[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 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 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(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(the_repository, 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(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(the_repository, oid);
	enum input_source src = istream_source(real, type, &oi);

	if (src < 0)
		return NULL;

	st = xmalloc(sizeof(*st));
	if (open_istream_tbl[src](st, &oi, real, type)) {
		if (open_istream_incore(st, &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(the_repository,
					      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(the_repository, 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(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 ,
	19	struct object_info *,
575042a0	20	const struct object_id *,
46bf0438 JH	21	enum object_type *);
	22	typedef int (close_istream_fn)(struct git_istream );
	23	typedef ssize_t (read_istream_fn)(struct git_istream , char *, size_t);
	24
	25	struct stream_vtbl {
	26	close_istream_fn close;
	27	read_istream_fn read;
	28	};
	29
	30	#define open_method_decl(name) \
	31	int open_istream_ ##name \
	32	(struct git_istream st, struct object_info oi, \
575042a0	33	const struct object_id *oid, \
46bf0438 JH	34	enum object_type *type)
	35
	36	#define close_method_decl(name) \
	37	int close_istream_ ##name \
	38	(struct git_istream *st)
	39
	40	#define read_method_decl(name) \
	41	ssize_t read_istream_ ##name \
	42	(struct git_istream st, char buf, size_t sz)
	43
	44	/* forward declaration */
	45	static open_method_decl(incore);
	46	static open_method_decl(loose);
	47	static open_method_decl(pack_non_delta);
b6691092 JH	48	static struct git_istream attach_stream_filter(struct git_istream st,
	49	struct stream_filter *filter);
	50
46bf0438 JH	51
	52	static open_istream_fn open_istream_tbl[] = {
	53	open_istream_incore,
	54	open_istream_loose,
	55	open_istream_pack_non_delta,
	56	};
	57
b6691092 JH	58	#define FILTER_BUFFER (1024*16)
	59
	60	struct filtered_istream {
	61	struct git_istream *upstream;
	62	struct stream_filter *filter;
	63	char ibuf[FILTER_BUFFER];
	64	char obuf[FILTER_BUFFER];
	65	int i_end, i_ptr;
	66	int o_end, o_ptr;
4ae66704	67	int input_finished;
b6691092 JH	68	};
b6691092 JH	69
46bf0438 JH	70	struct git_istream {
	71	const struct stream_vtbl *vtbl;
	72	unsigned long size; /* inflated size of full object */
eb4f4076	73	git_zstream z;
7ef2d9a2	74	enum { z_unused, z_used, z_done, z_error } z_state;
46bf0438 JH	75
	76	union {
	77	struct {
	78	char buf; / from read_object() */
	79	unsigned long read_ptr;
	80	} incore;
	81
	82	struct {
93aa7bd5 JH	83	void *mapped;
	84	unsigned long mapsize;
	85	char hdr[32];
	86	int hdr_avail;
	87	int hdr_used;
46bf0438 JH	88	} loose;
	89
	90	struct {
7ef2d9a2 JH	91	struct packed_git *pack;
7ef2d9a2 JH	92	off_t pos;
46bf0438	93	} in_pack;
b6691092 JH	94
b6691092 JH	95	struct filtered_istream filtered;
46bf0438 JH	96	} u;
	97	};
	98
	99	int close_istream(struct git_istream *st)
	100	{
95dea6eb JK	101	int r = st->vtbl->close(st);
	102	free(st);
	103	return r;
46bf0438 JH	104	}
46bf0438 JH	105
6163cd8a	106	ssize_t read_istream(struct git_istream st, void buf, size_t sz)
46bf0438 JH	107	{
	108	return st->vtbl->read(st, buf, sz);
	109	}
	110
b383a13c	111	static enum input_source istream_source(const struct object_id *oid,
46bf0438 JH	112	enum object_type *type,
	113	struct object_info *oi)
	114	{
	115	unsigned long size;
	116	int status;
	117
5b086407	118	oi->typep = type;
46bf0438	119	oi->sizep = &size;
7ecd8690	120	status = oid_object_info_extended(the_repository, oid, oi, 0);
46bf0438 JH	121	if (status < 0)
46bf0438 JH	122	return stream_error;
46bf0438 JH	123
	124	switch (oi->whence) {
	125	case OI_LOOSE:
	126	return loose;
	127	case OI_PACKED:
754980d0	128	if (!oi->u.packed.is_delta && big_file_threshold < size)
46bf0438 JH	129	return pack_non_delta;
	130	/* fallthru */
	131	default:
	132	return incore;
	133	}
	134	}
	135
