rename_src_nr; ++i) { + char *filename = rename_src[i].p->one->path; + const char *base = NULL; + intptr_t src_index; + intptr_t dst_index; + + /* Skip irrelevant sources */ + if (relevant_sources && + !strintmap_contains(relevant_sources, filename)) + continue; + + /* + * If the basename is unique among remaining sources, then + * src_index will equal 'i' and we can attempt to match it + * to a unique basename in the destinations. Otherwise, + * use directory rename heuristics, if possible. + */ + base = get_basename(filename); + src_index = strintmap_get(sources, base); + assert(src_index == -1 || src_index == i); + + if (strintmap_contains(dests, base)) { + struct diff_filespec *one, *two; + + /* Find a matching destination, if possible */ + dst_index = strintmap_get(dests, base); + if (src_index == -1 || dst_index == -1) { + src_index = i; + dst_index = idx_possible_rename(filename, info); + } + if (dst_index == -1) + continue; + + /* Ignore this dest if already used in a rename */ + if (rename_dst[dst_index].is_rename) + continue; /* already used previously */ + + one = rename_src[src_index].p->one; + two = rename_dst[dst_index].p->two; + + /* Add the pairs */ + diff_add_if_missing(options->repo, &to_fetch, two); + diff_add_if_missing(options->repo, &to_fetch, one); + } + } + + promisor_remote_get_direct(options->repo, to_fetch.oid, to_fetch.nr); + oid_array_clear(&to_fetch); +} + +static int find_basename_matches(struct diff_options *options, + int minimum_score, + struct dir_rename_info *info, + struct strintmap *relevant_sources, + struct strintmap *dirs_removed) +{ + /* + * When I checked in early 2020, over 76% of file renames in linux + * just moved files to a different directory but kept the same + * basename. gcc did that with over 64% of renames, gecko did it + * with over 79%, and WebKit did it with over 89%. + * + * Therefore we can bypass the normal exhaustive NxM matrix + * comparison of similarities between all potential rename sources + * and destinations by instead using file basename as a hint (i.e. + * the portion of the filename after the last '/'), checking for + * similarity between files with the same basename, and if we find + * a pair that are sufficiently similar, record the rename pair and + * exclude those two from the NxM matrix. + * + * This *might* cause us to find a less than optimal pairing (if + * there is another file that we are even more similar to but has a + * different basename). Given the huge performance advantage + * basename matching provides, and given the frequency with which + * people use the same basename in real world projects, that's a + * trade-off we are willing to accept when doing just rename + * detection. + * + * If someone wants copy detection that implies they are willing to + * spend more cycles to find similarities between files, so it may + * be less likely that this heuristic is wanted. If someone is + * doing break detection, that means they do not want filename + * similarity to imply any form of content similiarity, and thus + * this heuristic would definitely be incompatible. + */ + + int i, renames = 0; + struct strintmap sources; + struct strintmap dests; + struct diff_populate_filespec_options dpf_options = { + .check_binary = 0, + .missing_object_cb = NULL, + .missing_object_data = NULL + }; + struct basename_prefetch_options prefetch_options = { + .repo = options->repo, + .relevant_sources = relevant_sources, + .sources = &sources, + .dests = &dests, + .info = info + }; + + /* + * Create maps of basename -> fullname(s) for remaining sources and + * dests. + */ + strintmap_init_with_options(&sources, -1, NULL, 0); + strintmap_init_with_options(&dests, -1, NULL, 0); + for (i = 0; i < rename_src_nr; ++i) { + char *filename = rename_src[i].p->one->path; + const char *base; + + /* exact renames removed in remove_unneeded_paths_from_src() */ + assert(!rename_src[i].p->one->rename_used); + + /* Record index within rename_src (i) if basename is unique */ + base = get_basename(filename); + if (strintmap_contains(&sources, base)) + strintmap_set(&sources, base, -1); + else + strintmap_set(&sources, base, i); + } + for (i = 0; i < rename_dst_nr; ++i) { + char *filename = rename_dst[i].p->two->path; + const char *base; + + if (rename_dst[i].is_rename) + continue; /* involved in exact match already. */ + + /* Record index within rename_dst (i) if basename is unique */ + base = get_basename(filename); + if (strintmap_contains(&dests, base)) + strintmap_set(&dests, base, -1); + else + strintmap_set(&dests, base, i); + } + + if (options->repo == the_repository && repo_has_promisor_remote(the_repository)) { + dpf_options.missing_object_cb = basename_prefetch; + dpf_options.missing_object_data = &prefetch_options; + } + + /* Now look for basename matchups and do similarity estimation */ + for (i = 0; i < rename_src_nr; ++i) { + char *filename = rename_src[i].p->one->path; + const char *base = NULL; + intptr_t src_index; + intptr_t dst_index; + + /* Skip irrelevant sources */ + if (relevant_sources && + !strintmap_contains(relevant_sources, filename)) + continue; + + /* + * If the basename is unique among remaining sources, then + * src_index will equal 'i' and we can attempt to match it + * to a unique basename in the destinations. Otherwise, + * use directory rename heuristics, if possible. + */ + base = get_basename(filename); + src_index = strintmap_get(&sources, base); + assert(src_index == -1 || src_index == i); + + if (strintmap_contains(&dests, base)) { + struct diff_filespec *one, *two; + int score; + + /* Find a matching destination, if possible */ + dst_index = strintmap_get(&dests, base); + if (src_index == -1 || dst_index == -1) { + src_index = i; + dst_index = idx_possible_rename(filename, info); + } + if (dst_index == -1) + continue; + + /* Ignore this dest if already used in a rename */ + if (rename_dst[dst_index].is_rename) + continue; /* already used previously */ + + /* Estimate the similarity */ + one = rename_src[src_index].p->one; + two = rename_dst[dst_index].p->two; + score = estimate_similarity(options->repo, one, two, + minimum_score, &dpf_options); + + /* If sufficiently similar, record as rename pair */ + if (score < minimum_score) + continue; + record_rename_pair(dst_index, src_index, score); + renames++; + update_dir_rename_counts(info, dirs_removed, + one->path, two->path); + + /* + * Found a rename so don't need text anymore; if we + * didn't find a rename, the filespec_blob would get + * re-used when doing the matrix of comparisons. + */ + diff_free_filespec_blob(one); + diff_free_filespec_blob(two); + } + } + + strintmap_clear(&sources); + strintmap_clear(&dests); + + 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_destinations, int num_sources, + struct diff_options *options) +{ + int rename_limit = options->rename_limit; + int i, limited_sources; + + 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_destinations * num_sources > rename_limit * rename_limit + * + * We use st_mult() to check overflow conditions; in the + * exceptional circumstance that size_t isn't large enough to hold + * the multiplication, the system won't be able to allocate enough + * memory for the matrix anyway. + */ + if (rename_limit <= 0) + return 0; /* treat as unlimited */ + if (st_mult(num_destinations, num_sources) + <= st_mult(rename_limit, rename_limit)) + return 0; + + options->needed_rename_limit = + num_sources > num_destinations ? num_sources : num_destinations; + + /* 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 (limited_sources = i = 0; i < num_sources; i++) { + if (diff_unmodified_pair(rename_src[i].p)) + continue; + limited_sources++; + } + if (st_mult(num_destinations, limited_sources) + <= st_mult(rename_limit, rename_limit)) + return 2; + return 1; +} + +static int find_renames(struct diff_score *mx, + int dst_cnt, + int minimum_score, + int copies, + struct dir_rename_info *info, + struct strintmap *dirs_removed) +{ + 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->is_rename) + 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++; + update_dir_rename_counts(info, dirs_removed, + rename_src[mx[i].src].p->one->path, + rename_dst[mx[i].dst].p->two->path); + } + return count; +} + +static void remove_unneeded_paths_from_src(int detecting_copies, + struct strintmap *interesting) +{ + int i, new_num_src; + + if (detecting_copies && !interesting) + return; /* nothing to remove */ + if (break_idx) + return; /* culling incompatible with break detection */ + + /* + * Note on reasons why we cull unneeded sources but not destinations: + * 1) Pairings are stored in rename_dst (not rename_src), which we + * need to keep around. So, we just can't cull rename_dst even + * if we wanted to. But doing so wouldn't help because... + * + * 2) There is a matrix pairwise comparison that follows the + * "Performing inexact rename detection" progress