[thirdparty/git.git] / diffcore-rename.c

/*
 * Copyright (C) 2005 Junio C Hamano
 */
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
#include "delta.h"
#include "count-delta.h"

/* Table of rename/copy destinations */

static struct diff_rename_dst {
	struct diff_filespec *two;
	struct diff_filepair *pair;
} *rename_dst;
static int rename_dst_nr, rename_dst_alloc;

static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
						 int insert_ok)
{
	int first, last;

	first = 0;
	last = rename_dst_nr;
	while (last > first) {
		int next = (last + first) >> 1;
		struct diff_rename_dst *dst = &(rename_dst[next]);
		int cmp = strcmp(two->path, dst->two->path);
		if (!cmp)
			return dst;
		if (cmp < 0) {
			last = next;
			continue;
		}
		first = next+1;
	}
	/* not found */
	if (!insert_ok)
		return NULL;
	/* insert to make it at "first" */
	if (rename_dst_alloc <= rename_dst_nr) {
		rename_dst_alloc = alloc_nr(rename_dst_alloc);
		rename_dst = xrealloc(rename_dst,
				      rename_dst_alloc * sizeof(*rename_dst));
	}
	rename_dst_nr++;
	if (first < rename_dst_nr)
		memmove(rename_dst + first + 1, rename_dst + first,
			(rename_dst_nr - first - 1) * sizeof(*rename_dst));
	rename_dst[first].two = two;
	rename_dst[first].pair = NULL;
	return &(rename_dst[first]);
}

/* Table of rename/copy src files */
static struct diff_rename_src {
	struct diff_filespec *one;
	unsigned src_stays : 1;
} *rename_src;
static int rename_src_nr, rename_src_alloc;

static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
						   int src_stays)
{
	int first, last;

	first = 0;
	last = rename_src_nr;
	while (last > first) {
		int next = (last + first) >> 1;
		struct diff_rename_src *src = &(rename_src[next]);
		int cmp = strcmp(one->path, src->one->path);
		if (!cmp)
			return src;
		if (cmp < 0) {
			last = next;
			continue;
		}
		first = next+1;
	}

	/* insert to make it at "first" */
	if (rename_src_alloc <= rename_src_nr) {
		rename_src_alloc = alloc_nr(rename_src_alloc);
		rename_src = xrealloc(rename_src,
				      rename_src_alloc * sizeof(*rename_src));
	}
	rename_src_nr++;
	if (first < rename_src_nr)
		memmove(rename_src + first + 1, rename_src + first,
			(rename_src_nr - first - 1) * sizeof(*rename_src));
	rename_src[first].one = one;
	rename_src[first].src_stays = src_stays;
	return &(rename_src[first]);
}

static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst)
{
	if (src->sha1_valid && dst->sha1_valid &&
	    !memcmp(src->sha1, dst->sha1, 20))
		return 1;
	if (diff_populate_filespec(src) || diff_populate_filespec(dst))
		/* this is an error but will be caught downstream */
		return 0;
	if (src->size == dst->size &&
	    !memcmp(src->data, dst->data, src->size))
		return 1;
	return 0;
}

struct diff_score {
	int src; /* index in rename_src */
	int dst; /* index in rename_dst */
	int score;
};

static int estimate_similarity(struct diff_filespec *src,
			       struct diff_filespec *dst,
			       int minimum_score)
{
	/* src points at a file that existed in the original tree (or
	 * optionally a file in the destination tree) and dst points
	 * at a newly created file.  They may be quite similar, in which
	 * case we want to say src is renamed to dst or src is copied into
	 * dst, and then some edit has been applied to dst.
	 *
	 * Compare them and return how similar they are, representing
	 * the score as an integer between 0 and 10000, except
	 * where they match exactly it is considered better than anything
	 * else.
	 */
	void *delta;
	unsigned long delta_size, base_size;
	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;

	delta_size = ((src->size < dst->size) ?
		      (dst->size - src->size) : (src->size - dst->size));
	base_size = ((src->size < dst->size) ? src->size : dst->size);

