bulk-checkin.con commit Merge branch 'jk/url-insteadof-config' (ec8455e)
   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
  10static struct bulk_checkin_state {
  11        unsigned plugged:1;
  12
  13        char *pack_tmp_name;
  14        struct sha1file *f;
  15        off_t offset;
  16        struct pack_idx_option pack_idx_opts;
  17
  18        struct pack_idx_entry **written;
  19        uint32_t alloc_written;
  20        uint32_t nr_written;
  21} state;
  22
  23static void finish_bulk_checkin(struct bulk_checkin_state *state)
  24{
  25        struct object_id oid;
  26        struct strbuf packname = STRBUF_INIT;
  27        int i;
  28
  29        if (!state->f)
  30                return;
  31
  32        if (state->nr_written == 0) {
  33                close(state->f->fd);
  34                unlink(state->pack_tmp_name);
  35                goto clear_exit;
  36        } else if (state->nr_written == 1) {
  37                sha1close(state->f, oid.hash, CSUM_FSYNC);
  38        } else {
  39                int fd = sha1close(state->f, oid.hash, 0);
  40                fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
  41                                         state->nr_written, oid.hash,
  42                                         state->offset);
  43                close(fd);
  44        }
  45
  46        strbuf_addf(&packname, "%s/pack/pack-", get_object_directory());
  47        finish_tmp_packfile(&packname, state->pack_tmp_name,
  48                            state->written, state->nr_written,
  49                            &state->pack_idx_opts, oid.hash);
  50        for (i = 0; i < state->nr_written; i++)
  51                free(state->written[i]);
  52
  53clear_exit:
  54        free(state->written);
  55        memset(state, 0, sizeof(*state));
  56
  57        strbuf_release(&packname);
  58        /* Make objects we just wrote available to ourselves */
  59        reprepare_packed_git();
  60}
  61
  62static int already_written(struct bulk_checkin_state *state, unsigned char sha1[])
  63{
  64        int i;
  65
  66        /* The object may already exist in the repository */
  67        if (has_sha1_file(sha1))
  68                return 1;
  69
  70        /* Might want to keep the list sorted */
  71        for (i = 0; i < state->nr_written; i++)
  72                if (!hashcmp(state->written[i]->oid.hash, sha1))
  73                        return 1;
  74
  75        /* This is a new object we need to keep */
  76        return 0;
  77}
  78
  79/*
  80 * Read the contents from fd for size bytes, streaming it to the
  81 * packfile in state while updating the hash in ctx. Signal a failure
  82 * by returning a negative value when the resulting pack would exceed
  83 * the pack size limit and this is not the first object in the pack,
  84 * so that the caller can discard what we wrote from the current pack
  85 * by truncating it and opening a new one. The caller will then call
  86 * us again after rewinding the input fd.
  87 *
  88 * The already_hashed_to pointer is kept untouched by the caller to
  89 * make sure we do not hash the same byte when we are called
  90 * again. This way, the caller does not have to checkpoint its hash
  91 * status before calling us just in case we ask it to call us again
  92 * with a new pack.
  93 */
  94static int stream_to_pack(struct bulk_checkin_state *state,
  95                          git_SHA_CTX *ctx, off_t *already_hashed_to,
  96                          int fd, size_t size, enum object_type type,
  97                          const char *path, unsigned flags)
  98{
  99        git_zstream s;
 100        unsigned char obuf[16384];
 101        unsigned hdrlen;
 102        int status = Z_OK;
 103        int write_object = (flags & HASH_WRITE_OBJECT);
 104        off_t offset = 0;
 105
 106        git_deflate_init(&s, pack_compression_level);
 107
 108        hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
 109        s.next_out = obuf + hdrlen;
 110        s.avail_out = sizeof(obuf) - hdrlen;
 111
 112        while (status != Z_STREAM_END) {
 113                unsigned char ibuf[16384];
 114
 115                if (size && !s.avail_in) {
 116                        ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
 117                        if (read_in_full(fd, ibuf, rsize) != rsize)
 118                                die("failed to read %d bytes from '%s'",
 119                                    (int)rsize, path);
 120                        offset += rsize;
 121                        if (*already_hashed_to < offset) {
 122                                size_t hsize = offset - *already_hashed_to;
 123                                if (rsize < hsize)
 124                                        hsize = rsize;
 125                                if (hsize)
 126                                        git_SHA1_Update(ctx, ibuf, hsize);
 127                                *already_hashed_to = offset;
 128                        }
 129                        s.next_in = ibuf;
 130                        s.avail_in = rsize;
 131                        size -= rsize;
 132                }
 133
 134                status = git_deflate(&s, size ? 0 : Z_FINISH);
 135
 136                if (!s.avail_out || status == Z_STREAM_END) {
 137                        if (write_object) {
 138                                size_t written = s.next_out - obuf;
