Thread-safe xmalloc and xrealloc needs a recursive mutex
[git/dscho.git] / builtin-unpack-objects.c
blob685566e0b5e458c510fdf989744d63dda29e28f0
1 #include "builtin.h"
2 #include "cache.h"
3 #include "object.h"
4 #include "delta.h"
5 #include "pack.h"
6 #include "blob.h"
7 #include "commit.h"
8 #include "tag.h"
9 #include "tree.h"
10 #include "tree-walk.h"
11 #include "progress.h"
12 #include "decorate.h"
13 #include "fsck.h"
15 static int dry_run, quiet, recover, has_errors, strict;
16 static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict] < pack-file";
18 /* We always read in 4kB chunks. */
19 static unsigned char buffer[4096];
20 static unsigned int offset, len;
21 static off_t consumed_bytes;
22 static git_SHA_CTX ctx;
25  * When running under --strict mode, objects whose reachability are
26  * suspect are kept in core without getting written in the object
27  * store.
28  */
29 struct obj_buffer {
30         char *buffer;
31         unsigned long size;
34 static struct decoration obj_decorate;
36 static struct obj_buffer *lookup_object_buffer(struct object *base)
38         return lookup_decoration(&obj_decorate, base);
41 static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
43         struct obj_buffer *obj;
44         obj = xcalloc(1, sizeof(struct obj_buffer));
45         obj->buffer = buffer;
46         obj->size = size;
47         if (add_decoration(&obj_decorate, object, obj))
48                 die("object %s tried to add buffer twice!", sha1_to_hex(object->sha1));
52  * Make sure at least "min" bytes are available in the buffer, and
53  * return the pointer to the buffer.
54  */
55 static void *fill(int min)
57         if (min <= len)
58                 return buffer + offset;
59         if (min > sizeof(buffer))
60                 die("cannot fill %d bytes", min);
61         if (offset) {
62                 git_SHA1_Update(&ctx, buffer, offset);
63                 memmove(buffer, buffer + offset, len);
64                 offset = 0;
65         }
66         do {
67                 ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
68                 if (ret <= 0) {
69                         if (!ret)
70                                 die("early EOF");
71                         die_errno("read error on input");
72                 }
73                 len += ret;
74         } while (len < min);
75         return buffer;
78 static void use(int bytes)
80         if (bytes > len)
81                 die("used more bytes than were available");
82         len -= bytes;
83         offset += bytes;
85         /* make sure off_t is sufficiently large not to wrap */
86         if (consumed_bytes > consumed_bytes + bytes)
87                 die("pack too large for current definition of off_t");
88         consumed_bytes += bytes;
91 static void *get_data(unsigned long size)
93         z_stream stream;
94         void *buf = xmalloc(size);
96         memset(&stream, 0, sizeof(stream));
98         stream.next_out = buf;
99         stream.avail_out = size;
100         stream.next_in = fill(1);
101         stream.avail_in = len;
102         git_inflate_init(&stream);
104         for (;;) {
105                 int ret = git_inflate(&stream, 0);
106                 use(len - stream.avail_in);
107                 if (stream.total_out == size && ret == Z_STREAM_END)
108                         break;
109                 if (ret != Z_OK) {
110                         error("inflate returned %d\n", ret);
111                         free(buf);
112                         buf = NULL;
113                         if (!recover)
114                                 exit(1);
115                         has_errors = 1;
116                         break;
117                 }
118                 stream.next_in = fill(1);
119                 stream.avail_in = len;
120         }
121         git_inflate_end(&stream);
122         return buf;
125 struct delta_info {
126         unsigned char base_sha1[20];
127         unsigned nr;
128         off_t base_offset;
129         unsigned long size;
130         void *delta;
131         struct delta_info *next;
134 static struct delta_info *delta_list;
136 static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
137                               off_t base_offset,
138                               void *delta, unsigned long size)
140         struct delta_info *info = xmalloc(sizeof(*info));
142         hashcpy(info->base_sha1, base_sha1);
143         info->base_offset = base_offset;
144         info->size = size;
145         info->delta = delta;
146         info->nr = nr;
147         info->next = delta_list;
148         delta_list = info;
151 struct obj_info {
152         off_t offset;
153         unsigned char sha1[20];
154         struct object *obj;
157 #define FLAG_OPEN (1u<<20)
158 #define FLAG_WRITTEN (1u<<21)
160 static struct obj_info *obj_list;
161 static unsigned nr_objects;
164  * Called only from check_object() after it verified this object
165  * is Ok.
