[thirdparty/git.git] / diff.c

/*
 * Copyright (C) 2005 Junio C Hamano
 */
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.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);
	fflush(NULL);
	execlp("/bin/sh","sh", "-c", cmd, NULL);
}

static void prepare_temp_file(const char *name,
			      struct diff_tempfile *temp,
			      struct diff_spec *one)
{
	static unsigned char null_sha1[20] = { 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->u.sha1, null_sha1, sizeof(null_sha1))) {
		one->sha1_valid = 0;
		one->u.name = name;
	}

	if (!one->sha1_valid) {
		struct stat st;
		temp->name = one->u.name;
		if (stat(temp->name, &st) < 0) {
			if (errno == ENOENT)
				goto not_a_valid_file;
			die("stat(%s): %s", temp->name, strerror(errno));
		}
		strcpy(temp->hex, sha1_to_hex(null_sha1));
		sprintf(temp->mode, "%06o",
			S_IFREG |ce_permissions(st.st_mode));
	}
	else {
		int fd;
		void *blob;
		char type[20];
		unsigned long size;

		blob = read_sha1_file(one->u.sha1, type, &size);
		if (!blob || strcmp(type, "blob"))
			die("unable to read blob object for %s (%s)",
			    name, sha1_to_hex(one->u.sha1));

		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);
		free(blob);
		temp->name = temp->tmp_path;
		strcpy(temp->hex, sha1_to_hex(one->u.sha1));
		temp->hex[40] = 0;
		sprintf(temp->mode, "%06o", one->mode);
	}
}

