WebViewFactory.java revision b7d5cbc0073e37e6bcb1e496aefb829babde6931
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 17package android.webkit; 18 19import android.os.Build; 20import android.os.StrictMode; 21import android.os.SystemProperties; 22import android.util.AndroidRuntimeException; 23import android.util.Log; 24 25/** 26 * Top level factory, used creating all the main WebView implementation classes. 27 * 28 * @hide 29 */ 30public final class WebViewFactory { 31 private static final boolean DEFAULT_TO_EXPERIMENTAL_WEBVIEW = true; 32 // REMEMBER: property names must be <= 31 chars total. 33 private static final String EXPERIMENTAL_PROPERTY_DEFAULT_OFF = "persist.sys.webview.exp"; 34 private static final String EXPERIMENTAL_PROPERTY_DEFAULT_ON = 35 "persist.sys.webview." + Build.ID; 36 37 // Modify the persisted property name when the new webview is on-by-default, so that any user 38 // setting override only lives as long as that build. 39 private static final String LONG_PROPERTY_NAME = DEFAULT_TO_EXPERIMENTAL_WEBVIEW ? 40 EXPERIMENTAL_PROPERTY_DEFAULT_ON : EXPERIMENTAL_PROPERTY_DEFAULT_OFF; 41 private static final String WEBVIEW_EXPERIMENTAL_PROPERTY = 42 LONG_PROPERTY_NAME.length() > SystemProperties.PROP_NAME_MAX ? 43 LONG_PROPERTY_NAME.substring(0, SystemProperties.PROP_NAME_MAX) : LONG_PROPERTY_NAME; 44 45 private static final String FORCE_PROVIDER_PROPERTY = "webview.force_provider"; 46 private static final String FORCE_PROVIDER_PROPERTY_VALUE_CHROMIUM = "chromium"; 47 private static final String FORCE_PROVIDER_PROPERTY_VALUE_CLASSIC = "classic"; 48 49 // Default Provider factory class name. 50 // TODO: When the Chromium powered WebView is ready, it should be the default factory class. 51 private static final String DEFAULT_WEBVIEW_FACTORY = "android.webkit.WebViewClassic$Factory"; 52 private static final String CHROMIUM_WEBVIEW_FACTORY = 53 "com.android.webview.chromium.WebViewChromiumFactoryProvider"; 54 55 private static final String LOGTAG = "WebViewFactory"; 56 57 private static final boolean DEBUG = false; 58 59 private static class Preloader { 60 static WebViewFactoryProvider sPreloadedProvider; 61 static { 62 try { 63 sPreloadedProvider = getFactoryClass().newInstance(); 64 } catch (Exception e) { 65 Log.w(LOGTAG, "error preloading provider", e); 66 } 67 } 68 } 69 70 // Cache the factory both for efficiency, and ensure any one process gets all webviews from the 71 // same provider. 72 private static WebViewFactoryProvider sProviderInstance; 73 private static final Object sProviderLock = new Object(); 74 75 public static boolean isExperimentalWebViewAvailable() { 76 try { 77 // Pass false so we don't initialize the class at this point, as this will be wasted if 78 // it's not enabled. 79 Class.forName(CHROMIUM_WEBVIEW_FACTORY, false, WebViewFactory.class.getClassLoader()); 80 return true; 81 } catch (ClassNotFoundException e) { 82 return false; 83 } 84 } 85 86 /** @hide */ 87 public static void setUseExperimentalWebView(boolean enable) { 88 SystemProperties.set(WEBVIEW_EXPERIMENTAL_PROPERTY, enable ? "true" : "false"); 89 Log.i(LOGTAG, "Use Experimental WebView changed: " 90 + SystemProperties.get(WebViewFactory.WEBVIEW_EXPERIMENTAL_PROPERTY, "")); 91 } 92 93 /** @hide */ 94 public static boolean useExperimentalWebView() { 95 return SystemProperties.getBoolean(WEBVIEW_EXPERIMENTAL_PROPERTY, 96 DEFAULT_TO_EXPERIMENTAL_WEBVIEW); 97 } 98 99 /** @hide */ 100 public static boolean isUseExperimentalWebViewSet() { 101 return !SystemProperties.get(WEBVIEW_EXPERIMENTAL_PROPERTY).isEmpty(); 102 } 103 104 static WebViewFactoryProvider getProvider() { 105 synchronized (sProviderLock) { 106 // For now the main purpose of this function (and the factory abstraction) is to keep 107 // us honest and minimize usage of WebViewClassic internals when binding the proxy. 108 if (sProviderInstance != null) return sProviderInstance; 109 110 Class<WebViewFactoryProvider> providerClass; 111 try { 112 providerClass = getFactoryClass(); 113 } catch (ClassNotFoundException e) { 114 Log.e(LOGTAG, "error loading provider", e); 115 throw new AndroidRuntimeException(e); 116 } 117 118 // This implicitly loads Preloader even if it wasn't preloaded at boot. 119 if (Preloader.sPreloadedProvider != null && 120 Preloader.sPreloadedProvider.getClass() == providerClass) { 121 sProviderInstance = Preloader.sPreloadedProvider; 122 if (DEBUG) Log.v(LOGTAG, "Using preloaded provider: " + sProviderInstance); 123 return sProviderInstance; 124 } 125 126 // The preloaded provider isn't the one we wanted; construct our own. 127 StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads(); 128 try { 129 sProviderInstance = providerClass.newInstance(); 130 if (DEBUG) Log.v(LOGTAG, "Loaded provider: " + sProviderInstance); 131 return sProviderInstance; 132 } catch (Exception e) { 133 Log.e(LOGTAG, "error instantiating provider", e); 134 throw new AndroidRuntimeException(e); 135 } finally { 136 StrictMode.setThreadPolicy(oldPolicy); 137 } 138 } 139 } 140 141 // We allow a system property to specify that we should use the experimental Chromium powered 142 // WebView. This enables us to switch between implementations at runtime. 143 private static boolean isExperimentalWebViewEnabled() { 144 if (!isExperimentalWebViewAvailable()) return false; 145 String forceProviderName = SystemProperties.get(FORCE_PROVIDER_PROPERTY); 146 if (forceProviderName.isEmpty()) return useExperimentalWebView(); 147 148 Log.i(LOGTAG, String.format("Provider overridden by property: %s=%s", 149 FORCE_PROVIDER_PROPERTY, forceProviderName)); 150 if (forceProviderName.equals(FORCE_PROVIDER_PROPERTY_VALUE_CHROMIUM)) return true; 151 if (forceProviderName.equals(FORCE_PROVIDER_PROPERTY_VALUE_CLASSIC)) return false; 152 Log.e(LOGTAG, String.format("Unrecognized provider: %s", forceProviderName)); 153 return useExperimentalWebView(); 154 } 155 156 private static Class<WebViewFactoryProvider> getFactoryClass() throws ClassNotFoundException { 157 if (isExperimentalWebViewEnabled()) { 158 return (Class<WebViewFactoryProvider>) Class.forName(CHROMIUM_WEBVIEW_FACTORY); 159 } else { 160 return (Class<WebViewFactoryProvider>) Class.forName(DEFAULT_WEBVIEW_FACTORY); 161 } 162 } 163} 164