166  */
167 static void write_cached_object(struct object *obj)
169         unsigned char sha1[20];
170         struct obj_buffer *obj_buf = lookup_object_buffer(obj);
171         if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), sha1) < 0)
172                 die("failed to write object %s", sha1_to_hex(obj->sha1));
173         obj->flags |= FLAG_WRITTEN;
177  * At the very end of the processing, write_rest() scans the objects
178  * that have reachability requirements and calls this function.
179  * Verify its reachability and validity recursively and write it out.
180  */
181 static int check_object(struct object *obj, int type, void *data)
183         if (!obj)
184                 return 1;
186         if (obj->flags & FLAG_WRITTEN)
187                 return 0;
189         if (type != OBJ_ANY && obj->type != type)
190                 die("object type mismatch");
192         if (!(obj->flags & FLAG_OPEN)) {
193                 unsigned long size;
194                 int type = sha1_object_info(obj->sha1, &size);
195                 if (type != obj->type || type <= 0)
196                         die("object of unexpected type");
197                 obj->flags |= FLAG_WRITTEN;
198                 return 0;
199         }
201         if (fsck_object(obj, 1, fsck_error_function))
202                 die("Error in object");
203         if (fsck_walk(obj, check_object, NULL))
204                 die("Error on reachable objects of %s", sha1_to_hex(obj->sha1));
205         write_cached_object(obj);
206         return 0;
209 static void write_rest(void)
211         unsigned i;
212         for (i = 0; i < nr_objects; i++) {
213                 if (obj_list[i].obj)
214                         check_object(obj_list[i].obj, OBJ_ANY, NULL);
215         }
218 static void added_object(unsigned nr, enum object_type type,
219                          void *data, unsigned long size);
222  * Write out nr-th object from the list, now we know the contents
223  * of it.  Under --strict, this buffers structured objects in-core,
224  * to be checked at the end.
225  */
226 static void write_object(unsigned nr, enum object_type type,
227                          void *buf, unsigned long size)
229         if (!strict) {
230                 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
231                         die("failed to write object");
232                 added_object(nr, type, buf, size);
233                 free(buf);
234                 obj_list[nr].obj = NULL;
235         } else if (type == OBJ_BLOB) {
236                 struct blob *blob;
237                 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
238                         die("failed to write object");
239                 added_object(nr, type, buf, size);
240                 free(buf);
242                 blob = lookup_blob(obj_list[nr].sha1);
243                 if (blob)
244                         blob->object.flags |= FLAG_WRITTEN;
245                 else
246                         die("invalid blob object");
247                 obj_list[nr].obj = NULL;
248         } else {
249                 struct object *obj;
250                 int eaten;
251                 hash_sha1_file(buf, size, typename(type), obj_list[nr].sha1);
252                 added_object(nr, type, buf, size);
253                 obj = parse_object_buffer(obj_list[nr].sha1, type, size, buf, &eaten);
254                 if (!obj)
255                         die("invalid %s", typename(type));
256                 add_object_buffer(obj, buf, size);
257                 obj->flags |= FLAG_OPEN;
258                 obj_list[nr].obj = obj;
259         }
262 static void resolve_delta(unsigned nr, enum object_type type,
263                           void *base, unsigned long base_size,
264                           void *delta, unsigned long delta_size)
266         void *result;
267         unsigned long result_size;
269         result = patch_delta(base, base_size,
270                              delta, delta_size,
271                              &result_size);
272         if (!result)
273                 die("failed to apply delta");
274         free(delta);
275         write_object(nr, type, result, result_size);
279  * We now know the contents of an object (which is nr-th in the pack);
280  * resolve all the deltified objects that are based on it.
