[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"

enum input_source {
	stream_error = -1,
	incore = 0,
	loose = 1,
	pack_non_delta = 2
};

typedef int (*open_istream_fn)(struct git_istream *,
			       struct repository *,
			       struct object_info *,
			       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);

struct stream_vtbl {
	close_istream_fn close;
	read_istream_fn read;
};

#define open_method_decl(name) \
	int open_istream_ ##name \
	(struct git_istream *st, struct repository *r, \
	 struct object_info *oi, const struct object_id *oid, \
	 enum object_type *type)

#define close_method_decl(name) \
	int close_istream_ ##name \
	(struct git_istream *st)

#define read_method_decl(name) \
	ssize_t read_istream_ ##name \
	(struct git_istream *st, char *buf, size_t sz)

/* forward declaration */
static open_method_decl(incore);
static open_method_decl(loose);
static open_method_decl(pack_non_delta);
static struct git_istream *attach_stream_filter(struct git_istream *st,
						struct stream_filter *filter);


static open_istream_fn open_istream_tbl[] = {
	open_istream_incore,
	open_istream_loose,
	open_istream_pack_non_delta,
};

#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 {
	const struct stream_vtbl *vtbl;
	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;
};

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

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

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

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

	switch (oi->whence) {
	case OI_LOOSE:
		return loose;
	case OI_PACKED:
		if (!oi->u.packed.is_delta && big_file_threshold < size)
			return pack_non_delta;
		/* fallthru */
	default:
		return incore;
	}
}

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;
	struct object_info oi = OBJECT_INFO_INIT;
	const struct object_id *real = lookup_replace_object(r, oid);
	enum input_source src = istream_source(r, real, type, &oi);

	if (src < 0)
		return NULL;

	st = xmalloc(sizeof(*st));
	if (open_istream_tbl[src](st, r, &oi, real, type)) {
		if (open_istream_incore(st, r, &oi, 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;
}


/*****************************************************************
 *
 * 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 close_method_decl(filtered)
{
	free_stream_filter(st->u.filtered.filter);
	return close_istream(st->u.filtered.upstream);
}

static read_method_decl(filtered)
{
	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 stream_vtbl filtered_vtbl = {
	close_istream_filtered,
	read_istream_filtered,
};

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->vtbl = &filtered_vtbl;
	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 read_method_decl(loose)
{
	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 close_method_decl(loose)
{
	close_deflated_stream(st);
	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	return 0;
}

static struct stream_vtbl loose_vtbl = {
	close_istream_loose,
	read_istream_loose,
};

static open_method_decl(loose)
{
	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->vtbl = &loose_vtbl;
	return 0;
}


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

static read_method_decl(pack_non_delta)
{
	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 close_method_decl(pack_non_delta)
{
	close_deflated_stream(st);
	return 0;
}

static struct stream_vtbl pack_non_delta_vtbl = {
	close_istream_pack_non_delta,
	read_istream_pack_non_delta,
};

static open_method_decl(pack_non_delta)
{
	struct pack_window *window;
	enum object_type in_pack_type;

	st->u.in_pack.pack = oi->u.packed.pack;
	st->u.in_pack.pos = oi->u.packed.offset;
	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->vtbl = &pack_non_delta_vtbl;
	return 0;
}


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

static close_method_decl(incore)
{
	free(st->u.incore.buf);
	return 0;
}

static read_method_decl(incore)
{
	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 struct stream_vtbl incore_vtbl = {
	close_istream_incore,
	read_istream_incore,
};

static open_method_decl(incore)
{
	st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
	st->u.incore.read_ptr = 0;
	st->vtbl = &incore_vtbl;

