[thirdparty/git.git] / tree-diff.c

/*
 * Helper functions for tree diff generation
 */
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
#include "tree.h"

static void show_entry(struct diff_options *opt, const char *prefix,
		       struct tree_desc *desc, struct strbuf *base);

static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
			      struct strbuf *base, struct diff_options *opt)
{
	unsigned mode1, mode2;
	const char *path1, *path2;
	const unsigned char *sha1, *sha2;
	int cmp, pathlen1, pathlen2;
	int old_baselen = base->len;

	sha1 = tree_entry_extract(t1, &path1, &mode1);
	sha2 = tree_entry_extract(t2, &path2, &mode2);

	pathlen1 = tree_entry_len(&t1->entry);
	pathlen2 = tree_entry_len(&t2->entry);
	cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
	if (cmp < 0) {
		show_entry(opt, "-", t1, base);
		return -1;
	}
	if (cmp > 0) {
		show_entry(opt, "+", t2, base);
		return 1;
	}
	if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
		return 0;

	/*
	 * If the filemode has changed to/from a directory from/to a regular
	 * file, we need to consider it a remove and an add.
	 */
	if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
		show_entry(opt, "-", t1, base);
		show_entry(opt, "+", t2, base);
		return 0;
	}

	strbuf_add(base, path1, pathlen1);
	if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
		if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
			opt->change(opt, mode1, mode2,
				    sha1, sha2, 1, 1, base->buf, 0, 0);
		}
		strbuf_addch(base, '/');
		diff_tree_sha1(sha1, sha2, base->buf, opt);
	} else {
		opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
	}
	strbuf_setlen(base, old_baselen);
	return 0;
}

/* A whole sub-tree went away or appeared */
static void show_tree(struct diff_options *opt, const char *prefix,
		      struct tree_desc *desc, struct strbuf *base)
{
	enum interesting match = entry_not_interesting;
	for (; desc->size; update_tree_entry(desc)) {
		if (match != all_entries_interesting) {
			match = tree_entry_interesting(&desc->entry, base, 0,
						       &opt->pathspec);
			if (match == all_entries_not_interesting)
				break;
			if (match == entry_not_interesting)
				continue;
		}
		show_entry(opt, prefix, desc, base);
	}
}

/* A file entry went away or appeared */
static void show_entry(struct diff_options *opt, const char *prefix,
		       struct tree_desc *desc, struct strbuf *base)
{
	unsigned mode;
	const char *path;
	const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
	int pathlen = tree_entry_len(&desc->entry);
	int old_baselen = base->len;

	strbuf_add(base, path, pathlen);
	if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
		enum object_type type;
		struct tree_desc inner;
		void *tree;
		unsigned long size;

		tree = read_sha1_file(sha1, &type, &size);
		if (!tree || type != OBJ_TREE)
			die("corrupt tree sha %s", sha1_to_hex(sha1));

		if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
			opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);

		strbuf_addch(base, '/');

		init_tree_desc(&inner, tree, size);
		show_tree(opt, prefix, &inner, base);
		free(tree);
	} else
		opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);

	strbuf_setlen(base, old_baselen);
}

static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
			       struct diff_options *opt,
			       enum interesting *match)
{
	while (t->size) {
		*match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
		if (*match) {
			if (*match == all_entries_not_interesting)
				t->size = 0;
			break;
		}
		update_tree_entry(t);
	}
}

int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
	      const char *base_str, struct diff_options *opt)
{
	struct strbuf base;
	int baselen = strlen(base_str);
	enum interesting t1_match = entry_not_interesting;
	enum interesting t2_match = entry_not_interesting;

