mirror of
https://github.com/apple/swift-nio-extras.git
synced 2025-05-16 01:42:29 +08:00
10e173cbed
Provide a decoder for frames with a fixed length. Motivation: This was motivated by the issue https://github.com/apple/swift-nio/issues/474 as a good first issue. Modifications: Implemented a FixedLengthFrameDecoder as well as tests. Result: Users can decode fixed length frames.
62 lines
1.9 KiB
Swift
62 lines
1.9 KiB
Swift
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This source file is part of the SwiftNIO open source project
|
|
//
|
|
// Copyright (c) 2017-2018 Apple Inc. and the SwiftNIO project authors
|
|
// Licensed under Apache License v2.0
|
|
//
|
|
// See LICENSE.txt for license information
|
|
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
|
|
//
|
|
// SPDX-License-Identifier: Apache-2.0
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
import NIO
|
|
///
|
|
/// A decoder that splits the received `ByteBuffer` by a fixed number
|
|
/// of bytes. For example, if you received the following four fragmented packets:
|
|
///
|
|
/// +---+----+------+----+
|
|
/// | A | BC | DEFG | HI |
|
|
/// +---+----+------+----+
|
|
///
|
|
/// A `FixedLengthFrameDecoder` will decode them into the
|
|
/// following three packets with the fixed length:
|
|
///
|
|
/// +-----+-----+-----+
|
|
/// | ABC | DEF | GHI |
|
|
/// +-----+-----+-----+
|
|
///
|
|
public final class FixedLengthFrameDecoder: ByteToMessageDecoder {
|
|
public typealias InboundIn = ByteBuffer
|
|
public typealias InboundOut = ByteBuffer
|
|
|
|
public var cumulationBuffer: ByteBuffer?
|
|
|
|
private let frameLength: Int
|
|
|
|
/// Create `FixedLengthFrameDecoder` with a given frame length.
|
|
///
|
|
/// - parameters:
|
|
/// - frameLength: The length of a frame.
|
|
public init(frameLength: Int) {
|
|
self.frameLength = frameLength
|
|
}
|
|
|
|
public func decode(ctx: ChannelHandlerContext, buffer: inout ByteBuffer) throws -> DecodingState {
|
|
guard let slice = buffer.readSlice(length: frameLength) else {
|
|
return .needMoreData
|
|
}
|
|
|
|
ctx.fireChannelRead(self.wrapInboundOut(slice))
|
|
return .continue
|
|
}
|
|
|
|
public func handlerRemoved(ctx: ChannelHandlerContext) {
|
|
if let buffer = cumulationBuffer, buffer.readableBytes > 0 {
|
|
ctx.fireErrorCaught(NIOExtrasErrors.LeftOverBytesError(leftOverBytes: buffer))
|
|
}
|
|
}
|
|
}
|