message. + * Iterating over the destinations is done in the outer loop, + * hence we only iterate over each of those once and we can + * easily skip the outer loop early if the destination isn't + * relevant. That's only one check per destination path to + * skip. + * + * By contrast, the sources are iterated in the inner loop; if + * we check whether a source can be skipped, then we'll be + * checking it N separate times, once for each destination. + * We don't want to have to iterate over known-not-needed + * sources N times each, so avoid that by removing the sources + * from rename_src here. + */ + for (i = 0, new_num_src = 0; i < rename_src_nr; i++) { + struct diff_filespec *one = rename_src[i].p->one; + + /* + * renames are stored in rename_dst, so if a rename has + * already been detected using this source, we can just + * remove the source knowing rename_dst has its info. + */ + if (!detecting_copies && one->rename_used) + continue; + + /* If we don't care about the source path, skip it */ + if (interesting && !strintmap_contains(interesting, one->path)) + continue; + + if (new_num_src < i) + memcpy(&rename_src[new_num_src], &rename_src[i], + sizeof(struct diff_rename_src)); + new_num_src++; + } + + rename_src_nr = new_num_src; +} + +static void handle_early_known_dir_renames(struct dir_rename_info *info, + struct strintmap *relevant_sources, + struct strintmap *dirs_removed) +{ + /* + * Directory renames are determined via an aggregate of all renames + * under them and using a "majority wins" rule. The fact that + * "majority wins", though, means we don't need all the renames + * under the given directory, we only need enough to ensure we have + * a majority. + */ + + int i, new_num_src; + struct hashmap_iter iter; + struct strmap_entry *entry; + + if (!dirs_removed || !relevant_sources) + return; /* nothing to cull */ + if (break_idx) + return; /* culling incompatbile with break detection */ + + /* + * Supplement dir_rename_count with number of potential renames, + * marking all potential rename sources as mapping to UNKNOWN_DIR. + */ + for (i = 0; i < rename_src_nr; i++) { + char *old_dir; + struct diff_filespec *one = rename_src[i].p->one; + + /* + * sources that are part of a rename will have already been + * removed by a prior call to remove_unneeded_paths_from_src() + */ + assert(!one->rename_used); + + old_dir = get_dirname(one->path); + while (*old_dir != '\0' && + NOT_RELEVANT != strintmap_get(dirs_removed, old_dir)) { + char *freeme = old_dir; + + increment_count(info, old_dir, UNKNOWN_DIR); + old_dir = get_dirname(old_dir); + + /* Free resources we don't need anymore */ + free(freeme); + } + /* + * old_dir and new_dir free'd in increment_count, but + * get_dirname() gives us a new pointer we need to free for + * old_dir. Also, if the loop runs 0 times we need old_dir + * to be freed. + */ + free(old_dir); + } + + /* + * For any directory which we need a potential rename detected for + * (i.e. those marked as RELEVANT_FOR_SELF in dirs_removed), check + * whether we have enough renames to satisfy the "majority rules" + * requirement such that detecting any more renames of files under + * it won't change the result. For any such directory, mark that + * we no longer need to detect a rename for it. However, since we + * might need to still detect renames for an ancestor of that + * directory, use RELEVANT_FOR_ANCESTOR. + */ + strmap_for_each_entry(info->dir_rename_count, &iter, entry) { + /* entry->key is source_dir */ + struct strintmap *counts = entry->value; + + if (strintmap_get(dirs_removed, entry->key) == + RELEVANT_FOR_SELF && + dir_rename_already_determinable(counts)) { + strintmap_set(dirs_removed, entry->key, + RELEVANT_FOR_ANCESTOR); + } + } + + for (i = 0, new_num_src = 0; i < rename_src_nr; i++) { + struct diff_filespec *one = rename_src[i].p->one; + int val; + + val = strintmap_get(relevant_sources, one->path); + + /* + * sources that were not found in relevant_sources should + * have already been removed by a prior call to + * remove_unneeded_paths_from_src() + */ + assert(val != -1); + + if (val == RELEVANT_LOCATION) { + int removable = 1; + char *dir = get_dirname(one->path); + while (1) { + char *freeme = dir; + int res = strintmap_get(dirs_removed, dir); + + /* Quit if not found or irrelevant */ + if (res == NOT_RELEVANT) + break; + /* If RELEVANT_FOR_SELF, can't remove */ + if (res == RELEVANT_FOR_SELF) { + removable = 0; + break; + } + /* Else continue searching upwards */ + assert(res == RELEVANT_FOR_ANCESTOR); + dir = get_dirname(dir); + free(freeme); + } + free(dir); + if (removable) { + strintmap_set(relevant_sources, one->path, + RELEVANT_NO_MORE); + continue; + } + } + + if (new_num_src < i) + memcpy(&rename_src[new_num_src], &rename_src[i], + sizeof(struct diff_rename_src)); + new_num_src++; + } + + rename_src_nr = new_num_src; +} + +static void free_filespec_data(struct diff_filespec *spec) +{ + if (!