builtin-unpack-objects.c - jrn/git - Git at Google

 #include "builtin.h"
 #include "cache.h"
 #include "object.h"
 #include "delta.h"
 #include "pack.h"
 #include "blob.h"
 #include "commit.h"
 #include "tag.h"
 #include "tree.h"

 static int dry_run, quiet, recover, has_errors;
 static const char unpack_usage[] = "git-unpack-objects [-n] [-q] [-r] < pack-file";

 /* We always read in 4kB chunks. */
 static unsigned char buffer[4096];
 static unsigned long offset, len, consumed_bytes;
 static SHA_CTX ctx;

 /*
  * Make sure at least "min" bytes are available in the buffer, and
  * return the pointer to the buffer.
  */
 static void *fill(int min)
 {
 	if (min <= len)
 		return buffer + offset;
 	if (min > sizeof(buffer))
 		die("cannot fill %d bytes", min);
 	if (offset) {
 		SHA1_Update(&ctx, buffer, offset);
 		memmove(buffer, buffer + offset, len);
 		offset = 0;
 	}
 	do {
 		int ret = xread(0, buffer + len, sizeof(buffer) - len);
 		if (ret <= 0) {
 			if (!ret)
 				die("early EOF");
 			die("read error on input: %s", strerror(errno));
 		}
 		len += ret;
 	} while (len < min);
 	return buffer;
 }

 static void use(int bytes)
 {
 	if (bytes > len)
 		die("used more bytes than were available");
 	len -= bytes;
 	offset += bytes;
 	consumed_bytes += bytes;
 }

 static void *get_data(unsigned long size)
 {
 	z_stream stream;
 	void *buf = xmalloc(size);

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

 	stream.next_out = buf;
 	stream.avail_out = size;
 	stream.next_in = fill(1);
 	stream.avail_in = len;
 	inflateInit(&stream);

 	for (;;) {
 		int ret = inflate(&stream, 0);
 		use(len - stream.avail_in);
 		if (stream.total_out == size && ret == Z_STREAM_END)
 			break;
 		if (ret != Z_OK) {
 			error("inflate returned %d\n", ret);
 			free(buf);
 			buf = NULL;
 			if (!recover)
 				exit(1);
 			has_errors = 1;
 			break;
 		}
 		stream.next_in = fill(1);
 		stream.avail_in = len;
 	}
 	inflateEnd(&stream);
 	return buf;
 }

 struct delta_info {
 	unsigned char base_sha1[20];
 	unsigned long base_offset;
 	unsigned long size;
 	void *delta;
 	unsigned nr;
 	struct delta_info *next;
 };

 static struct delta_info *delta_list;

 static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
 			      unsigned long base_offset,
 			      void *delta, unsigned long size)
 {
 	struct delta_info *info = xmalloc(sizeof(*info));

 	hashcpy(info->base_sha1, base_sha1);
 	info->base_offset = base_offset;
 	info->size = size;
 	info->delta = delta;
 	info->nr = nr;
 	info->next = delta_list;
 	delta_list = info;
 }

 struct obj_info {
 	unsigned long offset;
 	unsigned char sha1[20];
 };

 static struct obj_info *obj_list;

 static void added_object(unsigned nr, const char *type, void *data,
 			 unsigned long size);

 static void write_object(unsigned nr, void *buf, unsigned long size,
 			 const char *type)
 {
 	if (write_sha1_file(buf, size, type, obj_list[nr].sha1) < 0)
 		die("failed to write object");
 	added_object(nr, type, buf, size);
 }

 static void resolve_delta(unsigned nr, const char *type,
 			  void *base, unsigned long base_size,
 			  void *delta, unsigned long delta_size)
 {
 	void *result;
 	unsigned long result_size;

 	result = patch_delta(base, base_size,
 			     delta, delta_size,
 			     &result_size);
 	if (!result)
 		die("failed to apply delta");
 	free(delta);
 	write_object(nr, result, result_size, type);
 	free(result);
 }

 static void added_object(unsigned nr, const char *type, void *data,
 			 unsigned long size)
 {
 	struct delta_info **p = &delta_list;
 	struct delta_info *info;

 	while ((info = *p) != NULL) {
 		if (!hashcmp(info->base_sha1, obj_list[nr].sha1) ||
 		    info->base_offset == obj_list[nr].offset) {
 			*p = info->next;
 			p = &delta_list;
 			resolve_delta(info->nr, type, data, size,
 				      info->delta, info->size);
 			free(info);
 			continue;
 		}
 		p = &info->next;
 	}
 }

