[thirdparty/git.git] / diff.c

/*
 * Copyright (C) 2005 Junio C Hamano
 */
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <limits.h>
#include "cache.h"
#include "diff.h"

static char *diff_opts = "-pu";

static const char *external_diff(void)
{
	static char *external_diff_cmd = NULL;
	static int done_preparing = 0;

	if (done_preparing)
		return external_diff_cmd;

	/*
	 * Default values above are meant to match the
	 * Linux kernel development style.  Examples of
	 * alternative styles you can specify via environment
	 * variables are:
	 *
	 * GIT_DIFF_OPTS="-c";
	 */
	if (getenv("GIT_EXTERNAL_DIFF"))
		external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");

	/* In case external diff fails... */
	diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;

	done_preparing = 1;
	return external_diff_cmd;
}

/* Help to copy the thing properly quoted for the shell safety.
 * any single quote is replaced with '\'', and the caller is
 * expected to enclose the result within a single quote pair.
 *
 * E.g.
 *  original     sq_expand     result
 *  name     ==> name      ==> 'name'
 *  a b      ==> a b       ==> 'a b'
 *  a'b      ==> a'\''b    ==> 'a'\''b'
 */
static char *sq_expand(const char *src)
{
	static char *buf = NULL;
	int cnt, c;
	const char *cp;
	char *bp;

	/* count bytes needed to store the quoted string. */ 
	for (cnt = 1, cp = src; *cp; cnt++, cp++)
		if (*cp == '\'')
			cnt += 3;

	buf = xmalloc(cnt);
	bp = buf;
	while ((c = *src++)) {
		if (c != '\'')
			*bp++ = c;
		else {
			bp = strcpy(bp, "'\\''");
			bp += 4;
		}
	}
	*bp = 0;
	return buf;
}

static struct diff_tempfile {
	const char *name;
	char hex[41];
	char mode[10];
	char tmp_path[50];
} diff_temp[2];

static void builtin_diff(const char *name,
			 struct diff_tempfile *temp)
{
	int i, next_at;
	const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
	const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
	const char *input_name_sq[2];
	const char *path0[2];
	const char *path1[2];
	const char *name_sq = sq_expand(name);
	char *cmd;
	
	/* diff_cmd and diff_arg have 6 %s in total which makes
	 * the sum of these strings 12 bytes larger than required.
	 * we use 2 spaces around diff-opts, and we need to count
	 * terminating NUL, so we subtract 9 here.
	 */
	int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
			strlen(diff_arg) - 9);
	for (i = 0; i < 2; i++) {
		input_name_sq[i] = sq_expand(temp[i].name);
		if (!strcmp(temp[i].name, "/dev/null")) {
			path0[i] = "/dev/null";
			path1[i] = "";
		} else {
			path0[i] = i ? "b/" : "a/";
			path1[i] = name_sq;
		}
		cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
			     strlen(input_name_sq[i]));
	}

	cmd = xmalloc(cmd_size);

	next_at = 0;
	next_at += snprintf(cmd+next_at, cmd_size-next_at,
			    diff_cmd,
			    path0[0], path1[0], path0[1], path1[1]);
	next_at += snprintf(cmd+next_at, cmd_size-next_at,
			    " %s ", diff_opts);
	next_at += snprintf(cmd+next_at, cmd_size-next_at,
			    diff_arg, input_name_sq[0], input_name_sq[1]);

	if (!path1[0][0])
		printf("Created: %s (mode:%s)\n", name, temp[1].mode);
	else if (!path1[1][0])
		printf("Deleted: %s\n", name);
	else if (strcmp(temp[0].mode, temp[1].mode)) {
		printf("Mode changed: %s (%s->%s)\n", name,
		       temp[0].mode, temp[1].mode);
		/* Be careful.  We do not want to diff between
		 * symlink and a file.
		 */
		if (strncmp(temp[0].mode, "120", 3) !=
		    strncmp(temp[1].mode, "120", 3))
			exit(0);
	}
	fflush(NULL);
	execlp("/bin/sh","sh", "-c", cmd, NULL);
}

