[thirdparty/git.git] / range-diff.c

#include "cache.h"
#include "range-diff.h"
#include "string-list.h"
#include "run-command.h"
#include "argv-array.h"
#include "hashmap.h"
#include "xdiff-interface.h"
#include "linear-assignment.h"
#include "diffcore.h"
#include "commit.h"
#include "pretty.h"

struct patch_util {
	/* For the search for an exact match */
	struct hashmap_entry e;
	const char *diff, *patch;

	int i, shown;
	int diffsize;
	size_t diff_offset;
	/* the index of the matching item in the other branch, or -1 */
	int matching;
	struct object_id oid;
};

/*
 * Reads the patches into a string list, with the `util` field being populated
 * as struct object_id (will need to be free()d).
 */
static int read_patches(const char *range, struct string_list *list)
{
	struct child_process cp = CHILD_PROCESS_INIT;
	FILE *in;
	struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
	struct patch_util *util = NULL;
	int in_header = 1;

	argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
			"--reverse", "--date-order", "--decorate=no",
			"--no-abbrev-commit", range,
			NULL);
	cp.out = -1;
	cp.no_stdin = 1;
	cp.git_cmd = 1;

	if (start_command(&cp))
		return error_errno(_("could not start `log`"));
	in = fdopen(cp.out, "r");
	if (!in) {
		error_errno(_("could not read `log` output"));
		finish_command(&cp);
		return -1;
	}

	while (strbuf_getline(&line, in) != EOF) {
		const char *p;

		if (skip_prefix(line.buf, "commit ", &p)) {
			if (util) {
				string_list_append(list, buf.buf)->util = util;
				strbuf_reset(&buf);
			}
			util = xcalloc(sizeof(*util), 1);
			if (get_oid(p, &util->oid)) {
				error(_("could not parse commit '%s'"), p);
				free(util);
				string_list_clear(list, 1);
				strbuf_release(&buf);
				strbuf_release(&line);
				fclose(in);
				finish_command(&cp);
				return -1;
			}
			util->matching = -1;
			in_header = 1;
			continue;
		}

		if (starts_with(line.buf, "diff --git")) {
			in_header = 0;
			strbuf_addch(&buf, '\n');
			if (!util->diff_offset)
				util->diff_offset = buf.len;
			strbuf_addbuf(&buf, &line);
		} else if (in_header) {
			if (starts_with(line.buf, "Author: ")) {
				strbuf_addbuf(&buf, &line);
				strbuf_addstr(&buf, "\n\n");
			} else if (starts_with(line.buf, "    ")) {
				strbuf_rtrim(&line);
				strbuf_addbuf(&buf, &line);
				strbuf_addch(&buf, '\n');
			}
			continue;
		} else if (starts_with(line.buf, "@@ "))
			strbuf_addstr(&buf, "@@");
		else if (!line.buf[0] || starts_with(line.buf, "index "))
			/*
			 * A completely blank (not ' \n', which is context)
			 * line is not valid in a diff.  We skip it
			 * silently, because this neatly handles the blank
			 * separator line between commits in git-log
			 * output.
			 *
			 * We also want to ignore the diff's `index` lines
			 * because they contain exact blob hashes in which
			 * we are not interested.
			 */
			continue;
		else
			strbuf_addbuf(&buf, &line);

		strbuf_addch(&buf, '\n');
		util->diffsize++;
	}
	fclose(in);
	strbuf_release(&line);

	if (util)
		string_list_append(list, buf.buf)->util = util;
	strbuf_release(&buf);

	if (finish_command(&cp))
		return -1;

	return 0;
}

static int patch_util_cmp(const void *dummy, const struct patch_util *a,
		     const struct patch_util *b, const char *keydata)
{
	return strcmp(a->diff, keydata ? keydata : b->diff);
}

static void find_exact_matches(struct string_list *a, struct string_list *b)
{
	struct hashmap map;
	int i;

	hashmap_init(&map, (hashmap_cmp_fn)patch_util_cmp, NULL, 0);

