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46bf043 @gitster streaming: a new API to read from the object store
authored
1 /*
2 * Copyright (c) 2011, Google Inc.
3 */
4 #include "cache.h"
5 #include "streaming.h"
6
7 enum input_source {
8 stream_error = -1,
9 incore = 0,
10 loose = 1,
11 pack_non_delta = 2
12 };
13
14 typedef int (*open_istream_fn)(struct git_istream *,
15 struct object_info *,
16 const unsigned char *,
17 enum object_type *);
18 typedef int (*close_istream_fn)(struct git_istream *);
19 typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);
20
21 struct stream_vtbl {
22 close_istream_fn close;
23 read_istream_fn read;
24 };
25
26 #define open_method_decl(name) \
27 int open_istream_ ##name \
28 (struct git_istream *st, struct object_info *oi, \
29 const unsigned char *sha1, \
30 enum object_type *type)
31
32 #define close_method_decl(name) \
33 int close_istream_ ##name \
34 (struct git_istream *st)
35
36 #define read_method_decl(name) \
37 ssize_t read_istream_ ##name \
38 (struct git_istream *st, char *buf, size_t sz)
39
40 /* forward declaration */
41 static open_method_decl(incore);
42 static open_method_decl(loose);
43 static open_method_decl(pack_non_delta);
b669109 @gitster Add streaming filter API
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44 static struct git_istream *attach_stream_filter(struct git_istream *st,
45 struct stream_filter *filter);
46
46bf043 @gitster streaming: a new API to read from the object store
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47
48 static open_istream_fn open_istream_tbl[] = {
49 open_istream_incore,
50 open_istream_loose,
51 open_istream_pack_non_delta,
52 };
53
b669109 @gitster Add streaming filter API
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54 #define FILTER_BUFFER (1024*16)
55
56 struct filtered_istream {
57 struct git_istream *upstream;
58 struct stream_filter *filter;
59 char ibuf[FILTER_BUFFER];
60 char obuf[FILTER_BUFFER];
61 int i_end, i_ptr;
62 int o_end, o_ptr;
4ae6670 @gitster stream filter: add "no more input" to the filters
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63 int input_finished;
b669109 @gitster Add streaming filter API
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64 };
65
46bf043 @gitster streaming: a new API to read from the object store
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66 struct git_istream {
67 const struct stream_vtbl *vtbl;
68 unsigned long size; /* inflated size of full object */
eb4f407 @gitster Merge branch 'jc/zlib-wrap'
authored
69 git_zstream z;
7ef2d9a @gitster streaming: read non-delta incrementally from a pack
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70 enum { z_unused, z_used, z_done, z_error } z_state;
46bf043 @gitster streaming: a new API to read from the object store
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71
72 union {
73 struct {
74 char *buf; /* from read_object() */
75 unsigned long read_ptr;
76 } incore;
77
78 struct {
93aa7bd @gitster streaming: read loose objects incrementally
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79 void *mapped;
80 unsigned long mapsize;
81 char hdr[32];
82 int hdr_avail;
83 int hdr_used;
46bf043 @gitster streaming: a new API to read from the object store
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84 } loose;
85
86 struct {
7ef2d9a @gitster streaming: read non-delta incrementally from a pack
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87 struct packed_git *pack;
88 off_t pos;
46bf043 @gitster streaming: a new API to read from the object store
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89 } in_pack;
b669109 @gitster Add streaming filter API
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90
91 struct filtered_istream filtered;
46bf043 @gitster streaming: a new API to read from the object store
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92 } u;
93 };
94
95 int close_istream(struct git_istream *st)
96 {
95dea6e @peff streaming: free git_istream upon closing
peff authored
97 int r = st->vtbl->close(st);
98 free(st);
99 return r;
46bf043 @gitster streaming: a new API to read from the object store
authored
100 }
101
6163cd8 streaming: void pointer instead of char pointer
René Scharfe authored
102 ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
46bf043 @gitster streaming: a new API to read from the object store
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103 {
104 return st->vtbl->read(st, buf, sz);
105 }
106
107 static enum input_source istream_source(const unsigned char *sha1,
108 enum object_type *type,
109 struct object_info *oi)
110 {
111 unsigned long size;
112 int status;
113
114 oi->sizep = &size;
115 status = sha1_object_info_extended(sha1, oi);
116 if (status < 0)
117 return stream_error;
118 *type = status;
119
120 switch (oi->whence) {
121 case OI_LOOSE:
122 return loose;
123 case OI_PACKED:
754980d @pclouds pack-objects, streaming: turn "xx >= big_file_threshold" to ".. > .."
