[thirdparty/git.git] / rerere.c

#include "cache.h"
#include "string-list.h"
#include "rerere.h"
#include "xdiff/xdiff.h"
#include "xdiff-interface.h"

/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
static int rerere_enabled = -1;

/* automatically update cleanly resolved paths to the index */
static int rerere_autoupdate;

static char *merge_rr_path;

static const char *rr_path(const char *name, const char *file)
{
	return git_path("rr-cache/%s/%s", name, file);
}

static int has_resolution(const char *name)
{
	struct stat st;
	return !stat(rr_path(name, "postimage"), &st);
}

static void read_rr(struct string_list *rr)
{
	unsigned char sha1[20];
	char buf[PATH_MAX];
	FILE *in = fopen(merge_rr_path, "r");
	if (!in)
		return;
	while (fread(buf, 40, 1, in) == 1) {
		int i;
		char *name;
		if (get_sha1_hex(buf, sha1))
			die("corrupt MERGE_RR");
		buf[40] = '\0';
		name = xstrdup(buf);
		if (fgetc(in) != '\t')
			die("corrupt MERGE_RR");
		for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
			; /* do nothing */
		if (i == sizeof(buf))
			die("filename too long");
		string_list_insert(buf, rr)->util = name;
	}
	fclose(in);
}

static struct lock_file write_lock;

static int write_rr(struct string_list *rr, int out_fd)
{
	int i;
	for (i = 0; i < rr->nr; i++) {
		const char *path;
		int length;
		if (!rr->items[i].util)
			continue;
		path = rr->items[i].string;
		length = strlen(path) + 1;
		if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
		    write_in_full(out_fd, "\t", 1) != 1 ||
		    write_in_full(out_fd, path, length) != length)
			die("unable to write rerere record");
	}
	if (commit_lock_file(&write_lock) != 0)
		die("unable to write rerere record");
	return 0;
}

static int handle_file(const char *path,
	 unsigned char *sha1, const char *output)
{
	SHA_CTX ctx;
	char buf[1024];
	int hunk_no = 0;
	enum {
		RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2,
	} hunk = RR_CONTEXT;
	struct strbuf one, two;
	FILE *f = fopen(path, "r");
	FILE *out = NULL;

	if (!f)
		return error("Could not open %s", path);

	if (output) {
		out = fopen(output, "w");
		if (!out) {
			fclose(f);
			return error("Could not write %s", output);
		}
	}

	if (sha1)
		SHA1_Init(&ctx);

	strbuf_init(&one, 0);
	strbuf_init(&two,  0);
	while (fgets(buf, sizeof(buf), f)) {
		if (!prefixcmp(buf, "<<<<<<< ")) {
			if (hunk != RR_CONTEXT)
				goto bad;
			hunk = RR_SIDE_1;
		} else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
			if (hunk != RR_SIDE_1)
				goto bad;
			hunk = RR_SIDE_2;
		} else if (!prefixcmp(buf, ">>>>>>> ")) {
			if (hunk != RR_SIDE_2)
				goto bad;
			if (strbuf_cmp(&one, &two) > 0)
				strbuf_swap(&one, &two);
			hunk_no++;
			hunk = RR_CONTEXT;
			if (out) {
				fputs("<<<<<<<\n", out);
				fwrite(one.buf, one.len, 1, out);
				fputs("=======\n", out);
				fwrite(two.buf, two.len, 1, out);
				fputs(">>>>>>>\n", out);
			}
			if (sha1) {
				SHA1_Update(&ctx, one.buf ? one.buf : "",
					    one.len + 1);
				SHA1_Update(&ctx, two.buf ? two.buf : "",
					    two.len + 1);
			}
			strbuf_reset(&one);
			strbuf_reset(&two);
		} else if (hunk == RR_SIDE_1)
			strbuf_addstr(&one, buf);
		else if (hunk == RR_SIDE_2)
			strbuf_addstr(&two, buf);
		else if (out)
			fputs(buf, out);
		continue;
	bad:
		hunk = 99; /* force error exit */
		break;
	}
	strbuf_release(&one);
	strbuf_release(&two);

