[thirdparty/git.git] / streaming.c

/*
 * Copyright (c) 2011, Google Inc.
 */
#include "cache.h"
#include "streaming.h"
#include "repository.h"
#include "object-store.h"
#include "replace-object.h"
#include "packfile.h"

typedef int (*open_istream_fn)(struct git_istream *,
			       struct repository *,
			       const struct object_id *,
			       enum object_type *);
typedef int (*close_istream_fn)(struct git_istream *);
typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);

#define FILTER_BUFFER (1024*16)

struct filtered_istream {
	struct git_istream *upstream;
	struct stream_filter *filter;
	char ibuf[FILTER_BUFFER];
	char obuf[FILTER_BUFFER];
	int i_end, i_ptr;
	int o_end, o_ptr;
	int input_finished;
};

struct git_istream {
	open_istream_fn open;
	close_istream_fn close;
	read_istream_fn read;

	unsigned long size; /* inflated size of full object */
	git_zstream z;
	enum { z_unused, z_used, z_done, z_error } z_state;

	union {
		struct {
			char *buf; /* from read_object() */
			unsigned long read_ptr;
		} incore;

		struct {
			void *mapped;
			unsigned long mapsize;
			char hdr[32];
			int hdr_avail;
			int hdr_used;
		} loose;

		struct {
			struct packed_git *pack;
			off_t pos;
		} in_pack;

		struct filtered_istream filtered;
	} u;
};

/*****************************************************************
 *
 * Common helpers
 *
 *****************************************************************/

static void close_deflated_stream(struct git_istream *st)
{
	if (st->z_state == z_used)
		git_inflate_end(&st->z);
}


/*****************************************************************
 *
 * Filtered stream
 *
 *****************************************************************/

static int close_istream_filtered(struct git_istream *st)
{
	free_stream_filter(st->u.filtered.filter);
	return close_istream(st->u.filtered.upstream);
}

static ssize_t read_istream_filtered(struct git_istream *st, char *buf,
				     size_t sz)
{
	struct filtered_istream *fs = &(st->u.filtered);
	size_t filled = 0;

	while (sz) {
		/* do we already have filtered output? */
		if (fs->o_ptr < fs->o_end) {
			size_t to_move = fs->o_end - fs->o_ptr;
			if (sz < to_move)
				to_move = sz;
			memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
			fs->o_ptr += to_move;
			sz -= to_move;
			filled += to_move;
			continue;
		}
		fs->o_end = fs->o_ptr = 0;

		/* do we have anything to feed the filter with? */
		if (fs->i_ptr < fs->i_end) {
			size_t to_feed = fs->i_end - fs->i_ptr;
			size_t to_receive = FILTER_BUFFER;
			if (stream_filter(fs->filter,
					  fs->ibuf + fs->i_ptr, &to_feed,
					  fs->obuf, &to_receive))
				return -1;
			fs->i_ptr = fs->i_end - to_feed;
			fs->o_end = FILTER_BUFFER - to_receive;
			continue;
		}

		/* tell the filter to drain upon no more input */
		if (fs->input_finished) {
			size_t to_receive = FILTER_BUFFER;
			if (stream_filter(fs->filter,
					  NULL, NULL,
					  fs->obuf, &to_receive))
				return -1;
			fs->o_end = FILTER_BUFFER - to_receive;
			if (!fs->o_end)
				break;
			continue;
		}
		fs->i_end = fs->i_ptr = 0;

		/* refill the input from the upstream */
		if (!fs->input_finished) {
			fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
			if (fs->i_end < 0)
				return -1;
			if (fs->i_end)
				continue;
		}
		fs->input_finished = 1;
	}
	return filled;
}

static struct git_istream *attach_stream_filter(struct git_istream *st,
						struct stream_filter *filter)
{
	struct git_istream *ifs = xmalloc(sizeof(*ifs));
	struct filtered_istream *fs = &(ifs->u.filtered);

	ifs->close = close_istream_filtered;
	ifs->read = read_istream_filtered;
	fs->upstream = st;
	fs->filter = filter;
	fs->i_end = fs->i_ptr = 0;
	fs->o_end = fs->o_ptr = 0;
	fs->input_finished = 0;
	ifs->size = -1; /* unknown */
	return ifs;
}

