Sync with maint
[git.git] / streaming.c
blob2ff036a0fa6c8e7b013d061d16baf33045305950
1 /*
2 * Copyright (c) 2011, Google Inc.
3 */
4 #include "cache.h"
5 #include "streaming.h"
7 enum input_source {
8 stream_error = -1,
9 incore = 0,
10 loose = 1,
11 pack_non_delta = 2
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);
21 struct stream_vtbl {
22 close_istream_fn close;
23 read_istream_fn read;
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)
32 #define close_method_decl(name) \
33 int close_istream_ ##name \
34 (struct git_istream *st)
36 #define read_method_decl(name) \
37 ssize_t read_istream_ ##name \
38 (struct git_istream *st, char *buf, size_t sz)
40 /* forward declaration */
41 static open_method_decl(incore);
42 static open_method_decl(loose);
43 static open_method_decl(pack_non_delta);
44 static struct git_istream *attach_stream_filter(struct git_istream *st,
45 struct stream_filter *filter);
48 static open_istream_fn open_istream_tbl[] = {
49 open_istream_incore,
50 open_istream_loose,
51 open_istream_pack_non_delta,
54 #define FILTER_BUFFER (1024*16)
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;
63 int input_finished;
66 struct git_istream {
67 const struct stream_vtbl *vtbl;
68 unsigned long size; /* inflated size of full object */
69 git_zstream z;
70 enum { z_unused, z_used, z_done, z_error } z_state;
72 union {
73 struct {
74 char *buf; /* from read_object() */
75 unsigned long read_ptr;
76 } incore;
78 struct {
79 void *mapped;
80 unsigned long mapsize;
81 char hdr[32];
82 int hdr_avail;
83 int hdr_used;
84 } loose;
86 struct {
87 struct packed_git *pack;
88 off_t pos;
89 } in_pack;
91 struct filtered_istream filtered;
92 } u;
95 int close_istream(struct git_istream *st)
97 int r = st->vtbl->close(st);
98 free(st);
99 return r;
102 ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
104 return st->vtbl->read(st, buf, sz);
107 static enum input_source istream_source(const unsigned char *sha1,
108 enum object_type *type,
109 struct object_info *oi)
111 unsigned long size;
112 int status;
114 oi->typep = type;
115 oi->sizep = &size;
116 status = sha1_object_info_extended(sha1, oi, 0);
117 if (status < 0)
118 return stream_error;
120 switch (oi->whence) {
121 case OI_LOOSE:
122 return loose;
123 case OI_PACKED:
124 if (!oi->u.packed.is_delta && big_file_threshold < size)
125 return pack_non_delta;
126 /* fallthru */
127 default:
128 return incore;
132 struct git_istream *open_istream(const unsigned char *sha1,
133 enum object_type *type,
134 unsigned long *size,
135 struct stream_filter *filter)
137 struct git_istream *st;
138 struct object_info oi = {NULL};
139 const unsigned char *real = lookup_replace_object(sha1);
140 enum input_source src = istream_source(real, type, &oi);
142 if (src < 0)
143 return NULL;
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;
152 if (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 return NULL;
159 st = nst;
162 *size = st->size;
163 return st;
167 /*****************************************************************
169 * Common helpers
171 *****************************************************************/
173 static void close_deflated_stream(struct git_istream *st)
175 if (st->z_state == z_used)
176 git_inflate_end(&st->z);
180 /*****************************************************************
182 * Filtered stream
184 *****************************************************************/
186 static close_method_decl(filtered)
188 free_stream_filter(st->u.filtered.filter);
189 return close_istream(st->u.filtered.upstream);
192 static read_method_decl(filtered)
194 struct filtered_istream *fs = &(st->u.filtered);
195 size_t filled = 0;
197 while (sz) {
198 /* do we already have filtered output? */
199 if (fs->o_ptr < fs->o_end) {
200 size_t to_move = fs->o_end - fs->o_ptr;
201 if (sz < to_move)
202 to_move = sz;
203 memcpy(buf + filled, fs->obuf + fs->o_ptr, to_move);
204 fs->o_ptr += to_move;
