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More git_diff_find_similar improvements

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- Add new GIT_DIFF_FIND_EXACT_MATCH_ONLY flag to do similarity
  matching without using the similarity metric (i.e. only compare
  the SHA).
- Clean up the similarity measurement code to more rigorously
  distinguish between files that are not similar and files that
  are not comparable (previously, a 0 could either mean that the
  files could not be compared or that they were totally different)
- When splitting a MODIFIED file into a DELETE/ADD pair, actually
  make a DELETED/UNTRACKED pair if the right side of the diff is
  from the working directory.  This prevents an odd mix of ADDED
  and UNTRACKED files on workdir diffs.
This commit is contained in:
Russell Belfer 2013-05-20 13:37:21 -07:00
parent 5c8f37a397
commit 9be5be47fb
3 changed files with 101 additions and 71 deletions
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2
include/git2/diff.h
View File

@ -441,6 +441,8 @@ typedef enum {
GIT_DIFF_FIND_IGNORE_WHITESPACE = (1 << 12),
/** measure similarity including all data */
GIT_DIFF_FIND_DONT_IGNORE_WHITESPACE = (1 << 13),
/** measure similarity only by comparing SHAs (fast and cheap) */
GIT_DIFF_FIND_EXACT_MATCH_ONLY = (1 << 14),
} git_diff_find_t;
/**