	fclose(f);
	if (out)
		fclose(out);
	if (sha1)
		SHA1_Final(sha1, &ctx);
	if (hunk != RR_CONTEXT) {
		if (output)
			unlink(output);
		return error("Could not parse conflict hunks in %s", path);
	}
	return hunk_no;
}

static int find_conflict(struct string_list *conflict)
{
	int i;
	if (read_cache() < 0)
		return error("Could not read index");
	for (i = 0; i+1 < active_nr; i++) {
		struct cache_entry *e2 = active_cache[i];
		struct cache_entry *e3 = active_cache[i+1];
		if (ce_stage(e2) == 2 &&
		    ce_stage(e3) == 3 &&
		    ce_same_name(e2, e3) &&
		    S_ISREG(e2->ce_mode) &&
		    S_ISREG(e3->ce_mode)) {
			string_list_insert((const char *)e2->name, conflict);
			i++; /* skip over both #2 and #3 */
		}
	}
	return 0;
}

static int merge(const char *name, const char *path)
{
	int ret;
	mmfile_t cur, base, other;
	mmbuffer_t result = {NULL, 0};
	xpparam_t xpp = {XDF_NEED_MINIMAL};

	if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
		return 1;

	if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
			read_mmfile(&base, rr_path(name, "preimage")) ||
			read_mmfile(&other, rr_path(name, "postimage")))
		return 1;
	ret = xdl_merge(&base, &cur, "", &other, "",
			&xpp, XDL_MERGE_ZEALOUS, &result);
	if (!ret) {
		FILE *f = fopen(path, "w");
		if (!f)
			return error("Could not write to %s", path);
		fwrite(result.ptr, result.size, 1, f);
		fclose(f);
	}

	free(cur.ptr);
	free(base.ptr);
	free(other.ptr);
	free(result.ptr);

	return ret;
}

static struct lock_file index_lock;

static int update_paths(struct string_list *update)
{
	int i;
	int fd = hold_locked_index(&index_lock, 0);
	int status = 0;

	if (fd < 0)
		return -1;

	for (i = 0; i < update->nr; i++) {
		struct string_list_item *item = &update->items[i];
		if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
			status = -1;
	}

	if (!status && active_cache_changed) {
		if (write_cache(fd, active_cache, active_nr) ||
		    commit_locked_index(&index_lock))
			die("Unable to write new index file");
	} else if (fd >= 0)
		rollback_lock_file(&index_lock);
	return status;
}

static int do_plain_rerere(struct string_list *rr, int fd)
{
	struct string_list conflict = { NULL, 0, 0, 1 };
	struct string_list update = { NULL, 0, 0, 1 };
	int i;

	find_conflict(&conflict);

	/*
	 * MERGE_RR records paths with conflicts immediately after merge
	 * failed.  Some of the conflicted paths might have been hand resolved
	 * in the working tree since then, but the initial run would catch all
	 * and register their preimages.
	 */

	for (i = 0; i < conflict.nr; i++) {
		const char *path = conflict.items[i].string;
		if (!string_list_has_string(rr, path)) {
			unsigned char sha1[20];
			char *hex;
			int ret;
			ret = handle_file(path, sha1, NULL);
			if (ret < 1)
				continue;
			hex = xstrdup(sha1_to_hex(sha1));
			string_list_insert(path, rr)->util = hex;
			if (mkdir(git_path("rr-cache/%s", hex), 0755))
				continue;;
			handle_file(path, NULL, rr_path(hex, "preimage"));
			fprintf(stderr, "Recorded preimage for '%s'\n", path);
		}
	}

