bulk-checkin.c

   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 #include "object-store.h"
  12
  13 static int bulk_checkin_plugged;
  14
  15 static struct bulk_checkin_packfile {
  16         char *pack_tmp_name;
  17         struct hashfile *f;
  18         off_t offset;
  19         struct pack_idx_option pack_idx_opts;
  20
  21         struct pack_idx_entry **written;
  22         uint32_t alloc_written;
  23         uint32_t nr_written;
  24 } bulk_checkin_packfile;
  25
  26 static void finish_tmp_packfile(struct strbuf *basename,
  27                                 const char *pack_tmp_name,
  28                                 struct pack_idx_entry **written_list,
  29                                 uint32_t nr_written,
  30                                 struct pack_idx_option *pack_idx_opts,
  31                                 unsigned char hash[])
  32 {
  33         char *idx_tmp_name = NULL;
  34
  35         stage_tmp_packfiles(basename, pack_tmp_name, written_list, nr_written,
  36                             pack_idx_opts, hash, &idx_tmp_name);
  37         rename_tmp_packfile_idx(basename, &idx_tmp_name);
  38
  39         free(idx_tmp_name);
  40 }
  41
  42 static void flush_bulk_checkin_packfile(struct bulk_checkin_packfile *state)
  43 {
  44         unsigned char hash[GIT_MAX_RAWSZ];
  45         struct strbuf packname = STRBUF_INIT;
  46         int i;
  47
  48         if (!state->f)
  49                 return;
  50
  51         if (state->nr_written == 0) {
  52                 close(state->f->fd);
  53                 unlink(state->pack_tmp_name);
  54                 goto clear_exit;
  55         } else if (state->nr_written == 1) {
  56                 finalize_hashfile(state->f, hash, FSYNC_COMPONENT_PACK,
  57                                   CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
  58         } else {
  59                 int fd = finalize_hashfile(state->f, hash, FSYNC_COMPONENT_PACK, 0);
  60                 fixup_pack_header_footer(fd, hash, state->pack_tmp_name,
  61                                          state->nr_written, hash,
  62                                          state->offset);
  63                 close(fd);
  64         }
  65
  66         strbuf_addf(&packname, "%s/pack/pack-%s.", get_object_directory(),
  67                     hash_to_hex(hash));
  68         finish_tmp_packfile(&packname, state->pack_tmp_name,
  69                             state->written, state->nr_written,
  70                             &state->pack_idx_opts, hash);
  71         for (i = 0; i < state->nr_written; i++)
  72                 free(state->written[i]);
  73
  74 clear_exit:
  75         free(state->written);
  76         memset(state, 0, sizeof(*state));
  77
  78         strbuf_release(&packname);
  79         /* Make objects we just wrote available to ourselves */
  80         reprepare_packed_git(the_repository);
  81 }
  82
  83 static int already_written(struct bulk_checkin_packfile *state, struct object_id *oid)
  84 {
  85         int i;
  86
  87         /* The object may already exist in the repository */
  88         if (has_object_file(oid))
  89                 return 1;
  90
  91         /* Might want to keep the list sorted */
  92         for (i = 0; i < state->nr_written; i++)
  93                 if (oideq(&state->written[i]->oid, oid))
  94                         return 1;
  95
  96         /* This is a new object we need to keep */
  97         return 0;
  98 }
  99
 100 /*
 101  * Read the contents from fd for size bytes, streaming it to the
 102  * packfile in state while updating the hash in ctx. Signal a failure
 103  * by returning a negative value when the resulting pack would exceed
 104  * the pack size limit and this is not the first object in the pack,
 105  * so that the caller can discard what we wrote from the current pack
 106  * by truncating it and opening a new one. The caller will then call
 107  * us again after rewinding the input fd.
 108  *
 109  * The already_hashed_to pointer is kept untouched by the caller to
 110  * make sure we do not hash the same byte when we are called
 111  * again. This way, the caller does not have to checkpoint its hash
 112  * status before calling us just in case we ask it to call us again
 113  * with a new pack.
