event/SocketMonitor: refactor to SocketEvent

Similar to commits 1686f4e857 and 30a5dd267b
2020-10-14 14:24:16 +02:00
parent 4d68a12f03
commit 5a4055fb08
26 changed files with 282 additions and 261 deletions
@@ -0,0 +1,107 @@
+/*
+ * Copyright 2003-2020 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "SocketEvent.hxx"
+#include "Loop.hxx"
+#include "event/Features.h"
+
+#include <cassert>
+#include <utility>
+
+#ifdef USE_EPOLL
+#include <cerrno>
+#endif
+
+void
+SocketEvent::Dispatch() noexcept
+{
+	const unsigned flags = std::exchange(ready_flags, 0) &
+		(GetScheduledFlags() | IMPLICIT_FLAGS);
+
+	if (flags != 0)
+		callback(flags);
+}
+
+SocketEvent::~SocketEvent() noexcept
+{
+	if (IsDefined())
+		Cancel();
+}
+
+void
+SocketEvent::Open(SocketDescriptor _fd) noexcept
+{
+	assert(!fd.IsDefined());
+	assert(_fd.IsDefined());
+
+	fd = _fd;
+}
+
+SocketDescriptor
+SocketEvent::Steal() noexcept
+{
+	assert(IsDefined());
+
+	Cancel();
+
+	return std::exchange(fd, SocketDescriptor::Undefined());
+}
+
+void
+SocketEvent::Close() noexcept
+{
+	Steal().Close();
+}
+
+bool
+SocketEvent::Schedule(unsigned flags) noexcept
+{
+	assert(IsDefined());
+
+	if (flags == GetScheduledFlags())
+		return true;
+
+	bool success;
+	if (scheduled_flags == 0)
+		success = loop.AddFD(fd.Get(), flags, *this);
+	else if (flags == 0)
+		success = loop.RemoveFD(fd.Get());
+	else
+		success = loop.ModifyFD(fd.Get(), flags, *this);
+
+	if (success)
+		scheduled_flags = flags;
+#ifdef USE_EPOLL
+	else if (errno == EBADF || errno == ENOENT)
+		/* the socket was probably closed by somebody else
+		   (EBADF) or a new file descriptor with the same
+		   number was created but not registered already
+		   (ENOENT) - we can assume that there are no
+		   scheduled events */
+		/* note that when this happens, we're actually lucky
+		   that it has failed - imagine another thread may
+		   meanwhile have created something on the same file
+		   descriptor number, and has registered it; the
+		   epoll_ctl() call above would then have succeeded,
+		   but broke the other thread's epoll registration */
+		scheduled_flags = 0;
+#endif
+
+	return success;
+}