Merge refs/heads/master from .
[git] / server-info.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "rev-cache.h"
7
8 /* refs */
9 static FILE *info_ref_fp;
10 static unsigned long info_ref_time;
11 static int info_ref_is_stale = 0;
12
13 static int stat_ref(const char *path, const unsigned char *sha1)
14 {
15         struct stat st;
16         if (!stat(path, &st) && info_ref_time < st.st_mtime)
17                 info_ref_is_stale = 1;
18         return 0;
19 }
20
21 static int add_info_ref(const char *path, const unsigned char *sha1)
22 {
23         fprintf(info_ref_fp, "%s        %s\n", sha1_to_hex(sha1), path);
24         return 0;
25 }
26
27 static int update_info_refs(int force)
28 {
29         struct stat st;
30         char *path0 = strdup(git_path("info/refs"));
31         int len = strlen(path0);
32         char *path1 = xmalloc(len + 2);
33
34         strcpy(path1, path0);
35         strcpy(path1 + len, "+");
36
37         if (!force) {
38                 if (stat(path0, &st)) {
39                         if (errno == ENOENT)
40                                 info_ref_is_stale = 1;
41                         else
42                                 return error("cannot stat %s", path0);
43                 }
44                 else {
45                         info_ref_time = st.st_mtime;
46                         for_each_ref(stat_ref);
47                 }
48                 if (!info_ref_is_stale)
49                         return 0;
50         }
51
52         safe_create_leading_directories(path0);
53         info_ref_fp = fopen(path1, "w");
54         if (!info_ref_fp)
55                 return error("unable to update %s", path0);
56         for_each_ref(add_info_ref);
57         fclose(info_ref_fp);
58         rename(path1, path0);
59         free(path0);
60         free(path1);
61         return 0;
62 }
63
64 /* packs */
65 static struct pack_info {
66         unsigned long latest;
67         struct packed_git *p;
68         int old_num;
69         int new_num;
70         int nr_alloc;
71         int nr_heads;
72         unsigned char (*head)[20];
73         char dep[]; /* more */
74 } **info;
75 static int num_pack;
76 static const char *objdir;
77 static int objdirlen;
78
79 static struct object *parse_object_cheap(const unsigned char *sha1)
80 {
81         struct object *o;
82
83         if ((o = parse_object(sha1)) == NULL)
84                 return NULL;
85         if (o->type == commit_type) {
86                 struct commit *commit = (struct commit *)o;
87                 free(commit->buffer);
88                 commit->buffer = NULL;
89         }
90         return o;
91 }
92
93 static struct pack_info *find_pack_by_name(const char *name)
94 {
95         int i;
96         for (i = 0; i < num_pack; i++) {
97                 struct packed_git *p = info[i]->p;
98                 /* skip "/pack/" after ".git/objects" */
99                 if (!strcmp(p->pack_name + objdirlen + 6, name))
100                         return info[i];
101         }
102         return NULL;
103 }
104
105 static struct pack_info *find_pack_by_old_num(int old_num)
106 {
107         int i;
108         for (i = 0; i < num_pack; i++)
109                 if (info[i]->old_num == old_num)
110                         return info[i];
111         return NULL;
112 }
113
114 static int add_head_def(struct pack_info *this, unsigned char *sha1)
115 {
116         if (this->nr_alloc <= this->nr_heads) {
117                 this->nr_alloc = alloc_nr(this->nr_alloc);
118                 this->head = xrealloc(this->head, this->nr_alloc * 20);
119         }
120         memcpy(this->head[this->nr_heads++], sha1, 20);
121         return 0;
122 }
123
124 /* Returns non-zero when we detect that the info in the
125  * old file is useless.
126  */
127 static int parse_pack_def(const char *line, int old_cnt)
128 {
129         struct pack_info *i = find_pack_by_name(line + 2);
130         if (i) {
131                 i->old_num = old_cnt;
132                 return 0;
133         }
134         else {
135                 /* The file describes a pack that is no longer here;
136                  * dependencies between packs needs to be recalculated.
137                  */
138                 return 1;
139         }
140 }
141
142 /* Returns non-zero when we detect that the info in the
143  * old file is useless.
