send-pack.con commit git-merge-tree: generalize the "traverse <n> trees in sync" functionality (164dcb9)
   1#include "cache.h"
   2#include "commit.h"
   3#include "tag.h"
   4#include "refs.h"
   5#include "pkt-line.h"
   6#include "exec_cmd.h"
   7
   8static const char send_pack_usage[] =
   9"git-send-pack [--all] [--exec=git-receive-pack] <remote> [<head>...]\n"
  10"  --all and explicit <head> specification are mutually exclusive.";
  11static const char *exec = "git-receive-pack";
  12static int verbose = 0;
  13static int send_all = 0;
  14static int force_update = 0;
  15
  16static int is_zero_sha1(const unsigned char *sha1)
  17{
  18        int i;
  19
  20        for (i = 0; i < 20; i++) {
  21                if (*sha1++)
  22                        return 0;
  23        }
  24        return 1;
  25}
  26
  27static void exec_pack_objects(void)
  28{
  29        static char *args[] = {
  30                "pack-objects",
  31                "--stdout",
  32                NULL
  33        };
  34        execv_git_cmd(args);
  35        die("git-pack-objects exec failed (%s)", strerror(errno));
  36}
  37
  38static void exec_rev_list(struct ref *refs)
  39{
  40        static char *args[1000];
  41        int i = 0;
  42
  43        args[i++] = "rev-list"; /* 0 */
  44        args[i++] = "--objects";        /* 1 */
  45        while (refs) {
  46                char *buf = malloc(100);
  47                if (i > 900)
  48                        die("git-rev-list environment overflow");
  49                if (!is_zero_sha1(refs->old_sha1) &&
  50                    has_sha1_file(refs->old_sha1)) {
  51                        args[i++] = buf;
  52                        snprintf(buf, 50, "^%s", sha1_to_hex(refs->old_sha1));
  53                        buf += 50;
  54                }
  55                if (!is_zero_sha1(refs->new_sha1)) {
  56                        args[i++] = buf;
  57                        snprintf(buf, 50, "%s", sha1_to_hex(refs->new_sha1));
  58                }
  59                refs = refs->next;
  60        }
  61        args[i] = NULL;
  62        execv_git_cmd(args);
  63        die("git-rev-list exec failed (%s)", strerror(errno));
  64}
  65
  66static void rev_list(int fd, struct ref *refs)
  67{
  68        int pipe_fd[2];
  69        pid_t pack_objects_pid;
  70
  71        if (pipe(pipe_fd) < 0)
  72                die("rev-list setup: pipe failed");
  73        pack_objects_pid = fork();
  74        if (!pack_objects_pid) {
  75                dup2(pipe_fd[0], 0);
  76                dup2(fd, 1);
  77                close(pipe_fd[0]);
  78                close(pipe_fd[1]);
  79                close(fd);
  80                exec_pack_objects();
  81                die("pack-objects setup failed");
  82        }
  83        if (pack_objects_pid < 0)
  84                die("pack-objects fork failed");
  85        dup2(pipe_fd[1], 1);
  86        close(pipe_fd[0]);
  87        close(pipe_fd[1]);
  88        close(fd);
  89        exec_rev_list(refs);
  90}
  91
  92static int pack_objects(int fd, struct ref *refs)
  93{
  94        pid_t rev_list_pid;
  95
  96        rev_list_pid = fork();
  97        if (!rev_list_pid) {
  98                rev_list(fd, refs);
  99                die("rev-list setup failed");
 100        }
 101        if (rev_list_pid < 0)
 102                die("rev-list fork failed");
 103        /*
 104         * We don't wait for the rev-list pipeline in the parent:
 105         * we end up waiting for the other end instead
 106         */
 107        return 0;
 108}
 109
 110static void unmark_and_free(struct commit_list *list, unsigned int mark)
 111{
 112        while (list) {
 113                struct commit_list *temp = list;
 114                temp->item->object.flags &= ~mark;
 115                list = temp->next;
 116                free(temp);
 117        }
 118}
 119
 120static int ref_newer(const unsigned char *new_sha1,
 121                     const unsigned char *old_sha1)
 122{
 123        struct object *o;
 124        struct commit *old, *new;
 125        struct commit_list *list, *used;
 126        int found = 0;
 127
 128        /* Both new and old must be commit-ish and new is descendant of
 129         * old.  Otherwise we require --force.
