[thirdparty/git.git] / ll-merge.c

/*
 * Low level 3-way in-core file merge.
 *
 * Copyright (c) 2007 Junio C Hamano
 */

#include "cache.h"
#include "config.h"
#include "attr.h"
#include "xdiff-interface.h"
#include "run-command.h"
#include "ll-merge.h"
#include "quote.h"

struct ll_merge_driver;

typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
			   mmbuffer_t *result,
			   const char *path,
			   mmfile_t *orig, const char *orig_name,
			   mmfile_t *src1, const char *name1,
			   mmfile_t *src2, const char *name2,
			   const struct ll_merge_options *opts,
			   int marker_size);

struct ll_merge_driver {
	const char *name;
	const char *description;
	ll_merge_fn fn;
	const char *recursive;
	struct ll_merge_driver *next;
	char *cmdline;
};

static struct attr_check *merge_attributes;
static struct attr_check *load_merge_attributes(void)
{
	if (!merge_attributes)
		merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
	return merge_attributes;
}

void reset_merge_attributes(void)
{
	attr_check_free(merge_attributes);
	merge_attributes = NULL;
}

/*
 * Built-in low-levels
 */
static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
			   mmbuffer_t *result,
			   const char *path,
			   mmfile_t *orig, const char *orig_name,
			   mmfile_t *src1, const char *name1,
			   mmfile_t *src2, const char *name2,
			   const struct ll_merge_options *opts,
			   int marker_size)
{
	mmfile_t *stolen;
	assert(opts);

	/*
	 * The tentative merge result is the common ancestor for an
	 * internal merge.  For the final merge, it is "ours" by
	 * default but -Xours/-Xtheirs can tweak the choice.
	 */
	if (opts->virtual_ancestor) {
		stolen = orig;
	} else {
		switch (opts->variant) {
		default:
			warning("Cannot merge binary files: %s (%s vs. %s)",
				path, name1, name2);
			/* fallthru */
		case XDL_MERGE_FAVOR_OURS:
			stolen = src1;
			break;
		case XDL_MERGE_FAVOR_THEIRS:
			stolen = src2;
			break;
		}
	}

	result->ptr = stolen->ptr;
	result->size = stolen->size;
	stolen->ptr = NULL;

	/*
	 * With -Xtheirs or -Xours, we have cleanly merged;
	 * otherwise we got a conflict.
	 */
	return opts->variant == XDL_MERGE_FAVOR_OURS ||
	       opts->variant == XDL_MERGE_FAVOR_THEIRS ?
	       0 : 1;
}

static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
			mmbuffer_t *result,
			const char *path,
			mmfile_t *orig, const char *orig_name,
			mmfile_t *src1, const char *name1,
			mmfile_t *src2, const char *name2,
			const struct ll_merge_options *opts,
			int marker_size)
{
	xmparam_t xmp;
	assert(opts);

	if (orig->size > MAX_XDIFF_SIZE ||
	    src1->size > MAX_XDIFF_SIZE ||
	    src2->size > MAX_XDIFF_SIZE ||
	    buffer_is_binary(orig->ptr, orig->size) ||
	    buffer_is_binary(src1->ptr, src1->size) ||
	    buffer_is_binary(src2->ptr, src2->size)) {
		return ll_binary_merge(drv_unused, result,
				       path,
				       orig, orig_name,
				       src1, name1,
				       src2, name2,
				       opts, marker_size);
	}

	memset(&xmp, 0, sizeof(xmp));
	xmp.level = XDL_MERGE_ZEALOUS;
	xmp.favor = opts->variant;
	xmp.xpp.flags = opts->xdl_opts;
	if (git_xmerge_style >= 0)
		xmp.style = git_xmerge_style;
	if (marker_size > 0)
		xmp.marker_size = marker_size;
	xmp.ancestor = orig_name;
	xmp.file1 = name1;
	xmp.file2 = name2;
	return xdl_merge(orig, src1, src2, &xmp, result);
}

static int ll_union_merge(const struct ll_merge_driver *drv_unused,
			  mmbuffer_t *result,
			  const char *path,
			  mmfile_t *orig, const char *orig_name,
			  mmfile_t *src1, const char *name1,
			  mmfile_t *src2, const char *name2,
			  const struct ll_merge_options *opts,
			  int marker_size)
{
	/* Use union favor */
	struct ll_merge_options o;
	assert(opts);
	o = *opts;
	o.variant = XDL_MERGE_FAVOR_UNION;
	return ll_xdl_merge(drv_unused, result, path,
			    orig, orig_name, src1, name1, src2, name2,
			    &o, marker_size);
}

