[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)
{
	struct object_info oi = OBJECT_INFO_INIT;
	oi.sizep = &st->size;

	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
	if (!st->u.loose.mapped)
		return -1;
	switch (unpack_loose_header(&st->z, st->u.loose.mapped,
				    st->u.loose.mapsize, st->u.loose.hdr,
				    sizeof(st->u.loose.hdr), NULL)) {
	case ULHR_OK:
		break;
	case ULHR_BAD:
		goto error;
	}
	if (parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)
		goto error;

	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;
error:
	git_inflate_end(&st->z);
	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	return -1;
}


/*****************************************************************
 *
 * 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	{
ddb3474b ÆAB	226	struct object_info oi = OBJECT_INFO_INIT;
	227	oi.sizep = &st->size;
	228
c8123e72	229	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
93aa7bd5 JH	230	if (!st->u.loose.mapped)
93aa7bd5 JH	231	return -1;
3b6a8db3 ÆAB	232	switch (unpack_loose_header(&st->z, st->u.loose.mapped,
	233	st->u.loose.mapsize, st->u.loose.hdr,
	234	sizeof(st->u.loose.hdr), NULL)) {
	235	case ULHR_OK:
	236	break;
	237	case ULHR_BAD:
	238	goto error;
93aa7bd5	239	}
3b6a8db3 ÆAB	240	if (parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)
3b6a8db3 ÆAB	241	goto error;
93aa7bd5	242
93aa7bd5 JH	243	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
	244	st->u.loose.hdr_avail = st->z.total_out;
	245	st->z_state = z_used;
d4e2d15a ÆAB	246	st->close = close_istream_loose;
d4e2d15a ÆAB	247	st->read = read_istream_loose;
93aa7bd5	248
93aa7bd5	249	return 0;
3b6a8db3 ÆAB	250	error:
	251	git_inflate_end(&st->z);
	252	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	253	return -1;
46bf0438 JH	254	}
	255
	256
	257	/*****************************************************************
	258	*
	259	* Non-delta packed object stream
	260	*
	261	*****************************************************************/
	262
bc062ad0 ÆAB	263	static ssize_t read_istream_pack_non_delta(struct git_istream st, char buf,
bc062ad0 ÆAB	264	size_t sz)
7ef2d9a2 JH	265	{
	266	size_t total_read = 0;
	267
	268	switch (st->z_state) {
	269	case z_unused:
	270	memset(&st->z, 0, sizeof(st->z));
	271	git_inflate_init(&st->z);
	272	st->z_state = z_used;
	273	break;
	274	case z_done:
	275	return 0;
	276	case z_error:
	277	return -1;
	278	case z_used:
	279	break;
	280	}
	281
	282	while (total_read < sz) {
	283	int status;
	284	struct pack_window *window = NULL;
	285	unsigned char *mapped;
	286
	287	mapped = use_pack(st->u.in_pack.pack, &window,
	288	st->u.in_pack.pos, &st->z.avail_in);
	289
	290	st->z.next_out = (unsigned char *)buf + total_read;
	291	st->z.avail_out = sz - total_read;
	292	st->z.next_in = mapped;
	293	status = git_inflate(&st->z, Z_FINISH);
	294
	295	st->u.in_pack.pos += st->z.next_in - mapped;
	296	total_read = st->z.next_out - (unsigned char *)buf;
	297	unuse_pack(&window);
	298
	299	if (status == Z_STREAM_END) {
	300	git_inflate_end(&st->z);
	301	st->z_state = z_done;
	302	break;
	303	}
0afbe3e8 JK	304
	305	/*
	306	* Unlike the loose object case, we do not have to worry here
	307	* about running out of input bytes and spinning infinitely. If
	308	* we get Z_BUF_ERROR due to too few input bytes, then we'll
	309	* replenish them in the next use_pack() call when we loop. If
	310	* we truly hit the end of the pack (i.e., because it's corrupt
	311	* or truncated), then use_pack() catches that and will die().