	/* Enable recursion indefinitely */
	opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);

	strbuf_init(&base, PATH_MAX);
	strbuf_add(&base, base_str, baselen);

	for (;;) {
		if (diff_can_quit_early(opt))
			break;
		if (opt->pathspec.nr) {
			skip_uninteresting(t1, &base, opt, &t1_match);
			skip_uninteresting(t2, &base, opt, &t2_match);
		}
		if (!t1->size) {
			if (!t2->size)
				break;
			show_entry(opt, "+", t2, &base);
			update_tree_entry(t2);
			continue;
		}
		if (!t2->size) {
			show_entry(opt, "-", t1, &base);
			update_tree_entry(t1);
			continue;
		}
		switch (compare_tree_entry(t1, t2, &base, opt)) {
		case -1:
			update_tree_entry(t1);
			continue;
		case 0:
			update_tree_entry(t1);
			/* Fallthrough */
		case 1:
			update_tree_entry(t2);
			continue;
		}
		die("git diff-tree: internal error");
	}

	strbuf_release(&base);
	return 0;
}

/*
 * Does it look like the resulting diff might be due to a rename?
 *  - single entry
 *  - not a valid previous file
 */
static inline int diff_might_be_rename(void)
{
	return diff_queued_diff.nr == 1 &&
		!DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
}

static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
{
	struct diff_options diff_opts;
	struct diff_queue_struct *q = &diff_queued_diff;
	struct diff_filepair *choice;
	int i;

	/*
	 * follow-rename code is very specific, we need exactly one
	 * path. Magic that matches more than one path is not
	 * supported.
	 */
	GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP);
#if 0
	/*
	 * We should reject wildcards as well. Unfortunately we
	 * haven't got a reliable way to detect that 'foo\*bar' in
	 * fact has no wildcards. nowildcard_len is merely a hint for
	 * optimization. Let it slip for now until wildmatch is taught
	 * about dry-run mode and returns wildcard info.
	 */
	if (opt->pathspec.has_wildcard)
		die("BUG:%s:%d: wildcards are not supported",
		    __FILE__, __LINE__);
#endif

	/* Remove the file creation entry from the diff queue, and remember it */
	choice = q->queue[0];
	q->nr = 0;

	diff_setup(&diff_opts);
	DIFF_OPT_SET(&diff_opts, RECURSIVE);
	DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_opts.single_follow = opt->pathspec.raw[0];
	diff_opts.break_opt = opt->break_opt;
	diff_opts.rename_score = opt->rename_score;
	diff_setup_done(&diff_opts);
	diff_tree(t1, t2, base, &diff_opts);
	diffcore_std(&diff_opts);
	free_pathspec(&diff_opts.pathspec);

	/* Go through the new set of filepairing, and see if we find a more interesting one */
	opt->found_follow = 0;
	for (i = 0; i < q->nr; i++) {
		struct diff_filepair *p = q->queue[i];

		/*
		 * Found a source? Not only do we use that for the new
		 * diff_queued_diff, we will also use that as the path in
		 * the future!
		 */
		if ((p->status == 'R' || p->status == 'C') &&
		    !strcmp(p->two->path, opt->pathspec.raw[0])) {
			const char *path[2];

			/* Switch the file-pairs around */
			q->queue[i] = choice;
			choice = p;

			/* Update the path we use from now on.. */
			path[0] = p->one->path;
			path[1] = NULL;
			free_pathspec(&opt->pathspec);
			parse_pathspec(&opt->pathspec, PATHSPEC_ALL_MAGIC, 0, "", path);

			/*
			 * The caller expects us to return a set of vanilla
			 * filepairs to let a later call to diffcore_std()
			 * it makes to sort the renames out (among other
			 * things), but we already have found renames
			 * ourselves; signal diffcore_std() not to muck with
			 * rename information.
			 */
			opt->found_follow = 1;
			break;
		}
	}

	/*
	 * Then, discard all the non-relevant file pairs...
	 */
	for (i = 0; i < q->nr; i++) {
		struct diff_filepair *p = q->queue[i];
		diff_free_filepair(p);
	}

