server-info: simplify cleanup in parse_pack_def()
[git/git.git] / server-info.c
1 #include "cache.h"
2 #include "repository.h"
3 #include "refs.h"
4 #include "object.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "packfile.h"
8 #include "object-store.h"
9
10 /*
11 * Create the file "path" by writing to a temporary file and renaming
12 * it into place. The contents of the file come from "generate", which
13 * should return non-zero if it encounters an error.
14 */
15 static int update_info_file(char *path, int (*generate)(FILE *))
16 {
17 char *tmp = mkpathdup("%s_XXXXXX", path);
18 int ret = -1;
19 int fd = -1;
20 FILE *fp = NULL, *to_close;
21
22 safe_create_leading_directories(path);
23 fd = git_mkstemp_mode(tmp, 0666);
24 if (fd < 0)
25 goto out;
26 to_close = fp = fdopen(fd, "w");
27 if (!fp)
28 goto out;
29 fd = -1;
30 ret = generate(fp);
31 if (ret)
32 goto out;
33 fp = NULL;
34 if (fclose(to_close))
35 goto out;
36 if (adjust_shared_perm(tmp) < 0)
37 goto out;
38 if (rename(tmp, path) < 0)
39 goto out;
40 ret = 0;
41
42 out:
43 if (ret) {
44 error_errno("unable to update %s", path);
45 if (fp)
46 fclose(fp);
47 else if (fd >= 0)
48 close(fd);
49 unlink(tmp);
50 }
51 free(tmp);
52 return ret;
53 }
54
55 static int add_info_ref(const char *path, const struct object_id *oid,
56 int flag, void *cb_data)
57 {
58 FILE *fp = cb_data;
59 struct object *o = parse_object(the_repository, oid);
60 if (!o)
61 return -1;
62
63 if (fprintf(fp, "%s %s\n", oid_to_hex(oid), path) < 0)
64 return -1;
65
66 if (o->type == OBJ_TAG) {
67 o = deref_tag(the_repository, o, path, 0);
68 if (o)
69 if (fprintf(fp, "%s %s^{}\n",
70 oid_to_hex(&o->oid), path) < 0)
71 return -1;
72 }
73 return 0;
74 }
75
76 static int generate_info_refs(FILE *fp)
77 {
78 return for_each_ref(add_info_ref, fp);
79 }
80
81 static int update_info_refs(int force)
82 {
83 char *path = git_pathdup("info/refs");
84 int ret = update_info_file(path, generate_info_refs);
85 free(path);
86 return ret;
87 }
88
89 /* packs */
90 static struct pack_info {
91 struct packed_git *p;
92 int old_num;
93 int new_num;
94 int nr_alloc;
95 } **info;
96 static int num_pack;
97 static const char *objdir;
98 static int objdirlen;
99
100 static struct pack_info *find_pack_by_name(const char *name)
101 {
102 int i;
103 for (i = 0; i < num_pack; i++) {
104 struct packed_git *p = info[i]->p;
105 /* skip "/pack/" after ".git/objects" */
106 if (!strcmp(p->pack_name + objdirlen + 6, name))
107 return info[i];
108 }
109 return NULL;
110 }
111
112 /* Returns non-zero when we detect that the info in the
113 * old file is useless.
114 */
115 static int parse_pack_def(const char *packname, int old_cnt)
116 {
117 struct pack_info *i = find_pack_by_name(packname);
118 if (i) {
119 i->old_num = old_cnt;
120 return 0;
121 }
122 else {
123 /* The file describes a pack that is no longer here */
124 return 1;
125 }
126 }
127
128 /* Returns non-zero when we detect that the info in the
129 * old file is useless.
