(svn r25354) -Add: link graph schedule and typedefs for LinkGraph and related classes

src/linkgraph/linkgraphschedule.h

@@ -0,0 +1,83 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD 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, version 2.
+ * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file linkgraphschedule.h Declaration of link graph schedule used for cargo distribution. */
+
+#ifndef LINKGRAPHSCHEDULE_H
+#define LINKGRAPHSCHEDULE_H
+
+#include "linkgraph.h"
+
+class LinkGraphJob;
+
+/**
+ * A handler doing "something" on a link graph component. It must not keep any
+ * state as it is called concurrently from different threads.
+ */
+class ComponentHandler {
+public:
+	/**
+	 * Destroy the handler. Must be given due to virtual Run.
+	 */
+	virtual ~ComponentHandler() {}
+
+	/**
+	 * Run the handler. A link graph handler must not read or write any data
+	 * outside the given component as that would create a potential desync.
+	 * @param job Link graph component to run the handler on.
+	 */
+	virtual void Run(LinkGraphJob &job) const = 0;
+};
+
+class LinkGraphSchedule {
+private:
+	LinkGraphSchedule();
+	~LinkGraphSchedule();
+	typedef std::list<LinkGraph *> GraphList;
+	typedef std::list<LinkGraphJob *> JobList;
+	friend const SaveLoad *GetLinkGraphScheduleDesc();
+
+protected:
+	ComponentHandler *handlers[1]; ///< Handlers to be run for each job.
+	GraphList schedule;            ///< Queue for new jobs.
+	JobList running;               ///< Currently running jobs.
+
+	void SpawnThread(LinkGraphJob *job);
+	void JoinThread(LinkGraphJob *job);
+
+public:
+	/* This is a tick where not much else is happening, so a small lag might go unnoticed. */
+	static const uint SPAWN_JOIN_TICK = 21; ///< Tick when jobs are spawned or joined every day.
+
+	static LinkGraphSchedule *Instance();
+	static void Run(void *j);
+	static void Clear();
+
+	void SpawnNext();
+	void JoinNext();
+	void SpawnAll();
+
+	/**
+	 * Queue a link graph for execution.
+	 * @param lg Link graph to be queued.
+	 */
+	void Queue(LinkGraph *lg)
+	{
+		assert(LinkGraph::Get(lg->index) == lg);
+		this->schedule.push_back(lg);
+	}
+
+	/**
+	 * Remove a link graph from the execution queue.
+	 * @param lg Link graph to be removed.
+	 */
+	void Unqueue(LinkGraph *lg) { this->schedule.remove(lg); }
+};
+
+#endif /* LINKGRAPHSCHEDULE_H */