	/*
	 * .. and re-instate the one we want (which might be either the
	 * original one, or the rename/copy we found)
	 */
	q->queue[0] = choice;
	q->nr = 1;
}

int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
{
	void *tree1, *tree2;
	struct tree_desc t1, t2;
	unsigned long size1, size2;
	int retval;

	tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
	if (!tree1)
		die("unable to read source tree (%s)", sha1_to_hex(old));
	tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
	if (!tree2)
		die("unable to read destination tree (%s)", sha1_to_hex(new));
	init_tree_desc(&t1, tree1, size1);
	init_tree_desc(&t2, tree2, size2);
	retval = diff_tree(&t1, &t2, base, opt);
	if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
		init_tree_desc(&t1, tree1, size1);
		init_tree_desc(&t2, tree2, size2);
		try_to_follow_renames(&t1, &t2, base, opt);
	}
	free(tree1);
	free(tree2);
	return retval;
}

int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
{
	int retval;
	void *tree;
	unsigned long size;
	struct tree_desc empty, real;

	tree = read_object_with_reference(new, tree_type, &size, NULL);
	if (!tree)
		die("unable to read root tree (%s)", sha1_to_hex(new));
	init_tree_desc(&real, tree, size);

	init_tree_desc(&empty, "", 0);
	retval = diff_tree(&empty, &real, base, opt);
	free(tree);
	return retval;
}
Commit	Line	Data
ac1b3d12 LT	1	/*
	2	* Helper functions for tree diff generation
	3	*/
	4	#include "cache.h"
	5	#include "diff.h"
750f7b66	6	#include "diffcore.h"
8e440259	7	#include "tree.h"
ac1b3d12	8
48932677 NTND	9	static void show_entry(struct diff_options opt, const char prefix,
48932677 NTND	10	struct tree_desc desc, struct strbuf base);
ac1b3d12	11
48932677 NTND	12	static int compare_tree_entry(struct tree_desc t1, struct tree_desc t2,
48932677 NTND	13	struct strbuf base, struct diff_options opt)
ac1b3d12 LT	14	{
	15	unsigned mode1, mode2;
	16	const char path1, path2;
	17	const unsigned char sha1, sha2;
	18	int cmp, pathlen1, pathlen2;
48932677	19	int old_baselen = base->len;
ac1b3d12	20
50f9a858 LT	21	sha1 = tree_entry_extract(t1, &path1, &mode1);
50f9a858 LT	22	sha2 = tree_entry_extract(t2, &path2, &mode2);
ac1b3d12	23
0de16337 NTND	24	pathlen1 = tree_entry_len(&t1->entry);
0de16337 NTND	25	pathlen2 = tree_entry_len(&t2->entry);
ac1b3d12 LT	26	cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
ac1b3d12 LT	27	if (cmp < 0) {
48932677	28	show_entry(opt, "-", t1, base);
ac1b3d12 LT	29	return -1;
	30	}
	31	if (cmp > 0) {
48932677	32	show_entry(opt, "+", t2, base);
ac1b3d12 LT	33	return 1;
ac1b3d12 LT	34	}
8f67f8ae	35	if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
ac1b3d12 LT	36	return 0;
	37
	38	/*
	39	* If the filemode has changed to/from a directory from/to a regular
	40	* file, we need to consider it a remove and an add.
	41	*/
	42	if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
48932677 NTND	43	show_entry(opt, "-", t1, base);
48932677 NTND	44	show_entry(opt, "+", t2, base);
ac1b3d12 LT	45	return 0;
	46	}
	47
48932677	48	strbuf_add(base, path1, pathlen1);
8f67f8ae	49	if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
fd55a19e	50	if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
ac1b3d12	51	opt->change(opt, mode1, mode2,
e5450100	52	sha1, sha2, 1, 1, base->buf, 0, 0);
fd55a19e	53	}
48932677	54	strbuf_addch(base, '/');
c0aa335c	55	diff_tree_sha1(sha1, sha2, base->buf, opt);