 static void unpack_non_delta_entry(enum object_type kind, unsigned long size,
 				   unsigned nr)
 {
 	void *buf = get_data(size);
 	const char *type;

 	switch (kind) {
 	case OBJ_COMMIT: type = commit_type; break;
 	case OBJ_TREE:   type = tree_type; break;
 	case OBJ_BLOB:   type = blob_type; break;
 	case OBJ_TAG:    type = tag_type; break;
 	default: die("bad type %d", kind);
 	}
 	if (!dry_run && buf)
 		write_object(nr, buf, size, type);
 	free(buf);
 }

 static void unpack_delta_entry(enum object_type kind, unsigned long delta_size,
 			       unsigned nr)
 {
 	void *delta_data, *base;
 	unsigned long base_size;
 	char type[20];
 	unsigned char base_sha1[20];

 	if (kind == OBJ_REF_DELTA) {
 		hashcpy(base_sha1, fill(20));
 		use(20);
 		delta_data = get_data(delta_size);
 		if (dry_run || !delta_data) {
 			free(delta_data);
 			return;
 		}
 		if (!has_sha1_file(base_sha1)) {
 			hashcpy(obj_list[nr].sha1, null_sha1);
 			add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
 			return;
 		}
 	} else {
 		unsigned base_found = 0;
 		unsigned char *pack, c;
 		unsigned long base_offset;
 		unsigned lo, mid, hi;

 		pack = fill(1);
 		c = *pack;
 		use(1);
 		base_offset = c & 127;
 		while (c & 128) {
 			base_offset += 1;
 			if (!base_offset || base_offset & ~(~0UL >> 7))
 				die("offset value overflow for delta base object");
 			pack = fill(1);
 			c = *pack;
 			use(1);
 			base_offset = (base_offset << 7) + (c & 127);
 		}
 		base_offset = obj_list[nr].offset - base_offset;

 		delta_data = get_data(delta_size);
 		if (dry_run || !delta_data) {
 			free(delta_data);
 			return;
 		}
 		lo = 0;
 		hi = nr;
 		while (lo < hi) {
 			mid = (lo + hi)/2;
 			if (base_offset < obj_list[mid].offset) {
 				hi = mid;
 			} else if (base_offset > obj_list[mid].offset) {
 				lo = mid + 1;
 			} else {
 				hashcpy(base_sha1, obj_list[mid].sha1);
 				base_found = !is_null_sha1(base_sha1);
 				break;
 			}
 		}
 		if (!base_found) {
 			/* The delta base object is itself a delta that
 			   has not been	resolved yet. */
 			hashcpy(obj_list[nr].sha1, null_sha1);
 			add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
 			return;
 		}
 	}

 	base = read_sha1_file(base_sha1, type, &base_size);
 	if (!base) {
 		error("failed to read delta-pack base object %s",
 		      sha1_to_hex(base_sha1));
 		if (!recover)
 			exit(1);
 		has_errors = 1;
 		return;
 	}
 	resolve_delta(nr, type, base, base_size, delta_data, delta_size);
 	free(base);
 }

 static void unpack_one(unsigned nr, unsigned total)
 {
 	unsigned shift;
 	unsigned char *pack, c;
 	unsigned long size;
 	enum object_type type;

 	obj_list[nr].offset = consumed_bytes;

 	pack = fill(1);
 	c = *pack;
 	use(1);
 	type = (c >> 4) & 7;
 	size = (c & 15);
 	shift = 4;
 	while (c & 0x80) {
 		pack = fill(1);
 		c = *pack;
 		use(1);
 		size += (c & 0x7f) << shift;
 		shift += 7;
 	}
 	if (!quiet) {
 		static unsigned long last_sec;
 		static unsigned last_percent;
 		struct timeval now;
 		unsigned percentage = ((nr+1) * 100) / total;

 		gettimeofday(&now, NULL);
 		if (percentage != last_percent || now.tv_sec != last_sec) {
 			last_sec = now.tv_sec;
 			last_percent = percentage;
 			fprintf(stderr, "%4u%% (%u/%u) done\r",
 					percentage, (nr+1), total);
 		}
 	}
 	switch (type) {
 	case OBJ_COMMIT:
 	case OBJ_TREE:
 	case OBJ_BLOB:
 	case OBJ_TAG:
 		unpack_non_delta_entry(type, size, nr);
 		return;
 	case OBJ_REF_DELTA:
 	case OBJ_OFS_DELTA:
 		unpack_delta_entry(type, size, nr);
 		return;
 	default:
 		error("bad object type %d", type);
 		has_errors = 1;
 		if (recover)
 			return;
 		exit(1);
 	}
 }

