event/{Coarse,Fine,Far}TimerEvent: aliases for TimerEvent

Preparing for a variant of TimerEvent with coarse 1-second
granularity, but cheaper (with a timer wheel).

src/StateFile.hxx

@@ -21,7 +21,7 @@
 #define MPD_STATE_FILE_HXX
 
 #include "StateFileConfig.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/FarTimerEvent.hxx"
 #include "util/Compiler.h"
 #include "config.h"
 
@@ -36,7 +36,7 @@ class StateFile final {
 
 	const std::string path_utf8;
 
-	TimerEvent timer_event;
+	FarTimerEvent timer_event;
 
 	Partition &partition;
 

src/client/Client.hxx

@@ -25,7 +25,7 @@
 #include "command/CommandListBuilder.hxx"
 #include "tag/Mask.hxx"
 #include "event/FullyBufferedSocket.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 #include "util/Compiler.h"
 
 #include <boost/intrusive/link_mode.hpp>
@@ -54,7 +54,7 @@ class Client final
 	  public boost::intrusive::list_base_hook<boost::intrusive::tag<Partition>,
 						  boost::intrusive::link_mode<boost::intrusive::normal_link>>,
 	  public boost::intrusive::list_base_hook<boost::intrusive::link_mode<boost::intrusive::normal_link>> {
-	TimerEvent timeout_event;
+	CoarseTimerEvent timeout_event;
 
 	Partition *partition;
 

src/db/update/InotifyQueue.hxx

@@ -20,7 +20,7 @@
 #ifndef MPD_INOTIFY_QUEUE_HXX
 #define MPD_INOTIFY_QUEUE_HXX
 
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 
 #include <list>
 #include <string>
@@ -32,7 +32,7 @@ class InotifyQueue final {
 
 	std::list<std::string> queue;
 
-	TimerEvent delay_event;
+	CoarseTimerEvent delay_event;
 
 public:
 	InotifyQueue(EventLoop &_loop, UpdateService &_update) noexcept

src/event/Chrono.hxx

@@ -25,7 +25,7 @@
 namespace Event {
 
 /**
- * The clock used by class #EventLoop and class #TimerEvent.
+ * The clock used by classes #EventLoop, #CoarseTimerEvent and #FineTimerEvent.
  */
 using Clock = std::chrono::steady_clock;
 

src/event/CoarseTimerEvent.hxx

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * 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.
+ */
+
+#pragma once
+
+#include "TimerEvent.hxx"
+
+/**
+ * This class invokes a callback function after a certain amount of
+ * time.  Use Schedule() to start the timer or Cancel() to cancel it.
+ *
+ * Unlike #FineTimerEvent, this class has a granularity of about 1
+ * second, and is optimized for timeouts between 1 and 60 seconds
+ * which are often canceled before they expire (i.e. optimized for
+ * fast insertion and deletion, at the cost of granularity).
+ *
+ * This class is not thread-safe, all methods must be called from the
+ * thread that runs the #EventLoop, except where explicitly documented
+ * as thread-safe.
+ */
+using CoarseTimerEvent = TimerEvent;
+// TODO: implement

src/event/FarTimerEvent.hxx

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * 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.
+ */
+
+#pragma once
+
+#include "FineTimerEvent.hxx"
+
+/**
+ * A coarse timer event which schedules far into the future.  Use this
+ * when you need a coarse resolution, but the supported time span of
+ * #CoarseTimerEvent is not enough.  For example, a good use case is
+ * timers which fire only every few minutes and do periodic cleanup.
+ *
+ * Right now, this is just an alias for #FineTimerEvent.  This class
+ * supports arbitrary time spans, but uses a high-resolution timer.
+ * Eventually, we may turn this into a timer wheel with minute
+ * resolution.
+ */
+using FarTimerEvent = FineTimerEvent;

src/event/FineTimerEvent.hxx

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2007-2021 CM4all GmbH
+ * 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.
+ */
+
+#pragma once
+
+#include "TimerEvent.hxx"
+
+/**
+ * This class invokes a callback function after a certain amount of
+ * time.  Use Schedule() to start the timer or Cancel() to cancel it.
+ *
+ * Unlike #CoarseTimerEvent, this class uses a high-resolution timer,
+ * but at the cost of more expensive insertion and deletion.
+ *
+ * This class is not thread-safe, all methods must be called from the
+ * thread that runs the #EventLoop, except where explicitly documented
+ * as thread-safe.
+ */
+using FineTimerEvent = TimerEvent;
+// TODO: implement

src/event/MultiSocketMonitor.hxx

@@ -21,7 +21,7 @@
 #define MPD_MULTI_SOCKET_MONITOR_HXX
 
 #include "IdleEvent.hxx"
-#include "TimerEvent.hxx"
+#include "FineTimerEvent.hxx"
 #include "SocketEvent.hxx"
 #include "event/Features.h"
 