	/* First, add the patches of a to a hash map */
	for (i = 0; i < a->nr; i++) {
		struct patch_util *util = a->items[i].util;

		util->i = i;
		util->patch = a->items[i].string;
		util->diff = util->patch + util->diff_offset;
		hashmap_entry_init(util, strhash(util->diff));
		hashmap_add(&map, util);
	}

	/* Now try to find exact matches in b */
	for (i = 0; i < b->nr; i++) {
		struct patch_util *util = b->items[i].util, *other;

		util->i = i;
		util->patch = b->items[i].string;
		util->diff = util->patch + util->diff_offset;
		hashmap_entry_init(util, strhash(util->diff));
		other = hashmap_remove(&map, util, NULL);
		if (other) {
			if (other->matching >= 0)
				BUG("already assigned!");

			other->matching = i;
			util->matching = other->i;
		}
	}

	hashmap_free(&map, 0);
}

static void diffsize_consume(void *data, char *line, unsigned long len)
{
	(*(int *)data)++;
}

static int diffsize(const char *a, const char *b)
{
	xpparam_t pp = { 0 };
	xdemitconf_t cfg = { 0 };
	mmfile_t mf1, mf2;
	int count = 0;

	mf1.ptr = (char *)a;
	mf1.size = strlen(a);
	mf2.ptr = (char *)b;
	mf2.size = strlen(b);

	cfg.ctxlen = 3;
	if (!xdi_diff_outf(&mf1, &mf2, diffsize_consume, &count, &pp, &cfg))
		return count;

	error(_("failed to generate diff"));
	return COST_MAX;
}

static void get_correspondences(struct string_list *a, struct string_list *b,
				int creation_factor)
{
	int n = a->nr + b->nr;
	int *cost, c, *a2b, *b2a;
	int i, j;

	ALLOC_ARRAY(cost, st_mult(n, n));
	ALLOC_ARRAY(a2b, n);
	ALLOC_ARRAY(b2a, n);

	for (i = 0; i < a->nr; i++) {
		struct patch_util *a_util = a->items[i].util;

		for (j = 0; j < b->nr; j++) {
			struct patch_util *b_util = b->items[j].util;

			if (a_util->matching == j)
				c = 0;
			else if (a_util->matching < 0 && b_util->matching < 0)
				c = diffsize(a_util->diff, b_util->diff);
			else
				c = COST_MAX;
			cost[i + n * j] = c;
		}

		c = a_util->matching < 0 ?
			a_util->diffsize * creation_factor / 100 : COST_MAX;
		for (j = b->nr; j < n; j++)
			cost[i + n * j] = c;
	}

	for (j = 0; j < b->nr; j++) {
		struct patch_util *util = b->items[j].util;

		c = util->matching < 0 ?
			util->diffsize * creation_factor / 100 : COST_MAX;
		for (i = a->nr; i < n; i++)
			cost[i + n * j] = c;
	}

	for (i = a->nr; i < n; i++)
		for (j = b->nr; j < n; j++)
			cost[i + n * j] = 0;

	compute_assignment(n, n, cost, a2b, b2a);

	for (i = 0; i < a->nr; i++)
		if (a2b[i] >= 0 && a2b[i] < b->nr) {
			struct patch_util *a_util = a->items[i].util;
			struct patch_util *b_util = b->items[a2b[i]].util;

			a_util->matching = a2b[i];
			b_util->matching = i;
		}

	free(cost);
	free(a2b);
	free(b2a);
}

static void output_pair_header(struct strbuf *buf,
			       struct strbuf *dashes,
			       struct patch_util *a_util,
			       struct patch_util *b_util)
{
	struct object_id *oid = a_util ? &a_util->oid : &b_util->oid;
	struct commit *commit;

