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

#include "cache.h"
#include "tree.h"
#include "cache-tree.h"

#define DEBUG 0

struct cache_tree *cache_tree(void)
{
	struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
	it->entry_count = -1;
	return it;
}

void cache_tree_free(struct cache_tree **it_p)
{
	int i;
	struct cache_tree *it = *it_p;

	if (!it)
		return;
	for (i = 0; i < it->subtree_nr; i++)
		if (it->down[i])
			cache_tree_free(&it->down[i]->cache_tree);
	free(it->down);
	free(it);
	*it_p = NULL;
}

static int subtree_name_cmp(const char *one, int onelen,
			    const char *two, int twolen)
{
	if (onelen < twolen)
		return -1;
	if (twolen < onelen)
		return 1;
	return memcmp(one, two, onelen);
}

static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
{
	struct cache_tree_sub **down = it->down;
	int lo, hi;
	lo = 0;
	hi = it->subtree_nr;
	while (lo < hi) {
		int mi = (lo + hi) / 2;
		struct cache_tree_sub *mdl = down[mi];
		int cmp = subtree_name_cmp(path, pathlen,
					   mdl->name, mdl->namelen);
		if (!cmp)
			return mi;
		if (cmp < 0)
			hi = mi;
		else
			lo = mi + 1;
	}
	return -lo-1;
}

static struct cache_tree_sub *find_subtree(struct cache_tree *it,
					   const char *path,
					   int pathlen,
					   int create)
{
	struct cache_tree_sub *down;
	int pos = subtree_pos(it, path, pathlen);
	if (0 <= pos)
		return it->down[pos];
	if (!create)
		return NULL;

	pos = -pos-1;
	if (it->subtree_alloc <= it->subtree_nr) {
		it->subtree_alloc = alloc_nr(it->subtree_alloc);
		it->down = xrealloc(it->down, it->subtree_alloc *
				    sizeof(*it->down));
	}
	it->subtree_nr++;

	down = xmalloc(sizeof(*down) + pathlen + 1);
	down->cache_tree = NULL;
	down->namelen = pathlen;
	memcpy(down->name, path, pathlen);
	down->name[pathlen] = 0;

	if (pos < it->subtree_nr)
		memmove(it->down + pos + 1,
			it->down + pos,
			sizeof(down) * (it->subtree_nr - pos - 1));
	it->down[pos] = down;
	return down;
}

struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
{
	int pathlen = strlen(path);
	return find_subtree(it, path, pathlen, 1);
}

void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
{
	/* a/b/c
	 * ==> invalidate self
	 * ==> find "a", have it invalidate "b/c"
	 * a
	 * ==> invalidate self
	 * ==> if "a" exists as a subtree, remove it.
	 */
	const char *slash;
	int namelen;
	struct cache_tree_sub *down;

#if DEBUG
	fprintf(stderr, "cache-tree invalidate <%s>\n", path);
#endif

	if (!it)
		return;
	slash = strchr(path, '/');
	it->entry_count = -1;
	if (!slash) {
		int pos;
		namelen = strlen(path);
		pos = subtree_pos(it, path, namelen);
		if (0 <= pos) {
			cache_tree_free(&it->down[pos]->cache_tree);
			free(it->down[pos]);
			/* 0 1 2 3 4 5
			 *       ^     ^subtree_nr = 6
			 *       pos
			 * move 4 and 5 up one place (2 entries)
			 * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
			 */
			memmove(it->down+pos, it->down+pos+1,
				sizeof(struct cache_tree_sub *) *
				(it->subtree_nr - pos - 1));
			it->subtree_nr--;
		}
		return;
	}
	namelen = slash - path;
	down = find_subtree(it, path, namelen, 0);
	if (down)
		cache_tree_invalidate_path(down->cache_tree, slash + 1);
}

static int verify_cache(struct cache_entry **cache,
			int entries)
{
	int i, funny;

	/* Verify that the tree is merged */
	funny = 0;
	for (i = 0; i < entries; i++) {
		struct cache_entry *ce = cache[i];
		if (ce_stage(ce)) {
			if (10 < ++funny) {
				fprintf(stderr, "...\n");
				break;
			}
			fprintf(stderr, "%s: unmerged (%s)\n",
				ce->name, sha1_to_hex(ce->sha1));
		}
	}
	if (funny)
		return -1;

