[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 enum ll_merge_result (*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 enum ll_merge_result 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)
{
	enum ll_merge_result ret;
	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;
		ret = LL_MERGE_OK;
	} else {
		switch (opts->variant) {
		default:
			ret = LL_MERGE_BINARY_CONFLICT;
			stolen = src1;
			break;
		case XDL_MERGE_FAVOR_OURS:
			ret = LL_MERGE_OK;
			stolen = src1;
			break;
		case XDL_MERGE_FAVOR_THEIRS:
			ret = LL_MERGE_OK;
			stolen = src2;
			break;
		}
	}

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

	return ret;
}

static enum ll_merge_result 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)
{
	enum ll_merge_result ret;
	xmparam_t xmp;
	int status;
	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;
	status = xdl_merge(orig, src1, src2, &xmp, result);
	ret = (status > 0) ? LL_MERGE_CONFLICT : status;
	return ret;
}

static enum ll_merge_result 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 enum ll_merge_result 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;
	enum ll_merge_result ret;
	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)
		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);
	ret = (status > 0) ? LL_MERGE_CONFLICT : status;
	return ret;
}

/*
 * 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 UNUSED)
{
	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);
	}
}

enum ll_merge_result 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
35f69671	17	typedef enum ll_merge_result (ll_merge_fn)(const struct ll_merge_driver ,
525ab639 JH	18	mmbuffer_t *result,
525ab639 JH	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	*/
35f69671	52	static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv_unused,
525ab639	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	{
35f69671	61	enum ll_merge_result ret;
712516bc JN	62	mmfile_t *stolen;
	63	assert(opts);
	64
525ab639	65	/*
ed34567c JH	66	* The tentative merge result is the common ancestor for an
	67	* internal merge. For the final merge, it is "ours" by
	68	* default but -Xours/-Xtheirs can tweak the choice.
525ab639	69	*/
a944af1d JH	70	if (opts->virtual_ancestor) {
a944af1d JH	71	stolen = orig;
35f69671	72	ret = LL_MERGE_OK;
a944af1d JH	73	} else {
	74	switch (opts->variant) {
	75	default:
35f69671 EN	76	ret = LL_MERGE_BINARY_CONFLICT;
	77	stolen = src1;
	78	break;
a944af1d	79	case XDL_MERGE_FAVOR_OURS:
35f69671	80	ret = LL_MERGE_OK;
a944af1d JH	81	stolen = src1;
	82	break;
	83	case XDL_MERGE_FAVOR_THEIRS:
35f69671	84	ret = LL_MERGE_OK;
a944af1d JH	85	stolen = src2;
	86	break;
	87	}
	88	}
525ab639 JH	89
	90	result->ptr = stolen->ptr;
	91	result->size = stolen->size;
	92	stolen->ptr = NULL;
a944af1d	93
35f69671	94	return ret;
525ab639 JH	95	}
525ab639 JH	96
35f69671	97	static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unused,
525ab639	98	mmbuffer_t *result,
606475f3	99	const char *path,
f01de62e	100	mmfile_t orig, const char orig_name,
525ab639 JH	101	mmfile_t src1, const char name1,
525ab639 JH	102	mmfile_t src2, const char name2,
712516bc JN	103	const struct ll_merge_options *opts,
712516bc JN	104	int marker_size)
525ab639	105	{
35f69671	106	enum ll_merge_result ret;
