ba5359108deb4f010be366ef65974ec7db123098
[git/git.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
7 /* refs */
8 static FILE *info_ref_fp;
9
10 static int add_info_ref(const char *path, const unsigned char *sha1)
11 {
12 struct object *o = parse_object(sha1);
13
14 fprintf(info_ref_fp, "%s %s\n", sha1_to_hex(sha1), path);
15 if (o->type == tag_type) {
16 o = deref_tag(o);
17 fprintf(info_ref_fp, "%s %s^{}\n",
18 sha1_to_hex(o->sha1), path);
19 }
20 return 0;
21 }
22
23 static int update_info_refs(int force)
24 {
25 char *path0 = strdup(git_path("info/refs"));
26 int len = strlen(path0);
27 char *path1 = xmalloc(len + 2);
28
29 strcpy(path1, path0);
30 strcpy(path1 + len, "+");
31
32 safe_create_leading_directories(path0);
33 info_ref_fp = fopen(path1, "w");
34 if (!info_ref_fp)
35 return error("unable to update %s", path0);
36 for_each_ref(add_info_ref);
37 fclose(info_ref_fp);
38 rename(path1, path0);
39 free(path0);
40 free(path1);
41 return 0;
42 }
43
44 /* packs */
45 static struct pack_info {
46 unsigned long latest;
47 struct packed_git *p;
48 int old_num;
49 int new_num;
50 int nr_alloc;
51 int nr_heads;
52 unsigned char (*head)[20];
53 char dep[0]; /* more */
54 } **info;
55 static int num_pack;
56 static const char *objdir;
57 static int objdirlen;
58
59 static struct object *parse_object_cheap(const unsigned char *sha1)
60 {
61 struct object *o;
62
63 if ((o = parse_object(sha1)) == NULL)
64 return NULL;
65 if (o->type == commit_type) {
66 struct commit *commit = (struct commit *)o;
67 free(commit->buffer);
68 commit->buffer = NULL;
69 } else if (o->type == tree_type) {
70 struct tree *tree = (struct tree *)o;
71 struct tree_entry_list *e, *n;
72 for (e = tree->entries; e; e = n) {
73 free(e->name);
74 e->name = NULL;
75 n = e->next;
76 free(e);
77 }
78 tree->entries = NULL;
79 }
80 return o;
81 }
82
83 static struct pack_info *find_pack_by_name(const char *name)
84 {
85 int i;
86 for (i = 0; i < num_pack; i++) {
87 struct packed_git *p = info[i]->p;
88 /* skip "/pack/" after ".git/objects" */
89 if (!strcmp(p->pack_name + objdirlen + 6, name))
90 return info[i];
91 }
92 return NULL;
93 }
94
95 static struct pack_info *find_pack_by_old_num(int old_num)
96 {
97 int i;
98 for (i = 0; i < num_pack; i++)
99 if (info[i]->old_num == old_num)
100 return info[i];
101 return NULL;
102 }
103
104 static int add_head_def(struct pack_info *this, unsigned char *sha1)
105 {
106 if (this->nr_alloc <= this->nr_heads) {
107 this->nr_alloc = alloc_nr(this->nr_alloc);
108 this->head = xrealloc(this->head, this->nr_alloc * 20);
109 }
110 memcpy(this->head[this->nr_heads++], sha1, 20);
111 return 0;
112 }
113
114 /* Returns non-zero when we detect that the info in the
115 * old file is useless.
116 */
117 static int parse_pack_def(const char *line, int old_cnt)
118 {
119 struct pack_info *i = find_pack_by_name(line + 2);
120 if (i) {
121 i->old_num = old_cnt;
122 return 0;
123 }
124 else {
125 /* The file describes a pack that is no longer here;
126 * dependencies between packs needs to be recalculated.
127 */
128 return 1;
129 }
130 }
131
132 /* Returns non-zero when we detect that the info in the
133 * old file is useless.
