[git/git.git] / read-cache.c

/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"

const char *sha1_file_directory = NULL;
struct cache_entry **active_cache = NULL;
unsigned int active_nr = 0, active_alloc = 0;

void usage(const char *err)
{
	fprintf(stderr, "read-tree: %s\n", err);
	exit(1);
}

static unsigned hexval(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	if (c >= 'A' && c <= 'F')
		return c - 'A' + 10;
	return ~0;
}

int get_sha1_hex(const char *hex, unsigned char *sha1)
{
	int i;
	for (i = 0; i < 20; i++) {
		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
		if (val & ~0xff)
			return -1;
		*sha1++ = val;
		hex += 2;
	}
	return 0;
}

char * sha1_to_hex(const unsigned char *sha1)
{
	static char buffer[50];
	static const char hex[] = "0123456789abcdef";
	char *buf = buffer;
	int i;

	for (i = 0; i < 20; i++) {
		unsigned int val = *sha1++;
		*buf++ = hex[val >> 4];
		*buf++ = hex[val & 0xf];
	}
	return buffer;
}

/*
 * NOTE! This returns a statically allocated buffer, so you have to be
 * careful about using it. Do a "strdup()" if you need to save the
 * filename.
 */
char *sha1_file_name(unsigned char *sha1)
{
	int i;
	static char *name, *base;

	if (!base) {
		char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
		int len = strlen(sha1_file_directory);
		base = malloc(len + 60);
		memcpy(base, sha1_file_directory, len);
		memset(base+len, 0, 60);
		base[len] = '/';
		base[len+3] = '/';
		name = base + len + 1;
	}
	for (i = 0; i < 20; i++) {
		static char hex[] = "0123456789abcdef";
		unsigned int val = sha1[i];
		char *pos = name + i*2 + (i > 0);
		*pos++ = hex[val >> 4];
		*pos = hex[val & 0xf];
	}
	return base;
}

int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
{
	unsigned char real_sha1[20];
	SHA_CTX c;

	SHA1_Init(&c);
	SHA1_Update(&c, map, size);
	SHA1_Final(real_sha1, &c);
	return memcmp(sha1, real_sha1, 20) ? -1 : 0;
}

void *map_sha1_file(unsigned char *sha1, unsigned long *size)
{
	char *filename = sha1_file_name(sha1);
	int fd = open(filename, O_RDONLY);
	struct stat st;
	void *map;

	if (fd < 0) {
		perror(filename);
		return NULL;
	}
	if (fstat(fd, &st) < 0) {
		close(fd);  
		return NULL;
	}
	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	close(fd);
	if (-1 == (int)(long)map)
		return NULL;
	*size = st.st_size;
	return map;
}

void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
{
	int ret, bytes;
	z_stream stream;
	char buffer[8192];
	char *buf;

	/* Get the data stream */
	memset(&stream, 0, sizeof(stream));
	stream.next_in = map;
	stream.avail_in = mapsize;
	stream.next_out = buffer;
	stream.avail_out = sizeof(buffer);

	inflateInit(&stream);
	ret = inflate(&stream, 0);
	if (sscanf(buffer, "%10s %lu", type, size) != 2)
		return NULL;

	bytes = strlen(buffer) + 1;
	buf = malloc(*size);
	if (!buf)
		return NULL;

	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	bytes = stream.total_out - bytes;
	if (bytes < *size && ret == Z_OK) {
		stream.next_out = buf + bytes;
		stream.avail_out = *size - bytes;
		while (inflate(&stream, Z_FINISH) == Z_OK)
			/* nothing */;
	}
	inflateEnd(&stream);
	return buf;
}

void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
{
	unsigned long mapsize;
	void *map, *buf;

	map = map_sha1_file(sha1, &mapsize);
	if (map) {
		buf = unpack_sha1_file(map, mapsize, type, size);
		munmap(map, mapsize);
		return buf;
	}
	return NULL;
}

int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
{
	int size;
	char *compressed;
	z_stream stream;
	unsigned char sha1[20];
	SHA_CTX c;