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].u.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].u.sha1, old_sha1, 20);
	spec[0].mode = old_mode;
	memcpy(spec[1].u.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>
86436c28 JH	7	#include "cache.h"
	8	#include "diff.h"
	9
be3cfa85	10	static char *diff_opts = "-pu";
86436c28	11
be3cfa85	12	static const char *external_diff(void)
86436c28	13	{
be3cfa85 JH	14	static char *external_diff_cmd = NULL;
	15	static int done_preparing = 0;
	16
	17	if (done_preparing)
	18	return external_diff_cmd;
	19
86436c28 JH	20	/*
	21	* Default values above are meant to match the
	22	* Linux kernel development style. Examples of
	23	* alternative styles you can specify via environment
	24	* variables are:
	25	*
86436c28 JH	26	* GIT_DIFF_OPTS="-c";
86436c28 JH	27	*/
be3cfa85 JH	28	if (getenv("GIT_EXTERNAL_DIFF"))
	29	external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
	30
	31	/* In case external diff fails... */
86436c28	32	diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
be3cfa85 JH	33
	34	done_preparing = 1;
	35	return external_diff_cmd;
86436c28 JH	36	}
	37
	38	/* Help to copy the thing properly quoted for the shell safety.
	39	* any single quote is replaced with '\'', and the caller is
	40	* expected to enclose the result within a single quote pair.
	41	*
	42	* E.g.
	43	* original sq_expand result
	44	* name ==> name ==> 'name'
	45	* a b ==> a b ==> 'a b'
	46	* a'b ==> a'\''b ==> 'a'\''b'
	47	*/
	48	static char sq_expand(const char src)
	49	{
	50	static char *buf = NULL;
	51	int cnt, c;
	52	const char *cp;
	53	char *bp;
	54
	55	/* count bytes needed to store the quoted string. */
	56	for (cnt = 1, cp = src; *cp; cnt++, cp++)
	57	if (*cp == '\'')
	58	cnt += 3;
	59
812666c8	60	buf = xmalloc(cnt);
86436c28 JH	61	bp = buf;
	62	while ((c = *src++)) {
	63	if (c != '\'')
	64	*bp++ = c;
	65	else {
	66	bp = strcpy(bp, "'\\''");
	67	bp += 4;
	68	}
	69	}
	70	*bp = 0;
	71	return buf;
	72	}
	73
be3cfa85 JH	74	static struct diff_tempfile {
	75	const char *name;
	76	char hex[41];
	77	char mode[10];
	78	char tmp_path[50];
	79	} diff_temp[2];
	80
	81	static void builtin_diff(const char *name,
	82	struct diff_tempfile *temp)
86436c28	83	{
2f978138	84	int i, next_at;
c983370e	85	const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
6fa28064	86	const char diff_arg = "'%s' '%s'\|\|:"; / "\|\|:" is to return 0 */
2f978138 JH	87	const char *input_name_sq[2];
	88	const char *path0[2];
	89	const char *path1[2];
be3cfa85	90	const char *name_sq = sq_expand(name);
2f978138 JH	91	char *cmd;
2f978138 JH	92
c983370e JH	93	/* diff_cmd and diff_arg have 6 %s in total which makes
c983370e JH	94	* the sum of these strings 12 bytes larger than required.
be3cfa85	95	* we use 2 spaces around diff-opts, and we need to count
c983370e	96	* terminating NUL, so we subtract 9 here.
be3cfa85	97	*/
2f978138	98	int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
c983370e	99	strlen(diff_arg) - 9);
2f978138 JH	100	for (i = 0; i < 2; i++) {
	101	input_name_sq[i] = sq_expand(temp[i].name);
	102	if (!strcmp(temp[i].name, "/dev/null")) {
	103	path0[i] = "/dev/null";
	104	path1[i] = "";
2f978138	105	} else {
0980d9b3	106	path0[i] = i ? "b/" : "a/";
2f978138	107	path1[i] = name_sq;
2f978138 JH	108	}
2f978138 JH	109	cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
c983370e	110	strlen(input_name_sq[i]));
2f978138	111	}
be3cfa85	112
2f978138 JH	113	cmd = xmalloc(cmd_size);
	114
	115	next_at = 0;
be3cfa85	116	next_at += snprintf(cmd+next_at, cmd_size-next_at,
2f978138	117	diff_cmd,
c983370e	118	path0[0], path1[0], path0[1], path1[1]);
be3cfa85 JH	119	next_at += snprintf(cmd+next_at, cmd_size-next_at,
	120	" %s ", diff_opts);
	121	next_at += snprintf(cmd+next_at, cmd_size-next_at,
2f978138 JH	122	diff_arg, input_name_sq[0], input_name_sq[1]);
2f978138 JH	123
c983370e JH	124	if (!path1[0][0])
	125	printf("Created: %s (mode:%s)\n", name, temp[1].mode);
	126	else if (!path1[1][0])
	127	printf("Deleted: %s\n", name);
	128	else if (strcmp(temp[0].mode, temp[1].mode))
	129	printf("Mode changed: %s (%s->%s)\n", name,
	130	temp[0].mode, temp[1].mode);
	131	fflush(NULL);
be3cfa85	132	execlp("/bin/sh","sh", "-c", cmd, NULL);
86436c28 JH	133	}
86436c28 JH	134
be3cfa85 JH	135	static void prepare_temp_file(const char *name,
	136	struct diff_tempfile *temp,
	137	struct diff_spec *one)
86436c28	138	{
be3cfa85 JH	139	static unsigned char null_sha1[20] = { 0, };
	140
	141	if (!one->file_valid) {
	142	not_a_valid_file:
532149d7 JH	143	/* A '-' entry produces this for file-2, and
	144	* a '+' entry produces this for file-1.
	145	*/
be3cfa85 JH	146	temp->name = "/dev/null";
	147	strcpy(temp->hex, ".");
	148	strcpy(temp->mode, ".");
86436c28 JH	149	return;
86436c28 JH	150	}
be3cfa85 JH	151
	152	if (one->sha1_valid &&
	153	!memcmp(one->u.sha1, null_sha1, sizeof(null_sha1))) {
	154	one->sha1_valid = 0;
	155	one->u.name = name;
	156	}
	157
	158	if (!one->sha1_valid) {
	159	struct stat st;
	160	temp->name = one->u.name;
	161	if (stat(temp->name, &st) < 0) {
	162	if (errno == ENOENT)
	163	goto not_a_valid_file;