 static void unpack_all(void)
 {
 	int i;
 	struct pack_header *hdr = fill(sizeof(struct pack_header));
 	unsigned nr_objects = ntohl(hdr->hdr_entries);

 	if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
 		die("bad pack file");
 	if (!pack_version_ok(hdr->hdr_version))
 		die("unknown pack file version %d", ntohl(hdr->hdr_version));
 	fprintf(stderr, "Unpacking %d objects\n", nr_objects);

 	obj_list = xmalloc(nr_objects * sizeof(*obj_list));
 	use(sizeof(struct pack_header));
 	for (i = 0; i < nr_objects; i++)
 		unpack_one(i, nr_objects);
 	if (delta_list)
 		die("unresolved deltas left after unpacking");
 }

 int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 {
 	int i;
 	unsigned char sha1[20];

 	git_config(git_default_config);

 	quiet = !isatty(2);

 	for (i = 1 ; i < argc; i++) {
 		const char *arg = argv[i];

 		if (*arg == '-') {
 			if (!strcmp(arg, "-n")) {
 				dry_run = 1;
 				continue;
 			}
 			if (!strcmp(arg, "-q")) {
 				quiet = 1;
 				continue;
 			}
 			if (!strcmp(arg, "-r")) {
 				recover = 1;
 				continue;
 			}
 			if (!prefixcmp(arg, "--pack_header=")) {
 				struct pack_header *hdr;
 				char *c;

 				hdr = (struct pack_header *)buffer;
 				hdr->hdr_signature = htonl(PACK_SIGNATURE);
 				hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 				if (*c != ',')
 					die("bad %s", arg);
 				hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 				if (*c)
 					die("bad %s", arg);
 				len = sizeof(*hdr);
 				continue;
 			}
 			usage(unpack_usage);
 		}

 		/* We don't take any non-flag arguments now.. Maybe some day */
 		usage(unpack_usage);
 	}
 	SHA1_Init(&ctx);
 	unpack_all();
 	SHA1_Update(&ctx, buffer, offset);
 	SHA1_Final(sha1, &ctx);
 	if (hashcmp(fill(20), sha1))
 		die("final sha1 did not match");
 	use(20);

 	/* Write the last part of the buffer to stdout */
 	while (len) {
 		int ret = xwrite(1, buffer + offset, len);
 		if (ret <= 0)
 			break;
 		len -= ret;
 		offset += ret;
 	}

 	/* All done */
 	if (!quiet)
 		fprintf(stderr, "\n");
 	return has_errors;
 }
	#include "builtin.h"
	#include "cache.h"
	#include "object.h"
	#include "delta.h"
	#include "pack.h"
	#include "blob.h"
	#include "commit.h"
	#include "tag.h"
	#include "tree.h"

	static int dry_run, quiet, recover, has_errors;
	static const char unpack_usage[] = "git-unpack-objects [-n] [-q] [-r] < pack-file";

	/* We always read in 4kB chunks. */
	static unsigned char buffer[4096];
	static unsigned long offset, len, consumed_bytes;
	static SHA_CTX ctx;

	/*
	* Make sure at least "min" bytes are available in the buffer, and
	* return the pointer to the buffer.
	*/
	static void *fill(int min)
	{
	if (min <= len)
	return buffer + offset;
	if (min > sizeof(buffer))
	die("cannot fill %d bytes", min);
	if (offset) {
	SHA1_Update(&ctx, buffer, offset);
	memmove(buffer, buffer + offset, len);
	offset = 0;
	}
	do {
	int ret = xread(0, buffer + len, sizeof(buffer) - len);
	if (ret <= 0) {
	if (!ret)
	die("early EOF");
	die("read error on input: %s", strerror(errno));
	}
	len += ret;
	} while (len < min);
	return buffer;
	}

	static void use(int bytes)
	{
	if (bytes > len)
	die("used more bytes than were available");
	len -= bytes;
	offset += bytes;
	consumed_bytes += bytes;
	}

	static void *get_data(unsigned long size)
	{
	z_stream stream;
	void *buf = xmalloc(size);

