[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;

const char *rerere_path(const char *hex, const char *file)
{
	return git_path("rr-cache/%s/%s", hex, file);
}

int has_rerere_resolution(const char *hex)
{
	struct stat st;
	return !stat(rerere_path(hex, "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_str_in_full(out_fd, "\t") != 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 void ferr_write(const void *p, size_t count, FILE *fp, int *err)
{
	if (!count || *err)
		return;
	if (fwrite(p, count, 1, fp) != 1)
		*err = errno;
}

static inline void ferr_puts(const char *s, FILE *fp, int *err)
{
	ferr_write(s, strlen(s), fp, err);
}

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

	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)
		git_SHA1_Init(&ctx);

	while (!strbuf_getwholeline(&buf, f, '\n')) {
		if (!prefixcmp(buf.buf, "<<<<<<< ")) {
			if (hunk != RR_CONTEXT)
				goto bad;
			hunk = RR_SIDE_1;
		} else if (!prefixcmp(buf.buf, "|||||||") && isspace(buf.buf[7])) {
			if (hunk != RR_SIDE_1)
				goto bad;
			hunk = RR_ORIGINAL;
		} else if (!prefixcmp(buf.buf, "=======") && isspace(buf.buf[7])) {
			if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
				goto bad;
			hunk = RR_SIDE_2;
		} else if (!prefixcmp(buf.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) {
				ferr_puts("<<<<<<<\n", out, &wrerror);
				ferr_write(one.buf, one.len, out, &wrerror);
				ferr_puts("=======\n", out, &wrerror);
				ferr_write(two.buf, two.len, out, &wrerror);
				ferr_puts(">>>>>>>\n", out, &wrerror);
			}
			if (sha1) {
				git_SHA1_Update(&ctx, one.buf ? one.buf : "",
					    one.len + 1);
				git_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.buf);
		else if (hunk == RR_ORIGINAL)
			; /* discard */
		else if (hunk == RR_SIDE_2)
			strbuf_addstr(&two, buf.buf);
		else if (out)
			ferr_puts(buf.buf, out, &wrerror);
		continue;
	bad:
		hunk = 99; /* force error exit */
		break;
	}
	strbuf_release(&one);
	strbuf_release(&two);
	strbuf_release(&buf);

	fclose(f);
	if (wrerror)
		error("There were errors while writing %s (%s)",
		      path, strerror(wrerror));
	if (out && fclose(out))
		wrerror = error("Failed to flush %s: %s",
				path, strerror(errno));
	if (sha1)
		git_SHA1_Final(sha1, &ctx);
	if (hunk != RR_CONTEXT) {
		if (output)
			unlink_or_warn(output);
		return error("Could not parse conflict hunks in %s", path);
	}
	if (wrerror)
		return -1;
	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, rerere_path(name, "thisimage")) < 0)
		return 1;

	if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
			read_mmfile(&base, rerere_path(name, "preimage")) ||
			read_mmfile(&other, rerere_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 open %s: %s", path,
				     strerror(errno));
		if (fwrite(result.ptr, result.size, 1, f) != 1)
			error("Could not write %s: %s", path, strerror(errno));
		if (fclose(f))
			return error("Writing %s failed: %s", path,
				     strerror(errno));
	}

	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, rerere_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_rerere_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(rerere_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)
{
	const char *rr_cache;
	int rr_cache_exists;

	if (!rerere_enabled)
		return 0;

