Replace NEKit dependency with reduced subset

GlassVPN/zhuhaow-NEKit/Socket/SocketProtocol.swift

@@ -0,0 +1,155 @@
+import Foundation
+
+/**
+ The current connection status of the socket.
+
+ - Invalid:       The socket is just created but never connects.
+ - Connecting:    The socket is connecting.
+ - Established:   The connection is established.
+ - Disconnecting: The socket is disconnecting.
+ - Closed:        The socket is closed.
+ */
+public enum SocketStatus {
+    /// The socket is just created but never connects.
+    case invalid,
+
+    /// The socket is connecting.
+    connecting,
+
+    /// The connection is established.
+    established,
+
+    /// The socket is disconnecting.
+    disconnecting,
+
+    /// The socket is closed.
+    closed
+}
+
+/// Protocol for socket with various functions.
+///
+/// Any concrete implementation does not need to be thread-safe.
+public protocol SocketProtocol: class {
+    /// The underlying TCP socket transmitting data.
+    var socket: RawTCPSocketProtocol! { get }
+
+    /// The delegate instance.
+    var delegate: SocketDelegate? { get set }
+
+    /// The current connection status of the socket.
+    var status: SocketStatus { get }
+
+//    /// The description of the currect status.
+//    var statusDescription: String { get }
+
+    /// If the socket is disconnected.
+    var isDisconnected: Bool { get }
+
+    /// The type of the socket.
+    var typeName: String { get }
+
+    var readStatusDescription: String { get }
+
+    var writeStatusDescription: String { get }
+
+    /**
+     Read data from the socket.
+
+     - warning: This should only be called after the last read is finished, i.e., `delegate?.didReadData()` is called.
+     */
+    func readData()
+
+    /**
+     Send data to remote.
+
+     - parameter data: Data to send.
+     - warning: This should only be called after the last write is finished, i.e., `delegate?.didWriteData()` is called.
+     */
+    func write(data: Data)
+
+    /**
+     Disconnect the socket elegantly.
+     */
+    func disconnect(becauseOf error: Error?)
+
+    /**
+     Disconnect the socket immediately.
+     */
+    func forceDisconnect(becauseOf error: Error?)
+}
+
+extension SocketProtocol {
+    /// If the socket is disconnected.
+    public var isDisconnected: Bool {
+        return status == .closed || status == .invalid
+    }
+
+    public var typeName: String {
+        return String(describing: type(of: self))
+    }
+
+    public var readStatusDescription: String {
+        return "\(status)"
+    }
+
+    public var writeStatusDescription: String {
+        return "\(status)"
+    }
+}
+
+/// The delegate protocol to handle the events from a socket.
+public protocol SocketDelegate : class {
+    /**
+     The socket did connect to remote.
+
+     - parameter adapterSocket: The connected socket.
+     */
+    func didConnectWith(adapterSocket: AdapterSocket)
+
+    /**
+     The socket did disconnect.
+
+     This should only be called once in the entire lifetime of a socket. After this is called, the delegate will not receive any other events from that socket and the socket should be released.
+
+     - parameter socket: The socket which did disconnect.
+     */
+    func didDisconnectWith(socket: SocketProtocol)
+
+    /**
+     The socket did read some data.
+
+     - parameter data:    The data read from the socket.
+     - parameter from:    The socket where the data is read from.
+     */
+    func didRead(data: Data, from: SocketProtocol)
+
+    /**
+     The socket did send some data.
+
+     - parameter data:    The data which have been sent to remote (acknowledged). Note this may not be available since the data may be released to save memory.
+     - parameter by:      The socket where the data is sent out.
+     */
+    func didWrite(data: Data?, by: SocketProtocol)
+
+    /**
+     The socket is ready to forward data back and forth.
+
+     - parameter socket: The socket which becomes ready to forward data.
+     */
+    func didBecomeReadyToForwardWith(socket: SocketProtocol)
+
+    /**
+     Did receive a `ConnectSession` from local now it is time to connect to remote.
+
+     - parameter session: The received `ConnectSession`.
+     - parameter from:    The socket where the `ConnectSession` is received.
+     */
+    func didReceive(session: ConnectSession, from: ProxySocket)
+
+    /**
+     The adapter socket decided to replace itself with a new `AdapterSocket` to connect to remote.
+
+     - parameter newAdapter: The new `AdapterSocket` to replace the old one.
+     */
+    func updateAdapterWith(newAdapter: AdapterSocket)
+}