--spec->count) + diff_free_filespec_data(spec); +} + +static void pool_free_filespec(struct mem_pool *pool, + struct diff_filespec *spec) +{ + if (!pool) { + free_filespec(spec); + return; + } + + /* + * Similar to free_filespec(), but only frees the data. The spec + * itself was allocated in the pool and should not be individually + * freed. + */ + free_filespec_data(spec); +} + +void pool_diff_free_filepair(struct mem_pool *pool, + struct diff_filepair *p) +{ + if (!pool) { + diff_free_filepair(p); + return; + } + + /* + * Similar to diff_free_filepair() but only frees the data from the + * filespecs; not the filespecs or the filepair which were + * allocated from the pool. + */ + free_filespec_data(p->one); + free_filespec_data(p->two); +} + +void diffcore_rename_extended(struct diff_options *options, + struct mem_pool *pool, + struct strintmap *relevant_sources, + struct strintmap *dirs_removed, + struct strmap *dir_rename_count, + struct strmap *cached_pairs) +{ + 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_destinations, dst_cnt; + int num_sources, want_copies; + struct progress *progress = NULL; + struct mem_pool local_pool; + struct dir_rename_info info; + struct diff_populate_filespec_options dpf_options = { + .check_binary = 0, + .missing_object_cb = NULL, + .missing_object_data = NULL + }; + struct inexact_prefetch_options prefetch_options = { + .repo = options->repo + }; + + trace2_region_enter("diff", "setup", options->repo); + info.setup = 0; + assert(!dir_rename_count || strmap_empty(dir_rename_count)); + want_copies = (detect_rename == DIFF_DETECT_COPY); + if (dirs_removed && (break_idx || want_copies)) + BUG("dirs_removed incompatible with break/copy detection"); + if (break_idx && relevant_sources) + BUG("break detection incompatible with source specification"); + 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) < 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 (want_copies) { + /* + * Increment the "rename_used" score by + * one, to indicate ourselves as a user. + */ + p->one->rename_used++; + register_rename_src(p); + } + } + trace2_region_leave("diff", "setup", options->repo); + if (rename_dst_nr == 0 || rename_src_nr == 0) + goto cleanup; /* nothing to do */ + + trace2_region_enter("diff", "exact renames", options->repo); + mem_pool_init(&local_pool, 32*1024); + /* + * We really want to cull the candidates list early + * with cheap tests in order to avoid doing deltas. + */ + rename_count = find_exact_renames(options, &local_pool); + /* + * Discard local_pool immediately instead of at "cleanup:" in order + * to reduce maximum memory usage; inexact rename detection uses up + * a fair amount of memory, and mem_pools can too. + */ + mem_pool_discard(&local_pool, 0); + trace2_region_leave("diff", "exact renames", options->repo); + + /* Did we only want exact renames? */ + if (minimum_score == MAX_SCORE) + goto cleanup; + + num_sources = rename_src_nr; + + if (want_copies || break_idx) { + /* + * Cull sources: + * - remove ones corresponding to exact renames + * - remove ones not found in relevant_sources + */ + trace2_region_enter("diff", "cull after exact", options->repo); + remove_unneeded_paths_from_src(want_copies, relevant_sources); + trace2_region_leave("diff", "cull after exact", options->repo); + } else { + /* Determine minimum score to match basenames */ + double factor = 0.5; + char *basename_factor = getenv("GIT_BASENAME_FACTOR"); + int min_basename_score; + + if (basename_factor) + factor = strtol(basename_factor, NULL, 10)/100.0; + assert(factor >= 0.0 && factor <= 1.0); + min_basename_score = minimum_score + + (int)(factor * (MAX_SCORE - minimum_score)); + + /* + * Cull sources: + * - remove ones involved in renames (found via exact match) + */ + trace2_region_enter("diff", "cull after exact", options->repo); + remove_unneeded_paths_from_src(want_copies, NULL); + trace2_region_leave("diff", "cull after exact", options->repo); + + /* Preparation for