update-cache.c - jrn/git - Git at Google

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

 /*
  * Default to not allowing changes to the list of files. The
  * tool doesn't actually care, but this makes it harder to add
  * files to the revision control by mistake by doing something
  * like "update-cache *" and suddenly having all the object
  * files be revision controlled.
  */
 static int allow_add = 0, allow_remove = 0;

 static int index_fd(const char *path, int namelen, struct cache_entry *ce, int fd, struct stat *st)
 {
 	z_stream stream;
 	int max_out_bytes = namelen + st->st_size + 200;
 	void *out = malloc(max_out_bytes);
 	void *metadata = malloc(namelen + 200);
 	void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	SHA_CTX c;

 	close(fd);
 	if (!out || (int)(long)in == -1)
 		return -1;

 	memset(&stream, 0, sizeof(stream));
 	deflateInit(&stream, Z_BEST_COMPRESSION);

 	/*
 	 * ASCII size + nul byte
 	 */
 	stream.next_in = metadata;
 	stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
 	stream.next_out = out;
 	stream.avail_out = max_out_bytes;
 	while (deflate(&stream, 0) == Z_OK)
 		/* nothing */;

 	/*
 	 * File content
 	 */
 	stream.next_in = in;
 	stream.avail_in = st->st_size;
 	while (deflate(&stream, Z_FINISH) == Z_OK)
 		/*nothing */;

 	deflateEnd(&stream);

 	SHA1_Init(&c);
 	SHA1_Update(&c, out, stream.total_out);
 	SHA1_Final(ce->sha1, &c);

 	return write_sha1_buffer(ce->sha1, out, stream.total_out);
 }

 /*
  * This only updates the "non-critical" parts of the directory
  * cache, ie the parts that aren't tracked by GIT, and only used
  * to validate the cache.
  */
 static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 {
 	ce->ctime.sec = st->st_ctime;
 	ce->ctime.nsec = st->st_ctim.tv_nsec;
 	ce->mtime.sec = st->st_mtime;
 	ce->mtime.nsec = st->st_mtim.tv_nsec;
 	ce->st_dev = st->st_dev;
 	ce->st_ino = st->st_ino;
 	ce->st_uid = st->st_uid;
 	ce->st_gid = st->st_gid;
 }

 static int add_file_to_cache(char *path)
 {
 	int size, namelen;
 	struct cache_entry *ce;
 	struct stat st;
 	int fd;

 	fd = open(path, O_RDONLY);
 	if (fd < 0) {
 		if (errno == ENOENT) {
 			if (allow_remove)
 				return remove_file_from_cache(path);
 		}
 		return -1;
 	}
 	if (fstat(fd, &st) < 0) {
 		close(fd);
 		return -1;
 	}
 	namelen = strlen(path);
 	size = cache_entry_size(namelen);
 	ce = malloc(size);
 	memset(ce, 0, size);
 	memcpy(ce->name, path, namelen);
 	fill_stat_cache_info(ce, &st);
 	ce->st_mode = st.st_mode;
 	ce->st_size = st.st_size;
 	ce->namelen = namelen;

 	if (index_fd(path, namelen, ce, fd, &st) < 0)
 		return -1;

 	return add_cache_entry(ce, allow_add);
 }

 static int match_data(int fd, void *buffer, unsigned long size)
 {
 	while (size) {
 		char compare[1024];
 		int ret = read(fd, compare, sizeof(compare));

 		if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
 			return -1;
 		size -= ret;
 		buffer += ret;
 	}
 	return 0;
 }

 static int compare_data(struct cache_entry *ce)
 {
 	int match = -1;
 	int fd = open(ce->name, O_RDONLY);

 	if (fd >= 0) {
 		void *buffer;
 		unsigned long size;
 		char type[10];

 		buffer = read_sha1_file(ce->sha1, type, &size);
 		if (buffer) {
 			if (size == ce->st_size && !strcmp(type, "blob"))
 				match = match_data(fd, buffer, size);
 			free(buffer);
 		}
 		close(fd);
 	}
 	return match;
 }

 /*
  * "refresh" does not calculate a new sha1 file or bring the
  * cache up-to-date for mode/content changes. But what it
  * _does_ do is to "re-match" the stat information of a file
  * with the cache, so that you can refresh the cache for a
  * file that hasn't been changed but where the stat entry is
  * out of date.
  *
  * For example, you'd want to do this after doing a "read-tree",
  * to link up the stat cache details with the proper files.
  */
 static struct cache_entry *refresh_entry(struct cache_entry *ce)
 {
 	struct stat st;
 	struct cache_entry *updated;
 	int changed, size;

 	if (stat(ce->name, &st) < 0)
 		return NULL;

 	changed = cache_match_stat(ce, &st);
 	if (!changed)
 		return ce;