/*****************************************************************
 *
 * Loose object stream
 *
 *****************************************************************/

static ssize_t read_istream_loose(struct git_istream *st, char *buf, size_t sz)
{
	size_t total_read = 0;

	switch (st->z_state) {
	case z_done:
		return 0;
	case z_error:
		return -1;
	default:
		break;
	}

	if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
		size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
		if (sz < to_copy)
			to_copy = sz;
		memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
		st->u.loose.hdr_used += to_copy;
		total_read += to_copy;
	}

	while (total_read < sz) {
		int status;

		st->z.next_out = (unsigned char *)buf + total_read;
		st->z.avail_out = sz - total_read;
		status = git_inflate(&st->z, Z_FINISH);

		total_read = st->z.next_out - (unsigned char *)buf;

		if (status == Z_STREAM_END) {
			git_inflate_end(&st->z);
			st->z_state = z_done;
			break;
		}
		if (status != Z_OK && (status != Z_BUF_ERROR || total_read < sz)) {
			git_inflate_end(&st->z);
			st->z_state = z_error;
			return -1;
		}
	}
	return total_read;
}

static int close_istream_loose(struct git_istream *st)
{
	close_deflated_stream(st);
	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	return 0;
}

static int open_istream_loose(struct git_istream *st, struct repository *r,
			      const struct object_id *oid,
			      enum object_type *type)
{
	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
	if (!st->u.loose.mapped)
		return -1;
	if ((unpack_loose_header(&st->z,
				 st->u.loose.mapped,
				 st->u.loose.mapsize,
				 st->u.loose.hdr,
				 sizeof(st->u.loose.hdr)) < 0) ||
	    (parse_loose_header(st->u.loose.hdr, &st->size) < 0)) {
		git_inflate_end(&st->z);
		munmap(st->u.loose.mapped, st->u.loose.mapsize);
		return -1;
	}

	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
	st->u.loose.hdr_avail = st->z.total_out;
	st->z_state = z_used;
	st->close = close_istream_loose;
	st->read = read_istream_loose;

	return 0;
}


/*****************************************************************
 *
 * Non-delta packed object stream
 *
 *****************************************************************/

static ssize_t read_istream_pack_non_delta(struct git_istream *st, char *buf,
					   size_t sz)
{
	size_t total_read = 0;

	switch (st->z_state) {
	case z_unused:
		memset(&st->z, 0, sizeof(st->z));
		git_inflate_init(&st->z);
		st->z_state = z_used;
		break;
	case z_done:
		return 0;
	case z_error:
		return -1;
	case z_used:
		break;
	}

	while (total_read < sz) {
		int status;
		struct pack_window *window = NULL;
		unsigned char *mapped;

		mapped = use_pack(st->u.in_pack.pack, &window,
				  st->u.in_pack.pos, &st->z.avail_in);

		st->z.next_out = (unsigned char *)buf + total_read;
		st->z.avail_out = sz - total_read;
		st->z.next_in = mapped;
		status = git_inflate(&st->z, Z_FINISH);

		st->u.in_pack.pos += st->z.next_in - mapped;
		total_read = st->z.next_out - (unsigned char *)buf;
		unuse_pack(&window);

		if (status == Z_STREAM_END) {
			git_inflate_end(&st->z);
			st->z_state = z_done;
			break;
		}

		/*
		 * Unlike the loose object case, we do not have to worry here
		 * about running out of input bytes and spinning infinitely. If
		 * we get Z_BUF_ERROR due to too few input bytes, then we'll
		 * replenish them in the next use_pack() call when we loop. If
		 * we truly hit the end of the pack (i.e., because it's corrupt
		 * or truncated), then use_pack() catches that and will die().
		 */
		if (status != Z_OK && status != Z_BUF_ERROR) {
			git_inflate_end(&st->z);
			st->z_state = z_error;
			return -1;
		}
	}
	return total_read;
}

