Add a menu item for HMR

Summary:
cc martinbigio
Closes https://github.com/facebook/react-native/pull/5092

Reviewed By: svcscm

Differential Revision: D2807241

Pulled By: mkonicek

fb-gh-sync-id: e4418eeb4944d795f30f94be94b80648b4d7034c

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevInternalSettings.java

@@ -34,6 +34,7 @@ public class DevInternalSettings implements
   private static final String PREFS_ANIMATIONS_DEBUG_KEY = "animations_debug";
   private static final String PREFS_RELOAD_ON_JS_CHANGE_KEY = "reload_on_js_change";
   private static final String PREFS_INSPECTOR_DEBUG_KEY = "inspector_debug";
+  private static final String PREFS_HOT_MODULE_REPLACEMENT_KEY = "hot_module_replacement";
 
   private final SharedPreferences mPreferences;
   private final DevSupportManager mDebugManager;
@@ -77,6 +78,14 @@ public class DevInternalSettings implements
     }
   }
 
+  public boolean isHotModuleReplacementEnabled() {
+    return mPreferences.getBoolean(PREFS_HOT_MODULE_REPLACEMENT_KEY, false);
+  }
+
+  public void setHotModuleReplacementEnabled(boolean enabled) {
+    mPreferences.edit().putBoolean(PREFS_HOT_MODULE_REPLACEMENT_KEY, enabled).apply();
+  }
+
   public boolean isReloadOnJSChangeEnabled() {
     return mPreferences.getBoolean(PREFS_RELOAD_ON_JS_CHANGE_KEY, false);
   }

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevServerHelper.java

@@ -25,7 +25,6 @@ import com.facebook.common.logging.FLog;
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.common.ReactConstants;
-
 import com.squareup.okhttp.Call;
 import com.squareup.okhttp.Callback;
 import com.squareup.okhttp.ConnectionPool;
@@ -33,6 +32,7 @@ import com.squareup.okhttp.OkHttpClient;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.ResponseBody;
+
 import okio.Okio;
 import okio.Sink;
 
@@ -55,7 +55,7 @@ public class DevServerHelper {
   private static final String DEVICE_LOCALHOST = "localhost:8081";
 
   private static final String BUNDLE_URL_FORMAT =
-      "http://%s/%s.bundle?platform=android&dev=%s";
+      "http://%s/%s.bundle?platform=android&dev=%s&hot=%s";
   private static final String SOURCE_MAP_URL_FORMAT =
       BUNDLE_URL_FORMAT.replaceFirst("\\.bundle", ".map");
   private static final String LAUNCH_CHROME_DEVTOOLS_COMMAND_URL_FORMAT =
@@ -120,12 +120,19 @@ public class DevServerHelper {
   }
 
   /**
-   * @return whether we should enabled dev mode or not when requesting JS bundles.
+   * @return whether we should enable dev mode when requesting JS bundles.
    */
   private boolean getDevMode() {
     return mSettings.isJSDevModeEnabled();
   }
 
+  /**
+   * @return whether we should enabled HMR when requesting JS bundles.
+   */
+  private boolean getHMR() {
+    return mSettings.isHotModuleReplacementEnabled();
+  }
+
   /**
    * @return the host to use when connecting to the bundle server.
    */
@@ -160,15 +167,15 @@ public class DevServerHelper {
     return Build.FINGERPRINT.contains("generic");
   }
 
-  private static String createBundleURL(String host, String jsModulePath, boolean devMode) {
+  private static String createBundleURL(String host, String jsModulePath, boolean devMode, boolean hmr) {
-    return String.format(Locale.US, BUNDLE_URL_FORMAT, host, jsModulePath, devMode);
+    return String.format(Locale.US, BUNDLE_URL_FORMAT, host, jsModulePath, devMode, hmr);
   }
 
   public void downloadBundleFromURL(
       final BundleDownloadCallback callback,
       final String jsModulePath,
       final File outputFile) {
-    final String bundleURL = createBundleURL(getDebugServerHost(), jsModulePath, getDevMode());
+    final String bundleURL = createBundleURL(getDebugServerHost(), jsModulePath, getDevMode(), getHMR());
     Request request = new Request.Builder()
         .url(bundleURL)
         .build();
@@ -354,17 +361,17 @@ public class DevServerHelper {
   }
 
   public String getSourceMapUrl(String mainModuleName) {
-    return String.format(Locale.US, SOURCE_MAP_URL_FORMAT, getDebugServerHost(), mainModuleName, getDevMode());
+    return String.format(Locale.US, SOURCE_MAP_URL_FORMAT, getDebugServerHost(), mainModuleName, getDevMode(), getHMR());
   }
 
   public String getSourceUrl(String mainModuleName) {
-    return String.format(Locale.US, BUNDLE_URL_FORMAT, getDebugServerHost(), mainModuleName, getDevMode());
+    return String.format(Locale.US, BUNDLE_URL_FORMAT, getDebugServerHost(), mainModuleName, getDevMode(), getHMR());
   }
 
   public String getJSBundleURLForRemoteDebugging(String mainModuleName) {
     // The host IP we use when connecting to the JS bundle server from the emulator is not the
     // same as the one needed to connect to the same server from the Chrome proxy running on the
     // host itself.
-    return createBundleURL(getHostForJSProxy(), mainModuleName, getDevMode());
+    return createBundleURL(getHostForJSProxy(), mainModuleName, getDevMode(), getHMR());
   }
 }

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManager.java

@@ -262,6 +262,17 @@ public class DevSupportManager implements NativeModuleCallExceptionHandler {
             handleReloadJS();
           }
         });
+    options.put(
+            mDevSettings.isHotModuleReplacementEnabled()
+                    ? mApplicationContext.getString(R.string.catalyst_hot_module_replacement_off)
+                    : mApplicationContext.getString(R.string.catalyst_hot_module_replacement),
+            new DevOptionHandler() {
+              @Override
+              public void onOptionSelected() {
+                mDevSettings.setHotModuleReplacementEnabled(!mDevSettings.isHotModuleReplacementEnabled());
+                handleReloadJS();
+              }
+            });
     options.put(
         mDevSettings.isReloadOnJSChangeEnabled()
             ? mApplicationContext.getString(R.string.catalyst_live_reload_off)

ReactAndroid/src/main/res/devsupport/values/strings.xml

@@ -3,6 +3,8 @@
   <string name="catalyst_reloadjs" project="catalyst" translatable="false">Reload JS</string>
   <string name="catalyst_debugjs" project="catalyst" translatable="false">Debug in Chrome</string>
   <string name="catalyst_debugjs_off" project="catalyst" translatable="false">Stop Chrome Debugging</string>
+  <string name="catalyst_hot_module_replacement" project="catalyst" translatable="false">Enable Hot Module Replacement</string>
+  <string name="catalyst_hot_module_replacement_off" project="catalyst" translatable="false">Disable Hot Module Replacement</string>
   <string name="catalyst_live_reload" project="catalyst" translatable="false">Enable Live Reload</string>
   <string name="catalyst_live_reload_off" project="catalyst" translatable="false">Disable Live Reload</string>
   <string name="catalyst_perf_monitor" project="catalyst" translatable="false">Enable Perf Monitor</string>