	if (!dashes->len)
		strbuf_addchars(dashes, '-',
				strlen(find_unique_abbrev(oid,
							  DEFAULT_ABBREV)));

	strbuf_reset(buf);
	if (!a_util)
		strbuf_addf(buf, "-:  %s ", dashes->buf);
	else
		strbuf_addf(buf, "%d:  %s ", a_util->i + 1,
			    find_unique_abbrev(&a_util->oid, DEFAULT_ABBREV));

	if (!a_util)
		strbuf_addch(buf, '>');
	else if (!b_util)
		strbuf_addch(buf, '<');
	else if (strcmp(a_util->patch, b_util->patch))
		strbuf_addch(buf, '!');
	else
		strbuf_addch(buf, '=');

	if (!b_util)
		strbuf_addf(buf, " -:  %s", dashes->buf);
	else
		strbuf_addf(buf, " %d:  %s", b_util->i + 1,
			    find_unique_abbrev(&b_util->oid, DEFAULT_ABBREV));

	commit = lookup_commit_reference(the_repository, oid);
	if (commit) {
		strbuf_addch(buf, ' ');
		pp_commit_easy(CMIT_FMT_ONELINE, commit, buf);
	}
	strbuf_addch(buf, '\n');

	fwrite(buf->buf, buf->len, 1, stdout);
}

static struct diff_filespec *get_filespec(const char *name, const char *p)
{
	struct diff_filespec *spec = alloc_filespec(name);

	fill_filespec(spec, &null_oid, 0, 0644);
	spec->data = (char *)p;
	spec->size = strlen(p);
	spec->should_munmap = 0;
	spec->is_stdin = 1;

	return spec;
}

static void patch_diff(const char *a, const char *b,
			      struct diff_options *diffopt)
{
	diff_queue(&diff_queued_diff,
		   get_filespec("a", a), get_filespec("b", b));

	diffcore_std(diffopt);
	diff_flush(diffopt);
}

static void output(struct string_list *a, struct string_list *b,
		   struct diff_options *diffopt)
{
	struct strbuf buf = STRBUF_INIT, dashes = STRBUF_INIT;
	int i = 0, j = 0;

	/*
	 * We assume the user is really more interested in the second argument
	 * ("newer" version). To that end, we print the output in the order of
	 * the RHS (the `b` parameter). To put the LHS (the `a` parameter)
	 * commits that are no longer in the RHS into a good place, we place
	 * them once we have shown all of their predecessors in the LHS.
	 */

	while (i < a->nr || j < b->nr) {
		struct patch_util *a_util, *b_util;
		a_util = i < a->nr ? a->items[i].util : NULL;
		b_util = j < b->nr ? b->items[j].util : NULL;

		/* Skip all the already-shown commits from the LHS. */
		while (i < a->nr && a_util->shown)
			a_util = ++i < a->nr ? a->items[i].util : NULL;

		/* Show unmatched LHS commit whose predecessors were shown. */
		if (i < a->nr && a_util->matching < 0) {
			output_pair_header(&buf, &dashes, a_util, NULL);
			i++;
			continue;
		}

		/* Show unmatched RHS commits. */
		while (j < b->nr && b_util->matching < 0) {
			output_pair_header(&buf, &dashes, NULL, b_util);
			b_util = ++j < b->nr ? b->items[j].util : NULL;
		}

		/* Show matching LHS/RHS pair. */
		if (j < b->nr) {
			a_util = a->items[b_util->matching].util;
			output_pair_header(&buf, &dashes, a_util, b_util);
			if (!(diffopt->output_format & DIFF_FORMAT_NO_OUTPUT))
				patch_diff(a->items[b_util->matching].string,
					   b->items[j].string, diffopt);
			a_util->shown = 1;
			j++;
		}
	}
	strbuf_release(&buf);
	strbuf_release(&dashes);
}

int show_range_diff(const char *range1, const char *range2,
		    int creation_factor, struct diff_options *diffopt)
{
	int res = 0;