static int close_istream_pack_non_delta(struct git_istream *st)
{
	close_deflated_stream(st);
	return 0;
}

static int open_istream_pack_non_delta(struct git_istream *st,
				       struct repository *r,
				       const struct object_id *oid,
				       enum object_type *type)
{
	struct pack_window *window;
	enum object_type in_pack_type;

	window = NULL;

	in_pack_type = unpack_object_header(st->u.in_pack.pack,
					    &window,
					    &st->u.in_pack.pos,
					    &st->size);
	unuse_pack(&window);
	switch (in_pack_type) {
	default:
		return -1; /* we do not do deltas for now */
	case OBJ_COMMIT:
	case OBJ_TREE:
	case OBJ_BLOB:
	case OBJ_TAG:
		break;
	}
	st->z_state = z_unused;
	st->close = close_istream_pack_non_delta;
	st->read = read_istream_pack_non_delta;

	return 0;
}


/*****************************************************************
 *
 * In-core stream
 *
 *****************************************************************/

static int close_istream_incore(struct git_istream *st)
{
	free(st->u.incore.buf);
	return 0;
}

static ssize_t read_istream_incore(struct git_istream *st, char *buf, size_t sz)
{
	size_t read_size = sz;
	size_t remainder = st->size - st->u.incore.read_ptr;

	if (remainder <= read_size)
		read_size = remainder;
	if (read_size) {
		memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
		st->u.incore.read_ptr += read_size;
	}
	return read_size;
}

static int open_istream_incore(struct git_istream *st, struct repository *r,
			       const struct object_id *oid, enum object_type *type)
{
	st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
	st->u.incore.read_ptr = 0;
	st->close = close_istream_incore;
	st->read = read_istream_incore;

	return st->u.incore.buf ? 0 : -1;
}

/*****************************************************************************
 * static helpers variables and functions for users of streaming interface
 *****************************************************************************/

static int istream_source(struct git_istream *st,
			  struct repository *r,
			  const struct object_id *oid,
			  enum object_type *type)
{
	unsigned long size;
	int status;
	struct object_info oi = OBJECT_INFO_INIT;

	oi.typep = type;
	oi.sizep = &size;
	status = oid_object_info_extended(r, oid, &oi, 0);
	if (status < 0)
		return status;

	switch (oi.whence) {
	case OI_LOOSE:
		st->open = open_istream_loose;
		return 0;
	case OI_PACKED:
		if (!oi.u.packed.is_delta && big_file_threshold < size) {
			st->u.in_pack.pack = oi.u.packed.pack;
			st->u.in_pack.pos = oi.u.packed.offset;
			st->open = open_istream_pack_non_delta;
			return 0;
		}
		/* fallthru */
	default:
		st->open = open_istream_incore;
		return 0;
	}
}

/****************************************************************
 * Users of streaming interface
 ****************************************************************/

int close_istream(struct git_istream *st)
{
	int r = st->close(st);
	free(st);
	return r;
}

ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
{
	return st->read(st, buf, sz);
}

struct git_istream *open_istream(struct repository *r,
				 const struct object_id *oid,
				 enum object_type *type,
				 unsigned long *size,
				 struct stream_filter *filter)
{
	struct git_istream *st = xmalloc(sizeof(*st));
	const struct object_id *real = lookup_replace_object(r, oid);
	int ret = istream_source(st, r, real, type);

	if (ret) {
		free(st);
		return NULL;
	}

	if (st->open(st, r, real, type)) {
		if (open_istream_incore(st, r, real, type)) {
			free(st);
			return NULL;
		}
	}
	if (filter) {
		/* Add "&& !is_null_stream_filter(filter)" for performance */
		struct git_istream *nst = attach_stream_filter(st, filter);
		if (!nst) {
			close_istream(st);
			return NULL;
		}
		st = nst;
	}