48932677	56	} else {
e5450100	57	opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
ac1b3d12	58	}
48932677	59	strbuf_setlen(base, old_baselen);
ac1b3d12 LT	60	return 0;
	61	}
	62
ac1b3d12	63	/* A whole sub-tree went away or appeared */
48932677 NTND	64	static void show_tree(struct diff_options opt, const char prefix,
48932677 NTND	65	struct tree_desc desc, struct strbuf base)
ac1b3d12	66	{
d688cf07	67	enum interesting match = entry_not_interesting;
97d0b74a	68	for (; desc->size; update_tree_entry(desc)) {
d688cf07	69	if (match != all_entries_interesting) {
97d0b74a NTND	70	match = tree_entry_interesting(&desc->entry, base, 0,
97d0b74a NTND	71	&opt->pathspec);
d688cf07	72	if (match == all_entries_not_interesting)
97d0b74a	73	break;
d688cf07	74	if (match == entry_not_interesting)
97d0b74a	75	continue;
1d848f64	76	}
97d0b74a	77	show_entry(opt, prefix, desc, base);
ac1b3d12 LT	78	}
	79	}
	80
	81	/* A file entry went away or appeared */
48932677 NTND	82	static void show_entry(struct diff_options opt, const char prefix,
48932677 NTND	83	struct tree_desc desc, struct strbuf base)
ac1b3d12 LT	84	{
	85	unsigned mode;
	86	const char *path;
50f9a858	87	const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
0de16337	88	int pathlen = tree_entry_len(&desc->entry);
48932677	89	int old_baselen = base->len;
ac1b3d12	90
48932677	91	strbuf_add(base, path, pathlen);
8f67f8ae	92	if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
21666f1a	93	enum object_type type;
ac1b3d12 LT	94	struct tree_desc inner;
ac1b3d12 LT	95	void *tree;
6fda5e51	96	unsigned long size;
ac1b3d12	97
6fda5e51	98	tree = read_sha1_file(sha1, &type, &size);
21666f1a	99	if (!tree \|\| type != OBJ_TREE)
ac1b3d12 LT	100	die("corrupt tree sha %s", sha1_to_hex(sha1));
ac1b3d12 LT	101
48932677	102	if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
e5450100	103	opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);
df533f34	104
48932677	105	strbuf_addch(base, '/');
ac1b3d12	106
48932677 NTND	107	init_tree_desc(&inner, tree, size);
48932677 NTND	108	show_tree(opt, prefix, &inner, base);
ac1b3d12	109	free(tree);
48932677	110	} else
e5450100	111	opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);
48932677 NTND	112
48932677 NTND	113	strbuf_setlen(base, old_baselen);
ac1b3d12 LT	114	}
ac1b3d12 LT	115
48932677	116	static void skip_uninteresting(struct tree_desc t, struct strbuf base,
d688cf07 NTND	117	struct diff_options *opt,
d688cf07 NTND	118	enum interesting *match)
5d865017 LT	119	{
5d865017 LT	120	while (t->size) {
97d0b74a NTND	121	*match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
97d0b74a NTND	122	if (*match) {
d688cf07	123	if (*match == all_entries_not_interesting)
97d0b74a NTND	124	t->size = 0;
97d0b74a NTND	125	break;
5d865017	126	}
97d0b74a	127	update_tree_entry(t);
5d865017 LT	128	}
	129	}
	130
48932677 NTND	131	int diff_tree(struct tree_desc t1, struct tree_desc t2,
48932677 NTND	132	const char base_str, struct diff_options opt)
ac1b3d12	133	{
48932677 NTND	134	struct strbuf base;
48932677 NTND	135	int baselen = strlen(base_str);
d688cf07 NTND	136	enum interesting t1_match = entry_not_interesting;
d688cf07 NTND	137	enum interesting t2_match = entry_not_interesting;
304de2d2	138
bc96cc87 NTND	139	/* Enable recursion indefinitely */
bc96cc87 NTND	140	opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