	/*
	 * Now some of the paths that had conflicts earlier might have been
	 * hand resolved.  Others may be similar to a conflict already that
	 * was resolved before.
	 */

	for (i = 0; i < rr->nr; i++) {
		int ret;
		const char *path = rr->items[i].string;
		const char *name = (const char *)rr->items[i].util;

		if (has_resolution(name)) {
			if (!merge(name, path)) {
				if (rerere_autoupdate)
					string_list_insert(path, &update);
				fprintf(stderr,
					"%s '%s' using previous resolution.\n",
					rerere_autoupdate
					? "Staged" : "Resolved",
					path);
				goto mark_resolved;
			}
		}

		/* Let's see if we have resolved it. */
		ret = handle_file(path, NULL, NULL);
		if (ret)
			continue;

		fprintf(stderr, "Recorded resolution for '%s'.\n", path);
		copy_file(rr_path(name, "postimage"), path, 0666);
	mark_resolved:
		rr->items[i].util = NULL;
	}

	if (update.nr)
		update_paths(&update);

	return write_rr(rr, fd);
}

static int git_rerere_config(const char *var, const char *value, void *cb)
{
	if (!strcmp(var, "rerere.enabled"))
		rerere_enabled = git_config_bool(var, value);
	else if (!strcmp(var, "rerere.autoupdate"))
		rerere_autoupdate = git_config_bool(var, value);
	else
		return git_default_config(var, value, cb);
	return 0;
}

static int is_rerere_enabled(void)
{
	struct stat st;
	const char *rr_cache;
	int rr_cache_exists;

	if (!rerere_enabled)
		return 0;

	rr_cache = git_path("rr-cache");
	rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
	if (rerere_enabled < 0)
		return rr_cache_exists;

	if (!rr_cache_exists &&
	    (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
		die("Could not create directory %s", rr_cache);
	return 1;
}

int setup_rerere(struct string_list *merge_rr)
{
	int fd;

	git_config(git_rerere_config, NULL);
	if (!is_rerere_enabled())
		return -1;

	merge_rr_path = xstrdup(git_path("MERGE_RR"));
	fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
	read_rr(merge_rr);
	return fd;
}

int rerere(void)
{
	struct string_list merge_rr = { NULL, 0, 0, 1 };
	int fd;