	/* Set it up */
	memset(&stream, 0, sizeof(stream));
	deflateInit(&stream, Z_BEST_COMPRESSION);
	size = deflateBound(&stream, len);
	compressed = malloc(size);

	/* Compress it */
	stream.next_in = buf;
	stream.avail_in = len;
	stream.next_out = compressed;
	stream.avail_out = size;
	while (deflate(&stream, Z_FINISH) == Z_OK)
		/* nothing */;
	deflateEnd(&stream);
	size = stream.total_out;

	/* Sha1.. */
	SHA1_Init(&c);
	SHA1_Update(&c, compressed, size);
	SHA1_Final(sha1, &c);

	if (write_sha1_buffer(sha1, compressed, size) < 0)
		return -1;
	if (returnsha1)
		memcpy(returnsha1, sha1, 20);
	return 0;
}

int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
{
	char *filename = sha1_file_name(sha1);
	int fd;

	fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
	if (fd < 0)
		return (errno == EEXIST) ? 0 : -1;
	write(fd, buf, size);
	close(fd);
	return 0;
}

static int error(const char * string)
{
	fprintf(stderr, "error: %s\n", string);
	return -1;
}

int cache_match_stat(struct cache_entry *ce, struct stat *st)
{
	unsigned int changed = 0;

	if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec ||
	    ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
		changed |= MTIME_CHANGED;
	if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec ||
	    ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
		changed |= CTIME_CHANGED;
	if (ce->st_uid != (unsigned int)st->st_uid ||
	    ce->st_gid != (unsigned int)st->st_gid)
		changed |= OWNER_CHANGED;
	if (ce->st_mode != (unsigned int)st->st_mode)
		changed |= MODE_CHANGED;
	if (ce->st_dev != (unsigned int)st->st_dev ||
	    ce->st_ino != (unsigned int)st->st_ino)
		changed |= INODE_CHANGED;
	if (ce->st_size != (unsigned int)st->st_size)
		changed |= DATA_CHANGED;
	return changed;
}

int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
{
	int len = len1 < len2 ? len1 : len2;
	int cmp;

	cmp = memcmp(name1, name2, len);
	if (cmp)
		return cmp;
	if (len1 < len2)
		return -1;
	if (len1 > len2)
		return 1;
	return 0;
}

int cache_name_pos(const char *name, int namelen)
{
	int first, last;

	first = 0;
	last = active_nr;
	while (last > first) {
		int next = (last + first) >> 1;
		struct cache_entry *ce = active_cache[next];
		int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
		if (!cmp)
			return -next-1;
		if (cmp < 0) {
			last = next;
			continue;
		}
		first = next+1;
	}
	return first;
}

int remove_file_from_cache(char *path)
{
	int pos = cache_name_pos(path, strlen(path));
	if (pos < 0) {
		pos = -pos-1;
		active_nr--;
		if (pos < active_nr)
			memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
	}
	return 0;
}

int add_cache_entry(struct cache_entry *ce)
{
	int pos;

	pos = cache_name_pos(ce->name, ce->namelen);

	/* existing match? Just replace it */
	if (pos < 0) {
		active_cache[-pos-1] = ce;
		return 0;
	}

	/* Make sure the array is big enough .. */
	if (active_nr == active_alloc) {
		active_alloc = alloc_nr(active_alloc);
		active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
	}

	/* Add it in.. */
	active_nr++;
	if (active_nr > pos)
		memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
	active_cache[pos] = ce;
	return 0;
}

static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
	SHA_CTX c;
	unsigned char sha1[20];

	if (hdr->signature != CACHE_SIGNATURE)
		return error("bad signature");
	if (hdr->version != 1)
		return error("bad version");
	SHA1_Init(&c);
	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	SHA1_Final(sha1, &c);
	if (memcmp(sha1, hdr->sha1, 20))
		return error("bad header sha1");
	return 0;
}

int read_cache(void)
{
	int fd, i;
	struct stat st;
	unsigned long size, offset;
	void *map;
	struct cache_header *hdr;