	/* We would not consider edits that change the file size so
	 * drastically.  delta_size must be smaller than
	 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
	 * Note that base_size == 0 case is handled here already
	 * and the final score computation below would not have a
	 * divide-by-zero issue.
	 */
	if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
		return 0;

	delta = diff_delta(src->data, src->size,
			   dst->data, dst->size,
			   &delta_size);

	/* A delta that has a lot of literal additions would have
	 * big delta_size no matter what else it does.
	 */
	if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
		return 0;

	/* Estimate the edit size by interpreting delta. */
	delta_size = count_delta(delta, delta_size);
	free(delta);
	if (delta_size == UINT_MAX)
		return 0;

	/*
	 * Now we will give some score to it.  100% edit gets 0 points
	 * and 0% edit gets MAX_SCORE points.
	 */
	score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); 
	if (score < 0) return 0;
	if (MAX_SCORE < score) return MAX_SCORE;
	return score;
}

static void record_rename_pair(struct diff_queue_struct *renq,
			       int dst_index, int src_index, int score)
{
	struct diff_filespec *one, *two, *src, *dst;
	struct diff_filepair *dp;

	if (rename_dst[dst_index].pair)
		die("internal error: dst already matched.");

	src = rename_src[src_index].one;
	one = alloc_filespec(src->path);
	fill_filespec(one, src->sha1, src->mode);

	dst = rename_dst[dst_index].two;
	two = alloc_filespec(dst->path);
	fill_filespec(two, dst->sha1, dst->mode);

	dp = diff_queue(renq, one, two);
	dp->score = score ? : 1; /* make sure it is at least 1 */
	dp->source_stays = rename_src[src_index].src_stays;
	rename_dst[dst_index].pair = dp;
}

/*
 * We sort the rename similarity matrix with the score, in descending
 * order (the most similar first).
 */
static int score_compare(const void *a_, const void *b_)
{
	const struct diff_score *a = a_, *b = b_;
	return b->score - a->score;
}

int diff_scoreopt_parse(const char *opt)
{
	int diglen, num, scale, i;
	if (opt[0] != '-' || (opt[1] != 'M' && opt[1] != 'C'))
		return -1; /* that is not a -M nor -C option */
	diglen = strspn(opt+2, "0123456789");
	if (diglen == 0 || strlen(opt+2) != diglen)
		return 0; /* use default */
	sscanf(opt+2, "%d", &num);
	for (i = 0, scale = 1; i < diglen; i++)
		scale *= 10;

	/* user says num divided by scale and we say internally that
	 * is MAX_SCORE * num / scale.
	 */
	return MAX_SCORE * num / scale;
}

void diffcore_rename(int detect_rename, int minimum_score)
{
	struct diff_queue_struct *q = &diff_queued_diff;
	struct diff_queue_struct renq, outq;
	struct diff_score *mx;
	int i, j;
	int num_create, num_src, dst_cnt;

	if (!minimum_score)
		minimum_score = DEFAULT_MINIMUM_SCORE;
	renq.queue = NULL;
	renq.nr = renq.alloc = 0;

	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
				locate_rename_dst(p->two, 1);
		else if (!DIFF_FILE_VALID(p->two))
			register_rename_src(p->one, 0);
		else if (detect_rename == DIFF_DETECT_COPY)
			register_rename_src(p->one, 1);
	}
	if (rename_dst_nr == 0)
		goto cleanup; /* nothing to do */

	/* We really want to cull the candidates list early
	 * with cheap tests in order to avoid doing deltas.
	 */
	for (i = 0; i < rename_dst_nr; i++) {
		struct diff_filespec *two = rename_dst[i].two;
		for (j = 0; j < rename_src_nr; j++) {
			struct diff_filespec *one = rename_src[j].one;
			if (!is_exact_match(one, two))
				continue;
			record_rename_pair(&renq, i, j, MAX_SCORE);
			break; /* we are done with this entry */
		}
	}
	diff_debug_queue("done detecting exact", &renq);

