Merge branch 'bb/git-gui-ssh-key-files'
[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 }