7d55ba64c7551de0f3be1dfcf56cd3344ebd8f59
[git/git.git] / streaming.c
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 "packfile.h"
9
10 enum input_source {
11 stream_error = -1,
12 incore = 0,
13 loose = 1,
14 pack_non_delta = 2
15 };
16
17 typedef int (*open_istream_fn)(struct git_istream *,
18 struct object_info *,
19 const struct object_id *,
20 enum object_type *);
21 typedef int (*close_istream_fn)(struct git_istream *);
22 typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);
23
24 struct stream_vtbl {
25 close_istream_fn close;
26 read_istream_fn read;
27 };
28
29 #define open_method_decl(name) \
30 int open_istream_ ##name \
31 (struct git_istream *st, struct object_info *oi, \
32 const struct object_id *oid, \
33 enum object_type *type)
34
35 #define close_method_decl(name) \
36 int close_istream_ ##name \
37 (struct git_istream *st)
38
39 #define read_method_decl(name) \
40 ssize_t read_istream_ ##name \
41 (struct git_istream *st, char *buf, size_t sz)
42
43 /* forward declaration */
44 static open_method_decl(incore);
45 static open_method_decl(loose);
46 static open_method_decl(pack_non_delta);
47 static struct git_istream *attach_stream_filter(struct git_istream *st,
48 struct stream_filter *filter);
49
50
51 static open_istream_fn open_istream_tbl[] = {
52 open_istream_incore,
53 open_istream_loose,
54 open_istream_pack_non_delta,
55 };
56
57 #define FILTER_BUFFER (1024*16)
58
59 struct filtered_istream {
60 struct git_istream *upstream;
61 struct stream_filter *filter;
62 char ibuf[FILTER_BUFFER];
63 char obuf[FILTER_BUFFER];
64 int i_end, i_ptr;
65 int o_end, o_ptr;
66 int input_finished;
67 };
68
69 struct git_istream {
70 const struct stream_vtbl *vtbl;
71 unsigned long size; /* inflated size of full object */
72 git_zstream z;
73 enum { z_unused, z_used, z_done, z_error } z_state;
74
75 union {
76 struct {
77 char *buf; /* from read_object() */
78 unsigned long read_ptr;
79 } incore;
80
81 struct {
82 void *mapped;
83 unsigned long mapsize;
84 char hdr[32];
85 int hdr_avail;
86 int hdr_used;
87 } loose;
88
89 struct {
90 struct packed_git *pack;
91 off_t pos;
92 } in_pack;
93
94 struct filtered_istream filtered;
95 } u;
96 };
97
98 int close_istream(struct git_istream *st)
99 {
100 int r = st->vtbl->close(st);
101 free(st);
102 return r;
103 }
104
105 ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
106 {
107 return st->vtbl->read(st, buf, sz);
108 }
109
110 static enum input_source istream_source(const struct object_id *oid,
111 enum object_type *type,
112 struct object_info *oi)
113 {
114 unsigned long size;
115 int status;
116
117 oi->typep = type;
118 oi->sizep = &size;
119 status = oid_object_info_extended(oid, oi, 0);
120 if (status < 0)
121 return stream_error;
122
123 switch (oi->whence) {
124 case OI_LOOSE:
125 return loose;
126 case OI_PACKED:
127 if (!oi->u.packed.is_delta && big_file_threshold < size)
128 return pack_non_delta;
129 /* fallthru */
130 default:
131 return incore;
132 }
133 }
134
135 struct git_istream *open_istream(const struct object_id *oid,
136 enum object_type *type,
137 unsigned long *size,
138 struct stream_filter *filter)
139 {
140 struct git_istream *st;
141 struct object_info oi = OBJECT_INFO_INIT;
142 const struct object_id *real = lookup_replace_object(oid);
143 enum input_source src = istream_source(real, type, &oi);
144
145 if (src < 0)
146 return NULL;
147
148 st = xmalloc(sizeof(*st));
149 if (open_istream_tbl[src](st, &oi, real, type)) {
150 if (open_istream_incore(st, &oi, real, type)) {
151 free(st);
152 return NULL;
153 }
154 }
155 if (filter) {
156 /* Add "&& !is_null_stream_filter(filter)" for performance */
157 struct git_istream *nst = attach_stream_filter(st, filter);
158 if (!nst) {
159 close_istream(st);
160 return NULL;
161 }
162 st = nst;
163 }
164
165 *size = st->size;
166 return st;
167 }
168
169
170 /*****************************************************************
171 *
172 * Common helpers
173 *
174 *****************************************************************/
175
176 static void close_deflated_stream(struct git_istream *st)
177 {
178 if (st->z_state == z_used)
179 git_inflate_end(&st->z);
180 }
181
182
183 /*****************************************************************
184 *
185 * Filtered stream
186 *
187 *****************************************************************/
188
189 static close_method_decl(filtered)
190 {
191 free_stream_filter(st->u.filtered.filter);