	/* Have we run out the created file pool?  If so we can avoid
	 * doing the delta matrix altogether.
	 */
	if (renq.nr == rename_dst_nr)
		goto cleanup;

	num_create = (rename_dst_nr - renq.nr);
	num_src = rename_src_nr;
	mx = xmalloc(sizeof(*mx) * num_create * num_src);
	for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
		int base = dst_cnt * num_src;
		struct diff_filespec *two = rename_dst[i].two;
		if (rename_dst[i].pair)
			continue; /* dealt with exact match already. */
		for (j = 0; j < rename_src_nr; j++) {
			struct diff_filespec *one = rename_src[j].one;
			struct diff_score *m = &mx[base+j];
			m->src = j;
			m->dst = i;
			m->score = estimate_similarity(one, two,
						       minimum_score);
		}
		dst_cnt++;
	}
	/* cost matrix sorted by most to least similar pair */
	qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
	for (i = 0; i < num_create * num_src; i++) {
		struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
		if (dst->pair)
			continue; /* already done, either exact or fuzzy. */
		if (mx[i].score < minimum_score)
			break; /* there is no more usable pair. */
		record_rename_pair(&renq, mx[i].dst, mx[i].src, mx[i].score);
	}
	free(mx);
	diff_debug_queue("done detecting fuzzy", &renq);

 cleanup:
	/* At this point, we have found some renames and copies and they
	 * are kept in renq.  The original list is still in *q.
	 */
	outq.queue = NULL;
	outq.nr = outq.alloc = 0;
	for (i = 0; i < q->nr; i++) {
		struct diff_filepair *p = q->queue[i];
		struct diff_rename_dst *dst = locate_rename_dst(p->two, 0);
		struct diff_filepair *pair_to_free = NULL;

		if (dst) {
			/* creation */
			if (dst->pair) {
				/* renq has rename/copy to produce
				 * this file already, so we do not
				 * emit the creation record in the
				 * output.
				 */
				diff_q(&outq, dst->pair);
				pair_to_free = p;
			}
			else
				/* no matching rename/copy source, so record
				 * this as a creation.
				 */
				diff_q(&outq, p);
		}
		else if (!diff_unmodified_pair(p))
			/* all the usual ones need to be kept */
			diff_q(&outq, p);
		else
			/* no need to keep unmodified pairs */
			pair_to_free = p;

		if (pair_to_free)
			diff_free_filepair(pair_to_free);
	}
	diff_debug_queue("done copying original", &outq);

	free(renq.queue);
	free(q->queue);
	*q = outq;
	diff_debug_queue("done collapsing", q);