 	/*
 	 * If the length has changed, there's no point in trying
 	 * to refresh the entry - it's not going to match
 	 */
 	if (changed & (DATA_CHANGED | MODE_CHANGED))
 		return NULL;

 	if (compare_data(ce))
 		return NULL;

 	size = ce_size(ce);
 	updated = malloc(size);
 	memcpy(updated, ce, size);
 	fill_stat_cache_info(updated, &st);
 	return updated;
 }

 static void refresh_cache(void)
 {
 	int i;

 	for (i = 0; i < active_nr; i++) {
 		struct cache_entry *ce = active_cache[i];
 		struct cache_entry *new = refresh_entry(ce);

 		if (!new) {
 			printf("%s: needs update\n", ce->name);
 			continue;
 		}
 		active_cache[i] = new;
 	}
 }

 /*
  * We fundamentally don't like some paths: we don't want
  * dot or dot-dot anywhere, and in fact, we don't even want
  * any other dot-files (.dircache or anything else). They
  * are hidden, for chist sake.
  *
  * Also, we don't want double slashes or slashes at the
  * end that can make pathnames ambiguous.
  */
 static int verify_path(char *path)
 {
 	char c;

 	goto inside;
 	for (;;) {
 		if (!c)
 			return 1;
 		if (c == '/') {
 inside:
 			c = *path++;
 			if (c != '/' && c != '.' && c != '\0')
 				continue;
 			return 0;
 		}
 		c = *path++;
 	}
 }

 int main(int argc, char **argv)
 {
 	int i, newfd, entries;
 	int allow_options = 1;

 	entries = read_cache();
 	if (entries < 0) {
 		perror("cache corrupted");
 		return -1;
 	}

 	newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
 	if (newfd < 0) {
 		perror("unable to create new cachefile");
 		return -1;
 	}
 	for (i = 1 ; i < argc; i++) {
 		char *path = argv[i];

 		if (allow_options && *path == '-') {
 			if (!strcmp(path, "--")) {
 				allow_options = 0;
 				continue;
 			}
 			if (!strcmp(path, "--add")) {
 				allow_add = 1;
 				continue;
 			}
 			if (!strcmp(path, "--remove")) {
 				allow_remove = 1;
 				continue;
 			}
 			if (!strcmp(path, "--refresh")) {
 				refresh_cache();
 				continue;
 			}
 			usage("unknown option %s", path);
 		}
 		if (!verify_path(path)) {
 			fprintf(stderr, "Ignoring path %s\n", argv[i]);
 			continue;
 		}
 		if (add_file_to_cache(path)) {
 			fprintf(stderr, "Unable to add %s to database\n", path);
 			goto out;
 		}
 	}
 	if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
 		return 0;
 out:
 	unlink(".dircache/index.lock");
 	return 0;
 }
	/*
	* GIT - The information manager from hell
	*
	* Copyright (C) Linus Torvalds, 2005
	*/
	#include "cache.h"

	/*
	* Default to not allowing changes to the list of files. The
	* tool doesn't actually care, but this makes it harder to add
	* files to the revision control by mistake by doing something
	* like "update-cache *" and suddenly having all the object
	* files be revision controlled.
	*/
	static int allow_add = 0, allow_remove = 0;

	static int index_fd(const char path, int namelen, struct cache_entry ce, int fd, struct stat *st)
	{
	z_stream stream;
	int max_out_bytes = namelen + st->st_size + 200;
	void *out = malloc(max_out_bytes);
	void *metadata = malloc(namelen + 200);
	void *in = mmap(NULL, st->st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	SHA_CTX c;

	close(fd);
	if (!out \|\| (int)(long)in == -1)
	return -1;

	memset(&stream, 0, sizeof(stream));
	deflateInit(&stream, Z_BEST_COMPRESSION);

	/*
	* ASCII size + nul byte
	*/
	stream.next_in = metadata;
	stream.avail_in = 1+sprintf(metadata, "blob %lu", (unsigned long) st->st_size);
	stream.next_out = out;
	stream.avail_out = max_out_bytes;
	while (deflate(&stream, 0) == Z_OK)
	/* nothing */;

	/*
	* File content
	*/
	stream.next_in = in;
	stream.avail_in = st->st_size;
	while (deflate(&stream, Z_FINISH) == Z_OK)
	/nothing /;

	deflateEnd(&stream);

	SHA1_Init(&c);
	SHA1_Update(&c, out, stream.total_out);
	SHA1_Final(ce->sha1, &c);

	return write_sha1_buffer(ce->sha1, out, stream.total_out);
	}

	/*
	* This only updates the "non-critical" parts of the directory
	* cache, ie the parts that aren't tracked by GIT, and only used
	* to validate the cache.
	*/
	static void fill_stat_cache_info(struct cache_entry ce, struct stat st)
	{
	ce->ctime.sec = st->st_ctime;
	ce->ctime.nsec = st->st_ctim.tv_nsec;
	ce->mtime.sec = st->st_mtime;
	ce->mtime.nsec = st->st_mtim.tv_nsec;
	ce->st_dev = st->st_dev;
	ce->st_ino = st->st_ino;
	ce->st_uid = st->st_uid;
	ce->st_gid = st->st_gid;
	}

	static int add_file_to_cache(char *path)
	{
	int size, namelen;
	struct cache_entry *ce;
	struct stat st;
	int fd;