	312	*/
7ef2d9a2 JH	313	if (status != Z_OK && status != Z_BUF_ERROR) {
	314	git_inflate_end(&st->z);
	315	st->z_state = z_error;
	316	return -1;
	317	}
	318	}
	319	return total_read;
	320	}
	321
bc062ad0	322	static int close_istream_pack_non_delta(struct git_istream *st)
7ef2d9a2 JH	323	{
	324	close_deflated_stream(st);
	325	return 0;
	326	}
	327
bc062ad0 ÆAB	328	static int open_istream_pack_non_delta(struct git_istream *st,
bc062ad0 ÆAB	329	struct repository *r,
bc062ad0 ÆAB	330	const struct object_id *oid,
bc062ad0 ÆAB	331	enum object_type *type)
46bf0438	332	{
7ef2d9a2 JH	333	struct pack_window *window;
	334	enum object_type in_pack_type;
	335
7ef2d9a2 JH	336	window = NULL;
	337
	338	in_pack_type = unpack_object_header(st->u.in_pack.pack,
	339	&window,
	340	&st->u.in_pack.pos,
	341	&st->size);
	342	unuse_pack(&window);
	343	switch (in_pack_type) {
	344	default:
	345	return -1; /* we do not do deltas for now */
	346	case OBJ_COMMIT:
	347	case OBJ_TREE:
	348	case OBJ_BLOB:
	349	case OBJ_TAG:
	350	break;
	351	}
	352	st->z_state = z_unused;
d4e2d15a ÆAB	353	st->close = close_istream_pack_non_delta;
	354	st->read = read_istream_pack_non_delta;
	355
7ef2d9a2	356	return 0;
46bf0438 JH	357	}
	358
	359
	360	/*****************************************************************
	361	*
	362	* In-core stream
	363	*
	364	*****************************************************************/
	365
bc062ad0	366	static int close_istream_incore(struct git_istream *st)
46bf0438 JH	367	{
	368	free(st->u.incore.buf);
	369	return 0;
	370	}
	371
bc062ad0	372	static ssize_t read_istream_incore(struct git_istream st, char buf, size_t sz)
46bf0438 JH	373	{
	374	size_t read_size = sz;
	375	size_t remainder = st->size - st->u.incore.read_ptr;
	376
	377	if (remainder <= read_size)
	378	read_size = remainder;
	379	if (read_size) {
	380	memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
	381	st->u.incore.read_ptr += read_size;
	382	}
	383	return read_size;
	384	}
	385
bc062ad0	386	static int open_istream_incore(struct git_istream st, struct repository r,
de94c0ea	387	const struct object_id oid, enum object_type type)
46bf0438	388	{
c8123e72	389	st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
46bf0438	390	st->u.incore.read_ptr = 0;
d4e2d15a ÆAB	391	st->close = close_istream_incore;
d4e2d15a ÆAB	392	st->read = read_istream_incore;
46bf0438 JH	393
	394	return st->u.incore.buf ? 0 : -1;
	395	}
47a02ff2	396
b6552836 ÆAB	397	/*****************************************************************************
	398	* static helpers variables and functions for users of streaming interface
	399	*****************************************************************************/
	400
d4e2d15a ÆAB	401	static int istream_source(struct git_istream *st,
	402	struct repository *r,
	403	const struct object_id *oid,
	404	enum object_type *type)
b6552836 ÆAB	405	{
	406	unsigned long size;
	407	int status;
de94c0ea	408	struct object_info oi = OBJECT_INFO_INIT;
b6552836	409
de94c0ea ÆAB	410	oi.typep = type;
	411	oi.sizep = &size;
	412	status = oid_object_info_extended(r, oid, &oi, 0);
b6552836	413	if (status < 0)
d4e2d15a	414	return status;
b6552836	415
de94c0ea	416	switch (oi.whence) {
b6552836	417	case OI_LOOSE:
d4e2d15a ÆAB	418	st->open = open_istream_loose;
d4e2d15a ÆAB	419	return 0;
b6552836	420	case OI_PACKED:
