Add methods to tell if a socket is accepting/reading.

Summary: It's desirable to know if a given server socket is accepting or if a regular UDP socket is reading.

Reviewed By: dddmello

Differential Revision: D16529348

fbshipit-source-id: 2e9a2e505f97344d21449aed7c9effc298877e41

folly/io/async/AsyncUDPServerSocket.h

@@ -158,6 +158,13 @@ class AsyncUDPServerSocket : private AsyncUDPSocket::ReadCallback,
     return evb_;
   }
 
+  /**
+   * Indicates if the current socket is accepting.
+   */
+  bool isAccepting() const {
+    return socket_->isReading();
+  }
+
   /**
    * Pauses accepting datagrams on the underlying socket.
    */

folly/io/async/AsyncUDPSocket.h

@@ -281,6 +281,10 @@ class AsyncUDPSocket : public EventHandler {
     return fd_ != NetworkSocket();
   }
 
+  virtual bool isReading() const {
+    return readCallback_ != nullptr;
+  }
+
   virtual void detachEventBase();
 
   virtual void attachEventBase(folly::EventBase* evb);

folly/io/async/test/AsyncUDPSocketTest.cpp

@@ -150,6 +150,10 @@ class UDPServer {
     socket_->resumeAccepting();
   }
 
+  bool isAccepting() {
+    return socket_->isAccepting();
+  }
+
   // Whether writes from the UDP server should change the port for each message.
   void setChangePortForWrites(bool changePortForWrites) {
     changePortForWrites_ = changePortForWrites;
@@ -406,11 +410,13 @@ TEST_F(AsyncSocketIntegrationTest, PingPongPauseResumeListening) {
 
   // Exchange should not happen when paused.
   server->pauseAccepting();
+  EXPECT_FALSE(server->isAccepting());
   auto pausedClient = performPingPongTest(server->address(), folly::none);
   ASSERT_EQ(pausedClient->pongRecvd(), 0);
 
   // Exchange does occur after resuming.
   server->resumeAccepting();
+  EXPECT_TRUE(server->isAccepting());
   auto pingClient = performPingPongTest(server->address(), folly::none);
   ASSERT_GT(pingClient->pongRecvd(), 0);
 }