/*
 * Given a name and sha1 pair, if the dircache tells us the file in
 * the work tree has that object contents, return true, so that
 * prepare_temp_file() does not have to inflate and extract.
 */
static int work_tree_matches(const char *name, const unsigned char *sha1)
{
	struct cache_entry *ce;
	struct stat st;
	int pos, len;
	
	/* We do not read the cache ourselves here, because the
	 * benchmark with my previous version that always reads cache
	 * shows that it makes things worse for diff-tree comparing
	 * two linux-2.6 kernel trees in an already checked out work
	 * tree.  This is because most diff-tree comparison deals with
	 * only a small number of files, while reading the cache is
	 * expensive for a large project, and its cost outweighs the
	 * savings we get by not inflating the object to a temporary
	 * file.  Practically, this code only helps when we are used
	 * by diff-cache --cached, which does read the cache before
	 * calling us.
	 */ 
	if (!active_cache)
		return 0;

	len = strlen(name);
	pos = cache_name_pos(name, len);
	if (pos < 0)
		return 0;
	ce = active_cache[pos];
	if ((lstat(name, &st) < 0) ||
	    !S_ISREG(st.st_mode) ||
	    cache_match_stat(ce, &st) ||
	    memcmp(sha1, ce->sha1, 20))
		return 0;
	return 1;
}

static void prep_temp_blob(struct diff_tempfile *temp,
			   void *blob,
			   unsigned long size,
			   unsigned char *sha1,
			   int mode)
{
	int fd;

	strcpy(temp->tmp_path, ".diff_XXXXXX");
	fd = mkstemp(temp->tmp_path);
	if (fd < 0)
		die("unable to create temp-file");
	if (write(fd, blob, size) != size)
		die("unable to write temp-file");
	close(fd);
	temp->name = temp->tmp_path;
	strcpy(temp->hex, sha1_to_hex(sha1));
	temp->hex[40] = 0;
	sprintf(temp->mode, "%06o", mode);
}

static void prepare_temp_file(const char *name,
			      struct diff_tempfile *temp,
			      struct diff_spec *one)
{
	static unsigned char null_sha1[20] = { 0, };
	int use_work_tree = 0;

	if (!one->file_valid) {
	not_a_valid_file:
		/* A '-' entry produces this for file-2, and
		 * a '+' entry produces this for file-1.
		 */
		temp->name = "/dev/null";
		strcpy(temp->hex, ".");
		strcpy(temp->mode, ".");
		return;
	}

	if (one->sha1_valid &&
	    (!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
	     work_tree_matches(name, one->blob_sha1)))
		use_work_tree = 1;

	if (!one->sha1_valid || use_work_tree) {
		struct stat st;
		temp->name = name;
		if (lstat(temp->name, &st) < 0) {
			if (errno == ENOENT)
				goto not_a_valid_file;
			die("stat(%s): %s", temp->name, strerror(errno));
		}
		if (S_ISLNK(st.st_mode)) {
			int ret;
			char *buf, buf_[1024];
			buf = ((sizeof(buf_) < st.st_size) ?
			       xmalloc(st.st_size) : buf_);
			ret = readlink(name, buf, st.st_size);
			if (ret < 0)
				die("readlink(%s)", name);
			prep_temp_blob(temp, buf, st.st_size,
				       (one->sha1_valid ?
					one->blob_sha1 : null_sha1),
				       (one->sha1_valid ?
					one->mode : S_IFLNK));
		}
		else {
			if (!one->sha1_valid)
				strcpy(temp->hex, sha1_to_hex(null_sha1));
			else
				strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
			sprintf(temp->mode, "%06o",
				S_IFREG |ce_permissions(st.st_mode));
		}
		return;
	}
	else {
		void *blob;
		char type[20];
		unsigned long size;

		blob = read_sha1_file(one->blob_sha1, type, &size);
		if (!blob || strcmp(type, "blob"))
			die("unable to read blob object for %s (%s)",
			    name, sha1_to_hex(one->blob_sha1));
		prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
		free(blob);
	}
}

static void remove_tempfile(void)
{
	int i;