144  */
145 static int parse_depend_def(char *line)
146 {
147         unsigned long num;
148         char *cp, *ep;
149         struct pack_info *this, *that;
150
151         cp = line + 2;
152         num = strtoul(cp, &ep, 10);
153         if (ep == cp)
154                 return error("invalid input %s", line);
155         this = find_pack_by_old_num(num);
156         if (!this)
157                 return 0;
158         while (ep && *(cp = ep)) {
159                 num = strtoul(cp, &ep, 10);
160                 if (ep == cp)
161                         break;
162                 that = find_pack_by_old_num(num);
163                 if (!that)
164                         /* The pack this one depends on does not
165                          * exist; this should not happen because
166                          * we write out the list of packs first and
167                          * then dependency information, but it means
168                          * the file is useless anyway.
169                          */
170                         return 1;
171                 this->dep[that->new_num] = 1;
172         }
173         return 0;
174 }
175
176 /* Returns non-zero when we detect that the info in the
177  * old file is useless.
178  */
179 static int parse_head_def(char *line)
180 {
181         unsigned char sha1[20];
182         unsigned long num;
183         char *cp, *ep;
184         struct pack_info *this;
185         struct object *o;
186
187         cp = line + 2;
188         num = strtoul(cp, &ep, 10);
189         if (ep == cp || *ep++ != ' ')
190                 return error("invalid input ix %s", line);
191         this = find_pack_by_old_num(num);
192         if (!this)
193                 return 1; /* You know the drill. */
194         if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
195                 return error("invalid input sha1 %s (%s)", line, ep);
196         if ((o = parse_object_cheap(sha1)) == NULL)
197                 return error("no such object: %s", line);
198         return add_head_def(this, sha1);
199 }
200
201 /* Returns non-zero when we detect that the info in the
202  * old file is useless.
203  */
204 static int read_pack_info_file(const char *infofile)
205 {
206         FILE *fp;
207         char line[1000];
208         int old_cnt = 0;
209
210         fp = fopen(infofile, "r");
211         if (!fp)
212                 return 1; /* nonexisting is not an error. */
213
214         while (fgets(line, sizeof(line), fp)) {
215                 int len = strlen(line);
216                 if (line[len-1] == '\n')
217                         line[len-1] = 0;
218
219                 switch (line[0]) {
220                 case 'P': /* P name */
221                         if (parse_pack_def(line, old_cnt++))
222                                 goto out_stale;
223                         break;
224                 case 'D': /* D ix dep-ix1 dep-ix2... */
225                         if (parse_depend_def(line))
226                                 goto out_stale;
227                         break;
228                 case 'T': /* T ix sha1 type */
229                         if (parse_head_def(line))
230                                 goto out_stale;
231                         break;
232                 default:
233                         error("unrecognized: %s", line);
234                         break;
235                 }
236         }
237         fclose(fp);
238         return 0;
239  out_stale:
240         fclose(fp);
241         return 1;
242 }
243
244 /* We sort the packs according to the date of the latest commit.  That
245  * in turn indicates how young the pack is, and in general we would
246  * want to depend on younger packs.
247  */
248 static unsigned long get_latest_commit_date(struct packed_git *p)
249 {
250         unsigned char sha1[20];
251         struct object *o;
252         int num = num_packed_objects(p);
253         int i;
254         unsigned long latest = 0;
255
256         for (i = 0; i < num; i++) {
257                 if (nth_packed_object_sha1(p, i, sha1))
258                         die("corrupt pack file %s?", p->pack_name);
259                 if ((o = parse_object_cheap(sha1)) == NULL)
260                         die("cannot parse %s", sha1_to_hex(sha1));
261                 if (o->type == commit_type) {
262                         struct commit *commit = (struct commit *)o;
263                         if (latest < commit->date)
264                                 latest = commit->date;
265                 }
266         }
267         return latest;
268 }
269
270 static int compare_info(const void *a_, const void *b_)
271 {
272         struct pack_info * const* a = a_;
273         struct pack_info * const* b = b_;
274
275         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
276                 /* Keep the order in the original */
277                 return (*a)->old_num - (*b)->old_num;
278         else if (0 <= (*a)->old_num)
279                 /* Only A existed in the original so B is obviously newer */
280                 return -1;
281         else if (0 <= (*b)->old_num)
282                 /* The other way around. */
283                 return 1;
284
285         if ((*a)->latest < (*b)->latest)
286                 return -1;
287         else if ((*a)->latest == (*b)->latest)
288                 return 0;
289         else
290                 return 1;
291 }
292
293 static void init_pack_info(const char *infofile, int force)
294 {
295         struct packed_git *p;
296         int stale;
297         int i = 0;
298         char *dep_temp;
299
300         objdir = get_object_directory();
301         objdirlen = strlen(objdir);
302
303         prepare_packed_git();
304         for (p = packed_git; p; p = p->next) {
305                 /* we ignore things on alternate path since they are
306                  * not available to the pullers in general.