	errno = EBUSY;
	if (active_cache)
		return error("more than one cachefile");
	errno = ENOENT;
	sha1_file_directory = getenv(DB_ENVIRONMENT);
	if (!sha1_file_directory)
		sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	if (access(sha1_file_directory, X_OK) < 0)
		return error("no access to SHA1 file directory");
	fd = open(".dircache/index", O_RDONLY);
	if (fd < 0)
		return (errno == ENOENT) ? 0 : error("open failed");

	size = 0; // avoid gcc warning
	map = (void *)-1;
	if (!fstat(fd, &st)) {
		size = st.st_size;
		errno = EINVAL;
		if (size >= sizeof(struct cache_header))
			map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	}
	close(fd);
	if (-1 == (int)(long)map)
		return error("mmap failed");

	hdr = map;
	if (verify_hdr(hdr, size) < 0)
		goto unmap;

	active_nr = hdr->entries;
	active_alloc = alloc_nr(active_nr);
	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));

	offset = sizeof(*hdr);
	for (i = 0; i < hdr->entries; i++) {
		struct cache_entry *ce = map + offset;
		offset = offset + ce_size(ce);
		active_cache[i] = ce;
	}
	return active_nr;

unmap:
	munmap(map, size);
	errno = EINVAL;
	return error("verify header failed");
}

int write_cache(int newfd, struct cache_entry **cache, int entries)
{
	SHA_CTX c;
	struct cache_header hdr;
	int i;

	hdr.signature = CACHE_SIGNATURE;
	hdr.version = 1;
	hdr.entries = entries;

	SHA1_Init(&c);
	SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
	for (i = 0; i < entries; i++) {
		struct cache_entry *ce = cache[i];
		int size = ce_size(ce);
		SHA1_Update(&c, ce, size);
	}
	SHA1_Final(hdr.sha1, &c);

	if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;