pclouds authored
124 if (!oi->u.packed.is_delta && big_file_threshold < size)
46bf043 @gitster streaming: a new API to read from the object store
authored
125 return pack_non_delta;
126 /* fallthru */
127 default:
128 return incore;
129 }
130 }
131
132 struct git_istream *open_istream(const unsigned char *sha1,
133 enum object_type *type,
b669109 @gitster Add streaming filter API
authored
134 unsigned long *size,
135 struct stream_filter *filter)
46bf043 @gitster streaming: a new API to read from the object store
authored
136 {
137 struct git_istream *st;
138 struct object_info oi;
139 const unsigned char *real = lookup_replace_object(sha1);
140 enum input_source src = istream_source(real, type, &oi);
141
142 if (src < 0)
143 return NULL;
144
145 st = xmalloc(sizeof(*st));
146 if (open_istream_tbl[src](st, &oi, real, type)) {
147 if (open_istream_incore(st, &oi, real, type)) {
148 free(st);
149 return NULL;
150 }
151 }
b669109 @gitster Add streaming filter API
authored
152 if (st && filter) {
153 /* Add "&& !is_null_stream_filter(filter)" for performance */
154 struct git_istream *nst = attach_stream_filter(st, filter);
155 if (!nst)
156 close_istream(st);
157 st = nst;
158 }
159
46bf043 @gitster streaming: a new API to read from the object store
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160 *size = st->size;
161 return st;
162 }
163
7ef2d9a @gitster streaming: read non-delta incrementally from a pack
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164
165 /*****************************************************************
166 *
167 * Common helpers
168 *
169 *****************************************************************/
170
171 static void close_deflated_stream(struct git_istream *st)
172 {
173 if (st->z_state == z_used)
174 git_inflate_end(&st->z);
175 }
176
177
46bf043 @gitster streaming: a new API to read from the object store
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178 /*****************************************************************
179 *
b669109 @gitster Add streaming filter API
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180 * Filtered stream
181 *
182 *****************************************************************/
183
184 static close_method_decl(filtered)
185 {
186 free_stream_filter(st->u.filtered.filter);
187 return close_istream(st->u.filtered.upstream);
188 }
189
190 static read_method_decl(filtered)
191 {
192 struct filtered_istream *fs = &(st->u.filtered);
193 size_t filled = 0;
194
195 while (sz) {
196 /* do we already have filtered output? */
197 if (fs->o_ptr < fs->o_end) {
198 size_t to_move = fs->o_end - fs->o_ptr;
199 if (sz < to_move)
200 to_move = sz;
201 memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
202 fs->o_ptr += to_move;
203 sz -= to_move;
204 filled += to_move;
205 continue;
206 }
207 fs->o_end = fs->o_ptr = 0;
208
209 /* do we have anything to feed the filter with? */
210 if (fs->i_ptr < fs->i_end) {
211 size_t to_feed = fs->i_end - fs->i_ptr;
212 size_t to_receive = FILTER_BUFFER;
213 if (stream_filter(fs->filter,
214 fs->ibuf + fs->i_ptr, &to_feed,
215 fs->obuf, &to_receive))
216 return -1;
217 fs->i_ptr = fs->i_end - to_feed;
218 fs->o_end = FILTER_BUFFER - to_receive;
219 continue;
220 }
4ae6670 @gitster stream filter: add "no more input" to the filters
authored
221
222 /* tell the filter to drain upon no more input */
223 if (fs->input_finished) {
224 size_t to_receive = FILTER_BUFFER;
225 if (stream_filter(fs->filter,
226 NULL, NULL,
227 fs->obuf, &to_receive))
228 return -1;
229 fs->o_end = FILTER_BUFFER - to_receive;
230 if (!fs->o_end)
231 break;
232 continue;
233 }
b669109 @gitster Add streaming filter API
authored
234 fs->i_end = fs->i_ptr = 0;
235
236 /* refill the input from the upstream */
4ae6670 @gitster stream filter: add "no more input" to the filters
authored
237 if (!fs->input_finished) {
238 fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
239 if (fs->i_end < 0)
240 break;
241 if (fs->i_end)
242 continue;
243 }
244 fs->input_finished = 1;
b669109 @gitster Add streaming filter API
authored
245 }
246 return filled;
247 }