	free(rename_dst);
	rename_dst = NULL;
	rename_dst_nr = rename_dst_alloc = 0;
	free(rename_src);
	rename_src = NULL;
	rename_src_nr = rename_src_alloc = 0;
	return;
}
Commit	Line	Data
427dcb4b JH	1	/*
	2	* Copyright (C) 2005 Junio C Hamano
	3	*/
	4	#include "cache.h"
	5	#include "diff.h"
	6	#include "diffcore.h"
	7	#include "delta.h"
85976974	8	#include "count-delta.h"
427dcb4b	9
25d5ea41 JH	10	/* Table of rename/copy destinations */
	11
	12	static struct diff_rename_dst {
	13	struct diff_filespec *two;
	14	struct diff_filepair *pair;
	15	} *rename_dst;
	16	static int rename_dst_nr, rename_dst_alloc;
427dcb4b	17
25d5ea41 JH	18	static struct diff_rename_dst locate_rename_dst(struct diff_filespec two,
25d5ea41 JH	19	int insert_ok)
427dcb4b	20	{
25d5ea41 JH	21	int first, last;
	22
	23	first = 0;
	24	last = rename_dst_nr;
	25	while (last > first) {
	26	int next = (last + first) >> 1;
	27	struct diff_rename_dst *dst = &(rename_dst[next]);
	28	int cmp = strcmp(two->path, dst->two->path);
	29	if (!cmp)
	30	return dst;
	31	if (cmp < 0) {
	32	last = next;
	33	continue;
	34	}
	35	first = next+1;
	36	}
	37	/* not found */
	38	if (!insert_ok)
	39	return NULL;
	40	/* insert to make it at "first" */
	41	if (rename_dst_alloc <= rename_dst_nr) {
	42	rename_dst_alloc = alloc_nr(rename_dst_alloc);
	43	rename_dst = xrealloc(rename_dst,
	44	rename_dst_alloc * sizeof(*rename_dst));
	45	}
	46	rename_dst_nr++;
	47	if (first < rename_dst_nr)
	48	memmove(rename_dst + first + 1, rename_dst + first,
	49	(rename_dst_nr - first - 1) * sizeof(*rename_dst));
	50	rename_dst[first].two = two;
	51	rename_dst[first].pair = NULL;
	52	return &(rename_dst[first]);
427dcb4b JH	53	}
427dcb4b JH	54
15d061b4	55	/* Table of rename/copy src files */
25d5ea41 JH	56	static struct diff_rename_src {
25d5ea41 JH	57	struct diff_filespec *one;
15d061b4	58	unsigned src_stays : 1;
25d5ea41 JH	59	} *rename_src;
25d5ea41 JH	60	static int rename_src_nr, rename_src_alloc;
427dcb4b	61
15d061b4 JH	62	static struct diff_rename_src register_rename_src(struct diff_filespec one,
15d061b4 JH	63	int src_stays)
25d5ea41 JH	64	{
	65	int first, last;
	66
	67	first = 0;
	68	last = rename_src_nr;
	69	while (last > first) {
	70	int next = (last + first) >> 1;
	71	struct diff_rename_src *src = &(rename_src[next]);
	72	int cmp = strcmp(one->path, src->one->path);
	73	if (!cmp)
	74	return src;
	75	if (cmp < 0) {
	76	last = next;
	77	continue;
	78	}
	79	first = next+1;
	80	}
15d061b4	81
25d5ea41 JH	82	/* insert to make it at "first" */
	83	if (rename_src_alloc <= rename_src_nr) {
	84	rename_src_alloc = alloc_nr(rename_src_alloc);
	85	rename_src = xrealloc(rename_src,
	86	rename_src_alloc * sizeof(*rename_src));
427dcb4b	87	}
25d5ea41 JH	88	rename_src_nr++;
	89	if (first < rename_src_nr)
	90	memmove(rename_src + first + 1, rename_src + first,
	91	(rename_src_nr - first - 1) * sizeof(*rename_src));
	92	rename_src[first].one = one;
15d061b4	93	rename_src[first].src_stays = src_stays;
25d5ea41	94	return &(rename_src[first]);
427dcb4b JH	95	}
	96
	97	static int is_exact_match(struct diff_filespec src, struct diff_filespec dst)
	98	{
	99	if (src->sha1_valid && dst->sha1_valid &&
	100	!memcmp(src->sha1, dst->sha1, 20))
	101	return 1;