	for (i = 0; i < entries; i++) {
		struct cache_entry *ce = cache[i];
		int size = ce_size(ce);
		if (write(newfd, ce, size) != size)
			return -1;
	}
	return 0;
}
Commit	Line	Data
8bc9a0c7 LT	1	/*
	2	* GIT - The information manager from hell
	3	*
	4	* Copyright (C) Linus Torvalds, 2005
	5	*/
e83c5163 LT	6	#include "cache.h"
	7
	8	const char *sha1_file_directory = NULL;
	9	struct cache_entry **active_cache = NULL;
	10	unsigned int active_nr = 0, active_alloc = 0;
	11
	12	void usage(const char *err)
	13	{
	14	fprintf(stderr, "read-tree: %s\n", err);
	15	exit(1);
	16	}
	17
	18	static unsigned hexval(char c)
	19	{
	20	if (c >= '0' && c <= '9')
	21	return c - '0';
	22	if (c >= 'a' && c <= 'f')
	23	return c - 'a' + 10;
	24	if (c >= 'A' && c <= 'F')
	25	return c - 'A' + 10;
	26	return ~0;
	27	}
	28
197ee8c9	29	int get_sha1_hex(const char hex, unsigned char sha1)
e83c5163 LT	30	{
	31	int i;
	32	for (i = 0; i < 20; i++) {
	33	unsigned int val = (hexval(hex[0]) << 4) \| hexval(hex[1]);
	34	if (val & ~0xff)
	35	return -1;
	36	*sha1++ = val;
	37	hex += 2;
	38	}
	39	return 0;
	40	}
	41
197ee8c9	42	char * sha1_to_hex(const unsigned char *sha1)
e83c5163 LT	43	{
	44	static char buffer[50];
	45	static const char hex[] = "0123456789abcdef";
	46	char *buf = buffer;
	47	int i;
	48
	49	for (i = 0; i < 20; i++) {
	50	unsigned int val = *sha1++;
	51	*buf++ = hex[val >> 4];
	52	*buf++ = hex[val & 0xf];
	53	}
	54	return buffer;
	55	}
	56
	57	/*
	58	* NOTE! This returns a statically allocated buffer, so you have to be
	59	* careful about using it. Do a "strdup()" if you need to save the
	60	* filename.
	61	*/
	62	char sha1_file_name(unsigned char sha1)
	63	{
	64	int i;
	65	static char name, base;
	66
	67	if (!base) {
	68	char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
	69	int len = strlen(sha1_file_directory);
	70	base = malloc(len + 60);
	71	memcpy(base, sha1_file_directory, len);
	72	memset(base+len, 0, 60);
	73	base[len] = '/';
	74	base[len+3] = '/';
	75	name = base + len + 1;
	76	}
	77	for (i = 0; i < 20; i++) {
	78	static char hex[] = "0123456789abcdef";
	79	unsigned int val = sha1[i];
	80	char pos = name + i2 + (i > 0);
	81	*pos++ = hex[val >> 4];
	82	*pos = hex[val & 0xf];
	83	}
	84	return base;
	85	}
	86
2ade9340 LT	87	int check_sha1_signature(unsigned char sha1, void map, unsigned long size)
	88	{
	89	unsigned char real_sha1[20];
	90	SHA_CTX c;
	91
	92	SHA1_Init(&c);
	93	SHA1_Update(&c, map, size);
	94	SHA1_Final(real_sha1, &c);
	95	return memcmp(sha1, real_sha1, 20) ? -1 : 0;
	96	}
	97
24778e33	98	void map_sha1_file(unsigned char sha1, unsigned long *size)
e83c5163	99	{
e83c5163	100	char *filename = sha1_file_name(sha1);
24778e33 LT	101	int fd = open(filename, O_RDONLY);
	102	struct stat st;
	103	void *map;
e83c5163	104
e83c5163 LT	105	if (fd < 0) {
	106	perror(filename);
	107	return NULL;
	108	}
	109	if (fstat(fd, &st) < 0) {
24778e33	110	close(fd);
e83c5163 LT	111	return NULL;
	112	}
	113	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	114	close(fd);
	115	if (-1 == (int)(long)map)
	116	return NULL;
24778e33 LT	117	*size = st.st_size;
	118	return map;
	119	}
	120
	121	void * unpack_sha1_file(void map, unsigned long mapsize, char type, unsigned long *size)
	122	{
	123	int ret, bytes;
	124	z_stream stream;
	125	char buffer[8192];
	126	char *buf;
e83c5163 LT	127
	128	/* Get the data stream */
	129	memset(&stream, 0, sizeof(stream));
	130	stream.next_in = map;
24778e33	131	stream.avail_in = mapsize;
e83c5163 LT	132	stream.next_out = buffer;
	133	stream.avail_out = sizeof(buffer);
	134
	135	inflateInit(&stream);
	136	ret = inflate(&stream, 0);
	137	if (sscanf(buffer, "%10s %lu", type, size) != 2)
	138	return NULL;
24778e33	139
e83c5163 LT	140	bytes = strlen(buffer) + 1;
	141	buf = malloc(*size);
	142	if (!buf)
	143	return NULL;
	144