#define LL_BINARY_MERGE 0
#define LL_TEXT_MERGE 1
#define LL_UNION_MERGE 2
static struct ll_merge_driver ll_merge_drv[] = {
	{ "binary", "built-in binary merge", ll_binary_merge },
	{ "text", "built-in 3-way text merge", ll_xdl_merge },
	{ "union", "built-in union merge", ll_union_merge },
};

static void create_temp(mmfile_t *src, char *path, size_t len)
{
	int fd;

	xsnprintf(path, len, ".merge_file_XXXXXX");
	fd = xmkstemp(path);
	if (write_in_full(fd, src->ptr, src->size) < 0)
		die_errno("unable to write temp-file");
	close(fd);
}

/*
 * User defined low-level merge driver support.
 */
static int ll_ext_merge(const struct ll_merge_driver *fn,
			mmbuffer_t *result,
			const char *path,
			mmfile_t *orig, const char *orig_name,
			mmfile_t *src1, const char *name1,
			mmfile_t *src2, const char *name2,
			const struct ll_merge_options *opts,
			int marker_size)
{
	char temp[4][50];
	struct strbuf cmd = STRBUF_INIT;
	struct strbuf_expand_dict_entry dict[6];
	struct strbuf path_sq = STRBUF_INIT;
	const char *args[] = { NULL, NULL };
	int status, fd, i;
	struct stat st;
	assert(opts);

	sq_quote_buf(&path_sq, path);
	dict[0].placeholder = "O"; dict[0].value = temp[0];
	dict[1].placeholder = "A"; dict[1].value = temp[1];
	dict[2].placeholder = "B"; dict[2].value = temp[2];
	dict[3].placeholder = "L"; dict[3].value = temp[3];
	dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
	dict[5].placeholder = NULL; dict[5].value = NULL;

	if (fn->cmdline == NULL)
		die("custom merge driver %s lacks command line.", fn->name);

	result->ptr = NULL;
	result->size = 0;
	create_temp(orig, temp[0], sizeof(temp[0]));
	create_temp(src1, temp[1], sizeof(temp[1]));
	create_temp(src2, temp[2], sizeof(temp[2]));
	xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);

	strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);

	args[0] = cmd.buf;
	status = run_command_v_opt(args, RUN_USING_SHELL);
	fd = open(temp[1], O_RDONLY);
	if (fd < 0)
		goto bad;
	if (fstat(fd, &st))
		goto close_bad;
	result->size = st.st_size;
	result->ptr = xmallocz(result->size);
	if (read_in_full(fd, result->ptr, result->size) != result->size) {
		FREE_AND_NULL(result->ptr);
		result->size = 0;
	}
 close_bad:
	close(fd);
 bad:
	for (i = 0; i < 3; i++)
		unlink_or_warn(temp[i]);
	strbuf_release(&cmd);
	strbuf_release(&path_sq);
	return status;
}

/*
 * merge.default and merge.driver configuration items
 */
static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
static const char *default_ll_merge;

static int read_merge_config(const char *var, const char *value, void *cb)
{
	struct ll_merge_driver *fn;
	const char *key, *name;
	size_t namelen;

	if (!strcmp(var, "merge.default"))
		return git_config_string(&default_ll_merge, var, value);

	/*
	 * We are not interested in anything but "merge.<name>.variable";
	 * especially, we do not want to look at variables such as
	 * "merge.summary", "merge.tool", and "merge.verbosity".
	 */
	if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
		return 0;

	/*
	 * Find existing one as we might be processing merge.<name>.var2
	 * after seeing merge.<name>.var1.
	 */
	for (fn = ll_user_merge; fn; fn = fn->next)
		if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
			break;
	if (!fn) {
		CALLOC_ARRAY(fn, 1);
		fn->name = xmemdupz(name, namelen);
		fn->fn = ll_ext_merge;
		*ll_user_merge_tail = fn;
		ll_user_merge_tail = &(fn->next);
	}

	if (!strcmp("name", key))
		return git_config_string(&fn->description, var, value);