	*size = st->size;
	return st;
}

int stream_blob_to_fd(int fd, const struct object_id *oid, struct stream_filter *filter,
		      int can_seek)
{
	struct git_istream *st;
	enum object_type type;
	unsigned long sz;
	ssize_t kept = 0;
	int result = -1;

	st = open_istream(the_repository, oid, &type, &sz, filter);
	if (!st) {
		if (filter)
			free_stream_filter(filter);
		return result;
	}
	if (type != OBJ_BLOB)
		goto close_and_exit;
	for (;;) {
		char buf[1024 * 16];
		ssize_t wrote, holeto;
		ssize_t readlen = read_istream(st, buf, sizeof(buf));

		if (readlen < 0)
			goto close_and_exit;
		if (!readlen)
			break;
		if (can_seek && sizeof(buf) == readlen) {
			for (holeto = 0; holeto < readlen; holeto++)
				if (buf[holeto])
					break;
			if (readlen == holeto) {
				kept += holeto;
				continue;
			}
		}

		if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
			goto close_and_exit;
		else
			kept = 0;
		wrote = write_in_full(fd, buf, readlen);

		if (wrote < 0)
			goto close_and_exit;
	}
	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
		     xwrite(fd, "", 1) != 1))
		goto close_and_exit;
	result = 0;