281  */
282 static void added_object(unsigned nr, enum object_type type,
283                          void *data, unsigned long size)
285         struct delta_info **p = &delta_list;
286         struct delta_info *info;
288         while ((info = *p) != NULL) {
289                 if (!hashcmp(info->base_sha1, obj_list[nr].sha1) ||
290                     info->base_offset == obj_list[nr].offset) {
291                         *p = info->next;
292                         p = &delta_list;
293                         resolve_delta(info->nr, type, data, size,
294                                       info->delta, info->size);
295                         free(info);
296                         continue;
297                 }
298                 p = &info->next;
299         }
302 static void unpack_non_delta_entry(enum object_type type, unsigned long size,
303                                    unsigned nr)
305         void *buf = get_data(size);
307         if (!dry_run && buf)
308                 write_object(nr, type, buf, size);
309         else
310                 free(buf);
313 static int resolve_against_held(unsigned nr, const unsigned char *base,
314                                 void *delta_data, unsigned long delta_size)
316         struct object *obj;
317         struct obj_buffer *obj_buffer;
318         obj = lookup_object(base);
319         if (!obj)
320                 return 0;
321         obj_buffer = lookup_object_buffer(obj);
322         if (!obj_buffer)
323                 return 0;
324         resolve_delta(nr, obj->type, obj_buffer->buffer,
325                       obj_buffer->size, delta_data, delta_size);
326         return 1;
329 static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
330                                unsigned nr)
332         void *delta_data, *base;
333         unsigned long base_size;
334         unsigned char base_sha1[20];
336         if (type == OBJ_REF_DELTA) {
337                 hashcpy(base_sha1, fill(20));
338                 use(20);
339                 delta_data = get_data(delta_size);
340                 if (dry_run || !delta_data) {
341                         free(delta_data);
342                         return;
343                 }
344                 if (has_sha1_file(base_sha1))
345                         ; /* Ok we have this one */
346                 else if (resolve_against_held(nr, base_sha1,
347                                               delta_data, delta_size))
348                         return; /* we are done */
349                 else {
350                         /* cannot resolve yet --- queue it */
351                         hashcpy(obj_list[nr].sha1, null_sha1);
352                         add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
353                         return;
354                 }
355         } else {
356                 unsigned base_found = 0;
357                 unsigned char *pack, c;
358                 off_t base_offset;
359                 unsigned lo, mid, hi;
361                 pack = fill(1);
362                 c = *pack;
363                 use(1);
364                 base_offset = c & 127;
365                 while (c & 128) {
366                         base_offset += 1;
367                         if (!base_offset || MSB(base_offset, 7))
368                                 die("offset value overflow for delta base object");
369                         pack = fill(1);
370                         c = *pack;
371                         use(1);
372                         base_offset = (base_offset << 7) + (c & 127);
373                 }
374                 base_offset = obj_list[nr].offset - base_offset;
375                 if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
376                         die("offset value out of bound for delta base object");
378                 delta_data = get_data(delta_size);
379                 if (dry_run || !delta_data) {
380                         free(delta_data);
381                         return;
382                 }
383                 lo = 0;
384                 hi = nr;
385                 while (lo < hi) {
386                         mid = (lo + hi)/2;
387                         if (base_offset < obj_list[mid].offset) {
388                                 hi = mid;
389                         } else if (base_offset > obj_list[mid].offset) {
390                                 lo = mid + 1;
391                         } else {
392                                 hashcpy(base_sha1, obj_list[mid].sha1);
393                                 base_found = !is_null_sha1(base_sha1);
394                                 break;
395                         }
396                 }
397                 if (!base_found) {
398                         /*
399                          * The delta base object is itself a delta that
400                          * has not been resolved yet.