	struct string_list branch1 = STRING_LIST_INIT_DUP;
	struct string_list branch2 = STRING_LIST_INIT_DUP;

	if (read_patches(range1, &branch1))
		res = error(_("could not parse log for '%s'"), range1);
	if (!res && read_patches(range2, &branch2))
		res = error(_("could not parse log for '%s'"), range2);

	if (!res) {
		find_exact_matches(&branch1, &branch2);
		get_correspondences(&branch1, &branch2, creation_factor);
		output(&branch1, &branch2, diffopt);
	}

	string_list_clear(&branch1, 1);
	string_list_clear(&branch2, 1);

	return res;
}
Commit	Line	Data
d9c66f0b JS	1	#include "cache.h"
	2	#include "range-diff.h"
	3	#include "string-list.h"
	4	#include "run-command.h"
	5	#include "argv-array.h"
	6	#include "hashmap.h"
	7	#include "xdiff-interface.h"
	8	#include "linear-assignment.h"
c8c5e43a	9	#include "diffcore.h"
eb0be38c JS	10	#include "commit.h"
eb0be38c JS	11	#include "pretty.h"
d9c66f0b JS	12
	13	struct patch_util {
	14	/* For the search for an exact match */
	15	struct hashmap_entry e;
	16	const char diff, patch;
	17
9dc46e02	18	int i, shown;
d9c66f0b JS	19	int diffsize;
	20	size_t diff_offset;
	21	/* the index of the matching item in the other branch, or -1 */
	22	int matching;
	23	struct object_id oid;
	24	};
	25
	26	/*
	27	* Reads the patches into a string list, with the `util` field being populated
	28	* as struct object_id (will need to be free()d).
	29	*/
	30	static int read_patches(const char range, struct string_list list)
	31	{
	32	struct child_process cp = CHILD_PROCESS_INIT;
	33	FILE *in;
	34	struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
	35	struct patch_util *util = NULL;
	36	int in_header = 1;
	37
	38	argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
	39	"--reverse", "--date-order", "--decorate=no",
	40	"--no-abbrev-commit", range,
	41	NULL);
	42	cp.out = -1;
	43	cp.no_stdin = 1;
	44	cp.git_cmd = 1;
	45
	46	if (start_command(&cp))
	47	return error_errno(_("could not start `log`"));
	48	in = fdopen(cp.out, "r");
	49	if (!in) {
	50	error_errno(_("could not read `log` output"));
	51	finish_command(&cp);
	52	return -1;
	53	}
	54
	55	while (strbuf_getline(&line, in) != EOF) {
	56	const char *p;
	57
	58	if (skip_prefix(line.buf, "commit ", &p)) {
	59	if (util) {
	60	string_list_append(list, buf.buf)->util = util;
	61	strbuf_reset(&buf);
	62	}
	63	util = xcalloc(sizeof(*util), 1);
	64	if (get_oid(p, &util->oid)) {
	65	error(_("could not parse commit '%s'"), p);
	66	free(util);
	67	string_list_clear(list, 1);
	68	strbuf_release(&buf);
	69	strbuf_release(&line);
	70	fclose(in);
	71	finish_command(&cp);
	72	return -1;
	73	}
	74	util->matching = -1;
	75	in_header = 1;
	76	continue;
	77	}
	78
	79	if (starts_with(line.buf, "diff --git")) {
	80	in_header = 0;
	81	strbuf_addch(&buf, '\n');
	82	if (!util->diff_offset)
83	util->diff_offset = buf.len;
84	strbuf_addbuf(&buf, &line);
85	} else if (in_header) {
86	if (starts_with(line.buf, "Author: ")) {
87	strbuf_addbuf(&buf, &line);
88	strbuf_addstr(&buf, "\n\n");
