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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::{
fs,
path::{Path, PathBuf},
};
use lmdb::Error as LmdbError;
use super::{
DatabaseFlagsImpl, DatabaseImpl, EnvironmentFlagsImpl, ErrorImpl, InfoImpl, RoTransactionImpl,
RwTransactionImpl, StatImpl,
};
use crate::backend::common::RecoveryStrategy;
use crate::backend::traits::{
BackendEnvironment, BackendEnvironmentBuilder, BackendInfo, BackendIter, BackendRoCursor,
BackendRoCursorTransaction, BackendStat,
};
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub struct EnvironmentBuilderImpl {
builder: lmdb::EnvironmentBuilder,
env_path_type: EnvironmentPathType,
env_lock_type: EnvironmentLockType,
env_db_type: EnvironmentDefaultDbType,
make_dir_if_needed: bool,
}
impl<'b> BackendEnvironmentBuilder<'b> for EnvironmentBuilderImpl {
type Environment = EnvironmentImpl;
type Error = ErrorImpl;
type Flags = EnvironmentFlagsImpl;
fn new() -> EnvironmentBuilderImpl {
EnvironmentBuilderImpl {
builder: lmdb::Environment::new(),
env_path_type: EnvironmentPathType::SubDir,
env_lock_type: EnvironmentLockType::Lockfile,
env_db_type: EnvironmentDefaultDbType::SingleDatabase,
make_dir_if_needed: false,
}
}
fn set_flags<T>(&mut self, flags: T) -> &mut Self
where
T: Into<Self::Flags>,
{
let flags = flags.into();
if flags.0 == lmdb::EnvironmentFlags::NO_SUB_DIR {
self.env_path_type = EnvironmentPathType::NoSubDir;
}
if flags.0 == lmdb::EnvironmentFlags::NO_LOCK {
self.env_lock_type = EnvironmentLockType::NoLockfile;
}
self.builder.set_flags(flags.0);
self
}
fn set_max_readers(&mut self, max_readers: u32) -> &mut Self {
self.builder.set_max_readers(max_readers);
self
}
fn set_max_dbs(&mut self, max_dbs: u32) -> &mut Self {
if max_dbs > 0 {
self.env_db_type = EnvironmentDefaultDbType::MultipleNamedDatabases
}
self.builder.set_max_dbs(max_dbs);
self
}
fn set_map_size(&mut self, size: usize) -> &mut Self {
self.builder.set_map_size(size);
self
}
fn set_make_dir_if_needed(&mut self, make_dir_if_needed: bool) -> &mut Self {
self.make_dir_if_needed = make_dir_if_needed;
self
}
/// **UNIMPLEMENTED.** Will panic at runtime.
fn set_corruption_recovery_strategy(&mut self, _strategy: RecoveryStrategy) -> &mut Self {
// Unfortunately, when opening a database, LMDB doesn't handle all the ways it could have
// been corrupted. Prefer using the `SafeMode` backend if this is important.
unimplemented!();
}
fn open(&self, path: &Path) -> Result<Self::Environment, Self::Error> {
match self.env_path_type {
EnvironmentPathType::NoSubDir => {
if !path.is_file() {
return Err(ErrorImpl::UnsuitableEnvironmentPath(path.into()));
}
}
EnvironmentPathType::SubDir => {
if !path.is_dir() {
if !self.make_dir_if_needed {
return Err(ErrorImpl::UnsuitableEnvironmentPath(path.into()));
}
fs::create_dir_all(path)?;
}
}
}
self.builder
.open(path)
.map_err(ErrorImpl::LmdbError)
.and_then(|lmdbenv| {
EnvironmentImpl::new(
path,
self.env_path_type,
self.env_lock_type,
self.env_db_type,
lmdbenv,
)
})
}
}
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum EnvironmentPathType {
SubDir,
NoSubDir,
}
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum EnvironmentLockType {
Lockfile,
NoLockfile,
}
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum EnvironmentDefaultDbType {
SingleDatabase,
MultipleNamedDatabases,
}
#[derive(Debug)]
pub struct EnvironmentImpl {
path: PathBuf,
env_path_type: EnvironmentPathType,
env_lock_type: EnvironmentLockType,
env_db_type: EnvironmentDefaultDbType,