00f8f97d	107	xmparam_t xmp;
35f69671	108	int status;
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;
a4b5e91c JN	135	xmp.file2 = name2;
35f69671 EN	136	status = xdl_merge(orig, src1, src2, &xmp, result);
	137	ret = (status > 0) ? LL_MERGE_CONFLICT : status;
	138	return ret;
525ab639 JH	139	}
525ab639 JH	140
35f69671	141	static enum ll_merge_result ll_union_merge(const struct ll_merge_driver *drv_unused,
525ab639	142	mmbuffer_t *result,
382b601a	143	const char *path,
f01de62e	144	mmfile_t orig, const char orig_name,
525ab639 JH	145	mmfile_t src1, const char name1,
525ab639 JH	146	mmfile_t src2, const char name2,
712516bc JN	147	const struct ll_merge_options *opts,
712516bc JN	148	int marker_size)
525ab639	149	{
cd1d61c4	150	/* Use union favor */
712516bc JN	151	struct ll_merge_options o;
	152	assert(opts);
	153	o = *opts;
	154	o.variant = XDL_MERGE_FAVOR_UNION;
382b601a	155	return ll_xdl_merge(drv_unused, result, path,
7f53f78b	156	orig, orig_name, src1, name1, src2, name2,
712516bc	157	&o, marker_size);
525ab639 JH	158	}
	159
	160	#define LL_BINARY_MERGE 0
	161	#define LL_TEXT_MERGE 1
	162	#define LL_UNION_MERGE 2
	163	static struct ll_merge_driver ll_merge_drv[] = {
	164	{ "binary", "built-in binary merge", ll_binary_merge },
	165	{ "text", "built-in 3-way text merge", ll_xdl_merge },
	166	{ "union", "built-in union merge", ll_union_merge },
	167	};
	168
5096d490	169	static void create_temp(mmfile_t src, char path, size_t len)
525ab639 JH	170	{
	171	int fd;
	172
5096d490	173	xsnprintf(path, len, ".merge_file_XXXXXX");
525ab639	174	fd = xmkstemp(path);
06f46f23	175	if (write_in_full(fd, src->ptr, src->size) < 0)
0721c314	176	die_errno("unable to write temp-file");
525ab639 JH	177	close(fd);
	178	}
	179
	180	/*
	181	* User defined low-level merge driver support.
	182	*/
35f69671	183	static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
525ab639 JH	184	mmbuffer_t *result,
525ab639 JH	185	const char *path,
f01de62e	186	mmfile_t orig, const char orig_name,
525ab639 JH	187	mmfile_t src1, const char name1,
525ab639 JH	188	mmfile_t src2, const char name2,
712516bc JN	189	const struct ll_merge_options *opts,
712516bc JN	190	int marker_size)
525ab639	191	{
23a64c9e	192	char temp[4][50];
ced621b2	193	struct strbuf cmd = STRBUF_INIT;
ef45bb1f JH	194	struct strbuf_expand_dict_entry dict[6];
ef45bb1f JH	195	struct strbuf path_sq = STRBUF_INIT;
ac0ba18d	196	const char *args[] = { NULL, NULL };
525ab639 JH	197	int status, fd, i;
525ab639 JH	198	struct stat st;
35f69671	199	enum ll_merge_result ret;
712516bc	200	assert(opts);
525ab639	201
ef45bb1f	202	sq_quote_buf(&path_sq, path);
66dbfd55 GV	203	dict[0].placeholder = "O"; dict[0].value = temp[0];
	204	dict[1].placeholder = "A"; dict[1].value = temp[1];
	205	dict[2].placeholder = "B"; dict[2].value = temp[2];
	206	dict[3].placeholder = "L"; dict[3].value = temp[3];
ef45bb1f JH	207	dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
ef45bb1f JH	208	dict[5].placeholder = NULL; dict[5].value = NULL;
66dbfd55	209
afe8a907	210	if (!fn->cmdline)
525ab639 JH	211	die("custom merge driver %s lacks command line.", fn->name);
	212
	213	result->ptr = NULL;
	214	result->size = 0;
5096d490 JK	215	create_temp(orig, temp[0], sizeof(temp[0]));