bc96cc87	141
48932677 NTND	142	strbuf_init(&base, PATH_MAX);
	143	strbuf_add(&base, base_str, baselen);
	144
5d865017	145	for (;;) {
28b9264d	146	if (diff_can_quit_early(opt))
822cac01	147	break;
66f13625	148	if (opt->pathspec.nr) {
97d0b74a NTND	149	skip_uninteresting(t1, &base, opt, &t1_match);
97d0b74a NTND	150	skip_uninteresting(t2, &base, opt, &t2_match);
ac1b3d12 LT	151	}
ac1b3d12 LT	152	if (!t1->size) {
5d865017 LT	153	if (!t2->size)
5d865017 LT	154	break;
48932677	155	show_entry(opt, "+", t2, &base);
ac1b3d12 LT	156	update_tree_entry(t2);
	157	continue;
	158	}
	159	if (!t2->size) {
48932677	160	show_entry(opt, "-", t1, &base);
ac1b3d12 LT	161	update_tree_entry(t1);
	162	continue;
	163	}
48932677	164	switch (compare_tree_entry(t1, t2, &base, opt)) {
ac1b3d12 LT	165	case -1:
	166	update_tree_entry(t1);
	167	continue;
	168	case 0:
	169	update_tree_entry(t1);
	170	/* Fallthrough */
	171	case 1:
	172	update_tree_entry(t2);
	173	continue;
	174	}
7e44c935	175	die("git diff-tree: internal error");
ac1b3d12	176	}
48932677 NTND	177
48932677 NTND	178	strbuf_release(&base);
ac1b3d12 LT	179	return 0;
	180	}
	181
750f7b66 LT	182	/*
	183	* Does it look like the resulting diff might be due to a rename?
	184	* - single entry
	185	* - not a valid previous file
	186	*/
	187	static inline int diff_might_be_rename(void)
	188	{
	189	return diff_queued_diff.nr == 1 &&
	190	!DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
	191	}
	192
	193	static void try_to_follow_renames(struct tree_desc t1, struct tree_desc t2, const char base, struct diff_options opt)
	194	{
	195	struct diff_options diff_opts;
9f38e1ef LT	196	struct diff_queue_struct *q = &diff_queued_diff;
9f38e1ef LT	197	struct diff_filepair *choice;
750f7b66 LT	198	int i;
750f7b66 LT	199
8f4f8f45 NTND	200	/*
	201	* follow-rename code is very specific, we need exactly one
	202	* path. Magic that matches more than one path is not
	203	* supported.
	204	*/
	205	GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP);
	206	#if 0
	207	/*
	208	* We should reject wildcards as well. Unfortunately we
	209	* haven't got a reliable way to detect that 'foo\*bar' in
	210	* fact has no wildcards. nowildcard_len is merely a hint for
	211	* optimization. Let it slip for now until wildmatch is taught
	212	* about dry-run mode and returns wildcard info.
	213	*/
	214	if (opt->pathspec.has_wildcard)
	215	die("BUG:%s:%d: wildcards are not supported",
	216	__FILE__, __LINE__);
	217	#endif
	218
9f38e1ef LT	219	/* Remove the file creation entry from the diff queue, and remember it */
	220	choice = q->queue[0];
	221	q->nr = 0;
	222
750f7b66	223	diff_setup(&diff_opts);
8f67f8ae	224	DIFF_OPT_SET(&diff_opts, RECURSIVE);
0cdca133	225	DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
750f7b66	226	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
66f13625	227	diff_opts.single_follow = opt->pathspec.raw[0];
6dd4b66f	228	diff_opts.break_opt = opt->break_opt;
dd98d88b	229	diff_opts.rename_score = opt->rename_score;
28452655	230	diff_setup_done(&diff_opts);
750f7b66 LT	231	diff_tree(t1, t2, base, &diff_opts);
750f7b66 LT	232	diffcore_std(&diff_opts);
bd1928df	233	free_pathspec(&diff_opts.pathspec);
750f7b66	234
9f38e1ef	235	/* Go through the new set of filepairing, and see if we find a more interesting one */
44c48a90	236	opt->found_follow = 0;
9f38e1ef LT	237	for (i = 0; i < q->nr; i++) {
