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rust-rocksdb/src/lib.rs

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7.4 KiB

9 years ago
// Copyright 2014 Tyler Neely
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//! Rust wrapper for RocksDB.
//!
//! # Examples
//!
//! ```
//! use rocksdb::{DB, Options};
//! // NB: db is automatically closed at end of lifetime
//! let path = "_path_for_rocksdb_storage";
//! {
//! let db = DB::open_default(path).unwrap();
//! db.put(b"my key", b"my value");
//! match db.get(b"my key") {
//! Ok(Some(value)) => println!("retrieved value {}", value.to_utf8().unwrap()),
//! Ok(None) => println!("value not found"),
//! Err(e) => println!("operational problem encountered: {}", e),
//! }
//! db.delete(b"my key").unwrap();
//! }
//! let _ = DB::destroy(&Options::default(), path);
//! ```
//!
//! Opening a database and a single column family with custom options:
//!
//! ```
//! use rocksdb::{DB, ColumnFamilyDescriptor, Options};
//!
//! let path = "_path_for_rocksdb_storage_with_cfs";
//! let mut cf_opts = Options::default();
//! cf_opts.set_max_write_buffer_number(16);
//! let cf = ColumnFamilyDescriptor::new("cf1", cf_opts);
//!
//! let mut db_opts = Options::default();
//! db_opts.create_missing_column_families(true);
//! db_opts.create_if_missing(true);
//! {
//! let db = DB::open_cf_descriptors(&db_opts, path, vec![cf]).unwrap();
//! }
//! let _ = DB::destroy(&db_opts, path);
//! ```
//!
extern crate libc;
extern crate librocksdb_sys as ffi;
#[macro_use]
mod ffi_util;
pub mod backup;
pub mod checkpoint;
pub mod compaction_filter;
mod comparator;
mod db;
mod db_options;
pub mod merge_operator;
mod slice_transform;
pub use compaction_filter::Decision as CompactionDecision;
pub use db::{
DBCompactionStyle, DBCompressionType, DBIterator, DBRawIterator, DBRecoveryMode, DBVector,
Direction, IteratorMode, ReadOptions, Snapshot, WriteBatch,
};
pub use slice_transform::SliceTransform;
pub use merge_operator::MergeOperands;
use std::collections::BTreeMap;
use std::error;
use std::fmt;
use std::marker::PhantomData;
use std::path::PathBuf;
use std::sync::{Arc, RwLock};
/// A RocksDB database.
///
/// See crate level documentation for a simple usage example.
pub struct DB {
inner: *mut ffi::rocksdb_t,
cfs: Arc<RwLock<BTreeMap<String, *mut ffi::rocksdb_column_family_handle_t>>>,
path: PathBuf,
}
/// A descriptor for a RocksDB column family.
///
/// A description of the column family, containing the name and `Options`.
pub struct ColumnFamilyDescriptor {
name: String,
options: Options,
}
/// A simple wrapper round a string, used for errors reported from
/// ffi calls.
#[derive(Debug, Clone, PartialEq)]
pub struct Error {
message: String,
}
impl Error {
fn new(message: String) -> Error {
6 years ago
Error { message }
}
pub fn to_string(self) -> String {
self.into()
}
}
impl AsRef<str> for Error {
fn as_ref(&self) -> &str {
&self.message
}
}
impl From<Error> for String {
fn from(e: Error) -> String {
e.message
}
}
impl error::Error for Error {
fn description(&self) -> &str {
&self.message
}
}
impl fmt::Display for Error {
fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
self.message.fmt(formatter)
}
}
/// For configuring block-based file storage.
pub struct BlockBasedOptions {
inner: *mut ffi::rocksdb_block_based_table_options_t,
}
/// Used by BlockBasedOptions::set_index_type.
pub enum BlockBasedIndexType {
/// A space efficient index block that is optimized for
/// binary-search-based index.
BinarySearch,
/// The hash index, if enabled, will perform a hash lookup if
/// a prefix extractor has been provided through Options::set_prefix_extractor.
HashSearch,
/// A two-level index implementation. Both levels are binary search indexes.
TwoLevelIndexSearch,
}
/// Defines the underlying memtable implementation.
/// See https://github.com/facebook/rocksdb/wiki/MemTable for more information.
pub enum MemtableFactory {
Vector,
HashSkipList {
bucket_count: usize,
height: i32,
branching_factor: i32,
},
HashLinkList {
bucket_count: usize,
},
}
/// Used with DBOptions::set_plain_table_factory.
/// See https://github.com/facebook/rocksdb/wiki/PlainTable-Format.
///
/// Defaults:
/// user_key_length: 0 (variable length)
/// bloom_bits_per_key: 10
/// hash_table_ratio: 0.75
/// index_sparseness: 16
pub struct PlainTableFactoryOptions {
pub user_key_length: u32,
pub bloom_bits_per_key: i32,
pub hash_table_ratio: f64,
pub index_sparseness: usize,
}
/// Database-wide options around performance and behavior.
///
/// Please read [the official tuning guide](https://github.com/facebook/rocksdb/wiki/RocksDB-Tuning-Guide), and most importantly, measure performance under realistic workloads with realistic hardware.
///
/// # Examples
///
/// ```
/// use rocksdb::{Options, DB};
/// use rocksdb::DBCompactionStyle;
///
/// fn badly_tuned_for_somebody_elses_disk() -> DB {
/// let path = "path/for/rocksdb/storageX";
/// let mut opts = Options::default();
/// opts.create_if_missing(true);
/// opts.set_max_open_files(10000);
/// opts.set_use_fsync(false);
/// opts.set_bytes_per_sync(8388608);
/// opts.optimize_for_point_lookup(1024);
/// opts.set_table_cache_num_shard_bits(6);
/// opts.set_max_write_buffer_number(32);
/// opts.set_write_buffer_size(536870912);
/// opts.set_target_file_size_base(1073741824);
/// opts.set_min_write_buffer_number_to_merge(4);
/// opts.set_level_zero_stop_writes_trigger(2000);
/// opts.set_level_zero_slowdown_writes_trigger(0);
/// opts.set_compaction_style(DBCompactionStyle::Universal);
/// opts.set_max_background_compactions(4);
/// opts.set_max_background_flushes(4);
/// opts.set_disable_auto_compactions(true);
///
/// DB::open(&opts, path).unwrap()
/// }
/// ```
pub struct Options {
inner: *mut ffi::rocksdb_options_t,
}
/// Optionally disable WAL or sync for this write.
///
/// # Examples
///
/// Making an unsafe write of a batch:
///
/// ```
/// use rocksdb::{DB, Options, WriteBatch, WriteOptions};
///
/// let path = "_path_for_rocksdb_storageY";
/// {
/// let db = DB::open_default(path).unwrap();
/// let mut batch = WriteBatch::default();
/// batch.put(b"my key", b"my value");
/// batch.put(b"key2", b"value2");
/// batch.put(b"key3", b"value3");
///
/// let mut write_options = WriteOptions::default();
/// write_options.set_sync(false);
/// write_options.disable_wal(true);
///
/// db.write_opt(batch, &write_options);
/// }
/// let _ = DB::destroy(&Options::default(), path);
/// ```
pub struct WriteOptions {
inner: *mut ffi::rocksdb_writeoptions_t,
}
/// An opaque type used to represent a column family. Returned from some functions, and used
/// in others
#[derive(Copy, Clone)]
pub struct ColumnFamily<'a> {
inner: *mut ffi::rocksdb_column_family_handle_t,
db: PhantomData<&'a DB>,
}
unsafe impl<'a> Send for ColumnFamily<'a> {}