Fix ref_newer() in send-pack.
[git] / send-pack.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "refs.h"
5 #include "pkt-line.h"
6
7 static const char send_pack_usage[] =
8 "git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
9 "  --all and explicit <head> specification are mutually exclusive.";
10 static const char *exec = "git-receive-pack";
11 static int send_all = 0;
12 static int force_update = 0;
13
14 static int is_zero_sha1(const unsigned char *sha1)
15 {
16         int i;
17
18         for (i = 0; i < 20; i++) {
19                 if (*sha1++)
20                         return 0;
21         }
22         return 1;
23 }
24
25 static void exec_pack_objects(void)
26 {
27         static char *args[] = {
28                 "git-pack-objects",
29                 "--stdout",
30                 NULL
31         };
32         execvp("git-pack-objects", args);
33         die("git-pack-objects exec failed (%s)", strerror(errno));
34 }
35
36 static void exec_rev_list(struct ref *refs)
37 {
38         static char *args[1000];
39         int i = 0;
40
41         args[i++] = "git-rev-list";     /* 0 */
42         args[i++] = "--objects";        /* 1 */
43         while (refs) {
44                 char *buf = malloc(100);
45                 if (i > 900)
46                         die("git-rev-list environment overflow");
47                 if (!is_zero_sha1(refs->old_sha1) &&
48                     has_sha1_file(refs->old_sha1)) {
49                         args[i++] = buf;
50                         snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
51                         buf += 50;
52                 }
53                 if (!is_zero_sha1(refs->new_sha1)) {
54                         args[i++] = buf;
55                         snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
56                 }
57                 refs = refs->next;
58         }
59         args[i] = NULL;
60         execvp("git-rev-list", args);
61         die("git-rev-list exec failed (%s)", strerror(errno));
62 }
63
64 static void rev_list(int fd, struct ref *refs)
65 {
66         int pipe_fd[2];
67         pid_t pack_objects_pid;
68
69         if (pipe(pipe_fd) < 0)
70                 die("rev-list setup: pipe failed");
71         pack_objects_pid = fork();
72         if (!pack_objects_pid) {
73                 dup2(pipe_fd[0], 0);
74                 dup2(fd, 1);
75                 close(pipe_fd[0]);
76                 close(pipe_fd[1]);
77                 close(fd);
78                 exec_pack_objects();
79                 die("pack-objects setup failed");
80         }
81         if (pack_objects_pid < 0)
82                 die("pack-objects fork failed");
83         dup2(pipe_fd[1], 1);
84         close(pipe_fd[0]);
85         close(pipe_fd[1]);
86         close(fd);
87         exec_rev_list(refs);
88 }
89
90 static int pack_objects(int fd, struct ref *refs)
91 {
92         pid_t rev_list_pid;
93
94         rev_list_pid = fork();
95         if (!rev_list_pid) {
96                 rev_list(fd, refs);
97                 die("rev-list setup failed");
98         }
99         if (rev_list_pid < 0)
100                 die("rev-list fork failed");
101         /*
102          * We don't wait for the rev-list pipeline in the parent:
103          * we end up waiting for the other end instead
104          */
105         return 0;
106 }
107
108 static void unmark_and_free(struct commit_list *list, unsigned int mark)
109 {
110         while (list) {
111                 struct commit_list *temp = list;
112                 temp->item->object.flags &= ~mark;
113                 list = temp->next;
114                 free(temp);
115         }
116 }
117
118 static int ref_newer(const unsigned char *new_sha1,
119                      const unsigned char *old_sha1)
120 {
121         struct object *o;
122         struct commit *old, *new;
123         struct commit_list *list, *used;
124         int found = 0;
125
126         /* Both new and old must be commit-ish and new is descendant of
127          * old.  Otherwise we require --force.