lmdbenv: lmdb::Environment,
}
impl EnvironmentImpl {
pub(crate) fn new(
path: &Path,
env_path_type: EnvironmentPathType,
env_lock_type: EnvironmentLockType,
env_db_type: EnvironmentDefaultDbType,
lmdbenv: lmdb::Environment,
) -> Result<EnvironmentImpl, ErrorImpl> {
Ok(EnvironmentImpl {
path: path.to_path_buf(),
env_path_type,
env_lock_type,
env_db_type,
lmdbenv,
})
}
}
impl<'e> BackendEnvironment<'e> for EnvironmentImpl {
type Database = DatabaseImpl;
type Error = ErrorImpl;
type Flags = DatabaseFlagsImpl;
type Info = InfoImpl;
type RoTransaction = RoTransactionImpl<'e>;
type RwTransaction = RwTransactionImpl<'e>;
type Stat = StatImpl;
fn get_dbs(&self) -> Result<Vec<Option<String>>, Self::Error> {
if self.env_db_type == EnvironmentDefaultDbType::SingleDatabase {
return Ok(vec![None]);
}
let db = self
.lmdbenv
.open_db(None)
.map(DatabaseImpl)
.map_err(ErrorImpl::LmdbError)?;
let reader = self.begin_ro_txn()?;
let cursor = reader.open_ro_cursor(&db)?;
let mut iter = cursor.into_iter();
let mut store = vec![];
while let Some(result) = iter.next() {
let (key, _) = result?;
let name = String::from_utf8(key.to_owned())
.map_err(|_| ErrorImpl::LmdbError(lmdb::Error::Corrupted))?;
store.push(Some(name));
}
Ok(store)
}
fn open_db(&self, name: Option<&str>) -> Result<Self::Database, Self::Error> {
self.lmdbenv
.open_db(name)
.map(DatabaseImpl)
.map_err(ErrorImpl::LmdbError)
}
fn create_db(
&self,
name: Option<&str>,
flags: Self::Flags,
) -> Result<Self::Database, Self::Error> {
self.lmdbenv
.create_db(name, flags.0)
.map(DatabaseImpl)
.map_err(ErrorImpl::LmdbError)
}
fn begin_ro_txn(&'e self) -> Result<Self::RoTransaction, Self::Error> {
self.lmdbenv
.begin_ro_txn()
.map(RoTransactionImpl)
.map_err(ErrorImpl::LmdbError)
}
fn begin_rw_txn(&'e self) -> Result<Self::RwTransaction, Self::Error> {
self.lmdbenv
.begin_rw_txn()
.map(RwTransactionImpl)
.map_err(ErrorImpl::LmdbError)
}
fn sync(&self, force: bool) -> Result<(), Self::Error> {
self.lmdbenv.sync(force).map_err(ErrorImpl::LmdbError)
}
fn stat(&self) -> Result<Self::Stat, Self::Error> {
self.lmdbenv
.stat()
.map(StatImpl)
.map_err(ErrorImpl::LmdbError)
}
fn info(&self) -> Result<Self::Info, Self::Error> {
self.lmdbenv
.info()
.map(InfoImpl)
.map_err(ErrorImpl::LmdbError)
}
fn freelist(&self) -> Result<usize, Self::Error> {
self.lmdbenv.freelist().map_err(ErrorImpl::LmdbError)
}
fn load_ratio(&self) -> Result<Option<f32>, Self::Error> {
let stat = self.stat()?;
let info = self.info()?;
let freelist = self.freelist()?;
let last_pgno = info.last_pgno() + 1; // pgno is 0 based.
let total_pgs = info.map_size() / stat.page_size();
if freelist > last_pgno {
return Err(ErrorImpl::LmdbError(LmdbError::Corrupted));
}
let used_pgs = last_pgno - freelist;
Ok(Some(used_pgs as f32 / total_pgs as f32))
}
fn set_map_size(&self, size: usize) -> Result<(), Self::Error> {
self.lmdbenv
.set_map_size(size)
.map_err(ErrorImpl::LmdbError)
}
fn get_files_on_disk(&self) -> Vec<PathBuf> {
let mut store = vec![];
if self.env_path_type == EnvironmentPathType::NoSubDir {
// The option NO_SUB_DIR could change the default directory layout; therefore this should
// probably return the path used to create environment, along with the custom lockfile
// when available.
unimplemented!();
}
let mut db_filename = self.path.clone();
db_filename.push("data.mdb");
store.push(db_filename);
if self.env_lock_type == EnvironmentLockType::Lockfile {
let mut lock_filename = self.path.clone();
lock_filename.push("lock.mdb");
store.push(lock_filename);
}
store
}
}