transport-helper: drop read/write errno checks
[git.git] / streaming.c
blobac7c7a22f90b7320a235f23db9387fd91ba5b2cd
1 /*
2 * Copyright (c) 2011, Google Inc.
3 */
4 #include "cache.h"
5 #include "streaming.h"
6 #include "repository.h"
7 #include "object-store.h"
8 #include "replace-object.h"
9 #include "packfile.h"
11 enum input_source {
12 stream_error = -1,
13 incore = 0,
14 loose = 1,
15 pack_non_delta = 2
18 typedef int (*open_istream_fn)(struct git_istream *,
19 struct object_info *,
20 const struct object_id *,
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);
25 struct stream_vtbl {
26 close_istream_fn close;
27 read_istream_fn read;
30 #define open_method_decl(name) \
31 int open_istream_ ##name \
32 (struct git_istream *st, struct object_info *oi, \
33 const struct object_id *oid, \
34 enum object_type *type)
36 #define close_method_decl(name) \
37 int close_istream_ ##name \
38 (struct git_istream *st)
40 #define read_method_decl(name) \
41 ssize_t read_istream_ ##name \
42 (struct git_istream *st, char *buf, size_t sz)
44 /* forward declaration */
45 static open_method_decl(incore);
46 static open_method_decl(loose);
47 static open_method_decl(pack_non_delta);
48 static struct git_istream *attach_stream_filter(struct git_istream *st,
49 struct stream_filter *filter);
52 static open_istream_fn open_istream_tbl[] = {
53 open_istream_incore,
54 open_istream_loose,
55 open_istream_pack_non_delta,
58 #define FILTER_BUFFER (1024*16)
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;
67 int input_finished;
70 struct git_istream {
71 const struct stream_vtbl *vtbl;
72 unsigned long size; /* inflated size of full object */
73 git_zstream z;
74 enum { z_unused, z_used, z_done, z_error } z_state;
76 union {
77 struct {
78 char *buf; /* from read_object() */
79 unsigned long read_ptr;
80 } incore;
82 struct {
83 void *mapped;
84 unsigned long mapsize;
85 char hdr[32];
86 int hdr_avail;
87 int hdr_used;
88 } loose;
90 struct {
91 struct packed_git *pack;
92 off_t pos;
93 } in_pack;
95 struct filtered_istream filtered;
96 } u;
99 int close_istream(struct git_istream *st)
101 int r = st->vtbl->close(st);
102 free(st);
103 return r;
106 ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
108 return st->vtbl->read(st, buf, sz);
111 static enum input_source istream_source(const struct object_id *oid,
112 enum object_type *type,
113 struct object_info *oi)
115 unsigned long size;
116 int status;
118 oi->typep = type;
119 oi->sizep = &size;
120 status = oid_object_info_extended(the_repository, oid, oi, 0);
121 if (status < 0)
122 return stream_error;
124 switch (oi->whence) {
125 case OI_LOOSE:
126 return loose;
127 case OI_PACKED:
128 if (!oi->u.packed.is_delta && big_file_threshold < size)
129 return pack_non_delta;
130 /* fallthru */
131 default:
132 return incore;
136 struct git_istream *open_istream(const struct object_id *oid,
137 enum object_type *type,
138 unsigned long *size,
139 struct stream_filter *filter)
141 struct git_istream *st;
142 struct object_info oi = OBJECT_INFO_INIT;
143 const struct object_id *real = lookup_replace_object(the_repository, oid);
144 enum input_source src = istream_source(real, type, &oi);
146 if (src < 0)
147 return NULL;
149 st = xmalloc(sizeof(*st));
150 if (open_istream_tbl[src](st, &oi, real, type)) {
151 if (open_istream_incore(st, &oi, real, type)) {
152 free(st);
153 return NULL;
156 if (filter) {
157 /* Add "&& !is_null_stream_filter(filter)" for performance */
158 struct git_istream *nst = attach_stream_filter(st, filter);
159 if (!nst) {
160 close_istream(st);
161 return NULL;
163 st = nst;
166 *size = st->size;
167 return st;
171 /*****************************************************************
173 * Common helpers
175 *****************************************************************/
177 static void close_deflated_stream(struct git_istream *st)
179 if (st->z_state == z_used)
180 git_inflate_end(&st->z);
184 /*****************************************************************
186 * Filtered stream
188 *****************************************************************/
190 static close_method_decl(filtered)
192 free_stream_filter(st->u.filtered.filter);
193 return close_istream(st->u.filtered.upstream);
196 static read_method_decl(filtered)
198 struct filtered_istream *fs = &(st->u.filtered);
199 size_t filled = 0;
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;
213 fs->o_end = fs->o_ptr = 0;
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;
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;
240 fs->i_end = fs->i_ptr = 0;
242 /* refill the input from the upstream */
243 if (!fs->input_finished) {
244 fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
245 if (fs->i_end < 0)
246 return -1;
247 if (fs->i_end)
248 continue;
250 fs->input_finished = 1;
252 return filled;
255 static struct stream_vtbl filtered_vtbl = {
256 close_istream_filtered,
257 read_istream_filtered,
260 static struct git_istream *attach_stream_filter(struct git_istream *st,