	/* Also verify that the cache does not have path and path/file
	 * at the same time.  At this point we know the cache has only
	 * stage 0 entries.
	 */
	funny = 0;
	for (i = 0; i < entries - 1; i++) {
		/* path/file always comes after path because of the way
		 * the cache is sorted.  Also path can appear only once,
		 * which means conflicting one would immediately follow.
		 */
		const char *this_name = cache[i]->name;
		const char *next_name = cache[i+1]->name;
		int this_len = strlen(this_name);
		if (this_len < strlen(next_name) &&
		    strncmp(this_name, next_name, this_len) == 0 &&
		    next_name[this_len] == '/') {
			if (10 < ++funny) {
				fprintf(stderr, "...\n");
				break;
			}
			fprintf(stderr, "You have both %s and %s\n",
				this_name, next_name);
		}
	}
	if (funny)
		return -1;
	return 0;
}

static void discard_unused_subtrees(struct cache_tree *it)
{
	struct cache_tree_sub **down = it->down;
	int nr = it->subtree_nr;
	int dst, src;
	for (dst = src = 0; src < nr; src++) {
		struct cache_tree_sub *s = down[src];
		if (s->used)
			down[dst++] = s;
		else {
			cache_tree_free(&s->cache_tree);
			free(s);
			it->subtree_nr--;
		}
	}
}

int cache_tree_fully_valid(struct cache_tree *it)
{
	int i;
	if (!it)
		return 0;
	if (it->entry_count < 0 || !has_sha1_file(it->sha1))
		return 0;
	for (i = 0; i < it->subtree_nr; i++) {
		if (!cache_tree_fully_valid(it->down[i]->cache_tree))
			return 0;
	}
	return 1;
}

static int update_one(struct cache_tree *it,
		      struct cache_entry **cache,
		      int entries,
		      const char *base,
		      int baselen,
		      int missing_ok,
		      int dryrun)
{
	unsigned long size, offset;
	char *buffer;
	int i;

	if (0 <= it->entry_count && has_sha1_file(it->sha1))
		return it->entry_count;

	/*
	 * We first scan for subtrees and update them; we start by
	 * marking existing subtrees -- the ones that are unmarked
	 * should not be in the result.
	 */
	for (i = 0; i < it->subtree_nr; i++)
		it->down[i]->used = 0;

	/*
	 * Find the subtrees and update them.
	 */
	for (i = 0; i < entries; i++) {
		struct cache_entry *ce = cache[i];
		struct cache_tree_sub *sub;
		const char *path, *slash;
		int pathlen, sublen, subcnt;

		path = ce->name;
		pathlen = ce_namelen(ce);
		if (pathlen <= baselen || memcmp(base, path, baselen))
			break; /* at the end of this level */

		slash = strchr(path + baselen, '/');
		if (!slash)
			continue;
		/*
		 * a/bbb/c (base = a/, slash = /c)
		 * ==>
		 * path+baselen = bbb/c, sublen = 3
		 */
		sublen = slash - (path + baselen);
		sub = find_subtree(it, path + baselen, sublen, 1);
		if (!sub->cache_tree)
			sub->cache_tree = cache_tree();
		subcnt = update_one(sub->cache_tree,
				    cache + i, entries - i,
				    path,
				    baselen + sublen + 1,
				    missing_ok,
				    dryrun);
		i += subcnt - 1;
		sub->used = 1;
	}

	discard_unused_subtrees(it);

	/*
	 * Then write out the tree object for this level.
	 */
	size = 8192;
	buffer = xmalloc(size);
	offset = 0;

	for (i = 0; i < entries; i++) {
		struct cache_entry *ce = cache[i];
		struct cache_tree_sub *sub;
		const char *path, *slash;
		int pathlen, entlen;
		const unsigned char *sha1;
		unsigned mode;

		path = ce->name;
		pathlen = ce_namelen(ce);
		if (pathlen <= baselen || memcmp(base, path, baselen))
			break; /* at the end of this level */

		slash = strchr(path + baselen, '/');
		if (slash) {
			entlen = slash - (path + baselen);
			sub = find_subtree(it, path + baselen, entlen, 0);
			if (!sub)
				die("cache-tree.c: '%.*s' in '%s' not found",
				    entlen, path + baselen, path);
			i += sub->cache_tree->entry_count - 1;
			sha1 = sub->cache_tree->sha1;
			mode = S_IFDIR;
		}
		else {
			sha1 = ce->sha1;
			mode = ntohl(ce->ce_mode);
			entlen = pathlen - baselen;
		}
		if (!missing_ok && !has_sha1_file(sha1))
			return error("invalid object %s", sha1_to_hex(sha1));