	102	if (diff_populate_filespec(src) \|\| diff_populate_filespec(dst))
	103	/* this is an error but will be caught downstream */
	104	return 0;
	105	if (src->size == dst->size &&
	106	!memcmp(src->data, dst->data, src->size))
	107	return 1;
	108	return 0;
	109	}
	110
	111	struct diff_score {
25d5ea41 JH	112	int src; /* index in rename_src */
25d5ea41 JH	113	int dst; /* index in rename_dst */
427dcb4b	114	int score;
427dcb4b JH	115	};
	116
	117	static int estimate_similarity(struct diff_filespec *src,
	118	struct diff_filespec *dst,
	119	int minimum_score)
	120	{
	121	/* src points at a file that existed in the original tree (or
	122	* optionally a file in the destination tree) and dst points
	123	* at a newly created file. They may be quite similar, in which
	124	* case we want to say src is renamed to dst or src is copied into
	125	* dst, and then some edit has been applied to dst.
	126	*
	127	* Compare them and return how similar they are, representing
	128	* the score as an integer between 0 and 10000, except
	129	* where they match exactly it is considered better than anything
	130	* else.
	131	*/
	132	void *delta;
58b103f5	133	unsigned long delta_size, base_size;
427dcb4b JH	134	int score;
427dcb4b JH	135
60896c7b JH	136	/* We deal only with regular files. Symlink renames are handled
	137	* only when they are exact matches --- in other words, no edits
	138	* after renaming.
	139	*/
	140	if (!S_ISREG(src->mode) \|\| !S_ISREG(dst->mode))
	141	return 0;
	142
427dcb4b JH	143	delta_size = ((src->size < dst->size) ?
427dcb4b JH	144	(dst->size - src->size) : (src->size - dst->size));
58b103f5	145	base_size = ((src->size < dst->size) ? src->size : dst->size);
427dcb4b	146
58b103f5 JH	147	/* We would not consider edits that change the file size so
58b103f5 JH	148	* drastically. delta_size must be smaller than
cd1870ed	149	* (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
58b103f5 JH	150	* Note that base_size == 0 case is handled here already
	151	* and the final score computation below would not have a
	152	* divide-by-zero issue.
427dcb4b	153	*/
cd1870ed	154	if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
427dcb4b JH	155	return 0;
	156
	157	delta = diff_delta(src->data, src->size,
	158	dst->data, dst->size,
	159	&delta_size);
85976974 JH	160
	161	/* A delta that has a lot of literal additions would have
	162	* big delta_size no matter what else it does.
58b103f5	163	*/
a00d7d10	164	if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
85976974 JH	165	return 0;
	166
	167	/* Estimate the edit size by interpreting delta. */
	168	delta_size = count_delta(delta, delta_size);
427dcb4b	169	free(delta);
85976974 JH	170	if (delta_size == UINT_MAX)
85976974 JH	171	return 0;
427dcb4b	172
58b103f5 JH	173	/*
	174	* Now we will give some score to it. 100% edit gets 0 points
	175	* and 0% edit gets MAX_SCORE points.
427dcb4b	176	*/
58b103f5	177	score = MAX_SCORE - (MAX_SCORE * delta_size / base_size);
427dcb4b JH	178	if (score < 0) return 0;
	179	if (MAX_SCORE < score) return MAX_SCORE;
	180	return score;
	181	}
	182
25d5ea41 JH	183	static void record_rename_pair(struct diff_queue_struct *renq,
25d5ea41 JH	184	int dst_index, int src_index, int score)
427dcb4b	185	{
25d5ea41 JH	186	struct diff_filespec one, two, src, dst;
