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diff_tform.c
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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include "diff_tform.h"
#include "git2/config.h"
#include "git2/blob.h"
#include "git2/sys/hashsig.h"
#include "diff.h"
#include "diff_generate.h"
#include "path.h"
#include "futils.h"
#include "config.h"
git_diff_delta *git_diff__delta_dup(
const git_diff_delta *d, git_pool *pool)
{
git_diff_delta *delta = git__malloc(sizeof(git_diff_delta));
if (!delta)
return NULL;
memcpy(delta, d, sizeof(git_diff_delta));
GIT_DIFF_FLAG__CLEAR_INTERNAL(delta->flags);
if (d->old_file.path != NULL) {
delta->old_file.path = git_pool_strdup(pool, d->old_file.path);
if (delta->old_file.path == NULL)
goto fail;
}
if (d->new_file.path != d->old_file.path && d->new_file.path != NULL) {
delta->new_file.path = git_pool_strdup(pool, d->new_file.path);
if (delta->new_file.path == NULL)
goto fail;
} else {
delta->new_file.path = delta->old_file.path;
}
return delta;
fail:
git__free(delta);
return NULL;
}
git_diff_delta *git_diff__merge_like_cgit(
const git_diff_delta *a,
const git_diff_delta *b,
git_pool *pool)
{
git_diff_delta *dup;
/* Emulate C git for merging two diffs (a la 'git diff <sha>').
*
* When C git does a diff between the work dir and a tree, it actually
* diffs with the index but uses the workdir contents. This emulates
* those choices so we can emulate the type of diff.
*
* We have three file descriptions here, let's call them:
* f1 = a->old_file
* f2 = a->new_file AND b->old_file
* f3 = b->new_file
*/
/* If one of the diffs is a conflict, just dup it */
if (b->status == GIT_DELTA_CONFLICTED)
return git_diff__delta_dup(b, pool);
if (a->status == GIT_DELTA_CONFLICTED)
return git_diff__delta_dup(a, pool);
/* if f2 == f3 or f2 is deleted, then just dup the 'a' diff */
if (b->status == GIT_DELTA_UNMODIFIED || a->status == GIT_DELTA_DELETED)
return git_diff__delta_dup(a, pool);
/* otherwise, base this diff on the 'b' diff */
if ((dup = git_diff__delta_dup(b, pool)) == NULL)
return NULL;
/* If 'a' status is uninteresting, then we're done */
if (a->status == GIT_DELTA_UNMODIFIED ||
a->status == GIT_DELTA_UNTRACKED ||
a->status == GIT_DELTA_UNREADABLE)
return dup;
GIT_ASSERT_WITH_RETVAL(b->status != GIT_DELTA_UNMODIFIED, NULL);
/* A cgit exception is that the diff of a file that is only in the
* index (i.e. not in HEAD nor workdir) is given as empty.
*/
if (dup->status == GIT_DELTA_DELETED) {
if (a->status == GIT_DELTA_ADDED) {
dup->status = GIT_DELTA_UNMODIFIED;
dup->nfiles = 2;
}
/* else don't overwrite DELETE status */
} else {
dup->status = a->status;
dup->nfiles = a->nfiles;
}
git_oid_cpy(&dup->old_file.id, &a->old_file.id);
dup->old_file.mode = a->old_file.mode;
dup->old_file.size = a->old_file.size;
dup->old_file.flags = a->old_file.flags;
return dup;
}
int git_diff__merge(
git_diff *onto, const git_diff *from, git_diff__merge_cb cb)
{
int error = 0;
git_pool onto_pool;
git_vector onto_new;
git_diff_delta *delta;
bool ignore_case, reversed;
unsigned int i, j;
GIT_ASSERT_ARG(onto);
GIT_ASSERT_ARG(from);
if (!from->deltas.length)
return 0;
ignore_case = ((onto->opts.flags & GIT_DIFF_IGNORE_CASE) != 0);
reversed = ((onto->opts.flags & GIT_DIFF_REVERSE) != 0);
if (ignore_case != ((from->opts.flags & GIT_DIFF_IGNORE_CASE) != 0) ||
reversed != ((from->opts.flags & GIT_DIFF_REVERSE) != 0)) {
git_error_set(GIT_ERROR_INVALID,
"attempt to merge diffs created with conflicting options");
return -1;
}
if (git_vector_init(&onto_new, onto->deltas.length, git_diff_delta__cmp) < 0 ||
git_pool_init(&onto_pool, 1) < 0)
return -1;
for (i = 0, j = 0; i < onto->deltas.length || j < from->deltas.length; ) {
git_diff_delta *o = GIT_VECTOR_GET(&onto->deltas, i);
const git_diff_delta *f = GIT_VECTOR_GET(&from->deltas, j);
int cmp = !f ? -1 : !o ? 1 :
STRCMP_CASESELECT(ignore_case, o->old_file.path, f->old_file.path);
if (cmp < 0) {
delta = git_diff__delta_dup(o, &onto_pool);
i++;
} else if (cmp > 0) {
delta = git_diff__delta_dup(f, &onto_pool);
j++;
} else {
const git_diff_delta *left = reversed ? f : o;
const git_diff_delta *right = reversed ? o : f;
delta = cb(left, right, &onto_pool);
i++;
j++;
}
/* the ignore rules for the target may not match the source
* or the result of a merged delta could be skippable...
