event/SocketMonitor: add methods Read(), Write()

src/event/SocketMonitor.hxx

@@ -24,7 +24,10 @@
 
 #include <glib.h>
 
+#include <type_traits>
+
 #include <assert.h>
+#include <stddef.h>
 
 #ifdef WIN32
 /* ERRORis a WIN32 macro that poisons our namespace; this is a
@@ -54,6 +57,8 @@ public:
 	static constexpr unsigned ERROR = G_IO_ERR;
 	static constexpr unsigned HANGUP = G_IO_HUP;
 
+	typedef std::make_signed<size_t>::type ssize_t;
+
 	SocketMonitor(EventLoop &_loop)
 		:fd(-1), loop(_loop), source(nullptr) {}
 
@@ -106,6 +111,9 @@ public:
 		poll.events &= ~WRITE;
 	}
 
+	ssize_t Read(void *data, size_t length);
+	ssize_t Write(const void *data, size_t length);
+
 protected:
 	virtual void OnSocketReady(unsigned flags) = 0;