134 */
135 static int parse_depend_def(char *line)
136 {
137 unsigned long num;
138 char *cp, *ep;
139 struct pack_info *this, *that;
140
141 cp = line + 2;
142 num = strtoul(cp, &ep, 10);
143 if (ep == cp)
144 return error("invalid input %s", line);
145 this = find_pack_by_old_num(num);
146 if (!this)
147 return 0;
148 while (ep && *(cp = ep)) {
149 num = strtoul(cp, &ep, 10);
150 if (ep == cp)
151 break;
152 that = find_pack_by_old_num(num);
153 if (!that)
154 /* The pack this one depends on does not
155 * exist; this should not happen because
156 * we write out the list of packs first and
157 * then dependency information, but it means
158 * the file is useless anyway.
159 */
160 return 1;
161 this->dep[that->new_num] = 1;
162 }
163 return 0;
164 }
165
166 /* Returns non-zero when we detect that the info in the
167 * old file is useless.
168 */
169 static int parse_head_def(char *line)
170 {
171 unsigned char sha1[20];
172 unsigned long num;
173 char *cp, *ep;
174 struct pack_info *this;
175 struct object *o;
176
177 cp = line + 2;
178 num = strtoul(cp, &ep, 10);
179 if (ep == cp || *ep++ != ' ')
180 return error("invalid input ix %s", line);
181 this = find_pack_by_old_num(num);
182 if (!this)
183 return 1; /* You know the drill. */
184 if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
185 return error("invalid input sha1 %s (%s)", line, ep);
186 if ((o = parse_object_cheap(sha1)) == NULL)
187 return error("no such object: %s", line);
188 return add_head_def(this, sha1);
189 }
190
191 /* Returns non-zero when we detect that the info in the
192 * old file is useless.
193 */
194 static int read_pack_info_file(const char *infofile)
195 {
196 FILE *fp;
197 char line[1000];
198 int old_cnt = 0;
199
200 fp = fopen(infofile, "r");
201 if (!fp)
202 return 1; /* nonexisting is not an error. */
203
204 while (fgets(line, sizeof(line), fp)) {
205 int len = strlen(line);
206 if (line[len-1] == '\n')
207 line[len-1] = 0;
208
209 switch (line[0]) {
210 case 'P': /* P name */
211 if (parse_pack_def(line, old_cnt++))
212 goto out_stale;
213 break;
214 case 'D': /* D ix dep-ix1 dep-ix2... */
215 if (parse_depend_def(line))
216 goto out_stale;
217 break;
218 case 'T': /* T ix sha1 type */
219 if (parse_head_def(line))
220 goto out_stale;
221 break;
222 default:
223 error("unrecognized: %s", line);
224 break;
225 }
226 }
227 fclose(fp);
228 return 0;
229 out_stale:
230 fclose(fp);
231 return 1;
232 }
233
234 /* We sort the packs according to the date of the latest commit. That
235 * in turn indicates how young the pack is, and in general we would
236 * want to depend on younger packs.