		if (!ce->ce_mode)
			continue; /* entry being removed */

		if (size < offset + entlen + 100) {
			size = alloc_nr(offset + entlen + 100);
			buffer = xrealloc(buffer, size);
		}
		offset += sprintf(buffer + offset,
				  "%o %.*s", mode, entlen, path + baselen);
		buffer[offset++] = 0;
		hashcpy((unsigned char*)buffer + offset, sha1);
		offset += 20;

#if DEBUG
		fprintf(stderr, "cache-tree update-one %o %.*s\n",
			mode, entlen, path + baselen);
#endif
	}

	if (dryrun)
		hash_sha1_file(buffer, offset, tree_type, it->sha1);
	else
		write_sha1_file(buffer, offset, tree_type, it->sha1);
	free(buffer);
	it->entry_count = i;
#if DEBUG
	fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
		it->entry_count, it->subtree_nr,
		sha1_to_hex(it->sha1));
#endif
	return i;
}

int cache_tree_update(struct cache_tree *it,
		      struct cache_entry **cache,
		      int entries,
		      int missing_ok,
		      int dryrun)
{
	int i;
	i = verify_cache(cache, entries);
	if (i)
		return i;
	i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
	if (i < 0)
		return i;
	return 0;
}

static void *write_one(struct cache_tree *it,
		       char *path,
		       int pathlen,
		       char *buffer,
		       unsigned long *size,
		       unsigned long *offset)
{
	int i;

	/* One "cache-tree" entry consists of the following:
	 * path (NUL terminated)
	 * entry_count, subtree_nr ("%d %d\n")
	 * tree-sha1 (missing if invalid)
	 * subtree_nr "cache-tree" entries for subtrees.
	 */
	if (*size < *offset + pathlen + 100) {
		*size = alloc_nr(*offset + pathlen + 100);
		buffer = xrealloc(buffer, *size);
	}
	*offset += sprintf(buffer + *offset, "%.*s%c%d %d\n",
			   pathlen, path, 0,
			   it->entry_count, it->subtree_nr);

#if DEBUG
	if (0 <= it->entry_count)
		fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
			pathlen, path, it->entry_count, it->subtree_nr,
			sha1_to_hex(it->sha1));
	else
		fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
			pathlen, path, it->subtree_nr);
#endif

	if (0 <= it->entry_count) {
		hashcpy((unsigned char*)buffer + *offset, it->sha1);
		*offset += 20;
	}
	for (i = 0; i < it->subtree_nr; i++) {
		struct cache_tree_sub *down = it->down[i];
		if (i) {
			struct cache_tree_sub *prev = it->down[i-1];
			if (subtree_name_cmp(down->name, down->namelen,
					     prev->name, prev->namelen) <= 0)
				die("fatal - unsorted cache subtree");
		}
		buffer = write_one(down->cache_tree, down->name, down->namelen,
				   buffer, size, offset);
	}
	return buffer;
}

void *cache_tree_write(struct cache_tree *root, unsigned long *size_p)
{
	char path[PATH_MAX];
	unsigned long size = 8192;
	char *buffer = xmalloc(size);

	*size_p = 0;
	path[0] = 0;
	return write_one(root, path, 0, buffer, &size, size_p);
}

static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
{
	const char *buf = *buffer;
	unsigned long size = *size_p;
	const char *cp;
	char *ep;
	struct cache_tree *it;
	int i, subtree_nr;

	it = NULL;
	/* skip name, but make sure name exists */
	while (size && *buf) {
		size--;
		buf++;
	}
	if (!size)
		goto free_return;
	buf++; size--;
	it = cache_tree();

	cp = buf;
	it->entry_count = strtol(cp, &ep, 10);
	if (cp == ep)
		goto free_return;
	cp = ep;
	subtree_nr = strtol(cp, &ep, 10);
	if (cp == ep)
		goto free_return;
	while (size && *buf && *buf != '\n') {
		size--;
		buf++;
	}
	if (!size)
		goto free_return;
	buf++; size--;
	if (0 <= it->entry_count) {
		if (size < 20)
			goto free_return;
		hashcpy(it->sha1, (unsigned char*)buf);
		buf += 20;
		size -= 20;
	}