	fd = setup_rerere(&merge_rr);
	if (fd < 0)
		return 0;
	return do_plain_rerere(&merge_rr, fd);
}
Commit	Line	Data
5b2fd956	1	#include "cache.h"
c455c87c	2	#include "string-list.h"
5b2fd956 SB	3	#include "rerere.h"
	4	#include "xdiff/xdiff.h"
	5	#include "xdiff-interface.h"
	6
	7	/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
	8	static int rerere_enabled = -1;
	9
	10	/* automatically update cleanly resolved paths to the index */
	11	static int rerere_autoupdate;
	12
	13	static char *merge_rr_path;
	14
	15	static const char rr_path(const char name, const char *file)
	16	{
	17	return git_path("rr-cache/%s/%s", name, file);
	18	}
	19
	20	static int has_resolution(const char *name)
	21	{
	22	struct stat st;
	23	return !stat(rr_path(name, "postimage"), &st);
	24	}
	25
c455c87c	26	static void read_rr(struct string_list *rr)
5b2fd956 SB	27	{
	28	unsigned char sha1[20];
	29	char buf[PATH_MAX];
	30	FILE *in = fopen(merge_rr_path, "r");
	31	if (!in)
	32	return;
	33	while (fread(buf, 40, 1, in) == 1) {
	34	int i;
	35	char *name;
	36	if (get_sha1_hex(buf, sha1))
	37	die("corrupt MERGE_RR");
	38	buf[40] = '\0';
	39	name = xstrdup(buf);
	40	if (fgetc(in) != '\t')
	41	die("corrupt MERGE_RR");
	42	for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
	43	; /* do nothing */
	44	if (i == sizeof(buf))
	45	die("filename too long");
c455c87c	46	string_list_insert(buf, rr)->util = name;
5b2fd956 SB	47	}
	48	fclose(in);
	49	}
	50
	51	static struct lock_file write_lock;
	52
c455c87c	53	static int write_rr(struct string_list *rr, int out_fd)
5b2fd956 SB	54	{
	55	int i;
	56	for (i = 0; i < rr->nr; i++) {
	57	const char *path;
	58	int length;
	59	if (!rr->items[i].util)
	60	continue;
c455c87c	61	path = rr->items[i].string;
5b2fd956 SB	62	length = strlen(path) + 1;
	63	if (write_in_full(out_fd, rr->items[i].util, 40) != 40 \|\|
	64	write_in_full(out_fd, "\t", 1) != 1 \|\|
	65	write_in_full(out_fd, path, length) != length)
	66	die("unable to write rerere record");
	67	}
	68	if (commit_lock_file(&write_lock) != 0)
	69	die("unable to write rerere record");
	70	return 0;
	71	}
	72
	73	static int handle_file(const char *path,
	74	unsigned char sha1, const char output)
	75	{
	76	SHA_CTX ctx;
	77	char buf[1024];
cc58d7df JH	78	int hunk_no = 0;
	79	enum {
	80	RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2,
	81	} hunk = RR_CONTEXT;
5b2fd956 SB	82	struct strbuf one, two;
	83	FILE *f = fopen(path, "r");
	84	FILE *out = NULL;
	85
	86	if (!f)
	87	return error("Could not open %s", path);
	88
	89	if (output) {
	90	out = fopen(output, "w");
	91	if (!out) {
	92	fclose(f);
	93	return error("Could not write %s", output);
	94	}
	95	}
	96
	97	if (sha1)
	98	SHA1_Init(&ctx);
	99
	100	strbuf_init(&one, 0);
	101	strbuf_init(&two, 0);
	102	while (fgets(buf, sizeof(buf), f)) {
	103	if (!prefixcmp(buf, "<<<<<<< ")) {
cc58d7df	104	if (hunk != RR_CONTEXT)
5b2fd956	105	goto bad;
cc58d7df	106	hunk = RR_SIDE_1;
5b2fd956	107	} else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
cc58d7df	108	if (hunk != RR_SIDE_1)
5b2fd956	109	goto bad;
cc58d7df	110	hunk = RR_SIDE_2;
5b2fd956	111	} else if (!prefixcmp(buf, ">>>>>>> ")) {
cc58d7df	112	if (hunk != RR_SIDE_2)
5b2fd956 SB	113	goto bad;
	114	if (strbuf_cmp(&one, &two) > 0)
	115	strbuf_swap(&one, &two);
	116	hunk_no++;
cc58d7df	117	hunk = RR_CONTEXT;
5b2fd956 SB	118	if (out) {
	119	fputs("<<<<<<<\n", out);
	120	fwrite(one.buf, one.len, 1, out);
	121	fputs("=======\n", out);
