Expose way for native modules to modify JSC context

Reviewed By: svcscm

Differential Revision: D2933197

fb-gh-sync-id: 32eb943ab341804343bbcadd29f0377fccf75de6
shipit-source-id: 32eb943ab341804343bbcadd29f0377fccf75de6

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

@@ -332,6 +332,11 @@ public abstract class BaseJavaModule implements NativeModule {
     return false;
   }
 
+  @Override
+  public void onReactBridgeInitialized(ReactBridge bridge) {
+    // do nothing
+  }
+
   @Override
   public void onCatalystInstanceDestroy() {
     // do nothing

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

@@ -127,6 +127,7 @@ public class CatalystInstanceImpl implements CatalystInstance {
       Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
     }
 
+    mJavaRegistry.notifyReactBridgeInitialized(bridge);
     return bridge;
   }
 

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

@@ -59,6 +59,15 @@ public interface NativeModule {
    */
   boolean canOverrideExistingModule();
 
+  /**
+   * Called on the JS thread after a ReactBridge has been created. This is useful for native modules
+   * that need to do any setup before the JS bundle has been loaded. An example of this would be
+   * installing custom functionality into the JavaScriptCore context.
+   *
+   * @param bridge the ReactBridge instance that has just been created
+   */
+  void onReactBridgeInitialized(ReactBridge bridge);
+
   /**
    * Called before {CatalystInstance#onHostDestroy}
    */

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

@@ -114,6 +114,19 @@ public class NativeModuleRegistry {
     }
   }
 
+  /* package */ void notifyReactBridgeInitialized(ReactBridge bridge) {
+    Systrace.beginSection(
+        Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
+        "NativeModuleRegistry_notifyReactBridgeInitialized");
+    try {
+      for (NativeModule nativeModule : mModuleInstances.values()) {
+        nativeModule.onReactBridgeInitialized(bridge);
+      }
+    } finally {
+      Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
+    }
+  }
+
   public void onBatchComplete() {
     for (int i = 0; i < mBatchCompleteListenerModules.size(); i++) {
       mBatchCompleteListenerModules.get(i).onBatchComplete();

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

@@ -87,4 +87,13 @@ public class ReactBridge extends Countable {
   public native void stopProfiler(String title, String filename);
   private native void handleMemoryPressureModerate();
   private native void handleMemoryPressureCritical();
+
+  /**
+   * This method will return a long representing the underlying JSGlobalContextRef pointer or
+   * 0 (representing NULL) when in Chrome debug mode, and is only useful if passed back through
+   * the JNI to native code that will use it with the JavaScriptCore C API.
+   * **WARNING:** This method is *experimental* and should only be used when no other option is
+   * available. It will likely change in a future release!
+   */
+  public native long getJavaScriptContextNativePtrExperimental();
 }