	rr_cache = git_path("rr-cache");
	rr_cache_exists = is_directory(rr_cache);
	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 = git_pathdup("MERGE_RR");
	fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
				       LOCK_DIE_ON_ERROR);
	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
90056966	15	const char rerere_path(const char hex, const char *file)
5b2fd956	16	{
90056966	17	return git_path("rr-cache/%s/%s", hex, file);
5b2fd956 SB	18	}
5b2fd956 SB	19
90056966	20	int has_rerere_resolution(const char *hex)
5b2fd956 SB	21	{
5b2fd956 SB	22	struct stat st;
90056966	23	return !stat(rerere_path(hex, "postimage"), &st);
5b2fd956 SB	24	}
5b2fd956 SB	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;
5b2fd956 SB	63	if (write_in_full(out_fd, rr->items[i].util, 40) != 40 \|\|
2b7ca830	64	write_str_in_full(out_fd, "\t") != 1 \|\|
5b2fd956 SB	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
47d32af2 AR	73	static void ferr_write(const void p, size_t count, FILE fp, int *err)
	74	{
	75	if (!count \|\| *err)
	76	return;
	77	if (fwrite(p, count, 1, fp) != 1)
	78	*err = errno;
	79	}
	80
	81	static inline void ferr_puts(const char s, FILE fp, int *err)
	82	{
	83	ferr_write(s, strlen(s), fp, err);
	84	}
	85
5b2fd956 SB	86	static int handle_file(const char *path,
	87	unsigned char sha1, const char output)
	88	{
9126f009	89	git_SHA_CTX ctx;
cc58d7df JH	90	int hunk_no = 0;
cc58d7df JH	91	enum {
387c9d49	92	RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
cc58d7df	93	} hunk = RR_CONTEXT;
f285a2d7	94	struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
d58ee6db	95	struct strbuf buf = STRBUF_INIT;
5b2fd956 SB	96	FILE *f = fopen(path, "r");
5b2fd956 SB	97	FILE *out = NULL;
47d32af2	98	int wrerror = 0;
5b2fd956 SB	99
	100	if (!f)
	101	return error("Could not open %s", path);
	102
	103	if (output) {
	104	out = fopen(output, "w");
	105	if (!out) {
	106	fclose(f);
	107	return error("Could not write %s", output);
	108	}
	109	}
	110
	111	if (sha1)
9126f009	112	git_SHA1_Init(&ctx);
5b2fd956	113
d58ee6db JH	114	while (!strbuf_getwholeline(&buf, f, '\n')) {
d58ee6db JH	115	if (!prefixcmp(buf.buf, "<<<<<<< ")) {
cc58d7df	116	if (hunk != RR_CONTEXT)
5b2fd956	117	goto bad;
cc58d7df	118	hunk = RR_SIDE_1;
d58ee6db	119	} else if (!prefixcmp(buf.buf, "\|\|\|\|\|\|\|") && isspace(buf.buf[7])) {
cc58d7df	120	if (hunk != RR_SIDE_1)
5b2fd956	121	goto bad;
387c9d49	122	hunk = RR_ORIGINAL;
d58ee6db	123	} else if (!prefixcmp(buf.buf, "=======") && isspace(buf.buf[7])) {
387c9d49	124	if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
5b2fd956	125	goto bad;
cc58d7df	126	hunk = RR_SIDE_2;
d58ee6db	127	} else if (!prefixcmp(buf.buf, ">>>>>>> ")) {
cc58d7df	128	if (hunk != RR_SIDE_2)
5b2fd956 SB	129	goto bad;
	130	if (strbuf_cmp(&one, &two) > 0)
	131	strbuf_swap(&one, &two);
	132	hunk_no++;
cc58d7df	133	hunk = RR_CONTEXT;
5b2fd956	134	if (out) {
47d32af2 AR	135	ferr_puts("<<<<<<<\n", out, &wrerror);
	136	ferr_write(one.buf, one.len, out, &wrerror);
	137	ferr_puts("=======\n", out, &wrerror);
	138	ferr_write(two.buf, two.len, out, &wrerror);
	139	ferr_puts(">>>>>>>\n", out, &wrerror);
5b2fd956 SB	140	}
5b2fd956 SB	141	if (sha1) {
9126f009	142	git_SHA1_Update(&ctx, one.buf ? one.buf : "",
5b2fd956	143	one.len + 1);
9126f009	144	git_SHA1_Update(&ctx, two.buf ? two.buf : "",
5b2fd956 SB	145	two.len + 1);
	146	}
	147	strbuf_reset(&one);
	148	strbuf_reset(&two);
cc58d7df	149	} else if (hunk == RR_SIDE_1)
d58ee6db	150	strbuf_addstr(&one, buf.buf);
387c9d49 JH	151	else if (hunk == RR_ORIGINAL)
387c9d49 JH	152	; /* discard */
cc58d7df	153	else if (hunk == RR_SIDE_2)
