Add a "git-describe" command
[git.git] / clone-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4
5 static const char clone_pack_usage[] =
6 "git-clone-pack [--exec=<git-upload-pack>] [<host>:]<directory> [<heads>]*";
7 static const char *exec = "git-upload-pack";
8
9 static void clone_handshake(int fd[2], struct ref *ref)
10 {
11         unsigned char sha1[20];
12
13         while (ref) {
14                 packet_write(fd[1], "want %s\n", sha1_to_hex(ref->old_sha1));
15                 ref = ref->next;
16         }
17         packet_flush(fd[1]);
18
19         /* We don't have nuttin' */
20         packet_write(fd[1], "done\n");
21         if (get_ack(fd[0], sha1))
22                 error("Huh! git-clone-pack got positive ack for %s", sha1_to_hex(sha1));
23 }
24
25 static int is_master(struct ref *ref)
26 {
27         return !strcmp(ref->name, "refs/heads/master");
28 }
29
30 static void write_one_ref(struct ref *ref)
31 {
32         char *path = git_path("%s", ref->name);
33         int fd;
34         char *hex;
35
36         if (!strncmp(ref->name, "refs/", 5) &&
37             check_ref_format(ref->name + 5)) {
38                 error("refusing to create funny ref '%s' locally", ref->name);
39                 return;
40         }
41
42         if (safe_create_leading_directories(path))
43                 die("unable to create leading directory for %s", ref->name);
44         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
45         if (fd < 0)
46                 die("unable to create ref %s", ref->name);
47         hex = sha1_to_hex(ref->old_sha1);
48         hex[40] = '\n';
49         if (write(fd, hex, 41) != 41)
50                 die("unable to write ref %s", ref->name);
51         close(fd);
52 }
53
54 static void write_refs(struct ref *ref)
55 {
56         struct ref *head = NULL, *head_ptr, *master_ref;
57         char *head_path;
58
59         /* Upload-pack must report HEAD first */
60         if (!strcmp(ref->name, "HEAD")) {
61                 head = ref;
62                 ref = ref->next;
63         }
64         head_ptr = NULL;
65         master_ref = NULL;
66         while (ref) {
67                 if (is_master(ref))
68                         master_ref = ref;
69                 if (head &&
70                     !memcmp(ref->old_sha1, head->old_sha1, 20) &&
71                     !strncmp(ref->name, "refs/heads/",11) &&
72                     (!head_ptr || ref == master_ref))
73                         head_ptr = ref;
74
75                 write_one_ref(ref);
76                 ref = ref->next;
77         }
78         if (!head) {
79                 fprintf(stderr, "No HEAD in remote.\n");
80                 return;
81         }
82
83         head_path = strdup(git_path("HEAD"));
84         if (!head_ptr) {
85                 /*
86                  * If we had a master ref, and it wasn't HEAD, we need to undo the
87                  * symlink, and write a standalone HEAD. Give a warning, because that's
88                  * really really wrong.
89                  */
90                 if (master_ref) {
91                         error("HEAD doesn't point to any refs! Making standalone HEAD");
92                         unlink(head_path);
93                 }
94                 write_one_ref(head);
95                 free(head_path);
96                 return;
97         }
98
99         /* We reset to the master branch if it's available */
100         if (master_ref)
101                 return;
102
103         fprintf(stderr, "Setting HEAD to %s\n", head_ptr->name);
104
105         /*
106          * Uhhuh. Other end didn't have master. We start HEAD off with
107          * the first branch with the same value.
108          */
109         if (create_symref(head_path, head_ptr->name) < 0)
110                 die("unable to link HEAD to %s", head_ptr->name);
111         free(head_path);
112 }
113
114 static int clone_pack(int fd[2], int nr_match, char **match)
115 {
116         struct ref *refs;
117         int status;
118
119         get_remote_heads(fd[0], &refs, nr_match, match, 1);
120         if (!refs) {
121                 packet_flush(fd[1]);
122                 die("no matching remote head");
123         }
124         clone_handshake(fd, refs);
125
126         status = receive_keep_pack(fd, "git-clone-pack");
127
128         if (!status) {
129                 if (nr_match == 0)
130                         write_refs(refs);
131                 else
132                         while (refs) {
133                                 printf("%s %s\n",
134                                        sha1_to_hex(refs->old_sha1),
135                                        refs->name);
136                                 refs = refs->next;
137                         }
138         }
139         return status;
140 }
141
142 int main(int argc, char **argv)
143 {
144         int i, ret, nr_heads;
145         char *dest = NULL, **heads;
146         int fd[2];
147         pid_t pid;
148
149         setup_git_directory();
150
151         nr_heads = 0;
152         heads = NULL;
153         for (i = 1; i < argc; i++) {
154                 char *arg = argv[i];
155
156                 if (*arg == '-') {
157                         if (!strcmp("-q", arg))
158                                 continue;
159                         if (!strncmp("--exec=", arg, 7)) {
160                                 exec = arg + 7;
161                                 continue;
162                         }
163                         usage(clone_pack_usage);
164                 }
165                 dest = arg;
166                 heads = argv + i + 1;
167                 nr_heads = argc - i - 1;
168                 break;
169         }
170         if (!dest)
171                 usage(clone_pack_usage);
172         pid = git_connect(fd, dest, exec);
173         if (pid < 0)
174                 return 1;
175         ret = clone_pack(fd, nr_heads, heads);
176         close(fd[0]);
177         close(fd[1]);
178         finish_connect(pid);
179         return ret;
180 }