event/EpollEvents: add ANY_HANGUP

Portable abstraction that allows matching both EPOLLHUP and the
Linux-specific EPOLLRDHUP.

Author: MaxKellermann

src/event/EpollEvents.hxx

@@ -12,10 +12,16 @@ struct EpollEvents {
 	static constexpr unsigned HANGUP = EPOLLHUP;
 	static constexpr unsigned READ_HANGUP = EPOLLRDHUP;
 
+	/**
+	 * Any kind of hangup, i.e. the normal EPOLLHUP plus the
+	 * Linux-specific EPOLLRDHUP.
+	 */
+	static constexpr unsigned ANY_HANGUP = HANGUP|READ_HANGUP;
+
 	/**
 	 * A mask containing all events which indicate a dead socket
 	 * connection (i.e. error or hangup).  It may still be
 	 * possible to receive pending data from the socket buffer.
 	 */
-	static constexpr unsigned DEAD_MASK = ERROR|HANGUP|READ_HANGUP;
+	static constexpr unsigned DEAD_MASK = ERROR|ANY_HANGUP;
 };

src/event/PollEvents.hxx

@@ -10,10 +10,16 @@ struct PollEvents {
 	static constexpr unsigned ERROR = POLLERR;
 	static constexpr unsigned HANGUP = POLLHUP;
 
+	/**
+	 * Any kind of hangup, i.e. the normal EPOLLHUP plus the
+	 * Linux-specific EPOLLRDHUP.
+	 */
+	static constexpr unsigned ANY_HANGUP = HANGUP;
+
 	/**
 	 * A mask containing all events which indicate a dead socket
 	 * connection (i.e. error or hangup).  It may still be
 	 * possible to receive pending data from the socket buffer.
 	 */
-	static constexpr unsigned DEAD_MASK = ERROR|HANGUP;
+	static constexpr unsigned DEAD_MASK = ERROR|ANY_HANGUP;
 };

src/event/WinSelectEvents.hxx

@@ -16,10 +16,16 @@ struct WinSelectEvents {
 	static constexpr unsigned ERROR = 0;
 	static constexpr unsigned HANGUP = 0;
 
+	/**
+	 * Any kind of hangup, i.e. the normal EPOLLHUP plus the
+	 * Linux-specific EPOLLRDHUP.
+	 */
+	static constexpr unsigned ANY_HANGUP = HANGUP;
+
 	/**
 	 * A mask containing all events which indicate a dead socket
 	 * connection (i.e. error or hangup).  It may still be
 	 * possible to receive pending data from the socket buffer.
 	 */
-	static constexpr unsigned DEAD_MASK = ERROR|HANGUP;
+	static constexpr unsigned DEAD_MASK = ERROR|ANY_HANGUP;
 };