*/
if (delta && git_diff_delta__should_skip(&onto->opts, delta)) {
git__free(delta);
continue;
}
if ((error = !delta ? -1 : git_vector_insert(&onto_new, delta)) < 0)
break;
}
if (!error) {
git_vector_swap(&onto->deltas, &onto_new);
git_pool_swap(&onto->pool, &onto_pool);
if ((onto->opts.flags & GIT_DIFF_REVERSE) != 0)
onto->old_src = from->old_src;
else
onto->new_src = from->new_src;
/* prefix strings also come from old pool, so recreate those.*/
onto->opts.old_prefix =
git_pool_strdup_safe(&onto->pool, onto->opts.old_prefix);
onto->opts.new_prefix =
git_pool_strdup_safe(&onto->pool, onto->opts.new_prefix);
}
git_vector_free_deep(&onto_new);
git_pool_clear(&onto_pool);
return error;
}
int git_diff_merge(git_diff *onto, const git_diff *from)
{
return git_diff__merge(onto, from, git_diff__merge_like_cgit);
}
int git_diff_find_similar__hashsig_for_file(
void **out, const git_diff_file *f, const char *path, void *p)
{
git_hashsig_option_t opt = (git_hashsig_option_t)(intptr_t)p;
GIT_UNUSED(f);
return git_hashsig_create_fromfile((git_hashsig **)out, path, opt);
}
int git_diff_find_similar__hashsig_for_buf(
void **out, const git_diff_file *f, const char *buf, size_t len, void *p)
{
git_hashsig_option_t opt = (git_hashsig_option_t)(intptr_t)p;
GIT_UNUSED(f);
return git_hashsig_create((git_hashsig **)out, buf, len, opt);
}
void git_diff_find_similar__hashsig_free(void *sig, void *payload)
{
GIT_UNUSED(payload);
git_hashsig_free(sig);
}
int git_diff_find_similar__calc_similarity(
int *score, void *siga, void *sigb, void *payload)
{
int error;
GIT_UNUSED(payload);
error = git_hashsig_compare(siga, sigb);
if (error < 0)
return error;
*score = error;
return 0;
}
#define DEFAULT_THRESHOLD 50
#define DEFAULT_BREAK_REWRITE_THRESHOLD 60
#define DEFAULT_RENAME_LIMIT 200
static int normalize_find_opts(
git_diff *diff,
git_diff_find_options *opts,
const git_diff_find_options *given)
{
git_config *cfg = NULL;
git_hashsig_option_t hashsig_opts;
GIT_ERROR_CHECK_VERSION(given, GIT_DIFF_FIND_OPTIONS_VERSION, "git_diff_find_options");
if (diff->repo != NULL &&
git_repository_config__weakptr(&cfg, diff->repo) < 0)
return -1;
if (given)
memcpy(opts, given, sizeof(*opts));
if (!given ||
(given->flags & GIT_DIFF_FIND_ALL) == GIT_DIFF_FIND_BY_CONFIG)
{
if (cfg) {
char *rule =
git_config__get_string_force(cfg, "diff.renames", "true");
int boolval;
if (!git__parse_bool(&boolval, rule) && !boolval)
/* don't set FIND_RENAMES if bool value is false */;
else if (!strcasecmp(rule, "copies") || !strcasecmp(rule, "copy"))
opts->flags |= GIT_DIFF_FIND_RENAMES | GIT_DIFF_FIND_COPIES;
else
opts->flags |= GIT_DIFF_FIND_RENAMES;
git__free(rule);
} else {
/* set default flag */
opts->flags |= GIT_DIFF_FIND_RENAMES;
}
}
/* some flags imply others */
if (opts->flags & GIT_DIFF_FIND_EXACT_MATCH_ONLY) {
/* if we are only looking for exact matches, then don't turn
* MODIFIED items into ADD/DELETE pairs because it's too picky
*/
