From d17043dcb49d4f060349a8bd58abcddcf3bac9a2 Mon Sep 17 00:00:00 2001
From: Romain Guy <romainguy@google.com>
Date: Tue, 19 Feb 2013 14:12:55 -0800
Subject: [PATCH] Show Dalvik stack trace if an exception happens at draw time
 External bug: http://code.google.com/p/android/issues/detail?id=49379

Drawing was previously wrapped in a try/finally block which was silently
swallowing user code exceptions. For instance, if a View throws a
NullPointerException in its onDraw() method, the previous implementation
would silently crash in native code.

This change extracts the section that builds display lists into a new
method that does not contain any try/finally block.

In addition, this change logs any exception thrown while drawing
display lists.

Change-Id: I0abffa4c9183d41aac8b0f8442813e56b957f08f
---
 core/java/android/view/HardwareRenderer.java | 52 ++++++++------------
 1 file changed, 21 insertions(+), 31 deletions(-)

diff --git a/core/java/android/view/HardwareRenderer.java b/core/java/android/view/HardwareRenderer.java
index c6e145f2fbefd..7929112d8d64a 100644
--- a/core/java/android/view/HardwareRenderer.java
+++ b/core/java/android/view/HardwareRenderer.java
@@ -441,16 +441,6 @@ public abstract class HardwareRenderer {
     abstract boolean draw(View view, View.AttachInfo attachInfo, HardwareDrawCallbacks callbacks,
             Rect dirty);
 
-    /**
-     * Creates a new display list that can be used to record batches of
-     * drawing operations.
-     *
-     * @return A new display list.
-     */
-    public DisplayList createDisplayList() {
-        return createDisplayList(null);
-    }
-
     /**
      * Creates a new display list that can be used to record batches of
      * drawing operations.
@@ -1356,31 +1346,25 @@ public abstract class HardwareRenderer {
 
                     dirty = beginFrame(canvas, dirty, surfaceState);
 
+                    DisplayList displayList = buildDisplayList(view, canvas);
+
                     int saveCount = 0;
                     int status = DisplayList.STATUS_DONE;
 
                     try {
-                        view.mRecreateDisplayList = (view.mPrivateFlags & View.PFLAG_INVALIDATED)
-                                == View.PFLAG_INVALIDATED;
-                        view.mPrivateFlags &= ~View.PFLAG_INVALIDATED;
-
-                        long buildDisplayListStartTime = startBuildDisplayListProfiling();
-                        canvas.clearLayerUpdates();
-
-                        DisplayList displayList = buildDisplayList(view);
                         status = prepareFrame(dirty);
 
                         saveCount = canvas.save();
                         callbacks.onHardwarePreDraw(canvas);
 
-                        endBuildDisplayListProfiling(buildDisplayListStartTime);
-
                         if (displayList != null) {
                             status = drawDisplayList(attachInfo, canvas, displayList, status);
                         } else {
                             // Shouldn't reach here
                             view.draw(canvas);
                         }
+                    } catch (Exception e) {
+                        Log.e(LOG_TAG, "An error has occurred while drawing:", e);
                     } finally {
                         callbacks.onHardwarePostDraw(canvas);
                         canvas.restoreToCount(saveCount);
@@ -1408,6 +1392,23 @@ public abstract class HardwareRenderer {
             return false;
         }
 
+        private DisplayList buildDisplayList(View view, HardwareCanvas canvas) {
+            view.mRecreateDisplayList = (view.mPrivateFlags & View.PFLAG_INVALIDATED)
+                    == View.PFLAG_INVALIDATED;
+            view.mPrivateFlags &= ~View.PFLAG_INVALIDATED;
+
+            long buildDisplayListStartTime = startBuildDisplayListProfiling();
+            canvas.clearLayerUpdates();
+
+            Trace.traceBegin(Trace.TRACE_TAG_VIEW, "getDisplayList");
+            DisplayList displayList = view.getDisplayList();
+            Trace.traceEnd(Trace.TRACE_TAG_VIEW);
+
+            endBuildDisplayListProfiling(buildDisplayListStartTime);
+
+            return displayList;
+        }
+
         abstract void drawProfileData(View.AttachInfo attachInfo);
 
         private Rect beginFrame(HardwareCanvas canvas, Rect dirty, int surfaceState) {
@@ -1455,17 +1456,6 @@ public abstract class HardwareRenderer {
             }
         }
 
-        private static DisplayList buildDisplayList(View view) {
-            DisplayList displayList;
-            Trace.traceBegin(Trace.TRACE_TAG_VIEW, "getDisplayList");
-            try {
-                displayList = view.getDisplayList();
-            } finally {
-                Trace.traceEnd(Trace.TRACE_TAG_VIEW);
-            }
-            return displayList;
-        }
-
         private int prepareFrame(Rect dirty) {
             int status;
             Trace.traceBegin(Trace.TRACE_TAG_VIEW, "prepareFrame");