#if DEBUG
	if (0 <= it->entry_count)
		fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
			*buffer, it->entry_count, subtree_nr,
			sha1_to_hex(it->sha1));
	else
		fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
			*buffer, subtree_nr);
#endif

	/*
	 * Just a heuristic -- we do not add directories that often but
	 * we do not want to have to extend it immediately when we do,
	 * hence +2.
	 */
	it->subtree_alloc = subtree_nr + 2;
	it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
	for (i = 0; i < subtree_nr; i++) {
		/* read each subtree */
		struct cache_tree *sub;
		struct cache_tree_sub *subtree;
		const char *name = buf;

		sub = read_one(&buf, &size);
		if (!sub)
			goto free_return;
		subtree = cache_tree_sub(it, name);
		subtree->cache_tree = sub;
	}
	if (subtree_nr != it->subtree_nr)
		die("cache-tree: internal error");
	*buffer = buf;
	*size_p = size;
	return it;

 free_return:
	cache_tree_free(&it);
	return NULL;
}

struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
{
	if (buffer[0])
		return NULL; /* not the whole tree */
	return read_one(&buffer, &size);
}

struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
{
	while (*path) {
		const char *slash;
		struct cache_tree_sub *sub;

		slash = strchr(path, '/');
		if (!slash)
			slash = path + strlen(path);
		/* between path and slash is the name of the
		 * subtree to look for.
		 */
		sub = find_subtree(it, path, slash - path, 0);
		if (!sub)
			return NULL;
		it = sub->cache_tree;
		if (slash)
			while (*slash && *slash == '/')
				slash++;
		if (!slash || !*slash)
			return it; /* prefix ended with slashes */
		path = slash;
	}
	return it;
}
Commit	Line	Data
74986462 JH	1	#include "cache.h"
	2	#include "tree.h"
	3	#include "cache-tree.h"
	4
	5	#define DEBUG 0
	6
	7	struct cache_tree *cache_tree(void)
	8	{
	9	struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
	10	it->entry_count = -1;
	11	return it;
	12	}
	13
bad68ec9	14	void cache_tree_free(struct cache_tree **it_p)
74986462 JH	15	{
74986462 JH	16	int i;
bad68ec9	17	struct cache_tree it = it_p;
74986462 JH	18
	19	if (!it)
	20	return;
	21	for (i = 0; i < it->subtree_nr; i++)
61fa3097 JH	22	if (it->down[i])
61fa3097 JH	23	cache_tree_free(&it->down[i]->cache_tree);
74986462 JH	24	free(it->down);
74986462 JH	25	free(it);
bad68ec9	26	*it_p = NULL;
74986462 JH	27	}
74986462 JH	28
61fa3097 JH	29	static int subtree_name_cmp(const char *one, int onelen,
	30	const char *two, int twolen)
	31	{
	32	if (onelen < twolen)
	33	return -1;
	34	if (twolen < onelen)
	35	return 1;
	36	return memcmp(one, two, onelen);
	37	}
	38
	39	static int subtree_pos(struct cache_tree it, const char path, int pathlen)
	40	{
	41	struct cache_tree_sub **down = it->down;
	42	int lo, hi;
	43	lo = 0;
	44	hi = it->subtree_nr;
	45	while (lo < hi) {
	46	int mi = (lo + hi) / 2;
	47	struct cache_tree_sub *mdl = down[mi];
	48	int cmp = subtree_name_cmp(path, pathlen,
	49	mdl->name, mdl->namelen);
	50	if (!cmp)
	51	return mi;
	52	if (cmp < 0)
	53	hi = mi;
	54	else
	55	lo = mi + 1;
	56	}
	57	return -lo-1;
	58	}
	59
74986462 JH	60	static struct cache_tree_sub find_subtree(struct cache_tree it,
	61	const char *path,
	62	int pathlen,
	63	int create)
	64	{
74986462	65	struct cache_tree_sub *down;
61fa3097 JH	66	int pos = subtree_pos(it, path, pathlen);
	67	if (0 <= pos)
	68	return it->down[pos];
74986462 JH	69	if (!create)
74986462 JH	70	return NULL;
