odbus: import dbus-1 OO wrapper library

From a7cef404c1

To be used by upcoming code.

src/lib/dbus/Watch.cxx

@@ -0,0 +1,135 @@
+/*
+ * Copyright 2007-2018 Content Management AG
+ * All rights reserved.
+ *
+ * author: Max Kellermann <mk@cm4all.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "Watch.hxx"
+
+namespace ODBus {
+
+WatchManager::Watch::Watch(EventLoop &event_loop,
+			   WatchManager &_parent, DBusWatch &_watch) noexcept
+	:SocketMonitor(event_loop),
+	 parent(_parent), watch(_watch)
+{
+	Toggled();
+}
+
+static constexpr unsigned
+DbusToLibevent(unsigned flags) noexcept
+{
+	return ((flags & DBUS_WATCH_READABLE) != 0) * SocketMonitor::READ |
+		((flags & DBUS_WATCH_WRITABLE) != 0) * SocketMonitor::WRITE;
+}
+
+void
+WatchManager::Watch::Toggled() noexcept
+{
+	if (SocketMonitor::IsDefined())
+		SocketMonitor::Cancel();
+
+	if (dbus_watch_get_enabled(&watch)) {
+		SocketMonitor::Open(SocketDescriptor(dbus_watch_get_unix_fd(&watch)));
+		SocketMonitor::Schedule(DbusToLibevent(dbus_watch_get_flags(&watch)));
+	}
+}
+
+static constexpr unsigned
+LibeventToDbus(unsigned flags) noexcept
+{
+	return ((flags & SocketMonitor::READ) != 0) * DBUS_WATCH_READABLE |
+		((flags & SocketMonitor::WRITE) != 0) * DBUS_WATCH_WRITABLE;
+}
+
+bool
+WatchManager::Watch::OnSocketReady(unsigned events) noexcept
+{
+	/* copy the "parent" reference to the stack, because the
+	   dbus_watch_handle() may invoke WatchManager::Remove() which
+	   may destroy this object */
+	auto &_parent = parent;
+
+	dbus_watch_handle(&watch, LibeventToDbus(events));
+
+	_parent.ScheduleDispatch();
+	return true;
+}
+
+void
+WatchManager::Shutdown() noexcept
+{
+	if (!connection)
+		return;
+
+	dbus_connection_set_watch_functions(connection,
+					    nullptr, nullptr,
+					    nullptr, nullptr,
+					    nullptr);
+	watches.clear();
+	defer_dispatch.Cancel();
+}
+
+void
+WatchManager::Dispatch() noexcept
+{
+	while (dbus_connection_dispatch(connection) == DBUS_DISPATCH_DATA_REMAINS) {}
+
+	if (!dbus_connection_get_is_connected(connection)) {
+		Shutdown();
+		observer.OnDBusClosed();
+	}
+}
+
+bool
+WatchManager::Add(DBusWatch *watch) noexcept
+{
+	watches.emplace(std::piecewise_construct,
+			std::forward_as_tuple(watch),
+			std::forward_as_tuple(GetEventLoop(), *this, *watch));
+	return true;
+}
+
+void
+WatchManager::Remove(DBusWatch *watch) noexcept
+{
+	watches.erase(watch);
+}
+
+void
+WatchManager::Toggled(DBusWatch *watch) noexcept
+{
+	auto i = watches.find(watch);
+	assert(i != watches.end());
+
+	i->second.Toggled();
+}
+
+} /* namespace ODBus */