	if (!strcmp("driver", key)) {
		if (!value)
			return error("%s: lacks value", var);
		/*
		 * merge.<name>.driver specifies the command line:
		 *
		 *	command-line
		 *
		 * The command-line will be interpolated with the following
		 * tokens and is given to the shell:
		 *
		 *    %O - temporary file name for the merge base.
		 *    %A - temporary file name for our version.
		 *    %B - temporary file name for the other branches' version.
		 *    %L - conflict marker length
		 *    %P - the original path (safely quoted for the shell)
		 *
		 * The external merge driver should write the results in the
		 * file named by %A, and signal that it has done with zero exit
		 * status.
		 */
		fn->cmdline = xstrdup(value);
		return 0;
	}

	if (!strcmp("recursive", key))
		return git_config_string(&fn->recursive, var, value);

	return 0;
}

static void initialize_ll_merge(void)
{
	if (ll_user_merge_tail)
		return;
	ll_user_merge_tail = &ll_user_merge;
	git_config(read_merge_config, NULL);
}

static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
{
	struct ll_merge_driver *fn;
	const char *name;
	int i;

	initialize_ll_merge();

	if (ATTR_TRUE(merge_attr))
		return &ll_merge_drv[LL_TEXT_MERGE];
	else if (ATTR_FALSE(merge_attr))
		return &ll_merge_drv[LL_BINARY_MERGE];
	else if (ATTR_UNSET(merge_attr)) {
		if (!default_ll_merge)
			return &ll_merge_drv[LL_TEXT_MERGE];
		else
			name = default_ll_merge;
	}
	else
		name = merge_attr;

	for (fn = ll_user_merge; fn; fn = fn->next)
		if (!strcmp(fn->name, name))
			return fn;

	for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
		if (!strcmp(ll_merge_drv[i].name, name))
			return &ll_merge_drv[i];

	/* default to the 3-way */
	return &ll_merge_drv[LL_TEXT_MERGE];
}

static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
{
	struct strbuf strbuf = STRBUF_INIT;
	if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
		free(mm->ptr);
		mm->size = strbuf.len;
		mm->ptr = strbuf_detach(&strbuf, NULL);
	}
}

int ll_merge(mmbuffer_t *result_buf,
	     const char *path,
	     mmfile_t *ancestor, const char *ancestor_label,
	     mmfile_t *ours, const char *our_label,
	     mmfile_t *theirs, const char *their_label,
	     struct index_state *istate,
	     const struct ll_merge_options *opts)
{
	struct attr_check *check = load_merge_attributes();
	static const struct ll_merge_options default_opts;
	const char *ll_driver_name = NULL;
	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
	const struct ll_merge_driver *driver;

	if (!opts)
		opts = &default_opts;

	if (opts->renormalize) {
		normalize_file(ancestor, path, istate);
		normalize_file(ours, path, istate);
		normalize_file(theirs, path, istate);
	}

	git_check_attr(istate, path, check);
	ll_driver_name = check->items[0].value;
	if (check->items[1].value) {
		marker_size = atoi(check->items[1].value);
		if (marker_size <= 0)
			marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
	}
	driver = find_ll_merge_driver(ll_driver_name);

	if (opts->virtual_ancestor) {
		if (driver->recursive)
			driver = find_ll_merge_driver(driver->recursive);
	}
	if (opts->extra_marker_size) {
		marker_size += opts->extra_marker_size;
	}
	return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
			  ours, our_label, theirs, their_label,
			  opts, marker_size);
}

int ll_merge_marker_size(struct index_state *istate, const char *path)
{
	static struct attr_check *check;
	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;