	for (i = 0; i < 2; i++)
		if (diff_temp[i].name == diff_temp[i].tmp_path) {
			unlink(diff_temp[i].name);
			diff_temp[i].name = NULL;
		}
}

static void remove_tempfile_on_signal(int signo)
{
	remove_tempfile();
}

/* An external diff command takes:
 *
 * diff-cmd name infile1 infile1-sha1 infile1-mode \
 *               infile2 infile2-sha1 infile2-mode.
 *
 */
void run_external_diff(const char *name,
		       struct diff_spec *one,
		       struct diff_spec *two)
{
	struct diff_tempfile *temp = diff_temp;
	pid_t pid;
	int status;
	static int atexit_asked = 0;

	if (one && two) {
		prepare_temp_file(name, &temp[0], one);
		prepare_temp_file(name, &temp[1], two);
		if (! atexit_asked &&
		    (temp[0].name == temp[0].tmp_path ||
		     temp[1].name == temp[1].tmp_path)) {
			atexit_asked = 1;
			atexit(remove_tempfile);
		}
		signal(SIGINT, remove_tempfile_on_signal);
	}

	fflush(NULL);
	pid = fork();
	if (pid < 0)
		die("unable to fork");
	if (!pid) {
		const char *pgm = external_diff();
		if (pgm) {
			if (one && two)
				execlp(pgm, pgm,
				       name,
				       temp[0].name, temp[0].hex, temp[0].mode,
				       temp[1].name, temp[1].hex, temp[1].mode,
				       NULL);
			else
				execlp(pgm, pgm, name, NULL);
		}
		/*
		 * otherwise we use the built-in one.
		 */
		if (one && two)
			builtin_diff(name, temp);
		else
			printf("* Unmerged path %s\n", name);
		exit(0);
	}
	if (waitpid(pid, &status, 0) < 0 ||
	    !WIFEXITED(status) || WEXITSTATUS(status)) {
		/* Earlier we did not check the exit status because
		 * diff exits non-zero if files are different, and
		 * we are not interested in knowing that.  It was a
		 * mistake which made it harder to quit a diff-*
		 * session that uses the git-apply-patch-script as
		 * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
		 * should also exit non-zero only when it wants to
		 * abort the entire diff-* session.
		 */
		remove_tempfile();
		fprintf(stderr, "external diff died, stopping at %s.\n", name);
		exit(1);
	}
	remove_tempfile();
}

void diff_addremove(int addremove, unsigned mode,
		    const unsigned char *sha1,
		    const char *base, const char *path)
{
	char concatpath[PATH_MAX];
	struct diff_spec spec[2], *one, *two;

	memcpy(spec[0].blob_sha1, sha1, 20);
	spec[0].mode = mode;
	spec[0].sha1_valid = spec[0].file_valid = 1;
	spec[1].file_valid = 0;

	if (addremove == '+') {
		one = spec + 1; two = spec;
	} else {
		one = spec; two = one + 1;
	}
	
	if (path) {
		strcpy(concatpath, base);
		strcat(concatpath, path);
	}
	run_external_diff(path ? concatpath : base, one, two);
}

void diff_change(unsigned old_mode, unsigned new_mode,
		 const unsigned char *old_sha1,
		 const unsigned char *new_sha1,
		 const char *base, const char *path) {
	char concatpath[PATH_MAX];
	struct diff_spec spec[2];

	memcpy(spec[0].blob_sha1, old_sha1, 20);
	spec[0].mode = old_mode;
	memcpy(spec[1].blob_sha1, new_sha1, 20);
	spec[1].mode = new_mode;
	spec[0].sha1_valid = spec[0].file_valid = 1;
	spec[1].sha1_valid = spec[1].file_valid = 1;

	if (path) {
		strcpy(concatpath, base);
		strcat(concatpath, path);
	}
	run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
}