 close_and_exit:
	close_istream(st);
	return result;
}
Commit	Line	Data
46bf0438 JH	1	/*
	2	* Copyright (c) 2011, Google Inc.
	3	*/
	4	#include "cache.h"
	5	#include "streaming.h"
e35454fa SB	6	#include "repository.h"
e35454fa SB	7	#include "object-store.h"
47f351e9	8	#include "replace-object.h"
84f80ad5	9	#include "packfile.h"
46bf0438	10
46bf0438	11	typedef int (open_istream_fn)(struct git_istream ,
c8123e72	12	struct repository *,
575042a0	13	const struct object_id *,
46bf0438 JH	14	enum object_type *);
	15	typedef int (close_istream_fn)(struct git_istream );
	16	typedef ssize_t (read_istream_fn)(struct git_istream , char *, size_t);
	17
b6691092 JH	18	#define FILTER_BUFFER (1024*16)
	19
	20	struct filtered_istream {
	21	struct git_istream *upstream;
	22	struct stream_filter *filter;
	23	char ibuf[FILTER_BUFFER];
	24	char obuf[FILTER_BUFFER];
	25	int i_end, i_ptr;
	26	int o_end, o_ptr;
4ae66704	27	int input_finished;
b6691092 JH	28	};
b6691092 JH	29
46bf0438	30	struct git_istream {
d4e2d15a ÆAB	31	open_istream_fn open;
	32	close_istream_fn close;
	33	read_istream_fn read;
	34
46bf0438	35	unsigned long size; /* inflated size of full object */
eb4f4076	36	git_zstream z;
7ef2d9a2	37	enum { z_unused, z_used, z_done, z_error } z_state;
46bf0438 JH	38
	39	union {
	40	struct {
	41	char buf; / from read_object() */
	42	unsigned long read_ptr;
	43	} incore;
	44
	45	struct {
93aa7bd5 JH	46	void *mapped;
	47	unsigned long mapsize;
	48	char hdr[32];
	49	int hdr_avail;
	50	int hdr_used;
46bf0438 JH	51	} loose;
	52
	53	struct {
7ef2d9a2 JH	54	struct packed_git *pack;
7ef2d9a2 JH	55	off_t pos;
46bf0438	56	} in_pack;
b6691092 JH	57
b6691092 JH	58	struct filtered_istream filtered;
46bf0438 JH	59	} u;
	60	};
	61
7ef2d9a2 JH	62	/*****************************************************************
	63	*
	64	* Common helpers
	65	*
	66	*****************************************************************/
	67
	68	static void close_deflated_stream(struct git_istream *st)
	69	{
	70	if (st->z_state == z_used)
	71	git_inflate_end(&st->z);
	72	}
	73
	74
b6691092 JH	75	/*****************************************************************
	76	*
	77	* Filtered stream
	78	*
	79	*****************************************************************/
	80
bc062ad0	81	static int close_istream_filtered(struct git_istream *st)
b6691092 JH	82	{
	83	free_stream_filter(st->u.filtered.filter);
	84	return close_istream(st->u.filtered.upstream);
	85	}
	86
bc062ad0 ÆAB	87	static ssize_t read_istream_filtered(struct git_istream st, char buf,
bc062ad0 ÆAB	88	size_t sz)
b6691092 JH	89	{
	90	struct filtered_istream *fs = &(st->u.filtered);
	91	size_t filled = 0;
	92
	93	while (sz) {
	94	/* do we already have filtered output? */
	95	if (fs->o_ptr < fs->o_end) {
	96	size_t to_move = fs->o_end - fs->o_ptr;
	97	if (sz < to_move)
	98	to_move = sz;
	99	memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
	100	fs->o_ptr += to_move;
	101	sz -= to_move;
	102	filled += to_move;
	103	continue;
	104	}
	105	fs->o_end = fs->o_ptr = 0;
	106
	107	/* do we have anything to feed the filter with? */
	108	if (fs->i_ptr < fs->i_end) {
	109	size_t to_feed = fs->i_end - fs->i_ptr;
	110	size_t to_receive = FILTER_BUFFER;
	111	if (stream_filter(fs->filter,
	112	fs->ibuf + fs->i_ptr, &to_feed,
	113	fs->obuf, &to_receive))
	114	return -1;
	115	fs->i_ptr = fs->i_end - to_feed;
	116	fs->o_end = FILTER_BUFFER - to_receive;
	117	continue;
	118	}
4ae66704 JH	119
	120	/* tell the filter to drain upon no more input */
	121	if (fs->input_finished) {
	122	size_t to_receive = FILTER_BUFFER;
	123	if (stream_filter(fs->filter,
	124	NULL, NULL,
	125	fs->obuf, &to_receive))
	126	return -1;
	127	fs->o_end = FILTER_BUFFER - to_receive;
	128	if (!fs->o_end)
	129	break;
	130	continue;
	131	}
b6691092 JH	132	fs->i_end = fs->i_ptr = 0;
	133
	134	/* refill the input from the upstream */
4ae66704 JH	135	if (!fs->input_finished) {
