Fix bug #6408393 Character corruption is caused when locale is changed

- free the TextLayoutCache on Locale change

- also free TextLayoutCache when memory is low

Change-Id: I39a37ac8ec3c292cfb1c0eea4bb41ff71897d089

Author: Fabrice Di Meglio

core/java/android/app/ActivityThread.java

@@ -2639,6 +2639,7 @@ final void handleResumeActivity(IBinder token, boolean clearHide, boolean isForw
                     if (DEBUG_CONFIGURATION) Slog.v(TAG, "Resuming activity "
                             + r.activityInfo.name + " with newConfig " + r.newConfig);
                     performConfigurationChanged(r.activity, r.newConfig);
+                    freeTextLayoutCachesIfNeeded(r.activity.mCurrentConfig.diff(r.newConfig));
                     r.newConfig = null;
                 }
                 if (localLOGV) Slog.v(TAG, "Resuming " + r + " with isForward="
@@ -2955,6 +2956,7 @@ private void updateVisibility(ActivityClientRecord r, boolean show) {
                     if (DEBUG_CONFIGURATION) Slog.v(TAG, "Updating activity vis "
                             + r.activityInfo.name + " with new config " + r.newConfig);
                     performConfigurationChanged(r.activity, r.newConfig);
+                    freeTextLayoutCachesIfNeeded(r.activity.mCurrentConfig.diff(r.newConfig));
                     r.newConfig = null;
                 }
             } else {
@@ -3669,6 +3671,7 @@ final Configuration applyCompatConfiguration() {
     final void handleConfigurationChanged(Configuration config, CompatibilityInfo compat) {
 
         ArrayList<ComponentCallbacks2> callbacks = null;
+        int configDiff = 0;
 
         synchronized (mPackages) {
             if (mPendingConfiguration != null) {
@@ -3693,6 +3696,7 @@ final void handleConfigurationChanged(Configuration config, CompatibilityInfo co
             if (!mConfiguration.isOtherSeqNewer(config) && compat == null) {
                 return;
             }
+            configDiff = mConfiguration.diff(config);
             mConfiguration.updateFrom(config);
             config = applyCompatConfiguration();
             callbacks = collectComponentCallbacksLocked(false, config);
@@ -3701,6 +3705,8 @@ final void handleConfigurationChanged(Configuration config, CompatibilityInfo co
         // Cleanup hardware accelerated stuff
         WindowManagerImpl.getDefault().trimLocalMemory();
 
+        freeTextLayoutCachesIfNeeded(configDiff);
+
         if (callbacks != null) {
             final int N = callbacks.size();
             for (int i=0; i<N; i++) {
@@ -3709,6 +3715,17 @@ final void handleConfigurationChanged(Configuration config, CompatibilityInfo co
         }
     }
 
+    final void freeTextLayoutCachesIfNeeded(int configDiff) {
+        if (configDiff != 0) {
+            // Ask text layout engine to free its caches if there is a locale change
+            boolean hasLocaleConfigChange = ((configDiff & ActivityInfo.CONFIG_LOCALE) != 0);
+            if (hasLocaleConfigChange) {
+                Canvas.freeTextLayoutCaches();
+                if (DEBUG_CONFIGURATION) Slog.v(TAG, "Cleared TextLayout Caches");
+            }
+        }
+    }
+
     final void handleActivityConfigurationChanged(IBinder token) {
         ActivityClientRecord r = mActivities.get(token);
         if (r == null || r.activity == null) {
@@ -3719,6 +3736,8 @@ final void handleActivityConfigurationChanged(IBinder token) {
                 + r.activityInfo.name);
 
         performConfigurationChanged(r.activity, mCompatConfiguration);
+
+        freeTextLayoutCachesIfNeeded(r.activity.mCurrentConfig.diff(mCompatConfiguration));
     }
 
     final void handleProfilerControl(boolean start, ProfilerControlData pcd, int profileType) {
@@ -3821,6 +3840,9 @@ final void handleLowMemory() {
         // Ask graphics to free up as much as possible (font/image caches)
         Canvas.freeCaches();
 
+        // Ask text layout engine to free also as much as possible
+        Canvas.freeTextLayoutCaches();
+
         BinderInternal.forceGc("mem");
     }
 

core/jni/android/graphics/Canvas.cpp

@@ -69,7 +69,11 @@ class SkCanvasGlue {
         SkImageRef_GlobalPool::SetRAMUsed(0);
         SkGraphics::PurgeFontCache();
     }
-    
+
+    static void freeTextLayoutCaches(JNIEnv* env, jobject) {
+        TextLayoutEngine::getInstance().purgeCaches();
+    }
+
     static jboolean isOpaque(JNIEnv* env, jobject jcanvas) {
         NPE_CHECK_RETURN_ZERO(env, jcanvas);
         SkCanvas* canvas = GraphicsJNI::getNativeCanvas(env, jcanvas);
@@ -986,7 +990,9 @@ static JNINativeMethod gCanvasMethods[] = {
         (void*) SkCanvasGlue::drawTextOnPath__StringPathFFPaint},
     {"native_drawPicture", "(II)V", (void*) SkCanvasGlue::drawPicture},
 
-    {"freeCaches", "()V", (void*) SkCanvasGlue::freeCaches}
+    {"freeCaches", "()V", (void*) SkCanvasGlue::freeCaches},
+
+    {"freeTextLayoutCaches", "()V", (void*) SkCanvasGlue::freeTextLayoutCaches}
 };
 
 ///////////////////////////////////////////////////////////////////////////////

core/jni/android/graphics/TextLayoutCache.cpp

@@ -991,4 +991,11 @@ sp<TextLayoutValue> TextLayoutEngine::getValue(const SkPaint* paint, const jchar
     return value;
 }
 
+void TextLayoutEngine::purgeCaches() {
+#if USE_TEXT_LAYOUT_CACHE
+    mTextLayoutCache->clear();
+#endif
+}
+
+
 } // namespace android

core/jni/android/graphics/TextLayoutCache.h

@@ -309,6 +309,9 @@ class TextLayoutEngine : public Singleton<TextLayoutEngine> {
 
     sp<TextLayoutValue> getValue(const SkPaint* paint, const jchar* text, jint start,
             jint count, jint contextCount, jint dirFlags);
+
+    void purgeCaches();
+
 private:
     TextLayoutCache* mTextLayoutCache;
     TextLayoutShaper* mShaper;

graphics/java/android/graphics/Canvas.java

@@ -1617,6 +1617,13 @@ public void drawPicture(Picture picture, Rect dst) {
      */
     public static native void freeCaches();
 
+    /**
+     * Free up text layout caches
+     *
+     * @hide
+     */
+    public static native void freeTextLayoutCaches();
+
     private static native int initRaster(int nativeBitmapOrZero);
     private static native void native_setBitmap(int nativeCanvas, int bitmap);
     private static native int native_saveLayer(int nativeCanvas, RectF bounds,