basename-driven matching. */ + trace2_region_enter("diff", "dir rename setup", options->repo); + initialize_dir_rename_info(&info, relevant_sources, + dirs_removed, dir_rename_count, + cached_pairs); + trace2_region_leave("diff", "dir rename setup", options->repo); + + /* Utilize file basenames to quickly find renames. */ + trace2_region_enter("diff", "basename matches", options->repo); + rename_count += find_basename_matches(options, + min_basename_score, + &info, + relevant_sources, + dirs_removed); + trace2_region_leave("diff", "basename matches", options->repo); + + /* + * Cull sources, again: + * - remove ones involved in renames (found via basenames) + * - remove ones not found in relevant_sources + * and + * - remove ones in relevant_sources which are needed only + * for directory renames IF no ancestory directory + * actually needs to know any more individual path + * renames under them + */ + trace2_region_enter("diff", "cull basename", options->repo); + remove_unneeded_paths_from_src(want_copies, relevant_sources); + handle_early_known_dir_renames(&info, relevant_sources, + dirs_removed); + trace2_region_leave("diff", "cull basename", options->repo); + } + + /* Calculate how many rename destinations are left */ + num_destinations = (rename_dst_nr - rename_count); + num_sources = rename_src_nr; /* rename_src_nr reflects lower number */ + + /* All done? */ + if (!num_destinations || !num_sources) + goto cleanup; + + switch (too_many_rename_candidates(num_destinations, num_sources, + options)) { + case 1: + goto cleanup; + case 2: + options->degraded_cc_to_c = 1; + skip_unmodified = 1; + break; + default: + break; + } + + trace2_region_enter("diff", "inexact renames", options->repo); + if (options->show_rename_progress) { + progress = start_delayed_progress( + _("Performing inexact rename detection"), + (uint64_t)num_destinations * (uint64_t)num_sources); + } + + /* Finish setting up dpf_options */ + prefetch_options.skip_unmodified = skip_unmodified; + if (options->repo == the_repository && repo_has_promisor_remote(the_repository)) { + dpf_options.missing_object_cb = inexact_prefetch; + dpf_options.missing_object_data = &prefetch_options; + } + + CALLOC_ARRAY(mx, st_mult(NUM_CANDIDATE_PER_DST, num_destinations)); + for (dst_cnt = i = 0; i < rename_dst_nr; i++) { + struct diff_filespec *two = rename_dst[i].p->two; + struct diff_score *m; + + if (rename_dst[i].is_rename) + continue; /* exact or basename match already handled */ + + 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; + + assert(!one->rename_used || want_copies || break_idx); + + if (skip_unmodified && + diff_unmodified_pair(rename_src[j].p)) + continue; + + this_src.score = estimate_similarity(options->repo, + one, two, + minimum_score, + &dpf_options); + 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)dst_cnt * (uint64_t)num_sources); + } + stop_progress(&progress); + + /* cost matrix sorted by most to least similar pair */ + STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); + + rename_count += find_renames(mx, dst_cnt, minimum_score, 0, + &info, dirs_removed); + if (want_copies) + rename_count += find_renames(mx, dst_cnt, minimum_score, 1, + &info, dirs_removed); + free(mx); + trace2_region_leave("diff", "inexact renames", options->repo); + + 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. + */ + trace2_region_enter("diff", "write back to queue", options->repo); + 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 */ + 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); + if (!dst) + BUG("tracking failed somehow; failed to find associated dst for broken pair"); + if (dst->is_rename) + /* 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) + 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) + pool_diff_free_filepair(pool, 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++) + if (rename_dst[i].filespec_to_free) + pool_free_filespec(pool, rename_dst[i].filespec_to_free); + + cleanup_dir_rename_info(&info, dirs_removed, dir_rename_count != NULL); + FREE_AND_NULL(rename_dst); + rename_dst_nr = rename_dst_alloc = 0; + FREE_AND_NULL(rename_src); + rename_src_nr = rename_src_alloc = 0; + if (break_idx) { + strintmap_clear(break_idx); + FREE_AND_NULL(break_idx); + } + trace2_region_leave("diff", "write back to queue", options->repo); + return; +} + +void diffcore_rename(struct diff_options *options) +{ + diffcore_rename_extended(options, NULL, NULL, NULL, NULL, NULL); +} |