	136	fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
	137	if (fs->i_end < 0)
42e7e2a5	138	return -1;
4ae66704 JH	139	if (fs->i_end)
	140	continue;
	141	}
	142	fs->input_finished = 1;
b6691092 JH	143	}
	144	return filled;
	145	}
	146
b6691092 JH	147	static struct git_istream attach_stream_filter(struct git_istream st,
	148	struct stream_filter *filter)
	149	{
	150	struct git_istream ifs = xmalloc(sizeof(ifs));
	151	struct filtered_istream *fs = &(ifs->u.filtered);
	152
d4e2d15a ÆAB	153	ifs->close = close_istream_filtered;
d4e2d15a ÆAB	154	ifs->read = read_istream_filtered;
b6691092 JH	155	fs->upstream = st;
	156	fs->filter = filter;
	157	fs->i_end = fs->i_ptr = 0;
	158	fs->o_end = fs->o_ptr = 0;
4ae66704	159	fs->input_finished = 0;
b6691092 JH	160	ifs->size = -1; /* unknown */
	161	return ifs;
	162	}
	163
46bf0438 JH	164	/*****************************************************************
	165	*
	166	* Loose object stream
	167	*
	168	*****************************************************************/
	169
bc062ad0	170	static ssize_t read_istream_loose(struct git_istream st, char buf, size_t sz)
93aa7bd5 JH	171	{
	172	size_t total_read = 0;
	173
	174	switch (st->z_state) {
	175	case z_done:
	176	return 0;
	177	case z_error:
	178	return -1;
	179	default:
	180	break;
	181	}
	182
	183	if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
	184	size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
	185	if (sz < to_copy)
	186	to_copy = sz;
	187	memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
	188	st->u.loose.hdr_used += to_copy;
	189	total_read += to_copy;
	190	}
	191
	192	while (total_read < sz) {
	193	int status;
	194
	195	st->z.next_out = (unsigned char *)buf + total_read;
	196	st->z.avail_out = sz - total_read;
	197	status = git_inflate(&st->z, Z_FINISH);
	198
	199	total_read = st->z.next_out - (unsigned char *)buf;
	200
	201	if (status == Z_STREAM_END) {
	202	git_inflate_end(&st->z);
	203	st->z_state = z_done;
	204	break;
	205	}
692f0bc7	206	if (status != Z_OK && (status != Z_BUF_ERROR \|\| total_read < sz)) {
93aa7bd5 JH	207	git_inflate_end(&st->z);
	208	st->z_state = z_error;
	209	return -1;
	210	}
	211	}
	212	return total_read;
	213	}
	214
bc062ad0	215	static int close_istream_loose(struct git_istream *st)
93aa7bd5 JH	216	{
	217	close_deflated_stream(st);
	218	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	219	return 0;
	220	}
	221
bc062ad0	222	static int open_istream_loose(struct git_istream st, struct repository r,
bc062ad0 ÆAB	223	const struct object_id *oid,
bc062ad0 ÆAB	224	enum object_type *type)
46bf0438	225	{
c8123e72	226	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
93aa7bd5 JH	227	if (!st->u.loose.mapped)
93aa7bd5 JH	228	return -1;
00a7760e JK	229	if ((unpack_loose_header(&st->z,
	230	st->u.loose.mapped,
	231	st->u.loose.mapsize,
	232	st->u.loose.hdr,
	233	sizeof(st->u.loose.hdr)) < 0) \|\|
	234	(parse_loose_header(st->u.loose.hdr, &st->size) < 0)) {
93aa7bd5 JH	235	git_inflate_end(&st->z);
	236	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	237	return -1;
	238	}
	239
93aa7bd5 JH	240	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
	241	st->u.loose.hdr_avail = st->z.total_out;
	242	st->z_state = z_used;
d4e2d15a ÆAB	243	st->close = close_istream_loose;
d4e2d15a ÆAB	244	st->read = read_istream_loose;
93aa7bd5	245
93aa7bd5	246	return 0;
46bf0438 JH	247	}
	248
	249
	250	/*****************************************************************
	251	*
	252	* Non-delta packed object stream
	253	*
	254	*****************************************************************/
	255
bc062ad0 ÆAB	256	static ssize_t read_istream_pack_non_delta(struct git_istream st, char buf,
bc062ad0 ÆAB	257	size_t sz)
7ef2d9a2 JH	258	{
	259	size_t total_read = 0;
	260
	261	switch (st->z_state) {
	262	case z_unused:
	263	memset(&st->z, 0, sizeof(st->z));
	264	git_inflate_init(&st->z);
	265	st->z_state = z_used;
	266	break;
	267	case z_done:
