Trigger GC and drop compiled code on low memory

Reviewed By: astreet

Differential Revision: D2658693

fb-gh-sync-id: 8cba49b67ac45a2dbf8b4c9c404d6fb9c97693f6

ReactAndroid/src/main/java/com/facebook/react/MemoryPressureRouter.java

@@ -0,0 +1,93 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.react;
+
+import javax.annotation.Nullable;
+
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.content.ComponentCallbacks2;
+import android.content.Context;
+import android.content.res.Configuration;
+import android.os.Build;
+
+import com.facebook.react.bridge.CatalystInstance;
+import com.facebook.react.bridge.MemoryPressure;
+import com.facebook.react.bridge.ReactContext;
+
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_BACKGROUND;
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_MODERATE;
+import static android.content.ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL;
+
+/**
+ * Translates and routes memory pressure events to the current catalyst instance.
+ */
+public class MemoryPressureRouter {
+  // Trigger this by sending an intent to your activity with adb shell:
+  // am start -a "com.facebook.catalyst.ACTION_TRIM_MEMORY" --activity-single-top -n <activity>
+  private static final String ACTION_TRIM_MEMORY ="com.facebook.catalyst.ACTION_TRIM_MEMORY";
+
+  private @Nullable CatalystInstance mCatalystInstance;
+  private final ComponentCallbacks2 mCallbacks = new ComponentCallbacks2() {
+    @Override
+    public void onTrimMemory(int level) {
+      trimMemory(level);
+    }
+
+    @Override
+    public void onConfigurationChanged(Configuration newConfig) {
+    }
+
+    @Override
+    public void onLowMemory() {
+    }
+  };
+
+  @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+  public static boolean handleDebugIntent(Activity activity, String action) {
+    switch (action) {
+      case ACTION_TRIM_MEMORY:
+        simulateTrimMemory(activity, TRIM_MEMORY_MODERATE);
+        break;
+      default:
+        return false;
+    }
+
+    return true;
+  }
+
+  MemoryPressureRouter(Context context) {
+    context.getApplicationContext().registerComponentCallbacks(mCallbacks);
+  }
+
+  public void onNewReactContextCreated(ReactContext reactContext) {
+    mCatalystInstance = reactContext.getCatalystInstance();
+  }
+
+  public void onReactInstanceDestroyed() {
+    mCatalystInstance = null;
+  }
+
+  public void destroy(Context context) {
+    context.getApplicationContext().unregisterComponentCallbacks(mCallbacks);
+  }
+
+  private void trimMemory(int level) {
+    if (level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
+      dispatchMemoryPressure(MemoryPressure.CRITICAL);
+    } else if (level >= TRIM_MEMORY_BACKGROUND || level == TRIM_MEMORY_RUNNING_CRITICAL) {
+      dispatchMemoryPressure(MemoryPressure.MODERATE);
+    }
+  }
+
+  private void dispatchMemoryPressure(MemoryPressure level) {
+    if (mCatalystInstance != null) {
+      mCatalystInstance.handleMemoryPressure(level);
+    }
+  }
+
+  private static void simulateTrimMemory(Activity activity, int level) {
+    activity.getApplication().onTrimMemory(level);
+    activity.onTrimMemory(level);
+  }
+}

ReactAndroid/src/main/java/com/facebook/react/ReactInstanceManagerImpl.java

@@ -100,6 +100,7 @@ import com.facebook.systrace.Systrace;
       new ConcurrentLinkedQueue<>();
   private volatile boolean mHasStartedCreatingInitialContext = false;
   private final UIImplementationProvider mUIImplementationProvider;
+  private final MemoryPressureRouter mMemoryPressureRouter;
 
   private final ReactInstanceDevCommandsHandler mDevInterface =
       new ReactInstanceDevCommandsHandler() {
@@ -215,6 +216,7 @@ import com.facebook.systrace.Systrace;
     mBridgeIdleDebugListener = bridgeIdleDebugListener;
     mLifecycleState = initialLifecycleState;
     mUIImplementationProvider = uiImplementationProvider;
+    mMemoryPressureRouter = new MemoryPressureRouter(applicationContext);
   }
 