 114  */
 115 static int stream_to_pack(struct bulk_checkin_packfile *state,
 116                           git_hash_ctx *ctx, off_t *already_hashed_to,
 117                           int fd, size_t size, enum object_type type,
 118                           const char *path, unsigned flags)
 119 {
 120         git_zstream s;
 121         unsigned char ibuf[16384];
 122         unsigned char obuf[16384];
 123         unsigned hdrlen;
 124         int status = Z_OK;
 125         int write_object = (flags & HASH_WRITE_OBJECT);
 126         off_t offset = 0;
 127
 128         git_deflate_init(&s, pack_compression_level);
 129
 130         hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), type, size);
 131         s.next_out = obuf + hdrlen;
 132         s.avail_out = sizeof(obuf) - hdrlen;
 133
 134         while (status != Z_STREAM_END) {
 135                 if (size && !s.avail_in) {
 136                         ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
 137                         ssize_t read_result = read_in_full(fd, ibuf, rsize);
 138                         if (read_result < 0)
 139                                 die_errno("failed to read from '%s'", path);
 140                         if (read_result != rsize)
 141                                 die("failed to read %d bytes from '%s'",
 142                                     (int)rsize, path);
 143                         offset += rsize;
 144                         if (*already_hashed_to < offset) {
 145                                 size_t hsize = offset - *already_hashed_to;
 146                                 if (rsize < hsize)
 147                                         hsize = rsize;
 148                                 if (hsize)
 149                                         the_hash_algo->update_fn(ctx, ibuf, hsize);
 150                                 *already_hashed_to = offset;
 151                         }
 152                         s.next_in = ibuf;
 153                         s.avail_in = rsize;
 154                         size -= rsize;
 155                 }
 156
 157                 status = git_deflate(&s, size ? 0 : Z_FINISH);
 158
 159                 if (!s.avail_out || status == Z_STREAM_END) {
 160                         if (write_object) {
 161                                 size_t written = s.next_out - obuf;
 162
 163                                 /* would we bust the size limit? */
 164                                 if (state->nr_written &&
 165                                     pack_size_limit_cfg &&
 166                                     pack_size_limit_cfg < state->offset + written) {
 167                                         git_deflate_abort(&s);
 168                                         return -1;
 169                                 }
 170
 171                                 hashwrite(state->f, obuf, written);
 172                                 state->offset += written;
 173                         }
 174                         s.next_out = obuf;
 175                         s.avail_out = sizeof(obuf);
 176                 }
 177
 178                 switch (status) {
 179                 case Z_OK:
 180                 case Z_BUF_ERROR:
 181                 case Z_STREAM_END:
 182                         continue;
 183                 default:
 184                         die("unexpected deflate failure: %d", status);
 185                 }
 186         }
 187         git_deflate_end(&s);
 188         return 0;
 189 }
 190
 191 /* Lazily create backing packfile for the state */
 192 static void prepare_to_stream(struct bulk_checkin_packfile *state,
 193                               unsigned flags)
 194 {
 195         if (!(flags & HASH_WRITE_OBJECT) || state->f)
 196                 return;
 197
 198         state->f = create_tmp_packfile(&state->pack_tmp_name);
 199         reset_pack_idx_option(&state->pack_idx_opts);
 200
 201         /* Pretend we are going to write only one object */
 202         state->offset = write_pack_header(state->f, 1);
 203         if (!state->offset)
 204                 die_errno("unable to write pack header");
 205 }
 206
 207 static int deflate_to_pack(struct bulk_checkin_packfile *state,
 208                            struct object_id *result_oid,
 209                            int fd, size_t size,
 210                            enum object_type type, const char *path,
 211                            unsigned flags)
 212 {
 213         off_t seekback, already_hashed_to;
 214         git_hash_ctx ctx;
 215         unsigned char obuf[16384];
 216         unsigned header_len;
 217         struct hashfile_checkpoint checkpoint = {0};
 218         struct pack_idx_entry *idx = NULL;
 219
 220         seekback = lseek(fd, 0, SEEK_CUR);
 221         if (seekback == (off_t) -1)
 222                 return error("cannot find the current offset");
 223
 224         header_len = xsnprintf((char *)obuf, sizeof(obuf), "%s %" PRIuMAX,
 225                                type_name(type), (uintmax_t)size) + 1;
 226         the_hash_algo->init_fn(&ctx);
 227         the_hash_algo->update_fn(&ctx, obuf, header_len);
 228
 229         /* Note: idx is non-NULL when we are writing */
 230         if ((flags & HASH_WRITE_OBJECT) != 0)
 231                 CALLOC_ARRAY(idx, 1);
 232
 233         already_hashed_to = 0;
 234
 235         while (1) {
 236                 prepare_to_stream(state, flags);
 237                 if (idx) {
 238                         hashfile_checkpoint(state->f, &checkpoint);
 239                         idx->offset = state->offset;
 240                         crc32_begin(state->f);
 241                 }
 242                 if (!stream_to_pack(state, &ctx, &already_hashed_to,
 243                                     fd, size, type, path, flags))
 244                         break;
 245                 /*
 246                  * Writing this object to the current pack will make
 247                  * it too big; we need to truncate it, start a new
 248                  * pack, and write into it.
 249                  */
 250                 if (!idx)
 251                         BUG("should not happen");
 252                 hashfile_truncate(state->f, &checkpoint);
 253                 state->offset = checkpoint.offset;
 254                 flush_bulk_checkin_packfile(state);
 255                 if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
 256                         return error("cannot seek back");
 257         }
 258         the_hash_algo->final_oid_fn(result_oid, &ctx);
 259         if (!idx)
 260                 return 0;
 261
 262         idx->crc32 = crc32_end(state->f);
 263         if (already_written(state, result_oid)) {
 264                 hashfile_truncate(state->f, &checkpoint);
 265                 state->offset = checkpoint.offset;
 266                 free(idx);
 267         } else {
 268                 oidcpy(&idx->oid, result_oid);
 269                 ALLOC_GROW(state->written,
 270                            state->nr_written + 1,
 271                            state->alloc_written);
 272                 state->written[state->nr_written++] = idx;
 273         }
 274         return 0;
 275 }
 276
 277 int index_bulk_checkin(struct object_id *oid,
 278                        int fd, size_t size, enum object_type type,
 279                        const char *path, unsigned flags)
 280 {
 281         int status = deflate_to_pack(&bulk_checkin_packfile, oid, fd, size, type,
 282                                      path, flags);
 283         if (!bulk_checkin_plugged)
 284                 flush_bulk_checkin_packfile(&bulk_checkin_packfile);
 285         return status;
 286 }
 287
 288 void plug_bulk_checkin(void)
 289 {
 290         assert(!bulk_checkin_plugged);
 291         bulk_checkin_plugged = 1;
 292 }
 293
 294 void unplug_bulk_checkin(void)
 295 {
 296         assert(bulk_checkin_plugged);
 297         bulk_checkin_plugged = 0;
 298         flush_bulk_checkin_packfile(&bulk_checkin_packfile);
 299 }