89	} else if (starts_with(line.buf, " ")) {
a142f978	90	strbuf_rtrim(&line);
d9c66f0b JS	91	strbuf_addbuf(&buf, &line);
	92	strbuf_addch(&buf, '\n');
	93	}
	94	continue;
	95	} else if (starts_with(line.buf, "@@ "))
	96	strbuf_addstr(&buf, "@@");
	97	else if (!line.buf[0] \|\| starts_with(line.buf, "index "))
	98	/*
	99	* A completely blank (not ' \n', which is context)
	100	* line is not valid in a diff. We skip it
	101	* silently, because this neatly handles the blank
	102	* separator line between commits in git-log
	103	* output.
	104	*
	105	* We also want to ignore the diff's `index` lines
	106	* because they contain exact blob hashes in which
	107	* we are not interested.
	108	*/
	109	continue;
	110	else
	111	strbuf_addbuf(&buf, &line);
	112
	113	strbuf_addch(&buf, '\n');
	114	util->diffsize++;
	115	}
	116	fclose(in);
	117	strbuf_release(&line);
	118
	119	if (util)
	120	string_list_append(list, buf.buf)->util = util;
	121	strbuf_release(&buf);
	122
	123	if (finish_command(&cp))
	124	return -1;
	125
	126	return 0;
	127	}
	128
	129	static int patch_util_cmp(const void dummy, const struct patch_util a,
	130	const struct patch_util b, const char keydata)
	131	{
	132	return strcmp(a->diff, keydata ? keydata : b->diff);
	133	}
	134
	135	static void find_exact_matches(struct string_list a, struct string_list b)
	136	{
	137	struct hashmap map;
	138	int i;
	139
	140	hashmap_init(&map, (hashmap_cmp_fn)patch_util_cmp, NULL, 0);
	141
	142	/* First, add the patches of a to a hash map */
	143	for (i = 0; i < a->nr; i++) {
	144	struct patch_util *util = a->items[i].util;
	145
	146	util->i = i;
	147	util->patch = a->items[i].string;
	148	util->diff = util->patch + util->diff_offset;
	149	hashmap_entry_init(util, strhash(util->diff));
	150	hashmap_add(&map, util);
	151	}
	152
	153	/* Now try to find exact matches in b */
	154	for (i = 0; i < b->nr; i++) {
155	struct patch_util util = b->items[i].util, other;
156
157	util->i = i;
158	util->patch = b->items[i].string;
159	util->diff = util->patch + util->diff_offset;
160	hashmap_entry_init(util, strhash(util->diff));
161	other = hashmap_remove(&map, util, NULL);
162	if (other) {
163	if (other->matching >= 0)
164	BUG("already assigned!");
165
166	other->matching = i;
167	util->matching = other->i;
168	}
169	}
170
171	hashmap_free(&map, 0);
172	}
173
174	static void diffsize_consume(void data, char line, unsigned long len)
175	{
176	((int )data)++;
177	}
178
179	static int diffsize(const char a, const char b)
180	{
181	xpparam_t pp = { 0 };
182	xdemitconf_t cfg = { 0 };
183	mmfile_t mf1, mf2;
184	int count = 0;
185
186	mf1.ptr = (char *)a;
187	mf1.size = strlen(a);
188	mf2.ptr = (char *)b;
189	mf2.size = strlen(b);
190
191	cfg.ctxlen = 3;
192	if (!xdi_diff_outf(&mf1, &mf2, diffsize_consume, &count, &pp, &cfg))
193	return count;
194
195	error(_("failed to generate diff"));
196	return COST_MAX;
197	}
198
199	static void get_correspondences(struct string_list a, struct string_list b,
200	int creation_factor)
201	{
202	int n = a->nr + b->nr;