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

	stream.next_out = buf;
	stream.avail_out = size;
	stream.next_in = fill(1);
	stream.avail_in = len;
	inflateInit(&stream);

	for (;;) {
	int ret = inflate(&stream, 0);
	use(len - stream.avail_in);
	if (stream.total_out == size && ret == Z_STREAM_END)
	break;
	if (ret != Z_OK) {
	error("inflate returned %d\n", ret);
	free(buf);
	buf = NULL;
	if (!recover)
	exit(1);
	has_errors = 1;
	break;
	}
	stream.next_in = fill(1);
	stream.avail_in = len;
	}
	inflateEnd(&stream);
	return buf;
	}

	struct delta_info {
	unsigned char base_sha1[20];
	unsigned long base_offset;
	unsigned long size;
	void *delta;
	unsigned nr;
	struct delta_info *next;
	};

	static struct delta_info *delta_list;

	static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
	unsigned long base_offset,
	void *delta, unsigned long size)
	{
	struct delta_info info = xmalloc(sizeof(info));

	hashcpy(info->base_sha1, base_sha1);
	info->base_offset = base_offset;
	info->size = size;
	info->delta = delta;
	info->nr = nr;
	info->next = delta_list;
	delta_list = info;
	}

	struct obj_info {
	unsigned long offset;
	unsigned char sha1[20];
	};

	static struct obj_info *obj_list;

	static void added_object(unsigned nr, const char type, void data,
	unsigned long size);

	static void write_object(unsigned nr, void *buf, unsigned long size,
	const char *type)
	{
	if (write_sha1_file(buf, size, type, obj_list[nr].sha1) < 0)
	die("failed to write object");
	added_object(nr, type, buf, size);
	}

	static void resolve_delta(unsigned nr, const char *type,
	void *base, unsigned long base_size,
	void *delta, unsigned long delta_size)
	{
	void *result;
	unsigned long result_size;

	result = patch_delta(base, base_size,
	delta, delta_size,
	&result_size);
	if (!result)
	die("failed to apply delta");
	free(delta);
	write_object(nr, result, result_size, type);
	free(result);
	}

	static void added_object(unsigned nr, const char type, void data,
	unsigned long size)
	{
	struct delta_info **p = &delta_list;
	struct delta_info *info;

	while ((info = *p) != NULL) {
	if (!hashcmp(info->base_sha1, obj_list[nr].sha1) \|\|
	info->base_offset == obj_list[nr].offset) {
	*p = info->next;
	p = &delta_list;
	resolve_delta(info->nr, type, data, size,
	info->delta, info->size);
	free(info);
	continue;
	}
	p = &info->next;
	}
	}

	static void unpack_non_delta_entry(enum object_type kind, unsigned long size,
	unsigned nr)
	{
	void *buf = get_data(size);
	const char *type;

	switch (kind) {
	case OBJ_COMMIT: type = commit_type; break;
	case OBJ_TREE: type = tree_type; break;
	case OBJ_BLOB: type = blob_type; break;
	case OBJ_TAG: type = tag_type; break;
	default: die("bad type %d", kind);
	}
	if (!dry_run && buf)
	write_object(nr, buf, size, type);
	free(buf);
	}

	static void unpack_delta_entry(enum object_type kind, unsigned long delta_size,
	unsigned nr)
	{
	void delta_data, base;
	unsigned long base_size;
	char type[20];
	unsigned char base_sha1[20];

	if (kind == OBJ_REF_DELTA) {
	hashcpy(base_sha1, fill(20));
	use(20);
	delta_data = get_data(delta_size);
	if (dry_run \|\| !delta_data) {
	free(delta_data);
	return;
	}
	if (!has_sha1_file(base_sha1)) {
	hashcpy(obj_list[nr].sha1, null_sha1);
	add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
	return;
	}
	} else {
	unsigned base_found = 0;
	unsigned char *pack, c;
	unsigned long base_offset;
	unsigned lo, mid, hi;

	pack = fill(1);
	c = *pack;
	use(1);
	base_offset = c & 127;
	while (c & 128) {
	base_offset += 1;
	if (!base_offset \|\| base_offset & ~(~0UL >> 7))
	die("offset value overflow for delta base object");
	pack = fill(1);
	c = *pack;
	use(1);
	base_offset = (base_offset << 7) + (c & 127);
	}
	base_offset = obj_list[nr].offset - base_offset;

	delta_data = get_data(delta_size);
	if (dry_run \|\| !delta_data) {
	free(delta_data);
	return;
	}
	lo = 0;
	hi = nr;
	while (lo < hi) {
	mid = (lo + hi)/2;
	if (base_offset < obj_list[mid].offset) {
	hi = mid;
	} else if (base_offset > obj_list[mid].offset) {
	lo = mid + 1;
	} else {
	hashcpy(base_sha1, obj_list[mid].sha1);
	base_found = !is_null_sha1(base_sha1);
	break;
	}
	}
	if (!base_found) {
	/* The delta base object is itself a delta that
	has not been resolved yet. */
	hashcpy(obj_list[nr].sha1, null_sha1);
	add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
	return;
	}
	}

