git-pull: allow pulling into an empty repository
[gitweb.git] / fetch-pack.c
index 969e72a7816701ed3f86ab42db1472346cab991e..0a169dce8574102a03c978bb24f8d0664f1fc9b6 100644 (file)
 #include "pkt-line.h"
 #include "commit.h"
 #include "tag.h"
-#include <time.h>
+#include "exec_cmd.h"
+#include "sideband.h"
 #include <sys/wait.h>
 
+static int keep_pack;
 static int quiet;
 static int verbose;
+static int fetch_all;
 static const char fetch_pack_usage[] =
-"git-fetch-pack [-q] [-v] [--exec=upload-pack] [host:]directory <refs>...";
+"git-fetch-pack [--all] [-q] [-v] [-k] [--thin] [--exec=upload-pack] [host:]directory <refs>...";
 static const char *exec = "git-upload-pack";
 
+#define COMPLETE       (1U << 0)
+#define COMMON         (1U << 1)
+#define COMMON_REF     (1U << 2)
+#define SEEN           (1U << 3)
+#define POPPED         (1U << 4)
+
+/*
+ * After sending this many "have"s if we do not get any new ACK , we
+ * give up traversing our history.
+ */
+#define MAX_IN_VAIN 256
+
+static struct commit_list *rev_list;
+static int non_common_revs, multi_ack, use_thin_pack, use_sideband;
+
+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, int flag, void *cb_data)
+{
+       struct object *o = deref_tag(parse_object(sha1), path, 0);
+
+       if (o && o->type == OBJ_COMMIT)
+               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(void)
+{
+       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)
 {
        int fetching;
-       static char line[1000];
        int count = 0, flushes = 0, retval;
-       FILE *revs;
+       const unsigned char *sha1;
+       unsigned in_vain = 0;
+       int got_continue = 0;
 
-       revs = popen("git-rev-list $(git-rev-parse --all)", "r");
-       if (!revs)
-               die("unable to run 'git-rev-list'");
+       for_each_ref(rev_list_insert_ref, NULL);
 
        fetching = 0;
        for ( ; refs ; refs = refs->next) {
                unsigned char *remote = refs->old_sha1;
-               unsigned char *local = refs->new_sha1;
+               struct object *o;
 
-               if (!memcmp(remote, local, 20))
+               /*
+                * 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;
-               packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
+               }
+
+               if (!fetching)
+                       packet_write(fd[1], "want %s%s%s%s%s%s\n",
+                                    sha1_to_hex(remote),
+                                    (multi_ack ? " multi_ack" : ""),
+                                    (use_sideband == 2 ? " side-band-64k" : ""),
+                                    (use_sideband == 1 ? " side-band" : ""),
+                                    (use_thin_pack ? " thin-pack" : ""),
+                                    " ofs-delta");
+               else
+                       packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
                fetching++;
        }
        packet_flush(fd[1]);
        if (!fetching)
                return 1;
-       flushes = 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));
+               in_vain++;
                if (!(31 & ++count)) {
+                       int ack;
+
                        packet_flush(fd[1]);
                        flushes++;
 
@@ -56,43 +203,72 @@ static int find_common(int fd[2], unsigned char *result_sha1,
                         */
                        if (count == 32)
                                continue;
-                       if (get_ack(fd[0], result_sha1)) {
-                               flushes = 0;
-                               retval = 0;
+
+                       do {
+                               ack = get_ack(fd[0], result_sha1);
+                               if (verbose && ack)
+                                       fprintf(stderr, "got ack %d %s\n", ack,
+                                                       sha1_to_hex(result_sha1));
+                               if (ack == 1) {
+                                       flushes = 0;
+                                       multi_ack = 0;
+                                       retval = 0;
+                                       goto done;
+                               } else if (ack == 2) {
+                                       struct commit *commit =
+                                               lookup_commit(result_sha1);
+                                       mark_common(commit, 0, 1);
+                                       retval = 0;
+                                       in_vain = 0;
+                                       got_continue = 1;
+                               }
+                       } while (ack);
+                       flushes--;
+                       if (got_continue && MAX_IN_VAIN < in_vain) {
                                if (verbose)
-                                       fprintf(stderr, "got ack\n");
-                               break;
+                                       fprintf(stderr, "giving up\n");
+                               break; /* give up */
                        }
-                       flushes--;
                }
        }
-       pclose(revs);
+done:
        packet_write(fd[1], "done\n");
        if (verbose)
                fprintf(stderr, "done\n");
-       while (flushes) {
-               flushes--;
-               if (get_ack(fd[0], result_sha1)) {
+       if (retval != 0) {
+               multi_ack = 0;
+               flushes++;
+       }
+       while (flushes || multi_ack) {
+               int ack = get_ack(fd[0], result_sha1);
+               if (ack) {
                        if (verbose)
-                               fprintf(stderr, "got ack\n");
-                       return 0;
+                               fprintf(stderr, "got ack (%d) %s\n", ack,
+                                       sha1_to_hex(result_sha1));
+                       if (ack == 1)
+                               return 0;
+                       multi_ack = 1;
+                       continue;
                }
+               flushes--;
        }
        return retval;
 }
 