d58ee6db	154	strbuf_addstr(&two, buf.buf);
5b2fd956	155	else if (out)
d58ee6db	156	ferr_puts(buf.buf, out, &wrerror);
5b2fd956 SB	157	continue;
	158	bad:
	159	hunk = 99; /* force error exit */
	160	break;
	161	}
	162	strbuf_release(&one);
	163	strbuf_release(&two);
d58ee6db	164	strbuf_release(&buf);
5b2fd956 SB	165
5b2fd956 SB	166	fclose(f);
47d32af2 AR	167	if (wrerror)
	168	error("There were errors while writing %s (%s)",
	169	path, strerror(wrerror));
	170	if (out && fclose(out))
	171	wrerror = error("Failed to flush %s: %s",
	172	path, strerror(errno));
5b2fd956	173	if (sha1)
9126f009	174	git_SHA1_Final(sha1, &ctx);
cc58d7df	175	if (hunk != RR_CONTEXT) {
5b2fd956	176	if (output)
691f1a28	177	unlink_or_warn(output);
5b2fd956 SB	178	return error("Could not parse conflict hunks in %s", path);
5b2fd956 SB	179	}
47d32af2 AR	180	if (wrerror)
47d32af2 AR	181	return -1;
5b2fd956 SB	182	return hunk_no;
	183	}
	184
c455c87c	185	static int find_conflict(struct string_list *conflict)
5b2fd956 SB	186	{
	187	int i;
	188	if (read_cache() < 0)
	189	return error("Could not read index");
	190	for (i = 0; i+1 < active_nr; i++) {
	191	struct cache_entry *e2 = active_cache[i];
	192	struct cache_entry *e3 = active_cache[i+1];
	193	if (ce_stage(e2) == 2 &&
	194	ce_stage(e3) == 3 &&
	195	ce_same_name(e2, e3) &&
	196	S_ISREG(e2->ce_mode) &&
	197	S_ISREG(e3->ce_mode)) {
c455c87c	198	string_list_insert((const char *)e2->name, conflict);
5b2fd956 SB	199	i++; /* skip over both #2 and #3 */
	200	}
	201	}
	202	return 0;
	203	}
	204
	205	static int merge(const char name, const char path)
	206	{
	207	int ret;
	208	mmfile_t cur, base, other;
	209	mmbuffer_t result = {NULL, 0};
	210	xpparam_t xpp = {XDF_NEED_MINIMAL};
	211
90056966	212	if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
5b2fd956 SB	213	return 1;
5b2fd956 SB	214
90056966 SG	215	if (read_mmfile(&cur, rerere_path(name, "thisimage")) \|\|
	216	read_mmfile(&base, rerere_path(name, "preimage")) \|\|
	217	read_mmfile(&other, rerere_path(name, "postimage")))
5b2fd956 SB	218	return 1;
	219	ret = xdl_merge(&base, &cur, "", &other, "",
	220	&xpp, XDL_MERGE_ZEALOUS, &result);
	221	if (!ret) {
	222	FILE *f = fopen(path, "w");
	223	if (!f)
47d32af2 AR	224	return error("Could not open %s: %s", path,
	225	strerror(errno));
	226	if (fwrite(result.ptr, result.size, 1, f) != 1)
	227	error("Could not write %s: %s", path, strerror(errno));
	228	if (fclose(f))
	229	return error("Writing %s failed: %s", path,
	230	strerror(errno));
5b2fd956 SB	231	}
	232
	233	free(cur.ptr);
	234	free(base.ptr);
	235	free(other.ptr);
	236	free(result.ptr);
	237
	238	return ret;
	239	}
	240
	241	static struct lock_file index_lock;
	242
c455c87c	243	static int update_paths(struct string_list *update)
5b2fd956 SB	244	{
	245	int i;
	246	int fd = hold_locked_index(&index_lock, 0);
	247	int status = 0;
	248
	249	if (fd < 0)
	250	return -1;
	251
	252	for (i = 0; i < update->nr; i++) {
c455c87c JS	253	struct string_list_item *item = &update->items[i];
c455c87c JS	254	if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
5b2fd956 SB	255	status = -1;
	256	}
	257
	258	if (!status && active_cache_changed) {
	259	if (write_cache(fd, active_cache, active_nr) \|\|
	260	commit_locked_index(&index_lock))
	261	die("Unable to write new index file");
	262	} else if (fd >= 0)
	263	rollback_lock_file(&index_lock);
	264	return status;
	265	}
	266
c455c87c	267	static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956	268	{
c455c87c JS	269	struct string_list conflict = { NULL, 0, 0, 1 };
c455c87c JS	270	struct string_list update = { NULL, 0, 0, 1 };
5b2fd956 SB	271	int i;
	272