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


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

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 JH	10
	11	enum input_source {
	12	stream_error = -1,
	13	incore = 0,
	14	loose = 1,
	15	pack_non_delta = 2
	16	};
	17
	18	typedef int (open_istream_fn)(struct git_istream ,
c8123e72	19	struct repository *,
46bf0438	20	struct object_info *,
575042a0	21	const struct object_id *,
46bf0438 JH	22	enum object_type *);
	23	typedef int (close_istream_fn)(struct git_istream );
	24	typedef ssize_t (read_istream_fn)(struct git_istream , char *, size_t);
	25
	26	struct stream_vtbl {
	27	close_istream_fn close;
	28	read_istream_fn read;
	29	};
	30
	31	#define open_method_decl(name) \
	32	int open_istream_ ##name \
c8123e72 MT	33	(struct git_istream st, struct repository r, \
c8123e72 MT	34	struct object_info oi, const struct object_id oid, \
46bf0438 JH	35	enum object_type *type)
	36
	37	#define close_method_decl(name) \
	38	int close_istream_ ##name \
	39	(struct git_istream *st)
	40
	41	#define read_method_decl(name) \
	42	ssize_t read_istream_ ##name \
	43	(struct git_istream st, char buf, size_t sz)
	44
	45	/* forward declaration */
	46	static open_method_decl(incore);
	47	static open_method_decl(loose);
	48	static open_method_decl(pack_non_delta);
b6691092 JH	49	static struct git_istream attach_stream_filter(struct git_istream st,
	50	struct stream_filter *filter);
	51
46bf0438 JH	52
	53	static open_istream_fn open_istream_tbl[] = {
	54	open_istream_incore,
	55	open_istream_loose,
	56	open_istream_pack_non_delta,
	57	};
	58
b6691092 JH	59	#define FILTER_BUFFER (1024*16)
	60
	61	struct filtered_istream {
	62	struct git_istream *upstream;
	63	struct stream_filter *filter;
	64	char ibuf[FILTER_BUFFER];
	65	char obuf[FILTER_BUFFER];
	66	int i_end, i_ptr;
	67	int o_end, o_ptr;
4ae66704	68	int input_finished;
b6691092 JH	69	};
b6691092 JH	70
46bf0438 JH	71	struct git_istream {
	72	const struct stream_vtbl *vtbl;
	73	unsigned long size; /* inflated size of full object */
eb4f4076	74	git_zstream z;
7ef2d9a2	75	enum { z_unused, z_used, z_done, z_error } z_state;
46bf0438 JH	76
	77	union {
	78	struct {
	79	char buf; / from read_object() */
	80	unsigned long read_ptr;
	81	} incore;
	82
	83	struct {
93aa7bd5 JH	84	void *mapped;
	85	unsigned long mapsize;
	86	char hdr[32];
	87	int hdr_avail;
	88	int hdr_used;
46bf0438 JH	89	} loose;
	90
	91	struct {
7ef2d9a2 JH	92	struct packed_git *pack;
7ef2d9a2 JH	93	off_t pos;
46bf0438	94	} in_pack;
b6691092 JH	95
b6691092 JH	96	struct filtered_istream filtered;
46bf0438 JH	97	} u;
	98	};
	99
	100	int close_istream(struct git_istream *st)
	101	{
95dea6eb JK	102	int r = st->vtbl->close(st);
	103	free(st);
	104	return r;
46bf0438 JH	105	}
46bf0438 JH	106
6163cd8a	107	ssize_t read_istream(struct git_istream st, void buf, size_t sz)
46bf0438 JH	108	{
	109	return st->vtbl->read(st, buf, sz);
	110	}
	111
c8123e72 MT	112	static enum input_source istream_source(struct repository *r,
c8123e72 MT	113	const struct object_id *oid,
46bf0438 JH	114	enum object_type *type,
	115	struct object_info *oi)
	116	{
	117	unsigned long size;
	118	int status;
	119
5b086407	120	oi->typep = type;
46bf0438	121	oi->sizep = &size;
c8123e72	122	status = oid_object_info_extended(r, oid, oi, 0);
46bf0438 JH	123	if (status < 0)
46bf0438 JH	124	return stream_error;
46bf0438 JH	125
	126	switch (oi->whence) {
	127	case OI_LOOSE:
	128	return loose;
	129	case OI_PACKED:
754980d0	130	if (!oi->u.packed.is_delta && big_file_threshold < size)
46bf0438 JH	131	return pack_non_delta;
	132	/* fallthru */
	133	default:
	134	return incore;
	135	}
	136	}
	137
c8123e72 MT	138	struct git_istream open_istream(struct repository r,
c8123e72 MT	139	const struct object_id *oid,
46bf0438	140	enum object_type *type,
b6691092 JH	141	unsigned long *size,
b6691092 JH	142	struct stream_filter *filter)
