bulk-checkin.con commit Merge branch 'js/rebase-recreate-merge' (95dd4b2)
   1/*
   2 * Copyright (c) 2011, Google Inc.
   3 */
   4#include "cache.h"
   5#include "bulk-checkin.h"
   6#include "repository.h"
   7#include "csum-file.h"
   8#include "pack.h"
   9#include "strbuf.h"
  10#include "packfile.h"
  11
  12static struct bulk_checkin_state {
  13        unsigned plugged:1;
  14
  15        char *pack_tmp_name;
  16        struct hashfile *f;
  17        off_t offset;
  18        struct pack_idx_option pack_idx_opts;
  19
  20        struct pack_idx_entry **written;
  21        uint32_t alloc_written;
  22        uint32_t nr_written;
  23} state;
  24
  25static void finish_bulk_checkin(struct bulk_checkin_state *state)
  26{
  27        struct object_id oid;
  28        struct strbuf packname = STRBUF_INIT;
  29        int i;
  30
  31        if (!state->f)
  32                return;
  33
  34        if (state->nr_written == 0) {
  35                close(state->f->fd);
  36                unlink(state->pack_tmp_name);
  37                goto clear_exit;
  38        } else if (state->nr_written == 1) {
  39                finalize_hashfile(state->f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
  40        } else {
  41                int fd = finalize_hashfile(state->f, oid.hash, 0);
  42                fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
  43                                         state->nr_written, oid.hash,
  44                                         state->offset);
  45                close(fd);
  46        }
  47
  48        strbuf_addf(&packname, "%s/pack/pack-", get_object_directory());
  49        finish_tmp_packfile(&packname, state->pack_tmp_name,
  50                            state->written, state->nr_written,
  51                            &state->pack_idx_opts, oid.hash);
  52        for (i = 0; i < state->nr_written; i++)
  53                free(state->written[i]);
  54
  55clear_exit:
  56        free(state->written);
  57        memset(state, 0, sizeof(*state));
  58
  59        strbuf_release(&packname);
  60        /* Make objects we just wrote available to ourselves */
  61        reprepare_packed_git(the_repository);
  62}
  63
  64static int already_written(struct bulk_checkin_state *state, struct object_id *oid)
  65{
  66        int i;
  67
  68        /* The object may already exist in the repository */
  69        if (has_sha1_file(oid->hash))
  70                return 1;
  71
  72        /* Might want to keep the list sorted */
  73        for (i = 0; i < state->nr_written; i++)
  74                if (!oidcmp(&state->written[i]->oid, oid))
  75                        return 1;
  76
  77        /* This is a new object we need to keep */
  78        return 0;
  79}
  80
  81/*
  82 * Read the contents from fd for size bytes, streaming it to the
  83 * packfile in state while updating the hash in ctx. Signal a failure
  84 * by returning a negative value when the resulting pack would exceed
  85 * the pack size limit and this is not the first object in the pack,
  86 * so that the caller can discard what we wrote from the current pack
  87 * by truncating it and opening a new one. The caller will then call
  88 * us again after rewinding the input fd.
  89 *
  90 * The already_hashed_to pointer is kept untouched by the caller to
  91 * make sure we do not hash the same byte when we are called
  92 * again. This way, the caller does not have to checkpoint its hash
  93 * status before calling us just in case we ask it to call us again
  94 * with a new pack.
  95 */
  96static int stream_to_pack(struct bulk_checkin_state *state,
  97                          git_hash_ctx *ctx, off_t *already_hashed_to,
  98                          int fd, size_t size, enum object_type type,
  99                          const char *path, unsigned flags)
 100{
 101        git_zstream s;
 102        unsigned char obuf[16384];
 103        unsigned hdrlen;
 104        int status = Z_OK;
 105        int write_object = (flags & HASH_WRITE_OBJECT);
 106        off_t offset = 0;
 107
 108        git_deflate_init(&s, pack_compression_level);
 109
 110        hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
 111        s.next_out = obuf + hdrlen;
 112        s.avail_out = sizeof(obuf) - hdrlen;
 113
 114        while (status != Z_STREAM_END) {
 115                unsigned char ibuf[16384];
 116
 117                if (size && !s.avail_in) {
 118                        ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
 119                        ssize_t read_result = read_in_full(fd, ibuf, rsize);
 120                        if (read_result < 0)
 121                                die_errno("failed to read from '%s'", path);
 122                        if (read_result != rsize)
 123                                die("failed to read %d bytes from '%s'",
 124                                    (int)rsize, path);
 125                        offset += rsize;
 126                        if (*already_hashed_to < offset) {
 127                                size_t hsize = offset - *already_hashed_to;
 128                                if (rsize < hsize)
 129                                        hsize = rsize;
 130                                if (hsize)
 131                                        the_hash_algo->update_fn(ctx, ibuf, hsize);
 132                                *already_hashed_to = offset;
 133                        }
 134                        s.next_in = ibuf;
 135                        s.avail_in = rsize;
 136                        size -= rsize;
 137                }
 138