	273	find_conflict(&conflict);
	274
	275	/*
	276	* MERGE_RR records paths with conflicts immediately after merge
	277	* failed. Some of the conflicted paths might have been hand resolved
	278	* in the working tree since then, but the initial run would catch all
	279	* and register their preimages.
	280	*/
	281
	282	for (i = 0; i < conflict.nr; i++) {
c455c87c JS	283	const char *path = conflict.items[i].string;
c455c87c JS	284	if (!string_list_has_string(rr, path)) {
5b2fd956 SB	285	unsigned char sha1[20];
	286	char *hex;
	287	int ret;
	288	ret = handle_file(path, sha1, NULL);
	289	if (ret < 1)
	290	continue;
	291	hex = xstrdup(sha1_to_hex(sha1));
c455c87c	292	string_list_insert(path, rr)->util = hex;
5b2fd956	293	if (mkdir(git_path("rr-cache/%s", hex), 0755))
ba19a808	294	continue;
90056966	295	handle_file(path, NULL, rerere_path(hex, "preimage"));
5b2fd956 SB	296	fprintf(stderr, "Recorded preimage for '%s'\n", path);
	297	}
	298	}
	299
	300	/*
	301	* Now some of the paths that had conflicts earlier might have been
	302	* hand resolved. Others may be similar to a conflict already that
	303	* was resolved before.
	304	*/
	305
	306	for (i = 0; i < rr->nr; i++) {
	307	int ret;
c455c87c	308	const char *path = rr->items[i].string;
5b2fd956 SB	309	const char name = (const char )rr->items[i].util;
5b2fd956 SB	310
90056966	311	if (has_rerere_resolution(name)) {
5b2fd956	312	if (!merge(name, path)) {
5b2fd956	313	if (rerere_autoupdate)
c455c87c	314	string_list_insert(path, &update);
9196e825 JH	315	fprintf(stderr,
	316	"%s '%s' using previous resolution.\n",
	317	rerere_autoupdate
	318	? "Staged" : "Resolved",
	319	path);
5b2fd956 SB	320	goto mark_resolved;
	321	}
	322	}
	323
	324	/* Let's see if we have resolved it. */
	325	ret = handle_file(path, NULL, NULL);
	326	if (ret)
	327	continue;
	328
	329	fprintf(stderr, "Recorded resolution for '%s'.\n", path);
90056966	330	copy_file(rerere_path(name, "postimage"), path, 0666);
5b2fd956 SB	331	mark_resolved:
	332	rr->items[i].util = NULL;
	333	}
	334
	335	if (update.nr)
	336	update_paths(&update);
	337
	338	return write_rr(rr, fd);
	339	}
	340
	341	static int git_rerere_config(const char var, const char value, void *cb)
	342	{
	343	if (!strcmp(var, "rerere.enabled"))
	344	rerere_enabled = git_config_bool(var, value);
	345	else if (!strcmp(var, "rerere.autoupdate"))
	346	rerere_autoupdate = git_config_bool(var, value);
	347	else
	348	return git_default_config(var, value, cb);
	349	return 0;
	350	}
	351
	352	static int is_rerere_enabled(void)
	353	{
5b2fd956 SB	354	const char *rr_cache;
	355	int rr_cache_exists;
	356
	357	if (!rerere_enabled)
	358	return 0;
	359
	360	rr_cache = git_path("rr-cache");
90b4a71c	361	rr_cache_exists = is_directory(rr_cache);
5b2fd956 SB	362	if (rerere_enabled < 0)
	363	return rr_cache_exists;
	364
	365	if (!rr_cache_exists &&
	366	(mkdir(rr_cache, 0777) \|\| adjust_shared_perm(rr_cache)))
	367	die("Could not create directory %s", rr_cache);
	368	return 1;
	369	}
	370
c455c87c	371	int setup_rerere(struct string_list *merge_rr)
5b2fd956 SB	372	{
	373	int fd;
	374
	375	git_config(git_rerere_config, NULL);
	376	if (!is_rerere_enabled())
	377	return -1;
	378
a4f34cbb	379	merge_rr_path = git_pathdup("MERGE_RR");
acd3b9ec JH	380	fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
acd3b9ec JH	381	LOCK_DIE_ON_ERROR);
5b2fd956 SB	382	read_rr(merge_rr);
	383	return fd;
	384	}
	385
	386	int rerere(void)
	387	{
c455c87c	388	struct string_list merge_rr = { NULL, 0, 0, 1 };
5b2fd956 SB	389	int fd;
	390
	391	fd = setup_rerere(&merge_rr);
	392	if (fd < 0)
	393	return 0;
	394	return do_plain_rerere(&merge_rr, fd);
	395	}