205 sz -= to_move;
206 filled += to_move;
207 continue;
209 fs->o_end = fs->o_ptr = 0;
211 /* do we have anything to feed the filter with? */
212 if (fs->i_ptr < fs->i_end) {
213 size_t to_feed = fs->i_end - fs->i_ptr;
214 size_t to_receive = FILTER_BUFFER;
215 if (stream_filter(fs->filter,
216 fs->ibuf + fs->i_ptr, &to_feed,
217 fs->obuf, &to_receive))
218 return -1;
219 fs->i_ptr = fs->i_end - to_feed;
220 fs->o_end = FILTER_BUFFER - to_receive;
221 continue;
224 /* tell the filter to drain upon no more input */
225 if (fs->input_finished) {
226 size_t to_receive = FILTER_BUFFER;
227 if (stream_filter(fs->filter,
228 NULL, NULL,
229 fs->obuf, &to_receive))
230 return -1;
231 fs->o_end = FILTER_BUFFER - to_receive;
232 if (!fs->o_end)
233 break;
234 continue;
236 fs->i_end = fs->i_ptr = 0;
238 /* refill the input from the upstream */
239 if (!fs->input_finished) {
240 fs->i_end = read_istream(fs->upstream, fs->ibuf, FILTER_BUFFER);
241 if (fs->i_end < 0)
242 return -1;
243 if (fs->i_end)
244 continue;
246 fs->input_finished = 1;
248 return filled;
251 static struct stream_vtbl filtered_vtbl = {
252 close_istream_filtered,
253 read_istream_filtered,
256 static struct git_istream *attach_stream_filter(struct git_istream *st,
257 struct stream_filter *filter)
259 struct git_istream *ifs = xmalloc(sizeof(*ifs));
260 struct filtered_istream *fs = &(ifs->u.filtered);
262 ifs->vtbl = &filtered_vtbl;
263 fs->upstream = st;
264 fs->filter = filter;
265 fs->i_end = fs->i_ptr = 0;
266 fs->o_end = fs->o_ptr = 0;
267 fs->input_finished = 0;
268 ifs->size = -1; /* unknown */
269 return ifs;
272 /*****************************************************************
274 * Loose object stream
276 *****************************************************************/
278 static read_method_decl(loose)
280 size_t total_read = 0;
282 switch (st->z_state) {
283 case z_done:
284 return 0;
285 case z_error:
286 return -1;
287 default:
288 break;
291 if (st->u.loose.hdr_used < st->u.loose.hdr_avail) {
292 size_t to_copy = st->u.loose.hdr_avail - st->u.loose.hdr_used;
293 if (sz < to_copy)
294 to_copy = sz;
295 memcpy(buf, st->u.loose.hdr + st->u.loose.hdr_used, to_copy);
296 st->u.loose.hdr_used += to_copy;
297 total_read += to_copy;
300 while (total_read < sz) {
301 int status;
303 st->z.next_out = (unsigned char *)buf + total_read;
304 st->z.avail_out = sz - total_read;
305 status = git_inflate(&st->z, Z_FINISH);
307 total_read = st->z.next_out - (unsigned char *)buf;
309 if (status == Z_STREAM_END) {
310 git_inflate_end(&st->z);
311 st->z_state = z_done;
312 break;
314 if (status != Z_OK && (status != Z_BUF_ERROR || total_read < sz)) {
315 git_inflate_end(&st->z);
316 st->z_state = z_error;
317 return -1;
320 return total_read;
323 static close_method_decl(loose)
325 close_deflated_stream(st);
326 munmap(st->u.loose.mapped, st->u.loose.mapsize);
327 return 0;
330 static struct stream_vtbl loose_vtbl = {
331 close_istream_loose,
332 read_istream_loose,
335 static open_method_decl(loose)
337 st->u.loose.mapped = map_sha1_file(sha1, &st->u.loose.mapsize);
338 if (!st->u.loose.mapped)
339 return -1;
340 if (unpack_sha1_header(&st->z,
341 st->u.loose.mapped,
342 st->u.loose.mapsize,
343 st->u.loose.hdr,
344 sizeof(st->u.loose.hdr)) < 0) {
345 git_inflate_end(&st->z);
346 munmap(st->u.loose.mapped, st->u.loose.mapsize);
347 return -1;
350 parse_sha1_header(st->u.loose.hdr, &st->size);
351 st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
352 st->u.loose.hdr_avail = st->z.total_out;
353 st->z_state = z_used;
355 st->vtbl = &loose_vtbl;
356 return 0;
360 /*****************************************************************
362 * Non-delta packed object stream
364 *****************************************************************/
366 static read_method_decl(pack_non_delta)
368 size_t total_read = 0;
370 switch (st->z_state) {
371 case z_unused:
372 memset(&st->z, 0, sizeof(st->z));
