Strict concurrency for the chat examples (apple#3104)

Motivation:

Our next suite of examples for strict concurrency are the chat ones.
These are very similar to the rest: either no violation at all, or just
a need to use the sync operations on pipeline setup.

Modifications:

- Use sync operations
- Lock in strict concurrency checking

Result:

We continue our march.

Co-authored-by: Rick Newton-Rogers <rnro@apple.com>

Author: Lukasa

Package.swift

@@ -334,7 +334,8 @@ let package = Package(
                 "NIOCore",
                 "NIOConcurrencyHelpers",
             ],
-            exclude: ["README.md"]
+            exclude: ["README.md"],
+            swiftSettings: strictConcurrencySettings
         ),
         .executableTarget(
             name: "NIOChatClient",
@@ -343,7 +344,8 @@ let package = Package(
                 "NIOCore",
                 "NIOConcurrencyHelpers",
             ],
-            exclude: ["README.md"]
+            exclude: ["README.md"],
+            swiftSettings: strictConcurrencySettings
         ),
         .executableTarget(
             name: "NIOWebSocketServer",
@@ -370,7 +372,8 @@ let package = Package(
             dependencies: [
                 "NIOPosix",
                 "NIOCore",
-            ]
+            ],
+            swiftSettings: strictConcurrencySettings
         ),
         .executableTarget(
             name: "NIOUDPEchoServer",

Sources/NIOChatClient/main.swift

@@ -18,19 +18,9 @@ private final class ChatHandler: ChannelInboundHandler {
     public typealias InboundIn = ByteBuffer
     public typealias OutboundOut = ByteBuffer
 
-    private func printByte(_ byte: UInt8) {
-        #if os(Android)
-        print(Character(UnicodeScalar(byte)), terminator: "")
-        #else
-        fputc(Int32(byte), stdout)
-        #endif
-    }
-
     public func channelRead(context: ChannelHandlerContext, data: NIOAny) {
-        var buffer = Self.unwrapInboundIn(data)
-        while let byte: UInt8 = buffer.readInteger() {
-            printByte(byte)
-        }
+        let buffer = Self.unwrapInboundIn(data)
+        print(String(buffer: buffer))
     }
 
     public func errorCaught(context: ChannelHandlerContext, error: Error) {
@@ -47,7 +37,9 @@ let bootstrap = ClientBootstrap(group: group)
     // Enable SO_REUSEADDR.
     .channelOption(.socketOption(.so_reuseaddr), value: 1)
     .channelInitializer { channel in
-        channel.pipeline.addHandler(ChatHandler())
+        channel.eventLoop.makeCompletedFuture {
+            try channel.pipeline.syncOperations.addHandler(ChatHandler())
+        }
     }
 defer {
     try! group.syncShutdownGracefully()

Sources/NIOMulticastChat/main.swift

@@ -72,8 +72,8 @@ let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
 var datagramBootstrap = DatagramBootstrap(group: group)
     .channelOption(.socketOption(.so_reuseaddr), value: 1)
     .channelInitializer { channel in
-        channel.pipeline.addHandler(ChatMessageEncoder()).flatMap {
-            channel.pipeline.addHandler(ChatMessageDecoder())
+        channel.eventLoop.makeCompletedFuture {
+            try channel.pipeline.syncOperations.addHandlers(ChatMessageEncoder(), ChatMessageDecoder())
         }
     }