Make maximal use of the remote refs
[gitweb.git] / fetch-pack.c
index 65e007639ac744c3f354f71c157a85c5d6477d49..b58426431f334c972ec9b508d3217fea65af0ab0 100644 (file)
 #include "cache.h"
 #include "refs.h"
 #include "pkt-line.h"
+#include "commit.h"
+#include "tag.h"
+#include <time.h>
 #include <sys/wait.h>
 
 static int quiet;
-static const char fetch_pack_usage[] = "git-fetch-pack [-q] [--exec=upload-pack] [host:]directory [heads]* < mycommitlist";
+static int verbose;
+static const char fetch_pack_usage[] =
+"git-fetch-pack [-q] [-v] [--exec=upload-pack] [host:]directory <refs>...";
 static const char *exec = "git-upload-pack";
 
-static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
+#define COMPLETE       (1U << 0)
+#define COMMON         (1U << 1)
+#define COMMON_REF     (1U << 2)
+#define SEEN           (1U << 3)
+#define POPPED         (1U << 4)
+
+static struct commit_list *rev_list = NULL;
+static int non_common_revs = 0;
+
+static void rev_list_push(struct commit *commit, int mark)
+{
+       if (!(commit->object.flags & mark)) {
+               commit->object.flags |= mark;
+
+               if (!(commit->object.parsed))
+                       parse_commit(commit);
+
+               insert_by_date(commit, &rev_list);
+
+               if (!(commit->object.flags & COMMON))
+                       non_common_revs++;
+       }
+}
+
+static int rev_list_insert_ref(const char *path, const unsigned char *sha1)
+{
+       struct object *o = deref_tag(parse_object(sha1));
+
+       if (o->type == commit_type)
+               rev_list_push((struct commit *)o, SEEN);
+
+       return 0;
+}
+
+/*
+   This function marks a rev and its ancestors as common.
+   In some cases, it is desirable to mark only the ancestors (for example
+   when only the server does not yet know that they are common).
+*/
+
+static void mark_common(struct commit *commit,
+               int ancestors_only, int dont_parse)
+{
+       if (commit != NULL && !(commit->object.flags & COMMON)) {
+               struct object *o = (struct object *)commit;
+
+               if (!ancestors_only)
+                       o->flags |= COMMON;
+
+               if (!(o->flags & SEEN))
+                       rev_list_push(commit, SEEN);
+               else {
+                       struct commit_list *parents;
+
+                       if (!ancestors_only && !(o->flags & POPPED))
+                               non_common_revs--;
+                       if (!o->parsed && !dont_parse)
+                               parse_commit(commit);
+
+                       for (parents = commit->parents;
+                                       parents;
+                                       parents = parents->next)
+                               mark_common(parents->item, 0, dont_parse);
+               }
+       }
+}
+
+/*
+  Get the next rev to send, ignoring the common.
+*/
+
+static const unsigned char* get_rev()
+{
+       struct commit *commit = NULL;
+
+       while (commit == NULL) {
+               unsigned int mark;
+               struct commit_list* parents;
+
+               if (rev_list == NULL || non_common_revs == 0)
+                       return NULL;
+
+               commit = rev_list->item;
+               if (!(commit->object.parsed))
+                       parse_commit(commit);
+               commit->object.flags |= POPPED;
+               if (!(commit->object.flags & COMMON))
+                       non_common_revs--;
+       
+               parents = commit->parents;
+
+               if (commit->object.flags & COMMON) {
+                       /* do not send "have", and ignore ancestors */
+                       commit = NULL;
+                       mark = COMMON | SEEN;
+               } else if (commit->object.flags & COMMON_REF)
+                       /* send "have", and ignore ancestors */
+                       mark = COMMON | SEEN;
+               else
+                       /* send "have", also for its ancestors */
+                       mark = SEEN;
+
+               while (parents) {
+                       if (!(parents->item->object.flags & SEEN))
+                               rev_list_push(parents->item, mark);
+                       if (mark & COMMON)
+                               mark_common(parents->item, 1, 0);
+                       parents = parents->next;
+               }
+
+               rev_list = rev_list->next;
+       }
+
+       return commit->object.sha1;
+}
+
+static int find_common(int fd[2], unsigned char *result_sha1,
+                      struct ref *refs)
 {
-       static char line[1000];
+       int fetching;
        int count = 0, flushes = 0, retval;
-       FILE *revs;
+       const unsigned char *sha1;
+
+       for_each_ref(rev_list_insert_ref);
+
+       fetching = 0;
+       for ( ; refs ; refs = refs->next) {
+               unsigned char *remote = refs->old_sha1;
+               struct object *o;
+
+               /*
+                * If that object is complete (i.e. it is an ancestor of a
+                * local ref), we tell them we have it but do not have to
+                * tell them about its ancestors, which they already know
+                * about.
+                *
+                * We use lookup_object here because we are only
+                * interested in the case we *know* the object is
+                * reachable and we have already scanned it.
+                */
+               if (((o = lookup_object(remote)) != NULL) &&
+                               (o->flags & COMPLETE)) {
+                       continue;
+               }
 