 139
 140                                /* would we bust the size limit? */
 141                                if (state->nr_written &&
 142                                    pack_size_limit_cfg &&
 143                                    pack_size_limit_cfg < state->offset + written) {
 144                                        git_deflate_abort(&s);
 145                                        return -1;
 146                                }
 147
 148                                sha1write(state->f, obuf, written);
 149                                state->offset += written;
 150                        }
 151                        s.next_out = obuf;
 152                        s.avail_out = sizeof(obuf);
 153                }
 154
 155                switch (status) {
 156                case Z_OK:
 157                case Z_BUF_ERROR:
 158                case Z_STREAM_END:
 159                        continue;
 160                default:
 161                        die("unexpected deflate failure: %d", status);
 162                }
 163        }
 164        git_deflate_end(&s);
 165        return 0;
 166}
 167
 168/* Lazily create backing packfile for the state */
 169static void prepare_to_stream(struct bulk_checkin_state *state,
 170                              unsigned flags)
 171{
 172        if (!(flags & HASH_WRITE_OBJECT) || state->f)
 173                return;
 174
 175        state->f = create_tmp_packfile(&state->pack_tmp_name);
 176        reset_pack_idx_option(&state->pack_idx_opts);
 177
 178        /* Pretend we are going to write only one object */
 179        state->offset = write_pack_header(state->f, 1);
 180        if (!state->offset)
 181                die_errno("unable to write pack header");
 182}
 183
 184static int deflate_to_pack(struct bulk_checkin_state *state,
 185                           unsigned char result_sha1[],
 186                           int fd, size_t size,
 187                           enum object_type type, const char *path,
 188                           unsigned flags)
 189{
 190        off_t seekback, already_hashed_to;
 191        git_SHA_CTX ctx;
 192        unsigned char obuf[16384];
 193        unsigned header_len;
 194        struct sha1file_checkpoint checkpoint;
 195        struct pack_idx_entry *idx = NULL;
 196
 197        seekback = lseek(fd, 0, SEEK_CUR);
 198        if (seekback == (off_t) -1)
 199                return error("cannot find the current offset");
 200
 201        header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
 202                               typename(type), (uintmax_t)size) + 1;
 203        git_SHA1_Init(&ctx);
 204        git_SHA1_Update(&ctx, obuf, header_len);
 205
 206        /* Note: idx is non-NULL when we are writing */
 207        if ((flags & HASH_WRITE_OBJECT) != 0)
 208                idx = xcalloc(1, sizeof(*idx));
 209
 210        already_hashed_to = 0;
 211
 212        while (1) {
 213                prepare_to_stream(state, flags);
 214                if (idx) {
 215                        sha1file_checkpoint(state->f, &checkpoint);
 216                        idx->offset = state->offset;
 217                        crc32_begin(state->f);
 218                }
 219                if (!stream_to_pack(state, &ctx, &already_hashed_to,
 220                                    fd, size, type, path, flags))
 221                        break;
 222                /*
 223                 * Writing this object to the current pack will make
 224                 * it too big; we need to truncate it, start a new
 225                 * pack, and write into it.
 226                 */
 227                if (!idx)
 228                        die("BUG: should not happen");
 229                sha1file_truncate(state->f, &checkpoint);
 230                state->offset = checkpoint.offset;
 231                finish_bulk_checkin(state);
 232                if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
 233                        return error("cannot seek back");
 234        }
 235        git_SHA1_Final(result_sha1, &ctx);
 236        if (!idx)
 237                return 0;
 238
 239        idx->crc32 = crc32_end(state->f);
 240        if (already_written(state, result_sha1)) {
 241                sha1file_truncate(state->f, &checkpoint);
 242                state->offset = checkpoint.offset;
 243                free(idx);
 244        } else {
 245                hashcpy(idx->oid.hash, result_sha1);
 246                ALLOC_GROW(state->written,
 247                           state->nr_written + 1,
 248                           state->alloc_written);
 249                state->written[state->nr_written++] = idx;
 250        }
 251        return 0;
 252}
 253
 254int index_bulk_checkin(unsigned char *sha1,
 255                       int fd, size_t size, enum object_type type,
 256                       const char *path, unsigned flags)
 257{
 258        int status = deflate_to_pack(&state, sha1, fd, size, type,
 259                                     path, flags);
 260        if (!state.plugged)
 261                finish_bulk_checkin(&state);
 262        return status;
 263}
 264
 265void plug_bulk_checkin(void)
 266{
 267        state.plugged = 1;
 268}
 269
 270void unplug_bulk_checkin(void)
 271{
 272        state.plugged = 0;
 273        if (state.f)
 274                finish_bulk_checkin(&state);
 275}