192 return close_istream(st->u.filtered.upstream);
193 }
194
195 static read_method_decl(filtered)
196 {
197 struct filtered_istream *fs = &(st->u.filtered);
198 size_t filled = 0;
199
200 while (sz) {
201 /* do we already have filtered output? */
202 if (fs->o_ptr < fs->o_end) {
203 size_t to_move = fs->o_end - fs->o_ptr;
204 if (sz < to_move)
205 to_move = sz;
206 memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
207 fs->o_ptr += to_move;
208 sz -= to_move;
209 filled += to_move;
210 continue;
211 }
212 fs->o_end = fs->o_ptr = 0;
213
214 /* do we have anything to feed the filter with? */
215 if (fs->i_ptr < fs->i_end) {
216 size_t to_feed = fs->i_end - fs->i_ptr;
217 size_t to_receive = FILTER_BUFFER;
218 if (stream_filter(fs->filter,
219 fs->ibuf + fs->i_ptr, &to_feed,
220 fs->obuf, &to_receive))
221 return -1;
222 fs->i_ptr = fs->i_end - to_feed;
223 fs->o_end = FILTER_BUFFER - to_receive;
224 continue;
225 }
226
227 /* tell the filter to drain upon no more input */
228 if (fs->input_finished) {
229 size_t to_receive = FILTER_BUFFER;
230 if (stream_filter(fs->filter,
231 NULL, NULL,
232 fs->obuf, &to_receive))
233 return -1;
234 fs->o_end = FILTER_BUFFER - to_receive;
235 if (!fs->o_end)
236 break;
237 continue;
238 }
239 fs->i_end = fs->i_ptr = 0;
240
241 /* refill the input from the upstream */
242 if (!fs->input_finished) {
243 fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
244 if (fs->i_end < 0)
245 return -1;
246 if (fs->i_end)
247 continue;
248 }
249 fs->input_finished = 1;
250 }
251 return filled;
252 }
253
254 static struct stream_vtbl filtered_vtbl = {
255 close_istream_filtered,
256 read_istream_filtered,
257 };
258
259 static struct git_istream *attach_stream_filter(struct git_istream *st,
260 struct stream_filter *filter)
261 {
262 struct git_istream *ifs = xmalloc(sizeof(*ifs));
263 struct filtered_istream *fs = &(ifs->u.filtered);
264
265 ifs->vtbl = &filtered_vtbl;
266 fs->upstream = st;
267 fs->filter = filter;
268 fs->i_end = fs->i_ptr = 0;
269 fs->o_end = fs->o_ptr = 0;
270 fs->input_finished = 0;
271 ifs->size = -1; /* unknown */
272 return ifs;
273 }
274
275 /*****************************************************************
276 *
277 * Loose object stream
278 *
279 *****************************************************************/
280
281 static read_method_decl(loose)
282 {
283 size_t total_read = 0;
284
285 switch (st->z_state) {
286 case z_done:
287 return 0;
288 case z_error:
289 return -1;
290 default:
291 break;
292 }
293
294 if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
295 size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
296 if (sz < to_copy)
297 to_copy = sz;
298 memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
299 st->u.loose.hdr_used += to_copy;
300 total_read += to_copy;
301 }
302
303 while (total_read < sz) {
304 int status;
305
306 st->z.next_out = (unsigned char *)buf + total_read;
307 st->z.avail_out = sz - total_read;
308 status = git_inflate(&st->z, Z_FINISH);
309
310 total_read = st->z.next_out - (unsigned char *)buf;
311
312 if (status == Z_STREAM_END) {
313 git_inflate_end(&st->z);
314 st->z_state = z_done;
315 break;
316 }
317 if (status != Z_OK && (status != Z_BUF_ERROR || total_read < sz)) {
318 git_inflate_end(&st->z);
319 st->z_state = z_error;
320 return -1;
321 }
322 }
323 return total_read;
324 }
325
326 static close_method_decl(loose)
327 {
328 close_deflated_stream(st);
329 munmap(st->u.loose.mapped, st->u.loose.mapsize);
330 return 0;
331 }
332
333 static struct stream_vtbl loose_vtbl = {
334 close_istream_loose,
335 read_istream_loose,
336 };
337
338 static open_method_decl(loose)
339 {
340 st->u.loose.mapped = map_sha1_file(the_repository,
341 oid->hash, &st->u.loose.mapsize);
342 if (!st->u.loose.mapped)
343 return -1;
344 if ((unpack_sha1_header(&st->z,
345 st->u.loose.mapped,
346 st->u.loose.mapsize,
347 st->u.loose.hdr,
348 sizeof(st->u.loose.hdr)) < 0) ||
349 (parse_sha1_header(st->u.loose.hdr, &st->size) < 0)) {
350 git_inflate_end(&st->z);
351 munmap(st->u.loose.mapped, st->u.loose.mapsize);
352 return -1;
353 }
354
355 st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
356 st->u.loose.hdr_avail = st->z.total_out;
357 st->z_state = z_used;
358
359 st->vtbl = &loose_vtbl;
360 return 0;
361 }
362
363
364 /*****************************************************************
365 *
366 * Non-delta packed object stream
367 *