25d5ea41 JH	187	struct diff_filepair *dp;
f7c1512a	188
25d5ea41 JH	189	if (rename_dst[dst_index].pair)
25d5ea41 JH	190	die("internal error: dst already matched.");
427dcb4b	191
25d5ea41 JH	192	src = rename_src[src_index].one;
	193	one = alloc_filespec(src->path);
	194	fill_filespec(one, src->sha1, src->mode);
427dcb4b	195
25d5ea41 JH	196	dst = rename_dst[dst_index].two;
	197	two = alloc_filespec(dst->path);
	198	fill_filespec(two, dst->sha1, dst->mode);
427dcb4b	199
25d5ea41	200	dp = diff_queue(renq, one, two);
15d061b4 JH	201	dp->score = score ? : 1; /* make sure it is at least 1 */
15d061b4 JH	202	dp->source_stays = rename_src[src_index].src_stays;
25d5ea41	203	rename_dst[dst_index].pair = dp;
427dcb4b JH	204	}
	205
	206	/*
	207	* We sort the rename similarity matrix with the score, in descending
15d061b4	208	* order (the most similar first).
427dcb4b JH	209	*/
	210	static int score_compare(const void a_, const void b_)
	211	{
	212	const struct diff_score a = a_, b = b_;
	213	return b->score - a->score;
	214	}
	215
6b14d7fa JH	216	int diff_scoreopt_parse(const char *opt)
	217	{
	218	int diglen, num, scale, i;
	219	if (opt[0] != '-' \|\| (opt[1] != 'M' && opt[1] != 'C'))
	220	return -1; /* that is not a -M nor -C option */
	221	diglen = strspn(opt+2, "0123456789");
	222	if (diglen == 0 \|\| strlen(opt+2) != diglen)
	223	return 0; /* use default */
	224	sscanf(opt+2, "%d", &num);
	225	for (i = 0, scale = 1; i < diglen; i++)
	226	scale *= 10;
	227
	228	/* user says num divided by scale and we say internally that
	229	* is MAX_SCORE * num / scale.
	230	*/
	231	return MAX_SCORE * num / scale;
	232	}
	233
	234	void diffcore_rename(int detect_rename, int minimum_score)
427dcb4b	235	{
38c6f780	236	struct diff_queue_struct *q = &diff_queued_diff;
25d5ea41	237	struct diff_queue_struct renq, outq;
427dcb4b	238	struct diff_score *mx;
25d5ea41 JH	239	int i, j;
25d5ea41 JH	240	int num_create, num_src, dst_cnt;
427dcb4b	241
26dee0ad JH	242	if (!minimum_score)
26dee0ad JH	243	minimum_score = DEFAULT_MINIMUM_SCORE;
25d5ea41 JH	244	renq.queue = NULL;
25d5ea41 JH	245	renq.nr = renq.alloc = 0;
427dcb4b	246
427dcb4b	247	for (i = 0; i < q->nr; i++) {
52e95789	248	struct diff_filepair *p = q->queue[i];
81e50eab JH	249	if (!DIFF_FILE_VALID(p->one))
81e50eab JH	250	if (!DIFF_FILE_VALID(p->two))
60896c7b	251	continue; /* unmerged */
427dcb4b	252	else
25d5ea41	253	locate_rename_dst(p->two, 1);
81e50eab	254	else if (!DIFF_FILE_VALID(p->two))
15d061b4 JH	255	register_rename_src(p->one, 0);
	256	else if (detect_rename == DIFF_DETECT_COPY)
	257	register_rename_src(p->one, 1);
427dcb4b	258	}
25d5ea41	259	if (rename_dst_nr == 0)
427dcb4b JH	260	goto cleanup; /* nothing to do */
	261
	262	/* We really want to cull the candidates list early
	263	* with cheap tests in order to avoid doing deltas.
427dcb4b	264	*/
25d5ea41 JH	265	for (i = 0; i < rename_dst_nr; i++) {
	266	struct diff_filespec *two = rename_dst[i].two;
	267	for (j = 0; j < rename_src_nr; j++) {
	268	struct diff_filespec *one = rename_src[j].one;
	269	if (!is_exact_match(one, two))
	270	continue;
	271	record_rename_pair(&renq, i, j, MAX_SCORE);
	272	break; /* we are done with this entry */
427dcb4b JH	273	}
427dcb4b JH	274	}
