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/*
This source file is part of the Swift.org open source project
Copyright (c) 2021 Apple Inc. and the Swift project authors
Licensed under Apache License v2.0 with Runtime Library Exception
See https://swift.org/LICENSE.txt for license information
See https://swift.org/CONTRIBUTORS.txt for Swift project authors
*/
import Foundation
import CLMDB
/**
A general utility class for LMDB.
- Note: LMDB wrapper doesn't use any writing queue to serialize writes, but it relies on LMDB's low level solution.
Reads are never blocked, but writes are serialized using a mutually exclusive lock at the database level.
*/
final class LMDB {
#if os(Windows)
public typealias ModeType = CInt
#else
public typealias ModeType = mode_t
#endif
/// Default instance.
public static var `default` = LMDB()
/// Returns the library version.
public var version: Version {
return [Int(MDB_VERSION_MAJOR), Int(MDB_VERSION_MINOR), Int(MDB_VERSION_PATCH)]
}
/// The default number of databases to open which is `0`. The `0` value means no named databases can be opened.
public static let defaultMaxDBs: UInt32 = 0
/// The default number of readers to open which is `126`.
public static let defaultMaxReaders: UInt32 = 126
/// The default number of map size which is `10485760`.
public static let defaultMapSize: size_t = 10485760
/// The default file mode for opening an environment which is `744`.
#if os(Windows)
public static let defaultFileMode: ModeType = _S_IREAD | _S_IWRITE
#else
public static let defaultFileMode: ModeType = S_IRWXU | S_IRGRP | S_IROTH
#endif
}
/**
A type with a customized data representation suited for storage inside an LMDB database.
Types that conform to the `LMDBData` protocol can provide their own representation to be used when converting
an instance to a valid data representation ready for LMDB storage.
> Note: Default implementations for some common Swift types are included. Custom types require an appropriate
implementation of the conversion.
*/
public protocol LMDBData {
init?(data: UnsafeRawBufferPointer)
func read<ResultType>(_ body: (UnsafeRawBufferPointer) throws -> ResultType) rethrows -> ResultType
}
public extension LMDBData {
init?(data: UnsafeRawBufferPointer) {
guard data.count == MemoryLayout<Self>.stride else { return nil }
self = data.baseAddress!.assumingMemoryBound(to: Self.self).pointee
}
func read<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R {
var val = self
return try withUnsafeBytes(of: &val, body)
}
}
extension Data: LMDBData {
public init?(data: UnsafeRawBufferPointer) {
self = Data.init(bytes: data.baseAddress!, count: data.count)
}
public func read<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R{
return try self.withUnsafeBytes({ (ptr) -> R in
return try body(ptr)
})
}
}
extension String: LMDBData {
public init?(data: UnsafeRawBufferPointer) {
self.init(bytes: data, encoding: .utf8)
}
public func read<ResultType>(_ body: (UnsafeRawBufferPointer) throws -> ResultType) rethrows -> ResultType {
return try self.data(using: .utf8)!.read(body)
}
}
// This is required for macOS, for Linux the default implementation works as expected.
extension Array: LMDBData where Element: FixedWidthInteger {
#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
public init?(data: UnsafeRawBufferPointer) {
var array = [Element](repeating: 0, count: data.count / MemoryLayout<Element>.stride)
_ = array.withUnsafeMutableBytes { data.copyBytes(to: $0) }
self = array
}
public func read<R>(_ body: (UnsafeRawBufferPointer) throws -> R) rethrows -> R {
let data = self.withUnsafeBufferPointer { Data(buffer: $0) }
return try data.read(body)
}
#endif
}
extension Bool: LMDBData {}
extension Int: LMDBData {}
extension Int8: LMDBData {}
extension Int16: LMDBData {}
extension Int32: LMDBData {}
extension Int64: LMDBData {}
extension UInt: LMDBData {}
extension UInt8: LMDBData {}
extension UInt16: LMDBData {}
extension UInt32: LMDBData {}
extension UInt64: LMDBData {}
extension Float: LMDBData {}
extension Double: LMDBData {}
extension Date: LMDBData {}
extension URL: LMDBData {}
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