imported files removed from elsewhere

[org.ibex.core.git] / src / org / ibex / core / Scheduler.java

diff --git a/src/org/ibex/core/Scheduler.java b/src/org/ibex/core/Scheduler.java
new file mode 100644 (file)
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--- /dev/null
+++ b/src/org/ibex/core/Scheduler.java
@@ -0,0 +1,94 @@
+// Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
+package org.ibex.util;
+
+import java.io.IOException;
+
+import org.ibex.js.*;
+import org.ibex.util.*;
+import org.ibex.graphics.*;
+import org.ibex.plat.*;
+
+/** Implements cooperative multitasking */
+public class Scheduler {
+
+    // Public API Exposed to org.ibex /////////////////////////////////////////////////
+
+    private static Scheduler singleton;
+    public static void add(Task t) { Log.debug(Scheduler.class, "scheduling " + t); Scheduler.runnable.append(t); }
+    public static void init() { if (singleton == null) (singleton = Platform.getScheduler()).run(); }
+
+    private static Task current = null;
+
+    private static volatile boolean rendering = false;
+    private static volatile boolean again = false;
+
+    /** synchronizd so that we can safely call it from an event-delivery thread, in-context */
+    public static void renderAll() {
+        if (rendering) { again = true; return; }
+        synchronized(Scheduler.class) {
+            try {
+                rendering = true;
+                do {
+                    // FEATURE: this could be cleaner
+                    again = false;
+                    for(int i=0; i<Surface.allSurfaces.size(); i++) {
+                        Surface s = ((Surface)Surface.allSurfaces.elementAt(i));
+                        do { s.render(); } while(s.abort);
+                    }
+                } while(again);
+            } finally {
+                rendering = false;
+            }
+        }
+    }
+
+    
+
+    // API which must be supported by subclasses /////////////////////////////////////
+
+    /**
+     *  SCHEDULER INVARIANT: all scheduler implementations MUST invoke
+     *  Surface.renderAll() after performing a Task if no tasks remain
+     *  in the queue.  A scheduler may choose to invoke
+     *  Surface.renderAll() more often than that if it so chooses.
+     */
+    public void run() { defaultRun(); }
+    public Scheduler() { }
+
+
+    // Default Implementation //////////////////////////////////////////////////////
+
+    protected static Queue runnable = new Queue(50);
+    public void defaultRun() {
+        while(true) {
+            current = (Task)runnable.remove(true);
+            try {
+                // FIXME hideous
+                synchronized(this) {
+                    for(int i=0; i<Surface.allSurfaces.size(); i++) {
+                        Surface s = (Surface)Surface.allSurfaces.elementAt(i);
+                        if (current instanceof JS) {
+                            s._mousex = Integer.MAX_VALUE;
+                            s._mousey = Integer.MAX_VALUE;
+                        } else {
+                            s._mousex = s.mousex;
+                            s._mousey = s.mousey;
+                        }
+                    }
+                    Log.debug(Scheduler.class, "performing " + current);
+                    current.perform();
+                }
+                renderAll();
+            } catch (JSExn e) {
+                Log.info(Scheduler.class, "a JavaScript thread spawned with ibex.thread() threw an exception:");
+                Log.info(Scheduler.class,e);
+            } catch (Exception e) {
+                Log.info(Scheduler.class, "a Task threw an exception which was caught by the scheduler:");
+                Log.info(Scheduler.class, e);
+            } catch (Throwable t) {
+                t.printStackTrace();
+            }
+            // if an Error is thrown it will cause the engine to quit
+        }
+    }
+}