opts->flags &= ~(GIT_DIFF_FIND_REWRITES | GIT_DIFF_BREAK_REWRITES);
/* similarly, don't look for self-rewrites to split */
opts->flags &= ~GIT_DIFF_FIND_RENAMES_FROM_REWRITES;
}
if (opts->flags & GIT_DIFF_FIND_RENAMES_FROM_REWRITES)
opts->flags |= GIT_DIFF_FIND_RENAMES;
if (opts->flags & GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED)
opts->flags |= GIT_DIFF_FIND_COPIES;
if (opts->flags & GIT_DIFF_BREAK_REWRITES)
opts->flags |= GIT_DIFF_FIND_REWRITES;
#define USE_DEFAULT(X) ((X) == 0 || (X) > 100)
if (USE_DEFAULT(opts->rename_threshold))
opts->rename_threshold = DEFAULT_THRESHOLD;
if (USE_DEFAULT(opts->rename_from_rewrite_threshold))
opts->rename_from_rewrite_threshold = DEFAULT_THRESHOLD;
if (USE_DEFAULT(opts->copy_threshold))
opts->copy_threshold = DEFAULT_THRESHOLD;
if (USE_DEFAULT(opts->break_rewrite_threshold))
opts->break_rewrite_threshold = DEFAULT_BREAK_REWRITE_THRESHOLD;
#undef USE_DEFAULT
if (!opts->rename_limit) {
if (cfg) {
opts->rename_limit = git_config__get_int_force(
cfg, "diff.renamelimit", DEFAULT_RENAME_LIMIT);
}
if (opts->rename_limit <= 0)
opts->rename_limit = DEFAULT_RENAME_LIMIT;
}
/* assign the internal metric with whitespace flag as payload */
if (!opts->metric) {
opts->metric = git__malloc(sizeof(git_diff_similarity_metric));
GIT_ERROR_CHECK_ALLOC(opts->metric);
opts->metric->file_signature = git_diff_find_similar__hashsig_for_file;
opts->metric->buffer_signature = git_diff_find_similar__hashsig_for_buf;
opts->metric->free_signature = git_diff_find_similar__hashsig_free;
opts->metric->similarity = git_diff_find_similar__calc_similarity;
if (opts->flags & GIT_DIFF_FIND_IGNORE_WHITESPACE)
hashsig_opts = GIT_HASHSIG_IGNORE_WHITESPACE;
else if (opts->flags & GIT_DIFF_FIND_DONT_IGNORE_WHITESPACE)
hashsig_opts = GIT_HASHSIG_NORMAL;
else
hashsig_opts = GIT_HASHSIG_SMART_WHITESPACE;
hashsig_opts |= GIT_HASHSIG_ALLOW_SMALL_FILES;
opts->metric->payload = (void *)hashsig_opts;
}
return 0;
}
static int insert_delete_side_of_split(
git_diff *diff, git_vector *onto, const git_diff_delta *delta)
{
/* make new record for DELETED side of split */
git_diff_delta *deleted = git_diff__delta_dup(delta, &diff->pool);
GIT_ERROR_CHECK_ALLOC(deleted);
deleted->status = GIT_DELTA_DELETED;
deleted->nfiles = 1;
memset(&deleted->new_file, 0, sizeof(deleted->new_file));
deleted->new_file.path = deleted->old_file.path;
deleted->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
return git_vector_insert(onto, deleted);
}
static int apply_splits_and_deletes(
git_diff *diff, size_t expected_size, bool actually_split)
{
git_vector onto = GIT_VECTOR_INIT;
size_t i;
git_diff_delta *delta;
if (git_vector_init(&onto, expected_size, git_diff_delta__cmp) < 0)
return -1;
/* build new delta list without TO_DELETE and splitting TO_SPLIT */
git_vector_foreach(&diff->deltas, i, delta) {
if ((delta->flags & GIT_DIFF_FLAG__TO_DELETE) != 0)
continue;
if ((delta->flags & GIT_DIFF_FLAG__TO_SPLIT) != 0 && actually_split) {