401                          */
402                         hashcpy(obj_list[nr].sha1, null_sha1);
403                         add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
404                         return;
405                 }
406         }
408         if (resolve_against_held(nr, base_sha1, delta_data, delta_size))
409                 return;
411         base = read_sha1_file(base_sha1, &type, &base_size);
412         if (!base) {
413                 error("failed to read delta-pack base object %s",
414                       sha1_to_hex(base_sha1));
415                 if (!recover)
416                         exit(1);
417                 has_errors = 1;
418                 return;
419         }
420         resolve_delta(nr, type, base, base_size, delta_data, delta_size);
421         free(base);
424 static void unpack_one(unsigned nr)
426         unsigned shift;
427         unsigned char *pack;
428         unsigned long size, c;
429         enum object_type type;
431         obj_list[nr].offset = consumed_bytes;
433         pack = fill(1);
434         c = *pack;
435         use(1);
436         type = (c >> 4) & 7;
437         size = (c & 15);
438         shift = 4;
439         while (c & 0x80) {
440                 pack = fill(1);
441                 c = *pack;
442                 use(1);
443                 size += (c & 0x7f) << shift;
444                 shift += 7;
445         }
447         switch (type) {
448         case OBJ_COMMIT:
449         case OBJ_TREE:
450         case OBJ_BLOB:
451         case OBJ_TAG:
452                 unpack_non_delta_entry(type, size, nr);
453                 return;
454         case OBJ_REF_DELTA:
455         case OBJ_OFS_DELTA:
456                 unpack_delta_entry(type, size, nr);
457                 return;
458         default:
459                 error("bad object type %d", type);
460                 has_errors = 1;
461                 if (recover)
462                         return;
463                 exit(1);
464         }
467 static void unpack_all(void)
469         int i;
470         struct progress *progress = NULL;
471         struct pack_header *hdr = fill(sizeof(struct pack_header));
473         nr_objects = ntohl(hdr->hdr_entries);
475         if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
476                 die("bad pack file");
477         if (!pack_version_ok(hdr->hdr_version))
478                 die("unknown pack file version %"PRIu32,
479                         ntohl(hdr->hdr_version));
480         use(sizeof(struct pack_header));
482         if (!quiet)
483                 progress = start_progress("Unpacking objects", nr_objects);
484         obj_list = xcalloc(nr_objects, sizeof(*obj_list));
485         for (i = 0; i < nr_objects; i++) {
486                 unpack_one(i);
487                 display_progress(progress, i + 1);
488         }
489         stop_progress(&progress);
491         if (delta_list)
492                 die("unresolved deltas left after unpacking");
495 int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
497         int i;
498         unsigned char sha1[20];
500         read_replace_refs = 0;
502         git_config(git_default_config, NULL);
504         quiet = !isatty(2);
506         for (i = 1 ; i < argc; i++) {
507                 const char *arg = argv[i];
509                 if (*arg == '-') {
510                         if (!strcmp(arg, "-n")) {
511                                 dry_run = 1;
512                                 continue;
513                         }
514                         if (!strcmp(arg, "-q")) {
515                                 quiet = 1;
516                                 continue;
517                         }
518                         if (!strcmp(arg, "-r")) {
519                                 recover = 1;
520                                 continue;
521                         }
522                         if (!strcmp(arg, "--strict")) {
523                                 strict = 1;
524                                 continue;
525                         }
526                         if (!prefixcmp(arg, "--pack_header=")) {
527                                 struct pack_header *hdr;
528                                 char *c;
530                                 hdr = (struct pack_header *)buffer;
531                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
532                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
533                                 if (*c != ',')
534                                         die("bad %s", arg);
535                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
536                                 if (*c)
537                                         die("bad %s", arg);
538                                 len = sizeof(*hdr);
539                                 continue;
540                         }
541                         usage(unpack_usage);
542                 }
544                 /* We don't take any non-flag arguments now.. Maybe some day */
545                 usage(unpack_usage);
546         }
547         git_SHA1_Init(&ctx);
548         unpack_all();
549         git_SHA1_Update(&ctx, buffer, offset);
550         git_SHA1_Final(sha1, &ctx);
551         if (strict)
552                 write_rest();
553         if (hashcmp(fill(20), sha1))
554                 die("final sha1 did not match");
555         use(20);
557         /* Write the last part of the buffer to stdout */
558         while (len) {
559                 int ret = xwrite(1, buffer + offset, len);
560                 if (ret <= 0)
561                         break;
562                 len -= ret;
563                 offset += ret;
564         }
566         /* All done */
567         return has_errors;