61fa3097 JH	71
61fa3097 JH	72	pos = -pos-1;
74986462 JH	73	if (it->subtree_alloc <= it->subtree_nr) {
	74	it->subtree_alloc = alloc_nr(it->subtree_alloc);
	75	it->down = xrealloc(it->down, it->subtree_alloc *
	76	sizeof(*it->down));
	77	}
61fa3097 JH	78	it->subtree_nr++;
61fa3097 JH	79
74986462	80	down = xmalloc(sizeof(*down) + pathlen + 1);
61fa3097	81	down->cache_tree = NULL;
74986462 JH	82	down->namelen = pathlen;
74986462 JH	83	memcpy(down->name, path, pathlen);
61fa3097 JH	84	down->name[pathlen] = 0;
	85
	86	if (pos < it->subtree_nr)
	87	memmove(it->down + pos + 1,
	88	it->down + pos,
	89	sizeof(down) * (it->subtree_nr - pos - 1));
	90	it->down[pos] = down;
74986462 JH	91	return down;
	92	}
	93
7927a55d JH	94	struct cache_tree_sub cache_tree_sub(struct cache_tree it, const char *path)
	95	{
	96	int pathlen = strlen(path);
	97	return find_subtree(it, path, pathlen, 1);
	98	}
	99
74986462 JH	100	void cache_tree_invalidate_path(struct cache_tree it, const char path)
	101	{
	102	/* a/b/c
	103	* ==> invalidate self
	104	* ==> find "a", have it invalidate "b/c"
	105	* a
	106	* ==> invalidate self
	107	* ==> if "a" exists as a subtree, remove it.
	108	*/
	109	const char *slash;
	110	int namelen;
	111	struct cache_tree_sub *down;
	112
00703e6d JH	113	#if DEBUG
	114	fprintf(stderr, "cache-tree invalidate <%s>\n", path);
	115	#endif
	116
74986462 JH	117	if (!it)
	118	return;
	119	slash = strchr(path, '/');
	120	it->entry_count = -1;
	121	if (!slash) {
61fa3097	122	int pos;
74986462	123	namelen = strlen(path);
61fa3097 JH	124	pos = subtree_pos(it, path, namelen);
	125	if (0 <= pos) {
	126	cache_tree_free(&it->down[pos]->cache_tree);
	127	free(it->down[pos]);
74986462 JH	128	/* 0 1 2 3 4 5
74986462 JH	129	* ^ ^subtree_nr = 6
61fa3097	130	* pos
74986462	131	* move 4 and 5 up one place (2 entries)
61fa3097	132	* 2 = 6 - 3 - 1 = subtree_nr - pos - 1
74986462	133	*/
61fa3097	134	memmove(it->down+pos, it->down+pos+1,
74986462	135	sizeof(struct cache_tree_sub )
61fa3097	136	(it->subtree_nr - pos - 1));
74986462 JH	137	it->subtree_nr--;
	138	}
	139	return;
	140	}
	141	namelen = slash - path;
	142	down = find_subtree(it, path, namelen, 0);
	143	if (down)
	144	cache_tree_invalidate_path(down->cache_tree, slash + 1);
	145	}
	146
	147	static int verify_cache(struct cache_entry **cache,
	148	int entries)
	149	{
	150	int i, funny;
	151
	152	/* Verify that the tree is merged */
	153	funny = 0;
	154	for (i = 0; i < entries; i++) {
	155	struct cache_entry *ce = cache[i];
	156	if (ce_stage(ce)) {
	157	if (10 < ++funny) {
	158	fprintf(stderr, "...\n");
	159	break;
	160	}
	161	fprintf(stderr, "%s: unmerged (%s)\n",
	162	ce->name, sha1_to_hex(ce->sha1));
	163	}
	164	}
	165	if (funny)
	166	return -1;
	167
	168	/* Also verify that the cache does not have path and path/file
	169	* at the same time. At this point we know the cache has only
	170	* stage 0 entries.
	171	*/
	172	funny = 0;
	173	for (i = 0; i < entries - 1; i++) {
	174	/* path/file always comes after path because of the way
	175	* the cache is sorted. Also path can appear only once,
	176	* which means conflicting one would immediately follow.
	177	*/
	178	const char *this_name = cache[i]->name;
	179	const char *next_name = cache[i+1]->name;
	180	int this_len = strlen(this_name);
	181	if (this_len < strlen(next_name) &&
	182	strncmp(this_name, next_name, this_len) == 0 &&
	183	next_name[this_len] == '/') {