void diff_unmerge(const char *path)
{
	run_external_diff(path, NULL, NULL);
}
Commit	Line	Data
be3cfa85 JH	1	/*
	2	* Copyright (C) 2005 Junio C Hamano
	3	*/
	4	#include <sys/types.h>
	5	#include <sys/wait.h>
532149d7	6	#include <signal.h>
a1df57ab	7	#include <limits.h>
86436c28 JH	8	#include "cache.h"
	9	#include "diff.h"
	10
be3cfa85	11	static char *diff_opts = "-pu";
86436c28	12
be3cfa85	13	static const char *external_diff(void)
86436c28	14	{
be3cfa85 JH	15	static char *external_diff_cmd = NULL;
	16	static int done_preparing = 0;
	17
	18	if (done_preparing)
	19	return external_diff_cmd;
	20
86436c28 JH	21	/*
	22	* Default values above are meant to match the
	23	* Linux kernel development style. Examples of
	24	* alternative styles you can specify via environment
	25	* variables are:
	26	*
86436c28 JH	27	* GIT_DIFF_OPTS="-c";
86436c28 JH	28	*/
be3cfa85 JH	29	if (getenv("GIT_EXTERNAL_DIFF"))
	30	external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
	31
	32	/* In case external diff fails... */
86436c28	33	diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
be3cfa85 JH	34
	35	done_preparing = 1;
	36	return external_diff_cmd;
86436c28 JH	37	}
	38
	39	/* Help to copy the thing properly quoted for the shell safety.
	40	* any single quote is replaced with '\'', and the caller is
	41	* expected to enclose the result within a single quote pair.
	42	*
	43	* E.g.
	44	* original sq_expand result
	45	* name ==> name ==> 'name'
	46	* a b ==> a b ==> 'a b'
	47	* a'b ==> a'\''b ==> 'a'\''b'
	48	*/
	49	static char sq_expand(const char src)
	50	{
	51	static char *buf = NULL;
	52	int cnt, c;
	53	const char *cp;
	54	char *bp;
	55
	56	/* count bytes needed to store the quoted string. */
	57	for (cnt = 1, cp = src; *cp; cnt++, cp++)
	58	if (*cp == '\'')
	59	cnt += 3;
	60
812666c8	61	buf = xmalloc(cnt);
86436c28 JH	62	bp = buf;
	63	while ((c = *src++)) {
	64	if (c != '\'')
	65	*bp++ = c;
	66	else {
	67	bp = strcpy(bp, "'\\''");
	68	bp += 4;
	69	}
	70	}
	71	*bp = 0;
	72	return buf;
	73	}
	74
be3cfa85 JH	75	static struct diff_tempfile {
	76	const char *name;
	77	char hex[41];
	78	char mode[10];
	79	char tmp_path[50];
	80	} diff_temp[2];
	81
	82	static void builtin_diff(const char *name,
	83	struct diff_tempfile *temp)
86436c28	84	{
2f978138	85	int i, next_at;
c983370e	86	const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
6fa28064	87	const char diff_arg = "'%s' '%s'\|\|:"; / "\|\|:" is to return 0 */
2f978138 JH	88	const char *input_name_sq[2];
	89	const char *path0[2];
	90	const char *path1[2];
be3cfa85	91	const char *name_sq = sq_expand(name);
2f978138 JH	92	char *cmd;
2f978138 JH	93
c983370e JH	94	/* diff_cmd and diff_arg have 6 %s in total which makes
c983370e JH	95	* the sum of these strings 12 bytes larger than required.
be3cfa85	96	* we use 2 spaces around diff-opts, and we need to count
c983370e	97	* terminating NUL, so we subtract 9 here.
be3cfa85	98	*/
2f978138	99	int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
c983370e	100	strlen(diff_arg) - 9);
2f978138 JH	101	for (i = 0; i < 2; i++) {
	102	input_name_sq[i] = sq_expand(temp[i].name);
	103	if (!strcmp(temp[i].name, "/dev/null")) {
	104	path0[i] = "/dev/null";
	105	path1[i] = "";
2f978138	106	} else {