 130         */
 131        o = deref_tag(parse_object(old_sha1), NULL, 0);
 132        if (!o || o->type != commit_type)
 133                return 0;
 134        old = (struct commit *) o;
 135
 136        o = deref_tag(parse_object(new_sha1), NULL, 0);
 137        if (!o || o->type != commit_type)
 138                return 0;
 139        new = (struct commit *) o;
 140
 141        if (parse_commit(new) < 0)
 142                return 0;
 143
 144        used = list = NULL;
 145        commit_list_insert(new, &list);
 146        while (list) {
 147                new = pop_most_recent_commit(&list, 1);
 148                commit_list_insert(new, &used);
 149                if (new == old) {
 150                        found = 1;
 151                        break;
 152                }
 153        }
 154        unmark_and_free(list, 1);
 155        unmark_and_free(used, 1);
 156        return found;
 157}
 158
 159static struct ref *local_refs, **local_tail;
 160static struct ref *remote_refs, **remote_tail;
 161
 162static int one_local_ref(const char *refname, const unsigned char *sha1)
 163{
 164        struct ref *ref;
 165        int len = strlen(refname) + 1;
 166        ref = xcalloc(1, sizeof(*ref) + len);
 167        memcpy(ref->new_sha1, sha1, 20);
 168        memcpy(ref->name, refname, len);
 169        *local_tail = ref;
 170        local_tail = &ref->next;
 171        return 0;
 172}
 173
 174static void get_local_heads(void)
 175{
 176        local_tail = &local_refs;
 177        for_each_ref(one_local_ref);
 178}
 179
 180static int receive_status(int in)
 181{
 182        char line[1000];
 183        int ret = 0;
 184        int len = packet_read_line(in, line, sizeof(line));
 185        if (len < 10 || memcmp(line, "unpack ", 7)) {
 186                fprintf(stderr, "did not receive status back\n");
 187                return -1;
 188        }
 189        if (memcmp(line, "unpack ok\n", 10)) {
 190                fputs(line, stderr);
 191                ret = -1;
 192        }
 193        while (1) {
 194                len = packet_read_line(in, line, sizeof(line));
 195                if (!len)
 196                        break;
 197                if (len < 3 ||
 198                    (memcmp(line, "ok", 2) && memcmp(line, "ng", 2))) {
 199                        fprintf(stderr, "protocol error: %s\n", line);
 200                        ret = -1;
 201                        break;
 202                }
 203                if (!memcmp(line, "ok", 2))
 204                        continue;
 205                fputs(line, stderr);
 206                ret = -1;
 207        }
 208        return ret;
 209}
 210
 211static int send_pack(int in, int out, int nr_refspec, char **refspec)
 212{
 213        struct ref *ref;
 214        int new_refs;
 215        int ret = 0;
 216        int ask_for_status_report = 0;
 217        int expect_status_report = 0;
 218
 219        /* No funny business with the matcher */
 220        remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
 221        get_local_heads();
 222
 223        /* Does the other end support the reporting? */
 224        if (server_supports("report-status"))
 225                ask_for_status_report = 1;
 226
 227        /* match them up */
 228        if (!remote_tail)
 229                remote_tail = &remote_refs;
 230        if (match_refs(local_refs, remote_refs, &remote_tail,
 231                       nr_refspec, refspec, send_all))
 232                return -1;
 233
 234        if (!remote_refs) {
 235                fprintf(stderr, "No refs in common and none specified; doing nothing.\n");
 236                return 0;
 237        }
 238
 239        /*
 240         * Finally, tell the other end!
 241         */
 242        new_refs = 0;
 243        for (ref = remote_refs; ref; ref = ref->next) {
 244                char old_hex[60], *new_hex;
 245                if (!ref->peer_ref)
 246                        continue;
 247                if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
 248                        if (verbose)
 249                                fprintf(stderr, "'%s': up-to-date\n", ref->name);
 250                        continue;
 251                }
 252
 253                /* This part determines what can overwrite what.
 254                 * The rules are:
 255                 *
 256                 * (0) you can always use --force or +A:B notation to
 257                 *     selectively force individual ref pairs.
 258                 *
 259                 * (1) if the old thing does not exist, it is OK.