46bf0438 JH	143	{
46bf0438 JH	144	struct git_istream *st;
27b5c1a0	145	struct object_info oi = OBJECT_INFO_INIT;
c8123e72 MT	146	const struct object_id *real = lookup_replace_object(r, oid);
c8123e72 MT	147	enum input_source src = istream_source(r, real, type, &oi);
46bf0438 JH	148
	149	if (src < 0)
	150	return NULL;
	151
	152	st = xmalloc(sizeof(*st));
c8123e72 MT	153	if (open_istream_tbl[src](st, r, &oi, real, type)) {
c8123e72 MT	154	if (open_istream_incore(st, r, &oi, real, type)) {
46bf0438 JH	155	free(st);
	156	return NULL;
	157	}
	158	}
6a907786	159	if (filter) {
b6691092 JH	160	/* Add "&& !is_null_stream_filter(filter)" for performance */
b6691092 JH	161	struct git_istream *nst = attach_stream_filter(st, filter);
78368f2c	162	if (!nst) {
b6691092	163	close_istream(st);
78368f2c JH	164	return NULL;
78368f2c JH	165	}
b6691092 JH	166	st = nst;
	167	}
	168
46bf0438 JH	169	*size = st->size;
	170	return st;
	171	}
	172
7ef2d9a2 JH	173
	174	/*****************************************************************
	175	*
	176	* Common helpers
	177	*
	178	*****************************************************************/
	179
	180	static void close_deflated_stream(struct git_istream *st)
	181	{
	182	if (st->z_state == z_used)
	183	git_inflate_end(&st->z);
	184	}
	185
	186
b6691092 JH	187	/*****************************************************************
	188	*
	189	* Filtered stream
	190	*
	191	*****************************************************************/
	192
	193	static close_method_decl(filtered)
	194	{
	195	free_stream_filter(st->u.filtered.filter);
	196	return close_istream(st->u.filtered.upstream);
	197	}
	198
	199	static read_method_decl(filtered)
	200	{
	201	struct filtered_istream *fs = &(st->u.filtered);
	202	size_t filled = 0;
	203
	204	while (sz) {
	205	/* do we already have filtered output? */
	206	if (fs->o_ptr < fs->o_end) {
	207	size_t to_move = fs->o_end - fs->o_ptr;
	208	if (sz < to_move)
	209	to_move = sz;
	210	memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
	211	fs->o_ptr += to_move;
	212	sz -= to_move;
	213	filled += to_move;
	214	continue;
	215	}
	216	fs->o_end = fs->o_ptr = 0;
	217
	218	/* do we have anything to feed the filter with? */
	219	if (fs->i_ptr < fs->i_end) {
	220	size_t to_feed = fs->i_end - fs->i_ptr;
	221	size_t to_receive = FILTER_BUFFER;
	222	if (stream_filter(fs->filter,
	223	fs->ibuf + fs->i_ptr, &to_feed,
	224	fs->obuf, &to_receive))
	225	return -1;
	226	fs->i_ptr = fs->i_end - to_feed;
	227	fs->o_end = FILTER_BUFFER - to_receive;
	228	continue;
	229	}
4ae66704 JH	230
	231	/* tell the filter to drain upon no more input */
	232	if (fs->input_finished) {
	233	size_t to_receive = FILTER_BUFFER;
	234	if (stream_filter(fs->filter,
	235	NULL, NULL,
	236	fs->obuf, &to_receive))
	237	return -1;
	238	fs->o_end = FILTER_BUFFER - to_receive;
	239	if (!fs->o_end)
	240	break;
	241	continue;
	242	}
b6691092 JH	243	fs->i_end = fs->i_ptr = 0;
	244
	245	/* refill the input from the upstream */
4ae66704 JH	246	if (!fs->input_finished) {
	247	fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
	248	if (fs->i_end < 0)
42e7e2a5	249	return -1;
4ae66704 JH	250	if (fs->i_end)
	251	continue;
	252	}
	253	fs->input_finished = 1;
b6691092 JH	254	}
	255	return filled;
	256	}
	257
	258	static struct stream_vtbl filtered_vtbl = {
	259	close_istream_filtered,
	260	read_istream_filtered,
	261	};
	262
	263	static struct git_istream attach_stream_filter(struct git_istream st,
	264	struct stream_filter *filter)
	265	{
	266	struct git_istream ifs = xmalloc(sizeof(ifs));
	267	struct filtered_istream *fs = &(ifs->u.filtered);
	268
	269	ifs->vtbl = &filtered_vtbl;
	270	fs->upstream = st;
	271	fs->filter = filter;
	272	fs->i_end = fs->i_ptr = 0;
	273	fs->o_end = fs->o_ptr = 0;
4ae66704	274	fs->input_finished = 0;
b6691092 JH	275	ifs->size = -1; /* unknown */
	276	return ifs;
	277	}
	278