0980d9b3	107	path0[i] = i ? "b/" : "a/";
2f978138	108	path1[i] = name_sq;
2f978138 JH	109	}
2f978138 JH	110	cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
c983370e	111	strlen(input_name_sq[i]));
2f978138	112	}
be3cfa85	113
2f978138 JH	114	cmd = xmalloc(cmd_size);
	115
	116	next_at = 0;
be3cfa85	117	next_at += snprintf(cmd+next_at, cmd_size-next_at,
2f978138	118	diff_cmd,
c983370e	119	path0[0], path1[0], path0[1], path1[1]);
be3cfa85 JH	120	next_at += snprintf(cmd+next_at, cmd_size-next_at,
	121	" %s ", diff_opts);
	122	next_at += snprintf(cmd+next_at, cmd_size-next_at,
2f978138 JH	123	diff_arg, input_name_sq[0], input_name_sq[1]);
2f978138 JH	124
c983370e JH	125	if (!path1[0][0])
	126	printf("Created: %s (mode:%s)\n", name, temp[1].mode);
	127	else if (!path1[1][0])
	128	printf("Deleted: %s\n", name);
b28858bf	129	else if (strcmp(temp[0].mode, temp[1].mode)) {
c983370e JH	130	printf("Mode changed: %s (%s->%s)\n", name,
c983370e JH	131	temp[0].mode, temp[1].mode);
b28858bf JH	132	/* Be careful. We do not want to diff between
	133	* symlink and a file.
	134	*/
	135	if (strncmp(temp[0].mode, "120", 3) !=
	136	strncmp(temp[1].mode, "120", 3))
	137	exit(0);
	138	}
c983370e	139	fflush(NULL);
be3cfa85	140	execlp("/bin/sh","sh", "-c", cmd, NULL);
86436c28 JH	141	}
86436c28 JH	142
b46f0b6d JH	143	/*
	144	* Given a name and sha1 pair, if the dircache tells us the file in
	145	* the work tree has that object contents, return true, so that
	146	* prepare_temp_file() does not have to inflate and extract.
	147	*/
	148	static int work_tree_matches(const char name, const unsigned char sha1)
	149	{
	150	struct cache_entry *ce;
	151	struct stat st;
	152	int pos, len;
	153
	154	/* We do not read the cache ourselves here, because the
	155	* benchmark with my previous version that always reads cache
	156	* shows that it makes things worse for diff-tree comparing
	157	* two linux-2.6 kernel trees in an already checked out work
	158	* tree. This is because most diff-tree comparison deals with
	159	* only a small number of files, while reading the cache is
	160	* expensive for a large project, and its cost outweighs the
	161	* savings we get by not inflating the object to a temporary
	162	* file. Practically, this code only helps when we are used
	163	* by diff-cache --cached, which does read the cache before
	164	* calling us.
	165	*/
	166	if (!active_cache)
	167	return 0;
	168
	169	len = strlen(name);
	170	pos = cache_name_pos(name, len);
	171	if (pos < 0)
	172	return 0;
	173	ce = active_cache[pos];
b28858bf JH	174	if ((lstat(name, &st) < 0) \|\|
b28858bf JH	175	!S_ISREG(st.st_mode) \|\|
b46f0b6d JH	176	cache_match_stat(ce, &st) \|\|
	177	memcmp(sha1, ce->sha1, 20))
	178	return 0;
	179	return 1;
	180	}
	181
b28858bf JH	182	static void prep_temp_blob(struct diff_tempfile *temp,
	183	void *blob,
	184	unsigned long size,
	185	unsigned char *sha1,
	186	int mode)
	187	{
	188	int fd;
	189
	190	strcpy(temp->tmp_path, ".diff_XXXXXX");
	191	fd = mkstemp(temp->tmp_path);
	192	if (fd < 0)
	193	die("unable to create temp-file");
	194	if (write(fd, blob, size) != size)
	195	die("unable to write temp-file");
	196	close(fd);
	197	temp->name = temp->tmp_path;
	198	strcpy(temp->hex, sha1_to_hex(sha1));
	199	temp->hex[40] = 0;