	if (!check)
		check = attr_check_initl("conflict-marker-size", NULL);
	git_check_attr(istate, path, check);
	if (check->items[0].value) {
		marker_size = atoi(check->items[0].value);
		if (marker_size <= 0)
			marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
	}
	return marker_size;
}
Commit	Line	Data
525ab639 JH	1	/*
	2	* Low level 3-way in-core file merge.
	3	*
	4	* Copyright (c) 2007 Junio C Hamano
	5	*/
	6
	7	#include "cache.h"
b2141fc1	8	#include "config.h"
525ab639 JH	9	#include "attr.h"
	10	#include "xdiff-interface.h"
	11	#include "run-command.h"
525ab639	12	#include "ll-merge.h"
ef45bb1f	13	#include "quote.h"
525ab639 JH	14
	15	struct ll_merge_driver;
	16
	17	typedef int (ll_merge_fn)(const struct ll_merge_driver ,
	18	mmbuffer_t *result,
	19	const char *path,
f01de62e	20	mmfile_t orig, const char orig_name,
525ab639 JH	21	mmfile_t src1, const char name1,
525ab639 JH	22	mmfile_t src2, const char name2,
712516bc	23	const struct ll_merge_options *opts,
23a64c9e	24	int marker_size);
525ab639 JH	25
	26	struct ll_merge_driver {
	27	const char *name;
	28	const char *description;
	29	ll_merge_fn fn;
	30	const char *recursive;
	31	struct ll_merge_driver *next;
	32	char *cmdline;
	33	};
	34
2c65d90f	35	static struct attr_check *merge_attributes;
	36	static struct attr_check *load_merge_attributes(void)
	37	{
	38	if (!merge_attributes)
	39	merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL);
	40	return merge_attributes;
	41	}
	42
	43	void reset_merge_attributes(void)
	44	{
	45	attr_check_free(merge_attributes);
	46	merge_attributes = NULL;
	47	}
	48
525ab639 JH	49	/*
	50	* Built-in low-levels
	51	*/
	52	static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
	53	mmbuffer_t *result,
e0e2065f	54	const char *path,
f01de62e	55	mmfile_t orig, const char orig_name,
525ab639 JH	56	mmfile_t src1, const char name1,
525ab639 JH	57	mmfile_t src2, const char name2,
712516bc JN	58	const struct ll_merge_options *opts,
712516bc JN	59	int marker_size)
525ab639	60	{
712516bc JN	61	mmfile_t *stolen;
	62	assert(opts);
	63
525ab639	64	/*
ed34567c JH	65	* The tentative merge result is the common ancestor for an
	66	* internal merge. For the final merge, it is "ours" by
	67	* default but -Xours/-Xtheirs can tweak the choice.
525ab639	68	*/
a944af1d JH	69	if (opts->virtual_ancestor) {
	70	stolen = orig;
	71	} else {
	72	switch (opts->variant) {
	73	default:
e6d29a4b	74	warning("Cannot merge binary files: %s (%s vs. %s)",
e0e2065f JH	75	path, name1, name2);
e0e2065f JH	76	/* fallthru */
a944af1d JH	77	case XDL_MERGE_FAVOR_OURS:
	78	stolen = src1;
	79	break;
	80	case XDL_MERGE_FAVOR_THEIRS:
	81	stolen = src2;
	82	break;
	83	}
	84	}
525ab639 JH	85
	86	result->ptr = stolen->ptr;
	87	result->size = stolen->size;
	88	stolen->ptr = NULL;
a944af1d JH	89
	90	/*
	91	* With -Xtheirs or -Xours, we have cleanly merged;
	92	* otherwise we got a conflict.
	93	*/
7d879ad7 JK	94	return opts->variant == XDL_MERGE_FAVOR_OURS \|\|
	95	opts->variant == XDL_MERGE_FAVOR_THEIRS ?
	96	0 : 1;
525ab639 JH	97	}
	98
	99	static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
	100	mmbuffer_t *result,
606475f3	101	const char *path,
f01de62e	102	mmfile_t orig, const char orig_name,
525ab639 JH	103	mmfile_t src1, const char name1,
525ab639 JH	104	mmfile_t src2, const char name2,
712516bc JN	105	const struct ll_merge_options *opts,
712516bc JN	106	int marker_size)
525ab639	107	{
00f8f97d	108	xmparam_t xmp;
712516bc	109	assert(opts);
525ab639	110
dcd1742e JK	111	if (orig->size > MAX_XDIFF_SIZE \|\|
	112	src1->size > MAX_XDIFF_SIZE \|\|
	113	src2->size > MAX_XDIFF_SIZE \|\|
	114	buffer_is_binary(orig->ptr, orig->size) \|\|
