Add a "git-describe" command
[git.git] / upload-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include "tag.h"
5 #include "object.h"
6 #include "commit.h"
7
8 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
9
10 #define THEY_HAVE (1U << 0)
11 #define OUR_REF (1U << 1)
12 #define WANTED (1U << 2)
13 #define MAX_HAS 256
14 #define MAX_NEEDS 256
15 static int nr_has = 0, nr_needs = 0, multi_ack = 0, nr_our_refs = 0;
16 static unsigned char has_sha1[MAX_HAS][20];
17 static unsigned char needs_sha1[MAX_NEEDS][20];
18 static unsigned int timeout = 0;
19
20 static void reset_timeout(void)
21 {
22         alarm(timeout);
23 }
24
25 static int strip(char *line, int len)
26 {
27         if (len && line[len-1] == '\n')
28                 line[--len] = 0;
29         return len;
30 }
31
32 static void create_pack_file(void)
33 {
34         int fd[2];
35         pid_t pid;
36         int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
37
38         if (pipe(fd) < 0)
39                 die("git-upload-pack: unable to create pipe");
40         pid = fork();
41         if (pid < 0)
42                 die("git-upload-pack: unable to fork git-rev-list");
43
44         if (!pid) {
45                 int i;
46                 int args;
47                 char **argv;
48                 char *buf;
49                 char **p;
50
51                 if (create_full_pack)
52                         args = 10;
53                 else
54                         args = nr_has + nr_needs + 5;
55                 argv = xmalloc(args * sizeof(char *));
56                 buf = xmalloc(args * 45);
57                 p = argv;
58
59                 dup2(fd[1], 1);
60                 close(0);
61                 close(fd[0]);
62                 close(fd[1]);
63                 *p++ = "git-rev-list";
64                 *p++ = "--objects";
65                 if (create_full_pack || MAX_NEEDS <= nr_needs)
66                         *p++ = "--all";
67                 else {
68                         for (i = 0; i < nr_needs; i++) {
69                                 *p++ = buf;
70                                 memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
71                                 buf += 41;
72                         }
73                 }
74                 if (!create_full_pack)
75                         for (i = 0; i < nr_has; i++) {
76                                 *p++ = buf;
77                                 *buf++ = '^';
78                                 memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
79                                 buf += 41;
80                         }
81                 *p++ = NULL;
82                 execvp("git-rev-list", argv);
83                 die("git-upload-pack: unable to exec git-rev-list");
84         }
85         dup2(fd[0], 0);
86         close(fd[0]);
87         close(fd[1]);
88         execlp("git-pack-objects", "git-pack-objects", "--stdout", NULL);
89         die("git-upload-pack: unable to exec git-pack-objects");
90 }
91
92 static int got_sha1(char *hex, unsigned char *sha1)
93 {
94         if (get_sha1_hex(hex, sha1))
95                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
96         if (!has_sha1_file(sha1))
97                 return 0;
98         if (nr_has < MAX_HAS) {
99                 struct object *o = lookup_object(sha1);
100                 if (!(o && o->parsed))
101                         o = parse_object(sha1);
102                 if (!o)
103                         die("oops (%s)", sha1_to_hex(sha1));
104                 if (o->type == commit_type) {
105                         struct commit_list *parents;
106                         if (o->flags & THEY_HAVE)
107                                 return 0;
108                         o->flags |= THEY_HAVE;
109                         for (parents = ((struct commit*)o)->parents;
110                              parents;
111                              parents = parents->next)
112                                 parents->item->object.flags |= THEY_HAVE;
113                 }
114                 memcpy(has_sha1[nr_has++], sha1, 20);
115         }
116         return 1;
117 }
118
119 static int get_common_commits(void)
120 {
121         static char line[1000];
122         unsigned char sha1[20], last_sha1[20];
123         int len;
124
125         track_object_refs = 0;
126         save_commit_buffer = 0;
127
128         for(;;) {
129                 len = packet_read_line(0, line, sizeof(line));
130                 reset_timeout();
131
132                 if (!len) {
133                         if (nr_has == 0 || multi_ack)
134                                 packet_write(1, "NAK\n");
135                         continue;
136                 }
137                 len = strip(line, len);
138                 if (!strncmp(line, "have ", 5)) {
139                         if (got_sha1(line+5, sha1) &&
140                                         (multi_ack || nr_has == 1)) {
141                                 if (nr_has >= MAX_HAS)
142                                         multi_ack = 0;
143                                 packet_write(1, "ACK %s%s\n",
