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Diffstat (limited to 'reftable/reftable-stack.h')
| -rw-r--r-- | reftable/reftable-stack.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/reftable/reftable-stack.h b/reftable/reftable-stack.h new file mode 100644 index 0000000000..1b602dda58 --- /dev/null +++ b/reftable/reftable-stack.h @@ -0,0 +1,128 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#ifndef REFTABLE_STACK_H +#define REFTABLE_STACK_H + +#include "reftable-writer.h" + +/* + * The stack presents an interface to a mutable sequence of reftables. + + * A stack can be mutated by pushing a table to the top of the stack. + + * The reftable_stack automatically compacts files on disk to ensure good + * amortized performance. + * + * For windows and other platforms that cannot have open files as rename + * destinations, concurrent access from multiple processes needs the rand() + * random seed to be randomized. + */ +struct reftable_stack; + +/* open a new reftable stack. The tables along with the table list will be + * stored in 'dir'. Typically, this should be .git/reftables. + */ +int reftable_new_stack(struct reftable_stack **dest, const char *dir, + struct reftable_write_options config); + +/* returns the update_index at which a next table should be written. */ +uint64_t reftable_stack_next_update_index(struct reftable_stack *st); + +/* holds a transaction to add tables at the top of a stack. */ +struct reftable_addition; + +/* + * returns a new transaction to add reftables to the given stack. As a side + * effect, the ref database is locked. + */ +int reftable_stack_new_addition(struct reftable_addition **dest, + struct reftable_stack *st); + +/* Adds a reftable to transaction. */ +int reftable_addition_add(struct reftable_addition *add, + int (*write_table)(struct reftable_writer *wr, + void *arg), + void *arg); + +/* Commits the transaction, releasing the lock. After calling this, + * reftable_addition_destroy should still be called. + */ +int reftable_addition_commit(struct reftable_addition *add); + +/* Release all non-committed data from the transaction, and deallocate the + * transaction. Releases the lock if held. */ +void reftable_addition_destroy(struct reftable_addition *add); + +/* add a new table to the stack. The write_table function must call + * reftable_writer_set_limits, add refs and return an error value. */ +int reftable_stack_add(struct reftable_stack *st, + int (*write_table)(struct reftable_writer *wr, + void *write_arg), + void *write_arg); + +/* returns the merged_table for seeking. This table is valid until the + * next write or reload, and should not be closed or deleted. + */ +struct reftable_merged_table * +reftable_stack_merged_table(struct reftable_stack *st); + +/* frees all resources associated with the stack. */ +void reftable_stack_destroy(struct reftable_stack *st); + +/* Reloads the stack if necessary. This is very cheap to run if the stack was up + * to date */ +int reftable_stack_reload(struct reftable_stack *st); + +/* Policy for expiring reflog entries. */ +struct reftable_log_expiry_config { + /* Drop entries older than this timestamp */ + uint64_t time; + + /* Drop older entries */ + uint64_t min_update_index; +}; + +/* compacts all reftables into a giant table. Expire reflog entries if config is + * non-NULL */ +int reftable_stack_compact_all(struct reftable_stack *st, + struct reftable_log_expiry_config *config); + +/* heuristically compact unbalanced table stack. */ +int reftable_stack_auto_compact(struct reftable_stack *st); + +/* delete stale .ref tables. */ +int reftable_stack_clean(struct reftable_stack *st); + +/* convenience function to read a single ref. Returns < 0 for error, 0 for + * success, and 1 if ref not found. */ +int reftable_stack_read_ref(struct reftable_stack *st, const char *refname, + struct reftable_ref_record *ref); + +/* convenience function to read a single log. Returns < 0 for error, 0 for + * success, and 1 if ref not found. */ +int reftable_stack_read_log(struct reftable_stack *st, const char *refname, + struct reftable_log_record *log); + +/* statistics on past compactions. */ +struct reftable_compaction_stats { + uint64_t bytes; /* total number of bytes written */ + uint64_t entries_written; /* total number of entries written, including + failures. */ + int attempts; /* how often we tried to compact */ + int failures; /* failures happen on concurrent updates */ +}; + +/* return statistics for compaction up till now. */ +struct reftable_compaction_stats * +reftable_stack_compaction_stats(struct reftable_stack *st); + +/* print the entire stack represented by the directory */ +int reftable_stack_print_directory(const char *stackdir, uint32_t hash_id); + +#endif |