Merge branch 'mh/notes-duplicate-entries'
[git/git.git] / streaming.c
CommitLineData
46bf0438
JH
1/*
2 * Copyright (c) 2011, Google Inc.
3 */
4#include "cache.h"
5#include "streaming.h"
e35454fa
SB
6#include "repository.h"
7#include "object-store.h"
47f351e9 8#include "replace-object.h"
84f80ad5 9#include "packfile.h"
46bf0438
JH
10
11enum input_source {
12 stream_error = -1,
13 incore = 0,
14 loose = 1,
15 pack_non_delta = 2
16};
17
18typedef int (*open_istream_fn)(struct git_istream *,
19 struct object_info *,
575042a0 20 const struct object_id *,
46bf0438
JH
21 enum object_type *);
22typedef int (*close_istream_fn)(struct git_istream *);
23typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);
24
25struct stream_vtbl {
26 close_istream_fn close;
27 read_istream_fn read;
28};
29
30#define open_method_decl(name) \
31 int open_istream_ ##name \
32 (struct git_istream *st, struct object_info *oi, \
575042a0 33 const struct object_id *oid, \
46bf0438
JH
34 enum object_type *type)
35
36#define close_method_decl(name) \
37 int close_istream_ ##name \
38 (struct git_istream *st)
39
40#define read_method_decl(name) \
41 ssize_t read_istream_ ##name \
42 (struct git_istream *st, char *buf, size_t sz)
43
44/* forward declaration */
45static open_method_decl(incore);
46static open_method_decl(loose);
47static open_method_decl(pack_non_delta);
b6691092
JH
48static struct git_istream *attach_stream_filter(struct git_istream *st,
49 struct stream_filter *filter);
50
46bf0438
JH
51
52static open_istream_fn open_istream_tbl[] = {
53 open_istream_incore,
54 open_istream_loose,
55 open_istream_pack_non_delta,
56};
57
b6691092
JH
58#define FILTER_BUFFER (1024*16)
59
60struct 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;
4ae66704 67 int input_finished;
b6691092
JH
68};
69
46bf0438
JH
70struct git_istream {
71 const struct stream_vtbl *vtbl;
72 unsigned long size; /* inflated size of full object */
eb4f4076 73 git_zstream z;
7ef2d9a2 74 enum { z_unused, z_used, z_done, z_error } z_state;
46bf0438
JH
75
76 union {
77 struct {
78 char *buf; /* from read_object() */
79 unsigned long read_ptr;
80 } incore;
81
82 struct {
93aa7bd5
JH
83 void *mapped;
84 unsigned long mapsize;
85 char hdr[32];
86 int hdr_avail;
87 int hdr_used;
46bf0438
JH
88 } loose;
89
90 struct {
7ef2d9a2
JH
91 struct packed_git *pack;
92 off_t pos;
46bf0438 93 } in_pack;
b6691092
JH
94
95 struct filtered_istream filtered;
46bf0438
JH
96 } u;
97};
98
99int close_istream(struct git_istream *st)
100{
95dea6eb
JK
101 int r = st->vtbl->close(st);
102 free(st);
103 return r;
46bf0438
JH
104}
105
6163cd8a 106ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
46bf0438
JH
107{
108 return st->vtbl->read(st, buf, sz);
109}
110
b383a13c 111static enum input_source istream_source(const struct object_id *oid,
46bf0438
JH
112 enum object_type *type,
113 struct object_info *oi)
114{
115 unsigned long size;
116 int status;
117
5b086407 118 oi->typep = type;
46bf0438 119 oi->sizep = &size;
7ecd8690 120 status = oid_object_info_extended(the_repository, oid, oi, 0);
46bf0438
JH
121 if (status < 0)
122 return stream_error;
46bf0438
JH
123
124 switch (oi->whence) {
125 case OI_LOOSE:
126 return loose;
127 case OI_PACKED:
754980d0 128 if (!oi->u.packed.is_delta && big_file_threshold < size)
46bf0438
JH
129 return pack_non_delta;
130 /* fallthru */
131 default:
132 return incore;
133 }
134}
135
ef7b5195 136struct git_istream *open_istream(const struct object_id *oid,
46bf0438 137 enum object_type *type,
b6691092
JH
138 unsigned long *size,
139 struct stream_filter *filter)
46bf0438
JH
140{
141 struct git_istream *st;
27b5c1a0 142 struct object_info oi = OBJECT_INFO_INIT;
1f2e7cea 143 const struct object_id *real = lookup_replace_object(the_repository, oid);
46bf0438
JH
144 enum input_source src = istream_source(real, type, &oi);
145
146 if (src < 0)
147 return NULL;
148
149 st = xmalloc(sizeof(*st));
b383a13c 150 if (open_istream_tbl[src](st, &oi, real, type)) {
151 if (open_istream_incore(st, &oi, real, type)) {
46bf0438
JH
152 free(st);
153 return NULL;
154 }
155 }
6a907786 156 if (filter) {
b6691092
JH
157 /* Add "&& !is_null_stream_filter(filter)" for performance */
158 struct git_istream *nst = attach_stream_filter(st, filter);
78368f2c 159 if (!nst) {
b6691092 160 close_istream(st);
78368f2c
JH
161 return NULL;
162 }
b6691092
JH
163 st = nst;
164 }
165
46bf0438
JH
166 *size = st->size;
167 return st;
168}
169
7ef2d9a2
JH
170
171/*****************************************************************
