| /* |
| * Copyright (c) 2011, Google Inc. |
| */ |
| #include "cache.h" |
| #include "streaming.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 unsigned char *, |
| 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 unsigned char *sha1, \ |
| 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 unsigned char *sha1, |
| enum object_type *type, |
| struct object_info *oi) |
| { |
| unsigned long size; |
| int status; |
| |
| oi->typep = type; |
| oi->sizep = &size; |
| status = sha1_object_info_extended(sha1, 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 unsigned char *sha1, |
| enum object_type *type, |
| unsigned long *size, |
| struct stream_filter *filter) |
| { |
| struct git_istream *st; |
| struct object_info oi = OBJECT_INFO_INIT; |
| const unsigned char *real = lookup_replace_object(sha1); |
| 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_sha1_file(sha1, &st->u.loose.mapsize); |
| if (!st->u.loose.mapped) |
| return -1; |
| if ((unpack_sha1_header(&st->z, |
| st->u.loose.mapped, |
| st->u.loose.mapsize, |
| st->u.loose.hdr, |
| sizeof(st->u.loose.hdr)) < 0) || |
| (parse_sha1_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; |
| } |
| 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_sha1_file_extended(sha1, 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->hash, &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; |
| } |