248
249 static struct stream_vtbl filtered_vtbl = {
250 close_istream_filtered,
251 read_istream_filtered,
252 };
253
254 static struct git_istream *attach_stream_filter(struct git_istream *st,
255 struct stream_filter *filter)
256 {
257 struct git_istream *ifs = xmalloc(sizeof(*ifs));
258 struct filtered_istream *fs = &(ifs->u.filtered);
259
260 ifs->vtbl = &filtered_vtbl;
261 fs->upstream = st;
262 fs->filter = filter;
263 fs->i_end = fs->i_ptr = 0;
264 fs->o_end = fs->o_ptr = 0;
4ae6670 @gitster stream filter: add "no more input" to the filters
authored
265 fs->input_finished = 0;
b669109 @gitster Add streaming filter API
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266 ifs->size = -1; /* unknown */
267 return ifs;
268 }
269
270 /*****************************************************************
271 *
46bf043 @gitster streaming: a new API to read from the object store
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272 * Loose object stream
273 *
274 *****************************************************************/
275
93aa7bd @gitster streaming: read loose objects incrementally
authored
276 static read_method_decl(loose)
277 {
278 size_t total_read = 0;
279
280 switch (st->z_state) {
281 case z_done:
282 return 0;
283 case z_error:
284 return -1;
285 default:
286 break;
287 }
288
289 if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
290 size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
291 if (sz < to_copy)
292 to_copy = sz;
293 memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
294 st->u.loose.hdr_used += to_copy;
295 total_read += to_copy;
296 }
297
298 while (total_read < sz) {
299 int status;
300
301 st->z.next_out = (unsigned char *)buf + total_read;
302 st->z.avail_out = sz - total_read;
303 status = git_inflate(&st->z, Z_FINISH);
304
305 total_read = st->z.next_out - (unsigned char *)buf;
306
307 if (status == Z_STREAM_END) {
308 git_inflate_end(&st->z);
309 st->z_state = z_done;
310 break;
311 }
312 if (status != Z_OK && status != Z_BUF_ERROR) {
313 git_inflate_end(&st->z);
314 st->z_state = z_error;
315 return -1;
316 }
317 }
318 return total_read;
319 }
320
321 static close_method_decl(loose)
322 {
323 close_deflated_stream(st);
324 munmap(st->u.loose.mapped, st->u.loose.mapsize);
325 return 0;
326 }
327
328 static struct stream_vtbl loose_vtbl = {
329 close_istream_loose,
330 read_istream_loose,
331 };
332
46bf043 @gitster streaming: a new API to read from the object store
authored
333 static open_method_decl(loose)
334 {
93aa7bd @gitster streaming: read loose objects incrementally
authored
335 st->u.loose.mapped = map_sha1_file(sha1, &st->u.loose.mapsize);
336 if (!st->u.loose.mapped)
337 return -1;
338 if (unpack_sha1_header(&st->z,
339 st->u.loose.mapped,
340 st->u.loose.mapsize,
341 st->u.loose.hdr,
342 sizeof(st->u.loose.hdr)) < 0) {
343 git_inflate_end(&st->z);
344 munmap(st->u.loose.mapped, st->u.loose.mapsize);
345 return -1;
346 }
347
348 parse_sha1_header(st->u.loose.hdr, &st->size);
349 st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
350 st->u.loose.hdr_avail = st->z.total_out;
351 st->z_state = z_used;
352
353 st->vtbl = &loose_vtbl;
354 return 0;
46bf043 @gitster streaming: a new API to read from the object store
authored
355 }
356
357
358 /*****************************************************************
359 *
360 * Non-delta packed object stream
361 *
362 *****************************************************************/
363
7ef2d9a @gitster streaming: read non-delta incrementally from a pack
authored
364 static read_method_decl(pack_non_delta)
365 {
366 size_t total_read = 0;
367
368 switch (st->z_state) {
369 case z_unused:
370 memset(&st->z, 0, sizeof(st->z));
371 git_inflate_init(&st->z);
372 st->z_state = z_used;
373 break;
374 case z_done:
375 return 0;
376 case z_error:
377 return -1;
378 case z_used:
379 break;
380 }
381
382 while (total_read < sz) {
383 int status;
384 struct pack_window *window = NULL;
385 unsigned char *mapped;
386
387 mapped = use_pack(st->u.in_pack.pack, &window,
388 st->u.in_pack.pos, &st->z.avail_in);
389