373 git_inflate_init(&st->z);
374 st->z_state = z_used;
375 break;
376 case z_done:
377 return 0;
378 case z_error:
379 return -1;
380 case z_used:
381 break;
384 while (total_read < sz) {
385 int status;
386 struct pack_window *window = NULL;
387 unsigned char *mapped;
389 mapped = use_pack(st->u.in_pack.pack, &window,
390 st->u.in_pack.pos, &st->z.avail_in);
392 st->z.next_out = (unsigned char *)buf + total_read;
393 st->z.avail_out = sz - total_read;
394 st->z.next_in = mapped;
395 status = git_inflate(&st->z, Z_FINISH);
397 st->u.in_pack.pos += st->z.next_in - mapped;
398 total_read = st->z.next_out - (unsigned char *)buf;
399 unuse_pack(&window);
401 if (status == Z_STREAM_END) {
402 git_inflate_end(&st->z);
403 st->z_state = z_done;
404 break;
406 if (status != Z_OK && status != Z_BUF_ERROR) {
407 git_inflate_end(&st->z);
408 st->z_state = z_error;
409 return -1;
412 return total_read;
415 static close_method_decl(pack_non_delta)
417 close_deflated_stream(st);
418 return 0;
421 static struct stream_vtbl pack_non_delta_vtbl = {
422 close_istream_pack_non_delta,
423 read_istream_pack_non_delta,
426 static open_method_decl(pack_non_delta)
428 struct pack_window *window;
429 enum object_type in_pack_type;
431 st->u.in_pack.pack = oi->u.packed.pack;
432 st->u.in_pack.pos = oi->u.packed.offset;
433 window = NULL;
435 in_pack_type = unpack_object_header(st->u.in_pack.pack,
436 &window,
437 &st->u.in_pack.pos,
438 &st->size);
439 unuse_pack(&window);
440 switch (in_pack_type) {
441 default:
442 return -1; /* we do not do deltas for now */
443 case OBJ_COMMIT:
444 case OBJ_TREE:
445 case OBJ_BLOB:
446 case OBJ_TAG:
447 break;
449 st->z_state = z_unused;
450 st->vtbl = &pack_non_delta_vtbl;
451 return 0;
455 /*****************************************************************
457 * In-core stream
459 *****************************************************************/
461 static close_method_decl(incore)
463 free(st->u.incore.buf);
464 return 0;
467 static read_method_decl(incore)
469 size_t read_size = sz;
470 size_t remainder = st->size - st->u.incore.read_ptr;
472 if (remainder <= read_size)
473 read_size = remainder;
474 if (read_size) {
475 memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
476 st->u.incore.read_ptr += read_size;
478 return read_size;
481 static struct stream_vtbl incore_vtbl = {
482 close_istream_incore,
483 read_istream_incore,
486 static open_method_decl(incore)
488 st->u.incore.buf = read_sha1_file_extended(sha1, type, &st->size, 0);
489 st->u.incore.read_ptr = 0;
490 st->vtbl = &incore_vtbl;
492 return st->u.incore.buf ? 0 : -1;
496 /****************************************************************
497 * Users of streaming interface
498 ****************************************************************/
500 int stream_blob_to_fd(int fd, unsigned const char *sha1, struct stream_filter *filter,
501 int can_seek)
503 struct git_istream *st;
504 enum object_type type;
505 unsigned long sz;
506 ssize_t kept = 0;
507 int result = -1;
509 st = open_istream(sha1, &type, &sz, filter);
510 if (!st)
511 return result;
512 if (type != OBJ_BLOB)
513 goto close_and_exit;
514 for (;;) {
515 char buf[1024 * 16];
516 ssize_t wrote, holeto;
517 ssize_t readlen = read_istream(st, buf, sizeof(buf));
519 if (readlen < 0)
520 goto close_and_exit;
521 if (!readlen)
522 break;
523 if (can_seek && sizeof(buf) == readlen) {
524 for (holeto = 0; holeto < readlen; holeto++)
525 if (buf[holeto])
526 break;
527 if (readlen == holeto) {
528 kept += holeto;
529 continue;
533 if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
534 goto close_and_exit;
535 else
536 kept = 0;
537 wrote = write_in_full(fd, buf, readlen);
539 if (wrote != readlen)
540 goto close_and_exit;
542 if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
543 xwrite(fd, "", 1) != 1))
544 goto close_and_exit;
545 result = 0;
547 close_and_exit:
548 close_istream(st);
549 return result;