169
src/diff_tform.c
View File

@ -255,6 +255,16 @@ static int normalize_find_opts(
/* 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;
@ -373,7 +383,10 @@ static int apply_splits_and_deletes(
if (git_vector_insert(&onto, deleted) < 0)
goto on_error;
delta->status = GIT_DELTA_ADDED;
if (diff->new_src == GIT_ITERATOR_TYPE_WORKDIR)
delta->status = GIT_DELTA_UNTRACKED;
else
delta->status = GIT_DELTA_ADDED;
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_OID;
@ -460,22 +473,56 @@ static int similarity_calc(
return error;
}
#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_list *diff,
git_diff_find_options *opts,
void **cache,
size_t a_idx,
size_t b_idx)
{
int score = 0;
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);
*score = -1;
/* don't try to compare files of different types */
if (GIT_MODE_TYPE(a_file->mode) != GIT_MODE_TYPE(b_file->mode))
return 0;
if (git_oid__cmp(&a_file->oid, &b_file->oid) == 0)
return 100;
/* if exact match is requested, force calculation of missing OIDs */
if (exact_match) {
if (git_oid_iszero(&a_file->oid) &&
diff->old_src == GIT_ITERATOR_TYPE_WORKDIR &&
!git_diff__oid_for_file(diff->repo, a_file->path,
a_file->mode, a_file->size, &a_file->oid))
a_file->flags |= GIT_DIFF_FLAG_VALID_OID;
if (git_oid_iszero(&b_file->oid) &&
diff->new_src == GIT_ITERATOR_TYPE_WORKDIR &&
!git_diff__oid_for_file(diff->repo, b_file->path,
b_file->mode, b_file->size, &b_file->oid))
b_file->flags |= GIT_DIFF_FLAG_VALID_OID;
}
/* check OID match as a quick test */
if (git_oid__cmp(&a_file->oid, &b_file->oid) == 0) {
*score = 100;
return 0;
}
/* don't calculate signatures if we are doing exact match */
if (exact_match) {
*score = 0;
return 0;
}
/* update signature cache if needed */
if (!cache[a_idx] && similarity_calc(diff, opts, a_idx, cache) < 0)
@ -488,20 +535,33 @@ static int similarity_measure(
return 0;
/* compare signatures */
if (opts->metric->similarity(
&score, cache[a_idx], cache[b_idx], opts->metric->payload) < 0)
return -1;
/* clip score */
if (score < 1)
score = 1; /* zero means uncomparable, so use 1 for least similar */
else if (score > 100)
score = 100;
return score;
return opts->metric->similarity(
score, cache[a_idx], cache[b_idx], opts->metric->payload);
}
#define FLAG_SET(opts,flag_name) ((opts.flags & flag_name) != 0)
static void convert_to_rename_and_add(
git_diff_list *diff,
git_diff_delta *from,
git_diff_delta *to,
int similarity)
{
to->status = GIT_DELTA_RENAMED;
to->flags &= ~GIT_DIFF_FLAG__TO_SPLIT; /* ensure no split */
to->similarity = (uint32_t)similarity;
memcpy(&to->old_file, &from->old_file, sizeof(to->old_file));
validate_delta(to);
if (diff->new_src == GIT_ITERATOR_TYPE_WORKDIR)
from->status = GIT_DELTA_UNTRACKED;
else
from->status = GIT_DELTA_ADDED;
from->flags &= ~GIT_DIFF_FLAG__TO_SPLIT; /* ensure no split */
from->similarity = 0;
memset(&from->old_file, 0, sizeof(from->old_file));
from->old_file.path = from->new_file.path;
from->old_file.flags |= GIT_DIFF_FLAG_VALID_OID;
validate_delta(from);
}
typedef struct {
uint32_t idx;
@ -542,21 +602,17 @@ int git_diff_find_similar(
continue;
/* skip things that aren't plain blobs */
if (GIT_MODE_TYPE(from->old_file.mode) !=
GIT_MODE_TYPE(GIT_FILEMODE_BLOB))
if (!GIT_MODE_ISBLOB(from->old_file.mode))
continue;
/* measure similarity from old_file to new_file */
similarity = similarity_measure(
diff, &opts, cache, 2 * i, 2 * i + 1);
if (similarity < 0) {
error = similarity;
if ((error = similarity_measure(
&similarity, diff, &opts, cache, 2 * i, 2 * i + 1)) < 0)
goto cleanup;
}
if (similarity > 0 &&
similarity < (int)opts.break_rewrite_threshold) {
if (similarity < 0)
continue;
if (similarity < (int)opts.break_rewrite_threshold) {
from->similarity = (uint32_t)similarity;
from->flags |= GIT_DIFF_FLAG__TO_SPLIT;
num_rewrites++;
@ -573,8 +629,7 @@ int git_diff_find_similar(
matches[i].similarity = 0;
/* skip things that aren't plain blobs */
if (GIT_MODE_TYPE(from->old_file.mode) !=
GIT_MODE_TYPE(GIT_FILEMODE_BLOB))
if (!GIT_MODE_ISBLOB(from->old_file.mode))
continue;
/* don't check UNMODIFIED files as source unless given option */
@ -599,8 +654,7 @@ int git_diff_find_similar(
continue;
/* skip things that aren't blobs */
if (GIT_MODE_TYPE(to->new_file.mode) !=
GIT_MODE_TYPE(GIT_FILEMODE_BLOB))
if (!GIT_MODE_ISBLOB(to->new_file.mode))
continue;
/* only consider ADDED, RENAMED, COPIED, and split MODIFIED as
@ -630,14 +684,13 @@ int git_diff_find_similar(
break;
/* calculate similarity for this pair and find best match */
similarity = similarity_measure(
diff, &opts, cache, 2 * i, 2 * j + 1);
if (similarity < 0) {
error = similarity;
if ((error = similarity_measure(
&similarity, diff, &opts, cache, 2 * i, 2 * j + 1)) < 0)
goto cleanup;
if (similarity < 0) {
--tried_targets;
continue;
}
if (matches[i].similarity < (uint32_t)similarity) {
matches[i].similarity = (uint32_t)similarity;
matches[i].idx = j;
@ -687,18 +740,7 @@ int git_diff_find_similar(
if (similarity < (int)opts.rename_threshold)
continue;
to->status = GIT_DELTA_RENAMED;
to->similarity = (uint32_t)similarity;
memcpy(&to->old_file, &from->old_file, sizeof(to->old_file));
validate_delta(to);
from->status = GIT_DELTA_ADDED;
from->flags &= ~GIT_DIFF_FLAG__TO_SPLIT;
from->similarity = 0; /* reset self-similarity */
memset(&from->old_file, 0, sizeof(from->old_file));
from->old_file.path = from->new_file.path;
validate_delta(from);
convert_to_rename_and_add(diff, from, to, similarity);
num_rewrites--;
num_updates++;
continue;
@ -712,28 +754,16 @@ int git_diff_find_similar(
FLAG_SET(opts, GIT_DIFF_FIND_RENAMES_FROM_REWRITES) &&
similarity > (int)opts.rename_threshold)
{
int self_similarity = similarity_measure(
diff, &opts, cache, 2 * i, 2 * i + 1);
if (self_similarity < 0) {
error = self_similarity;
int self_similarity;
if ((error = similarity_measure(&self_similarity,
diff, &opts, cache, 2 * i, 2 * i + 1)) < 0)
goto cleanup;
}
if (self_similarity < (int)opts.rename_from_rewrite_threshold) {
to->status = GIT_DELTA_RENAMED;
to->flags &= ~GIT_DIFF_FLAG__TO_SPLIT; /* ensure no split */
to->similarity = (uint32_t)similarity;
memcpy(&to->old_file, &from->old_file, sizeof(to->old_file));
validate_delta(to);
from->status = GIT_DELTA_ADDED;
from->flags &= ~GIT_DIFF_FLAG__TO_SPLIT; /* ensure no split */
from->similarity = 0;
memset(&from->old_file, 0, sizeof(from->old_file));
from->old_file.path = from->new_file.path;
from->old_file.flags |= GIT_DIFF_FLAG_VALID_OID;
validate_delta(from);
if (self_similarity >= 0 &&
self_similarity < (int)opts.rename_from_rewrite_threshold) {
convert_to_rename_and_add(diff, from, to, similarity);
num_updates++;
continue;
}
@ -754,13 +784,10 @@ int git_diff_find_similar(
num_updates++;
}
if (num_rewrites > 0) {
assert(num_rewrites < diff->deltas.length);
if (num_rewrites > 0)
error = apply_splits_and_deletes(
diff, diff->deltas.length - num_rewrites,
FLAG_SET(opts, GIT_DIFF_BREAK_REWRITES));
}
if (num_rewrites > 0 || num_updates > 0)
git_vector_sort(&diff->deltas);

1
src/fileops.h
View File

@ -223,6 +223,7 @@ extern git_off_t git_futils_filesize(git_file fd);
#define GIT_MODE_PERMS_MASK 0777
#define GIT_CANONICAL_PERMS(MODE) (((MODE) & 0100) ? 0755 : 0644)
#define GIT_MODE_TYPE(MODE) ((MODE) & ~GIT_MODE_PERMS_MASK)
#define GIT_MODE_ISBLOB(MODE) (GIT_MODE_TYPE(MODE) == GIT_MODE_TYPE(GIT_FILEMODE_BLOB))
/**
* Convert a mode_t from the OS to a legal git mode_t value.