delta->similarity = 0;
if (insert_delete_side_of_split(diff, &onto, delta) < 0)
goto on_error;
if (diff->new_src == GIT_ITERATOR_WORKDIR)
delta->status = GIT_DELTA_UNTRACKED;
else
delta->status = GIT_DELTA_ADDED;
delta->nfiles = 1;
memset(&delta->old_file, 0, sizeof(delta->old_file));
delta->old_file.path = delta->new_file.path;
delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
}
/* clean up delta before inserting into new list */
GIT_DIFF_FLAG__CLEAR_INTERNAL(delta->flags);
if (delta->status != GIT_DELTA_COPIED &&
delta->status != GIT_DELTA_RENAMED &&
(delta->status != GIT_DELTA_MODIFIED || actually_split))
delta->similarity = 0;
/* insert into new list */
if (git_vector_insert(&onto, delta) < 0)
goto on_error;
}
/* cannot return an error past this point */
/* free deltas from old list that didn't make it to the new one */
git_vector_foreach(&diff->deltas, i, delta) {
if ((delta->flags & GIT_DIFF_FLAG__TO_DELETE) != 0)
git__free(delta);
}
/* swap new delta list into place */
git_vector_swap(&diff->deltas, &onto);
git_vector_free(&onto);
git_vector_sort(&diff->deltas);
return 0;
on_error:
git_vector_free_deep(&onto);
return -1;
}
GIT_INLINE(git_diff_file *) similarity_get_file(git_diff *diff, size_t idx)
{
git_diff_delta *delta = git_vector_get(&diff->deltas, idx / 2);
return (idx & 1) ? &delta->new_file : &delta->old_file;
}
typedef struct {
size_t idx;
git_iterator_t src;
git_repository *repo;
git_diff_file *file;
git_buf data;
git_odb_object *odb_obj;
git_blob *blob;
} similarity_info;
static int similarity_init(
similarity_info *info, git_diff *diff, size_t file_idx)
{
info->idx = file_idx;
info->src = (file_idx & 1) ? diff->new_src : diff->old_src;
info->repo = diff->repo;
info->file = similarity_get_file(diff, file_idx);
info->odb_obj = NULL;
info->blob = NULL;
git_buf_init(&info->data, 0);
if (info->file->size > 0 || info->src == GIT_ITERATOR_WORKDIR)
return 0;
return git_diff_file__resolve_zero_size(
info->file, &info->odb_obj, info->repo);
}
static int similarity_sig(
similarity_info *info,
const git_diff_find_options *opts,
void **cache)
{
int error = 0;
git_diff_file *file = info->file;
if (info->src == GIT_ITERATOR_WORKDIR) {
if ((error = git_repository_workdir_path(
&info->data, info->repo, file->path)) < 0)
return error;
/* if path is not a regular file, just skip this item */
if (!git_path_isfile(info->data.ptr))
return 0;
/* TODO: apply wd-to-odb filters to file data if necessary */
error = opts->metric->file_signature(
&cache[info->idx], info->file,
info->data.ptr, opts->metric->payload);
} else {
/* if we didn't initially know the size, we might have an odb_obj
* around from earlier, so convert that, otherwise load the blob now
*/
if (info->odb_obj != NULL)
error = git_object__from_odb_object(
(git_object **)&info->blob, info->repo,
info->odb_obj, GIT_OBJECT_BLOB);
else
error = git_blob_lookup(&info->blob, info->repo, &file->id);
if (error < 0) {