261 struct stream_filter *filter)
263 struct git_istream *ifs = xmalloc(sizeof(*ifs));
264 struct filtered_istream *fs = &(ifs->u.filtered);
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;
271 fs->input_finished = 0;
272 ifs->size = -1; /* unknown */
273 return ifs;
276 /*****************************************************************
278 * Loose object stream
280 *****************************************************************/
282 static read_method_decl(loose)
284 size_t total_read = 0;
286 switch (st->z_state) {
287 case z_done:
288 return 0;
289 case z_error:
290 return -1;
291 default:
292 break;
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;
304 while (total_read < sz) {
305 int status;
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);
311 total_read = st->z.next_out - (unsigned char *)buf;
313 if (status == Z_STREAM_END) {
314 git_inflate_end(&st->z);
315 st->z_state = z_done;
316 break;
318 if (status != Z_OK && (status != Z_BUF_ERROR || total_read < sz)) {
319 git_inflate_end(&st->z);
320 st->z_state = z_error;
321 return -1;
324 return total_read;
327 static close_method_decl(loose)
329 close_deflated_stream(st);
330 munmap(st->u.loose.mapped, st->u.loose.mapsize);
331 return 0;
334 static struct stream_vtbl loose_vtbl = {
335 close_istream_loose,
336 read_istream_loose,
339 static open_method_decl(loose)
341 st->u.loose.mapped = map_sha1_file(the_repository,
342 oid->hash, &st->u.loose.mapsize);
343 if (!st->u.loose.mapped)
344 return -1;
345 if ((unpack_sha1_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_sha1_header(st->u.loose.hdr, &st->size) < 0)) {
351 git_inflate_end(&st->z);
352 munmap(st->u.loose.mapped, st->u.loose.mapsize);
353 return -1;
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;
360 st->vtbl = &loose_vtbl;
361 return 0;
365 /*****************************************************************
367 * Non-delta packed object stream
369 *****************************************************************/
371 static read_method_decl(pack_non_delta)
373 size_t total_read = 0;
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;
389 while (total_read < sz) {
390 int status;
391 struct pack_window *window = NULL;
392 unsigned char *mapped;
394 mapped = use_pack(st->u.in_pack.pack, &window,
395 st->u.in_pack.pos, &st->z.avail_in);
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);
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);
406 if (status == Z_STREAM_END) {
407 git_inflate_end(&st->z);
408 st->z_state = z_done;
409 break;
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().
420 if (status != Z_OK && status != Z_BUF_ERROR) {
421 git_inflate_end(&st->z);
422 st->z_state = z_error;
423 return -1;
426 return total_read;
429 static close_method_decl(pack_non_delta)
431 close_deflated_stream(st);
432 return 0;
435 static struct stream_vtbl pack_non_delta_vtbl = {
436 close_istream_pack_non_delta,
437 read_istream_pack_non_delta,
440 static open_method_decl(pack_non_delta)
442 struct pack_window *window;
443 enum object_type in_pack_type;
445 st->u.in_pack.pack = oi->u.packed.pack;
446 st->u.in_pack.pos = oi->u.packed.offset;
447 window = NULL;
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;
463 st->z_state = z_unused;
464 st->vtbl = &pack_non_delta_vtbl;
465 return 0;
469 /*****************************************************************
471 * In-core stream
473 *****************************************************************/
475 static close_method_decl(incore)
477 free(st->u.incore.buf);
478 return 0;
481 static read_method_decl(incore)
483 size_t read_size = sz;
484 size_t remainder = st->size - st->u.incore.read_ptr;
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;
492 return read_size;
495 static struct stream_vtbl incore_vtbl = {
496 close_istream_incore,
497 read_istream_incore,
500 static open_method_decl(incore)
502 st->u.incore.buf = read_object_file_extended(oid, type, &st->size, 0);
503 st->u.incore.read_ptr = 0;
504 st->vtbl = &incore_vtbl;
506 return st->u.incore.buf ? 0 : -1;
510 /****************************************************************
511 * Users of streaming interface
512 ****************************************************************/
514 int stream_blob_to_fd(int fd, const struct object_id *oid, struct stream_filter *filter,
515 int can_seek)
517 struct git_istream *st;
518 enum object_type type;
519 unsigned long sz;
520 ssize_t kept = 0;
521 int result = -1;
523 st = open_istream(oid, &type, &sz, filter);
524 if (!st) {
525 if (filter)
526 free_stream_filter(filter);
527 return result;
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));
536 if (readlen < 0)
537 goto close_and_exit;
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;
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);
556 if (wrote < 0)
557 goto close_and_exit;
559 if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
560 xwrite(fd, "", 1) != 1))
561 goto close_and_exit;
562 result = 0;
564 close_and_exit:
565 close_istream(st);
566 return result;