ef7b5195	136	struct git_istream open_istream(const struct object_id oid,
46bf0438	137	enum object_type *type,
b6691092 JH	138	unsigned long *size,
b6691092 JH	139	struct stream_filter *filter)
46bf0438 JH	140	{
46bf0438 JH	141	struct git_istream *st;
27b5c1a0	142	struct object_info oi = OBJECT_INFO_INIT;
1f2e7cea	143	const struct object_id *real = lookup_replace_object(the_repository, oid);
46bf0438 JH	144	enum input_source src = istream_source(real, type, &oi);
	145
	146	if (src < 0)
	147	return NULL;
	148
	149	st = xmalloc(sizeof(*st));
b383a13c	150	if (open_istream_tbl[src](st, &oi, real, type)) {
b383a13c	151	if (open_istream_incore(st, &oi, real, type)) {
46bf0438 JH	152	free(st);
	153	return NULL;
	154	}
	155	}
6a907786	156	if (filter) {
b6691092 JH	157	/* Add "&& !is_null_stream_filter(filter)" for performance */
b6691092 JH	158	struct git_istream *nst = attach_stream_filter(st, filter);
78368f2c	159	if (!nst) {
b6691092	160	close_istream(st);
78368f2c JH	161	return NULL;
78368f2c JH	162	}
b6691092 JH	163	st = nst;
	164	}
	165
46bf0438 JH	166	*size = st->size;
	167	return st;
	168	}
	169
7ef2d9a2 JH	170
	171	/*****************************************************************
	172	*
	173	* Common helpers
	174	*
	175	*****************************************************************/
	176
	177	static void close_deflated_stream(struct git_istream *st)
	178	{
	179	if (st->z_state == z_used)
	180	git_inflate_end(&st->z);
	181	}
	182
	183
b6691092 JH	184	/*****************************************************************
	185	*
	186	* Filtered stream
	187	*
	188	*****************************************************************/
	189
	190	static close_method_decl(filtered)
	191	{
	192	free_stream_filter(st->u.filtered.filter);
	193	return close_istream(st->u.filtered.upstream);
	194	}
	195
	196	static read_method_decl(filtered)
	197	{
	198	struct filtered_istream *fs = &(st->u.filtered);
	199	size_t filled = 0;
	200
	201	while (sz) {
	202	/* do we already have filtered output? */
	203	if (fs->o_ptr < fs->o_end) {
	204	size_t to_move = fs->o_end - fs->o_ptr;
	205	if (sz < to_move)
	206	to_move = sz;
	207	memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
	208	fs->o_ptr += to_move;
	209	sz -= to_move;
	210	filled += to_move;
	211	continue;
	212	}
	213	fs->o_end = fs->o_ptr = 0;
	214
	215	/* do we have anything to feed the filter with? */
	216	if (fs->i_ptr < fs->i_end) {
	217	size_t to_feed = fs->i_end - fs->i_ptr;
	218	size_t to_receive = FILTER_BUFFER;
	219	if (stream_filter(fs->filter,
	220	fs->ibuf + fs->i_ptr, &to_feed,
	221	fs->obuf, &to_receive))
	222	return -1;
	223	fs->i_ptr = fs->i_end - to_feed;
	224	fs->o_end = FILTER_BUFFER - to_receive;
	225	continue;
	226	}
4ae66704 JH	227
	228	/* tell the filter to drain upon no more input */
	229	if (fs->input_finished) {
	230	size_t to_receive = FILTER_BUFFER;
	231	if (stream_filter(fs->filter,
	232	NULL, NULL,
	233	fs->obuf, &to_receive))
	234	return -1;
	235	fs->o_end = FILTER_BUFFER - to_receive;
	236	if (!fs->o_end)
	237	break;
	238	continue;
	239	}
b6691092 JH	240	fs->i_end = fs->i_ptr = 0;
	241
	242	/* refill the input from the upstream */
4ae66704 JH	243	if (!fs->input_finished) {
	244	fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
	245	if (fs->i_end < 0)
42e7e2a5	246	return -1;
4ae66704 JH	247	if (fs->i_end)
	248	continue;
	249	}
	250	fs->input_finished = 1;
b6691092 JH	251	}
	252	return filled;
	253	}
	254
	255	static struct stream_vtbl filtered_vtbl = {
	256	close_istream_filtered,
	257	read_istream_filtered,
	258	};
	259
	260	static struct git_istream attach_stream_filter(struct git_istream st,
	261	struct stream_filter *filter)
	262	{
	263	struct git_istream ifs = xmalloc(sizeof(ifs));
	264	struct filtered_istream *fs = &(ifs->u.filtered);
	265
	266	ifs->vtbl = &filtered_vtbl;
	267	fs->upstream = st;
	268	fs->filter = filter;
	269	fs->i_end = fs->i_ptr = 0;
	270	fs->o_end = fs->o_ptr = 0;
4ae66704	271	fs->input_finished = 0;
b6691092 JH	272	ifs->size = -1; /* unknown */
	273	return ifs;
	274	}