172 *
173 * Common helpers
174 *
175 *****************************************************************/
176
177static void close_deflated_stream(struct git_istream *st)
178{
179 if (st->z_state == z_used)
180 git_inflate_end(&st->z);
181}
182
183
b6691092
JH
184/*****************************************************************
185 *
186 * Filtered stream
187 *
188 *****************************************************************/
189
190static close_method_decl(filtered)
191{
192 free_stream_filter(st->u.filtered.filter);
193 return close_istream(st->u.filtered.upstream);
194}
195
196static read_method_decl(filtered)
197{
198 struct filtered_istream *fs = &(st->u.filtered);
199 size_t filled = 0;
200
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;
212 }
213 fs->o_end = fs->o_ptr = 0;
214
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;
226 }
4ae66704
JH
227
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;
239 }
b6691092
JH
240 fs->i_end = fs->i_ptr = 0;
241
242 /* refill the input from the upstream */
4ae66704
JH
243 if (!fs->input_finished) {
244 fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
245 if (fs->i_end < 0)
42e7e2a5 246 return -1;
4ae66704
JH
247 if (fs->i_end)
248 continue;
249 }
250 fs->input_finished = 1;
b6691092
JH
251 }
252 return filled;
253}
254
255static struct stream_vtbl filtered_vtbl = {
256 close_istream_filtered,
257 read_istream_filtered,
258};
259
260static struct git_istream *attach_stream_filter(struct git_istream *st,
261 struct stream_filter *filter)
262{
263 struct git_istream *ifs = xmalloc(sizeof(*ifs));
264 struct filtered_istream *fs = &(ifs->u.filtered);
265
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;
4ae66704 271 fs->input_finished = 0;
b6691092
JH
272 ifs->size = -1; /* unknown */
273 return ifs;
274}
275
46bf0438
JH
276/*****************************************************************
277 *
278 * Loose object stream
279 *
280 *****************************************************************/
281
93aa7bd5
JH
282static read_method_decl(loose)
283{
284 size_t total_read = 0;
285
286 switch (st->z_state) {
287 case z_done:
288 return 0;
289 case z_error:
290 return -1;
291 default:
292 break;
293 }
294
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;
302 }
303
304 while (total_read < sz) {
305 int status;
306
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);
310
311 total_read = st->z.next_out - (unsigned char *)buf;
312
313 if (status == Z_STREAM_END) {
314 git_inflate_end(&st->z);
315 st->z_state = z_done;
316 break;
317 }
692f0bc7 318 if (status != Z_OK && (status != Z_BUF_ERROR || total_read < sz)) {
93aa7bd5
JH
319 git_inflate_end(&st->z);
320 st->z_state = z_error;
321 return -1;
322 }
323 }
324 return total_read;
325}
326
327static close_method_decl(loose)
328{
329 close_deflated_stream(st);
330 munmap(st->u.loose.mapped, st->u.loose.mapsize);
331 return 0;
332}
333
334static struct stream_vtbl loose_vtbl = {
335 close_istream_loose,
336 read_istream_loose,
337};
338
46bf0438
JH
339static open_method_decl(loose)
340{
514c5fdd
JK
341 st->u.loose.mapped = map_loose_object(the_repository,
342 oid, &st->u.loose.mapsize);
93aa7bd5
JH
343 if (!st->u.loose.mapped)
344 return -1;
00a7760e
JK
345 if ((unpack_loose_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_loose_header(st->u.loose.hdr, &st->size) < 0)) {
93aa7bd5
JH
351 git_inflate_end(&st->z);
352 munmap(st->u.loose.mapped, st->u.loose.mapsize);
353 return -1;
354 }
355
93aa7bd5
JH
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;
359
360 st->vtbl = &loose_vtbl;
361 return 0;
46bf0438
JH
362}
363
364
365/*****************************************************************
366 *
367 * Non-delta packed object stream
368 *
369 *****************************************************************/
370
7ef2d9a2
JH
371static read_method_decl(pack_non_delta)
372{
373 size_t total_read = 0;
374
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;
387 }
388
389 while (total_read < sz) {
390 int status;
391 struct pack_window *window = NULL;
392 unsigned char *mapped;
393
394 mapped = use_pack(st->u.in_pack.pack, &window,
395 st->u.in_pack.pos, &st->z.avail_in);
396
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);
401
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);
405
406 if (status == Z_STREAM_END) {
407 git_inflate_end(&st->z);
408 st->z_state = z_done;
409 break;
410 }
0afbe3e8
JK
411
412 /*
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().