	fd = open(path, O_RDONLY);
	if (fd < 0) {
	if (errno == ENOENT) {
	if (allow_remove)
	return remove_file_from_cache(path);
	}
	return -1;
	}
	if (fstat(fd, &st) < 0) {
	close(fd);
	return -1;
	}
	namelen = strlen(path);
	size = cache_entry_size(namelen);
	ce = malloc(size);
	memset(ce, 0, size);
	memcpy(ce->name, path, namelen);
	fill_stat_cache_info(ce, &st);
	ce->st_mode = st.st_mode;
	ce->st_size = st.st_size;
	ce->namelen = namelen;

	if (index_fd(path, namelen, ce, fd, &st) < 0)
	return -1;

	return add_cache_entry(ce, allow_add);
	}

	static int match_data(int fd, void *buffer, unsigned long size)
	{
	while (size) {
	char compare[1024];
	int ret = read(fd, compare, sizeof(compare));

	if (ret <= 0 \|\| ret > size \|\| memcmp(buffer, compare, ret))
	return -1;
	size -= ret;
	buffer += ret;
	}
	return 0;
	}

	static int compare_data(struct cache_entry *ce)
	{
	int match = -1;
	int fd = open(ce->name, O_RDONLY);

	if (fd >= 0) {
	void *buffer;
	unsigned long size;
	char type[10];

	buffer = read_sha1_file(ce->sha1, type, &size);
	if (buffer) {
	if (size == ce->st_size && !strcmp(type, "blob"))
	match = match_data(fd, buffer, size);
	free(buffer);
	}
	close(fd);
	}
	return match;
	}

	/*
	* "refresh" does not calculate a new sha1 file or bring the
	* cache up-to-date for mode/content changes. But what it
	* _does_ do is to "re-match" the stat information of a file
	* with the cache, so that you can refresh the cache for a
	* file that hasn't been changed but where the stat entry is
	* out of date.
	*
	* For example, you'd want to do this after doing a "read-tree",
	* to link up the stat cache details with the proper files.
	*/
	static struct cache_entry refresh_entry(struct cache_entry ce)
	{
	struct stat st;
	struct cache_entry *updated;
	int changed, size;

	if (stat(ce->name, &st) < 0)
	return NULL;

	changed = cache_match_stat(ce, &st);
	if (!changed)
	return ce;

	/*
	* If the length has changed, there's no point in trying
	* to refresh the entry - it's not going to match
	*/
	if (changed & (DATA_CHANGED \| MODE_CHANGED))
	return NULL;

	if (compare_data(ce))
	return NULL;

	size = ce_size(ce);
	updated = malloc(size);
	memcpy(updated, ce, size);
	fill_stat_cache_info(updated, &st);
	return updated;
	}

	static void refresh_cache(void)
	{
	int i;

	for (i = 0; i < active_nr; i++) {
	struct cache_entry *ce = active_cache[i];
	struct cache_entry *new = refresh_entry(ce);

	if (!new) {
	printf("%s: needs update\n", ce->name);
	continue;
	}
	active_cache[i] = new;
	}
	}

	/*
	* We fundamentally don't like some paths: we don't want
	* dot or dot-dot anywhere, and in fact, we don't even want
	* any other dot-files (.dircache or anything else). They
	* are hidden, for chist sake.
	*
	* Also, we don't want double slashes or slashes at the
	* end that can make pathnames ambiguous.
	*/
	static int verify_path(char *path)
	{
	char c;

	goto inside;
	for (;;) {
	if (!c)
	return 1;
	if (c == '/') {
	inside:
	c = *path++;
	if (c != '/' && c != '.' && c != '\0')
	continue;
	return 0;
	}
	c = *path++;
	}
	}

	int main(int argc, char **argv)
	{
	int i, newfd, entries;
	int allow_options = 1;

	entries = read_cache();
	if (entries < 0) {
	perror("cache corrupted");
	return -1;
	}

	newfd = open(".dircache/index.lock", O_RDWR \| O_CREAT \| O_EXCL, 0600);
	if (newfd < 0) {
	perror("unable to create new cachefile");
	return -1;
	}
	for (i = 1 ; i < argc; i++) {
	char *path = argv[i];

	if (allow_options && *path == '-') {
	if (!strcmp(path, "--")) {
	allow_options = 0;
	continue;
	}
	if (!strcmp(path, "--add")) {
	allow_add = 1;
	continue;
	}
	if (!strcmp(path, "--remove")) {
	allow_remove = 1;
	continue;
	}
	if (!strcmp(path, "--refresh")) {
	refresh_cache();
	continue;
	}
	usage("unknown option %s", path);
	}
	if (!verify_path(path)) {
	fprintf(stderr, "Ignoring path %s\n", argv[i]);
	continue;
	}
	if (add_file_to_cache(path)) {
	fprintf(stderr, "Unable to add %s to database\n", path);
	goto out;
	}
	}
	if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
	return 0;
	out:
	unlink(".dircache/index.lock");
	return 0;
	}