upload-pack.con commit simple euristic for further free packing improvements (4e8da19)
   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#include "exec_cmd.h"
   8
   9static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  10
  11#define THEY_HAVE (1U << 0)
  12#define OUR_REF (1U << 1)
  13#define WANTED (1U << 2)
  14#define MAX_HAS 256
  15#define MAX_NEEDS 256
  16static int nr_has = 0, nr_needs = 0, multi_ack = 0, nr_our_refs = 0;
  17static int use_thin_pack = 0;
  18static unsigned char has_sha1[MAX_HAS][20];
  19static unsigned char needs_sha1[MAX_NEEDS][20];
  20static unsigned int timeout = 0;
  21
  22static void reset_timeout(void)
  23{
  24        alarm(timeout);
  25}
  26
  27static int strip(char *line, int len)
  28{
  29        if (len && line[len-1] == '\n')
  30                line[--len] = 0;
  31        return len;
  32}
  33
  34static void create_pack_file(void)
  35{
  36        int fd[2];
  37        pid_t pid;
  38        int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
  39
  40        if (pipe(fd) < 0)
  41                die("git-upload-pack: unable to create pipe");
  42        pid = fork();
  43        if (pid < 0)
  44                die("git-upload-pack: unable to fork git-rev-list");
  45
  46        if (!pid) {
  47                int i;
  48                int args;
  49                const char **argv;
  50                char *buf;
  51                char **p;
  52
  53                if (create_full_pack) {
  54                        args = 10;
  55                        use_thin_pack = 0; /* no point doing it */
  56                }
  57                else
  58                        args = nr_has + nr_needs + 5;
  59                p = xmalloc(args * sizeof(char *));
  60                argv = (const char **) p;
  61                buf = xmalloc(args * 45);
  62
  63                dup2(fd[1], 1);
  64                close(0);
  65                close(fd[0]);
  66                close(fd[1]);
  67                *p++ = "rev-list";
  68                *p++ = use_thin_pack ? "--objects-edge" : "--objects";
  69                if (create_full_pack || MAX_NEEDS <= nr_needs)
  70                        *p++ = "--all";
  71                else {
  72                        for (i = 0; i < nr_needs; i++) {
  73                                *p++ = buf;
  74                                memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
  75                                buf += 41;
  76                        }
  77                }
  78                if (!create_full_pack)
  79                        for (i = 0; i < nr_has; i++) {
  80                                *p++ = buf;
  81                                *buf++ = '^';
  82                                memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
  83                                buf += 41;
  84                        }
  85                *p++ = NULL;
  86                execv_git_cmd(argv);
  87                die("git-upload-pack: unable to exec git-rev-list");
  88        }
  89        dup2(fd[0], 0);
  90        close(fd[0]);
  91        close(fd[1]);
  92        execl_git_cmd("pack-objects", "--stdout", NULL);
  93        die("git-upload-pack: unable to exec git-pack-objects");
  94}
  95
  96static int got_sha1(char *hex, unsigned char *sha1)
  97{
  98        if (get_sha1_hex(hex, sha1))
  99                die("git-upload-pack: expected SHA1 object, got '%s'", hex);
 100        if (!has_sha1_file(sha1))
 101                return 0;
 102        if (nr_has < MAX_HAS) {
 103                struct object *o = lookup_object(sha1);
 104                if (!(o && o->parsed))
 105                        o = parse_object(sha1);
 106                if (!o)
 107                        die("oops (%s)", sha1_to_hex(sha1));
 108                if (o->type == commit_type) {
 109                        struct commit_list *parents;
 110                        if (o->flags & THEY_HAVE)
 111                                return 0;
 112                        o->flags |= THEY_HAVE;
 113                        for (parents = ((struct commit*)o)->parents;
 114                             parents;
 115                             parents = parents->next)
 116                                parents->item->object.flags |= THEY_HAVE;
 117                }
 118                memcpy(has_sha1[nr_has++], sha1, 20);
 119        }
 120        return 1;
 121}
 122
 123static int get_common_commits(void)
 124{
 125        static char line[1000];
 126        unsigned char sha1[20], last_sha1[20];
 127        int len;
 128
 129        track_object_refs = 0;
 130        save_commit_buffer = 0;
 131
 132        for(;;) {
 133                len = packet_read_line(0, line, sizeof(line));
 134                reset_timeout();
 135
 136                if (!len) {
 137                        if (nr_has == 0 || multi_ack)
 138                                packet_write(1, "NAK\n");
 139                        continue;
 140                }
 141                len = strip(line, len);
 142                if (!strncmp(line, "have ", 5)) {
 143                        if (got_sha1(line+5, sha1) &&
 144                                        (multi_ack || nr_has == 1)) {
 145                                if (nr_has >= MAX_HAS)
 146                                        multi_ack = 0;
 147                                packet_write(1, "ACK %s%s\n",
