Merge branch 'dl/format-patch-notes-config-fixup'
[git] / server-info.c
1 #include "cache.h"
2 #include "dir.h"
3 #include "repository.h"
4 #include "refs.h"
5 #include "object.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "packfile.h"
9 #include "object-store.h"
10 #include "strbuf.h"
11
12 struct update_info_ctx {
13         FILE *cur_fp;
14         FILE *old_fp; /* becomes NULL if it differs from cur_fp */
15         struct strbuf cur_sb;
16         struct strbuf old_sb;
17 };
18
19 static void uic_mark_stale(struct update_info_ctx *uic)
20 {
21         fclose(uic->old_fp);
22         uic->old_fp = NULL;
23 }
24
25 static int uic_is_stale(const struct update_info_ctx *uic)
26 {
27         return uic->old_fp == NULL;
28 }
29
30 static int uic_printf(struct update_info_ctx *uic, const char *fmt, ...)
31 {
32         va_list ap;
33         int ret = -1;
34
35         va_start(ap, fmt);
36
37         if (uic_is_stale(uic)) {
38                 ret = vfprintf(uic->cur_fp, fmt, ap);
39         } else {
40                 ssize_t r;
41                 struct strbuf *cur = &uic->cur_sb;
42                 struct strbuf *old = &uic->old_sb;
43
44                 strbuf_reset(cur);
45                 strbuf_vinsertf(cur, 0, fmt, ap);
46
47                 strbuf_reset(old);
48                 strbuf_grow(old, cur->len);
49                 r = fread(old->buf, 1, cur->len, uic->old_fp);
50                 if (r != cur->len || memcmp(old->buf, cur->buf, r))
51                         uic_mark_stale(uic);
52
53                 if (fwrite(cur->buf, 1, cur->len, uic->cur_fp) == cur->len)
54                         ret = 0;
55         }
56
57         va_end(ap);
58
59         return ret;
60 }
61
62 /*
63  * Create the file "path" by writing to a temporary file and renaming
64  * it into place. The contents of the file come from "generate", which
65  * should return non-zero if it encounters an error.
66  */
67 static int update_info_file(char *path,
68                         int (*generate)(struct update_info_ctx *),
69                         int force)
70 {
71         char *tmp = mkpathdup("%s_XXXXXX", path);
72         int ret = -1;
73         int fd = -1;
74         FILE *to_close;
75         struct update_info_ctx uic = {
76                 .cur_fp = NULL,
77                 .old_fp = NULL,
78                 .cur_sb = STRBUF_INIT,
79                 .old_sb = STRBUF_INIT
80         };
81
82         safe_create_leading_directories(path);
83         fd = git_mkstemp_mode(tmp, 0666);
84         if (fd < 0)
85                 goto out;
86         to_close = uic.cur_fp = fdopen(fd, "w");
87         if (!uic.cur_fp)
88                 goto out;
89         fd = -1;
90
91         /* no problem on ENOENT and old_fp == NULL, it's stale, now */
92         if (!force)
93                 uic.old_fp = fopen_or_warn(path, "r");
94
95         /*
96          * uic_printf will compare incremental comparison against old_fp
97          * and mark uic as stale if needed
98          */
99         ret = generate(&uic);
100         if (ret)
101                 goto out;
102
103         /* new file may be shorter than the old one, check here */
104         if (!uic_is_stale(&uic)) {
105                 struct stat st;
106                 long new_len = ftell(uic.cur_fp);
107                 int old_fd = fileno(uic.old_fp);
108
109                 if (new_len < 0) {
110                         ret = -1;
111                         goto out;
112                 }
113                 if (fstat(old_fd, &st) || (st.st_size != (size_t)new_len))
114                         uic_mark_stale(&uic);
115         }
116
117         uic.cur_fp = NULL;
118         if (fclose(to_close))
119                 goto out;
120
121         if (uic_is_stale(&uic)) {
122                 if (adjust_shared_perm(tmp) < 0)
123                         goto out;
124                 if (rename(tmp, path) < 0)
125                         goto out;
126         } else {
127                 unlink(tmp);
128         }
129         ret = 0;
130
131 out:
132         if (ret) {
133                 error_errno("unable to update %s", path);
134                 if (uic.cur_fp)
135                         fclose(uic.cur_fp);
136                 else if (fd >= 0)
137                         close(fd);
138                 unlink(tmp);
139         }
140         free(tmp);
141         if (uic.old_fp)
142                 fclose(uic.old_fp);
143         strbuf_release(&uic.old_sb);
144         strbuf_release(&uic.cur_sb);
145         return ret;
146 }
147
148 static int add_info_ref(const char *path, const struct object_id *oid,
149                         int flag, void *cb_data)
150 {
151         struct update_info_ctx *uic = cb_data;
152         struct object *o = parse_object(the_repository, oid);
153         if (!o)
154                 return -1;
155
156         if (uic_printf(uic, "%s %s\n", oid_to_hex(oid), path) < 0)
157                 return -1;
158
159         if (o->type == OBJ_TAG) {
160                 o = deref_tag(the_repository, o, path, 0);
161                 if (o)
162                         if (uic_printf(uic, "%s %s^{}\n",
163                                 oid_to_hex(&o->oid), path) < 0)
164                                 return -1;
165         }
166         return 0;
167 }
168
169 static int generate_info_refs(struct update_info_ctx *uic)
170 {
171         return for_each_ref(add_info_ref, uic);
172 }
173
174 static int update_info_refs(int force)
175 {
176         char *path = git_pathdup("info/refs");
177         int ret = update_info_file(path, generate_info_refs, force);
178         free(path);
179         return ret;
180 }
181
182 /* packs */
183 static struct pack_info {
184         struct packed_git *p;
185         int old_num;
186         int new_num;
187 } **info;
188 static int num_pack;
189
190 static struct pack_info *find_pack_by_name(const char *name)
191 {
192         int i;
193         for (i = 0; i < num_pack; i++) {
194                 struct packed_git *p = info[i]->p;
195                 if (!strcmp(pack_basename(p), name))
196                         return info[i];
197         }
198         return NULL;
199 }
200
201 /* Returns non-zero when we detect that the info in the
202  * old file is useless.