203	int cost, c, a2b, *b2a;
204	int i, j;
205
206	ALLOC_ARRAY(cost, st_mult(n, n));
207	ALLOC_ARRAY(a2b, n);
208	ALLOC_ARRAY(b2a, n);
209
210	for (i = 0; i < a->nr; i++) {
211	struct patch_util *a_util = a->items[i].util;
212
213	for (j = 0; j < b->nr; j++) {
214	struct patch_util *b_util = b->items[j].util;
215
216	if (a_util->matching == j)
217	c = 0;
218	else if (a_util->matching < 0 && b_util->matching < 0)
219	c = diffsize(a_util->diff, b_util->diff);
220	else
221	c = COST_MAX;
222	cost[i + n * j] = c;
223	}
224
225	c = a_util->matching < 0 ?
226	a_util->diffsize * creation_factor / 100 : COST_MAX;
227	for (j = b->nr; j < n; j++)
228	cost[i + n * j] = c;
229	}
230
231	for (j = 0; j < b->nr; j++) {
232	struct patch_util *util = b->items[j].util;
233
234	c = util->matching < 0 ?
235	util->diffsize * creation_factor / 100 : COST_MAX;
236	for (i = a->nr; i < n; i++)
237	cost[i + n * j] = c;
238	}
239
240	for (i = a->nr; i < n; i++)
241	for (j = b->nr; j < n; j++)
242	cost[i + n * j] = 0;
243
244	compute_assignment(n, n, cost, a2b, b2a);
245
246	for (i = 0; i < a->nr; i++)
247	if (a2b[i] >= 0 && a2b[i] < b->nr) {
248	struct patch_util *a_util = a->items[i].util;
249	struct patch_util *b_util = b->items[a2b[i]].util;
250
251	a_util->matching = a2b[i];
252	b_util->matching = i;
253	}
254
255	free(cost);
256	free(a2b);
257	free(b2a);
258	}
259
eb0be38c JS	260	static void output_pair_header(struct strbuf *buf,
	261	struct strbuf *dashes,
	262	struct patch_util *a_util,
	263	struct patch_util *b_util)
d9c66f0b	264	{
eb0be38c JS	265	struct object_id *oid = a_util ? &a_util->oid : &b_util->oid;
	266	struct commit *commit;
	267
	268	if (!dashes->len)
	269	strbuf_addchars(dashes, '-',
	270	strlen(find_unique_abbrev(oid,
	271	DEFAULT_ABBREV)));
	272
	273	strbuf_reset(buf);
	274	if (!a_util)
	275	strbuf_addf(buf, "-: %s ", dashes->buf);
	276	else
	277	strbuf_addf(buf, "%d: %s ", a_util->i + 1,
	278	find_unique_abbrev(&a_util->oid, DEFAULT_ABBREV));
	279
	280	if (!a_util)
	281	strbuf_addch(buf, '>');
	282	else if (!b_util)
	283	strbuf_addch(buf, '<');
	284	else if (strcmp(a_util->patch, b_util->patch))
	285	strbuf_addch(buf, '!');
	286	else
	287	strbuf_addch(buf, '=');
	288
	289	if (!b_util)
	290	strbuf_addf(buf, " -: %s", dashes->buf);
	291	else
	292	strbuf_addf(buf, " %d: %s", b_util->i + 1,
	293	find_unique_abbrev(&b_util->oid, DEFAULT_ABBREV));
	294
	295	commit = lookup_commit_reference(the_repository, oid);
	296	if (commit) {
	297	strbuf_addch(buf, ' ');
	298	pp_commit_easy(CMIT_FMT_ONELINE, commit, buf);
	299	}
	300	strbuf_addch(buf, '\n');
	301
	302	fwrite(buf->buf, buf->len, 1, stdout);
d9c66f0b JS	303	}
d9c66f0b JS	304
c8c5e43a JS	305	static struct diff_filespec get_filespec(const char name, const char *p)
	306	{
	307	struct diff_filespec *spec = alloc_filespec(name);
	308
	309	fill_filespec(spec, &null_oid, 0, 0644);
	310	spec->data = (char *)p;
	311	spec->size = strlen(p);
	312	spec->should_munmap = 0;
	313	spec->is_stdin = 1;
	314
	315	return spec;
	316	}
	317
