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// Copyright 2018-2019 Mozilla
//
// 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
// 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.
use std::{
fmt::{Debug, Display},
path::{Path, PathBuf},
};
use crate::{
backend::common::{DatabaseFlags, EnvironmentFlags, RecoveryStrategy, WriteFlags},
error::StoreError,
};
pub trait BackendError: Debug + Display + Into<StoreError> {}
pub trait BackendDatabase: Debug + Eq + PartialEq + Copy + Clone {}
pub trait BackendFlags: Debug + Eq + PartialEq + Copy + Clone + Default {
fn empty() -> Self;
}
pub trait BackendEnvironmentFlags: BackendFlags {
fn set(&mut self, flag: EnvironmentFlags, value: bool);
}
pub trait BackendDatabaseFlags: BackendFlags {
fn set(&mut self, flag: DatabaseFlags, value: bool);
}
pub trait BackendWriteFlags: BackendFlags {
fn set(&mut self, flag: WriteFlags, value: bool);
}
pub trait BackendStat {
fn page_size(&self) -> usize;
fn depth(&self) -> usize;
fn branch_pages(&self) -> usize;
fn leaf_pages(&self) -> usize;
fn overflow_pages(&self) -> usize;
fn entries(&self) -> usize;
}
pub trait BackendInfo {
fn map_size(&self) -> usize;
fn last_pgno(&self) -> usize;
fn last_txnid(&self) -> usize;
fn max_readers(&self) -> usize;
fn num_readers(&self) -> usize;
}
pub trait BackendEnvironmentBuilder<'b>: Debug + Eq + PartialEq + Copy + Clone {
type Error: BackendError;
type Environment: BackendEnvironment<'b>;
type Flags: BackendEnvironmentFlags;
fn new() -> Self;
fn set_flags<T>(&mut self, flags: T) -> &mut Self
where
T: Into<Self::Flags>;
fn set_max_dbs(&mut self, max_dbs: u32) -> &mut Self;
fn set_max_readers(&mut self, max_readers: u32) -> &mut Self;
fn set_map_size(&mut self, size: usize) -> &mut Self;
fn set_make_dir_if_needed(&mut self, make_dir_if_needed: bool) -> &mut Self;
/// Set the corruption recovery strategy. See [`RecoveryStrategy`] for details.
fn set_corruption_recovery_strategy(&mut self, strategy: RecoveryStrategy) -> &mut Self;
fn open(&self, path: &Path) -> Result<Self::Environment, Self::Error>;
}
pub trait BackendEnvironment<'e>: Debug {
type Error: BackendError;
type Database: BackendDatabase;
type Flags: BackendDatabaseFlags;
type Stat: BackendStat;
type Info: BackendInfo;
type RoTransaction: BackendRoCursorTransaction<'e, Database = Self::Database>;
type RwTransaction: BackendRwCursorTransaction<'e, Database = Self::Database>;
fn get_dbs(&self) -> Result<Vec<Option<String>>, Self::Error>;
fn open_db(&self, name: Option<&str>) -> Result<Self::Database, Self::Error>;
fn create_db(
&self,
name: Option<&str>,
flags: Self::Flags,
) -> Result<Self::Database, Self::Error>;
fn begin_ro_txn(&'e self) -> Result<Self::RoTransaction, Self::Error>;
fn begin_rw_txn(&'e self) -> Result<Self::RwTransaction, Self::Error>;
fn sync(&self, force: bool) -> Result<(), Self::Error>;
fn stat(&self) -> Result<Self::Stat, Self::Error>;
fn info(&self) -> Result<Self::Info, Self::Error>;
fn freelist(&self) -> Result<usize, Self::Error>;
fn load_ratio(&self) -> Result<Option<f32>, Self::Error>;
fn set_map_size(&self, size: usize) -> Result<(), Self::Error>;
fn get_files_on_disk(&self) -> Vec<PathBuf>;
}
pub trait BackendRoTransaction: Debug {
type Error: BackendError;
type Database: BackendDatabase;
fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error>;
fn abort(self);
}
pub trait BackendRwTransaction: Debug {
type Error: BackendError;
type Database: BackendDatabase;
type Flags: BackendWriteFlags;
fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error>;
fn put(
&mut self,
db: &Self::Database,
key: &[u8],
value: &[u8],
flags: Self::Flags,
) -> Result<(), Self::Error>;
#[cfg(not(feature = "db-dup-sort"))]
fn del(&mut self, db: &Self::Database, key: &[u8]) -> Result<(), Self::Error>;
#[cfg(feature = "db-dup-sort")]
fn del(
&mut self,
db: &Self::Database,
key: &[u8],
value: Option<&[u8]>,
) -> Result<(), Self::Error>;
fn clear_db(&mut self, db: &Self::Database) -> Result<(), Self::Error>;
fn commit(self) -> Result<(), Self::Error>;
fn abort(self);
}
pub trait BackendRoCursorTransaction<'t>: BackendRoTransaction {
type RoCursor: BackendRoCursor<'t>;
fn open_ro_cursor(&'t self, db: &Self::Database) -> Result<Self::RoCursor, Self::Error>;
}
pub trait BackendRwCursorTransaction<'t>: BackendRwTransaction {
type RoCursor: BackendRoCursor<'t>;
fn open_ro_cursor(&'t self, db: &Self::Database) -> Result<Self::RoCursor, Self::Error>;
}
pub trait BackendRoCursor<'c>: Debug {
type Iter: BackendIter<'c>;
fn into_iter(self) -> Self::Iter;
fn into_iter_from<K>(self, key: K) -> Self::Iter
where
K: AsRef<[u8]> + 'c;
fn into_iter_dup_of<K>(self, key: K) -> Self::Iter
where
K: AsRef<[u8]> + 'c;
}
pub trait BackendIter<'i> {
type Error: BackendError;
#[allow(clippy::type_complexity)]
fn next(&mut self) -> Option<Result<(&'i [u8], &'i [u8]), Self::Error>>;
}