130 */
131 static int read_pack_info_file(const char *infofile)
132 {
133 FILE *fp;
134 char line[1000];
135 int old_cnt = 0;
136 int stale = 1;
137
138 fp = fopen_or_warn(infofile, "r");
139 if (!fp)
140 return 1; /* nonexistent is not an error. */
141
142 while (fgets(line, sizeof(line), fp)) {
143 const char *arg;
144 int len = strlen(line);
145 if (len && line[len-1] == '\n')
146 line[--len] = 0;
147
148 if (!len)
149 continue;
150
151 if (skip_prefix(line, "P ", &arg)) {
152 /* P name */
153 if (parse_pack_def(arg, old_cnt++))
154 goto out_stale;
155 } else if (line[0] == 'D') {
156 /* we used to emit D but that was misguided. */
157 goto out_stale;
158 } else if (line[0] == 'T') {
159 /* we used to emit T but nobody uses it. */
160 goto out_stale;
161 } else {
162 error("unrecognized: %s", line);
163 }
164 }
165 stale = 0;
166
167 out_stale:
168 fclose(fp);
169 return stale;
170 }
171
172 static int compare_info(const void *a_, const void *b_)
173 {
174 struct pack_info *const *a = a_;
175 struct pack_info *const *b = b_;
176
177 if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
178 /* Keep the order in the original */
179 return (*a)->old_num - (*b)->old_num;
180 else if (0 <= (*a)->old_num)
181 /* Only A existed in the original so B is obviously newer */
182 return -1;
183 else if (0 <= (*b)->old_num)
184 /* The other way around. */
185 return 1;
186
187 /* then it does not matter but at least keep the comparison stable */
188 if ((*a)->p == (*b)->p)
189 return 0;
190 else if ((*a)->p < (*b)->p)
191 return -1;
192 else
193 return 1;
194 }
195
196 static void init_pack_info(const char *infofile, int force)
197 {
198 struct packed_git *p;
199 int stale;
200 int i = 0;
201
202 objdir = get_object_directory();
203 objdirlen = strlen(objdir);
204
205 for (p = get_all_packs(the_repository); p; p = p->next) {
206 /* we ignore things on alternate path since they are
207 * not available to the pullers in general.
208 */
209 if (!p->pack_local)
210 continue;
211 i++;
212 }
213 num_pack = i;
214 info = xcalloc(num_pack, sizeof(struct pack_info *));
215 for (i = 0, p = get_all_packs(the_repository); p; p = p->next) {
216 if (!p->pack_local)
217 continue;
218 info[i] = xcalloc(1, sizeof(struct pack_info));
219 info[i]->p = p;
220 info[i]->old_num = -1;
221 i++;
222 }
223
224 if (infofile && !force)
225 stale = read_pack_info_file(infofile);
226 else
227 stale = 1;
228
229 for (i = 0; i < num_pack; i++)
230 if (stale)
231 info[i]->old_num = -1;
232
233 /* renumber them */
234 QSORT(info, num_pack, compare_info);
235 for (i = 0; i < num_pack; i++)
236 info[i]->new_num = i;
237 }
238
239 static void free_pack_info(void)
240 {
241 int i;
242 for (i = 0; i < num_pack; i++)
243 free(info[i]);
244 free(info);
245 }
246
247 static int write_pack_info_file(FILE *fp)
248 {
249 int i;
250 for (i = 0; i < num_pack; i++) {
251 if (fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6) < 0)
252 return -1;
253 }
254 if (fputc('\n', fp) == EOF)
255 return -1;
256 return 0;
257 }
258
259 static int update_info_packs(int force)
260 {
261 char *infofile = mkpathdup("%s/info/packs", get_object_directory());
262 int ret;
263
264 init_pack_info(infofile, force);
265 ret = update_info_file(infofile, write_pack_info_file);
266 free_pack_info();
267 free(infofile);
268 return ret;
269 }
270
271 /* public */
272 int update_server_info(int force)
273 {
274 /* We would add more dumb-server support files later,
275 * including index of available pack files and their
276 * intended audiences.
277 */
278 int errs = 0;
279
280 errs = errs | update_info_refs(force);
281 errs = errs | update_info_packs(force);
282
283 /* remove leftover rev-cache file if there is any */
284 unlink_or_warn(git_path("info/rev-cache"));
285
286 return errs;
287 }