diff options
Diffstat (limited to 'reftable/writer.c')
-rw-r--r-- | reftable/writer.c | 137 |
1 files changed, 88 insertions, 49 deletions
diff --git a/reftable/writer.c b/reftable/writer.c index 1d9ff0fbfa..10eccaaa07 100644 --- a/reftable/writer.c +++ b/reftable/writer.c @@ -109,7 +109,7 @@ static void writer_reinit_block_writer(struct reftable_writer *w, uint8_t typ) block_start = header_size(writer_version(w)); } - strbuf_release(&w->last_key); + strbuf_reset(&w->last_key); block_writer_init(&w->block_writer_data, typ, w->block, w->opts.block_size, block_start, hash_size(w->opts.hash_id)); @@ -149,11 +149,21 @@ void reftable_writer_set_limits(struct reftable_writer *w, uint64_t min, w->max_update_index = max; } +static void writer_release(struct reftable_writer *w) +{ + if (w) { + reftable_free(w->block); + w->block = NULL; + block_writer_release(&w->block_writer_data); + w->block_writer = NULL; + writer_clear_index(w); + strbuf_release(&w->last_key); + } +} + void reftable_writer_free(struct reftable_writer *w) { - if (!w) - return; - reftable_free(w->block); + writer_release(w); reftable_free(w); } @@ -209,7 +219,8 @@ static int writer_add_record(struct reftable_writer *w, struct reftable_record *rec) { struct strbuf key = STRBUF_INIT; - int err = -1; + int err; + reftable_record_key(rec, &key); if (strbuf_cmp(&w->last_key, &key) >= 0) { err = REFTABLE_API_ERROR; @@ -218,27 +229,42 @@ static int writer_add_record(struct reftable_writer *w, strbuf_reset(&w->last_key); strbuf_addbuf(&w->last_key, &key); - if (!w->block_writer) { + if (!w->block_writer) writer_reinit_block_writer(w, reftable_record_type(rec)); - } - assert(block_writer_type(w->block_writer) == reftable_record_type(rec)); + if (block_writer_type(w->block_writer) != reftable_record_type(rec)) + BUG("record of type %d added to writer of type %d", + reftable_record_type(rec), block_writer_type(w->block_writer)); - if (block_writer_add(w->block_writer, rec) == 0) { + /* + * Try to add the record to the writer. If this succeeds then we're + * done. Otherwise the block writer may have hit the block size limit + * and needs to be flushed. + */ + if (!block_writer_add(w->block_writer, rec)) { err = 0; goto done; } + /* + * The current block is full, so we need to flush and reinitialize the + * writer to start writing the next block. + */ err = writer_flush_block(w); - if (err < 0) { + if (err < 0) goto done; - } - writer_reinit_block_writer(w, reftable_record_type(rec)); + + /* + * Try to add the record to the writer again. If this still fails then + * the record does not fit into the block size. + * + * TODO: it would be great to have `block_writer_add()` return proper + * error codes so that we don't have to second-guess the failure + * mode here. + */ err = block_writer_add(w->block_writer, rec); - if (err == -1) { - /* we are writing into memory, so an error can only mean it - * doesn't fit. */ + if (err) { err = REFTABLE_ENTRY_TOO_BIG_ERROR; goto done; } @@ -452,7 +478,7 @@ static int writer_finish_section(struct reftable_writer *w) bstats->max_index_level = max_level; /* Reinit lastKey, as the next section can start with any key. */ - w->last_key.len = 0; + strbuf_reset(&w->last_key); return 0; } @@ -627,74 +653,87 @@ int reftable_writer_close(struct reftable_writer *w) } done: - /* free up memory. */ - block_writer_release(&w->block_writer_data); - writer_clear_index(w); - strbuf_release(&w->last_key); + writer_release(w); return err; } static void writer_clear_index(struct reftable_writer *w) { - for (size_t i = 0; i < w->index_len; i++) + for (size_t i = 0; w->index && i < w->index_len; i++) strbuf_release(&w->index[i].last_key); FREE_AND_NULL(w->index); w->index_len = 0; w->index_cap = 0; } -static const int debug = 0; - static int writer_flush_nonempty_block(struct reftable_writer *w) { + struct reftable_index_record index_record = { + .last_key = STRBUF_INIT, + }; uint8_t typ = block_writer_type(w->block_writer); - struct reftable_block_stats *bstats = - writer_reftable_block_stats(w, typ); - uint64_t block_typ_off = (bstats->blocks == 0) ? w->next : 0; - int raw_bytes = block_writer_finish(w->block_writer); - int padding = 0; - int err = 0; - struct reftable_index_record ir = { .last_key = STRBUF_INIT }; + struct reftable_block_stats *bstats; + int raw_bytes, padding = 0, err; + uint64_t block_typ_off; + + /* + * Finish the current block. This will cause the block writer to emit + * restart points and potentially compress records in case we are + * writing a log block. + * + * Note that this is still happening in memory. + */ + raw_bytes = block_writer_finish(w->block_writer); if (raw_bytes < 0) return raw_bytes; - if (!w->opts.unpadded && typ != BLOCK_TYPE_LOG) { + /* + * By default, all records except for log records are padded to the + * block size. + */ + if (!w->opts.unpadded && typ != BLOCK_TYPE_LOG) padding = w->opts.block_size - raw_bytes; - } - if (block_typ_off > 0) { + bstats = writer_reftable_block_stats(w, typ); + block_typ_off = (bstats->blocks == 0) ? w->next : 0; + if (block_typ_off > 0) bstats->offset = block_typ_off; - } - bstats->entries += w->block_writer->entries; bstats->restarts += w->block_writer->restart_len; bstats->blocks++; w->stats.blocks++; - if (debug) { - fprintf(stderr, "block %c off %" PRIu64 " sz %d (%d)\n", typ, - w->next, raw_bytes, - get_be24(w->block + w->block_writer->header_off + 1)); - } - - if (w->next == 0) { + /* + * If this is the first block we're writing to the table then we need + * to also write the reftable header. + */ + if (!w->next) writer_write_header(w, w->block); - } err = padded_write(w, w->block, raw_bytes, padding); if (err < 0) return err; + /* + * Add an index record for every block that we're writing. If we end up + * having more than a threshold of index records we will end up writing + * an index section in `writer_finish_section()`. Each index record + * contains the last record key of the block it is indexing as well as + * the offset of that block. + * + * Note that this also applies when flushing index blocks, in which + * case we will end up with a multi-level index. + */ REFTABLE_ALLOC_GROW(w->index, w->index_len + 1, w->index_cap); - - ir.offset = w->next; - strbuf_reset(&ir.last_key); - strbuf_addbuf(&ir.last_key, &w->block_writer->last_key); - w->index[w->index_len] = ir; - + index_record.offset = w->next; + strbuf_reset(&index_record.last_key); + strbuf_addbuf(&index_record.last_key, &w->block_writer->last_key); + w->index[w->index_len] = index_record; w->index_len++; + w->next += padding + raw_bytes; w->block_writer = NULL; + return 0; } |