-       revs = popen("git-rev-list $(git-rev-parse --all)", "r");
-       if (!revs)
-               die("unable to run 'git-rev-list'");
-       packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+               packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+               fetching++;
+       }
        packet_flush(fd[1]);
-       flushes = 1;
+       if (!fetching)
+               return 1;
+
+       flushes = 0;
        retval = -1;
-       while (fgets(line, sizeof(line), revs) != NULL) {
-               unsigned char sha1[20];
-               if (get_sha1_hex(line, sha1))
-                       die("git-fetch-pack: expected object name, got crud");
+       while ((sha1 = get_rev())) {
                packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
+               if (verbose)
+                       fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
                if (!(31 & ++count)) {
                        packet_flush(fd[1]);
                        flushes++;
@@ -38,26 +183,159 @@ static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *rem
                        if (get_ack(fd[0], result_sha1)) {
                                flushes = 0;
                                retval = 0;
+                               if (verbose)
+                                       fprintf(stderr, "got ack\n");
                                break;
                        }
                        flushes--;
                }
        }
-       pclose(revs);
+
        packet_write(fd[1], "done\n");
+       if (verbose)
+               fprintf(stderr, "done\n");
+       if (retval != 0)
+               flushes++;
        while (flushes) {
                flushes--;
-               if (get_ack(fd[0], result_sha1))
+               if (get_ack(fd[0], result_sha1)) {
+                       if (verbose)
+                               fprintf(stderr, "got ack\n");
                        return 0;
+               }
+       }
+       return retval;
+}
+
+static struct commit_list *complete = NULL;
+
+static int mark_complete(const char *path, const unsigned char *sha1)
+{
+       struct object *o = parse_object(sha1);
+
+       while (o && o->type == tag_type) {
+               struct tag *t = (struct tag *) o;
+               if (!t->tagged)
+                       break; /* broken repository */
+               o->flags |= COMPLETE;
+               o = parse_object(t->tagged->sha1);
+       }
+       if (o && o->type == commit_type) {
+               struct commit *commit = (struct commit *)o;
+               commit->object.flags |= COMPLETE;
+               insert_by_date(commit, &complete);
+       }
+       return 0;
+}
+
+static void mark_recent_complete_commits(unsigned long cutoff)
+{
+       while (complete && cutoff <= complete->item->date) {
+               if (verbose)
+                       fprintf(stderr, "Marking %s as complete\n",
+                               sha1_to_hex(complete->item->object.sha1));
+               pop_most_recent_commit(&complete, COMPLETE);
+       }
+}
+
+static void filter_refs(struct ref **refs, int nr_match, char **match)
+{
+       struct ref *prev, *current, *next;
+
+       if (!nr_match)
+               return;
+
+       for (prev = NULL, current = *refs; current; current = next) {
+               next = current->next;
+               if ((!memcmp(current->name, "refs/", 5) &&
+                                       check_ref_format(current->name + 5)) ||
+                               !path_match(current->name, nr_match, match)) {
+                       if (prev == NULL)
+                               *refs = next;
+                       else
+                               prev->next = next;
+                       free(current);
+               } else
+                       prev = current;
+       }
+}
+
+static int everything_local(struct ref **refs, int nr_match, char **match)
+{
+       struct ref *ref;
+       int retval;
+       unsigned long cutoff = 0;
+
+       track_object_refs = 0;
+       save_commit_buffer = 0;
+
+       for (ref = *refs; ref; ref = ref->next) {
+               struct object *o;
+
+               o = parse_object(ref->old_sha1);
+               if (!o)
+                       continue;
+
+               /* We already have it -- which may mean that we were
+                * in sync with the other side at some time after
+                * that (it is OK if we guess wrong here).
+                */
+               if (o->type == commit_type) {
+                       struct commit *commit = (struct commit *)o;
+                       if (!cutoff || cutoff < commit->date)
+                               cutoff = commit->date;
+               }
+       }
+
+       for_each_ref(mark_complete);
+       if (cutoff)
+               mark_recent_complete_commits(cutoff);
+
+       /*
+        * Mark all complete remote refs as common refs.
+        * Don't mark them common yet; the server has to be told so first.
+        */
+       for (ref = *refs; ref; ref = ref->next) {
+               struct object *o = deref_tag(lookup_object(ref->old_sha1));
+
+               if (!o || o->type != commit_type || !(o->flags & COMPLETE))
+                       continue;
+
+               if (!(o->flags & SEEN)) {
+                       rev_list_push((struct commit *)o, COMMON_REF | SEEN);
+
+                       mark_common((struct commit *)o, 1, 1);
+               }
+       }
+
+       filter_refs(refs, nr_match, match);
+
+       for (retval = 1, ref = *refs; ref ; ref = ref->next) {
+               const unsigned char *remote = ref->old_sha1;
+               unsigned char local[20];
+               struct object *o;
+
+               o = lookup_object(remote);
+               if (!o || !(o->flags & COMPLETE)) {
+                       retval = 0;
+                       if (!verbose)
+                               continue;
+                       fprintf(stderr,
+                               "want %s (%s)\n", sha1_to_hex(remote),
+                               ref->name);
+                       continue;
+               }
+
+               memcpy(ref->new_sha1, local, 20);
+               if (!verbose)
+                       continue;
+               fprintf(stderr,
+                       "already have %s (%s)\n", sha1_to_hex(remote),
+                       ref->name);
        }
        return retval;
 }
 