	275
46bf0438 JH	276	/*****************************************************************
	277	*
	278	* Loose object stream
	279	*
	280	*****************************************************************/
	281
93aa7bd5 JH	282	static read_method_decl(loose)
	283	{
	284	size_t total_read = 0;
	285
	286	switch (st->z_state) {
	287	case z_done:
	288	return 0;
	289	case z_error:
	290	return -1;
	291	default:
	292	break;
	293	}
	294
	295	if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
	296	size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
	297	if (sz < to_copy)
	298	to_copy = sz;
	299	memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
	300	st->u.loose.hdr_used += to_copy;
	301	total_read += to_copy;
	302	}
	303
	304	while (total_read < sz) {
	305	int status;
	306
	307	st->z.next_out = (unsigned char *)buf + total_read;
	308	st->z.avail_out = sz - total_read;
	309	status = git_inflate(&st->z, Z_FINISH);
	310
	311	total_read = st->z.next_out - (unsigned char *)buf;
	312
	313	if (status == Z_STREAM_END) {
	314	git_inflate_end(&st->z);
	315	st->z_state = z_done;
	316	break;
	317	}
692f0bc7	318	if (status != Z_OK && (status != Z_BUF_ERROR \|\| total_read < sz)) {
93aa7bd5 JH	319	git_inflate_end(&st->z);
	320	st->z_state = z_error;
	321	return -1;
	322	}
	323	}
	324	return total_read;
	325	}
	326
	327	static close_method_decl(loose)
	328	{
	329	close_deflated_stream(st);
	330	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	331	return 0;
	332	}
	333
	334	static struct stream_vtbl loose_vtbl = {
	335	close_istream_loose,
	336	read_istream_loose,
	337	};
	338
46bf0438 JH	339	static open_method_decl(loose)
46bf0438 JH	340	{
514c5fdd JK	341	st->u.loose.mapped = map_loose_object(the_repository,
514c5fdd JK	342	oid, &st->u.loose.mapsize);
93aa7bd5 JH	343	if (!st->u.loose.mapped)
93aa7bd5 JH	344	return -1;
00a7760e JK	345	if ((unpack_loose_header(&st->z,
	346	st->u.loose.mapped,
	347	st->u.loose.mapsize,
	348	st->u.loose.hdr,
	349	sizeof(st->u.loose.hdr)) < 0) \|\|
	350	(parse_loose_header(st->u.loose.hdr, &st->size) < 0)) {
93aa7bd5 JH	351	git_inflate_end(&st->z);
	352	munmap(st->u.loose.mapped, st->u.loose.mapsize);
	353	return -1;
	354	}
	355
93aa7bd5 JH	356	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
	357	st->u.loose.hdr_avail = st->z.total_out;
	358	st->z_state = z_used;
	359
	360	st->vtbl = &loose_vtbl;
	361	return 0;
46bf0438 JH	362	}
	363
	364
	365	/*****************************************************************
	366	*
	367	* Non-delta packed object stream
	368	*
	369	*****************************************************************/
	370
7ef2d9a2 JH	371	static read_method_decl(pack_non_delta)
	372	{
	373	size_t total_read = 0;
	374
	375	switch (st->z_state) {
	376	case z_unused:
	377	memset(&st->z, 0, sizeof(st->z));
	378	git_inflate_init(&st->z);
	379	st->z_state = z_used;
	380	break;
	381	case z_done:
	382	return 0;
	383	case z_error:
	384	return -1;
	385	case z_used:
	386	break;
	387	}
	388
	389	while (total_read < sz) {
	390	int status;
	391	struct pack_window *window = NULL;
	392	unsigned char *mapped;
	393
	394	mapped = use_pack(st->u.in_pack.pack, &window,
	395	st->u.in_pack.pos, &st->z.avail_in);
	396
	397	st->z.next_out = (unsigned char *)buf + total_read;
	398	st->z.avail_out = sz - total_read;
	399	st->z.next_in = mapped;
	400	status = git_inflate(&st->z, Z_FINISH);
	401
	402	st->u.in_pack.pos += st->z.next_in - mapped;
	403	total_read = st->z.next_out - (unsigned char *)buf;
	404	unuse_pack(&window);
	405
	406	if (status == Z_STREAM_END) {
	407	git_inflate_end(&st->z);
	408	st->z_state = z_done;
	409	break;
	410	}
0afbe3e8 JK	411
	412	/*
	413	* Unlike the loose object case, we do not have to worry here
	414	* about running out of input bytes and spinning infinitely. If
	415	* we get Z_BUF_ERROR due to too few input bytes, then we'll
	416	* replenish them in the next use_pack() call when we loop. If
	417	* we truly hit the end of the pack (i.e., because it's corrupt
	418	* or truncated), then use_pack() catches that and will die().