	268	return 0;
	269	case z_error:
	270	return -1;
	271	case z_used:
	272	break;
	273	}
	274
	275	while (total_read < sz) {
	276	int status;
	277	struct pack_window *window = NULL;
	278	unsigned char *mapped;
	279
	280	mapped = use_pack(st->u.in_pack.pack, &window,
	281	st->u.in_pack.pos, &st->z.avail_in);
	282
	283	st->z.next_out = (unsigned char *)buf + total_read;
	284	st->z.avail_out = sz - total_read;
	285	st->z.next_in = mapped;
	286	status = git_inflate(&st->z, Z_FINISH);
	287
	288	st->u.in_pack.pos += st->z.next_in - mapped;
	289	total_read = st->z.next_out - (unsigned char *)buf;
	290	unuse_pack(&window);
	291
	292	if (status == Z_STREAM_END) {
	293	git_inflate_end(&st->z);
	294	st->z_state = z_done;
	295	break;
	296	}
0afbe3e8 JK	297
	298	/*
	299	* Unlike the loose object case, we do not have to worry here
	300	* about running out of input bytes and spinning infinitely. If
	301	* we get Z_BUF_ERROR due to too few input bytes, then we'll
	302	* replenish them in the next use_pack() call when we loop. If
	303	* we truly hit the end of the pack (i.e., because it's corrupt
	304	* or truncated), then use_pack() catches that and will die().
	305	*/
7ef2d9a2 JH	306	if (status != Z_OK && status != Z_BUF_ERROR) {
	307	git_inflate_end(&st->z);
	308	st->z_state = z_error;
	309	return -1;
	310	}
	311	}
	312	return total_read;
	313	}
	314
bc062ad0	315	static int close_istream_pack_non_delta(struct git_istream *st)
7ef2d9a2 JH	316	{
	317	close_deflated_stream(st);
	318	return 0;
	319	}
	320
bc062ad0 ÆAB	321	static int open_istream_pack_non_delta(struct git_istream *st,
bc062ad0 ÆAB	322	struct repository *r,
bc062ad0 ÆAB	323	const struct object_id *oid,
bc062ad0 ÆAB	324	enum object_type *type)
46bf0438	325	{
7ef2d9a2 JH	326	struct pack_window *window;
	327	enum object_type in_pack_type;
	328
7ef2d9a2 JH	329	window = NULL;
	330
	331	in_pack_type = unpack_object_header(st->u.in_pack.pack,
	332	&window,
	333	&st->u.in_pack.pos,
	334	&st->size);
	335	unuse_pack(&window);
	336	switch (in_pack_type) {
	337	default:
	338	return -1; /* we do not do deltas for now */
	339	case OBJ_COMMIT:
	340	case OBJ_TREE:
	341	case OBJ_BLOB:
	342	case OBJ_TAG:
	343	break;
	344	}
	345	st->z_state = z_unused;
d4e2d15a ÆAB	346	st->close = close_istream_pack_non_delta;
	347	st->read = read_istream_pack_non_delta;
	348
7ef2d9a2	349	return 0;
46bf0438 JH	350	}
	351
	352
	353	/*****************************************************************
	354	*
	355	* In-core stream
	356	*
	357	*****************************************************************/
	358
bc062ad0	359	static int close_istream_incore(struct git_istream *st)
46bf0438 JH	360	{
	361	free(st->u.incore.buf);
	362	return 0;
	363	}
	364
bc062ad0	365	static ssize_t read_istream_incore(struct git_istream st, char buf, size_t sz)
46bf0438 JH	366	{
	367	size_t read_size = sz;
	368	size_t remainder = st->size - st->u.incore.read_ptr;
	369
	370	if (remainder <= read_size)
	371	read_size = remainder;
	372	if (read_size) {
	373	memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
	374	st->u.incore.read_ptr += read_size;
	375	}
	376	return read_size;
	377	}
	378
bc062ad0	379	static int open_istream_incore(struct git_istream st, struct repository r,
de94c0ea	380	const struct object_id oid, enum object_type type)
46bf0438	381	{
c8123e72	382	st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
46bf0438	383	st->u.incore.read_ptr = 0;
d4e2d15a ÆAB	384	st->close = close_istream_incore;
d4e2d15a ÆAB	385	st->read = read_istream_incore;
46bf0438 JH	386
	387	return st->u.incore.buf ? 0 : -1;
	388	}
47a02ff2	389
b6552836 ÆAB	390	/*****************************************************************************
	391	* static helpers variables and functions for users of streaming interface
	392	*****************************************************************************/
	393
d4e2d15a ÆAB	394	static int istream_source(struct git_istream *st,