46bf0438 JH	279	/*****************************************************************
	280	*
	281	* Loose object stream
	282	*
	283	*****************************************************************/
	284
93aa7bd5 JH	285	static read_method_decl(loose)
	286	{
	287	size_t total_read = 0;
	288
	289	switch (st->z_state) {
	290	case z_done:
	291	return 0;
	292	case z_error:
	293	return -1;
	294	default:
	295	break;
	296	}
	297
	298	if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
	299	size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
	300	if (sz < to_copy)
	301	to_copy = sz;
	302	memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
	303	st->u.loose.hdr_used += to_copy;
	304	total_read += to_copy;
	305	}
	306
	307	while (total_read < sz) {
	308	int status;
	309
	310	st->z.next_out = (unsigned char *)buf + total_read;
	311	st->z.avail_out = sz - total_read;
	312	status = git_inflate(&st->z, Z_FINISH);
	313
	314	total_read = st->z.next_out - (unsigned char *)buf;
	315
	316	if (status == Z_STREAM_END) {
	317	git_inflate_end(&st->z);
	318	st->z_state = z_done;
	319	break;
	320	}
692f0bc7	321	if (status != Z_OK && (status != Z_BUF_ERROR \|\| total_read < sz)) {
93aa7bd5 JH	322	git_inflate_end(&st->z);
	323	st->z_state = z_error;
	324	return -1;
	325	}
	326	}
	327	return total_read;
	328	}
	329
	330	static close_method_decl(loose)
	331	{
	332	close_deflated_stream(st);
	333	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	334	return 0;
	335	}
	336
	337	static struct stream_vtbl loose_vtbl = {
	338	close_istream_loose,
	339	read_istream_loose,
	340	};
	341
46bf0438 JH	342	static open_method_decl(loose)
46bf0438 JH	343	{
c8123e72	344	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
93aa7bd5 JH	345	if (!st->u.loose.mapped)
93aa7bd5 JH	346	return -1;
00a7760e JK	347	if ((unpack_loose_header(&st->z,
	348	st->u.loose.mapped,
	349	st->u.loose.mapsize,
	350	st->u.loose.hdr,
	351	sizeof(st->u.loose.hdr)) < 0) \|\|
	352	(parse_loose_header(st->u.loose.hdr, &st->size) < 0)) {
93aa7bd5 JH	353	git_inflate_end(&st->z);
	354	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	355	return -1;
	356	}
	357
93aa7bd5 JH	358	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
	359	st->u.loose.hdr_avail = st->z.total_out;
	360	st->z_state = z_used;
	361
	362	st->vtbl = &loose_vtbl;
	363	return 0;
46bf0438 JH	364	}
	365
	366
	367	/*****************************************************************
	368	*
	369	* Non-delta packed object stream
	370	*
	371	*****************************************************************/
	372
7ef2d9a2 JH	373	static read_method_decl(pack_non_delta)
	374	{
	375	size_t total_read = 0;
	376
	377	switch (st->z_state) {
	378	case z_unused:
	379	memset(&st->z, 0, sizeof(st->z));
	380	git_inflate_init(&st->z);
	381	st->z_state = z_used;
	382	break;
	383	case z_done:
	384	return 0;
	385	case z_error:
	386	return -1;
	387	case z_used:
	388	break;
	389	}
	390
	391	while (total_read < sz) {
	392	int status;
	393	struct pack_window *window = NULL;
	394	unsigned char *mapped;
	395
	396	mapped = use_pack(st->u.in_pack.pack, &window,
	397	st->u.in_pack.pos, &st->z.avail_in);
	398
	399	st->z.next_out = (unsigned char *)buf + total_read;
	400	st->z.avail_out = sz - total_read;
	401	st->z.next_in = mapped;
	402	status = git_inflate(&st->z, Z_FINISH);
	403
	404	st->u.in_pack.pos += st->z.next_in - mapped;
	405	total_read = st->z.next_out - (unsigned char *)buf;
	406	unuse_pack(&window);
	407
	408	if (status == Z_STREAM_END) {
	409	git_inflate_end(&st->z);
	410	st->z_state = z_done;
	411	break;
	412	}
0afbe3e8 JK	413
	414	/*
	415	* Unlike the loose object case, we do not have to worry here
	416	* about running out of input bytes and spinning infinitely. If
	417	* we get Z_BUF_ERROR due to too few input bytes, then we'll
	418	* replenish them in the next use_pack() call when we loop. If
	419	* we truly hit the end of the pack (i.e., because it's corrupt