	419	*/
7ef2d9a2 JH	420	if (status != Z_OK && status != Z_BUF_ERROR) {
	421	git_inflate_end(&st->z);
	422	st->z_state = z_error;
	423	return -1;
	424	}
	425	}
	426	return total_read;
	427	}
	428
	429	static close_method_decl(pack_non_delta)
	430	{
	431	close_deflated_stream(st);
	432	return 0;
	433	}
	434
	435	static struct stream_vtbl pack_non_delta_vtbl = {
	436	close_istream_pack_non_delta,
	437	read_istream_pack_non_delta,
	438	};
	439
46bf0438 JH	440	static open_method_decl(pack_non_delta)
46bf0438 JH	441	{
7ef2d9a2 JH	442	struct pack_window *window;
	443	enum object_type in_pack_type;
	444
	445	st->u.in_pack.pack = oi->u.packed.pack;
	446	st->u.in_pack.pos = oi->u.packed.offset;
	447	window = NULL;
	448
	449	in_pack_type = unpack_object_header(st->u.in_pack.pack,
	450	&window,
	451	&st->u.in_pack.pos,
	452	&st->size);
	453	unuse_pack(&window);
	454	switch (in_pack_type) {
	455	default:
	456	return -1; /* we do not do deltas for now */
	457	case OBJ_COMMIT:
	458	case OBJ_TREE:
	459	case OBJ_BLOB:
	460	case OBJ_TAG:
	461	break;
	462	}
	463	st->z_state = z_unused;
	464	st->vtbl = &pack_non_delta_vtbl;
	465	return 0;
46bf0438 JH	466	}
	467
	468
	469	/*****************************************************************
	470	*
	471	* In-core stream
	472	*
	473	*****************************************************************/
	474
	475	static close_method_decl(incore)
	476	{
	477	free(st->u.incore.buf);
	478	return 0;
	479	}
	480
	481	static read_method_decl(incore)
	482	{
	483	size_t read_size = sz;
	484	size_t remainder = st->size - st->u.incore.read_ptr;
	485
	486	if (remainder <= read_size)
	487	read_size = remainder;
	488	if (read_size) {
	489	memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
	490	st->u.incore.read_ptr += read_size;
	491	}
	492	return read_size;
	493	}
	494
	495	static struct stream_vtbl incore_vtbl = {
	496	close_istream_incore,
	497	read_istream_incore,
	498	};
	499
	500	static open_method_decl(incore)
	501	{
a3b72c89	502	st->u.incore.buf = read_object_file_extended(the_repository, oid, type, &st->size, 0);
46bf0438 JH	503	st->u.incore.read_ptr = 0;
	504	st->vtbl = &incore_vtbl;
	505
	506	return st->u.incore.buf ? 0 : -1;
	507	}
47a02ff2 JH	508
	509
	510	/****************************************************************
	511	* Users of streaming interface
	512	****************************************************************/
	513
7eda0e4f	514	int stream_blob_to_fd(int fd, const struct object_id oid, struct stream_filter filter,
47a02ff2 JH	515	int can_seek)
	516	{
	517	struct git_istream *st;
	518	enum object_type type;
	519	unsigned long sz;
	520	ssize_t kept = 0;
	521	int result = -1;
	522
ef7b5195	523	st = open_istream(oid, &type, &sz, filter);
9ce4ad3e JK	524	if (!st) {
	525	if (filter)
	526	free_stream_filter(filter);
47a02ff2	527	return result;
9ce4ad3e	528	}
47a02ff2 JH	529	if (type != OBJ_BLOB)
	530	goto close_and_exit;
	531	for (;;) {
	532	char buf[1024 * 16];
	533	ssize_t wrote, holeto;
	534	ssize_t readlen = read_istream(st, buf, sizeof(buf));
	535
45d4bdae JK	536	if (readlen < 0)
45d4bdae JK	537	goto close_and_exit;
47a02ff2 JH	538	if (!readlen)
	539	break;
	540	if (can_seek && sizeof(buf) == readlen) {
	541	for (holeto = 0; holeto < readlen; holeto++)
	542	if (buf[holeto])
	543	break;
	544	if (readlen == holeto) {
	545	kept += holeto;
	546	continue;
	547	}
	548	}
	549
	550	if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
	551	goto close_and_exit;
	552	else
	553	kept = 0;
	554	wrote = write_in_full(fd, buf, readlen);
	555
564bde9a	556	if (wrote < 0)
47a02ff2 JH	557	goto close_and_exit;
	558	}
	559	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 \|\|
7edc02f4	560	xwrite(fd, "", 1) != 1))
47a02ff2 JH	561	goto close_and_exit;
	562	result = 0;
	563
	564	close_and_exit:
	565	close_istream(st);
	566	return result;
	567	}