1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.webkit; 18 19 import android.os.Build; 20 import android.os.StrictMode; 21 import android.os.SystemProperties; 22 import android.util.Log; 23 24 import dalvik.system.PathClassLoader; 25 26 /** 27 * Top level factory, used creating all the main WebView implementation classes. 28 */ 29 class WebViewFactory { 30 // Default Provider factory class name. 31 // TODO: When the Chromium powered WebView is ready, it should be the default factory class. 32 private static final String DEFAULT_WEBVIEW_FACTORY = "android.webkit.WebViewClassic$Factory"; 33 private static final String CHROMIUM_WEBVIEW_FACTORY = 34 "com.android.webviewchromium.WebViewChromiumFactoryProvider"; 35 private static final String CHROMIUM_WEBVIEW_JAR = "/system/framework/webviewchromium.jar"; 36 37 private static final String LOGTAG = "WebViewFactory"; 38 39 private static final boolean DEBUG = false; 40 41 // Cache the factory both for efficiency, and ensure any one process gets all webviews from the 42 // same provider. 43 private static WebViewFactoryProvider sProviderInstance; 44 private static final Object sProviderLock = new Object(); 45 getProvider()46 static WebViewFactoryProvider getProvider() { 47 synchronized (sProviderLock) { 48 // For now the main purpose of this function (and the factory abstraction) is to keep 49 // us honest and minimize usage of WebViewClassic internals when binding the proxy. 50 if (sProviderInstance != null) return sProviderInstance; 51 52 // For debug builds, we allow a system property to specify that we should use the 53 // Chromium powered WebView. This enables us to switch between implementations 54 // at runtime. For user (release) builds, don't allow this. 55 if (Build.IS_DEBUGGABLE && SystemProperties.getBoolean("webview.use_chromium", false)) { 56 StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads(); 57 try { 58 sProviderInstance = loadChromiumProvider(); 59 if (DEBUG) Log.v(LOGTAG, "Loaded Chromium provider: " + sProviderInstance); 60 } finally { 61 StrictMode.setThreadPolicy(oldPolicy); 62 } 63 } 64 65 if (sProviderInstance == null) { 66 if (DEBUG) Log.v(LOGTAG, "Falling back to default provider: " 67 + DEFAULT_WEBVIEW_FACTORY); 68 sProviderInstance = getFactoryByName(DEFAULT_WEBVIEW_FACTORY, 69 WebViewFactory.class.getClassLoader()); 70 if (sProviderInstance == null) { 71 if (DEBUG) Log.v(LOGTAG, "Falling back to explicit linkage"); 72 sProviderInstance = new WebViewClassic.Factory(); 73 } 74 } 75 return sProviderInstance; 76 } 77 } 78 79 // TODO: This allows us to have the legacy and Chromium WebView coexist for development 80 // and side-by-side testing. After transition, remove this when no longer required. loadChromiumProvider()81 private static WebViewFactoryProvider loadChromiumProvider() { 82 ClassLoader clazzLoader = new PathClassLoader(CHROMIUM_WEBVIEW_JAR, null, 83 WebViewFactory.class.getClassLoader()); 84 return getFactoryByName(CHROMIUM_WEBVIEW_FACTORY, clazzLoader); 85 } 86 getFactoryByName(String providerName, ClassLoader loader)87 private static WebViewFactoryProvider getFactoryByName(String providerName, 88 ClassLoader loader) { 89 try { 90 if (DEBUG) Log.v(LOGTAG, "attempt to load class " + providerName); 91 Class<?> c = Class.forName(providerName, true, loader); 92 if (DEBUG) Log.v(LOGTAG, "instantiating factory"); 93 return (WebViewFactoryProvider) c.newInstance(); 94 } catch (ClassNotFoundException e) { 95 Log.e(LOGTAG, "error loading " + providerName, e); 96 } catch (IllegalAccessException e) { 97 Log.e(LOGTAG, "error loading " + providerName, e); 98 } catch (InstantiationException e) { 99 Log.e(LOGTAG, "error loading " + providerName, e); 100 } 101 return null; 102 } 103 } 104