Avert race condition between window attachment and buffer swap

* java/org/gnu/emacs/EmacsView.java (swapBuffers): Synchronize
such that code cannot execute between the bitmap's being loaded
and being transferred to surfaceView.
(onDetachedFromWindow): Recycle bitmap after the surface view is
reset.

* java/org/gnu/emacs/EmacsWindow.java (recreateActivity):

* src/android.c (android_init_emacs_window)
(android_recreate_activity):

* src/androidfns.c (Fandroid_recreate_activity)
(syms_of_androidfns): New functions for debugging window
attachment.

* src/androidgui.h: Update prototypes.

java/org/gnu/emacs/EmacsView.java

@@ -456,7 +456,6 @@ else if (child.getVisibility () != GONE)
   {
     Canvas canvas;
     Rect damageRect;
-    Bitmap bitmap;
 
     /* Make sure this function is called only from the Emacs
        thread.  */
@@ -474,11 +473,12 @@ else if (child.getVisibility () != GONE)
     damageRect = damageRegion.getBounds ();
     damageRegion.setEmpty ();
 
-    bitmap = getBitmap ();
-
-    /* Transfer the bitmap to the surface view, then invalidate
-       it.  */
-    surfaceView.setBitmap (bitmap, damageRect);
+    synchronized (this)
+      {
+	/* Transfer the bitmap to the surface view, then invalidate
+	   it.  */
+	surfaceView.setBitmap (bitmap, damageRect);
+      }
   }
 
   @Override
@@ -724,16 +724,19 @@ else if (child.getVisibility () != GONE)
   public synchronized void
   onDetachedFromWindow ()
   {
+    Bitmap savedBitmap;
+
+    savedBitmap = bitmap;
     isAttachedToWindow = false;
+    bitmap = null;
+    canvas = null;
+
+    surfaceView.setBitmap (null, null);
 
     /* Recycle the bitmap and call GC.  */
 
-    if (bitmap != null)
-      bitmap.recycle ();
-
-    bitmap = null;
-    canvas = null;
-    surfaceView.setBitmap (null, null);
+    if (savedBitmap != null)
+      savedBitmap.recycle ();
 
     /* Collect the bitmap storage; it could be large.  */
     Runtime.getRuntime ().gc ();

java/org/gnu/emacs/EmacsWindow.java

@@ -1784,4 +1784,32 @@ else if (type.equals (ClipDescription.MIMETYPE_TEXT_URILIST))
 
     return true;
   }
+
+
+
+  /* Miscellaneous functions for debugging graphics code.  */
+
+  /* Recreate the activity to which this window is attached, if any.
+     This is nonfunctional on Android 2.3.7 and earlier.  */
+
+  public void
+  recreateActivity ()
+  {
+    final EmacsWindowAttachmentManager.WindowConsumer attached;
+
+    attached = this.attached;
+
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
+      return;
+
+    view.post (new Runnable () {
+	@Override
+	public void
+	run ()
+	{
+	  if (attached instanceof EmacsActivity)
+	    ((EmacsActivity) attached).recreate ();
+	}
+      });
+  }
 };

src/android.c

@@ -111,6 +111,7 @@ struct android_emacs_window
   jmethodID set_dont_focus_on_map;
   jmethodID define_cursor;
   jmethodID damage_rect;
+  jmethodID recreate_activity;
 };
 
 struct android_emacs_cursor
@@ -1802,12 +1803,12 @@ android_init_emacs_window (void)
   FIND_METHOD (set_dont_accept_focus, "setDontAcceptFocus", "(Z)V");
   FIND_METHOD (define_cursor, "defineCursor",
 	       "(Lorg/gnu/emacs/EmacsCursor;)V");
-
   /* In spite of the declaration of this function being located within
      EmacsDrawable, the ID of the `damage_rect' method is retrieved
      from EmacsWindow, which avoids virtual function dispatch within
      android_damage_window.  */
   FIND_METHOD (damage_rect, "damageRect", "(IIII)V");
+  FIND_METHOD (recreate_activity, "recreateActivity", "()V");
 #undef FIND_METHOD
 }
 
@@ -6638,6 +6639,24 @@ android_request_storage_access (void)
   android_exception_check ();
 }
 
+/* Recreate the activity to which WINDOW is attached to debug graphics
+   code executed in response to window attachment.  */
+
+void
+android_recreate_activity (android_window window)
+{
+  jobject object;
+  jmethodID method;
+
+  object = android_resolve_handle (window, ANDROID_HANDLE_WINDOW);
+  method = window_class.recreate_activity;
+
+  (*android_java_env)->CallNonvirtualVoidMethod (android_java_env, object,
+						 window_class.class,
+						 method);
+  android_exception_check ();
+}
+
 
 
 /* The thread from which a query against a thread is currently being

src/androidfns.c

@@ -3164,6 +3164,24 @@ android_set_preeditarea (struct window *w, int x, int y)
 				     y + w->phys_cursor_height);
 }
 
+
+
+/* Debugging.  */
+
+DEFUN ("android-recreate-activity", Fandroid_recreate_activity,
+       Sandroid_recreate_activity, 0, 0, "",
+       doc: /* Recreate the activity attached to the current frame.
+This function exists for debugging purposes and is of no interest to
+users.  */)
+  (void)
+{
+  struct frame *f;
+
+  f = decode_window_system_frame (Qnil);
+  android_recreate_activity (FRAME_ANDROID_WINDOW (f));
+  return Qnil;
+}
+
 #endif /* !ANDROID_STUBIFY */
 
 
@@ -3550,6 +3568,7 @@ language to be US English if LANGUAGE is empty.  */);
   defsubr (&Sandroid_request_directory_access);
   defsubr (&Sandroid_external_storage_available_p);
   defsubr (&Sandroid_request_storage_access);
+  defsubr (&Sandroid_recreate_activity);
 
   tip_timer = Qnil;
   staticpro (&tip_timer);

src/androidgui.h

@@ -708,6 +708,7 @@ extern void android_translate_coordinates (android_window, int,
 extern int android_wc_lookup_string (android_key_pressed_event *,
 				     wchar_t *, int, int *,
 				     enum android_lookup_status *);
+extern void android_recreate_activity (android_window);
 extern void android_update_ic (android_window, ptrdiff_t, ptrdiff_t,
 			       ptrdiff_t, ptrdiff_t);
 extern void android_reset_ic (android_window, enum android_ic_mode);