	184	if (10 < ++funny) {
	185	fprintf(stderr, "...\n");
	186	break;
	187	}
	188	fprintf(stderr, "You have both %s and %s\n",
	189	this_name, next_name);
	190	}
	191	}
	192	if (funny)
	193	return -1;
	194	return 0;
	195	}
	196
	197	static void discard_unused_subtrees(struct cache_tree *it)
	198	{
	199	struct cache_tree_sub **down = it->down;
	200	int nr = it->subtree_nr;
201	int dst, src;
202	for (dst = src = 0; src < nr; src++) {
203	struct cache_tree_sub *s = down[src];
204	if (s->used)
205	down[dst++] = s;
206	else {
bad68ec9	207	cache_tree_free(&s->cache_tree);
74986462 JH	208	free(s);
	209	it->subtree_nr--;
	210	}
	211	}
	212	}
	213
bad68ec9 JH	214	int cache_tree_fully_valid(struct cache_tree *it)
	215	{
	216	int i;
	217	if (!it)
	218	return 0;
	219	if (it->entry_count < 0 \|\| !has_sha1_file(it->sha1))
	220	return 0;
	221	for (i = 0; i < it->subtree_nr; i++) {
	222	if (!cache_tree_fully_valid(it->down[i]->cache_tree))
	223	return 0;
	224	}
	225	return 1;
	226	}
	227
74986462 JH	228	static int update_one(struct cache_tree *it,
	229	struct cache_entry **cache,
	230	int entries,
	231	const char *base,
	232	int baselen,
2956dd3b JH	233	int missing_ok,
2956dd3b JH	234	int dryrun)
74986462 JH	235	{
	236	unsigned long size, offset;
	237	char *buffer;
	238	int i;
	239
dd0c34c4	240	if (0 <= it->entry_count && has_sha1_file(it->sha1))
74986462 JH	241	return it->entry_count;
	242
	243	/*
	244	* We first scan for subtrees and update them; we start by
	245	* marking existing subtrees -- the ones that are unmarked
	246	* should not be in the result.
	247	*/
	248	for (i = 0; i < it->subtree_nr; i++)
	249	it->down[i]->used = 0;
	250
	251	/*
	252	* Find the subtrees and update them.
	253	*/
	254	for (i = 0; i < entries; i++) {
	255	struct cache_entry *ce = cache[i];
	256	struct cache_tree_sub *sub;
	257	const char path, slash;
	258	int pathlen, sublen, subcnt;
	259
	260	path = ce->name;
	261	pathlen = ce_namelen(ce);
	262	if (pathlen <= baselen \|\| memcmp(base, path, baselen))
	263	break; /* at the end of this level */
	264
	265	slash = strchr(path + baselen, '/');
	266	if (!slash)
	267	continue;
	268	/*
	269	* a/bbb/c (base = a/, slash = /c)
	270	* ==>
	271	* path+baselen = bbb/c, sublen = 3
	272	*/
	273	sublen = slash - (path + baselen);
	274	sub = find_subtree(it, path + baselen, sublen, 1);
	275	if (!sub->cache_tree)
	276	sub->cache_tree = cache_tree();
	277	subcnt = update_one(sub->cache_tree,
	278	cache + i, entries - i,
	279	path,
	280	baselen + sublen + 1,
2956dd3b JH	281	missing_ok,
2956dd3b JH	282	dryrun);
74986462 JH	283	i += subcnt - 1;
	284	sub->used = 1;
	285	}
	286
	287	discard_unused_subtrees(it);
	288
	289	/*
	290	* Then write out the tree object for this level.
	291	*/
	292	size = 8192;
	293	buffer = xmalloc(size);
	294	offset = 0;
	295
	296	for (i = 0; i < entries; i++) {
	297	struct cache_entry *ce = cache[i];
	298	struct cache_tree_sub *sub;
	299	const char path, slash;
	300	int pathlen, entlen;
	301	const unsigned char *sha1;
	302	unsigned mode;
	303
	304	path = ce->name;
	305	pathlen = ce_namelen(ce);
	306	if (pathlen <= baselen \|\| memcmp(base, path, baselen))
	307	break; /* at the end of this level */
	308
	309	slash = strchr(path + baselen, '/');
	310	if (slash) {
	311	entlen = slash - (path + baselen);
	312	sub = find_subtree(it, path + baselen, entlen, 0);
	313	if (!sub)
	314	die("cache-tree.c: '%.*s' in '%s' not found",