/* if lookup fails, just skip this item in similarity calc */
git_error_clear();
} else {
size_t sz;
/* index size may not be actual blob size if filtered */
if (file->size != git_blob_rawsize(info->blob))
file->size = git_blob_rawsize(info->blob);
sz = git__is_sizet(file->size) ? (size_t)file->size : (size_t)-1;
error = opts->metric->buffer_signature(
&cache[info->idx], info->file,
git_blob_rawcontent(info->blob), sz, opts->metric->payload);
}
}
return error;
}
static void similarity_unload(similarity_info *info)
{
if (info->odb_obj)
git_odb_object_free(info->odb_obj);
if (info->blob)
git_blob_free(info->blob);
else
git_buf_dispose(&info->data);
}
#define FLAG_SET(opts,flag_name) (((opts)->flags & flag_name) != 0)
/* - score < 0 means files cannot be compared
* - score >= 100 means files are exact match
* - score == 0 means files are completely different
*/
static int similarity_measure(
int *score,
git_diff *diff,
const git_diff_find_options *opts,
void **cache,
size_t a_idx,
size_t b_idx)
{
git_diff_file *a_file = similarity_get_file(diff, a_idx);
git_diff_file *b_file = similarity_get_file(diff, b_idx);
bool exact_match = FLAG_SET(opts, GIT_DIFF_FIND_EXACT_MATCH_ONLY);
int error = 0;
similarity_info a_info, b_info;
*score = -1;
/* don't try to compare things that aren't files */
if (!GIT_MODE_ISBLOB(a_file->mode) || !GIT_MODE_ISBLOB(b_file->mode))
return 0;
/* if exact match is requested, force calculation of missing OIDs now */
if (exact_match) {
if (git_oid_is_zero(&a_file->id) &&
diff->old_src == GIT_ITERATOR_WORKDIR &&
!git_diff__oid_for_file(&a_file->id,
diff, a_file->path, a_file->mode, a_file->size))
a_file->flags |= GIT_DIFF_FLAG_VALID_ID;
if (git_oid_is_zero(&b_file->id) &&
diff->new_src == GIT_ITERATOR_WORKDIR &&
!git_diff__oid_for_file(&b_file->id,
diff, b_file->path, b_file->mode, b_file->size))
b_file->flags |= GIT_DIFF_FLAG_VALID_ID;
}
/* check OID match as a quick test */
if (git_oid__cmp(&a_file->id, &b_file->id) == 0) {
*score = 100;
return 0;
}
/* don't calculate signatures if we are doing exact match */
if (exact_match) {
*score = 0;
return 0;
}
memset(&a_info, 0, sizeof(a_info));
memset(&b_info, 0, sizeof(b_info));
/* set up similarity data (will try to update missing file sizes) */
if (!cache[a_idx] && (error = similarity_init(&a_info, diff, a_idx)) < 0)
return error;
if (!cache[b_idx] && (error = similarity_init(&b_info, diff, b_idx)) < 0)
goto cleanup;
/* check if file sizes are nowhere near each other */
if (a_file->size > 127 &&
b_file->size > 127 &&
(a_file->size > (b_file->size << 3) ||
b_file->size > (a_file->size << 3)))
goto cleanup;
/* update signature cache if needed */
if (!cache[a_idx]) {
if ((error = similarity_sig(&a_info, opts, cache)) < 0)
goto cleanup;
}
if (!cache[b_idx]) {
if ((error = similarity_sig(&b_info, opts, cache)) < 0)
goto cleanup;
}
/* calculate similarity provided that the metric choose to process
* both the a and b files (some may not if file is too big, etc).