	216	create_temp(src1, temp[1], sizeof(temp[1]));
	217	create_temp(src2, temp[2], sizeof(temp[2]));
	218	xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
525ab639	219
ced621b2	220	strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
525ab639	221
ac0ba18d JK	222	args[0] = cmd.buf;
ac0ba18d JK	223	status = run_command_v_opt(args, RUN_USING_SHELL);
525ab639 JH	224	fd = open(temp[1], O_RDONLY);
	225	if (fd < 0)
	226	goto bad;
	227	if (fstat(fd, &st))
	228	goto close_bad;
	229	result->size = st.st_size;
3733e694	230	result->ptr = xmallocz(result->size);
525ab639	231	if (read_in_full(fd, result->ptr, result->size) != result->size) {
e140f7af	232	FREE_AND_NULL(result->ptr);
525ab639 JH	233	result->size = 0;
	234	}
	235	close_bad:
	236	close(fd);
	237	bad:
	238	for (i = 0; i < 3; i++)
691f1a28	239	unlink_or_warn(temp[i]);
ced621b2	240	strbuf_release(&cmd);
ef45bb1f	241	strbuf_release(&path_sq);
35f69671 EN	242	ret = (status > 0) ? LL_MERGE_CONFLICT : status;
35f69671 EN	243	return ret;
525ab639 JH	244	}
	245
	246	/*
	247	* merge.default and merge.driver configuration items
	248	*/
	249	static struct ll_merge_driver ll_user_merge, *ll_user_merge_tail;
	250	static const char *default_ll_merge;
	251
783a86c1	252	static int read_merge_config(const char var, const char value,
5cf88fd8	253	void *cb UNUSED)
525ab639 JH	254	{
525ab639 JH	255	struct ll_merge_driver *fn;
d731f0ad	256	const char key, name;
f5914f4b	257	size_t namelen;
525ab639	258
6ea358f7 TA	259	if (!strcmp(var, "merge.default"))
6ea358f7 TA	260	return git_config_string(&default_ll_merge, var, value);
525ab639 JH	261
	262	/*
	263	* We are not interested in anything but "merge.<name>.variable";
	264	* especially, we do not want to look at variables such as
	265	* "merge.summary", "merge.tool", and "merge.verbosity".
	266	*/
d731f0ad	267	if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 \|\| !name)
525ab639 JH	268	return 0;
	269
	270	/*
	271	* Find existing one as we might be processing merge.<name>.var2
	272	* after seeing merge.<name>.var1.
	273	*/
525ab639 JH	274	for (fn = ll_user_merge; fn; fn = fn->next)
	275	if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
	276	break;
	277	if (!fn) {
ca56dadb	278	CALLOC_ARRAY(fn, 1);
525ab639 JH	279	fn->name = xmemdupz(name, namelen);
	280	fn->fn = ll_ext_merge;
	281	*ll_user_merge_tail = fn;
	282	ll_user_merge_tail = &(fn->next);
	283	}
	284
6ea358f7 TA	285	if (!strcmp("name", key))
6ea358f7 TA	286	return git_config_string(&fn->description, var, value);
525ab639	287
d731f0ad	288	if (!strcmp("driver", key)) {
525ab639 JH	289	if (!value)
	290	return error("%s: lacks value", var);
	291	/*
	292	* merge.<name>.driver specifies the command line:
	293	*
	294	* command-line
	295	*
	296	* The command-line will be interpolated with the following
	297	* tokens and is given to the shell:
	298	*
	299	* %O - temporary file name for the merge base.
	300	* %A - temporary file name for our version.
	301	* %B - temporary file name for the other branches' version.
23a64c9e	302	* %L - conflict marker length
ef45bb1f	303	* %P - the original path (safely quoted for the shell)
525ab639 JH	304	*
	305	* The external merge driver should write the results in the
	306	* file named by %A, and signal that it has done with zero exit
	307	* status.