525ab639 JH	115	buffer_is_binary(src1->ptr, src1->size) \|\|
525ab639 JH	116	buffer_is_binary(src2->ptr, src2->size)) {
525ab639	117	return ll_binary_merge(drv_unused, result,
606475f3	118	path,
f01de62e JN	119	orig, orig_name,
f01de62e JN	120	src1, name1,
525ab639	121	src2, name2,
712516bc	122	opts, marker_size);
525ab639 JH	123	}
525ab639 JH	124
00f8f97d	125	memset(&xmp, 0, sizeof(xmp));
560119b9	126	xmp.level = XDL_MERGE_ZEALOUS;
712516bc	127	xmp.favor = opts->variant;
58a1ece4	128	xmp.xpp.flags = opts->xdl_opts;
c236bcd0	129	if (git_xmerge_style >= 0)
560119b9	130	xmp.style = git_xmerge_style;
23a64c9e JH	131	if (marker_size > 0)
23a64c9e JH	132	xmp.marker_size = marker_size;
f01de62e	133	xmp.ancestor = orig_name;
a4b5e91c JN	134	xmp.file1 = name1;
	135	xmp.file2 = name2;
	136	return xdl_merge(orig, src1, src2, &xmp, result);
525ab639 JH	137	}
	138
	139	static int ll_union_merge(const struct ll_merge_driver *drv_unused,
	140	mmbuffer_t *result,
382b601a	141	const char *path,
f01de62e	142	mmfile_t orig, const char orig_name,
525ab639 JH	143	mmfile_t src1, const char name1,
525ab639 JH	144	mmfile_t src2, const char name2,
712516bc JN	145	const struct ll_merge_options *opts,
712516bc JN	146	int marker_size)
525ab639	147	{
cd1d61c4	148	/* Use union favor */
712516bc JN	149	struct ll_merge_options o;
	150	assert(opts);
	151	o = *opts;
	152	o.variant = XDL_MERGE_FAVOR_UNION;
382b601a	153	return ll_xdl_merge(drv_unused, result, path,
7f53f78b	154	orig, orig_name, src1, name1, src2, name2,
712516bc	155	&o, marker_size);
525ab639 JH	156	}
	157
	158	#define LL_BINARY_MERGE 0
	159	#define LL_TEXT_MERGE 1
	160	#define LL_UNION_MERGE 2
	161	static struct ll_merge_driver ll_merge_drv[] = {
	162	{ "binary", "built-in binary merge", ll_binary_merge },
	163	{ "text", "built-in 3-way text merge", ll_xdl_merge },
	164	{ "union", "built-in union merge", ll_union_merge },
	165	};
	166
5096d490	167	static void create_temp(mmfile_t src, char path, size_t len)
525ab639 JH	168	{
	169	int fd;
	170
5096d490	171	xsnprintf(path, len, ".merge_file_XXXXXX");
525ab639	172	fd = xmkstemp(path);
06f46f23	173	if (write_in_full(fd, src->ptr, src->size) < 0)
0721c314	174	die_errno("unable to write temp-file");
525ab639 JH	175	close(fd);
	176	}
	177
	178	/*
	179	* User defined low-level merge driver support.
	180	*/
	181	static int ll_ext_merge(const struct ll_merge_driver *fn,
	182	mmbuffer_t *result,
	183	const char *path,
f01de62e	184	mmfile_t orig, const char orig_name,
525ab639 JH	185	mmfile_t src1, const char name1,
525ab639 JH	186	mmfile_t src2, const char name2,
712516bc JN	187	const struct ll_merge_options *opts,
712516bc JN	188	int marker_size)
525ab639	189	{
23a64c9e	190	char temp[4][50];
ced621b2	191	struct strbuf cmd = STRBUF_INIT;
ef45bb1f JH	192	struct strbuf_expand_dict_entry dict[6];
ef45bb1f JH	193	struct strbuf path_sq = STRBUF_INIT;
ac0ba18d	194	const char *args[] = { NULL, NULL };
525ab639 JH	195	int status, fd, i;
525ab639 JH	196	struct stat st;
712516bc	197	assert(opts);
525ab639	198
ef45bb1f	199	sq_quote_buf(&path_sq, path);
66dbfd55 GV	200	dict[0].placeholder = "O"; dict[0].value = temp[0];
	201	dict[1].placeholder = "A"; dict[1].value = temp[1];
	202	dict[2].placeholder = "B"; dict[2].value = temp[2];
	203	dict[3].placeholder = "L"; dict[3].value = temp[3];
ef45bb1f JH	204	dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
ef45bb1f JH	205	dict[5].placeholder = NULL; dict[5].value = NULL;
66dbfd55	206
525ab639 JH	207	if (fn->cmdline == NULL)
	208	die("custom merge driver %s lacks command line.", fn->name);
	209
	210	result->ptr = NULL;
	211	result->size = 0;
5096d490 JK	212	create_temp(orig, temp[0], sizeof(temp[0]));