*/
if (cache[a_idx] && cache[b_idx])
error = opts->metric->similarity(
score, cache[a_idx], cache[b_idx], opts->metric->payload);
cleanup:
similarity_unload(&a_info);
similarity_unload(&b_info);
return error;
}
static int calc_self_similarity(
git_diff *diff,
const git_diff_find_options *opts,
size_t delta_idx,
void **cache)
{
int error, similarity = -1;
git_diff_delta *delta = GIT_VECTOR_GET(&diff->deltas, delta_idx);
if ((delta->flags & GIT_DIFF_FLAG__HAS_SELF_SIMILARITY) != 0)
return 0;
error = similarity_measure(
&similarity, diff, opts, cache, 2 * delta_idx, 2 * delta_idx + 1);
if (error < 0)
return error;
if (similarity >= 0) {
delta->similarity = (uint16_t)similarity;
delta->flags |= GIT_DIFF_FLAG__HAS_SELF_SIMILARITY;
}
return 0;
}
static bool is_rename_target(
git_diff *diff,
const git_diff_find_options *opts,
size_t delta_idx,
void **cache)
{
git_diff_delta *delta = GIT_VECTOR_GET(&diff->deltas, delta_idx);
/* skip things that aren't plain blobs */
if (!GIT_MODE_ISBLOB(delta->new_file.mode))
return false;
/* only consider ADDED, RENAMED, COPIED, and split MODIFIED as
* targets; maybe include UNTRACKED if requested.
*/
switch (delta->status) {
case GIT_DELTA_UNMODIFIED:
case GIT_DELTA_DELETED:
case GIT_DELTA_IGNORED:
case GIT_DELTA_CONFLICTED:
return false;
case GIT_DELTA_MODIFIED:
if (!FLAG_SET(opts, GIT_DIFF_FIND_REWRITES) &&
!FLAG_SET(opts, GIT_DIFF_FIND_RENAMES_FROM_REWRITES))
return false;
if (calc_self_similarity(diff, opts, delta_idx, cache) < 0)
return false;
if (FLAG_SET(opts, GIT_DIFF_BREAK_REWRITES) &&
delta->similarity < opts->break_rewrite_threshold) {
delta->flags |= GIT_DIFF_FLAG__TO_SPLIT;
break;
}
if (FLAG_SET(opts, GIT_DIFF_FIND_RENAMES_FROM_REWRITES) &&
delta->similarity < opts->rename_from_rewrite_threshold) {
delta->flags |= GIT_DIFF_FLAG__TO_SPLIT;
break;
}
return false;
case GIT_DELTA_UNTRACKED:
if (!FLAG_SET(opts, GIT_DIFF_FIND_FOR_UNTRACKED))
return false;
break;
default: /* all other status values should be checked */
break;
}
delta->flags |= GIT_DIFF_FLAG__IS_RENAME_TARGET;
return true;
}
static bool is_rename_source(
git_diff *diff,
const git_diff_find_options *opts,
size_t delta_idx,
void **cache)
{
git_diff_delta *delta = GIT_VECTOR_GET(&diff->deltas, delta_idx);
/* skip things that aren't blobs */
if (!GIT_MODE_ISBLOB(delta->old_file.mode))
return false;
switch (delta->status) {
case GIT_DELTA_ADDED:
case GIT_DELTA_UNTRACKED:
case GIT_DELTA_UNREADABLE:
case GIT_DELTA_IGNORED:
case GIT_DELTA_CONFLICTED:
return false;
case GIT_DELTA_DELETED:
case GIT_DELTA_TYPECHANGE:
break;
case GIT_DELTA_UNMODIFIED:
if (!FLAG_SET(opts, GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED))
return false;
if (FLAG_SET(opts, GIT_DIFF_FIND_REMOVE_UNMODIFIED))
delta->flags |= GIT_DIFF_FLAG__TO_DELETE;
break;
default: /* MODIFIED, RENAMED, COPIED */
/* if we're finding copies, this could be a source */
if (FLAG_SET(opts, GIT_DIFF_FIND_COPIES))
break;
/* otherwise, this is only a source if we can split it */
if (!FLAG_SET(opts, GIT_DIFF_FIND_REWRITES) &&
!FLAG_SET(opts, GIT_DIFF_FIND_RENAMES_FROM_REWRITES))
return false;
if (calc_self_similarity(diff, opts, delta_idx, cache) < 0)