	122	fwrite(two.buf, two.len, 1, out);
	123	fputs(">>>>>>>\n", out);
	124	}
	125	if (sha1) {
	126	SHA1_Update(&ctx, one.buf ? one.buf : "",
	127	one.len + 1);
	128	SHA1_Update(&ctx, two.buf ? two.buf : "",
	129	two.len + 1);
	130	}
	131	strbuf_reset(&one);
	132	strbuf_reset(&two);
cc58d7df	133	} else if (hunk == RR_SIDE_1)
5b2fd956	134	strbuf_addstr(&one, buf);
cc58d7df	135	else if (hunk == RR_SIDE_2)
5b2fd956 SB	136	strbuf_addstr(&two, buf);
	137	else if (out)
	138	fputs(buf, out);
	139	continue;
	140	bad:
	141	hunk = 99; /* force error exit */
	142	break;
	143	}
	144	strbuf_release(&one);
	145	strbuf_release(&two);
	146
	147	fclose(f);
	148	if (out)
	149	fclose(out);
	150	if (sha1)
	151	SHA1_Final(sha1, &ctx);
cc58d7df	152	if (hunk != RR_CONTEXT) {
5b2fd956 SB	153	if (output)
	154	unlink(output);
	155	return error("Could not parse conflict hunks in %s", path);
	156	}
	157	return hunk_no;
	158	}
	159
c455c87c	160	static int find_conflict(struct string_list *conflict)
5b2fd956 SB	161	{
	162	int i;
	163	if (read_cache() < 0)
	164	return error("Could not read index");
	165	for (i = 0; i+1 < active_nr; i++) {
	166	struct cache_entry *e2 = active_cache[i];
	167	struct cache_entry *e3 = active_cache[i+1];
	168	if (ce_stage(e2) == 2 &&
	169	ce_stage(e3) == 3 &&
	170	ce_same_name(e2, e3) &&
	171	S_ISREG(e2->ce_mode) &&
	172	S_ISREG(e3->ce_mode)) {
c455c87c	173	string_list_insert((const char *)e2->name, conflict);
5b2fd956 SB	174	i++; /* skip over both #2 and #3 */
	175	}
	176	}
	177	return 0;
	178	}
	179
	180	static int merge(const char name, const char path)
	181	{
	182	int ret;
	183	mmfile_t cur, base, other;
	184	mmbuffer_t result = {NULL, 0};
	185	xpparam_t xpp = {XDF_NEED_MINIMAL};
	186
	187	if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
	188	return 1;
	189
	190	if (read_mmfile(&cur, rr_path(name, "thisimage")) \|\|
	191	read_mmfile(&base, rr_path(name, "preimage")) \|\|
	192	read_mmfile(&other, rr_path(name, "postimage")))
	193	return 1;
	194	ret = xdl_merge(&base, &cur, "", &other, "",
	195	&xpp, XDL_MERGE_ZEALOUS, &result);
	196	if (!ret) {
	197	FILE *f = fopen(path, "w");
	198	if (!f)
	199	return error("Could not write to %s", path);
	200	fwrite(result.ptr, result.size, 1, f);
	201	fclose(f);
	202	}
	203
	204	free(cur.ptr);
	205	free(base.ptr);
	206	free(other.ptr);
	207	free(result.ptr);
	208
	209	return ret;
	210	}
	211
	212	static struct lock_file index_lock;
	213
c455c87c	214	static int update_paths(struct string_list *update)
5b2fd956 SB	215	{
	216	int i;
	217	int fd = hold_locked_index(&index_lock, 0);
	218	int status = 0;
	219
	220	if (fd < 0)
	221	return -1;
	222
	223	for (i = 0; i < update->nr; i++) {
c455c87c JS	224	struct string_list_item *item = &update->items[i];
c455c87c JS	225	if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
5b2fd956 SB	226	status = -1;
	227	}
	228
	229	if (!status && active_cache_changed) {
	230	if (write_cache(fd, active_cache, active_nr) \|\|
	231	commit_locked_index(&index_lock))
	232	die("Unable to write new index file");
	233	} else if (fd >= 0)
	234	rollback_lock_file(&index_lock);
	235	return status;
	236	}
	237
c455c87c	238	static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956	239	{
c455c87c JS	240	struct string_list conflict = { NULL, 0, 0, 1 };
c455c87c JS	241	struct string_list update = { NULL, 0, 0, 1 };
5b2fd956 SB	242	int i;
	243
	244	find_conflict(&conflict);
	245
	246	/*
