Add compat path for restore underflow

bug:19829784

Change-Id: Ia761664208ab80c055ca11174db3ddc74457b92b

5 files changed, 26 insertions, 19 deletions

diff --git a/core/java/android/view/DisplayListCanvas.java b/core/java/android/view/DisplayListCanvas.java
index 3caf6f07c891..ec8f802a179f 100644
--- a/core/java/android/view/DisplayListCanvas.java
+++ b/core/java/android/view/DisplayListCanvas.java
@@ -48,7 +48,6 @@ public class DisplayListCanvas extends Canvas {
     private int mWidth;
     private int mHeight;
 
-
     static DisplayListCanvas obtain(@NonNull RenderNode node) {
         if (node == null) throw new IllegalArgumentException("node cannot be null");
         DisplayListCanvas canvas = sPool.acquire();
diff --git a/core/java/android/view/RenderNode.java b/core/java/android/view/RenderNode.java
index ef98bbcd35f4..236cfefd9718 100644
--- a/core/java/android/view/RenderNode.java
+++ b/core/java/android/view/RenderNode.java
@@ -240,12 +240,7 @@ public class RenderNode {
      * @see #start(int, int)
      * @see #isValid()
      */
-    public void end(DisplayListCanvas endCanvas) {
-        if (!(endCanvas instanceof DisplayListCanvas)) {
-            throw new IllegalArgumentException("Passed an invalid canvas to end!");
-        }
-
-        DisplayListCanvas canvas = (DisplayListCanvas) endCanvas;
+    public void end(DisplayListCanvas canvas) {
         canvas.onPostDraw();
         long renderNodeData = canvas.finishRecording();
         nSetDisplayListData(mNativeRenderNode, renderNodeData);
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index a69384af8d91..386362353f22 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -3582,6 +3582,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
             // of whether a layout was requested on that View.
             sIgnoreMeasureCache = targetSdkVersion < KITKAT;
 
+            Canvas.sCompatibilityRestore = targetSdkVersion < MNC;
+
             sCompatibilityDone = true;
         }
     }
diff --git a/core/jni/android_graphics_Canvas.cpp b/core/jni/android_graphics_Canvas.cpp
index 4c08b4b056fe..a2c16097b2bf 100644
--- a/core/jni/android_graphics_Canvas.cpp
+++ b/core/jni/android_graphics_Canvas.cpp
@@ -86,20 +86,26 @@ static jint saveLayerAlpha(JNIEnv* env, jobject, jlong canvasHandle, jfloat l, j
     return static_cast<jint>(get_canvas(canvasHandle)->saveLayerAlpha(l, t, r, b, alpha, flags));
 }
 
-static void restore(JNIEnv* env, jobject, jlong canvasHandle) {
+static void restore(JNIEnv* env, jobject, jlong canvasHandle, jboolean throwOnUnderflow) {
     Canvas* canvas = get_canvas(canvasHandle);
     if (canvas->getSaveCount() <= 1) {  // cannot restore anymore
-        doThrowISE(env, "Underflow in restore - more restores than saves");
-        return;
+        if (throwOnUnderflow) {
+            doThrowISE(env, "Underflow in restore - more restores than saves");
+        }
+        return; // compat behavior - return without throwing
     }
     canvas->restore();
 }
 
-static void restoreToCount(JNIEnv* env, jobject, jlong canvasHandle, jint restoreCount) {
+static void restoreToCount(JNIEnv* env, jobject, jlong canvasHandle, jint restoreCount,
+        jboolean throwOnUnderflow) {
     Canvas* canvas = get_canvas(canvasHandle);
     if (restoreCount < 1 || restoreCount > canvas->getSaveCount()) {
-        doThrowIAE(env, "Underflow in restoreToCount - more restores than saves");
-        return;
+        if (throwOnUnderflow) {
+            doThrowIAE(env, "Underflow in restoreToCount - more restores than saves");
+            return;
+        }
+        restoreCount = 1; // compat behavior - restore as far as possible
     }
     canvas->restoreToCount(restoreCount);
 }
@@ -661,8 +667,8 @@ static JNINativeMethod gMethods[] = {
     {"native_saveLayer","(JFFFFJI)I", (void*) CanvasJNI::saveLayer},
     {"native_saveLayerAlpha","(JFFFFII)I", (void*) CanvasJNI::saveLayerAlpha},
     {"native_getSaveCount","(J)I", (void*) CanvasJNI::getSaveCount},
-    {"native_restore","(J)V", (void*) CanvasJNI::restore},
-    {"native_restoreToCount","(JI)V", (void*) CanvasJNI::restoreToCount},
+    {"native_restore","(JZ)V", (void*) CanvasJNI::restore},
+    {"native_restoreToCount","(JIZ)V", (void*) CanvasJNI::restoreToCount},
     {"native_getCTM", "(JJ)V", (void*)CanvasJNI::getCTM},
     {"native_setMatrix","(JJ)V", (void*) CanvasJNI::setMatrix},
     {"native_concat","(JJ)V", (void*) CanvasJNI::concat},
diff --git a/graphics/java/android/graphics/Canvas.java b/graphics/java/android/graphics/Canvas.java
index 150f1950a81f..48afcbfde5d0 100644
--- a/graphics/java/android/graphics/Canvas.java
+++ b/graphics/java/android/graphics/Canvas.java
@@ -45,6 +45,8 @@ import javax.microedition.khronos.opengles.GL;
  * Canvas and Drawables</a> developer guide.</p></div>
  */
 public class Canvas {
+    /** @hide */
+    public static boolean sCompatibilityRestore = false;
 
     /**
      * Should only be assigned in constructors (or setBitmap if software canvas),
@@ -557,7 +559,8 @@ public class Canvas {
      * an error to call restore() more times than save() was called.
      */
     public void restore() {
-        native_restore(mNativeCanvasWrapper);
+        boolean throwOnUnderflow = !sCompatibilityRestore || !isHardwareAccelerated();
+        native_restore(mNativeCanvasWrapper, throwOnUnderflow);
     }
 
     /**
@@ -582,7 +585,8 @@ public class Canvas {
      * @param saveCount The save level to restore to.
      */
     public void restoreToCount(int saveCount) {
-        native_restoreToCount(mNativeCanvasWrapper, saveCount);
+        boolean throwOnUnderflow = !sCompatibilityRestore || !isHardwareAccelerated();
+        native_restoreToCount(mNativeCanvasWrapper, saveCount, throwOnUnderflow);
     }
 
     /**
@@ -1988,9 +1992,10 @@ public class Canvas {
     private static native int native_saveLayerAlpha(long nativeCanvas, float l,
                                                     float t, float r, float b,
                                                     int alpha, int layerFlags);
-    private static native void native_restore(long canvasHandle);
+    private static native void native_restore(long canvasHandle, boolean tolerateUnderflow);
     private static native void native_restoreToCount(long canvasHandle,
-                                                     int saveCount);
+                                                     int saveCount,
+                                                     boolean tolerateUnderflow);
     private static native int native_getSaveCount(long canvasHandle);
 
     private static native void native_translate(long canvasHandle,