return false;
if (FLAG_SET(opts, GIT_DIFF_BREAK_REWRITES) &&
delta->similarity < opts->break_rewrite_threshold) {
delta->flags |= GIT_DIFF_FLAG__TO_SPLIT;
break;
}
if (FLAG_SET(opts, GIT_DIFF_FIND_RENAMES_FROM_REWRITES) &&
delta->similarity < opts->rename_from_rewrite_threshold)
break;
return false;
}
delta->flags |= GIT_DIFF_FLAG__IS_RENAME_SOURCE;
return true;
}
GIT_INLINE(bool) delta_is_split(git_diff_delta *delta)
{
return (delta->status == GIT_DELTA_TYPECHANGE ||
(delta->flags & GIT_DIFF_FLAG__TO_SPLIT) != 0);
}
GIT_INLINE(bool) delta_is_new_only(git_diff_delta *delta)
{
return (delta->status == GIT_DELTA_ADDED ||
delta->status == GIT_DELTA_UNTRACKED ||
delta->status == GIT_DELTA_UNREADABLE ||
delta->status == GIT_DELTA_IGNORED);
}
GIT_INLINE(void) delta_make_rename(
git_diff_delta *to, const git_diff_delta *from, uint16_t similarity)
{
to->status = GIT_DELTA_RENAMED;
to->similarity = similarity;
to->nfiles = 2;
memcpy(&to->old_file, &from->old_file, sizeof(to->old_file));
to->flags &= ~GIT_DIFF_FLAG__TO_SPLIT;
}
typedef struct {
size_t idx;
uint16_t similarity;
} diff_find_match;
int git_diff_find_similar(
git_diff *diff,
const git_diff_find_options *given_opts)
{
size_t s, t;
int error = 0, result;
uint16_t similarity;
git_diff_delta *src, *tgt;
git_diff_find_options opts = GIT_DIFF_FIND_OPTIONS_INIT;
size_t num_deltas, num_srcs = 0, num_tgts = 0;
size_t tried_srcs = 0, tried_tgts = 0;
size_t num_rewrites = 0, num_updates = 0, num_bumped = 0;
size_t sigcache_size;
void **sigcache = NULL; /* cache of similarity metric file signatures */
diff_find_match *tgt2src = NULL;
diff_find_match *src2tgt = NULL;
diff_find_match *tgt2src_copy = NULL;
diff_find_match *best_match;
git_diff_file swap;
GIT_ASSERT_ARG(diff);
if ((error = normalize_find_opts(diff, &opts, given_opts)) < 0)
return error;
num_deltas = diff->deltas.length;
/* TODO: maybe abort if deltas.length > rename_limit ??? */
if (!num_deltas || !git__is_uint32(num_deltas))
goto cleanup;
/* No flags set; nothing to do */
if ((opts.flags & GIT_DIFF_FIND_ALL) == 0)
goto cleanup;
GIT_ERROR_CHECK_ALLOC_MULTIPLY(&sigcache_size, num_deltas, 2);
sigcache = git__calloc(sigcache_size, sizeof(void *));
GIT_ERROR_CHECK_ALLOC(sigcache);
/* Label rename sources and targets
*
* This will also set self-similarity scores for MODIFIED files and
* mark them for splitting if break-rewrites is enabled
*/
git_vector_foreach(&diff->deltas, t, tgt) {
if (is_rename_source(diff, &opts, t, sigcache))
++num_srcs;
if (is_rename_target(diff, &opts, t, sigcache))
++num_tgts;
if ((tgt->flags & GIT_DIFF_FLAG__TO_SPLIT) != 0)
num_rewrites++;
}
/* if there are no candidate srcs or tgts, we're done */
if (!num_srcs || !num_tgts)
goto cleanup;
src2tgt = git__calloc(num_deltas, sizeof(diff_find_match));
GIT_ERROR_CHECK_ALLOC(src2tgt);
tgt2src = git__calloc(num_deltas, sizeof(diff_find_match));
GIT_ERROR_CHECK_ALLOC(tgt2src);
if (FLAG_SET(&opts, GIT_DIFF_FIND_COPIES)) {
tgt2src_copy = git__calloc(num_deltas, sizeof(diff_find_match));
GIT_ERROR_CHECK_ALLOC(tgt2src_copy);
}
/*
* Find best-fit matches for rename / copy candidates
*/