419 */
7ef2d9a2
JH
420 if (status != Z_OK && status != Z_BUF_ERROR) {
421 git_inflate_end(&st->z);
422 st->z_state = z_error;
423 return -1;
424 }
425 }
426 return total_read;
427}
428
429static close_method_decl(pack_non_delta)
430{
431 close_deflated_stream(st);
432 return 0;
433}
434
435static struct stream_vtbl pack_non_delta_vtbl = {
436 close_istream_pack_non_delta,
437 read_istream_pack_non_delta,
438};
439
46bf0438
JH
440static open_method_decl(pack_non_delta)
441{
7ef2d9a2
JH
442 struct pack_window *window;
443 enum object_type in_pack_type;
444
445 st->u.in_pack.pack = oi->u.packed.pack;
446 st->u.in_pack.pos = oi->u.packed.offset;
447 window = NULL;
448
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;
462 }
463 st->z_state = z_unused;
464 st->vtbl = &pack_non_delta_vtbl;
465 return 0;
46bf0438
JH
466}
467
468
469/*****************************************************************
470 *
471 * In-core stream
472 *
473 *****************************************************************/
474
475static close_method_decl(incore)
476{
477 free(st->u.incore.buf);
478 return 0;
479}
480
481static read_method_decl(incore)
482{
483 size_t read_size = sz;
484 size_t remainder = st->size - st->u.incore.read_ptr;
485
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;
491 }
492 return read_size;
493}
494
495static struct stream_vtbl incore_vtbl = {
496 close_istream_incore,
497 read_istream_incore,
498};
499
500static open_method_decl(incore)
501{
a3b72c89 502 st->u.incore.buf = read_object_file_extended(the_repository, oid, type, &st->size, 0);
46bf0438
JH
503 st->u.incore.read_ptr = 0;
504 st->vtbl = &incore_vtbl;
505
506 return st->u.incore.buf ? 0 : -1;
507}
47a02ff2
JH
508
509
510/****************************************************************
511 * Users of streaming interface
512 ****************************************************************/
513
7eda0e4f 514int stream_blob_to_fd(int fd, const struct object_id *oid, struct stream_filter *filter,
47a02ff2
JH
515 int can_seek)
516{
517 struct git_istream *st;
518 enum object_type type;
519 unsigned long sz;
520 ssize_t kept = 0;
521 int result = -1;
522
ef7b5195 523 st = open_istream(oid, &type, &sz, filter);
9ce4ad3e
JK
524 if (!st) {
525 if (filter)
526 free_stream_filter(filter);
47a02ff2 527 return result;
9ce4ad3e 528 }
47a02ff2
JH
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));
535
45d4bdae
JK
536 if (readlen < 0)
537 goto close_and_exit;
47a02ff2
JH
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;
547 }
548 }
549
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);
555
564bde9a 556 if (wrote < 0)
47a02ff2
JH
557 goto close_and_exit;
558 }
559 if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
7edc02f4 560 xwrite(fd, "", 1) != 1))
47a02ff2
JH
561 goto close_and_exit;
562 result = 0;
563
564 close_and_exit:
565 close_istream(st);
566 return result;
567}