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1df18a1c9a
While the reffiles backend honors configured fsync settings, the reftable backend does not. Address this by fsyncing reftable files using the write-or-die api's fsync_component() in two places: when we add additional entries into the table, and when we close the reftable writer. This commits adds a flush function pointer as a new member of reftable_writer because we are not sure that the first argument to the *write function pointer always contains a file descriptor. In the case of strbuf_add_void, the first argument is a buffer. This way, we can pass in a corresponding flush function that knows how to flush depending on which writer is being used. This patch does not contain tests as they will need to wait for another patch to start to exercise the reftable backend. At that point, the tests will be added to observe that fsyncs are happening when the reftable is in use. Signed-off-by: John Cai <johncai86@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
153 lines
4.7 KiB
C
153 lines
4.7 KiB
C
/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#ifndef REFTABLE_WRITER_H
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#define REFTABLE_WRITER_H
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#include "reftable-record.h"
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#include <stdint.h>
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#include <unistd.h> /* ssize_t */
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/* Writing single reftables */
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/* reftable_write_options sets options for writing a single reftable. */
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struct reftable_write_options {
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/* boolean: do not pad out blocks to block size. */
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unsigned unpadded : 1;
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/* the blocksize. Should be less than 2^24. */
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uint32_t block_size;
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/* boolean: do not generate a SHA1 => ref index. */
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unsigned skip_index_objects : 1;
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/* how often to write complete keys in each block. */
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int restart_interval;
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/* 4-byte identifier ("sha1", "s256") of the hash.
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* Defaults to SHA1 if unset
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*/
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uint32_t hash_id;
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/* Default mode for creating files. If unset, use 0666 (+umask) */
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unsigned int default_permissions;
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/* boolean: do not check ref names for validity or dir/file conflicts.
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*/
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unsigned skip_name_check : 1;
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/* boolean: copy log messages exactly. If unset, check that the message
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* is a single line, and add '\n' if missing.
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*/
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unsigned exact_log_message : 1;
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};
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/* reftable_block_stats holds statistics for a single block type */
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struct reftable_block_stats {
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/* total number of entries written */
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int entries;
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/* total number of key restarts */
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int restarts;
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/* total number of blocks */
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int blocks;
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/* total number of index blocks */
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int index_blocks;
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/* depth of the index */
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int max_index_level;
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/* offset of the first block for this type */
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uint64_t offset;
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/* offset of the top level index block for this type, or 0 if not
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* present */
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uint64_t index_offset;
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};
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/* stats holds overall statistics for a single reftable */
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struct reftable_stats {
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/* total number of blocks written. */
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int blocks;
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/* stats for ref data */
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struct reftable_block_stats ref_stats;
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/* stats for the SHA1 to ref map. */
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struct reftable_block_stats obj_stats;
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/* stats for index blocks */
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struct reftable_block_stats idx_stats;
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/* stats for log blocks */
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struct reftable_block_stats log_stats;
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/* disambiguation length of shortened object IDs. */
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int object_id_len;
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};
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/* reftable_new_writer creates a new writer */
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struct reftable_writer *
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reftable_new_writer(ssize_t (*writer_func)(void *, const void *, size_t),
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int (*flush_func)(void *),
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void *writer_arg, struct reftable_write_options *opts);
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/* Set the range of update indices for the records we will add. When writing a
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table into a stack, the min should be at least
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reftable_stack_next_update_index(), or REFTABLE_API_ERROR is returned.
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For transactional updates to a stack, typically min==max, and the
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update_index can be obtained by inspeciting the stack. When converting an
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existing ref database into a single reftable, this would be a range of
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update-index timestamps.
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*/
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void reftable_writer_set_limits(struct reftable_writer *w, uint64_t min,
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uint64_t max);
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/*
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Add a reftable_ref_record. The record should have names that come after
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already added records.
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The update_index must be within the limits set by
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reftable_writer_set_limits(), or REFTABLE_API_ERROR is returned. It is an
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REFTABLE_API_ERROR error to write a ref record after a log record.
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*/
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int reftable_writer_add_ref(struct reftable_writer *w,
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struct reftable_ref_record *ref);
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/*
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Convenience function to add multiple reftable_ref_records; the function sorts
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the records before adding them, reordering the records array passed in.
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*/
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int reftable_writer_add_refs(struct reftable_writer *w,
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struct reftable_ref_record *refs, int n);
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/*
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adds reftable_log_records. Log records are keyed by (refname, decreasing
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update_index). The key for the record added must come after the already added
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log records.
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*/
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int reftable_writer_add_log(struct reftable_writer *w,
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struct reftable_log_record *log);
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/*
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Convenience function to add multiple reftable_log_records; the function sorts
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the records before adding them, reordering records array passed in.
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*/
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int reftable_writer_add_logs(struct reftable_writer *w,
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struct reftable_log_record *logs, int n);
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/* reftable_writer_close finalizes the reftable. The writer is retained so
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* statistics can be inspected. */
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int reftable_writer_close(struct reftable_writer *w);
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/* writer_stats returns the statistics on the reftable being written.
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This struct becomes invalid when the writer is freed.
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*/
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const struct reftable_stats *reftable_writer_stats(struct reftable_writer *w);
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/* reftable_writer_free deallocates memory for the writer */
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void reftable_writer_free(struct reftable_writer *w);
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#endif
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