	247	* MERGE_RR records paths with conflicts immediately after merge
	248	* failed. Some of the conflicted paths might have been hand resolved
	249	* in the working tree since then, but the initial run would catch all
	250	* and register their preimages.
	251	*/
	252
	253	for (i = 0; i < conflict.nr; i++) {
c455c87c JS	254	const char *path = conflict.items[i].string;
c455c87c JS	255	if (!string_list_has_string(rr, path)) {
5b2fd956 SB	256	unsigned char sha1[20];
	257	char *hex;
	258	int ret;
	259	ret = handle_file(path, sha1, NULL);
	260	if (ret < 1)
	261	continue;
	262	hex = xstrdup(sha1_to_hex(sha1));
c455c87c	263	string_list_insert(path, rr)->util = hex;
5b2fd956 SB	264	if (mkdir(git_path("rr-cache/%s", hex), 0755))
	265	continue;;
	266	handle_file(path, NULL, rr_path(hex, "preimage"));
	267	fprintf(stderr, "Recorded preimage for '%s'\n", path);
	268	}
	269	}
	270
	271	/*
	272	* Now some of the paths that had conflicts earlier might have been
	273	* hand resolved. Others may be similar to a conflict already that
	274	* was resolved before.
	275	*/
	276
	277	for (i = 0; i < rr->nr; i++) {
	278	int ret;
c455c87c	279	const char *path = rr->items[i].string;
5b2fd956 SB	280	const char name = (const char )rr->items[i].util;
	281
	282	if (has_resolution(name)) {
	283	if (!merge(name, path)) {
5b2fd956	284	if (rerere_autoupdate)
c455c87c	285	string_list_insert(path, &update);
9196e825 JH	286	fprintf(stderr,
	287	"%s '%s' using previous resolution.\n",
	288	rerere_autoupdate
	289	? "Staged" : "Resolved",
	290	path);
5b2fd956 SB	291	goto mark_resolved;
	292	}
	293	}
	294
	295	/* Let's see if we have resolved it. */
	296	ret = handle_file(path, NULL, NULL);
	297	if (ret)
	298	continue;
	299
	300	fprintf(stderr, "Recorded resolution for '%s'.\n", path);
	301	copy_file(rr_path(name, "postimage"), path, 0666);
	302	mark_resolved:
	303	rr->items[i].util = NULL;
	304	}
	305
	306	if (update.nr)
	307	update_paths(&update);
	308
	309	return write_rr(rr, fd);
	310	}
	311
	312	static int git_rerere_config(const char var, const char value, void *cb)
	313	{
	314	if (!strcmp(var, "rerere.enabled"))
	315	rerere_enabled = git_config_bool(var, value);
	316	else if (!strcmp(var, "rerere.autoupdate"))
	317	rerere_autoupdate = git_config_bool(var, value);
	318	else
	319	return git_default_config(var, value, cb);
	320	return 0;
	321	}
	322
	323	static int is_rerere_enabled(void)
	324	{
	325	struct stat st;
	326	const char *rr_cache;
	327	int rr_cache_exists;
	328
	329	if (!rerere_enabled)
	330	return 0;
	331
	332	rr_cache = git_path("rr-cache");
	333	rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
	334	if (rerere_enabled < 0)
	335	return rr_cache_exists;
	336
	337	if (!rr_cache_exists &&
	338	(mkdir(rr_cache, 0777) \|\| adjust_shared_perm(rr_cache)))
	339	die("Could not create directory %s", rr_cache);
	340	return 1;
	341	}
	342
c455c87c	343	int setup_rerere(struct string_list *merge_rr)
5b2fd956 SB	344	{
	345	int fd;
	346
	347	git_config(git_rerere_config, NULL);
	348	if (!is_rerere_enabled())
	349	return -1;
	350
ebcffb1d	351	merge_rr_path = xstrdup(git_path("MERGE_RR"));
5b2fd956 SB	352	fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
	353	read_rr(merge_rr);
	354	return fd;
	355	}
	356
	357	int rerere(void)
	358	{
c455c87c	359	struct string_list merge_rr = { NULL, 0, 0, 1 };
5b2fd956 SB	360	int fd;
	361
	362	fd = setup_rerere(&merge_rr);
	363	if (fd < 0)
	364	return 0;
	365	return do_plain_rerere(&merge_rr, fd);
	366	}