git-fetch-pack: Implement client part of the multi_ack extension
[git.git] / send-pack.c
index 7287c3d..9f9a6e7 100644 (file)
@@ -1,15 +1,26 @@
 #include "cache.h"
+#include "commit.h"
+#include "tag.h"
+#include "refs.h"
 #include "pkt-line.h"
 
-static const char send_pack_usage[] = "git-send-pack [--exec=other] destination [heads]*";
+static const char send_pack_usage[] =
+"git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
+"  --all and explicit <head> specification are mutually exclusive.";
 static const char *exec = "git-receive-pack";
+static int send_all = 0;
+static int force_update = 0;
 
-struct ref {
-       struct ref *next;
-       unsigned char old_sha1[20];
-       unsigned char new_sha1[20];
-       char name[0];
-};
+static int is_zero_sha1(const unsigned char *sha1)
+{
+       int i;
+
+       for (i = 0; i < 20; i++) {
+               if (*sha1++)
+                       return 0;
+       }
+       return 1;
+}
 
 static void exec_pack_objects(void)
 {
@@ -33,11 +44,16 @@ static void exec_rev_list(struct ref *refs)
                char *buf = malloc(100);
                if (i > 900)
                        die("git-rev-list environment overflow");
-               args[i++] = buf;
-               snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
-               buf += 50;
-               args[i++] = buf;
-               snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
+               if (!is_zero_sha1(refs->old_sha1) &&
+                   has_sha1_file(refs->old_sha1)) {
+                       args[i++] = buf;
+                       snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
+                       buf += 50;
+               }
+               if (!is_zero_sha1(refs->new_sha1)) {
+                       args[i++] = buf;
+                       snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
+               }
                refs = refs->next;
        }
        args[i] = NULL;
@@ -89,76 +105,166 @@ static int pack_objects(int fd, struct ref *refs)
        return 0;
 }
 
-static int read_ref(const char *ref, unsigned char *sha1)
+static void unmark_and_free(struct commit_list *list, unsigned int mark)
+{
+       while (list) {
+               struct commit_list *temp = list;
+               temp->item->object.flags &= ~mark;
+               list = temp->next;
+               free(temp);
+       }
+}
+
+static int ref_newer(const unsigned char *new_sha1,
+                    const unsigned char *old_sha1)
 {
-       int fd, ret;
-       char buffer[60];
+       struct object *o;
+       struct commit *old, *new;
+       struct commit_list *list, *used;
+       int found = 0;
 
-       fd = open(git_path("%s", ref), O_RDONLY);
-       if (fd < 0)
-               return -1;
-       ret = -1;
-       if (read(fd, buffer, sizeof(buffer)) >= 40)
-               ret = get_sha1_hex(buffer, sha1);
-       close(fd);
-       return ret;
+       /* Both new and old must be commit-ish and new is descendant of
+        * old.  Otherwise we require --force.
+        */
+       o = deref_tag(parse_object(old_sha1));
+       if (!o || o->type != commit_type)
+               return 0;
+       old = (struct commit *) o;
+
+       o = deref_tag(parse_object(new_sha1));
+       if (!o || o->type != commit_type)
+               return 0;
+       new = (struct commit *) o;
+
+       if (parse_commit(new) < 0)
+               return 0;
+
+       used = list = NULL;
+       commit_list_insert(new, &list);
+       while (list) {
+               new = pop_most_recent_commit(&list, 1);
+               commit_list_insert(new, &used);
+               if (new == old) {
+                       found = 1;
+                       break;
+               }
+       }
+       unmark_and_free(list, 1);
+       unmark_and_free(used, 1);
+       return found;
 }
 
-static int send_pack(int in, int out, int nr_match, char **match)
+static struct ref *local_refs, **local_tail;
+static struct ref *remote_refs, **remote_tail;
+
+static int one_local_ref(const char *refname, const unsigned char *sha1)
 {
-       struct ref *ref_list = NULL, **last_ref = &ref_list;
        struct ref *ref;
+       int len = strlen(refname) + 1;
+       ref = xcalloc(1, sizeof(*ref) + len);
+       memcpy(ref->new_sha1, sha1, 20);
+       memcpy(ref->name, refname, len);
+       *local_tail = ref;
+       local_tail = &ref->next;
+       return 0;
+}
 
-       for (;;) {
-               unsigned char old_sha1[20];
-               unsigned char new_sha1[20];
-               static char buffer[1000];
-               char *name;
-               int len;
+static void get_local_heads(void)
+{
+       local_tail = &local_refs;
+       for_each_ref(one_local_ref);
+}
 
-               len = packet_read_line(in, buffer, sizeof(buffer));
-               if (!len)
-                       break;
-               if (buffer[len-1] == '\n')
-                       buffer[--len] = 0;
+static int send_pack(int in, int out, int nr_refspec, char **refspec)
+{
+       struct ref *ref;
+       int new_refs;
+
+       /* No funny business with the matcher */
+       remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
+       get_local_heads();
 
