Merge pull request #60 from envoy/fang/bugfixes/59/selector-event-loo…

…p-reference-cycle-bug

Fix event loop reference cycle bug

Sources/SelectorEventLoop.swift

@@ -48,14 +48,18 @@ public final class SelectorEventLoop: EventLoop {
         IOUtils.setBlocking(fileDescriptor: pipeReceiver, blocking: false)
         // subscribe to pipe receiver read-ready event, do nothing, just allow selector
         // to be interrupted
+
+        // Notice: we use a local copy of pipeReceiver to avoid referencing self
+        // here, thus we won't have reference cycle problem
+        let localPipeReceiver = pipeReceiver
         setReader(pipeReceiver) {
             // consume the pipe receiver, so that it won't keep triggering read event
             let size = PIPE_BUF
             var bytes = Data(count: Int(size))
             var readSize = 1
             while readSize > 0 {
                 readSize = bytes.withUnsafeMutableBytes { pointer in
-                    return SystemLibrary.read(self.pipeReceiver, pointer, Int(size))
+                    return SystemLibrary.read(localPipeReceiver, pointer, Int(size))
                 }
             }
         }

Tests/EmbassyTests/SelectorEventLoopTests.swift

@@ -218,4 +218,12 @@ class SelectorEventLoopTests: XCTestCase {
         }
         XCTAssertEqual(readData, ["hello", "baby"])
     }
+
+    func testEventLoopReferenceCycle() {
+        // Notice: we had a reference cycle from the setReader callback to the
+        // selector loop object before, we ensure that when loop is not hold
+        // by anybody, it should be released here
+        weak var loop = try! SelectorEventLoop(selector: try! TestingSelector())
+        XCTAssertNil(loop)
+    }
 }