-#define COMPLETE       (1U << 0)
-static struct commit_list *complete = NULL;
+static struct commit_list *complete;
 
-static int mark_complete(const char *path, const unsigned char *sha1)
+static int mark_complete(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
        struct object *o = parse_object(sha1);
 
-       while (o && o->type == tag_type) {
+       while (o && o->type == OBJ_TAG) {
+               struct tag *t = (struct tag *) o;
+               if (!t->tagged)
+                       break; /* broken repository */
                o->flags |= COMPLETE;
-               o = parse_object(((struct tag *)o)->tagged->sha1);
+               o = parse_object(t->tagged->sha1);
        }
-       if (o->type == commit_type) {
+       if (o && o->type == OBJ_COMMIT) {
                struct commit *commit = (struct commit *)o;
                commit->object.flags |= COMPLETE;
                insert_by_date(commit, &complete);
@@ -110,7 +286,63 @@ static void mark_recent_complete_commits(unsigned long cutoff)
        }
 }
 
-static int everything_local(struct ref *refs)
+static void filter_refs(struct ref **refs, int nr_match, char **match)
+{
+       struct ref **return_refs;
+       struct ref *newlist = NULL;
+       struct ref **newtail = &newlist;
+       struct ref *ref, *next;
+       struct ref *fastarray[32];
+
+       if (nr_match && !fetch_all) {
+               if (ARRAY_SIZE(fastarray) < nr_match)
+                       return_refs = xcalloc(nr_match, sizeof(struct ref *));
+               else {
+                       return_refs = fastarray;
+                       memset(return_refs, 0, sizeof(struct ref *) * nr_match);
+               }
+       }
+       else
+               return_refs = NULL;
+
+       for (ref = *refs; ref; ref = next) {
+               next = ref->next;
+               if (!memcmp(ref->name, "refs/", 5) &&
+                   check_ref_format(ref->name + 5))
+                       ; /* trash */
+               else if (fetch_all) {
+                       *newtail = ref;
+                       ref->next = NULL;
+                       newtail = &ref->next;
+                       continue;
+               }
+               else {
+                       int order = path_match(ref->name, nr_match, match);
+                       if (order) {
+                               return_refs[order-1] = ref;
+                               continue; /* we will link it later */
+                       }
+               }
+               free(ref);
+       }
+
+       if (!fetch_all) {
+               int i;
+               for (i = 0; i < nr_match; i++) {
+                       ref = return_refs[i];
+                       if (ref) {
+                               *newtail = ref;
+                               ref->next = NULL;
+                               newtail = &ref->next;
+                       }
+               }
+               if (return_refs != fastarray)
+                       free(return_refs);
+       }
+       *refs = newlist;
+}
+
+static int everything_local(struct ref **refs, int nr_match, char **match)
 {
        struct ref *ref;
        int retval;
@@ -119,7 +351,7 @@ static int everything_local(struct ref *refs)
        track_object_refs = 0;
        save_commit_buffer = 0;
 
-       for (ref = refs; ref; ref = ref->next) {
+       for (ref = *refs; ref; ref = ref->next) {
                struct object *o;
 
                o = parse_object(ref->old_sha1);
@@ -130,95 +362,208 @@ static int everything_local(struct ref *refs)
                 * in sync with the other side at some time after
                 * that (it is OK if we guess wrong here).
                 */
-               if (o->type == commit_type) {
+               if (o->type == OBJ_COMMIT) {
                        struct commit *commit = (struct commit *)o;
                        if (!cutoff || cutoff < commit->date)
                                cutoff = commit->date;
                }
        }
 