25d5ea41	275	diff_debug_queue("done detecting exact", &renq);
427dcb4b JH	276
	277	/* Have we run out the created file pool? If so we can avoid
	278	* doing the delta matrix altogether.
	279	*/
25d5ea41	280	if (renq.nr == rename_dst_nr)
15d061b4	281	goto cleanup;
427dcb4b	282
25d5ea41 JH	283	num_create = (rename_dst_nr - renq.nr);
25d5ea41 JH	284	num_src = rename_src_nr;
427dcb4b	285	mx = xmalloc(sizeof(mx) num_create * num_src);
25d5ea41	286	for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b	287	int base = dst_cnt * num_src;
25d5ea41 JH	288	struct diff_filespec *two = rename_dst[i].two;
25d5ea41 JH	289	if (rename_dst[i].pair)
427dcb4b	290	continue; /* dealt with exact match already. */
25d5ea41 JH	291	for (j = 0; j < rename_src_nr; j++) {
	292	struct diff_filespec *one = rename_src[j].one;
	293	struct diff_score *m = &mx[base+j];
	294	m->src = j;
	295	m->dst = i;
	296	m->score = estimate_similarity(one, two,
	297	minimum_score);
427dcb4b JH	298	}
	299	dst_cnt++;
	300	}
	301	/* cost matrix sorted by most to least similar pair */
	302	qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
	303	for (i = 0; i < num_create * num_src; i++) {
25d5ea41 JH	304	struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
	305	if (dst->pair)
	306	continue; /* already done, either exact or fuzzy. */
427dcb4b	307	if (mx[i].score < minimum_score)
15d061b4	308	break; /* there is no more usable pair. */
25d5ea41	309	record_rename_pair(&renq, mx[i].dst, mx[i].src, mx[i].score);
427dcb4b JH	310	}
427dcb4b JH	311	free(mx);
25d5ea41	312	diff_debug_queue("done detecting fuzzy", &renq);
427dcb4b	313
15d061b4	314	cleanup:
427dcb4b	315	/* At this point, we have found some renames and copies and they
25d5ea41	316	* are kept in renq. The original list is still in *q.
427dcb4b	317	*/
25d5ea41 JH	318	outq.queue = NULL;
25d5ea41 JH	319	outq.nr = outq.alloc = 0;
427dcb4b	320	for (i = 0; i < q->nr; i++) {
25d5ea41	321	struct diff_filepair *p = q->queue[i];
25d5ea41 JH	322	struct diff_rename_dst *dst = locate_rename_dst(p->two, 0);
	323	struct diff_filepair *pair_to_free = NULL;
	324
	325	if (dst) {
	326	/* creation */
	327	if (dst->pair) {
15d061b4 JH	328	/* renq has rename/copy to produce
	329	* this file already, so we do not
	330	* emit the creation record in the
	331	* output.
25d5ea41 JH	332	*/
	333	diff_q(&outq, dst->pair);
	334	pair_to_free = p;
	335	}
	336	else
	337	/* no matching rename/copy source, so record
	338	* this as a creation.
	339	*/
	340	diff_q(&outq, p);
427dcb4b	341	}
25d5ea41	342	else if (!diff_unmodified_pair(p))
15d061b4	343	/* all the usual ones need to be kept */
25d5ea41	344	diff_q(&outq, p);
15d061b4 JH	345	else
	346	/* no need to keep unmodified pairs */
	347	pair_to_free = p;
	348
226406f6 JH	349	if (pair_to_free)
226406f6 JH	350	diff_free_filepair(pair_to_free);
427dcb4b	351	}
25d5ea41	352	diff_debug_queue("done copying original", &outq);
427dcb4b	353
25d5ea41 JH	354	free(renq.queue);
	355	free(q->queue);
	356	*q = outq;
	357	diff_debug_queue("done collapsing", q);
427dcb4b	358
25d5ea41 JH	359	free(rename_dst);
	360	rename_dst = NULL;
	361	rename_dst_nr = rename_dst_alloc = 0;
	362	free(rename_src);
	363	rename_src = NULL;
	364	rename_src_nr = rename_src_alloc = 0;
427dcb4b JH	365	return;
427dcb4b JH	366	}