Fix IllegalArgumentException when dismissing ReactModalHostView

Summary: This diff fixes an IllegalArgumentException when dismissing ReactModalHostView. I wasn't able to reproduce this error because this is likely created by a race condition.

Reviewed By: axe-fb

Differential Revision: D12916787

fbshipit-source-id: b071ffc4c251f2a613bb1270de005def56818376

ReactAndroid/src/main/java/com/facebook/react/views/common/BUCK

@@ -4,6 +4,7 @@ rn_android_library(
     name = "common",
     srcs = glob(["*.java"]),
     provided_deps = [
+        react_native_dep("third-party/java/jsr-305:jsr-305"),
         react_native_dep("third-party/android/support/v4:lib-support-v4"),
     ],
     visibility = [

ReactAndroid/src/main/java/com/facebook/react/views/common/ContextUtils.java

@@ -0,0 +1,37 @@
+package com.facebook.react.views.common;
+
+import android.content.Context;
+import android.content.ContextWrapper;
+import javax.annotation.Nullable;
+
+/**
+ * Class containing static methods involving manipulations of Contexts and their related subclasses.
+ */
+public class ContextUtils {
+
+  /**
+   * Returns the nearest context in the chain (as defined by ContextWrapper.getBaseContext()) which
+   * is an instance of the specified type, or null if one could not be found
+   *
+   * @param context Initial context
+   * @param clazz Class instance to look for
+   * @param <T>
+   * @return the first context which is an instance of the specified class, or null if none exists
+   */
+  public static @Nullable <T> T findContextOfType(
+    @Nullable Context context, Class<? extends T> clazz) {
+    while (!(clazz.isInstance(context))) {
+      if (context instanceof ContextWrapper) {
+        Context baseContext = ((ContextWrapper) context).getBaseContext();
+        if (context == baseContext) {
+          return null;
+        } else {
+          context = baseContext;
+        }
+      } else {
+        return null;
+      }
+    }
+    return (T) context;
+  }
+}

ReactAndroid/src/main/java/com/facebook/react/views/modal/BUCK

@@ -17,6 +17,7 @@ rn_android_library(
         react_native_target("java/com/facebook/react/touch:touch"),
         react_native_target("java/com/facebook/react/uimanager:uimanager"),
         react_native_target("java/com/facebook/react/uimanager/annotations:annotations"),
+        react_native_target("java/com/facebook/react/views/common:common"),
         react_native_target("java/com/facebook/react/views/view:view"),
         react_native_target("res:modal"),
     ],

ReactAndroid/src/main/java/com/facebook/react/views/modal/ReactModalHostView.java

@@ -28,6 +28,7 @@ import com.facebook.react.uimanager.JSTouchDispatcher;
 import com.facebook.react.uimanager.RootView;
 import com.facebook.react.uimanager.UIManagerModule;
 import com.facebook.react.uimanager.events.EventDispatcher;
+import com.facebook.react.views.common.ContextUtils;
 import com.facebook.react.views.view.ReactViewGroup;
 import java.util.ArrayList;
 import javax.annotation.Nullable;
@@ -123,9 +124,11 @@ public class ReactModalHostView extends ViewGroup implements LifecycleEventListe
 
   private void dismiss() {
     if (mDialog != null) {
-      Activity currentActivity = getCurrentActivity();
-      if (mDialog.isShowing() && (currentActivity == null || !currentActivity.isFinishing())) {
-        mDialog.dismiss();
+      if (mDialog.isShowing()) {
+        Activity dialogContext = ContextUtils.findContextOfType(mDialog.getContext(), Activity.class);
+        if (dialogContext == null || !dialogContext.isFinishing()) {
+          mDialog.dismiss();
+        }
       }
       mDialog = null;