	base = read_sha1_file(base_sha1, type, &base_size);
	if (!base) {
	error("failed to read delta-pack base object %s",
	sha1_to_hex(base_sha1));
	if (!recover)
	exit(1);
	has_errors = 1;
	return;
	}
	resolve_delta(nr, type, base, base_size, delta_data, delta_size);
	free(base);
	}

	static void unpack_one(unsigned nr, unsigned total)
	{
	unsigned shift;
	unsigned char *pack, c;
	unsigned long size;
	enum object_type type;

	obj_list[nr].offset = consumed_bytes;

	pack = fill(1);
	c = *pack;
	use(1);
	type = (c >> 4) & 7;
	size = (c & 15);
	shift = 4;
	while (c & 0x80) {
	pack = fill(1);
	c = *pack;
	use(1);
	size += (c & 0x7f) << shift;
	shift += 7;
	}
	if (!quiet) {
	static unsigned long last_sec;
	static unsigned last_percent;
	struct timeval now;
	unsigned percentage = ((nr+1) * 100) / total;

	gettimeofday(&now, NULL);
	if (percentage != last_percent \|\| now.tv_sec != last_sec) {
	last_sec = now.tv_sec;
	last_percent = percentage;
	fprintf(stderr, "%4u%% (%u/%u) done\r",
	percentage, (nr+1), total);
	}
	}
	switch (type) {
	case OBJ_COMMIT:
	case OBJ_TREE:
	case OBJ_BLOB:
	case OBJ_TAG:
	unpack_non_delta_entry(type, size, nr);
	return;
	case OBJ_REF_DELTA:
	case OBJ_OFS_DELTA:
	unpack_delta_entry(type, size, nr);
	return;
	default:
	error("bad object type %d", type);
	has_errors = 1;
	if (recover)
	return;
	exit(1);
	}
	}

	static void unpack_all(void)
	{
	int i;
	struct pack_header *hdr = fill(sizeof(struct pack_header));
	unsigned nr_objects = ntohl(hdr->hdr_entries);

	if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
	die("bad pack file");
	if (!pack_version_ok(hdr->hdr_version))
	die("unknown pack file version %d", ntohl(hdr->hdr_version));
	fprintf(stderr, "Unpacking %d objects\n", nr_objects);

	obj_list = xmalloc(nr_objects * sizeof(*obj_list));
	use(sizeof(struct pack_header));
	for (i = 0; i < nr_objects; i++)
	unpack_one(i, nr_objects);
	if (delta_list)
	die("unresolved deltas left after unpacking");
	}

	int cmd_unpack_objects(int argc, const char *argv, const char prefix)
	{
	int i;
	unsigned char sha1[20];

	git_config(git_default_config);

	quiet = !isatty(2);

	for (i = 1 ; i < argc; i++) {
	const char *arg = argv[i];

	if (*arg == '-') {
	if (!strcmp(arg, "-n")) {
	dry_run = 1;
	continue;
	}
	if (!strcmp(arg, "-q")) {
	quiet = 1;
	continue;
	}
	if (!strcmp(arg, "-r")) {
	recover = 1;
	continue;
	}
	if (!prefixcmp(arg, "--pack_header=")) {
	struct pack_header *hdr;
	char *c;

	hdr = (struct pack_header *)buffer;
	hdr->hdr_signature = htonl(PACK_SIGNATURE);
	hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
	if (*c != ',')
	die("bad %s", arg);
	hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
	if (*c)
	die("bad %s", arg);
	len = sizeof(*hdr);
	continue;
	}
	usage(unpack_usage);
	}

	/* We don't take any non-flag arguments now.. Maybe some day */
	usage(unpack_usage);
	}
	SHA1_Init(&ctx);
	unpack_all();
	SHA1_Update(&ctx, buffer, offset);
	SHA1_Final(sha1, &ctx);
	if (hashcmp(fill(20), sha1))
	die("final sha1 did not match");
	use(20);

	/* Write the last part of the buffer to stdout */
	while (len) {
	int ret = xwrite(1, buffer + offset, len);
	if (ret <= 0)
	break;
	len -= ret;
	offset += ret;
	}

	/* All done */
	if (!quiet)
	fprintf(stderr, "\n");
	return has_errors;
	}