9f38e1ef LT	238	struct diff_filepair *p = q->queue[i];
750f7b66 LT	239
	240	/*
	241	* Found a source? Not only do we use that for the new
9f38e1ef	242	* diff_queued_diff, we will also use that as the path in
750f7b66 LT	243	* the future!
750f7b66 LT	244	*/
66f13625 NTND	245	if ((p->status == 'R' \|\| p->status == 'C') &&
66f13625 NTND	246	!strcmp(p->two->path, opt->pathspec.raw[0])) {
9a087274 NTND	247	const char *path[2];
9a087274 NTND	248
9f38e1ef LT	249	/* Switch the file-pairs around */
	250	q->queue[i] = choice;
	251	choice = p;
	252
	253	/* Update the path we use from now on.. */
9a087274 NTND	254	path[0] = p->one->path;
9a087274 NTND	255	path[1] = NULL;
bd1928df	256	free_pathspec(&opt->pathspec);
9a087274	257	parse_pathspec(&opt->pathspec, PATHSPEC_ALL_MAGIC, 0, "", path);
44c48a90 JH	258
	259	/*
	260	* The caller expects us to return a set of vanilla
	261	* filepairs to let a later call to diffcore_std()
	262	* it makes to sort the renames out (among other
	263	* things), but we already have found renames
	264	* ourselves; signal diffcore_std() not to muck with
	265	* rename information.
	266	*/
	267	opt->found_follow = 1;
750f7b66 LT	268	break;
	269	}
	270	}
	271
	272	/*
3ea3c215	273	* Then, discard all the non-relevant file pairs...
9f38e1ef LT	274	*/
	275	for (i = 0; i < q->nr; i++) {
	276	struct diff_filepair *p = q->queue[i];
	277	diff_free_filepair(p);
	278	}
	279
	280	/*
	281	* .. and re-instate the one we want (which might be either the
	282	* original one, or the rename/copy we found)
750f7b66	283	*/
9f38e1ef LT	284	q->queue[0] = choice;
9f38e1ef LT	285	q->nr = 1;
750f7b66 LT	286	}
750f7b66 LT	287
ac1b3d12 LT	288	int diff_tree_sha1(const unsigned char old, const unsigned char new, const char base, struct diff_options opt)
	289	{
	290	void tree1, tree2;
	291	struct tree_desc t1, t2;
6fda5e51	292	unsigned long size1, size2;
ac1b3d12 LT	293	int retval;
ac1b3d12 LT	294
6fda5e51	295	tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
ac1b3d12 LT	296	if (!tree1)
ac1b3d12 LT	297	die("unable to read source tree (%s)", sha1_to_hex(old));
6fda5e51	298	tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
ac1b3d12 LT	299	if (!tree2)
ac1b3d12 LT	300	die("unable to read destination tree (%s)", sha1_to_hex(new));
6fda5e51 LT	301	init_tree_desc(&t1, tree1, size1);
6fda5e51 LT	302	init_tree_desc(&t2, tree2, size2);
ac1b3d12	303	retval = diff_tree(&t1, &t2, base, opt);
39f75d26	304	if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
750f7b66 LT	305	init_tree_desc(&t1, tree1, size1);
	306	init_tree_desc(&t2, tree2, size2);
	307	try_to_follow_renames(&t1, &t2, base, opt);
	308	}
ac1b3d12 LT	309	free(tree1);
	310	free(tree2);
	311	return retval;
	312	}
	313
2b60356d RS	314	int diff_root_tree_sha1(const unsigned char new, const char base, struct diff_options *opt)
	315	{
	316	int retval;
	317	void *tree;
6fda5e51	318	unsigned long size;
2b60356d RS	319	struct tree_desc empty, real;
2b60356d RS	320
6fda5e51	321	tree = read_object_with_reference(new, tree_type, &size, NULL);
2b60356d RS	322	if (!tree)
2b60356d RS	323	die("unable to read root tree (%s)", sha1_to_hex(new));
6fda5e51	324	init_tree_desc(&real, tree, size);
2b60356d	325
6fda5e51	326	init_tree_desc(&empty, "", 0);
2b60356d RS	327	retval = diff_tree(&empty, &real, base, opt);
	328	free(tree);
	329	return retval;
	330	}