128          */
129         o = deref_tag(parse_object(old_sha1));
130         if (!o || o->type != commit_type)
131                 return 0;
132         old = (struct commit *) o;
133
134         o = deref_tag(parse_object(new_sha1));
135         if (!o || o->type != commit_type)
136                 return 0;
137         new = (struct commit *) o;
138
139         if (parse_commit(new) < 0)
140                 return 0;
141
142         used = list = NULL;
143         commit_list_insert(new, &list);
144         while (list) {
145                 new = pop_most_recent_commit(&list, 1);
146                 commit_list_insert(new, &used);
147                 if (new == old) {
148                         found = 1;
149                         break;
150                 }
151         }
152         unmark_and_free(list, 1);
153         unmark_and_free(used, 1);
154         return found;
155 }
156
157 static struct ref *local_refs, **local_tail;
158 static struct ref *remote_refs, **remote_tail;
159
160 static int one_local_ref(const char *refname, const unsigned char *sha1)
161 {
162         struct ref *ref;
163         int len = strlen(refname) + 1;
164         ref = xcalloc(1, sizeof(*ref) + len);
165         memcpy(ref->new_sha1, sha1, 20);
166         memcpy(ref->name, refname, len);
167         *local_tail = ref;
168         local_tail = &ref->next;
169         return 0;
170 }
171
172 static void get_local_heads(void)
173 {
174         local_tail = &local_refs;
175         for_each_ref(one_local_ref);
176 }
177
178 static int send_pack(int in, int out, int nr_refspec, char **refspec)
179 {
180         struct ref *ref;
181         int new_refs;
182
183         /* No funny business with the matcher */
184         remote_tail = get_remote_heads(in, &remote_refs, 0, NULL);
185         get_local_heads();
186
187         /* match them up */
188         if (!remote_tail)
189                 remote_tail = &remote_refs;
190         if (match_refs(local_refs, remote_refs, &remote_tail,
191                        nr_refspec, refspec, send_all))
192                 return -1;
193         /*
194          * Finally, tell the other end!
195          */
196         new_refs = 0;
197         for (ref = remote_refs; ref; ref = ref->next) {
198                 char old_hex[60], *new_hex;
199                 if (!ref->peer_ref)
200                         continue;
201                 if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
202                         fprintf(stderr, "'%s': up-to-date\n", ref->name);
203                         continue;
204                 }
205
206                 /* This part determines what can overwrite what.
207                  * The rules are:
208                  *
209                  * (0) you can always use --force.
210                  *
211                  * (1) if the old thing does not exist, it is OK.
212                  *
213                  * (2) if you do not have the old thing, you are not allowed
214                  *     to overwrite it; you would not know what you are losing
215                  *     otherwise.
216                  *
217                  * (3) if both new and old are commit-ish, and new is a
218                  *     descendant of old, it is OK.
219                  */
220
221                 if (!force_update && !is_zero_sha1(ref->old_sha1)) {
222                         if (!has_sha1_file(ref->old_sha1)) {
223                                 error("remote '%s' object %s does not "
224                                       "exist on local",
225                                       ref->name, sha1_to_hex(ref->old_sha1));
226                                 continue;
227                         }
228                         /* We assume that local is fsck-clean.  Otherwise
229                          * you _could_ have a old tag which points at
230                          * something you do not have which may or may not
231                          * be a commit.
232                          */
233                         if (!ref_newer(ref->peer_ref->new_sha1,
234                                        ref->old_sha1)) {
235                                 error("remote ref '%s' is not a strict "
236                                       "subset of local ref '%s'.", ref->name,
237                                       ref->peer_ref->name);
238                                 continue;
239                         }
240                 }
241                 memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
242                 if (is_zero_sha1(ref->new_sha1)) {
243                         error("cannot happen anymore");
244                         continue;
245                 }
246                 new_refs++;
247                 strcpy(old_hex, sha1_to_hex(ref->old_sha1));
248                 new_hex = sha1_to_hex(ref->new_sha1);
249                 packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
250                 fprintf(stderr, "updating '%s'", ref->name);
251                 if (strcmp(ref->name, ref->peer_ref->name))
252                         fprintf(stderr, " using '%s'", ref->peer_ref->name);
253                 fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
254         }
255
256         packet_flush(out);
257         if (new_refs)
258                 pack_objects(out, remote_refs);
259         close(out);
260         return 0;
261 }
262
263
264 int main(int argc, char **argv)
265 {
266         int i, nr_heads = 0;
267         char *dest = NULL;
268         char **heads = NULL;
269         int fd[2], ret;
270         pid_t pid;
271
272         argv++;
273         for (i = 1; i < argc; i++, argv++) {
274                 char *arg = *argv;
275
276                 if (*arg == '-') {
277                         if (!strncmp(arg, "--exec=", 7)) {
278                                 exec = arg + 7;
279                                 continue;
280                         }
281                         if (!strcmp(arg, "--all")) {
282                                 send_all = 1;
283                                 continue;
284                         }
285                         if (!strcmp(arg, "--force")) {
286                                 force_update = 1;
287                                 continue;
288                         }
289                         usage(send_pack_usage);
290                 }
291                 if (!dest) {
292                         dest = arg;
293                         continue;
294                 }
295                 heads = argv;
296                 nr_heads = argc - i;
297                 break;
298         }
299         if (!dest)
300                 usage(send_pack_usage);
301         if (heads && send_all)
302                 usage(send_pack_usage);
303         pid = git_connect(fd, dest, exec);
304         if (pid < 0)
305                 return 1;
306         ret = send_pack(fd[0], fd[1], nr_heads, heads);
307         close(fd[0]);
308         close(fd[1]);
309         finish_connect(pid);
310         return ret;
311 }