 260                 *
 261                 * (2) if you do not have the old thing, you are not allowed
 262                 *     to overwrite it; you would not know what you are losing
 263                 *     otherwise.
 264                 *
 265                 * (3) if both new and old are commit-ish, and new is a
 266                 *     descendant of old, it is OK.
 267                 */
 268
 269                if (!force_update &&
 270                    !is_zero_sha1(ref->old_sha1) &&
 271                    !ref->force) {
 272                        if (!has_sha1_file(ref->old_sha1) ||
 273                            !ref_newer(ref->peer_ref->new_sha1,
 274                                       ref->old_sha1)) {
 275                                /* We do not have the remote ref, or
 276                                 * we know that the remote ref is not
 277                                 * an ancestor of what we are trying to
 278                                 * push.  Either way this can be losing
 279                                 * commits at the remote end and likely
 280                                 * we were not up to date to begin with.
 281                                 */
 282                                error("remote '%s' is not a strict "
 283                                      "subset of local ref '%s'. "
 284                                      "maybe you are not up-to-date and "
 285                                      "need to pull first?",
 286                                      ref->name,
 287                                      ref->peer_ref->name);
 288                                ret = -2;
 289                                continue;
 290                        }
 291                }
 292                memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
 293                if (is_zero_sha1(ref->new_sha1)) {
 294                        error("cannot happen anymore");
 295                        ret = -3;
 296                        continue;
 297                }
 298                new_refs++;
 299                strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 300                new_hex = sha1_to_hex(ref->new_sha1);
 301
 302                if (ask_for_status_report) {
 303                        packet_write(out, "%s %s %s%c%s",
 304                                     old_hex, new_hex, ref->name, 0,
 305                                     "report-status");
 306                        ask_for_status_report = 0;
 307                        expect_status_report = 1;
 308                }
 309                else
 310                        packet_write(out, "%s %s %s",
 311                                     old_hex, new_hex, ref->name);
 312                fprintf(stderr, "updating '%s'", ref->name);
 313                if (strcmp(ref->name, ref->peer_ref->name))
 314                        fprintf(stderr, " using '%s'", ref->peer_ref->name);
 315                fprintf(stderr, "\n  from %s\n  to   %s\n", old_hex, new_hex);
 316        }
 317
 318        packet_flush(out);
 319        if (new_refs)
 320                pack_objects(out, remote_refs);
 321        close(out);
 322
 323        if (expect_status_report) {
 324                if (receive_status(in))
 325                        ret = -4;
 326        }
 327
 328        if (!new_refs && ret == 0)
 329                fprintf(stderr, "Everything up-to-date\n");
 330        return ret;
 331}
 332
 333
 334int main(int argc, char **argv)
 335{
 336        int i, nr_heads = 0;
 337        char *dest = NULL;
 338        char **heads = NULL;
 339        int fd[2], ret;
 340        pid_t pid;
 341
 342        setup_git_directory();
 343        argv++;
 344        for (i = 1; i < argc; i++, argv++) {
 345                char *arg = *argv;
 346
 347                if (*arg == '-') {
 348                        if (!strncmp(arg, "--exec=", 7)) {
 349                                exec = arg + 7;
 350                                continue;
 351                        }
 352                        if (!strcmp(arg, "--all")) {
 353                                send_all = 1;
 354                                continue;
 355                        }
 356                        if (!strcmp(arg, "--force")) {
 357                                force_update = 1;
 358                                continue;
 359                        }
 360                        if (!strcmp(arg, "--verbose")) {
 361                                verbose = 1;
 362                                continue;
 363                        }
 364                        usage(send_pack_usage);
 365                }
 366                if (!dest) {
 367                        dest = arg;
 368                        continue;
 369                }
 370                heads = argv;
 371                nr_heads = argc - i;
 372                break;
 373        }
 374        if (!dest)
 375                usage(send_pack_usage);
 376        if (heads && send_all)
 377                usage(send_pack_usage);
 378        pid = git_connect(fd, dest, exec);
 379        if (pid < 0)
 380                return 1;
 381        ret = send_pack(fd[0], fd[1], nr_heads, heads);
 382        close(fd[0]);
 383        close(fd[1]);
 384        finish_connect(pid);
 385        return ret;
 386}