   @Override
@@ -400,6 +402,7 @@ import com.facebook.systrace.Systrace;
   public void onDestroy() {
     UiThreadUtil.assertOnUiThread();
 
+    mMemoryPressureRouter.destroy(mApplicationContext);
     if (mUseDeveloperSupport) {
       mDevSupportManager.setDevSupportEnabled(false);
     }
@@ -539,6 +542,7 @@ import com.facebook.systrace.Systrace;
 
     catalystInstance.initialize();
     mDevSupportManager.onNewReactContextCreated(reactContext);
+    mMemoryPressureRouter.onNewReactContextCreated(reactContext);
     moveReactContextToCurrentLifecycleState(reactContext);
 
     for (ReactRootView rootView : mAttachedRootViews) {
@@ -591,6 +595,7 @@ import com.facebook.systrace.Systrace;
     }
     reactContext.onDestroy();
     mDevSupportManager.onReactInstanceDestroyed(reactContext);
+    mMemoryPressureRouter.onReactInstanceDestroyed();
   }
 
   /**

ReactAndroid/src/main/java/com/facebook/react/bridge/CatalystInstance.java

@@ -9,8 +9,6 @@
 
 package com.facebook.react.bridge;
 
-import javax.annotation.Nullable;
-
 import java.util.Collection;
 
 import com.facebook.react.bridge.queue.CatalystQueueConfiguration;
@@ -49,6 +47,8 @@ public interface CatalystInstance {
   <T extends NativeModule> T getNativeModule(Class<T> nativeModuleInterface);
   Collection<NativeModule> getNativeModules();
 
+  void handleMemoryPressure(MemoryPressure level);
+
   /**
    * Adds a idle listener for this Catalyst instance. The listener will receive notifications
    * whenever the bridge transitions from idle to busy and vice-versa, where the busy state is

ReactAndroid/src/main/java/com/facebook/react/bridge/CatalystInstanceImpl.java

@@ -314,6 +314,11 @@ public class CatalystInstanceImpl implements CatalystInstance {
     return mJavaRegistry.getAllModules();
   }
 
+  @Override
+  public void handleMemoryPressure(MemoryPressure level) {
+    Assertions.assertNotNull(mBridge).handleMemoryPressure(level);
+  }
+
   /**
    * Adds a idle listener for this Catalyst instance. The listener will receive notifications
    * whenever the bridge transitions from idle to busy and vice-versa, where the busy state is

ReactAndroid/src/main/java/com/facebook/react/bridge/MemoryPressure.java

@@ -0,0 +1,8 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.react.bridge;
+
+public enum MemoryPressure {
+  MODERATE,
+  CRITICAL
+}

ReactAndroid/src/main/java/com/facebook/react/bridge/ReactBridge.java

@@ -56,6 +56,19 @@ public class ReactBridge extends Countable {
     super.dispose();
   }
 
+  public void handleMemoryPressure(MemoryPressure level) {
+    switch (level) {
+      case MODERATE:
+        handleMemoryPressureModerate();
+        break;
+      case CRITICAL:
+        handleMemoryPressureCritical();
+        break;
+      default:
+        throw new IllegalArgumentException("Unknown level: " + level);
+    }
+  }
+
   private native void initialize(
       JavaScriptExecutor jsExecutor,
       ReactCallback callback,
@@ -72,4 +85,6 @@ public class ReactBridge extends Countable {
   public native boolean supportsProfiling();
   public native void startProfiler(String title);
   public native void stopProfiler(String title, String filename);
+  private native void handleMemoryPressureModerate();
+  private native void handleMemoryPressureCritical();
 }