find_best_matches:
tried_tgts = num_bumped = 0;
git_vector_foreach(&diff->deltas, t, tgt) {
/* skip things that are not rename targets */
if ((tgt->flags & GIT_DIFF_FLAG__IS_RENAME_TARGET) == 0)
continue;
tried_srcs = 0;
git_vector_foreach(&diff->deltas, s, src) {
/* skip things that are not rename sources */
if ((src->flags & GIT_DIFF_FLAG__IS_RENAME_SOURCE) == 0)
continue;
/* calculate similarity for this pair and find best match */
if (s == t)
result = -1; /* don't measure self-similarity here */
else if ((error = similarity_measure(
&result, diff, &opts, sigcache, 2 * s, 2 * t + 1)) < 0)
goto cleanup;
if (result < 0)
continue;
similarity = (uint16_t)result;
/* is this a better rename? */
if (tgt2src[t].similarity < similarity &&
src2tgt[s].similarity < similarity)
{
/* eject old mapping */
if (src2tgt[s].similarity > 0) {
tgt2src[src2tgt[s].idx].similarity = 0;
num_bumped++;
}
if (tgt2src[t].similarity > 0) {
src2tgt[tgt2src[t].idx].similarity = 0;
num_bumped++;
}
/* write new mapping */
tgt2src[t].idx = s;
tgt2src[t].similarity = similarity;
src2tgt[s].idx = t;
src2tgt[s].similarity = similarity;
}
/* keep best absolute match for copies */
if (tgt2src_copy != NULL &&
tgt2src_copy[t].similarity < similarity)
{
tgt2src_copy[t].idx = s;
tgt2src_copy[t].similarity = similarity;
}
if (++tried_srcs >= num_srcs)
break;
/* cap on maximum targets we'll examine (per "tgt" file) */
if (tried_srcs > opts.rename_limit)
break;
}
if (++tried_tgts >= num_tgts)
break;
}
if (num_bumped > 0) /* try again if we bumped some items */
goto find_best_matches;
/*
* Rewrite the diffs with renames / copies
*/
git_vector_foreach(&diff->deltas, t, tgt) {
/* skip things that are not rename targets */
if ((tgt->flags & GIT_DIFF_FLAG__IS_RENAME_TARGET) == 0)
continue;
/* check if this delta was the target of a similarity */
if (tgt2src[t].similarity)
best_match = &tgt2src[t];
else if (tgt2src_copy && tgt2src_copy[t].similarity)
best_match = &tgt2src_copy[t];
else
continue;
s = best_match->idx;
src = GIT_VECTOR_GET(&diff->deltas, s);
/* possible scenarios:
* 1. from DELETE to ADD/UNTRACK/IGNORE = RENAME
* 2. from DELETE to SPLIT/TYPECHANGE = RENAME + DELETE
* 3. from SPLIT/TYPECHANGE to ADD/UNTRACK/IGNORE = ADD + RENAME
* 4. from SPLIT/TYPECHANGE to SPLIT/TYPECHANGE = RENAME + SPLIT
* 5. from OTHER to ADD/UNTRACK/IGNORE = OTHER + COPY
*/
if (src->status == GIT_DELTA_DELETED) {
if (delta_is_new_only(tgt)) {
if (best_match->similarity < opts.rename_threshold)
continue;
delta_make_rename(tgt, src, best_match->similarity);
src->flags |= GIT_DIFF_FLAG__TO_DELETE;
num_rewrites++;
} else {
GIT_ASSERT(delta_is_split(tgt));
if (best_match->similarity < opts.rename_from_rewrite_threshold)
continue;
memcpy(&swap, &tgt->old_file, sizeof(swap));
delta_make_rename(tgt, src, best_match->similarity);
num_rewrites--;
GIT_ASSERT(src->status == GIT_DELTA_DELETED);
memcpy(&src->old_file, &swap, sizeof(src->old_file));
memset(&src->new_file, 0, sizeof(src->new_file));
src->new_file.path = src->old_file.path;
src->new_file.flags |= GIT_DIFF_FLAG_VALID_ID;
num_updates++;
if (src2tgt[t].similarity > 0 && src2tgt[t].idx > t) {