	164	die("stat(%s): %s", temp->name, strerror(errno));
	165	}
532149d7	166	strcpy(temp->hex, sha1_to_hex(null_sha1));
be3cfa85 JH	167	sprintf(temp->mode, "%06o",
	168	S_IFREG \|ce_permissions(st.st_mode));
	169	}
	170	else {
	171	int fd;
	172	void *blob;
	173	char type[20];
	174	unsigned long size;
	175
	176	blob = read_sha1_file(one->u.sha1, type, &size);
	177	if (!blob \|\| strcmp(type, "blob"))
	178	die("unable to read blob object for %s (%s)",
	179	name, sha1_to_hex(one->u.sha1));
	180
	181	strcpy(temp->tmp_path, ".diff_XXXXXX");
	182	fd = mkstemp(temp->tmp_path);
	183	if (fd < 0)
	184	die("unable to create temp-file");
	185	if (write(fd, blob, size) != size)
	186	die("unable to write temp-file");
	187	close(fd);
	188	free(blob);
	189	temp->name = temp->tmp_path;
	190	strcpy(temp->hex, sha1_to_hex(one->u.sha1));
	191	temp->hex[40] = 0;
	192	sprintf(temp->mode, "%06o", one->mode);
	193	}
	194	}
	195
	196	static void remove_tempfile(void)
	197	{
	198	int i;
	199
	200	for (i = 0; i < 2; i++)
	201	if (diff_temp[i].name == diff_temp[i].tmp_path) {
	202	unlink(diff_temp[i].name);
	203	diff_temp[i].name = NULL;
	204	}
	205	}
	206
532149d7 JH	207	static void remove_tempfile_on_signal(int signo)
	208	{
	209	remove_tempfile();
	210	}
	211
be3cfa85 JH	212	/* An external diff command takes:
	213	*
	214	* diff-cmd name infile1 infile1-sha1 infile1-mode \
	215	* infile2 infile2-sha1 infile2-mode.
	216	*
	217	*/
	218	void run_external_diff(const char *name,
	219	struct diff_spec *one,
	220	struct diff_spec *two)
	221	{
	222	struct diff_tempfile *temp = diff_temp;
532149d7 JH	223	pid_t pid;
532149d7 JH	224	int status;
be3cfa85 JH	225	static int atexit_asked = 0;
be3cfa85 JH	226
77eb2720 JH	227	if (one && two) {
	228	prepare_temp_file(name, &temp[0], one);
	229	prepare_temp_file(name, &temp[1], two);
	230	if (! atexit_asked &&
	231	(temp[0].name == temp[0].tmp_path \|\|
	232	temp[1].name == temp[1].tmp_path)) {
	233	atexit_asked = 1;
	234	atexit(remove_tempfile);
	235	}
532149d7	236	signal(SIGINT, remove_tempfile_on_signal);
be3cfa85 JH	237	}
	238
	239	fflush(NULL);
	240	pid = fork();
	241	if (pid < 0)
	242	die("unable to fork");
	243	if (!pid) {
	244	const char *pgm = external_diff();
77eb2720 JH	245	if (pgm) {
	246	if (one && two)
	247	execlp(pgm, pgm,
	248	name,
	249	temp[0].name, temp[0].hex, temp[0].mode,
	250	temp[1].name, temp[1].hex, temp[1].mode,
	251	NULL);
	252	else
	253	execlp(pgm, pgm, name, NULL);
	254	}
be3cfa85 JH	255	/*
	256	* otherwise we use the built-in one.
	257	*/
77eb2720 JH	258	if (one && two)
	259	builtin_diff(name, temp);
	260	else
	261	printf("* Unmerged path %s\n", name);
be3cfa85 JH	262	exit(0);
be3cfa85 JH	263	}
6fa28064 JH	264	if (waitpid(pid, &status, 0) < 0 \|\|
	265	!WIFEXITED(status) \|\| WEXITSTATUS(status)) {
	266	/* Earlier we did not check the exit status because
532149d7	267	* diff exits non-zero if files are different, and
6fa28064 JH	268	* we are not interested in knowing that. It was a
	269	* mistake which made it harder to quit a diff-*
	270	* session that uses the git-apply-patch-script as
	271	* the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
	272	* should also exit non-zero only when it wants to
	273	* abort the entire diff-* session.
532149d7 JH	274	*/
532149d7 JH	275	remove_tempfile();
6fa28064 JH	276	fprintf(stderr, "external diff died, stopping at %s.\n", name);
6fa28064 JH	277	exit(1);
532149d7	278	}
be3cfa85 JH	279	remove_tempfile();
	280	}
	281
77eb2720 JH	282	void diff_addremove(int addremove, unsigned mode,
	283	const unsigned char *sha1,
	284	const char base, const char path)
be3cfa85	285	{
77eb2720	286	char concatpath[PATH_MAX];
be3cfa85 JH	287	struct diff_spec spec[2], one, two;
be3cfa85 JH	288
77eb2720 JH	289	memcpy(spec[0].u.sha1, sha1, 20);
77eb2720 JH	290	spec[0].mode = mode;
be3cfa85 JH	291	spec[0].sha1_valid = spec[0].file_valid = 1;
	292	spec[1].file_valid = 0;
	293
77eb2720	294	if (addremove == '+') {
be3cfa85 JH	295	one = spec + 1; two = spec;
	296	} else {
	297	one = spec; two = one + 1;
	298	}
77eb2720 JH	299
	300	if (path) {
	301	strcpy(concatpath, base);
77eb2720 JH	302	strcat(concatpath, path);
	303	}
	304	run_external_diff(path ? concatpath : base, one, two);
be3cfa85 JH	305	}
be3cfa85 JH	306
77eb2720 JH	307	void diff_change(unsigned old_mode, unsigned new_mode,
	308	const unsigned char *old_sha1,
	309	const unsigned char *new_sha1,
	310	const char base, const char path) {
	311	char concatpath[PATH_MAX];
	312	struct diff_spec spec[2];
	313
	314	memcpy(spec[0].u.sha1, old_sha1, 20);
	315	spec[0].mode = old_mode;
	316	memcpy(spec[1].u.sha1, new_sha1, 20);
	317	spec[1].mode = new_mode;
be3cfa85	318	spec[0].sha1_valid = spec[0].file_valid = 1;
77eb2720	319	spec[1].sha1_valid = spec[1].file_valid = 1;
be3cfa85	320
77eb2720 JH	321	if (path) {
77eb2720 JH	322	strcpy(concatpath, base);
77eb2720	323	strcat(concatpath, path);
be3cfa85	324	}
77eb2720 JH	325	run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
77eb2720 JH	326	}
be3cfa85	327
77eb2720 JH	328	void diff_unmerge(const char *path)
	329	{
	330	run_external_diff(path, NULL, NULL);
86436c28	331	}