	395	struct repository *r,
	396	const struct object_id *oid,
	397	enum object_type *type)
b6552836 ÆAB	398	{
	399	unsigned long size;
	400	int status;
de94c0ea	401	struct object_info oi = OBJECT_INFO_INIT;
b6552836	402
de94c0ea ÆAB	403	oi.typep = type;
	404	oi.sizep = &size;
	405	status = oid_object_info_extended(r, oid, &oi, 0);
b6552836	406	if (status < 0)
d4e2d15a	407	return status;
b6552836	408
de94c0ea	409	switch (oi.whence) {
b6552836	410	case OI_LOOSE:
d4e2d15a ÆAB	411	st->open = open_istream_loose;
d4e2d15a ÆAB	412	return 0;
b6552836	413	case OI_PACKED:
de94c0ea ÆAB	414	if (!oi.u.packed.is_delta && big_file_threshold < size) {
	415	st->u.in_pack.pack = oi.u.packed.pack;
	416	st->u.in_pack.pos = oi.u.packed.offset;
d4e2d15a ÆAB	417	st->open = open_istream_pack_non_delta;
d4e2d15a ÆAB	418	return 0;
de94c0ea	419	}
b6552836 ÆAB	420	/* fallthru */
b6552836 ÆAB	421	default:
d4e2d15a ÆAB	422	st->open = open_istream_incore;
d4e2d15a ÆAB	423	return 0;
b6552836 ÆAB	424	}
	425	}
	426
47a02ff2 JH	427	/****************************************************************
	428	* Users of streaming interface
	429	****************************************************************/
	430
b6552836 ÆAB	431	int close_istream(struct git_istream *st)
b6552836 ÆAB	432	{
d4e2d15a	433	int r = st->close(st);
b6552836 ÆAB	434	free(st);
	435	return r;
	436	}
	437
	438	ssize_t read_istream(struct git_istream st, void buf, size_t sz)
	439	{
d4e2d15a	440	return st->read(st, buf, sz);
b6552836 ÆAB	441	}
	442
	443	struct git_istream open_istream(struct repository r,
	444	const struct object_id *oid,
	445	enum object_type *type,
	446	unsigned long *size,
	447	struct stream_filter *filter)
	448	{
de94c0ea	449	struct git_istream st = xmalloc(sizeof(st));
b6552836	450	const struct object_id *real = lookup_replace_object(r, oid);
d4e2d15a	451	int ret = istream_source(st, r, real, type);
b6552836	452
d4e2d15a	453	if (ret) {
de94c0ea	454	free(st);
b6552836	455	return NULL;
de94c0ea	456	}
b6552836	457
d4e2d15a	458	if (st->open(st, r, real, type)) {
de94c0ea	459	if (open_istream_incore(st, r, real, type)) {
b6552836 ÆAB	460	free(st);
	461	return NULL;
	462	}
	463	}
	464	if (filter) {
	465	/* Add "&& !is_null_stream_filter(filter)" for performance */
	466	struct git_istream *nst = attach_stream_filter(st, filter);
	467	if (!nst) {
	468	close_istream(st);
	469	return NULL;
	470	}
	471	st = nst;
	472	}
	473
	474	*size = st->size;
	475	return st;
	476	}
	477
7eda0e4f	478	int stream_blob_to_fd(int fd, const struct object_id oid, struct stream_filter filter,
47a02ff2 JH	479	int can_seek)
	480	{
	481	struct git_istream *st;
	482	enum object_type type;
	483	unsigned long sz;
	484	ssize_t kept = 0;
	485	int result = -1;
	486
c8123e72	487	st = open_istream(the_repository, oid, &type, &sz, filter);
9ce4ad3e JK	488	if (!st) {
	489	if (filter)
	490	free_stream_filter(filter);
47a02ff2	491	return result;
9ce4ad3e	492	}
47a02ff2 JH	493	if (type != OBJ_BLOB)
	494	goto close_and_exit;
	495	for (;;) {
	496	char buf[1024 * 16];
	497	ssize_t wrote, holeto;
	498	ssize_t readlen = read_istream(st, buf, sizeof(buf));
	499
45d4bdae JK	500	if (readlen < 0)
45d4bdae JK	501	goto close_and_exit;
47a02ff2 JH	502	if (!readlen)
	503	break;
	504	if (can_seek && sizeof(buf) == readlen) {
	505	for (holeto = 0; holeto < readlen; holeto++)
	506	if (buf[holeto])
	507	break;
	508	if (readlen == holeto) {
	509	kept += holeto;
	510	continue;
	511	}
	512	}
	513
	514	if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
	515	goto close_and_exit;
	516	else
	517	kept = 0;
	518	wrote = write_in_full(fd, buf, readlen);
	519
564bde9a	520	if (wrote < 0)
47a02ff2 JH	521	goto close_and_exit;
	522	}
	523	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 \|\|
7edc02f4	524	xwrite(fd, "", 1) != 1))
47a02ff2 JH	525	goto close_and_exit;
	526	result = 0;
	527
	528	close_and_exit:
	529	close_istream(st);
	530	return result;
	531	}