	308	*/
90dce515	309	fn->cmdline = xstrdup(value);
525ab639 JH	310	return 0;
	311	}
	312
6ea358f7 TA	313	if (!strcmp("recursive", key))
6ea358f7 TA	314	return git_config_string(&fn->recursive, var, value);
525ab639 JH	315
	316	return 0;
	317	}
	318
	319	static void initialize_ll_merge(void)
	320	{
	321	if (ll_user_merge_tail)
	322	return;
	323	ll_user_merge_tail = &ll_user_merge;
ef90d6d4	324	git_config(read_merge_config, NULL);
525ab639 JH	325	}
	326
	327	static const struct ll_merge_driver find_ll_merge_driver(const char merge_attr)
	328	{
	329	struct ll_merge_driver *fn;
	330	const char *name;
	331	int i;
	332
	333	initialize_ll_merge();
	334
	335	if (ATTR_TRUE(merge_attr))
	336	return &ll_merge_drv[LL_TEXT_MERGE];
	337	else if (ATTR_FALSE(merge_attr))
	338	return &ll_merge_drv[LL_BINARY_MERGE];
	339	else if (ATTR_UNSET(merge_attr)) {
	340	if (!default_ll_merge)
	341	return &ll_merge_drv[LL_TEXT_MERGE];
	342	else
	343	name = default_ll_merge;
	344	}
	345	else
	346	name = merge_attr;
	347
	348	for (fn = ll_user_merge; fn; fn = fn->next)
	349	if (!strcmp(fn->name, name))
	350	return fn;
	351
	352	for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
	353	if (!strcmp(ll_merge_drv[i].name, name))
	354	return &ll_merge_drv[i];
	355
	356	/* default to the 3-way */
	357	return &ll_merge_drv[LL_TEXT_MERGE];
	358	}
	359
32eaa468	360	static void normalize_file(mmfile_t mm, const char path, struct index_state *istate)
f217f0e8 EB	361	{
f217f0e8 EB	362	struct strbuf strbuf = STRBUF_INIT;
32eaa468	363	if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
f217f0e8 EB	364	free(mm->ptr);
	365	mm->size = strbuf.len;
	366	mm->ptr = strbuf_detach(&strbuf, NULL);
	367	}
	368	}
	369
35f69671	370	enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
525ab639	371	const char *path,
f01de62e	372	mmfile_t ancestor, const char ancestor_label,
525ab639 JH	373	mmfile_t ours, const char our_label,
525ab639 JH	374	mmfile_t theirs, const char their_label,
32eaa468	375	struct index_state *istate,
712516bc	376	const struct ll_merge_options *opts)
525ab639	377	{
2c65d90f	378	struct attr_check *check = load_merge_attributes();
4fb40c2b	379	static const struct ll_merge_options default_opts;
23a64c9e JH	380	const char *ll_driver_name = NULL;
23a64c9e JH	381	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
525ab639 JH	382	const struct ll_merge_driver *driver;
525ab639 JH	383
4fb40c2b JN	384	if (!opts)
4fb40c2b JN	385	opts = &default_opts;
712516bc JN	386
712516bc JN	387	if (opts->renormalize) {
32eaa468 NTND	388	normalize_file(ancestor, path, istate);
	389	normalize_file(ours, path, istate);
	390	normalize_file(theirs, path, istate);
f217f0e8	391	}
2aef63d3	392
11877b9e	393	git_check_attr(istate, path, check);
d64324cb TB	394	ll_driver_name = check->items[0].value;
	395	if (check->items[1].value) {
	396	marker_size = atoi(check->items[1].value);
	397	if (marker_size <= 0)
	398	marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
23a64c9e	399	}
525ab639	400	driver = find_ll_merge_driver(ll_driver_name);
d694a179 JH	401
	402	if (opts->virtual_ancestor) {
	403	if (driver->recursive)
	404	driver = find_ll_merge_driver(driver->recursive);
b2a7942b EN	405	}
	406	if (opts->extra_marker_size) {
	407	marker_size += opts->extra_marker_size;
d694a179	408	}
f01de62e	409	return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
23a64c9e	410	ours, our_label, theirs, their_label,
712516bc	411	opts, marker_size);
525ab639	412	}
8588567c	413
32eaa468	414	int ll_merge_marker_size(struct index_state istate, const char path)
8588567c	415	{
2aef63d3	416	static struct attr_check *check;
8588567c JH	417	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
8588567c JH	418
2aef63d3 JH	419	if (!check)
2aef63d3 JH	420	check = attr_check_initl("conflict-marker-size", NULL);
11877b9e	421	git_check_attr(istate, path, check);
d64324cb	422	if (check->items[0].value) {
2aef63d3	423	marker_size = atoi(check->items[0].value);
8588567c JH	424	if (marker_size <= 0)
	425	marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
	426	}
	427	return marker_size;
525ab639	428	}