Merge branch 'ps/object-read-stream'

The "git_istream" abstraction has been revamped to make it easier to interface with pluggable object database design. * ps/object-read-stream: streaming: drop redundant type and size pointers streaming: move into object database subsystem streaming: refactor interface to be object-database-centric streaming: move logic to read packed objects streams into backend streaming: move logic to read loose objects streams into backend streaming: make the `odb_read_stream` definition public streaming: get rid of `the_repository` streaming: rely on object sources to create object stream packfile: introduce function to read object info from a store streaming: move zlib stream into backends streaming: create structure for filtered object streams streaming: create structure for packed object streams streaming: create structure for loose object streams streaming: create structure for in-core object streams streaming: allocate stream inside the backend-specific logic streaming: explicitly pass packfile info when streaming a packed object streaming: propagate final object type via the stream streaming: drop the `open()` callback function streaming: rename `git_istream` into `odb_read_stream`
author: Junio C Hamano <gitster@pobox.com> 2025-12-16 11:08:34 +0900
committer: Junio C Hamano <gitster@pobox.com> 2025-12-16 11:08:34 +0900
commit: dbe54273a707406409fa386db5b105557b31a831 (patch)
tree: 0def4e76638eff5ca5628d3cb2d0acb157c7bf37 /streaming.c
parent: d8af7cadaa79d5837d73ec949e10b57dedb43e9b (diff)
parent: 7b940286527ec2175dffbb317f47e080bb37cf3e (diff)
download: git-dbe54273a707406409fa386db5b105557b31a831.tar.gz
1 files changed, 0 insertions, 561 deletions
diff --git a/streaming.c b/streaming.c
deleted file mode 100644
index 00ad649ae3..0000000000
--- a/streaming.c
+++ /dev/null
@@ -1,561 +0,0 @@
-/*
- * Copyright (c) 2011, Google Inc.
- */
-
-#define USE_THE_REPOSITORY_VARIABLE
-
-#include "git-compat-util.h"
-#include "convert.h"
-#include "environment.h"
-#include "streaming.h"
-#include "repository.h"
-#include "object-file.h"
-#include "odb.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 odb_read_object_info_extended() */
-			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;
-	struct odb_source *source;
-
-	oi.sizep = &st->size;
-	oi.typep = type;
-
-	odb_prepare_alternates(r->objects);
-	for (source = r->objects->sources; source; source = source->next) {
-		st->u.loose.mapped = odb_source_loose_map_object(source, oid,
-								 &st->u.loose.mapsize);
-		if (st->u.loose.mapped)
-			break;
-	}
-	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))) {
-	case ULHR_OK:
-		break;
-	case ULHR_BAD:
-	case ULHR_TOO_LONG:
-		goto error;
-	}
-	if (parse_loose_header(st->u.loose.hdr, &oi) < 0 || *type < 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 UNUSED,
-				       const struct object_id *oid UNUSED,
-				       enum object_type *type UNUSED)
-{
-	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)
-{
-	struct object_info oi = OBJECT_INFO_INIT;
-
-	st->u.incore.read_ptr = 0;
-	st->close = close_istream_incore;
-	st->read = read_istream_incore;
-
-	oi.typep = type;
-	oi.sizep = &st->size;
-	oi.contentp = (void **)&st->u.incore.buf;
-	return odb_read_object_info_extended(r->objects, oid, &oi,
-					     OBJECT_INFO_DIE_IF_CORRUPT);
-}
-
-/*****************************************************************************
- * 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 = odb_read_object_info_extended(r->objects, 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 &&
-		    repo_settings_get_big_file_threshold(the_repository) < 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;
-}
author	Junio C Hamano <gitster@pobox.com>	2025-12-16 11:08:34 +0900
committer	Junio C Hamano <gitster@pobox.com>	2025-12-16 11:08:34 +0900
commit	dbe54273a707406409fa386db5b105557b31a831 (patch)
tree	0def4e76638eff5ca5628d3cb2d0acb157c7bf37 /streaming.c
parent	d8af7cadaa79d5837d73ec949e10b57dedb43e9b (diff)
parent	7b940286527ec2175dffbb317f47e080bb37cf3e (diff)
download	git-dbe54273a707406409fa386db5b105557b31a831.tar.gz