-       for_each_ref(mark_complete);
+       for_each_ref(mark_complete, NULL);
        if (cutoff)
                mark_recent_complete_commits(cutoff);
 
-       for (retval = 1; refs ; refs = refs->next) {
-               const unsigned char *remote = refs->old_sha1;
+       /*
+        * 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),
+                                            NULL, 0);
+
+               if (!o || o->type != OBJ_COMMIT || !(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 = parse_object(remote);
+               o = lookup_object(remote);
                if (!o || !(o->flags & COMPLETE)) {
                        retval = 0;
                        if (!verbose)
                                continue;
                        fprintf(stderr,
                                "want %s (%s)\n", sha1_to_hex(remote),
-                               refs->name);
+                               ref->name);
                        continue;
                }
 
-               memcpy(refs->new_sha1, local, 20);
+               hashcpy(ref->new_sha1, local);
                if (!verbose)
                        continue;
                fprintf(stderr,
                        "already have %s (%s)\n", sha1_to_hex(remote),
-                       refs->name);
+                       ref->name);
        }
        return retval;
 }
 
-static int fetch_pack(int fd[2], int nr_match, char **match)
+static pid_t setup_sideband(int fd[2], int xd[2])
 {
-       struct ref *ref;
-       unsigned char sha1[20];
-       int status;
-       pid_t pid;
+       pid_t side_pid;
 
-       get_remote_heads(fd[0], &ref, nr_match, match, 1);
-       if (!ref) {
-               packet_flush(fd[1]);
-               die("no matching remote head");
+       if (!use_sideband) {
+               fd[0] = xd[0];
+               fd[1] = xd[1];
+               return 0;
        }
-       if (everything_local(ref)) {
-               packet_flush(fd[1]);
-               goto all_done;
+       /* xd[] is talking with upload-pack; subprocess reads from
+        * xd[0], spits out band#2 to stderr, and feeds us band#1
+        * through our fd[0].
+        */
+       if (pipe(fd) < 0)
+               die("fetch-pack: unable to set up pipe");
+       side_pid = fork();
+       if (side_pid < 0)
+               die("fetch-pack: unable to fork off sideband demultiplexer");
+       if (!side_pid) {
+               /* subprocess */
+               close(fd[0]);
+               if (xd[0] != xd[1])
+                       close(xd[1]);
+               if (recv_sideband("fetch-pack", xd[0], fd[1], 2))
+                       exit(1);
+               exit(0);
        }
-       if (find_common(fd, sha1, ref) < 0)
-               fprintf(stderr, "warning: no common commits\n");
+       close(xd[0]);
+       close(fd[1]);
+       fd[1] = xd[1];
+       return side_pid;
+}
+
+static int get_pack(int xd[2], const char **argv)
+{
+       int status;
+       pid_t pid, side_pid;
+       int fd[2];
+
+       side_pid = setup_sideband(fd, xd);
        pid = fork();
        if (pid < 0)
-               die("git-fetch-pack: unable to fork off git-unpack-objects");
+               die("fetch-pack: unable to fork off %s", argv[0]);
        if (!pid) {
                dup2(fd[0], 0);
                close(fd[0]);
                close(fd[1]);
-               execlp("git-unpack-objects", "git-unpack-objects",
-                      quiet ? "-q" : NULL, NULL);
-               die("git-unpack-objects exec failed");
+               execv_git_cmd(argv);
+               die("%s exec failed", argv[0]);
        }
        close(fd[0]);
        close(fd[1]);
        while (waitpid(pid, &status, 0) < 0) {
                if (errno != EINTR)
-                       die("waiting for git-unpack-objects: %s", strerror(errno));
+                       die("waiting for %s: %s", argv[0], strerror(errno));
        }
        if (WIFEXITED(status)) {
                int code = WEXITSTATUS(status);
                if (code)
-                       die("git-unpack-objects died with error code %d", code);
-all_done:
-               while (ref) {
-                       printf("%s %s\n",
-                              sha1_to_hex(ref->old_sha1), ref->name);
-                       ref = ref->next;
-               }
+                       die("%s died with error code %d", argv[0], code);
                return 0;
        }
        if (WIFSIGNALED(status)) {
                int sig = WTERMSIG(status);
-               die("git-unpack-objects died of signal %d", sig);
+               die("%s died of signal %d", argv[0], sig);
+       }
+       die("%s died of unnatural causes %d", argv[0], status);
+}
+
+static int explode_rx_pack(int xd[2])
+{
+       const char *argv[3] = { "unpack-objects", quiet ? "-q" : NULL, NULL };
+       return get_pack(xd, argv);
+}
+
+static int keep_rx_pack(int xd[2])
+{
+       const char *argv[6];
+       char keep_arg[256];
+       int n = 0;
+
+       argv[n++] = "index-pack";
+       argv[n++] = "--stdin";
+       if (!quiet)
+               argv[n++] = "-v";
+       if (use_thin_pack)
+               argv[n++] = "--fix-thin";
+       if (keep_pack > 1) {
+               int s = sprintf(keep_arg, "--keep=fetch-pack %i on ", getpid());
+               if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
+                       strcpy(keep_arg + s, "localhost");
+               argv[n++] = keep_arg;
        }
-       die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
+       argv[n] = NULL;
+       return get_pack(xd, argv);
+}
+
+static int fetch_pack(int fd[2], int nr_match, char **match)
+{
+       struct ref *ref;
+       unsigned char sha1[20];
+       int status;
+
+       get_remote_heads(fd[0], &ref, 0, NULL, 0);
+       if (server_supports("multi_ack")) {
+               if (verbose)
+                       fprintf(stderr, "Server supports multi_ack\n");
+               multi_ack = 1;
+       }
+       if (server_supports("side-band-64k")) {
+               if (verbose)
+                       fprintf(stderr, "Server supports side-band-64k\n");
+               use_sideband = 2;
+       }
+       else if (server_supports("side-band")) {
+               if (verbose)
+                       fprintf(stderr, "Server supports side-band\n");
+               use_sideband = 1;
+       }
+       if (!ref) {
+               packet_flush(fd[1]);
+               die("no matching remote head");
+       }
+       if (everything_local(&ref, nr_match, match)) {
+               packet_flush(fd[1]);
+               goto all_done;
+       }
+       if (find_common(fd, sha1, ref) < 0)
+               if (keep_pack != 1)
+                       /* When cloning, it is not unusual to have
+                        * no common commit.
+                        */
+                       fprintf(stderr, "warning: no common commits\n");
+
+       status = (keep_pack) ? keep_rx_pack(fd) : explode_rx_pack(fd);
+       if (status)
+               die("git-fetch-pack: fetch failed.");
+
+ all_done:
+       while (ref) {
+               printf("%s %s\n",
+                      sha1_to_hex(ref->old_sha1), ref->name);
+               ref = ref->next;
+       }
+       return 0;
 }
 