307                  */
308                 if (strncmp(p->pack_name, objdir, objdirlen) ||
309                     strncmp(p->pack_name + objdirlen, "/pack/", 6))
310                         continue;
311                 i++;
312         }
313         num_pack = i;
314         info = xcalloc(num_pack, sizeof(struct pack_info *));
315         for (i = 0, p = packed_git; p; p = p->next) {
316                 if (strncmp(p->pack_name, objdir, objdirlen) ||
317                     p->pack_name[objdirlen] != '/')
318                         continue;
319                 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
320                 info[i]->p = p;
321                 info[i]->old_num = -1;
322                 i++;
323         }
324
325         if (infofile && !force)
326                 stale = read_pack_info_file(infofile);
327         else
328                 stale = 1;
329
330         for (i = 0; i < num_pack; i++) {
331                 if (stale) {
332                         info[i]->old_num = -1;
333                         memset(info[i]->dep, 0, num_pack);
334                         info[i]->nr_heads = 0;
335                 }
336                 if (info[i]->old_num < 0)
337                         info[i]->latest = get_latest_commit_date(info[i]->p);
338         }
339
340         qsort(info, num_pack, sizeof(info[0]), compare_info);
341         for (i = 0; i < num_pack; i++)
342                 info[i]->new_num = i;
343
344         /* we need to fix up the dependency information
345          * for the old ones.
346          */
347         dep_temp = NULL;
348         for (i = 0; i < num_pack; i++) {
349                 int old;
350
351                 if (info[i]->old_num < 0)
352                         continue;
353                 if (! dep_temp)
354                         dep_temp = xmalloc(num_pack);
355                 memset(dep_temp, 0, num_pack);
356                 for (old = 0; old < num_pack; old++) {
357                         struct pack_info *base;
358                         if (!info[i]->dep[old])
359                                 continue;
360                         base = find_pack_by_old_num(old);
361                         if (!base)
362                                 die("internal error renumbering");
363                         dep_temp[base->new_num] = 1;
364                 }
365                 memcpy(info[i]->dep, dep_temp, num_pack);
366         }
367         free(dep_temp);
368 }
369
370 static void write_pack_info_file(FILE *fp)
371 {
372         int i, j;
373         for (i = 0; i < num_pack; i++)
374                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
375
376         for (i = 0; i < num_pack; i++) {
377                 fprintf(fp, "D %1d", i);
378                 for (j = 0; j < num_pack; j++) {
379                         if ((i == j) || !(info[i]->dep[j]))
380                                 continue;
381                         fprintf(fp, " %1d", j);
382                 }
383                 fputc('\n', fp);
384         }
385
386         for (i = 0; i < num_pack; i++) {
387                 struct pack_info *this = info[i];
388                 for (j = 0; j < this->nr_heads; j++) {
389                         struct object *o = lookup_object(this->head[j]);
390                         fprintf(fp, "T %1d %s %s\n",
391                                 i, sha1_to_hex(this->head[j]), o->type);
392                 }
393         }
394
395 }
396
397 #define REFERENCED 01
398 #define INTERNAL  02
399 #define EMITTED   04
400
401 static void show(struct object *o, int pack_ix)
402 {
403         /*
404          * We are interested in objects that are not referenced,
405          * and objects that are referenced but not internal.
406          */
407         if (o->flags & EMITTED)
408                 return;
409
410         if (!(o->flags & REFERENCED))
411                 add_head_def(info[pack_ix], o->sha1);
412         else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
413                 int i;
414
415                 /* Which pack contains this object?  That is what
416                  * pack_ix can depend on.  We earlier sorted info
417                  * array from youngest to oldest, so try newer packs
418                  * first to favor them here.
419                  */
420                 for (i = num_pack - 1; 0 <= i; i--) {
421                         struct packed_git *p = info[i]->p;
422                         struct pack_entry ent;
423                         if (find_pack_entry_one(o->sha1, &ent, p)) {
424                                 info[pack_ix]->dep[i] = 1;
425                                 break;
426                         }
427                 }
428         }
429         o->flags |= EMITTED;
430 }
431
432 static void find_pack_info_one(int pack_ix)
433 {
434         unsigned char sha1[20];
435         struct object *o;
436         struct object_list *ref;
437         int i;
438         struct packed_git *p = info[pack_ix]->p;
439         int num = num_packed_objects(p);
440
441         /* Scan objects, clear flags from all the edge ones and
442          * internal ones, possibly marked in the previous round.
