Embedded: getOption(.allowRemoteHalfClosure) -> OK

Motivation:

In `swift-nio-ssl`, I am currently working on allowing half-closures
which relies on querying the underlying channel if
`ChannelOptions.Types.AllowRemoteHalfClosureOption` is enabled. As a lot of
`swift-nio-ssl`'s tests rely on `EmbeddedChannel` and it did not support
this option, a lot of the tests failed.

Modifications:

* add a `public var allowRemoteHalfClosure` to `EmbeddedChannel`
* enable setting/getting
  `ChannelOptions.Types.AllowRemoteHalfClosureOption` in
`EmbeddedChannel` (only modifies the `allowRemoteHalfClosure` variable
* add test for new behaviour

Sources/NIOEmbedded/Embedded.swift

@@ -281,7 +281,7 @@ class EmbeddedChannelCore: ChannelCore {
     /// Contains the flushed items that went into the `Channel` (and on a regular channel would have hit the network).
     @usableFromInline
     var outboundBuffer: CircularBuffer<NIOAny> = CircularBuffer()
-    
+
     /// Contains observers that want to consume the first element that would be appended to the `outboundBuffer`
     @usableFromInline
     var outboundBufferConsumer: Deque<(NIOAny) -> Void> = []
@@ -294,7 +294,7 @@ class EmbeddedChannelCore: ChannelCore {
     /// regular `Channel` these items would be lost.
     @usableFromInline
     var inboundBuffer: CircularBuffer<NIOAny> = CircularBuffer()
-    
+
     /// Contains observers that want to consume the first element that would be appended to the `inboundBuffer`
     @usableFromInline
     var inboundBufferConsumer: Deque<(NIOAny) -> Void> = []
@@ -551,6 +551,9 @@ public final class EmbeddedChannel: Channel {
     /// - note: An `EmbeddedChannel` starts _inactive_ and can be activated, for example by calling `connect`.
     public var isActive: Bool { return channelcore.isActive }
 
+    /// - see: `ChannelOptions.Types.AllowRemoteHalfClosureOption`
+    public var allowRemoteHalfClosure: Bool = false
+
     /// - see: `Channel.closeFuture`
     public var closeFuture: EventLoopFuture<Void> { return channelcore.closePromise.futureResult }
 
@@ -749,7 +752,7 @@ public final class EmbeddedChannel: Channel {
         let handlers = handler.map { [$0] } ?? []
         self.init(handlers: handlers, loop: loop)
     }
-    
+
     /// Create a new instance.
     ///
     /// During creation it will automatically also register itself on the `EmbeddedEventLoop`.
@@ -776,8 +779,12 @@ public final class EmbeddedChannel: Channel {
 
     @inlinable
     internal func setOptionSync<Option: ChannelOption>(_ option: Option, value: Option.Value) {
-        // No options supported
-        fatalError("no options supported")
+        if option is ChannelOptions.Types.AllowRemoteHalfClosureOption {
+            self.allowRemoteHalfClosure = value as! Bool
+            return
+        }
+        // No other options supported
+        fatalError("option not supported")
     }
 
     /// - see: `Channel.getOption`
@@ -791,6 +798,9 @@ public final class EmbeddedChannel: Channel {
         if option is ChannelOptions.Types.AutoReadOption {
             return true as! Option.Value
         }
+        if option is ChannelOptions.Types.AllowRemoteHalfClosureOption {
+            return self.allowRemoteHalfClosure as! Option.Value
+        }
         fatalError("option \(option) not supported")
     }
 

Tests/NIOEmbeddedTests/EmbeddedChannelTest.swift

@@ -69,50 +69,50 @@ class ChannelLifecycleHandler: ChannelInboundHandler {
 }
 
 class EmbeddedChannelTest: XCTestCase {
-    
+
     func testSingleHandlerInit() {
         class Handler: ChannelInboundHandler {
             typealias InboundIn = Never
         }
-        
+
         let channel = EmbeddedChannel(handler: Handler())
         XCTAssertNoThrow(try channel.pipeline.handler(type: Handler.self).wait())
     }
-    
+
     func testSingleHandlerInitNil() {
         class Handler: ChannelInboundHandler {
             typealias InboundIn = Never
         }
-        
+
         let channel = EmbeddedChannel(handler: nil)
         XCTAssertThrowsError(try channel.pipeline.handler(type: Handler.self).wait()) { e in
             XCTAssertEqual(e as? ChannelPipelineError, .notFound)
         }
     }
-    
+
     func testMultipleHandlerInit() {
         class Handler: ChannelInboundHandler, RemovableChannelHandler {
             typealias InboundIn = Never
             let identifier: String
-            
+
             init(identifier: String) {
                 self.identifier = identifier
             }
         }
-        
+
         let channel = EmbeddedChannel(
             handlers: [Handler(identifier: "0"), Handler(identifier: "1"), Handler(identifier: "2")]
         )
         XCTAssertNoThrow(XCTAssertEqual(try channel.pipeline.handler(type: Handler.self).wait().identifier, "0"))
         XCTAssertNoThrow(try channel.pipeline.removeHandler(name: "handler0").wait())
-        
+
         XCTAssertNoThrow(XCTAssertEqual(try channel.pipeline.handler(type: Handler.self).wait().identifier, "1"))
         XCTAssertNoThrow(try channel.pipeline.removeHandler(name: "handler1").wait())
-        
+
         XCTAssertNoThrow(XCTAssertEqual(try channel.pipeline.handler(type: Handler.self).wait().identifier, "2"))
         XCTAssertNoThrow(try channel.pipeline.removeHandler(name: "handler2").wait())
     }
-    
+
     func testWriteOutboundByteBuffer() throws {
         let channel = EmbeddedChannel()
         var buf = channel.allocator.buffer(capacity: 1024)
@@ -481,13 +481,27 @@ class EmbeddedChannelTest: XCTestCase {
         XCTAssertEqual(invocations, 1)
     }
 
-    func testSyncOptionsAreSupported() throws {
+    func testGetChannelOptionAutoReadIsSupported() {
         let channel = EmbeddedChannel()
         let options = channel.syncOptions
         XCTAssertNotNil(options)
         // Unconditionally returns true.
         XCTAssertEqual(try options?.getOption(ChannelOptions.autoRead), true)
-        // (Setting options isn't supported.)
+    }
+
+    func testSetGetChannelOptionAllowRemoteHalfClosueIsSupported() {
+        let channel = EmbeddedChannel()
+        let options = channel.syncOptions
+        XCTAssertNotNil(options)
+
+        // allowRemoteHalfClosure should be false by default
+        XCTAssertEqual(try options?.getOption(ChannelOptions.allowRemoteHalfClosure), false)
+
+        channel.allowRemoteHalfClosure = true
+        XCTAssertEqual(try options?.getOption(ChannelOptions.allowRemoteHalfClosure), true)
+
+        XCTAssertNoThrow(try options?.setOption(ChannelOptions.allowRemoteHalfClosure, value: false))
+        XCTAssertEqual(try options?.getOption(ChannelOptions.allowRemoteHalfClosure), false)
     }
 
     func testLocalAddress0() throws {