	213	create_temp(src1, temp[1], sizeof(temp[1]));
	214	create_temp(src2, temp[2], sizeof(temp[2]));
	215	xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
525ab639	216
ced621b2	217	strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
525ab639	218
ac0ba18d JK	219	args[0] = cmd.buf;
ac0ba18d JK	220	status = run_command_v_opt(args, RUN_USING_SHELL);
525ab639 JH	221	fd = open(temp[1], O_RDONLY);
	222	if (fd < 0)
	223	goto bad;
	224	if (fstat(fd, &st))
	225	goto close_bad;
	226	result->size = st.st_size;
3733e694	227	result->ptr = xmallocz(result->size);
525ab639	228	if (read_in_full(fd, result->ptr, result->size) != result->size) {
e140f7af	229	FREE_AND_NULL(result->ptr);
525ab639 JH	230	result->size = 0;
	231	}
	232	close_bad:
	233	close(fd);
	234	bad:
	235	for (i = 0; i < 3; i++)
691f1a28	236	unlink_or_warn(temp[i]);
ced621b2	237	strbuf_release(&cmd);
ef45bb1f	238	strbuf_release(&path_sq);
525ab639 JH	239	return status;
	240	}
	241
	242	/*
	243	* merge.default and merge.driver configuration items
	244	*/
	245	static struct ll_merge_driver ll_user_merge, *ll_user_merge_tail;
	246	static const char *default_ll_merge;
	247
ef90d6d4	248	static int read_merge_config(const char var, const char value, void *cb)
525ab639 JH	249	{
525ab639 JH	250	struct ll_merge_driver *fn;
d731f0ad	251	const char key, name;
f5914f4b	252	size_t namelen;
525ab639	253
6ea358f7 TA	254	if (!strcmp(var, "merge.default"))
6ea358f7 TA	255	return git_config_string(&default_ll_merge, var, value);
525ab639 JH	256
	257	/*
	258	* We are not interested in anything but "merge.<name>.variable";
	259	* especially, we do not want to look at variables such as
	260	* "merge.summary", "merge.tool", and "merge.verbosity".
	261	*/
d731f0ad	262	if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 \|\| !name)
525ab639 JH	263	return 0;
	264
	265	/*
	266	* Find existing one as we might be processing merge.<name>.var2
	267	* after seeing merge.<name>.var1.
	268	*/
525ab639 JH	269	for (fn = ll_user_merge; fn; fn = fn->next)
	270	if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
	271	break;
	272	if (!fn) {
ca56dadb	273	CALLOC_ARRAY(fn, 1);
525ab639 JH	274	fn->name = xmemdupz(name, namelen);
	275	fn->fn = ll_ext_merge;
	276	*ll_user_merge_tail = fn;
	277	ll_user_merge_tail = &(fn->next);
	278	}
	279
6ea358f7 TA	280	if (!strcmp("name", key))
6ea358f7 TA	281	return git_config_string(&fn->description, var, value);
525ab639	282
d731f0ad	283	if (!strcmp("driver", key)) {
525ab639 JH	284	if (!value)
	285	return error("%s: lacks value", var);
	286	/*
	287	* merge.<name>.driver specifies the command line:
	288	*
	289	* command-line
	290	*
	291	* The command-line will be interpolated with the following
	292	* tokens and is given to the shell:
	293	*
	294	* %O - temporary file name for the merge base.
	295	* %A - temporary file name for our version.
	296	* %B - temporary file name for the other branches' version.
23a64c9e	297	* %L - conflict marker length
ef45bb1f	298	* %P - the original path (safely quoted for the shell)
525ab639 JH	299	*
	300	* The external merge driver should write the results in the
	301	* file named by %A, and signal that it has done with zero exit
	302	* status.
	303	*/
90dce515	304	fn->cmdline = xstrdup(value);
525ab639 JH	305	return 0;
	306	}
	307
6ea358f7 TA	308	if (!strcmp("recursive", key))
6ea358f7 TA	309	return git_config_string(&fn->recursive, var, value);
525ab639 JH	310
	311	return 0;
	312	}
	313
	314	static void initialize_ll_merge(void)
	315	{
	316	if (ll_user_merge_tail)
	317	return;
	318	ll_user_merge_tail = &ll_user_merge;
ef90d6d4	319	git_config(read_merge_config, NULL);