144                                         sha1_to_hex(sha1),
145                                         multi_ack ?  " continue" : "");
146                                 if (multi_ack)
147                                         memcpy(last_sha1, sha1, 20);
148                         }
149                         continue;
150                 }
151                 if (!strcmp(line, "done")) {
152                         if (nr_has > 0) {
153                                 if (multi_ack)
154                                         packet_write(1, "ACK %s\n",
155                                                         sha1_to_hex(last_sha1));
156                                 return 0;
157                         }
158                         packet_write(1, "NAK\n");
159                         return -1;
160                 }
161                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
162         }
163 }
164
165 static int receive_needs(void)
166 {
167         static char line[1000];
168         int len, needs;
169
170         needs = 0;
171         for (;;) {
172                 struct object *o;
173                 unsigned char dummy[20], *sha1_buf;
174                 len = packet_read_line(0, line, sizeof(line));
175                 reset_timeout();
176                 if (!len)
177                         return needs;
178
179                 sha1_buf = dummy;
180                 if (needs == MAX_NEEDS) {
181                         fprintf(stderr,
182                                 "warning: supporting only a max of %d requests. "
183                                 "sending everything instead.\n",
184                                 MAX_NEEDS);
185                 }
186                 else if (needs < MAX_NEEDS)
187                         sha1_buf = needs_sha1[needs];
188
189                 if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
190                         die("git-upload-pack: protocol error, "
191                             "expected to get sha, not '%s'", line);
192                 if (strstr(line+45, "multi_ack"))
193                         multi_ack = 1;
194
195                 /* We have sent all our refs already, and the other end
196                  * should have chosen out of them; otherwise they are
197                  * asking for nonsense.
198                  *
199                  * Hmph.  We may later want to allow "want" line that
200                  * asks for something like "master~10" (symbolic)...
201                  * would it make sense?  I don't know.
202                  */
203                 o = lookup_object(sha1_buf);
204                 if (!o || !(o->flags & OUR_REF))
205                         die("git-upload-pack: not our ref %s", line+5);
206                 if (!(o->flags & WANTED)) {
207                         o->flags |= WANTED;
208                         needs++;
209                 }
210         }
211 }
212
213 static int send_ref(const char *refname, const unsigned char *sha1)
214 {
215         static char *capabilities = "multi_ack";
216         struct object *o = parse_object(sha1);
217
218         if (capabilities)
219                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
220                         0, capabilities);
221         else
222                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
223         capabilities = NULL;
224         if (!(o->flags & OUR_REF)) {
225                 o->flags |= OUR_REF;
226                 nr_our_refs++;
227         }
228         if (o->type == tag_type) {
229                 o = deref_tag(o, refname, 0);
230                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
231         }
232         return 0;
233 }
234
235 static int upload_pack(void)
236 {
237         reset_timeout();
238         head_ref(send_ref);
239         for_each_ref(send_ref);
240         packet_flush(1);
241         nr_needs = receive_needs();
242         if (!nr_needs)
243                 return 0;
244         get_common_commits();
245         create_pack_file();
246         return 0;
247 }
248
249 int main(int argc, char **argv)
250 {
251         char *dir;
252         int i;
253         int strict = 0;
254
255         for (i = 1; i < argc; i++) {
256                 char *arg = argv[i];
257
258                 if (arg[0] != '-')
259                         break;
260                 if (!strcmp(arg, "--strict")) {
261                         strict = 1;
262                         continue;
263                 }
264                 if (!strncmp(arg, "--timeout=", 10)) {
265                         timeout = atoi(arg+10);
266                         continue;
267                 }
268                 if (!strcmp(arg, "--")) {
269                         i++;
270                         break;
271                 }
272         }
273         
274         if (i != argc-1)
275                 usage(upload_pack_usage);
276         dir = argv[i];
277
278         if (!enter_repo(dir, strict))
279                 die("'%s': unable to chdir or not a git archive", dir);
280
281         upload_pack();
282         return 0;
283 }