368 *****************************************************************/
369
370 static read_method_decl(pack_non_delta)
371 {
372 size_t total_read = 0;
373
374 switch (st->z_state) {
375 case z_unused:
376 memset(&st->z, 0, sizeof(st->z));
377 git_inflate_init(&st->z);
378 st->z_state = z_used;
379 break;
380 case z_done:
381 return 0;
382 case z_error:
383 return -1;
384 case z_used:
385 break;
386 }
387
388 while (total_read < sz) {
389 int status;
390 struct pack_window *window = NULL;
391 unsigned char *mapped;
392
393 mapped = use_pack(st->u.in_pack.pack, &window,
394 st->u.in_pack.pos, &st->z.avail_in);
395
396 st->z.next_out = (unsigned char *)buf + total_read;
397 st->z.avail_out = sz - total_read;
398 st->z.next_in = mapped;
399 status = git_inflate(&st->z, Z_FINISH);
400
401 st->u.in_pack.pos += st->z.next_in - mapped;
402 total_read = st->z.next_out - (unsigned char *)buf;
403 unuse_pack(&window);
404
405 if (status == Z_STREAM_END) {
406 git_inflate_end(&st->z);
407 st->z_state = z_done;
408 break;
409 }
410 if (status != Z_OK && status != Z_BUF_ERROR) {
411 git_inflate_end(&st->z);
412 st->z_state = z_error;
413 return -1;
414 }
415 }
416 return total_read;
417 }
418
419 static close_method_decl(pack_non_delta)
420 {
421 close_deflated_stream(st);
422 return 0;
423 }
424
425 static struct stream_vtbl pack_non_delta_vtbl = {
426 close_istream_pack_non_delta,
427 read_istream_pack_non_delta,
428 };
429
430 static open_method_decl(pack_non_delta)
431 {
432 struct pack_window *window;
433 enum object_type in_pack_type;
434
435 st->u.in_pack.pack = oi->u.packed.pack;
436 st->u.in_pack.pos = oi->u.packed.offset;
437 window = NULL;
438
439 in_pack_type = unpack_object_header(st->u.in_pack.pack,
440 &window,
441 &st->u.in_pack.pos,
442 &st->size);
443 unuse_pack(&window);
444 switch (in_pack_type) {
445 default:
446 return -1; /* we do not do deltas for now */
447 case OBJ_COMMIT:
448 case OBJ_TREE:
449 case OBJ_BLOB:
450 case OBJ_TAG:
451 break;
452 }
453 st->z_state = z_unused;
454 st->vtbl = &pack_non_delta_vtbl;
455 return 0;
456 }
457
458
459 /*****************************************************************
460 *
461 * In-core stream
462 *
463 *****************************************************************/
464
465 static close_method_decl(incore)
466 {
467 free(st->u.incore.buf);
468 return 0;
469 }
470
471 static read_method_decl(incore)
472 {
473 size_t read_size = sz;
474 size_t remainder = st->size - st->u.incore.read_ptr;
475
476 if (remainder <= read_size)
477 read_size = remainder;
478 if (read_size) {
479 memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
480 st->u.incore.read_ptr += read_size;
481 }
482 return read_size;
483 }
484
485 static struct stream_vtbl incore_vtbl = {
486 close_istream_incore,
487 read_istream_incore,
488 };
489
490 static open_method_decl(incore)
491 {
492 st->u.incore.buf = read_object_file_extended(oid, type, &st->size, 0);
493 st->u.incore.read_ptr = 0;
494 st->vtbl = &incore_vtbl;
495
496 return st->u.incore.buf ? 0 : -1;
497 }
498
499
500 /****************************************************************
501 * Users of streaming interface
502 ****************************************************************/
503
504 int stream_blob_to_fd(int fd, const struct object_id *oid, struct stream_filter *filter,
505 int can_seek)
506 {
507 struct git_istream *st;
508 enum object_type type;
509 unsigned long sz;
510 ssize_t kept = 0;
511 int result = -1;
512
513 st = open_istream(oid, &type, &sz, filter);
514 if (!st) {
515 if (filter)
516 free_stream_filter(filter);
517 return result;
518 }
519 if (type != OBJ_BLOB)
520 goto close_and_exit;
521 for (;;) {
522 char buf[1024 * 16];
523 ssize_t wrote, holeto;
524 ssize_t readlen = read_istream(st, buf, sizeof(buf));
525
526 if (readlen < 0)
527 goto close_and_exit;
528 if (!readlen)
529 break;
530 if (can_seek && sizeof(buf) == readlen) {
531 for (holeto = 0; holeto < readlen; holeto++)
532 if (buf[holeto])
533 break;
534 if (readlen == holeto) {
535 kept += holeto;
536 continue;
537 }
538 }
539
540 if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
541 goto close_and_exit;
542 else
543 kept = 0;
544 wrote = write_in_full(fd, buf, readlen);
545
546 if (wrote < 0)
547 goto close_and_exit;
548 }
549 if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
550 xwrite(fd, "", 1) != 1))
551 goto close_and_exit;
552 result = 0;
553
554 close_and_exit:
555 close_istream(st);
556 return result;
557 }