Simplify ViewManagerOnDemandReactPackage.getViewManagerNames to return Collection

Summary:
This way we can avoid unnecessary ArrayList copies.

Changelog: [Android][Changed] Generalized the return type of ViewManagerOnDemandReactPackage.getViewManagerNames

Reviewed By: nlutsenko

Differential Revision: D36131516

fbshipit-source-id: 6a42c76cadbcce4c3720875d80062e1ee237bc2f

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

@@ -14,6 +14,7 @@ import com.facebook.react.module.model.ReactModuleInfo;
 import com.facebook.react.module.model.ReactModuleInfoProvider;
 import com.facebook.react.uimanager.ViewManager;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -89,18 +90,18 @@ public class CompositeReactPackage implements ViewManagerOnDemandReactPackage, R
 
   /** {@inheritDoc} */
   @Override
-  public List<String> getViewManagerNames(ReactApplicationContext reactContext) {
+  public Collection<String> getViewManagerNames(ReactApplicationContext reactContext) {
     Set<String> uniqueNames = new HashSet<>();
     for (ReactPackage reactPackage : mChildReactPackages) {
       if (reactPackage instanceof ViewManagerOnDemandReactPackage) {
-        List<String> names =
+        Collection<String> names =
             ((ViewManagerOnDemandReactPackage) reactPackage).getViewManagerNames(reactContext);
         if (names != null) {
           uniqueNames.addAll(names);
         }
       }
     }
-    return new ArrayList<>(uniqueNames);
+    return uniqueNames;
   }
 
   /** {@inheritDoc} */

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

@@ -37,8 +37,8 @@ import com.facebook.react.uimanager.UIManagerModule;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.react.uimanager.ViewManagerResolver;
 import com.facebook.systrace.Systrace;
+import java.util.Collection;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
 /**
@@ -184,7 +184,7 @@ public class CoreModulesPackage extends TurboReactPackage implements ReactPackag
               }
 
               @Override
-              public List<String> getViewManagerNames() {
+              public Collection<String> getViewManagerNames() {
                 return mReactInstanceManager.getViewManagerNames();
               }
             };

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

@@ -159,7 +159,7 @@ public class ReactInstanceManager {
   private final JavaScriptExecutorFactory mJavaScriptExecutorFactory;
 
   // See {@code ReactInstanceManagerBuilder} for description of all flags here.
-  private @Nullable List<String> mViewManagerNames = null;
+  private @Nullable Collection<String> mViewManagerNames = null;
   private final @Nullable JSBundleLoader mBundleLoader;
   private final @Nullable String mJSMainModulePath; /* path to JS bundle root on Metro */
   private final List<ReactPackage> mPackages;
@@ -962,9 +962,9 @@ public class ReactInstanceManager {
     return null;
   }
 
-  public @Nullable List<String> getViewManagerNames() {
+  public Collection<String> getViewManagerNames() {
     Systrace.beginSection(TRACE_TAG_REACT_JAVA_BRIDGE, "ReactInstanceManager.getViewManagerNames");
-    List<String> viewManagerNames = mViewManagerNames;
+    Collection<String> viewManagerNames = mViewManagerNames;
     if (viewManagerNames != null) {
       return viewManagerNames;
     }
@@ -972,7 +972,7 @@ public class ReactInstanceManager {
     synchronized (mReactContextLock) {
       context = (ReactApplicationContext) getCurrentReactContext();
       if (context == null || !context.hasActiveReactInstance()) {
-        return null;
+        return Collections.emptyList();
       }
     }
 
@@ -985,7 +985,7 @@ public class ReactInstanceManager {
               .arg("Package", reactPackage.getClass().getSimpleName())
               .flush();
           if (reactPackage instanceof ViewManagerOnDemandReactPackage) {
-            List<String> names =
+            Collection<String> names =
                 ((ViewManagerOnDemandReactPackage) reactPackage).getViewManagerNames(context);
             if (names != null) {
               uniqueNames.addAll(names);
@@ -994,7 +994,7 @@ public class ReactInstanceManager {
           SystraceMessage.endSection(TRACE_TAG_REACT_JAVA_BRIDGE).flush();
         }
         Systrace.endSection(TRACE_TAG_REACT_JAVA_BRIDGE);
-        mViewManagerNames = new ArrayList<>(uniqueNames);
+        mViewManagerNames = uniqueNames;
       }
       return mViewManagerNames;
     }

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

@@ -10,15 +10,14 @@ package com.facebook.react;
 import androidx.annotation.Nullable;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.uimanager.ViewManager;
-import java.util.List;
+import java.util.Collection;
 
 public interface ViewManagerOnDemandReactPackage {
   /**
    * Provides a list of names of ViewManagers with which these modules can be accessed from JS.
    * Typically, this is ViewManager.getName().
    */
-  @Nullable
-  List<String> getViewManagerNames(ReactApplicationContext reactContext);
+  Collection<String> getViewManagerNames(ReactApplicationContext reactContext);
   /**
    * Creates and returns a ViewManager with a specific name {@param viewManagerName}. It's up to an
    * implementing package how to interpret the name.

ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModuleConstantsHelper.java

@@ -12,6 +12,7 @@ import static com.facebook.systrace.Systrace.TRACE_TAG_REACT_JAVA_BRIDGE;
 import androidx.annotation.Nullable;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.systrace.SystraceMessage;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
@@ -33,7 +34,7 @@ import java.util.Map;
    */
   /* package */ static Map<String, Object> createConstants(ViewManagerResolver resolver) {
     Map<String, Object> constants = UIManagerModuleConstants.getConstants();
-    constants.put("ViewManagerNames", resolver.getViewManagerNames());
+    constants.put("ViewManagerNames", new ArrayList<>(resolver.getViewManagerNames()));
     constants.put("LazyViewManagersEnabled", true);
     return constants;
   }

ReactAndroid/src/main/java/com/facebook/react/uimanager/ViewManagerResolver.java

@@ -7,7 +7,7 @@
 
 package com.facebook.react.uimanager;
 
-import java.util.List;
+import java.util.Collection;
 import javax.annotation.Nullable;
 
 /** Enables lazy discovery of a specific {@link ViewManager} by its name. */
@@ -22,5 +22,5 @@ public interface ViewManagerResolver {
   /**
    * Provides a list of view manager names to register in JS as {@code UIManager.ViewManagerName}
    */
-  List<String> getViewManagerNames();
+  Collection<String> getViewManagerNames();
 }