Fix Bug 606 - New AWT threading implementation breaks .. ; Fix GLAutoDrawable multi-threading w/ proper pattern (hope so)

Considering code changes and remarks:
  3ed491213f8f7f05d7b9866b50d764370d8ff5f6
  1a91ec5c8b6fd9d9db7bc115569c369fe7b38e9b
  3334a924309a9361a448d69bc707d4cce416b430
  4f27bcecf7484dc041551f52a5c49e2884cb3867

It seems necessary to have

- recursive locking employed for all semantic actions which changes drawable & context (and the Window resource)

- to avoid deadlock, we have to ensure the locked code segment will not spawn
  off to another thread, or a thread holds the lock, spawns of an action requiring the lock. .. sure

- other read-only methods (flags, ..) shall at least utilize a safe local copy of a volatile field
  if further use to produce the result is necessary.

- flags like sendReshape require to be volatile to guarantee it's being processed

Patch impacts: AWT/SWT GLCanvas, GLAutoDrawableBase [and it's specializations]
and hopefully closes any loopholes of missing a cache hit, etc.

If you review this and find optimizations, i.e. removing a lock due to semantics etc,
don't hold back and discuss it, please.

1 files changed, 10 insertions, 7 deletions

diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
index 0c01aa676..090c5fe69 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableHelper.java
@@ -189,8 +189,9 @@ public class GLDrawableHelper {
    */
   public final void dispose(GLAutoDrawable drawable) {
     synchronized(listenersLock) {
-        for (int i=0; i < listeners.size(); i++) {
-          listeners.get(i).dispose(drawable);
+        final ArrayList<GLEventListener> _listeners = listeners;
+        for (int i=0; i < _listeners.size(); i++) {
+          _listeners.get(i).dispose(drawable);
         }
     }
   }
@@ -209,8 +210,9 @@ public class GLDrawableHelper {
   /** The default init action to be called once after ctx is being created @ 1st makeCurrent(). */
   public final void init(GLAutoDrawable drawable) {
     synchronized(listenersLock) {
-        for (int i=0; i < listeners.size(); i++) {
-          final GLEventListener listener = listeners.get(i) ;
+        final ArrayList<GLEventListener> _listeners = listeners;
+        for (int i=0; i < _listeners.size(); i++) {
+          final GLEventListener listener = _listeners.get(i) ;
 
           // If make current ctx, invoked by invokGL(..), results in a new ctx, init gets called.
           // This may happen not just for initial setup, but for ctx recreation due to resource change (drawable/window),
@@ -232,8 +234,9 @@ public class GLDrawableHelper {
   }
   private final void displayImpl(GLAutoDrawable drawable) {
       synchronized(listenersLock) {
-          for (int i=0; i < listeners.size(); i++) {
-            final GLEventListener listener = listeners.get(i) ;
+          final ArrayList<GLEventListener> _listeners = listeners;
+          for (int i=0; i < _listeners.size(); i++) {
+            final GLEventListener listener = _listeners.get(i) ;
             // GLEventListener may need to be init, 
             // in case this one is added after the realization of the GLAutoDrawable
             init( listener, drawable, true /* sendReshape */) ; 
@@ -324,7 +327,7 @@ public class GLDrawableHelper {
     }
   }
 
-  public final boolean isExternalAnimatorRunning() {
+  public final boolean isAnimatorRunningOnOtherThread() {
     return ( null != animatorCtrl ) ? animatorCtrl.isStarted() && animatorCtrl.getThread() != Thread.currentThread() : false ;
   }