-               if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
-                       die("protocol error: expected sha/ref, got '%s'", buffer);
-               name = buffer + 41;
-               if (nr_match && !path_match(name, nr_match, match))
+       /* match them up */
+       if (!remote_tail)
+               remote_tail = &remote_refs;
+       if (match_refs(local_refs, remote_refs, &remote_tail,
+                      nr_refspec, refspec, send_all))
+               return -1;
+       /*
+        * Finally, tell the other end!
+        */
+       new_refs = 0;
+       for (ref = remote_refs; ref; ref = ref->next) {
+               char old_hex[60], *new_hex;
+               if (!ref->peer_ref)
                        continue;
-               if (read_ref(name, new_sha1) < 0)
-                       return error("no such local reference '%s'", name);
-               if (!has_sha1_file(old_sha1))
-                       return error("remote '%s' points to object I don't have", name);
-               if (!memcmp(old_sha1, new_sha1, 20)) {
-                       fprintf(stderr, "'%s' unchanged\n", name);
+               if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
+                       fprintf(stderr, "'%s': up-to-date\n", ref->name);
                        continue;
                }
-               ref = xmalloc(sizeof(*ref) + len - 40);
-               memcpy(ref->old_sha1, old_sha1, 20);
-               memcpy(ref->new_sha1, new_sha1, 20);
-               memcpy(ref->name, buffer + 41, len - 40);
-               ref->next = NULL;
-               *last_ref = ref;
-               last_ref = &ref->next;
-       }
 
-       for (ref = ref_list; ref; ref = ref->next) {
-               char old_hex[60], *new_hex;
+               /* This part determines what can overwrite what.
+                * The rules are:
+                *
+                * (0) you can always use --force or +A:B notation to
+                *     selectively force individual ref pairs.
+                *
+                * (1) if the old thing does not exist, it is OK.
+                *
+                * (2) if you do not have the old thing, you are not allowed
+                *     to overwrite it; you would not know what you are losing
+                *     otherwise.
+                *
+                * (3) if both new and old are commit-ish, and new is a
+                *     descendant of old, it is OK.
+                */
+
+               if (!force_update &&
+                   !is_zero_sha1(ref->old_sha1) &&
+                   !ref->force) {
+                       if (!has_sha1_file(ref->old_sha1)) {
+                               error("remote '%s' object %s does not "
+                                     "exist on local",
+                                     ref->name, sha1_to_hex(ref->old_sha1));
+                               continue;
+                       }
+
+                       /* We assume that local is fsck-clean.  Otherwise
+                        * you _could_ have an old tag which points at
+                        * something you do not have, which may or may not
+                        * be a commit.
+                        */
+                       if (!ref_newer(ref->peer_ref->new_sha1,
+                                      ref->old_sha1)) {
+                               error("remote ref '%s' is not a strict "
+                                     "subset of local ref '%s'.", ref->name,
+                                     ref->peer_ref->name);
+                               continue;
+                       }
+               }
+               memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
+               if (is_zero_sha1(ref->new_sha1)) {
+                       error("cannot happen anymore");
+                       continue;
+               }
+               new_refs++;
                strcpy(old_hex, sha1_to_hex(ref->old_sha1));
                new_hex = sha1_to_hex(ref->new_sha1);
                packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
-               fprintf(stderr, "'%s': updating from %s to %s\n", ref->name, old_hex, new_hex);
+               fprintf(stderr, "updating '%s'", ref->name);
+               if (strcmp(ref->name, ref->peer_ref->name))
+                       fprintf(stderr, " using '%s'", ref->peer_ref->name);
+               fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
        }
-       
+
        packet_flush(out);
-       if (ref_list)
-               pack_objects(out, ref_list);
+       if (new_refs)
+               pack_objects(out, remote_refs);
        close(out);
        return 0;
 }
 
+
 int main(int argc, char **argv)
 {
        int i, nr_heads = 0;
@@ -168,23 +274,36 @@ int main(int argc, char **argv)
        pid_t pid;
 
        argv++;
-       for (i = 1; i < argc; i++) {
-               char *arg = *argv++;
+       for (i = 1; i < argc; i++, argv++) {
+               char *arg = *argv;
 
                if (*arg == '-') {
                        if (!strncmp(arg, "--exec=", 7)) {
                                exec = arg + 7;
                                continue;
                        }
+                       if (!strcmp(arg, "--all")) {
+                               send_all = 1;
+                               continue;
+                       }
+                       if (!strcmp(arg, "--force")) {
+                               force_update = 1;
+                               continue;
+                       }
                        usage(send_pack_usage);
                }
-               dest = arg;
+               if (!dest) {
+                       dest = arg;
+                       continue;
+               }
                heads = argv;
-               nr_heads = argc - i -1;
+               nr_heads = argc - i;
                break;
        }
        if (!dest)
                usage(send_pack_usage);
+       if (heads && send_all)
+               usage(send_pack_usage);
        pid = git_connect(fd, dest, exec);
        if (pid < 0)
                return 1;