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