Andrew's git - gitweb.git/blob

   1/*
   2 * Copyright (c) 2011, Google Inc.
   3 */
   4#include "cache.h"
   5#include "bulk-checkin.h"
   6#include "csum-file.h"
   7#include "pack.h"
   8#include "strbuf.h"
   9#include "packfile.h"
  10
  11static struct bulk_checkin_state {
  12        unsigned plugged:1;
  13
  14        char *pack_tmp_name;
  15        struct hashfile *f;
  16        off_t offset;
  17        struct pack_idx_option pack_idx_opts;
  18
  19        struct pack_idx_entry **written;
  20        uint32_t alloc_written;
  21        uint32_t nr_written;
  22} state;
  23
  24static void finish_bulk_checkin(struct bulk_checkin_state *state)
  25{
  26        struct object_id oid;
  27        struct strbuf packname = STRBUF_INIT;
  28        int i;
  29
  30        if (!state->f)
  31                return;
  32
  33        if (state->nr_written == 0) {
  34                close(state->f->fd);
  35                unlink(state->pack_tmp_name);
  36                goto clear_exit;
  37        } else if (state->nr_written == 1) {
  38                finalize_hashfile(state->f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
  39        } else {
  40                int fd = finalize_hashfile(state->f, oid.hash, 0);
  41                fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
  42                                         state->nr_written, oid.hash,
  43                                         state->offset);
  44                close(fd);
  45        }
  46
  47        strbuf_addf(&packname, "%s/pack/pack-", get_object_directory());
  48        finish_tmp_packfile(&packname, state->pack_tmp_name,
  49                            state->written, state->nr_written,
  50                            &state->pack_idx_opts, oid.hash);
  51        for (i = 0; i < state->nr_written; i++)
  52                free(state->written[i]);
  53
  54clear_exit:
  55        free(state->written);
  56        memset(state, 0, sizeof(*state));
  57
  58        strbuf_release(&packname);
  59        /* Make objects we just wrote available to ourselves */
  60        reprepare_packed_git();
  61}
  62
  63static int already_written(struct bulk_checkin_state *state, unsigned char sha1[])
  64{
  65        int i;
  66
  67        /* The object may already exist in the repository */
  68        if (has_sha1_file(sha1))
  69                return 1;
  70
  71        /* Might want to keep the list sorted */
  72        for (i = 0; i < state->nr_written; i++)
  73                if (!hashcmp(state->written[i]->oid.hash, sha1))
  74                        return 1;
  75
  76        /* This is a new object we need to keep */
  77        return 0;
  78}
  79
  80/*
  81 * Read the contents from fd for size bytes, streaming it to the
  82 * packfile in state while updating the hash in ctx. Signal a failure
  83 * by returning a negative value when the resulting pack would exceed
  84 * the pack size limit and this is not the first object in the pack,
  85 * so that the caller can discard what we wrote from the current pack
  86 * by truncating it and opening a new one. The caller will then call
  87 * us again after rewinding the input fd.
  88 *
  89 * The already_hashed_to pointer is kept untouched by the caller to
  90 * make sure we do not hash the same byte when we are called
  91 * again. This way, the caller does not have to checkpoint its hash
  92 * status before calling us just in case we ask it to call us again
  93 * with a new pack.
  94 */
  95static int stream_to_pack(struct bulk_checkin_state *state,
  96                          git_hash_ctx *ctx, off_t *already_hashed_to,
  97                          int fd, size_t size, enum object_type type,
  98                          const char *path, unsigned flags)
  99{
 100        git_zstream s;
 101        unsigned char obuf[16384];
 102        unsigned hdrlen;
 103        int status = Z_OK;
 104        int write_object = (flags & HASH_WRITE_OBJECT);
 105        off_t offset = 0;
 106
 107        git_deflate_init(&s, pack_compression_level);
 108
 109        hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
 110        s.next_out = obuf + hdrlen;
 111        s.avail_out = sizeof(obuf) - hdrlen;
 112
 113        while (status != Z_STREAM_END) {
 114                unsigned char ibuf[16384];
 115
 116                if (size && !s.avail_in) {
 117                        ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
 118                        ssize_t read_result = read_in_full(fd, ibuf, rsize);
 119                        if (read_result < 0)
 120                                die_errno("failed to read from '%s'", path);
 121                        if (read_result != rsize)
 122                                die("failed to read %d bytes from '%s'",
 123                                    (int)rsize, path);
 124                        offset += rsize;
 125                        if (*already_hashed_to < offset) {
 126                                size_t hsize = offset - *already_hashed_to;
 127                                if (rsize < hsize)
 128                                        hsize = rsize;
 129                                if (hsize)
 130                                        the_hash_algo->update_fn(ctx, ibuf, hsize);
 131                                *already_hashed_to = offset;
 132                        }
 133                        s.next_in = ibuf;
 134                        s.avail_in = rsize;
 135                        size -= rsize;
 136                }
 137
 138                status = git_deflate(&s, size ? 0 : Z_FINISH);