@@ -92,7 +92,8 @@ class MultiSocketMonitor
 
 	IdleEvent idle_event;
 
-	TimerEvent timeout_event;
+	// TODO: switch to CoarseTimerEvent?  ... not yet because the ALSA plugin needs exact timeouts
+	FineTimerEvent timeout_event;
 
 	/**
 	 * DispatchSockets() should be called.

src/lib/curl/Global.hxx

@@ -31,7 +31,7 @@
 #define CURL_GLOBAL_HXX
 
 #include "Multi.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 #include "event/DeferEvent.hxx"
 
 class CurlSocket;
@@ -45,7 +45,7 @@ class CurlGlobal final {
 
 	DeferEvent defer_read_info;
 
-	TimerEvent timeout_event;
+	CoarseTimerEvent timeout_event;
 
 public:
 	explicit CurlGlobal(EventLoop &_loop);

src/lib/nfs/Connection.hxx

@@ -22,7 +22,7 @@
 
 #include "Cancellable.hxx"
 #include "event/SocketEvent.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 #include "event/DeferEvent.hxx"
 #include "util/Compiler.h"
 
@@ -95,7 +95,7 @@ class NfsConnection {
 
 	SocketEvent socket_event;
 	DeferEvent defer_new_lease;
-	TimerEvent mount_timeout_event;
+	CoarseTimerEvent mount_timeout_event;
 
 	std::string server, export_name;
 

src/lib/systemd/Watchdog.hxx

@@ -30,7 +30,7 @@
 #ifndef SYSTEMD_WATCHDOG_HXX
 #define SYSTEMD_WATCHDOG_HXX
 
-#include "event/TimerEvent.hxx"
+#include "event/FineTimerEvent.hxx"
 
 namespace Systemd {
 
@@ -40,7 +40,7 @@ namespace Systemd {
  * not enabled, this class does nothing.
  */
 class Watchdog {
-	TimerEvent timer;
+	FineTimerEvent timer;
 
 	Event::Duration interval;
 

src/output/plugins/AlsaOutputPlugin.cxx

@@ -38,6 +38,7 @@
 #include "util/StringView.hxx"
 #include "event/MultiSocketMonitor.hxx"
 #include "event/InjectEvent.hxx"
+#include "event/FineTimerEvent.hxx"
 #include "event/Call.hxx"
 #include "Log.hxx"
 
@@ -64,7 +65,7 @@ class AlsaOutput final
 	 * generating silence if Play() doesn't get called soon enough
 	 * to avoid the xrun.
 	 */
-	TimerEvent silence_timer;
+	FineTimerEvent silence_timer;
 
 	PeriodClock throttle_silence_log;
 

src/storage/plugins/NfsStorage.cxx

@@ -33,7 +33,7 @@
 #include "event/Loop.hxx"
 #include "event/Call.hxx"
 #include "event/InjectEvent.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 #include "util/ASCII.hxx"
 #include "util/StringCompare.hxx"
 
@@ -62,7 +62,7 @@ class NfsStorage final
 	NfsConnection *connection;
 
 	InjectEvent defer_connect;
-	TimerEvent reconnect_timer;
+	CoarseTimerEvent reconnect_timer;
 
 	Mutex mutex;
 	Cond cond;

src/zeroconf/AvahiPoll.cxx

@@ -19,7 +19,7 @@
 
 #include "AvahiPoll.hxx"
 #include "event/SocketEvent.hxx"
-#include "event/TimerEvent.hxx"
+#include "event/CoarseTimerEvent.hxx"
 #include "time/Convert.hxx"
 
 static unsigned
@@ -77,7 +77,7 @@ private:
 };
 
 struct AvahiTimeout final {
-	TimerEvent timer;
+	CoarseTimerEvent timer;
 
 	const AvahiTimeoutCallback callback;
 	void *const userdata;