203  */
204 static int parse_pack_def(const char *packname, int old_cnt)
205 {
206         struct pack_info *i = find_pack_by_name(packname);
207         if (i) {
208                 i->old_num = old_cnt;
209                 return 0;
210         }
211         else {
212                 /* The file describes a pack that is no longer here */
213                 return 1;
214         }
215 }
216
217 /* Returns non-zero when we detect that the info in the
218  * old file is useless.
219  */
220 static int read_pack_info_file(const char *infofile)
221 {
222         FILE *fp;
223         struct strbuf line = STRBUF_INIT;
224         int old_cnt = 0;
225         int stale = 1;
226
227         fp = fopen_or_warn(infofile, "r");
228         if (!fp)
229                 return 1; /* nonexistent is not an error. */
230
231         while (strbuf_getline(&line, fp) != EOF) {
232                 const char *arg;
233
234                 if (!line.len)
235                         continue;
236
237                 if (skip_prefix(line.buf, "P ", &arg)) {
238                         /* P name */
239                         if (parse_pack_def(arg, old_cnt++))
240                                 goto out_stale;
241                 } else if (line.buf[0] == 'D') {
242                         /* we used to emit D but that was misguided. */
243                         goto out_stale;
244                 } else if (line.buf[0] == 'T') {
245                         /* we used to emit T but nobody uses it. */
246                         goto out_stale;
247                 } else {
248                         error("unrecognized: %s", line.buf);
249                 }
250         }
251         stale = 0;
252
253  out_stale:
254         strbuf_release(&line);
255         fclose(fp);
256         return stale;
257 }
258
259 static int compare_info(const void *a_, const void *b_)
260 {
261         struct pack_info *const *a = a_;
262         struct pack_info *const *b = b_;
263
264         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
265                 /* Keep the order in the original */
266                 return (*a)->old_num - (*b)->old_num;
267         else if (0 <= (*a)->old_num)
268                 /* Only A existed in the original so B is obviously newer */
269                 return -1;
270         else if (0 <= (*b)->old_num)
271                 /* The other way around. */
272                 return 1;
273
274         /* then it does not matter but at least keep the comparison stable */
275         if ((*a)->p == (*b)->p)
276                 return 0;
277         else if ((*a)->p < (*b)->p)
278                 return -1;
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;
288         size_t alloc = 0;
289
290         for (p = get_all_packs(the_repository); p; p = p->next) {
291                 /* we ignore things on alternate path since they are
292                  * not available to the pullers in general.
293                  */
294                 if (!p->pack_local || !file_exists(p->pack_name))
295                         continue;
296
297                 i = num_pack++;
298                 ALLOC_GROW(info, num_pack, alloc);
299                 info[i] = xcalloc(1, sizeof(struct pack_info));
300                 info[i]->p = p;
301                 info[i]->old_num = -1;
302         }
303
304         if (infofile && !force)
305                 stale = read_pack_info_file(infofile);
306         else
307                 stale = 1;
308
309         for (i = 0; i < num_pack; i++)
310                 if (stale)
311                         info[i]->old_num = -1;
312
313         /* renumber them */
314         QSORT(info, num_pack, compare_info);
315         for (i = 0; i < num_pack; i++)
316                 info[i]->new_num = i;
317 }
318
319 static void free_pack_info(void)
320 {
321         int i;
322         for (i = 0; i < num_pack; i++)
323                 free(info[i]);
324         free(info);
325 }
326
327 static int write_pack_info_file(struct update_info_ctx *uic)
328 {
329         int i;
330         for (i = 0; i < num_pack; i++) {
331                 if (uic_printf(uic, "P %s\n", pack_basename(info[i]->p)) < 0)
332                         return -1;
333         }
334         if (uic_printf(uic, "\n") < 0)
335                 return -1;
336         return 0;
337 }
338
339 static int update_info_packs(int force)
340 {
341         char *infofile = mkpathdup("%s/info/packs", get_object_directory());
342         int ret;
343
344         init_pack_info(infofile, force);
345         ret = update_info_file(infofile, write_pack_info_file, force);
346         free_pack_info();
347         free(infofile);
348         return ret;
349 }
350
351 /* public */
352 int update_server_info(int force)
353 {
354         /* We would add more dumb-server support files later,
355          * including index of available pack files and their
356          * intended audiences.
357          */
358         int errs = 0;
359
360         errs = errs | update_info_refs(force);
361         errs = errs | update_info_packs(force);
362
363         /* remove leftover rev-cache file if there is any */
364         unlink_or_warn(git_path("info/rev-cache"));
365
366         return errs;
367 }