443          */
444         for (i = 0; i < num; i++) {
445                 if (nth_packed_object_sha1(p, i, sha1))
446                         die("corrupt pack file %s?", p->pack_name);
447                 if ((o = lookup_object(sha1)) == NULL)
448                         die("cannot parse %s", sha1_to_hex(sha1));
449                 for (ref = o->refs; ref; ref = ref->next)
450                         ref->item->flags = 0;
451                 o->flags = 0;
452         }
453
454         /* Mark all the internal ones */
455         for (i = 0; i < num; i++) {
456                 if (nth_packed_object_sha1(p, i, sha1))
457                         die("corrupt pack file %s?", p->pack_name);
458                 if ((o = lookup_object(sha1)) == NULL)
459                         die("cannot find %s", sha1_to_hex(sha1));
460                 for (ref = o->refs; ref; ref = ref->next)
461                         ref->item->flags |= REFERENCED;
462                 o->flags |= INTERNAL;
463         }
464
465         for (i = 0; i < num; i++) {
466                 if (nth_packed_object_sha1(p, i, sha1))
467                         die("corrupt pack file %s?", p->pack_name);
468                 if ((o = lookup_object(sha1)) == NULL)
469                         die("cannot find %s", sha1_to_hex(sha1));
470
471                 show(o, pack_ix);
472                 for (ref = o->refs; ref; ref = ref->next)
473                         show(ref->item, pack_ix);
474         }
475
476 }
477
478 static void find_pack_info(void)
479 {
480         int i;
481         for (i = 0; i < num_pack; i++) {
482                 /* The packed objects are cast in stone, and a head
483                  * in a pack will stay as head, so is the set of missing
484                  * objects.  If the repo has been reorganized and we
485                  * are missing some packs available back then, we have
486                  * already discarded the info read from the file, so
487                  * we will find (old_num < 0) in that case.
488                  */
489                 if (0 <= info[i]->old_num)
490                         continue;
491                 find_pack_info_one(i);
492         }
493 }
494
495 static int update_info_packs(int force)
496 {
497         char infofile[PATH_MAX];
498         char name[PATH_MAX];
499         int namelen;
500         FILE *fp;
501
502         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
503         strcpy(name, infofile);
504         strcpy(name + namelen, "+");
505
506         init_pack_info(infofile, force);
507         find_pack_info();
508
509         safe_create_leading_directories(name);
510         fp = fopen(name, "w");
511         if (!fp)
512                 return error("cannot open %s", name);
513         write_pack_info_file(fp);
514         fclose(fp);
515         rename(name, infofile);
516         return 0;
517 }
518
519 /* rev-cache */
520 static int record_rev_cache_ref(const char *path, const unsigned char *sha1)
521 {
522         struct object *obj = parse_object(sha1);
523
524         if (!obj)
525                 return error("ref %s has bad sha %s", path, sha1_to_hex(sha1));
526         while (obj && obj->type == tag_type)
527                 obj = parse_object(((struct tag *)obj)->tagged->sha1);
528         if (!obj || obj->type != commit_type)
529                 /* tag pointing at a non-commit */
530                 return 0;
531         return record_rev_cache(obj->sha1, NULL);
532 }
533
534 static int update_info_revs(int force)
535 {
536         char *path0 = strdup(git_path("info/rev-cache"));
537         int len = strlen(path0);
538         char *path1 = xmalloc(len + 2);
539
540         strcpy(path1, path0);
541         strcpy(path1 + len, "+");
542
543         /* read existing rev-cache */
544         if (!force)
545                 read_rev_cache(path0, NULL, 0);
546         safe_create_leading_directories(path0);
547
548         for_each_ref(record_rev_cache_ref);
549
550         /* update the rev-cache database */
551         write_rev_cache(path1, force ? "/dev/null" : path0);
552         rename(path1, path0);
553         free(path1);
554         free(path0);
555         return 0;
556 }
557
558 /* public */
559 int update_server_info(int force)
560 {
561         /* We would add more dumb-server support files later,
562          * including index of available pack files and their
563          * intended audiences.
564          */
565         int errs = 0;
566
567         errs = errs | update_info_refs(force);
568         errs = errs | update_info_packs(force);
569         errs = errs | update_info_revs(force);
570
571         return errs;
572 }