	315	entlen, path + baselen, path);
	316	i += sub->cache_tree->entry_count - 1;
	317	sha1 = sub->cache_tree->sha1;
	318	mode = S_IFDIR;
	319	}
	320	else {
	321	sha1 = ce->sha1;
	322	mode = ntohl(ce->ce_mode);
	323	entlen = pathlen - baselen;
	324	}
	325	if (!missing_ok && !has_sha1_file(sha1))
	326	return error("invalid object %s", sha1_to_hex(sha1));
	327
	328	if (!ce->ce_mode)
	329	continue; /* entry being removed */
	330
	331	if (size < offset + entlen + 100) {
	332	size = alloc_nr(offset + entlen + 100);
	333	buffer = xrealloc(buffer, size);
	334	}
	335	offset += sprintf(buffer + offset,
	336	"%o %.*s", mode, entlen, path + baselen);
	337	buffer[offset++] = 0;
e702496e	338	hashcpy((unsigned char*)buffer + offset, sha1);
74986462 JH	339	offset += 20;
	340
	341	#if DEBUG
00703e6d	342	fprintf(stderr, "cache-tree update-one %o %.*s\n",
74986462 JH	343	mode, entlen, path + baselen);
	344	#endif
	345	}
	346
abdc3fc8 RS	347	if (dryrun)
abdc3fc8 RS	348	hash_sha1_file(buffer, offset, tree_type, it->sha1);
2956dd3b JH	349	else
2956dd3b JH	350	write_sha1_file(buffer, offset, tree_type, it->sha1);
74986462 JH	351	free(buffer);
	352	it->entry_count = i;
	353	#if DEBUG
00703e6d	354	fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
74986462 JH	355	it->entry_count, it->subtree_nr,
	356	sha1_to_hex(it->sha1));
	357	#endif
	358	return i;
	359	}
	360
	361	int cache_tree_update(struct cache_tree *it,
	362	struct cache_entry **cache,
	363	int entries,
2956dd3b JH	364	int missing_ok,
2956dd3b JH	365	int dryrun)
74986462 JH	366	{
	367	int i;
	368	i = verify_cache(cache, entries);
	369	if (i)
	370	return i;
2956dd3b	371	i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
74986462 JH	372	if (i < 0)
	373	return i;
	374	return 0;
	375	}
	376
	377	static void write_one(struct cache_tree it,
	378	char *path,
	379	int pathlen,
	380	char *buffer,
	381	unsigned long *size,
	382	unsigned long *offset)
	383	{
	384	int i;
	385
	386	/* One "cache-tree" entry consists of the following:
	387	* path (NUL terminated)
	388	* entry_count, subtree_nr ("%d %d\n")
	389	* tree-sha1 (missing if invalid)
	390	* subtree_nr "cache-tree" entries for subtrees.
	391	*/
	392	if (size < offset + pathlen + 100) {
	393	size = alloc_nr(offset + pathlen + 100);
	394	buffer = xrealloc(buffer, *size);
	395	}
	396	offset += sprintf(buffer + offset, "%.*s%c%d %d\n",
	397	pathlen, path, 0,
	398	it->entry_count, it->subtree_nr);
	399
	400	#if DEBUG
	401	if (0 <= it->entry_count)
	402	fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
	403	pathlen, path, it->entry_count, it->subtree_nr,
	404	sha1_to_hex(it->sha1));
	405	else
	406	fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
	407	pathlen, path, it->subtree_nr);
	408	#endif
	409
	410	if (0 <= it->entry_count) {
e702496e	411	hashcpy((unsigned char)buffer + offset, it->sha1);
74986462 JH	412	*offset += 20;
	413	}
	414	for (i = 0; i < it->subtree_nr; i++) {
	415	struct cache_tree_sub *down = it->down[i];
61fa3097 JH	416	if (i) {
	417	struct cache_tree_sub *prev = it->down[i-1];
	418	if (subtree_name_cmp(down->name, down->namelen,
	419	prev->name, prev->namelen) <= 0)
	420	die("fatal - unsorted cache subtree");
	421	}
74986462 JH	422	buffer = write_one(down->cache_tree, down->name, down->namelen,
	423	buffer, size, offset);
	424	}
	425	return buffer;
	426	}
	427
bad68ec9	428	void cache_tree_write(struct cache_tree root, unsigned long *size_p)