	200	sprintf(temp->mode, "%06o", mode);
	201	}
	202
be3cfa85 JH	203	static void prepare_temp_file(const char *name,
	204	struct diff_tempfile *temp,
	205	struct diff_spec *one)
86436c28	206	{
be3cfa85	207	static unsigned char null_sha1[20] = { 0, };
b46f0b6d	208	int use_work_tree = 0;
be3cfa85 JH	209
	210	if (!one->file_valid) {
	211	not_a_valid_file:
532149d7 JH	212	/* A '-' entry produces this for file-2, and
	213	* a '+' entry produces this for file-1.
	214	*/
be3cfa85 JH	215	temp->name = "/dev/null";
	216	strcpy(temp->hex, ".");
	217	strcpy(temp->mode, ".");
86436c28 JH	218	return;
86436c28 JH	219	}
be3cfa85 JH	220
be3cfa85 JH	221	if (one->sha1_valid &&
b46f0b6d JH	222	(!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) \|\|
	223	work_tree_matches(name, one->blob_sha1)))
	224	use_work_tree = 1;
be3cfa85	225
b46f0b6d	226	if (!one->sha1_valid \|\| use_work_tree) {
be3cfa85	227	struct stat st;
b46f0b6d	228	temp->name = name;
b28858bf	229	if (lstat(temp->name, &st) < 0) {
be3cfa85 JH	230	if (errno == ENOENT)
	231	goto not_a_valid_file;
	232	die("stat(%s): %s", temp->name, strerror(errno));
	233	}
b28858bf JH	234	if (S_ISLNK(st.st_mode)) {
	235	int ret;
	236	char *buf, buf_[1024];
	237	buf = ((sizeof(buf_) < st.st_size) ?
	238	xmalloc(st.st_size) : buf_);
	239	ret = readlink(name, buf, st.st_size);
	240	if (ret < 0)
	241	die("readlink(%s)", name);
	242	prep_temp_blob(temp, buf, st.st_size,
	243	(one->sha1_valid ?
	244	one->blob_sha1 : null_sha1),
	245	(one->sha1_valid ?
	246	one->mode : S_IFLNK));
	247	}
	248	else {
	249	if (!one->sha1_valid)
	250	strcpy(temp->hex, sha1_to_hex(null_sha1));
	251	else
	252	strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
	253	sprintf(temp->mode, "%06o",
	254	S_IFREG \|ce_permissions(st.st_mode));
	255	}
	256	return;
be3cfa85 JH	257	}
be3cfa85 JH	258	else {
be3cfa85 JH	259	void *blob;
	260	char type[20];
	261	unsigned long size;
	262
b46f0b6d	263	blob = read_sha1_file(one->blob_sha1, type, &size);
be3cfa85 JH	264	if (!blob \|\| strcmp(type, "blob"))
be3cfa85 JH	265	die("unable to read blob object for %s (%s)",
b46f0b6d	266	name, sha1_to_hex(one->blob_sha1));
b28858bf	267	prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
be3cfa85	268	free(blob);
be3cfa85 JH	269	}
	270	}
	271
	272	static void remove_tempfile(void)
	273	{
	274	int i;
	275
	276	for (i = 0; i < 2; i++)
	277	if (diff_temp[i].name == diff_temp[i].tmp_path) {
	278	unlink(diff_temp[i].name);
	279	diff_temp[i].name = NULL;
	280	}
	281	}
	282
532149d7 JH	283	static void remove_tempfile_on_signal(int signo)
	284	{
	285	remove_tempfile();
	286	}
	287
be3cfa85 JH	288	/* An external diff command takes:
	289	*
	290	* diff-cmd name infile1 infile1-sha1 infile1-mode \
	291	* infile2 infile2-sha1 infile2-mode.
	292	*
	293	*/
	294	void run_external_diff(const char *name,
	295	struct diff_spec *one,
	296	struct diff_spec *two)
	297	{
	298	struct diff_tempfile *temp = diff_temp;
532149d7 JH	299	pid_t pid;
532149d7 JH	300	int status;
be3cfa85 JH	301	static int atexit_asked = 0;
be3cfa85 JH	302
77eb2720 JH	303	if (one && two) {
	304	prepare_temp_file(name, &temp[0], one);
	305	prepare_temp_file(name, &temp[1], two);
	306	if (! atexit_asked &&
	307	(temp[0].name == temp[0].tmp_path \|\|