	145	memcpy(buf, buffer + bytes, stream.total_out - bytes);
	146	bytes = stream.total_out - bytes;
	147	if (bytes < *size && ret == Z_OK) {
	148	stream.next_out = buf + bytes;
	149	stream.avail_out = *size - bytes;
	150	while (inflate(&stream, Z_FINISH) == Z_OK)
	151	/* nothing */;
	152	}
	153	inflateEnd(&stream);
	154	return buf;
	155	}
	156
24778e33 LT	157	void * read_sha1_file(unsigned char sha1, char type, unsigned long *size)
	158	{
	159	unsigned long mapsize;
	160	void map, buf;
	161
	162	map = map_sha1_file(sha1, &mapsize);
	163	if (map) {
	164	buf = unpack_sha1_file(map, mapsize, type, size);
	165	munmap(map, mapsize);
	166	return buf;
	167	}
	168	return NULL;
	169	}
	170
d6d3f9d0	171	int write_sha1_file(char buf, unsigned len, unsigned char returnsha1)
e83c5163 LT	172	{
	173	int size;
	174	char *compressed;
	175	z_stream stream;
	176	unsigned char sha1[20];
	177	SHA_CTX c;
	178
	179	/* Set it up */
	180	memset(&stream, 0, sizeof(stream));
	181	deflateInit(&stream, Z_BEST_COMPRESSION);
	182	size = deflateBound(&stream, len);
	183	compressed = malloc(size);
	184
	185	/* Compress it */
	186	stream.next_in = buf;
	187	stream.avail_in = len;
	188	stream.next_out = compressed;
	189	stream.avail_out = size;
	190	while (deflate(&stream, Z_FINISH) == Z_OK)
	191	/* nothing */;
	192	deflateEnd(&stream);
	193	size = stream.total_out;
	194
	195	/* Sha1.. */
	196	SHA1_Init(&c);
	197	SHA1_Update(&c, compressed, size);
	198	SHA1_Final(sha1, &c);
	199
	200	if (write_sha1_buffer(sha1, compressed, size) < 0)
	201	return -1;
d6d3f9d0 LT	202	if (returnsha1)
d6d3f9d0 LT	203	memcpy(returnsha1, sha1, 20);
e83c5163 LT	204	return 0;
	205	}
	206
	207	int write_sha1_buffer(unsigned char sha1, void buf, unsigned int size)
	208	{
	209	char *filename = sha1_file_name(sha1);
19b2860c	210	int fd;
e83c5163 LT	211
	212	fd = open(filename, O_WRONLY \| O_CREAT \| O_EXCL, 0666);
	213	if (fd < 0)
	214	return (errno == EEXIST) ? 0 : -1;
	215	write(fd, buf, size);
	216	close(fd);
	217	return 0;
	218	}
	219
	220	static int error(const char * string)
	221	{
	222	fprintf(stderr, "error: %s\n", string);
	223	return -1;
	224	}
	225
734aab75 LT	226	int cache_match_stat(struct cache_entry ce, struct stat st)
	227	{
	228	unsigned int changed = 0;
	229
	230	if (ce->mtime.sec != (unsigned int)st->st_mtim.tv_sec \|\|
	231	ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
	232	changed \|= MTIME_CHANGED;
	233	if (ce->ctime.sec != (unsigned int)st->st_ctim.tv_sec \|\|
	234	ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
	235	changed \|= CTIME_CHANGED;
	236	if (ce->st_uid != (unsigned int)st->st_uid \|\|
	237	ce->st_gid != (unsigned int)st->st_gid)
	238	changed \|= OWNER_CHANGED;
	239	if (ce->st_mode != (unsigned int)st->st_mode)
	240	changed \|= MODE_CHANGED;
	241	if (ce->st_dev != (unsigned int)st->st_dev \|\|
	242	ce->st_ino != (unsigned int)st->st_ino)
	243	changed \|= INODE_CHANGED;
	244	if (ce->st_size != (unsigned int)st->st_size)
	245	changed \|= DATA_CHANGED;
	246	return changed;
	247	}
	248
79517a06	249	int cache_name_compare(const char name1, int len1, const char name2, int len2)
eb38c22f LT	250	{
	251	int len = len1 < len2 ? len1 : len2;
	252	int cmp;
	253
	254	cmp = memcmp(name1, name2, len);
	255	if (cmp)
	256	return cmp;
	257	if (len1 < len2)
	258	return -1;
	259	if (len1 > len2)
	260	return 1;
	261	return 0;
	262	}
	263
	264	int cache_name_pos(const char *name, int namelen)
	265	{
	266	int first, last;
	267
	268	first = 0;
	269	last = active_nr;
	270	while (last > first) {
	271	int next = (last + first) >> 1;
	272	struct cache_entry *ce = active_cache[next];
	273	int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
	274	if (!cmp)
	275	return -next-1;
	276	if (cmp < 0) {
	277	last = next;
	278	continue;
	279	}
	280	first = next+1;
	281	}
	282	return first;
	283	}
	284