 int main(int argc, char **argv)
@@ -228,6 +573,8 @@ int main(int argc, char **argv)
        int fd[2];
        pid_t pid;
 
+       setup_git_directory();
+
        nr_heads = 0;
        heads = NULL;
        for (i = 1; i < argc; i++) {
@@ -238,10 +585,22 @@ int main(int argc, char **argv)
                                exec = arg + 7;
                                continue;
                        }
-                       if (!strcmp("-q", arg)) {
+                       if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
                                quiet = 1;
                                continue;
                        }
+                       if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
+                               keep_pack++;
+                               continue;
+                       }
+                       if (!strcmp("--thin", arg)) {
+                               use_thin_pack = 1;
+                               continue;
+                       }
+                       if (!strcmp("--all", arg)) {
+                               fetch_all = 1;
+                               continue;
+                       }
                        if (!strcmp("-v", arg)) {
                                verbose = 1;
                                continue;
@@ -261,6 +620,20 @@ int main(int argc, char **argv)
        ret = fetch_pack(fd, nr_heads, heads);
        close(fd[0]);
        close(fd[1]);
-       finish_connect(pid);
-       return ret;
+       ret |= finish_connect(pid);
+
+       if (!ret && nr_heads) {
+               /* If the heads to pull were given, we should have
+                * consumed all of them by matching the remote.
+                * Otherwise, 'git-fetch remote no-such-ref' would
+                * silently succeed without issuing an error.
+                */
+               for (i = 0; i < nr_heads; i++)
+                       if (heads[i] && heads[i][0]) {
+                               error("no such remote ref %s", heads[i]);
+                               ret = 1;
+                       }
+       }
+
+       return !!ret;
 }