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/* refs */
9static FILE *info_ref_fp;
10static unsigned long info_ref_time;
11static int info_ref_is_stale = 0;
12static 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}
20static 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}
26static 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 strcpy(path1, path0);
35 strcpy(path1 + len, "+");
36 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 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/* packs */
65struct 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[0]; /* more */
74} **info;
75static int num_pack;
76static const char *objdir;
77static int objdirlen;
78static struct object *parse_object_cheap(const unsigned char *sha1)
80{
81 struct object *o;
82 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}
92static 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}
104static 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}
113static 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/* Returns non-zero when we detect that the info in the
125 * old file is useless.
126 */
127static 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/* Returns non-zero when we detect that the info in the
143 * old file is useless.
144 */
145static int parse_depend_def(char *line)
146{
147 unsigned long num;
148 char *cp, *ep;
149 struct pack_info *this, *that;
150 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/* Returns non-zero when we detect that the info in the
177 * old file is useless.
178 */
179static 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 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/* Returns non-zero when we detect that the info in the
202 * old file is useless.
203 */
204static int read_pack_info_file(const char *infofile)
205{
206 FILE *fp;
207 char line[1000];
208 int old_cnt = 0;
209 fp = fopen(infofile, "r");
211 if (!fp)
212 return 1; /* nonexisting is not an error. */
213 while (fgets(line, sizeof(line), fp)) {
215 int len = strlen(line);
216 if (line[len-1] == '\n')
217 line[len-1] = 0;
218 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/* 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 */
248static 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 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}
269static 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 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 if ((*a)->latest < (*b)->latest)
286 return -1;
287 else if ((*a)->latest == (*b)->latest)
288 return 0;
289 else
290 return 1;
291}
292static 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 objdir = get_object_directory();
301 objdirlen = strlen(objdir);
302 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 if (infofile && !force)
326 stale = read_pack_info_file(infofile);
327 else
328 stale = 1;
329 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 qsort(info, num_pack, sizeof(info[0]), compare_info);
341 for (i = 0; i < num_pack; i++)
342 info[i]->new_num = i;
343 /* 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 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}
369static 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 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 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}
396#define REFERENCED 01
398#define INTERNAL 02
399#define EMITTED 04
400static 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 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 /* 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}
431static 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 /* 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 /* 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 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 show(o, pack_ix);
472 for (ref = o->refs; ref; ref = ref->next)
473 show(ref->item, pack_ix);
474 }
475}
477static 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}
494static int update_info_packs(int force)
496{
497 char infofile[PATH_MAX];
498 char name[PATH_MAX];
499 int namelen;
500 FILE *fp;
501 namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
503 strcpy(name, infofile);
504 strcpy(name + namelen, "+");
505 init_pack_info(infofile, force);
507 find_pack_info();
508 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/* rev-cache */
520static int record_rev_cache_ref(const char *path, const unsigned char *sha1)
521{
522 struct object *obj = parse_object(sha1);
523 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}
533static 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 strcpy(path1, path0);
541 strcpy(path1 + len, "+");
542 /* read existing rev-cache */
544 if (!force)
545 read_rev_cache(path0, NULL, 0);
546 safe_create_leading_directories(path0);
547 for_each_ref(record_rev_cache_ref);
549 /* 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/* public */
559int 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 errs = errs | update_info_refs(force);
568 errs = errs | update_info_packs(force);
569 errs = errs | update_info_revs(force);
570 return errs;
572}