197ee8c9 LT	285	int remove_file_from_cache(char *path)
	286	{
	287	int pos = cache_name_pos(path, strlen(path));
	288	if (pos < 0) {
	289	pos = -pos-1;
	290	active_nr--;
	291	if (pos < active_nr)
	292	memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
	293	}
	294	return 0;
	295	}
	296
	297	int add_cache_entry(struct cache_entry *ce)
	298	{
	299	int pos;
	300
	301	pos = cache_name_pos(ce->name, ce->namelen);
	302
	303	/* existing match? Just replace it */
	304	if (pos < 0) {
	305	active_cache[-pos-1] = ce;
	306	return 0;
	307	}
	308
	309	/* Make sure the array is big enough .. */
	310	if (active_nr == active_alloc) {
	311	active_alloc = alloc_nr(active_alloc);
	312	active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
	313	}
	314
	315	/* Add it in.. */
	316	active_nr++;
	317	if (active_nr > pos)
	318	memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
	319	active_cache[pos] = ce;
	320	return 0;
	321	}
	322
e83c5163 LT	323	static int verify_hdr(struct cache_header *hdr, unsigned long size)
	324	{
	325	SHA_CTX c;
	326	unsigned char sha1[20];
	327
	328	if (hdr->signature != CACHE_SIGNATURE)
	329	return error("bad signature");
	330	if (hdr->version != 1)
	331	return error("bad version");
	332	SHA1_Init(&c);
	333	SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
	334	SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
	335	SHA1_Final(sha1, &c);
	336	if (memcmp(sha1, hdr->sha1, 20))
	337	return error("bad header sha1");
	338	return 0;
	339	}
	340
	341	int read_cache(void)
	342	{
	343	int fd, i;
	344	struct stat st;
	345	unsigned long size, offset;
	346	void *map;
	347	struct cache_header *hdr;
	348
	349	errno = EBUSY;
	350	if (active_cache)
	351	return error("more than one cachefile");
	352	errno = ENOENT;
	353	sha1_file_directory = getenv(DB_ENVIRONMENT);
	354	if (!sha1_file_directory)
	355	sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
	356	if (access(sha1_file_directory, X_OK) < 0)
	357	return error("no access to SHA1 file directory");
	358	fd = open(".dircache/index", O_RDONLY);
	359	if (fd < 0)
	360	return (errno == ENOENT) ? 0 : error("open failed");
	361
19b2860c	362	size = 0; // avoid gcc warning
e83c5163 LT	363	map = (void *)-1;
e83c5163 LT	364	if (!fstat(fd, &st)) {
e83c5163 LT	365	size = st.st_size;
e83c5163 LT	366	errno = EINVAL;
59c1e249	367	if (size >= sizeof(struct cache_header))
e83c5163 LT	368	map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
	369	}
	370	close(fd);
	371	if (-1 == (int)(long)map)
	372	return error("mmap failed");
	373
	374	hdr = map;
	375	if (verify_hdr(hdr, size) < 0)
	376	goto unmap;
	377
	378	active_nr = hdr->entries;
	379	active_alloc = alloc_nr(active_nr);
	380	active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
	381
	382	offset = sizeof(*hdr);
	383	for (i = 0; i < hdr->entries; i++) {
	384	struct cache_entry *ce = map + offset;
	385	offset = offset + ce_size(ce);
	386	active_cache[i] = ce;
	387	}
	388	return active_nr;
	389
	390	unmap:
	391	munmap(map, size);
	392	errno = EINVAL;
	393	return error("verify header failed");
	394	}
	395
197ee8c9 LT	396	int write_cache(int newfd, struct cache_entry **cache, int entries)
	397	{
	398	SHA_CTX c;
	399	struct cache_header hdr;
	400	int i;
	401
	402	hdr.signature = CACHE_SIGNATURE;
	403	hdr.version = 1;
	404	hdr.entries = entries;
	405
	406	SHA1_Init(&c);
	407	SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
	408	for (i = 0; i < entries; i++) {
	409	struct cache_entry *ce = cache[i];
	410	int size = ce_size(ce);
	411	SHA1_Update(&c, ce, size);
	412	}
	413	SHA1_Final(hdr.sha1, &c);
	414
	415	if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
	416	return -1;
	417
	418	for (i = 0; i < entries; i++) {
	419	struct cache_entry *ce = cache[i];
	420	int size = ce_size(ce);
	421	if (write(newfd, ce, size) != size)
	422	return -1;
	423	}
	424	return 0;
	425	}