improve diff-delta with sparse and/or repetitive data
[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 int quiet = 0;
10
11 static void clone_handshake(int fd[2], struct ref *ref)
12 {
13         unsigned char sha1[20];
14
15         while (ref) {
16                 packet_write(fd[1], "want %s\n", sha1_to_hex(ref->old_sha1));
17                 ref = ref->next;
18         }
19         packet_flush(fd[1]);
20
21         /* We don't have nuttin' */
22         packet_write(fd[1], "done\n");
23         if (get_ack(fd[0], sha1))
24                 error("Huh! git-clone-pack got positive ack for %s", sha1_to_hex(sha1));
25 }
26
27 static int is_master(struct ref *ref)
28 {
29         return !strcmp(ref->name, "refs/heads/master");
30 }
31
32 static void write_one_ref(struct ref *ref)
33 {
34         char *path = git_path("%s", ref->name);
35         int fd;
36         char *hex;
37
38         if (!strncmp(ref->name, "refs/", 5) &&
39             check_ref_format(ref->name + 5)) {
40                 error("refusing to create funny ref '%s' locally", ref->name);
41                 return;
42         }
43
44         if (safe_create_leading_directories(path))
45                 die("unable to create leading directory for %s", ref->name);
46         fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
47         if (fd < 0)
48                 die("unable to create ref %s", ref->name);
49         hex = sha1_to_hex(ref->old_sha1);
50         hex[40] = '\n';
51         if (write(fd, hex, 41) != 41)
52                 die("unable to write ref %s", ref->name);
53         close(fd);
54 }
55
56 static void write_refs(struct ref *ref)
57 {
58         struct ref *head = NULL, *head_ptr, *master_ref;
59         char *head_path;
60
61         /* Upload-pack must report HEAD first */
62         if (!strcmp(ref->name, "HEAD")) {
63                 head = ref;
64                 ref = ref->next;
65         }
66         head_ptr = NULL;
67         master_ref = NULL;
68         while (ref) {
69                 if (is_master(ref))
70                         master_ref = ref;
71                 if (head &&
72                     !memcmp(ref->old_sha1, head->old_sha1, 20) &&
73                     !strncmp(ref->name, "refs/heads/",11) &&
74                     (!head_ptr || ref == master_ref))
75                         head_ptr = ref;
76
77                 write_one_ref(ref);
78                 ref = ref->next;
79         }
80         if (!head) {
81                 fprintf(stderr, "No HEAD in remote.\n");
82                 return;
83         }
84
85         head_path = strdup(git_path("HEAD"));
86         if (!head_ptr) {
87                 /*
88                  * If we had a master ref, and it wasn't HEAD, we need to undo the
89                  * symlink, and write a standalone HEAD. Give a warning, because that's
90                  * really really wrong.
91                  */
92                 if (master_ref) {
93                         error("HEAD doesn't point to any refs! Making standalone HEAD");
94                         unlink(head_path);
95                 }
96                 write_one_ref(head);
97                 free(head_path);
98                 return;
99         }
100
101         /* We reset to the master branch if it's available */
102         if (master_ref)
103                 return;
104
105         fprintf(stderr, "Setting HEAD to %s\n", head_ptr->name);
106
107         /*
108          * Uhhuh. Other end didn't have master. We start HEAD off with
109          * the first branch with the same value.
110          */
111         if (create_symref(head_path, head_ptr->name) < 0)
112                 die("unable to link HEAD to %s", head_ptr->name);
113         free(head_path);
114 }
115
116 static int clone_pack(int fd[2], int nr_match, char **match)
117 {
118         struct ref *refs;
119         int status;
120
121         get_remote_heads(fd[0], &refs, nr_match, match, 1);
122         if (!refs) {
123                 packet_flush(fd[1]);
124                 die("no matching remote head");
125         }
126         clone_handshake(fd, refs);
127
128         status = receive_keep_pack(fd, "git-clone-pack", quiet);
129         if (!quiet)
130                 fprintf(stderr, "\n");
131
132         if (!status) {
133                 if (nr_match == 0)
134                         write_refs(refs);
135                 else
136                         while (refs) {
137                                 printf("%s %s\n",
138                                        sha1_to_hex(refs->old_sha1),
139                                        refs->name);
140                                 refs = refs->next;
141                         }
142         }
143         return status;
144 }
145
146 int main(int argc, char **argv)
147 {
148         int i, ret, nr_heads;
149         char *dest = NULL, **heads;
150         int fd[2];
151         pid_t pid;
152
153         setup_git_directory();
154
155         nr_heads = 0;
156         heads = NULL;
157         for (i = 1; i < argc; i++) {
158                 char *arg = argv[i];
159
160                 if (*arg == '-') {
161                         if (!strcmp("-q", arg)) {
162                                 quiet = 1;
163                                 continue;
164                         }
165                         if (!strncmp("--exec=", arg, 7)) {
166                                 exec = arg + 7;
167                                 continue;
168                         }
169                         usage(clone_pack_usage);
170                 }
171                 dest = arg;
172                 heads = argv + i + 1;
173                 nr_heads = argc - i - 1;
174                 break;
175         }
176         if (!dest)
177                 usage(clone_pack_usage);
178         pid = git_connect(fd, dest, exec);
179         if (pid < 0)
180                 return 1;
181         ret = clone_pack(fd, nr_heads, heads);
182         close(fd[0]);
183         close(fd[1]);
184         finish_connect(pid);
185         return ret;
186 }