74986462 JH	429	{
	430	char path[PATH_MAX];
	431	unsigned long size = 8192;
	432	char *buffer = xmalloc(size);
	433
bad68ec9	434	*size_p = 0;
74986462	435	path[0] = 0;
bad68ec9	436	return write_one(root, path, 0, buffer, &size, size_p);
74986462 JH	437	}
	438
	439	static struct cache_tree read_one(const char buffer, unsigned long size_p)
	440	{
	441	const char buf = buffer;
	442	unsigned long size = *size_p;
0111ea38 JS	443	const char *cp;
0111ea38 JS	444	char *ep;
74986462 JH	445	struct cache_tree *it;
	446	int i, subtree_nr;
	447
	448	it = NULL;
	449	/* skip name, but make sure name exists */
	450	while (size && *buf) {
	451	size--;
	452	buf++;
	453	}
	454	if (!size)
	455	goto free_return;
	456	buf++; size--;
	457	it = cache_tree();
0111ea38 JS	458
	459	cp = buf;
	460	it->entry_count = strtol(cp, &ep, 10);
	461	if (cp == ep)
	462	goto free_return;
	463	cp = ep;
	464	subtree_nr = strtol(cp, &ep, 10);
	465	if (cp == ep)
74986462 JH	466	goto free_return;
	467	while (size && buf && buf != '\n') {
	468	size--;
	469	buf++;
	470	}
	471	if (!size)
	472	goto free_return;
	473	buf++; size--;
	474	if (0 <= it->entry_count) {
	475	if (size < 20)
	476	goto free_return;
e702496e	477	hashcpy(it->sha1, (unsigned char*)buf);
74986462 JH	478	buf += 20;
	479	size -= 20;
	480	}
	481
	482	#if DEBUG
	483	if (0 <= it->entry_count)
	484	fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
	485	*buffer, it->entry_count, subtree_nr,
	486	sha1_to_hex(it->sha1));
	487	else
	488	fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
	489	*buffer, subtree_nr);
	490	#endif
	491
	492	/*
	493	* Just a heuristic -- we do not add directories that often but
	494	* we do not want to have to extend it immediately when we do,
	495	* hence +2.
	496	*/
	497	it->subtree_alloc = subtree_nr + 2;
	498	it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
	499	for (i = 0; i < subtree_nr; i++) {
	500	/* read each subtree */
	501	struct cache_tree *sub;
61fa3097	502	struct cache_tree_sub *subtree;
74986462	503	const char *name = buf;
7927a55d	504
74986462 JH	505	sub = read_one(&buf, &size);
	506	if (!sub)
	507	goto free_return;
7927a55d	508	subtree = cache_tree_sub(it, name);
61fa3097	509	subtree->cache_tree = sub;
74986462 JH	510	}
	511	if (subtree_nr != it->subtree_nr)
	512	die("cache-tree: internal error");
	513	*buffer = buf;
	514	*size_p = size;
	515	return it;
	516
	517	free_return:
bad68ec9	518	cache_tree_free(&it);
74986462 JH	519	return NULL;
	520	}
	521
bad68ec9	522	struct cache_tree cache_tree_read(const char buffer, unsigned long size)
74986462	523	{
bad68ec9	524	if (buffer[0])
74986462	525	return NULL; /* not the whole tree */
74986462 JH	526	return read_one(&buffer, &size);
74986462 JH	527	}
6bd20358 JH	528
	529	struct cache_tree cache_tree_find(struct cache_tree it, const char *path)
	530	{
	531	while (*path) {
	532	const char *slash;
	533	struct cache_tree_sub *sub;
	534
	535	slash = strchr(path, '/');
	536	if (!slash)
	537	slash = path + strlen(path);
	538	/* between path and slash is the name of the
	539	* subtree to look for.
	540	*/
	541	sub = find_subtree(it, path, slash - path, 0);
	542	if (!sub)
	543	return NULL;
	544	it = sub->cache_tree;
	545	if (slash)
	546	while (slash && slash == '/')
	547	slash++;
	548	if (!slash \|\| !*slash)
	549	return it; /* prefix ended with slashes */
	550	path = slash;
	551	}
	552	return it;
	553	}