237 */
238 static unsigned long get_latest_commit_date(struct packed_git *p)
239 {
240 unsigned char sha1[20];
241 struct object *o;
242 int num = num_packed_objects(p);
243 int i;
244 unsigned long latest = 0;
245
246 for (i = 0; i < num; i++) {
247 if (nth_packed_object_sha1(p, i, sha1))
248 die("corrupt pack file %s?", p->pack_name);
249 if ((o = parse_object_cheap(sha1)) == NULL)
250 die("cannot parse %s", sha1_to_hex(sha1));
251 if (o->type == commit_type) {
252 struct commit *commit = (struct commit *)o;
253 if (latest < commit->date)
254 latest = commit->date;
255 }
256 }
257 return latest;
258 }
259
260 static int compare_info(const void *a_, const void *b_)
261 {
262 struct pack_info * const* a = a_;
263 struct pack_info * const* b = b_;
264
265 if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
266 /* Keep the order in the original */
267 return (*a)->old_num - (*b)->old_num;
268 else if (0 <= (*a)->old_num)
269 /* Only A existed in the original so B is obviously newer */
270 return -1;
271 else if (0 <= (*b)->old_num)
272 /* The other way around. */
273 return 1;
274
275 if ((*a)->latest < (*b)->latest)
276 return -1;
277 else if ((*a)->latest == (*b)->latest)
278 return 0;
279 else
280 return 1;
281 }
282
283 static void init_pack_info(const char *infofile, int force)
284 {
285 struct packed_git *p;
286 int stale;
287 int i = 0;
288 char *dep_temp;
289
290 objdir = get_object_directory();
291 objdirlen = strlen(objdir);
292
293 prepare_packed_git();
294 for (p = packed_git; p; p = p->next) {
295 /* we ignore things on alternate path since they are
296 * not available to the pullers in general.
297 */
298 if (strncmp(p->pack_name, objdir, objdirlen) ||
299 strncmp(p->pack_name + objdirlen, "/pack/", 6))
300 continue;
301 i++;
302 }
303 num_pack = i;
304 info = xcalloc(num_pack, sizeof(struct pack_info *));
305 for (i = 0, p = packed_git; p; p = p->next) {
306 if (strncmp(p->pack_name, objdir, objdirlen) ||
307 p->pack_name[objdirlen] != '/')
308 continue;
309 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
310 info[i]->p = p;
311 info[i]->old_num = -1;
312 i++;
313 }
314
315 if (infofile && !force)
316 stale = read_pack_info_file(infofile);
317 else
318 stale = 1;
319
320 for (i = 0; i < num_pack; i++) {
321 if (stale) {
322 info[i]->old_num = -1;
323 memset(info[i]->dep, 0, num_pack);
324 info[i]->nr_heads = 0;
325 }
326 if (info[i]->old_num < 0)
327 info[i]->latest = get_latest_commit_date(info[i]->p);
328 }
329
330 qsort(info, num_pack, sizeof(info[0]), compare_info);
331 for (i = 0; i < num_pack; i++)
332 info[i]->new_num = i;
333
334 /* we need to fix up the dependency information
335 * for the old ones.
336 */
337 dep_temp = NULL;
338 for (i = 0; i < num_pack; i++) {
339 int old;
340
341 if (info[i]->old_num < 0)
342 continue;
343 if (! dep_temp)
344 dep_temp = xmalloc(num_pack);
345 memset(dep_temp, 0, num_pack);
346 for (old = 0; old < num_pack; old++) {
347 struct pack_info *base;
348 if (!info[i]->dep[old])
349 continue;
350 base = find_pack_by_old_num(old);
351 if (!base)
352 die("internal error renumbering");
353 dep_temp[base->new_num] = 1;
354 }
355 memcpy(info[i]->dep, dep_temp, num_pack);
356 }
357 free(dep_temp);
358 }
359
360 static void write_pack_info_file(FILE *fp)
361 {
362 int i, j;
363 for (i = 0; i < num_pack; i++)
364 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
365
366 for (i = 0; i < num_pack; i++) {
367 fprintf(fp, "D %1d", i);
368 for (j = 0; j < num_pack; j++) {
369 if ((i == j) || !(info[i]->dep[j]))
370 continue;
371 fprintf(fp, " %1d", j);
372 }
373 fputc('\n', fp);
374 }
375
376 for (i = 0; i < num_pack; i++) {
377 struct pack_info *this = info[i];
378 for (j = 0; j < this->nr_heads; j++) {
379 struct object *o = lookup_object(this->head[j]);
380 fprintf(fp, "T %1d %s %s\n",
381 i, sha1_to_hex(this->head[j]), o->type);
382 }
383 }
384
385 }
386
387 #define REFERENCED 01
388 #define INTERNAL 02
389 #define EMITTED 04
390
391 static void show(struct object *o, int pack_ix)
392 {
393 /*
394 * We are interested in objects that are not referenced,
395 * and objects that are referenced but not internal.