 139                status = git_deflate(&s, size ? 0 : Z_FINISH);
 140
 141                if (!s.avail_out || status == Z_STREAM_END) {
 142                        if (write_object) {
 143                                size_t written = s.next_out - obuf;
 144
 145                                /* would we bust the size limit? */
 146                                if (state->nr_written &&
 147                                    pack_size_limit_cfg &&
 148                                    pack_size_limit_cfg < state->offset + written) {
 149                                        git_deflate_abort(&s);
 150                                        return -1;
 151                                }
 152
 153                                hashwrite(state->f, obuf, written);
 154                                state->offset += written;
 155                        }
 156                        s.next_out = obuf;
 157                        s.avail_out = sizeof(obuf);
 158                }
 159
 160                switch (status) {
 161                case Z_OK:
 162                case Z_BUF_ERROR:
 163                case Z_STREAM_END:
 164                        continue;
 165                default:
 166                        die("unexpected deflate failure: %d", status);
 167                }
 168        }
 169        git_deflate_end(&s);
 170        return 0;
 171}
 172
 173/* Lazily create backing packfile for the state */
 174static void prepare_to_stream(struct bulk_checkin_state *state,
 175                              unsigned flags)
 176{
 177        if (!(flags & HASH_WRITE_OBJECT) || state->f)
 178                return;
 179
 180        state->f = create_tmp_packfile(&state->pack_tmp_name);
 181        reset_pack_idx_option(&state->pack_idx_opts);
 182
 183        /* Pretend we are going to write only one object */
 184        state->offset = write_pack_header(state->f, 1);
 185        if (!state->offset)
 186                die_errno("unable to write pack header");
 187}
 188
 189static int deflate_to_pack(struct bulk_checkin_state *state,
 190                           struct object_id *result_oid,
 191                           int fd, size_t size,
 192                           enum object_type type, const char *path,
 193                           unsigned flags)
 194{
 195        off_t seekback, already_hashed_to;
 196        git_hash_ctx ctx;
 197        unsigned char obuf[16384];
 198        unsigned header_len;
 199        struct hashfile_checkpoint checkpoint;
 200        struct pack_idx_entry *idx = NULL;
 201
 202        seekback = lseek(fd, 0, SEEK_CUR);
 203        if (seekback == (off_t) -1)
 204                return error("cannot find the current offset");
 205
 206        header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
 207                               type_name(type), (uintmax_t)size) + 1;
 208        the_hash_algo->init_fn(&ctx);
 209        the_hash_algo->update_fn(&ctx, obuf, header_len);
 210
 211        /* Note: idx is non-NULL when we are writing */
 212        if ((flags & HASH_WRITE_OBJECT) != 0)
 213                idx = xcalloc(1, sizeof(*idx));
 214
 215        already_hashed_to = 0;
 216
 217        while (1) {
 218                prepare_to_stream(state, flags);
 219                if (idx) {
 220                        hashfile_checkpoint(state->f, &checkpoint);
 221                        idx->offset = state->offset;
 222                        crc32_begin(state->f);
 223                }
 224                if (!stream_to_pack(state, &ctx, &already_hashed_to,
 225                                    fd, size, type, path, flags))
 226                        break;
 227                /*
 228                 * Writing this object to the current pack will make
 229                 * it too big; we need to truncate it, start a new
 230                 * pack, and write into it.
 231                 */
 232                if (!idx)
 233                        BUG("should not happen");
 234                hashfile_truncate(state->f, &checkpoint);
 235                state->offset = checkpoint.offset;
 236                finish_bulk_checkin(state);
 237                if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
 238                        return error("cannot seek back");
 239        }
 240        the_hash_algo->final_fn(result_oid->hash, &ctx);
 241        if (!idx)
 242                return 0;
 243
 244        idx->crc32 = crc32_end(state->f);
 245        if (already_written(state, result_oid)) {
 246                hashfile_truncate(state->f, &checkpoint);
 247                state->offset = checkpoint.offset;
 248                free(idx);
 249        } else {
 250                oidcpy(&idx->oid, result_oid);
 251                ALLOC_GROW(state->written,
 252                           state->nr_written + 1,
 253                           state->alloc_written);
 254                state->written[state->nr_written++] = idx;
 255        }
 256        return 0;
 257}
 258
 259int index_bulk_checkin(struct object_id *oid,
 260                       int fd, size_t size, enum object_type type,
 261                       const char *path, unsigned flags)
 262{
 263        int status = deflate_to_pack(&state, oid, fd, size, type,
 264                                     path, flags);
 265        if (!state.plugged)
 266                finish_bulk_checkin(&state);
 267        return status;
 268}
 269
 270void plug_bulk_checkin(void)
 271{
 272        state.plugged = 1;
 273}
 274
 275void unplug_bulk_checkin(void)
 276{
 277        state.plugged = 0;
 278        if (state.f)
 279                finish_bulk_checkin(&state);
 280}