 139
 140                if (!s.avail_out || status == Z_STREAM_END) {
 141                        if (write_object) {
 142                                size_t written = s.next_out - obuf;
 143
 144                                /* would we bust the size limit? */
 145                                if (state->nr_written &&
 146                                    pack_size_limit_cfg &&
 147                                    pack_size_limit_cfg < state->offset + written) {
 148                                        git_deflate_abort(&s);
 149                                        return -1;
 150                                }
 151
 152                                hashwrite(state->f, obuf, written);
 153                                state->offset += written;
 154                        }
 155                        s.next_out = obuf;
 156                        s.avail_out = sizeof(obuf);
 157                }
 158
 159                switch (status) {
 160                case Z_OK:
 161                case Z_BUF_ERROR:
 162                case Z_STREAM_END:
 163                        continue;
 164                default:
 165                        die("unexpected deflate failure: %d", status);
 166                }
 167        }
 168        git_deflate_end(&s);
 169        return 0;
 170}
 171
 172/* Lazily create backing packfile for the state */
 173static void prepare_to_stream(struct bulk_checkin_state *state,
 174                              unsigned flags)
 175{
 176        if (!(flags & HASH_WRITE_OBJECT) || state->f)
 177                return;
 178
 179        state->f = create_tmp_packfile(&state->pack_tmp_name);
 180        reset_pack_idx_option(&state->pack_idx_opts);
 181
 182        /* Pretend we are going to write only one object */
 183        state->offset = write_pack_header(state->f, 1);
 184        if (!state->offset)
 185                die_errno("unable to write pack header");
 186}
 187
 188static int deflate_to_pack(struct bulk_checkin_state *state,
 189                           unsigned char result_sha1[],
 190                           int fd, size_t size,
 191                           enum object_type type, const char *path,
 192                           unsigned flags)
 193{
 194        off_t seekback, already_hashed_to;
 195        git_hash_ctx ctx;
 196        unsigned char obuf[16384];
 197        unsigned header_len;
 198        struct hashfile_checkpoint checkpoint;
 199        struct pack_idx_entry *idx = NULL;
 200
 201        seekback = lseek(fd, 0, SEEK_CUR);
 202        if (seekback == (off_t) -1)
 203                return error("cannot find the current offset");
 204
 205        header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
 206                               type_name(type), (uintmax_t)size) + 1;
 207        the_hash_algo->init_fn(&ctx);
 208        the_hash_algo->update_fn(&ctx, obuf, header_len);
 209
 210        /* Note: idx is non-NULL when we are writing */
 211        if ((flags & HASH_WRITE_OBJECT) != 0)
 212                idx = xcalloc(1, sizeof(*idx));
 213
 214        already_hashed_to = 0;
 215
 216        while (1) {
 217                prepare_to_stream(state, flags);
 218                if (idx) {
 219                        hashfile_checkpoint(state->f, &checkpoint);
 220                        idx->offset = state->offset;
 221                        crc32_begin(state->f);
 222                }
 223                if (!stream_to_pack(state, &ctx, &already_hashed_to,
 224                                    fd, size, type, path, flags))
 225                        break;
 226                /*
 227                 * Writing this object to the current pack will make
 228                 * it too big; we need to truncate it, start a new
 229                 * pack, and write into it.
 230                 */
 231                if (!idx)
 232                        die("BUG: should not happen");
 233                hashfile_truncate(state->f, &checkpoint);
 234                state->offset = checkpoint.offset;
 235                finish_bulk_checkin(state);
 236                if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
 237                        return error("cannot seek back");
 238        }
 239        the_hash_algo->final_fn(result_sha1, &ctx);
 240        if (!idx)
 241                return 0;
 242
 243        idx->crc32 = crc32_end(state->f);
 244        if (already_written(state, result_sha1)) {
 245                hashfile_truncate(state->f, &checkpoint);
 246                state->offset = checkpoint.offset;
 247                free(idx);
 248        } else {
 249                hashcpy(idx->oid.hash, result_sha1);
 250                ALLOC_GROW(state->written,
 251                           state->nr_written + 1,
 252                           state->alloc_written);
 253                state->written[state->nr_written++] = idx;
 254        }
 255        return 0;
 256}
 257
 258int index_bulk_checkin(unsigned char *sha1,
 259                       int fd, size_t size, enum object_type type,
 260                       const char *path, unsigned flags)
 261{
 262        int status = deflate_to_pack(&state, sha1, fd, size, type,
 263                                     path, flags);
 264        if (!state.plugged)
 265                finish_bulk_checkin(&state);
 266        return status;
 267}
 268
 269void plug_bulk_checkin(void)
 270{
 271        state.plugged = 1;
 272}
 273
 274void unplug_bulk_checkin(void)
 275{
 276        state.plugged = 0;
 277        if (state.f)
 278                finish_bulk_checkin(&state);
 279}