2003/12/27 01:03:53

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

diff --git a/src/org/xwt/Scheduler.java b/src/org/xwt/Scheduler.java
index 79fba3c..d61ad55 100644 (file)
--- a/src/org/xwt/Scheduler.java
+++ b/src/org/xwt/Scheduler.java
@@ -8,23 +8,41 @@ import org.xwt.util.*;
 /** Implements cooperative multitasking */
 public class Scheduler {
 
+    // FIXME: prepending events messes with keysate -- make a "no re-ordering" invariant?
+
     // Public API Exposed to org.xwt /////////////////////////////////////////////////
 
     private static Scheduler singleton;
-    public static abstract class Task { public abstract void perform(); }
+    public static interface Task { public abstract void perform() throws Exception; }
+
+    /** adds a task to the back of the queue */
     public static void add(Task t) { singleton.runnable.append(t); }
-    public static void init() {
-        if (singleton != null) return;
-        singleton = Platform.getScheduler();
-        singleton.run();
+
+    /** adds a task to the front of the queue (guaranteed to run next) */
+    public static void addAtFront(Task t) { singleton.runnable.prepend(t); }
+
+    public static void init() { if (singleton == null) (singleton = Platform.getScheduler()).run(); }
+
+    private static Task current = null;
+    public static Task current() { return current; }
+
+    /** synchronizd so that we can safely call it from an event-delivery thread, in-context */
+    public static synchronized void renderAll() {
+        for(int i=0; i<Surface.allSurfaces.size(); i++) {
+            Surface s = ((Surface)Surface.allSurfaces.elementAt(i));
+            do { s.render(); } while(s.abort);
+        }
     }
 
+    
 
     // API which must be supported by subclasses /////////////////////////////////////
 
     /**
-     *  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.
+     *  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(); }
     protected Scheduler() { }
@@ -35,15 +53,30 @@ public class Scheduler {
     protected static Queue runnable = new Queue(50);
     public void defaultRun() {
         while(true) {
-            Task t = (Task)runnable.remove(true);
+            current = (Task)runnable.remove(true);
             try {
-                t.perform();
-                // FEATURE: be smarter about this
-                Surface.renderAll();
+                synchronized(this) {
+                    for(int i=0; i<Surface.allSurfaces.size(); i++) {
+                        Surface s = (Surface)Surface.allSurfaces.elementAt(i);
+                        if (current instanceof JSFunction) {
+                            s._mousex = Integer.MAX_VALUE;
+                            s._mousey = Integer.MAX_VALUE;
+                        } else {
+                            s._mousex = s.mousex;
+                            s._mousey = s.mousey;
+                        }
+                    }
+                    current.perform();
+                }
+                renderAll();
+            } catch (JSExn e) {
+                Log.log(Scheduler.class, "a JavaScript thread spawned with xwt.thread() threw an exception:");
+                Log.log(Scheduler.class, e);
             } catch (Exception e) {
-                Log.log(Scheduler.class, "Task threw an exception: " + e);
+                Log.log(Scheduler.class, "a Task threw an exception which was caught by the scheduler:");
                 Log.log(Scheduler.class, e);
             }
+            // if an Error is thrown it will cause the engine to quit
         }
     }
 }