396 */
397 if (o->flags & EMITTED)
398 return;
399
400 if (!(o->flags & REFERENCED))
401 add_head_def(info[pack_ix], o->sha1);
402 else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
403 int i;
404
405 /* Which pack contains this object? That is what
406 * pack_ix can depend on. We earlier sorted info
407 * array from youngest to oldest, so try newer packs
408 * first to favor them here.
409 */
410 for (i = num_pack - 1; 0 <= i; i--) {
411 struct packed_git *p = info[i]->p;
412 struct pack_entry ent;
413 if (find_pack_entry_one(o->sha1, &ent, p)) {
414 info[pack_ix]->dep[i] = 1;
415 break;
416 }
417 }
418 }
419 o->flags |= EMITTED;
420 }
421
422 static void find_pack_info_one(int pack_ix)
423 {
424 unsigned char sha1[20];
425 struct object *o;
426 struct object_list *ref;
427 int i;
428 struct packed_git *p = info[pack_ix]->p;
429 int num = num_packed_objects(p);
430
431 /* Scan objects, clear flags from all the edge ones and
432 * internal ones, possibly marked in the previous round.
433 */
434 for (i = 0; i < num; i++) {
435 if (nth_packed_object_sha1(p, i, sha1))
436 die("corrupt pack file %s?", p->pack_name);
437 if ((o = lookup_object(sha1)) == NULL)
438 die("cannot parse %s", sha1_to_hex(sha1));
439 for (ref = o->refs; ref; ref = ref->next)
440 ref->item->flags = 0;
441 o->flags = 0;
442 }
443
444 /* Mark all the internal ones */
445 for (i = 0; i < num; i++) {
446 if (nth_packed_object_sha1(p, i, sha1))
447 die("corrupt pack file %s?", p->pack_name);
448 if ((o = lookup_object(sha1)) == NULL)
449 die("cannot find %s", sha1_to_hex(sha1));
450 for (ref = o->refs; ref; ref = ref->next)
451 ref->item->flags |= REFERENCED;
452 o->flags |= INTERNAL;
453 }
454
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
461 show(o, pack_ix);
462 for (ref = o->refs; ref; ref = ref->next)
463 show(ref->item, pack_ix);
464 }
465
466 }
467
468 static void find_pack_info(void)
469 {
470 int i;
471 for (i = 0; i < num_pack; i++) {
472 /* The packed objects are cast in stone, and a head
473 * in a pack will stay as head, so is the set of missing
474 * objects. If the repo has been reorganized and we
475 * are missing some packs available back then, we have
476 * already discarded the info read from the file, so
477 * we will find (old_num < 0) in that case.
478 */
479 if (0 <= info[i]->old_num)
480 continue;
481 find_pack_info_one(i);
482 }
483 }
484
485 static int update_info_packs(int force)
486 {
487 char infofile[PATH_MAX];
488 char name[PATH_MAX];
489 int namelen;
490 FILE *fp;
491
492 namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
493 strcpy(name, infofile);
494 strcpy(name + namelen, "+");
495
496 init_pack_info(infofile, force);
497 find_pack_info();
498
499 safe_create_leading_directories(name);
500 fp = fopen(name, "w");
501 if (!fp)
502 return error("cannot open %s", name);
503 write_pack_info_file(fp);
504 fclose(fp);
505 rename(name, infofile);
506 return 0;
507 }
508
509 /* public */
510 int update_server_info(int force)
511 {
512 /* We would add more dumb-server support files later,
513 * including index of available pack files and their
514 * intended audiences.
515 */
516 int errs = 0;
517
518 errs = errs | update_info_refs(force);
519 errs = errs | update_info_packs(force);
520
521 return errs;
522 }