de94c0ea ÆAB	421	if (!oi.u.packed.is_delta && big_file_threshold < size) {
	422	st->u.in_pack.pack = oi.u.packed.pack;
	423	st->u.in_pack.pos = oi.u.packed.offset;
d4e2d15a ÆAB	424	st->open = open_istream_pack_non_delta;
d4e2d15a ÆAB	425	return 0;
de94c0ea	426	}
b6552836 ÆAB	427	/* fallthru */
b6552836 ÆAB	428	default:
d4e2d15a ÆAB	429	st->open = open_istream_incore;
d4e2d15a ÆAB	430	return 0;
b6552836 ÆAB	431	}
	432	}
	433
47a02ff2 JH	434	/****************************************************************
	435	* Users of streaming interface
	436	****************************************************************/
	437
b6552836 ÆAB	438	int close_istream(struct git_istream *st)
b6552836 ÆAB	439	{
d4e2d15a	440	int r = st->close(st);
b6552836 ÆAB	441	free(st);
	442	return r;
	443	}
	444
	445	ssize_t read_istream(struct git_istream st, void buf, size_t sz)
	446	{
d4e2d15a	447	return st->read(st, buf, sz);
b6552836 ÆAB	448	}
	449
	450	struct git_istream open_istream(struct repository r,
	451	const struct object_id *oid,
	452	enum object_type *type,
	453	unsigned long *size,
	454	struct stream_filter *filter)
	455	{
de94c0ea	456	struct git_istream st = xmalloc(sizeof(st));
b6552836	457	const struct object_id *real = lookup_replace_object(r, oid);
d4e2d15a	458	int ret = istream_source(st, r, real, type);
b6552836	459
d4e2d15a	460	if (ret) {
de94c0ea	461	free(st);
b6552836	462	return NULL;
de94c0ea	463	}
b6552836	464
d4e2d15a	465	if (st->open(st, r, real, type)) {
de94c0ea	466	if (open_istream_incore(st, r, real, type)) {
b6552836 ÆAB	467	free(st);
	468	return NULL;
	469	}
	470	}
	471	if (filter) {
	472	/* Add "&& !is_null_stream_filter(filter)" for performance */
	473	struct git_istream *nst = attach_stream_filter(st, filter);
	474	if (!nst) {
	475	close_istream(st);
	476	return NULL;
	477	}
	478	st = nst;
	479	}
	480
	481	*size = st->size;
	482	return st;
	483	}
	484
7eda0e4f	485	int stream_blob_to_fd(int fd, const struct object_id oid, struct stream_filter filter,
47a02ff2 JH	486	int can_seek)
	487	{
	488	struct git_istream *st;
	489	enum object_type type;
	490	unsigned long sz;
	491	ssize_t kept = 0;
	492	int result = -1;
	493
c8123e72	494	st = open_istream(the_repository, oid, &type, &sz, filter);
9ce4ad3e JK	495	if (!st) {
	496	if (filter)
	497	free_stream_filter(filter);
47a02ff2	498	return result;
9ce4ad3e	499	}
47a02ff2 JH	500	if (type != OBJ_BLOB)
	501	goto close_and_exit;
	502	for (;;) {
	503	char buf[1024 * 16];
	504	ssize_t wrote, holeto;
	505	ssize_t readlen = read_istream(st, buf, sizeof(buf));
	506
45d4bdae JK	507	if (readlen < 0)
45d4bdae JK	508	goto close_and_exit;
47a02ff2 JH	509	if (!readlen)
	510	break;
	511	if (can_seek && sizeof(buf) == readlen) {
	512	for (holeto = 0; holeto < readlen; holeto++)
	513	if (buf[holeto])
	514	break;
	515	if (readlen == holeto) {
	516	kept += holeto;
	517	continue;
	518	}
	519	}
	520
	521	if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
	522	goto close_and_exit;
	523	else
	524	kept = 0;
	525	wrote = write_in_full(fd, buf, readlen);
	526
564bde9a	527	if (wrote < 0)
47a02ff2 JH	528	goto close_and_exit;
	529	}
	530	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 \|\|
7edc02f4	531	xwrite(fd, "", 1) != 1))
47a02ff2 JH	532	goto close_and_exit;
	533	result = 0;
	534
	535	close_and_exit:
	536	close_istream(st);
	537	return result;
	538	}