	318	static void patch_diff(const char a, const char b,
	319	struct diff_options *diffopt)
	320	{
	321	diff_queue(&diff_queued_diff,
	322	get_filespec("a", a), get_filespec("b", b));
	323
	324	diffcore_std(diffopt);
	325	diff_flush(diffopt);
	326	}
	327
	328	static void output(struct string_list a, struct string_list b,
	329	struct diff_options *diffopt)
d9c66f0b	330	{
eb0be38c	331	struct strbuf buf = STRBUF_INIT, dashes = STRBUF_INIT;
9dc46e02 JS	332	int i = 0, j = 0;
	333
	334	/*
	335	* We assume the user is really more interested in the second argument
	336	* ("newer" version). To that end, we print the output in the order of
	337	* the RHS (the `b` parameter). To put the LHS (the `a` parameter)
	338	* commits that are no longer in the RHS into a good place, we place
	339	* them once we have shown all of their predecessors in the LHS.
	340	*/
	341
	342	while (i < a->nr \|\| j < b->nr) {
	343	struct patch_util a_util, b_util;
	344	a_util = i < a->nr ? a->items[i].util : NULL;
	345	b_util = j < b->nr ? b->items[j].util : NULL;
	346
	347	/* Skip all the already-shown commits from the LHS. */
	348	while (i < a->nr && a_util->shown)
	349	a_util = ++i < a->nr ? a->items[i].util : NULL;
	350
	351	/* Show unmatched LHS commit whose predecessors were shown. */
	352	if (i < a->nr && a_util->matching < 0) {
eb0be38c	353	output_pair_header(&buf, &dashes, a_util, NULL);
9dc46e02 JS	354	i++;
	355	continue;
	356	}
d9c66f0b	357
9dc46e02 JS	358	/* Show unmatched RHS commits. */
9dc46e02 JS	359	while (j < b->nr && b_util->matching < 0) {
eb0be38c	360	output_pair_header(&buf, &dashes, NULL, b_util);
9dc46e02	361	b_util = ++j < b->nr ? b->items[j].util : NULL;
d9c66f0b	362	}
d9c66f0b	363
9dc46e02 JS	364	/* Show matching LHS/RHS pair. */
	365	if (j < b->nr) {
	366	a_util = a->items[b_util->matching].util;
eb0be38c	367	output_pair_header(&buf, &dashes, a_util, b_util);
c8c5e43a JS	368	if (!(diffopt->output_format & DIFF_FORMAT_NO_OUTPUT))
	369	patch_diff(a->items[b_util->matching].string,
	370	b->items[j].string, diffopt);
9dc46e02 JS	371	a_util->shown = 1;
	372	j++;
	373	}
d9c66f0b	374	}
eb0be38c JS	375	strbuf_release(&buf);
eb0be38c JS	376	strbuf_release(&dashes);
d9c66f0b JS	377	}
	378
	379	int show_range_diff(const char range1, const char range2,
c8c5e43a	380	int creation_factor, struct diff_options *diffopt)
d9c66f0b JS	381	{
	382	int res = 0;
	383
	384	struct string_list branch1 = STRING_LIST_INIT_DUP;
	385	struct string_list branch2 = STRING_LIST_INIT_DUP;
	386
	387	if (read_patches(range1, &branch1))
	388	res = error(_("could not parse log for '%s'"), range1);
	389	if (!res && read_patches(range2, &branch2))
	390	res = error(_("could not parse log for '%s'"), range2);
	391
	392	if (!res) {
	393	find_exact_matches(&branch1, &branch2);
	394	get_correspondences(&branch1, &branch2, creation_factor);
c8c5e43a	395	output(&branch1, &branch2, diffopt);
d9c66f0b JS	396	}
	397
	398	string_list_clear(&branch1, 1);
	399	string_list_clear(&branch2, 1);
	400
	401	return res;
	402	}