	420	* or truncated), then use_pack() catches that and will die().
	421	*/
7ef2d9a2 JH	422	if (status != Z_OK && status != Z_BUF_ERROR) {
	423	git_inflate_end(&st->z);
	424	st->z_state = z_error;
	425	return -1;
	426	}
	427	}
	428	return total_read;
	429	}
	430
	431	static close_method_decl(pack_non_delta)
	432	{
	433	close_deflated_stream(st);
	434	return 0;
	435	}
	436
	437	static struct stream_vtbl pack_non_delta_vtbl = {
	438	close_istream_pack_non_delta,
	439	read_istream_pack_non_delta,
	440	};
	441
46bf0438 JH	442	static open_method_decl(pack_non_delta)
46bf0438 JH	443	{
7ef2d9a2 JH	444	struct pack_window *window;
	445	enum object_type in_pack_type;
	446
	447	st->u.in_pack.pack = oi->u.packed.pack;
	448	st->u.in_pack.pos = oi->u.packed.offset;
	449	window = NULL;
	450
	451	in_pack_type = unpack_object_header(st->u.in_pack.pack,
	452	&window,
	453	&st->u.in_pack.pos,
	454	&st->size);
	455	unuse_pack(&window);
	456	switch (in_pack_type) {
	457	default:
	458	return -1; /* we do not do deltas for now */
	459	case OBJ_COMMIT:
	460	case OBJ_TREE:
	461	case OBJ_BLOB:
	462	case OBJ_TAG:
	463	break;
	464	}
	465	st->z_state = z_unused;
	466	st->vtbl = &pack_non_delta_vtbl;
	467	return 0;
46bf0438 JH	468	}
	469
	470
	471	/*****************************************************************
	472	*
	473	* In-core stream
	474	*
	475	*****************************************************************/
	476
	477	static close_method_decl(incore)
	478	{
	479	free(st->u.incore.buf);
	480	return 0;
	481	}
	482
	483	static read_method_decl(incore)
	484	{
	485	size_t read_size = sz;
	486	size_t remainder = st->size - st->u.incore.read_ptr;
	487
	488	if (remainder <= read_size)
	489	read_size = remainder;
	490	if (read_size) {
	491	memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
	492	st->u.incore.read_ptr += read_size;
	493	}
	494	return read_size;
	495	}
	496
	497	static struct stream_vtbl incore_vtbl = {
	498	close_istream_incore,
	499	read_istream_incore,
	500	};
	501
	502	static open_method_decl(incore)
	503	{
c8123e72	504	st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
46bf0438 JH	505	st->u.incore.read_ptr = 0;
	506	st->vtbl = &incore_vtbl;
	507
	508	return st->u.incore.buf ? 0 : -1;
	509	}
47a02ff2 JH	510
	511
	512	/****************************************************************
	513	* Users of streaming interface
	514	****************************************************************/
	515
7eda0e4f	516	int stream_blob_to_fd(int fd, const struct object_id oid, struct stream_filter filter,
47a02ff2 JH	517	int can_seek)
	518	{
	519	struct git_istream *st;
	520	enum object_type type;
	521	unsigned long sz;
	522	ssize_t kept = 0;
	523	int result = -1;
	524
c8123e72	525	st = open_istream(the_repository, oid, &type, &sz, filter);
9ce4ad3e JK	526	if (!st) {
	527	if (filter)
	528	free_stream_filter(filter);
47a02ff2	529	return result;
9ce4ad3e	530	}
47a02ff2 JH	531	if (type != OBJ_BLOB)
	532	goto close_and_exit;
	533	for (;;) {
	534	char buf[1024 * 16];
	535	ssize_t wrote, holeto;
	536	ssize_t readlen = read_istream(st, buf, sizeof(buf));
	537
45d4bdae JK	538	if (readlen < 0)
45d4bdae JK	539	goto close_and_exit;
47a02ff2 JH	540	if (!readlen)
	541	break;
	542	if (can_seek && sizeof(buf) == readlen) {
	543	for (holeto = 0; holeto < readlen; holeto++)
	544	if (buf[holeto])
	545	break;
	546	if (readlen == holeto) {
	547	kept += holeto;
	548	continue;
	549	}
	550	}
	551
	552	if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
	553	goto close_and_exit;
	554	else
	555	kept = 0;
	556	wrote = write_in_full(fd, buf, readlen);
	557
564bde9a	558	if (wrote < 0)
47a02ff2 JH	559	goto close_and_exit;
	560	}
	561	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 \|\|
7edc02f4	562	xwrite(fd, "", 1) != 1))
47a02ff2 JH	563	goto close_and_exit;
	564	result = 0;
	565
	566	close_and_exit:
	567	close_istream(st);
	568	return result;
	569	}