	308	temp[1].name == temp[1].tmp_path)) {
	309	atexit_asked = 1;
	310	atexit(remove_tempfile);
	311	}
532149d7	312	signal(SIGINT, remove_tempfile_on_signal);
be3cfa85 JH	313	}
	314
	315	fflush(NULL);
	316	pid = fork();
	317	if (pid < 0)
	318	die("unable to fork");
	319	if (!pid) {
	320	const char *pgm = external_diff();
77eb2720 JH	321	if (pgm) {
	322	if (one && two)
	323	execlp(pgm, pgm,
	324	name,
	325	temp[0].name, temp[0].hex, temp[0].mode,
	326	temp[1].name, temp[1].hex, temp[1].mode,
	327	NULL);
	328	else
	329	execlp(pgm, pgm, name, NULL);
	330	}
be3cfa85 JH	331	/*
	332	* otherwise we use the built-in one.
	333	*/
77eb2720 JH	334	if (one && two)
	335	builtin_diff(name, temp);
	336	else
	337	printf("* Unmerged path %s\n", name);
be3cfa85 JH	338	exit(0);
be3cfa85 JH	339	}
6fa28064 JH	340	if (waitpid(pid, &status, 0) < 0 \|\|
	341	!WIFEXITED(status) \|\| WEXITSTATUS(status)) {
	342	/* Earlier we did not check the exit status because
532149d7	343	* diff exits non-zero if files are different, and
6fa28064 JH	344	* we are not interested in knowing that. It was a
	345	* mistake which made it harder to quit a diff-*
	346	* session that uses the git-apply-patch-script as
	347	* the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
	348	* should also exit non-zero only when it wants to
	349	* abort the entire diff-* session.
532149d7 JH	350	*/
532149d7 JH	351	remove_tempfile();
6fa28064 JH	352	fprintf(stderr, "external diff died, stopping at %s.\n", name);
6fa28064 JH	353	exit(1);
532149d7	354	}
be3cfa85 JH	355	remove_tempfile();
	356	}
	357
77eb2720 JH	358	void diff_addremove(int addremove, unsigned mode,
	359	const unsigned char *sha1,
	360	const char base, const char path)
be3cfa85	361	{
77eb2720	362	char concatpath[PATH_MAX];
be3cfa85 JH	363	struct diff_spec spec[2], one, two;
be3cfa85 JH	364
b46f0b6d	365	memcpy(spec[0].blob_sha1, sha1, 20);
77eb2720	366	spec[0].mode = mode;
be3cfa85 JH	367	spec[0].sha1_valid = spec[0].file_valid = 1;
	368	spec[1].file_valid = 0;
	369
77eb2720	370	if (addremove == '+') {
be3cfa85 JH	371	one = spec + 1; two = spec;
	372	} else {
	373	one = spec; two = one + 1;
	374	}
77eb2720 JH	375
	376	if (path) {
	377	strcpy(concatpath, base);
77eb2720 JH	378	strcat(concatpath, path);
	379	}
	380	run_external_diff(path ? concatpath : base, one, two);
be3cfa85 JH	381	}
be3cfa85 JH	382
77eb2720 JH	383	void diff_change(unsigned old_mode, unsigned new_mode,
	384	const unsigned char *old_sha1,
	385	const unsigned char *new_sha1,
	386	const char base, const char path) {
	387	char concatpath[PATH_MAX];
	388	struct diff_spec spec[2];
	389
b46f0b6d	390	memcpy(spec[0].blob_sha1, old_sha1, 20);
77eb2720	391	spec[0].mode = old_mode;
b46f0b6d	392	memcpy(spec[1].blob_sha1, new_sha1, 20);
77eb2720	393	spec[1].mode = new_mode;
be3cfa85	394	spec[0].sha1_valid = spec[0].file_valid = 1;
77eb2720	395	spec[1].sha1_valid = spec[1].file_valid = 1;
be3cfa85	396
77eb2720 JH	397	if (path) {
77eb2720 JH	398	strcpy(concatpath, base);
77eb2720	399	strcat(concatpath, path);
be3cfa85	400	}
77eb2720 JH	401	run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
77eb2720 JH	402	}
be3cfa85	403
77eb2720 JH	404	void diff_unmerge(const char *path)
	405	{
	406	run_external_diff(path, NULL, NULL);
86436c28	407	}