 148                                        sha1_to_hex(sha1),
 149                                        multi_ack ?  " continue" : "");
 150                                if (multi_ack)
 151                                        memcpy(last_sha1, sha1, 20);
 152                        }
 153                        continue;
 154                }
 155                if (!strcmp(line, "done")) {
 156                        if (nr_has > 0) {
 157                                if (multi_ack)
 158                                        packet_write(1, "ACK %s\n",
 159                                                        sha1_to_hex(last_sha1));
 160                                return 0;
 161                        }
 162                        packet_write(1, "NAK\n");
 163                        return -1;
 164                }
 165                die("git-upload-pack: expected SHA1 list, got '%s'", line);
 166        }
 167}
 168
 169static int receive_needs(void)
 170{
 171        static char line[1000];
 172        int len, needs;
 173
 174        needs = 0;
 175        for (;;) {
 176                struct object *o;
 177                unsigned char dummy[20], *sha1_buf;
 178                len = packet_read_line(0, line, sizeof(line));
 179                reset_timeout();
 180                if (!len)
 181                        return needs;
 182
 183                sha1_buf = dummy;
 184                if (needs == MAX_NEEDS) {
 185                        fprintf(stderr,
 186                                "warning: supporting only a max of %d requests. "
 187                                "sending everything instead.\n",
 188                                MAX_NEEDS);
 189                }
 190                else if (needs < MAX_NEEDS)
 191                        sha1_buf = needs_sha1[needs];
 192
 193                if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
 194                        die("git-upload-pack: protocol error, "
 195                            "expected to get sha, not '%s'", line);
 196                if (strstr(line+45, "multi_ack"))
 197                        multi_ack = 1;
 198                if (strstr(line+45, "thin-pack"))
 199                        use_thin_pack = 1;
 200
 201                /* We have sent all our refs already, and the other end
 202                 * should have chosen out of them; otherwise they are
 203                 * asking for nonsense.
 204                 *
 205                 * Hmph.  We may later want to allow "want" line that
 206                 * asks for something like "master~10" (symbolic)...
 207                 * would it make sense?  I don't know.
 208                 */
 209                o = lookup_object(sha1_buf);
 210                if (!o || !(o->flags & OUR_REF))
 211                        die("git-upload-pack: not our ref %s", line+5);
 212                if (!(o->flags & WANTED)) {
 213                        o->flags |= WANTED;
 214                        needs++;
 215                }
 216        }
 217}
 218
 219static int send_ref(const char *refname, const unsigned char *sha1)
 220{
 221        static char *capabilities = "multi_ack thin-pack";
 222        struct object *o = parse_object(sha1);
 223
 224        if (!o)
 225                die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
 226
 227        if (capabilities)
 228                packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 229                        0, capabilities);
 230        else
 231                packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 232        capabilities = NULL;
 233        if (!(o->flags & OUR_REF)) {
 234                o->flags |= OUR_REF;
 235                nr_our_refs++;
 236        }
 237        if (o->type == tag_type) {
 238                o = deref_tag(o, refname, 0);
 239                packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 240        }
 241        return 0;
 242}
 243
 244static int upload_pack(void)
 245{
 246        reset_timeout();
 247        head_ref(send_ref);
 248        for_each_ref(send_ref);
 249        packet_flush(1);
 250        nr_needs = receive_needs();
 251        if (!nr_needs)
 252                return 0;
 253        get_common_commits();
 254        create_pack_file();
 255        return 0;
 256}
 257
 258int main(int argc, char **argv)
 259{
 260        char *dir;
 261        int i;
 262        int strict = 0;
 263
 264        for (i = 1; i < argc; i++) {
 265                char *arg = argv[i];
 266
 267                if (arg[0] != '-')
 268                        break;
 269                if (!strcmp(arg, "--strict")) {
 270                        strict = 1;
 271                        continue;
 272                }
 273                if (!strncmp(arg, "--timeout=", 10)) {
 274                        timeout = atoi(arg+10);
 275                        continue;
 276                }
 277                if (!strcmp(arg, "--")) {
 278                        i++;
 279                        break;
 280                }
 281        }
 282        
 283        if (i != argc-1)
 284                usage(upload_pack_usage);
 285        dir = argv[i];
 286
 287        if (!enter_repo(dir, strict))
 288                die("'%s': unable to chdir or not a git archive", dir);
 289
 290        upload_pack();
 291        return 0;
 292}