390 st->z.next_out = (unsigned char *)buf + total_read;
391 st->z.avail_out = sz - total_read;
392 st->z.next_in = mapped;
393 status = git_inflate(&st->z, Z_FINISH);
394
395 st->u.in_pack.pos += st->z.next_in - mapped;
396 total_read = st->z.next_out - (unsigned char *)buf;
397 unuse_pack(&window);
398
399 if (status == Z_STREAM_END) {
400 git_inflate_end(&st->z);
401 st->z_state = z_done;
402 break;
403 }
404 if (status != Z_OK && status != Z_BUF_ERROR) {
405 git_inflate_end(&st->z);
406 st->z_state = z_error;
407 return -1;
408 }
409 }
410 return total_read;
411 }
412
413 static close_method_decl(pack_non_delta)
414 {
415 close_deflated_stream(st);
416 return 0;
417 }
418
419 static struct stream_vtbl pack_non_delta_vtbl = {
420 close_istream_pack_non_delta,
421 read_istream_pack_non_delta,
422 };
423
46bf043 @gitster streaming: a new API to read from the object store
authored
424 static open_method_decl(pack_non_delta)
425 {
7ef2d9a @gitster streaming: read non-delta incrementally from a pack
authored
426 struct pack_window *window;
427 enum object_type in_pack_type;
428
429 st->u.in_pack.pack = oi->u.packed.pack;
430 st->u.in_pack.pos = oi->u.packed.offset;
431 window = NULL;
432
433 in_pack_type = unpack_object_header(st->u.in_pack.pack,
434 &window,
435 &st->u.in_pack.pos,
436 &st->size);
437 unuse_pack(&window);
438 switch (in_pack_type) {
439 default:
440 return -1; /* we do not do deltas for now */
441 case OBJ_COMMIT:
442 case OBJ_TREE:
443 case OBJ_BLOB:
444 case OBJ_TAG:
445 break;
446 }
447 st->z_state = z_unused;
448 st->vtbl = &pack_non_delta_vtbl;
449 return 0;
46bf043 @gitster streaming: a new API to read from the object store
authored
450 }
451
452
453 /*****************************************************************
454 *
455 * In-core stream
456 *
457 *****************************************************************/
458
459 static close_method_decl(incore)
460 {
461 free(st->u.incore.buf);
462 return 0;
463 }
464
465 static read_method_decl(incore)
466 {
467 size_t read_size = sz;
468 size_t remainder = st->size - st->u.incore.read_ptr;
469
470 if (remainder <= read_size)
471 read_size = remainder;
472 if (read_size) {
473 memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
474 st->u.incore.read_ptr += read_size;
475 }
476 return read_size;
477 }
478
479 static struct stream_vtbl incore_vtbl = {
480 close_istream_incore,
481 read_istream_incore,
482 };
483
484 static open_method_decl(incore)
485 {
486 st->u.incore.buf = read_sha1_file_extended(sha1, type, &st->size, 0);
487 st->u.incore.read_ptr = 0;
488 st->vtbl = &incore_vtbl;
489
490 return st->u.incore.buf ? 0 : -1;
491 }
47a02ff @gitster streaming: make streaming-write-entry to be more reusable
authored
492
493
494 /****************************************************************
495 * Users of streaming interface
496 ****************************************************************/
497
498 int stream_blob_to_fd(int fd, unsigned const char *sha1, struct stream_filter *filter,
499 int can_seek)
500 {
501 struct git_istream *st;
502 enum object_type type;
503 unsigned long sz;
504 ssize_t kept = 0;
505 int result = -1;
506
507 st = open_istream(sha1, &type, &sz, filter);
508 if (!st)
509 return result;
510 if (type != OBJ_BLOB)
511 goto close_and_exit;
512 for (;;) {
513 char buf[1024 * 16];
514 ssize_t wrote, holeto;
515 ssize_t readlen = read_istream(st, buf, sizeof(buf));
516
517 if (!readlen)
518 break;
519 if (can_seek && sizeof(buf) == readlen) {
520 for (holeto = 0; holeto < readlen; holeto++)
521 if (buf[holeto])
522 break;
523 if (readlen == holeto) {
524 kept += holeto;
525 continue;
526 }
527 }
528
529 if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
530 goto close_and_exit;
531 else
532 kept = 0;
533 wrote = write_in_full(fd, buf, readlen);
534
535 if (wrote != readlen)
536 goto close_and_exit;
537 }
538 if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
539 write(fd, "", 1) != 1))
540 goto close_and_exit;
541 result = 0;
542
543 close_and_exit:
544 close_istream(st);
545 return result;
546 }
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