-/*
- * Eventually we'll want to be able to fetch multiple heads.
- *
- * Right now we'll just require a single match.
- */
 static int fetch_pack(int fd[2], int nr_match, char **match)
 {
        struct ref *ref;
@@ -65,17 +343,17 @@ static int fetch_pack(int fd[2], int nr_match, char **match)
        int status;
        pid_t pid;
 
-       get_remote_heads(fd[0], &ref, nr_match, match);
+       get_remote_heads(fd[0], &ref, 0, NULL, 0);
        if (!ref) {
                packet_flush(fd[1]);
                die("no matching remote head");
        }
-       if (ref->next) {
+       if (everything_local(&ref, nr_match, match)) {
                packet_flush(fd[1]);
-               die("multiple remote heads");
+               goto all_done;
        }
-       if (find_common(fd, sha1, ref->old_sha1) < 0)
-               die("git-fetch-pack: no common commits");
+       if (find_common(fd, sha1, ref) < 0)
+               fprintf(stderr, "warning: no common commits\n");
        pid = fork();
        if (pid < 0)
                die("git-fetch-pack: unable to fork off git-unpack-objects");
@@ -97,7 +375,12 @@ static int fetch_pack(int fd[2], int nr_match, char **match)
                int code = WEXITSTATUS(status);
                if (code)
                        die("git-unpack-objects died with error code %d", code);
-               puts(sha1_to_hex(ref->old_sha1));
+all_done:
+               while (ref) {
+                       printf("%s %s\n",
+                              sha1_to_hex(ref->old_sha1), ref->name);
+                       ref = ref->next;
+               }
                return 0;
        }
        if (WIFSIGNALED(status)) {
@@ -124,6 +407,14 @@ int main(int argc, char **argv)
                                exec = arg + 7;
                                continue;
                        }
+                       if (!strcmp("-q", arg)) {
+                               quiet = 1;
+                               continue;
+                       }
+                       if (!strcmp("-v", arg)) {
+                               verbose = 1;
+                               continue;
+                       }
                        usage(fetch_pack_usage);
                }
                dest = arg;