525ab639 JH	320	}
	321
	322	static const struct ll_merge_driver find_ll_merge_driver(const char merge_attr)
	323	{
	324	struct ll_merge_driver *fn;
	325	const char *name;
	326	int i;
	327
	328	initialize_ll_merge();
	329
	330	if (ATTR_TRUE(merge_attr))
	331	return &ll_merge_drv[LL_TEXT_MERGE];
	332	else if (ATTR_FALSE(merge_attr))
	333	return &ll_merge_drv[LL_BINARY_MERGE];
	334	else if (ATTR_UNSET(merge_attr)) {
	335	if (!default_ll_merge)
	336	return &ll_merge_drv[LL_TEXT_MERGE];
	337	else
	338	name = default_ll_merge;
	339	}
	340	else
	341	name = merge_attr;
	342
	343	for (fn = ll_user_merge; fn; fn = fn->next)
	344	if (!strcmp(fn->name, name))
	345	return fn;
	346
	347	for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
	348	if (!strcmp(ll_merge_drv[i].name, name))
	349	return &ll_merge_drv[i];
	350
	351	/* default to the 3-way */
	352	return &ll_merge_drv[LL_TEXT_MERGE];
	353	}
	354
32eaa468	355	static void normalize_file(mmfile_t mm, const char path, struct index_state *istate)
f217f0e8 EB	356	{
f217f0e8 EB	357	struct strbuf strbuf = STRBUF_INIT;
32eaa468	358	if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
f217f0e8 EB	359	free(mm->ptr);
	360	mm->size = strbuf.len;
	361	mm->ptr = strbuf_detach(&strbuf, NULL);
	362	}
	363	}
	364
525ab639 JH	365	int ll_merge(mmbuffer_t *result_buf,
525ab639 JH	366	const char *path,
f01de62e	367	mmfile_t ancestor, const char ancestor_label,
525ab639 JH	368	mmfile_t ours, const char our_label,
525ab639 JH	369	mmfile_t theirs, const char their_label,
32eaa468	370	struct index_state *istate,
712516bc	371	const struct ll_merge_options *opts)
525ab639	372	{
2c65d90f	373	struct attr_check *check = load_merge_attributes();
4fb40c2b	374	static const struct ll_merge_options default_opts;
23a64c9e JH	375	const char *ll_driver_name = NULL;
23a64c9e JH	376	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
525ab639 JH	377	const struct ll_merge_driver *driver;
525ab639 JH	378
4fb40c2b JN	379	if (!opts)
4fb40c2b JN	380	opts = &default_opts;
712516bc JN	381
712516bc JN	382	if (opts->renormalize) {
32eaa468 NTND	383	normalize_file(ancestor, path, istate);
	384	normalize_file(ours, path, istate);
	385	normalize_file(theirs, path, istate);
f217f0e8	386	}
2aef63d3	387
11877b9e	388	git_check_attr(istate, path, check);
d64324cb TB	389	ll_driver_name = check->items[0].value;
	390	if (check->items[1].value) {
	391	marker_size = atoi(check->items[1].value);
	392	if (marker_size <= 0)
	393	marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
23a64c9e	394	}
525ab639	395	driver = find_ll_merge_driver(ll_driver_name);
d694a179 JH	396
	397	if (opts->virtual_ancestor) {
	398	if (driver->recursive)
	399	driver = find_ll_merge_driver(driver->recursive);
b2a7942b EN	400	}
	401	if (opts->extra_marker_size) {
	402	marker_size += opts->extra_marker_size;
d694a179	403	}
f01de62e	404	return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
23a64c9e	405	ours, our_label, theirs, their_label,
712516bc	406	opts, marker_size);
525ab639	407	}
8588567c	408
32eaa468	409	int ll_merge_marker_size(struct index_state istate, const char path)
8588567c	410	{
2aef63d3	411	static struct attr_check *check;
8588567c JH	412	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
8588567c JH	413
2aef63d3 JH	414	if (!check)
2aef63d3 JH	415	check = attr_check_initl("conflict-marker-size", NULL);
11877b9e	416	git_check_attr(istate, path, check);
d64324cb	417	if (check->items[0].value) {
2aef63d3	418	marker_size = atoi(check->items[0].value);
8588567c JH	419	if (marker_size <= 0)
	420	marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
	421	}
	422	return marker_size;
525ab639	423	}