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      1 /*
      2  * Copyright (C) 2006 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.app;
     18 
     19 import android.os.Build;
     20 import android.os.GraphicsEnvironment;
     21 import android.os.Trace;
     22 import android.util.ArrayMap;
     23 
     24 import com.android.internal.os.ClassLoaderFactory;
     25 
     26 import dalvik.system.PathClassLoader;
     27 
     28 import java.util.Collection;
     29 
     30 /** @hide */
     31 public class ApplicationLoaders {
     32     public static ApplicationLoaders getDefault() {
     33         return gApplicationLoaders;
     34     }
     35 
     36     ClassLoader getClassLoader(String zip, int targetSdkVersion, boolean isBundled,
     37                                String librarySearchPath, String libraryPermittedPath,
     38                                ClassLoader parent, String classLoaderName) {
     39         // For normal usage the cache key used is the same as the zip path.
     40         return getClassLoader(zip, targetSdkVersion, isBundled, librarySearchPath,
     41                               libraryPermittedPath, parent, zip, classLoaderName);
     42     }
     43 
     44     private ClassLoader getClassLoader(String zip, int targetSdkVersion, boolean isBundled,
     45                                        String librarySearchPath, String libraryPermittedPath,
     46                                        ClassLoader parent, String cacheKey,
     47                                        String classLoaderName) {
     48         /*
     49          * This is the parent we use if they pass "null" in.  In theory
     50          * this should be the "system" class loader; in practice we
     51          * don't use that and can happily (and more efficiently) use the
     52          * bootstrap class loader.
     53          */
     54         ClassLoader baseParent = ClassLoader.getSystemClassLoader().getParent();
     55 
     56         synchronized (mLoaders) {
     57             if (parent == null) {
     58                 parent = baseParent;
     59             }
     60 
     61             /*
     62              * If we're one step up from the base class loader, find
     63              * something in our cache.  Otherwise, we create a whole
     64              * new ClassLoader for the zip archive.
     65              */
     66             if (parent == baseParent) {
     67                 ClassLoader loader = mLoaders.get(cacheKey);
     68                 if (loader != null) {
     69                     return loader;
     70                 }
     71 
     72                 Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     73 
     74                 ClassLoader classloader = ClassLoaderFactory.createClassLoader(
     75                         zip,  librarySearchPath, libraryPermittedPath, parent,
     76                         targetSdkVersion, isBundled, classLoaderName);
     77 
     78                 Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     79 
     80                 Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "setLayerPaths");
     81                 GraphicsEnvironment.getInstance().setLayerPaths(
     82                         classloader, librarySearchPath, libraryPermittedPath);
     83                 Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     84 
     85                 mLoaders.put(cacheKey, classloader);
     86                 return classloader;
     87             }
     88 
     89             Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, zip);
     90             ClassLoader loader = ClassLoaderFactory.createClassLoader(
     91                     zip, null, parent, classLoaderName);
     92             Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
     93             return loader;
     94         }
     95     }
     96 
     97     /**
     98      * Creates a classloader for the WebView APK and places it in the cache of loaders maintained
     99      * by this class. This is used in the WebView zygote, where its presence in the cache speeds up
    100      * startup and enables memory sharing.
    101      */
    102     public ClassLoader createAndCacheWebViewClassLoader(String packagePath, String libsPath,
    103                                                         String cacheKey) {
    104         // The correct paths are calculated by WebViewZygote in the system server and passed to
    105         // us here. We hardcode the other parameters: WebView always targets the current SDK,
    106         // does not need to use non-public system libraries, and uses the base classloader as its
    107         // parent to permit usage of the cache.
    108         // The cache key is passed separately to enable the stub WebView to be cached under the
    109         // stub's APK path, when the actual package path is the donor APK.
    110         return getClassLoader(packagePath, Build.VERSION.SDK_INT, false, libsPath, null, null,
    111                               cacheKey, null /* classLoaderName */);
    112     }
    113 
    114     /**
    115      * Adds a new path the classpath of the given loader.
    116      * @throws IllegalStateException if the provided class loader is not a {@link PathClassLoader}.
    117      */
    118     void addPath(ClassLoader classLoader, String dexPath) {
    119         if (!(classLoader instanceof PathClassLoader)) {
    120             throw new IllegalStateException("class loader is not a PathClassLoader");
    121         }
    122         final PathClassLoader baseDexClassLoader = (PathClassLoader) classLoader;
    123         baseDexClassLoader.addDexPath(dexPath);
    124     }
    125 
    126     /**
    127      * @hide
    128      */
    129     void addNative(ClassLoader classLoader, Collection<String> libPaths) {
    130         if (!(classLoader instanceof PathClassLoader)) {
    131             throw new IllegalStateException("class loader is not a PathClassLoader");
    132         }
    133         final PathClassLoader baseDexClassLoader = (PathClassLoader) classLoader;
    134         baseDexClassLoader.addNativePath(libPaths);
    135     }
    136 
    137     private final ArrayMap<String, ClassLoader> mLoaders = new ArrayMap<>();
    138 
    139     private static final ApplicationLoaders gApplicationLoaders = new ApplicationLoaders();
    140 }
    141