git/diffcore-rename.c
Elijah Newren bd24aa2f97 diffcore-rename: guide inexact rename detection based on basenames
Make use of the new find_basename_matches() function added in the last
two patches, to find renames more rapidly in cases where we can match up
files based on basenames.  As a quick reminder (see the last two commit
messages for more details), this means for example that
docs/extensions.txt and docs/config/extensions.txt are considered likely
renames if there are no remaining 'extensions.txt' files elsewhere among
the added and deleted files, and if a similarity check confirms they are
similar, then they are marked as a rename without looking for a better
similarity match among other files.  This is a behavioral change, as
covered in more detail in the previous commit message.

We do not use this heuristic together with either break or copy
detection.  The point of break detection is to say that filename
similarity does not imply file content similarity, and we only want to
know about file content similarity.  The point of copy detection is to
use more resources to check for additional similarities, while this is
an optimization that uses far less resources but which might also result
in finding slightly fewer similarities.  So the idea behind this
optimization goes against both of those features, and will be turned off
for both.

For the testcases mentioned in commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2020-10-28),
this change improves the performance as follows:

                            Before                  After
    no-renames:       13.815 s ±  0.062 s    13.294 s ±  0.103 s
    mega-renames:   1799.937 s ±  0.493 s   187.248 s ±  0.882 s
    just-one-mega:    51.289 s ±  0.019 s     5.557 s ±  0.017 s

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-15 18:02:16 -08:00

926 lines
27 KiB
C

/*
*
* 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"
#include "promisor-remote.h"
#include "strmap.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(break_idx, -1);
}
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 prefetch_options {
struct repository *repo;
int skip_unmodified;
};
static void prefetch(void *prefetch_options)
{
struct 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,
int skip_unmodified)
{
/* 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;
struct diff_populate_filespec_options dpf_options = {
.check_size_only = 1
};
struct prefetch_options prefetch_options = {r, skip_unmodified};
if (r == the_repository && has_promisor_remote()) {
dpf_options.missing_object_cb = prefetch;
dpf_options.missing_object_data = &prefetch_options;
}
/* 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, &dpf_options))
return 0;
if (!dst->cnt_data &&
diff_populate_filespec(r, dst, &dpf_options))
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_options.check_size_only = 0;
if (!src->cnt_data && diff_populate_filespec(r, src, &dpf_options))
return 0;
if (!dst->cnt_data && diff_populate_filespec(r, dst, &dpf_options))
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,
"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 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->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)
{
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_clear_and_free(&file_table, struct file_similarity, entry);
return renames;
}
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 find_basename_matches(struct diff_options *options,
int minimum_score)
{
/*
* 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 hashmap_iter iter;
struct strmap_entry *entry;
/*
* The prefeteching stuff wants to know if it can skip prefetching
* blobs that are unmodified...and will then do a little extra work
* to verify that the oids are indeed different before prefetching.
* Unmodified blobs are only relevant when doing copy detection;
* when limiting to rename detection, diffcore_rename[_extended]()
* will never be called with unmodified source paths fed to us, so
* the extra work necessary to check if rename_src entries are
* unmodified would be a small waste.
*/
int skip_unmodified = 0;
/*
* 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);
}
/* Now look for basename matchups and do similarity estimation */
strintmap_for_each_entry(&sources, &iter, entry) {
const char *base = entry->key;
intptr_t src_index = (intptr_t)entry->value;
intptr_t dst_index;
if (src_index == -1)
continue;
if (0 <= (dst_index = strintmap_get(&dests, base))) {
struct diff_filespec *one, *two;
int score;
/* 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, skip_unmodified);
/* If sufficiently similar, record as rename pair */
if (score < minimum_score)
continue;
record_rename_pair(dst_index, src_index, score);
renames++;
/*
* 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)
rename_limit = 32767;
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)
{
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++;
}
return count;
}
static void remove_unneeded_paths_from_src(int detecting_copies)
{
int i, new_num_src;
if (detecting_copies)
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++) {
/*
* 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 (rename_src[i].p->one->rename_used)
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;
}
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_destinations, dst_cnt;
int num_sources, want_copies;
struct progress *progress = NULL;
trace2_region_enter("diff", "setup", options->repo);
want_copies = (detect_rename == DIFF_DETECT_COPY);
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);
/*
* We really want to cull the candidates list early
* with cheap tests in order to avoid doing deltas.
*/
rename_count = find_exact_renames(options);
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
*/
trace2_region_enter("diff", "cull after exact", options->repo);
remove_unneeded_paths_from_src(want_copies);
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);
trace2_region_leave("diff", "cull after exact", 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);
trace2_region_leave("diff", "basename matches", options->repo);
/*
* Cull sources, again:
* - remove ones involved in renames (found via basenames)
*/
trace2_region_enter("diff", "cull basename", options->repo);
remove_unneeded_paths_from_src(want_copies);
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);
}
mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_destinations),
sizeof(*mx));
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,
skip_unmodified);
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);
if (want_copies)
rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
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; FIXME: remove earlier? */
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++)
if (rename_dst[i].filespec_to_free)
free_filespec(rename_dst[i].filespec_to_free);
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;
}