swift-nio-extras/Sources/NIOExtras/PCAPRingBuffer.swift
Rick Newton-Rogers 3f776e9aaf
Migrate CI to use GitHub Actions. (#234)
### Motivation:

To migrate to GitHub actions and centralised infrastructure.

### Modifications:

Changes of note:
* Adopt swift-format using rules from SwiftNIO
* Remove scripts and docker files which are no longer needed

### Result:

Feature parity with old CI.
2024-10-28 14:00:57 +00:00

103 lines
4.1 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2020-2021 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 NIOCore
// MARK: NIOPCAPRingBuffer
/// Storage for the most recent set of packets captured subject to constraints.
/// Use ``addFragment(_:)`` as the sink to a ``NIOWritePCAPHandler`` and call ``emitPCAP()``
/// when you wish to get the recorded data.
/// - Warning: This class is not thread safe so should only be called from one thread.
public class NIOPCAPRingBuffer {
private var pcapFragments: CircularBuffer<ByteBuffer>
private var pcapCurrentBytes: Int
private let maximumFragments: Int
private let maximumBytes: Int
/// Initialise the buffer, setting constraints.
/// - Parameters:
/// - maximumFragments: The maximum number of pcap fragments to store.
/// - maximumBytes: The maximum number of bytes to store - note, data written may exceed this by the header size.
public init(maximumFragments: Int, maximumBytes: Int) {
precondition(maximumFragments > 0)
precondition(maximumBytes > 0)
self.maximumFragments = maximumFragments
self.maximumBytes = maximumBytes
self.pcapCurrentBytes = 0
// Don't default to `maximumFragments` as it will be `.max` on some paths.
self.pcapFragments = CircularBuffer()
}
/// Initialise the buffer, setting constraints
/// - Parameter maximumBytes: The maximum number of bytes to store - note, data written may exceed this by the header size.
public convenience init(maximumBytes: Int) {
self.init(maximumFragments: .max, maximumBytes: maximumBytes)
}
/// Initialise the buffer, setting constraints
/// - Parameter maximumFragments: The maximum number of pcap fragments to store.
public convenience init(maximumFragments: Int) {
self.init(maximumFragments: maximumFragments, maximumBytes: .max)
}
@discardableResult
private func popFirst() -> ByteBuffer? {
let popped = self.pcapFragments.popFirst()
if let popped = popped {
self.pcapCurrentBytes -= popped.readableBytes
}
return popped
}
private func append(_ buffer: ByteBuffer) {
self.pcapFragments.append(buffer)
self.pcapCurrentBytes += buffer.readableBytes
assert(self.pcapFragments.count <= self.maximumFragments)
// It's expected that the caller will have made room if required
// for the fragment but we may well go over on bytes - they're
// expected to fix that afterwards.
}
/// Record a fragment into the buffer, making space if required.
/// - Parameter buffer: ByteBuffer containing a pcap fragment to store
public func addFragment(_ buffer: ByteBuffer) {
// Make sure we don't go over on the number of fragments.
if self.pcapFragments.count >= self.maximumFragments {
self.popFirst()
}
precondition(self.pcapFragments.count < self.maximumFragments)
// Add the new fragment
self.append(buffer)
// Trim if we've exceeded byte limit - this could remove multiple, and indeed all fragments.
while self.pcapCurrentBytes > self.maximumBytes {
self.popFirst()
}
precondition(self.pcapCurrentBytes <= self.maximumBytes)
}
/// Emit the captured data to a consuming function; then clear the captured data.
/// - Returns: A circular buffer of captured fragments.
public func emitPCAP() -> CircularBuffer<ByteBuffer> {
let toReturn = self.pcapFragments // Copy before clearing.
self.pcapFragments.removeAll(keepingCapacity: true)
self.pcapCurrentBytes = 0
return toReturn
}
}
@available(*, unavailable)
extension NIOPCAPRingBuffer: Sendable {}