Scripting|libcore: Added Scheduler for time-based script execution

doomsday/sdk/libcore/include/de/Scheduler

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+#include "scriptsys/scheduler.h"

doomsday/sdk/libcore/include/de/scriptsys/scheduler.h

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+/** @file scheduler.h  Script scheduling utility.
+ *
+ * @authors Copyright (c) 2015 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * LGPL: http://www.gnu.org/licenses/lgpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 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 Lesser
+ * General Public License for more details. You should have received a copy of
+ * the GNU Lesser General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+#ifndef LIBDENG2_SCHEDULER_H
+#define LIBDENG2_SCHEDULER_H
+
+#include "../libcore.h"
+#include "../Time"
+#include "../String"
+
+namespace de {
+
+class Script;
+class Record;
+
+/**
+ * Script scheduling utility.
+ *
+ * Scheduler owns the parsed scripts, and can be re-run if rewound.
+ */
+class DENG2_PUBLIC Scheduler
+{
+public:
+    Scheduler();
+
+    void clear();
+
+    /**
+     * Sets the execution context, i.e., global namespace for the scripts. All
+     * scripts of the scheduler run in the same context.
+     *
+     * @param context  Global namespace.
+     */
+    void setContext(Record &context);
+
+    /**
+     * Adds a new script to the scheduler.
+     *
+     * @param at          Point in time when the script is to be executed.
+     * @param source      Script source. This will be parsed before the method returns.
+     * @param sourcePath  Path where the source comes from.
+     *
+     * @return Scheduled Script (owned by Scheduler).
+     */
+    Script &addScript(TimeDelta at, String const &source, String const &sourcePath = "");
+
+    /**
+     * Returns the current time of the scheduler.
+     */
+    TimeDelta at() const;
+
+    /**
+     * Rewinds the current time of the Scheduler back to zero.
+     */
+    void rewind();
+
+    /**
+     * Advances the current time of the Schduler and executes any scripts whose
+     * execution time has arrived.
+     *
+     * @param elapsed  Time elapsed since the previous call.
+     */
+    void advanceTime(TimeDelta const &elapsed);
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+} // namespace de
+
+#endif // LIBDENG2_SCHEDULER_H
+

doomsday/sdk/libcore/src/scriptsys/scheduler.cpp

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+/** @file scheduler.cpp  Script scheduling utility.
+ *
+ * @authors Copyright (c) 2015 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * LGPL: http://www.gnu.org/licenses/lgpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 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 Lesser
+ * General Public License for more details. You should have received a copy of
+ * the GNU Lesser General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+#include "de/Scheduler"
+#include "de/Record"
+#include "de/Script"
+#include "de/Process"
+
+#include <queue>
+#include <deque>
+
+namespace de {
+
+DENG2_PIMPL(Scheduler)
+, DENG2_OBSERVES(Record, Deletion)
+{
+    Record *context = nullptr;
+    TimeDelta at = 0.0;
+
+    struct Event {
+        TimeDelta at;
+        Script script;
+
+        Event(TimeDelta at, String const &source, String const &sourcePath)
+            : at(at)
+            , script(source)
+        {
+            script.setPath(sourcePath); // where the source comes from
+        }
+
+        struct Compare {
+            bool operator () (Event const *a, Event const *b) { return a->at > b->at; }
+        };
+    };
+    std::priority_queue<Event *, std::deque<Event *>, Event::Compare> events;
+    QList<Event *> done;
+
+    Instance(Public *i) : Base(i)
+    {}
+
+    ~Instance()
+    {
+        setContext(nullptr);
+        clear();
+    }
+
+    void clear()
+    {
+        while(!events.empty())
+        {
+            delete events.top();
+            events.pop();
+        }
+        qDeleteAll(done);
+        done.clear();
+        rewind();
+    }
+
+    void setContext(Record *rec)
+    {
+        if(context) context->audienceForDeletion() -= this;
+        context = rec;
+        if(context) context->audienceForDeletion() += this;
+    }
+
+    void recordBeingDeleted(Record &record)
+    {
+        if(context == &record)
+        {
+            context = nullptr;
+        }
+    }
+
+    void rewind()
+    {
+        at = 0.0;
+
+        // Restore all the past events into the queue.
+        for(Event *ev : done)
+        {
+            events.push(ev);
+        }
+        done.clear();
+    }
+
+    void advanceTime(TimeDelta const &elapsed)
+    {
+        at += elapsed;
+
+        while(!events.empty())
+        {
+            Event *ev = events.top();
+            if(ev->at > at) break;
+
+            events.pop();
+            done.append(ev);
+
+            // Execute the script in the specified context.
+            Process process(context);
+            process.run(ev->script);
+            process.execute();
+        }
+    }
+};
+
+Scheduler::Scheduler()
+    : d(new Instance(this))
+{}
+
+void Scheduler::clear()
+{
+    d->clear();
+}
+
+void Scheduler::setContext(Record &context)
+{
+    d->setContext(&context);
+}
+
+Script &Scheduler::addScript(TimeDelta at, String const &source, String const &sourcePath)
+{
+    auto *ev = new Instance::Event(at, source, sourcePath);
+    d->events.push(ev);
+    return ev->script;
+}
+
+TimeDelta Scheduler::at() const
+{
+    return d->at;
+}
+
+void Scheduler::rewind()
+{
+    d->rewind();
+}
+
+void Scheduler::advanceTime(TimeDelta const &elapsed)
+{
+    d->advanceTime(elapsed);
+}
+
+} // namespace de