// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.components.module_installer.builder;
import android.content.Context;
import androidx.annotation.VisibleForTesting;
import org.jni_zero.JNINamespace;
import org.jni_zero.NativeMethods;
import org.chromium.base.BundleUtils;
import org.chromium.base.ContextUtils;
import org.chromium.base.StrictModeContext;
import org.chromium.base.library_loader.LibraryLoader;
import org.chromium.components.module_installer.engine.InstallEngine;
import org.chromium.components.module_installer.engine.InstallListener;
import org.chromium.components.module_installer.util.Timer;
/**
* Represents a feature module. Can be used to install the module, access its interface, etc. See
* {@link ModuleInterface} for how to conveniently create an instance of the module class for a
* specific feature module.
*
* @param <T> The interface of the module
*/
@JNINamespace("module_installer")
public class Module<T> {
private final String mName;
private final Class<T> mInterfaceClass;
private final String mImplClassName;
private ModuleDescriptor mModuleDescriptor;
private Context mContext;
private T mImpl;
private InstallEngine mInstaller;
private boolean mIsNativeLoaded;
/**
* Instantiates a module.
*
* @param name The module's name as used with {@link ModuleInstaller}.
* @param interfaceClass {@link Class} object of the module interface.
* @param implClassName fully qualified class name of the implementation of the module's
* interface.
*/
public Module(String name, Class<T> interfaceClass, String implClassName) {
mName = name;
mInterfaceClass = interfaceClass;
mImplClassName = implClassName;
}
@VisibleForTesting
public InstallEngine getInstallEngine() {
if (mInstaller == null) {
try (Timer timer = new Timer()) {
mInstaller = new ModuleEngine(mImplClassName);
}
}
return mInstaller;
}
@VisibleForTesting
public void setInstallEngine(InstallEngine engine) {
mInstaller = engine;
}
/** Returns true if the module is currently installed and can be accessed. */
public boolean isInstalled() {
try (Timer timer = new Timer()) {
return getInstallEngine().isInstalled(mName);
}
}
/** Requests install of the module. */
public void install(InstallListener listener) {
try (Timer timer = new Timer()) {
assert !isInstalled();
getInstallEngine().install(mName, listener);
}
}
/** Requests deferred install of the module. */
public void installDeferred() {
try (Timer timer = new Timer()) {
getInstallEngine().installDeferred(mName);
}
}
/**
* Returns the implementation of the module interface. Must only be called if the module is
* installed.
*/
public T getImpl() {
T ret = mImpl;
if (ret != null) {
return ret;
}
assert isInstalled();
try (Timer timer = new Timer()) {
ModuleDescriptor moduleDescriptor = getModuleDescriptor();
if (moduleDescriptor.getLoadNativeOnGetImpl()) {
// Load the module's native code and/or resources if they are present, and the
// Chrome native library itself has been loaded.
ensureNativeLoaded();
}
Object impl = instantiateReflectively(mImplClassName);
try {
ret = mInterfaceClass.cast(impl);
mImpl = ret;
} catch (ClassCastException e) {
ClassLoader interfaceClassLoader = mInterfaceClass.getClassLoader();
ClassLoader implClassLoader = impl.getClass().getClassLoader();
throw new RuntimeException(
"Failure casting "
+ mName
+ " module class, interface ClassLoader: "
+ interfaceClassLoader
+ " (parent "
+ interfaceClassLoader.getParent()
+ ")"
+ ", impl ClassLoader: "
+ implClassLoader
+ " (parent "
+ implClassLoader.getParent()
+ ")"
+ ", equal: "
+ interfaceClassLoader.equals(implClassLoader)
+ " (parents equal: "
+ interfaceClassLoader
.getParent()
.equals(implClassLoader.getParent())
+ ")",
e);
}
}
return ret;
}
/**
* Loads native libraries and/or resources if and only if this is not already done, assuming
* that the module is installed, and enableNativeLoad() has been called.
*/
public void ensureNativeLoaded() {
// Can only initialize native once per lifetime of Chrome.
if (mIsNativeLoaded) return;
assert LibraryLoader.getInstance().isInitialized();
ModuleDescriptor moduleDescriptor = getModuleDescriptor();
String[] libraries = moduleDescriptor.getLibraries();
String[] paks = moduleDescriptor.getPaks();
if (libraries.length > 0 || paks.length > 0) {
ModuleJni.get().loadNative(mName, libraries, paks);
}
mIsNativeLoaded = true;
}
/**
* Loads the {@link ModuleDescriptor} for a module.
*
* For bundles, uses reflection to load the descriptor from inside the
* module. For APKs, returns an empty descriptor since APKs won't have
* descriptors packaged into them.
*
* @return The module's {@link ModuleDescriptor}.
*/
private ModuleDescriptor getModuleDescriptor() {
ModuleDescriptor ret = mModuleDescriptor;
if (ret == null) {
if (BundleUtils.isBundle()) {
ret =
(ModuleDescriptor)
instantiateReflectively(
"org.chromium.components.module_installer.builder.ModuleDescriptor_"
+ mName);
} else {
ret =
new ModuleDescriptor() {
@Override
public String[] getLibraries() {
return new String[0];
}
@Override
public String[] getPaks() {
return new String[0];
}
@Override
public boolean getLoadNativeOnGetImpl() {
return false;
}
};
}
mModuleDescriptor = ret;
}
return ret;
}
/** Returns the Context associated with the module. */
public Context getContext() {
// Ensure mContext is initialized.
getImpl();
return mContext;
}
/**
* Instantiates an object via reflection.
*
* Ignores strict mode violations since accessing code in a module may cause its DEX file to be
* loaded and on some devices that can cause such a violation.
*
* @param className The object's class name.
* @return The object.
*/
private Object instantiateReflectively(String className) {
Context context = mContext;
if (context == null) {
context = ContextUtils.getApplicationContext();
String moduleName = mName;
if (BundleUtils.isIsolatedSplitInstalled(moduleName)) {
context = BundleUtils.createIsolatedSplitContext(context, moduleName);
}
}
try (StrictModeContext ignored = StrictModeContext.allowDiskReads()) {
Object ret = context.getClassLoader().loadClass(className).newInstance();
// Cache only if reflection succeeded since the module might not have been installed.
mContext = context;
return ret;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
@NativeMethods
interface Natives {
void loadNative(String name, String[] libraries, String[] paks);
}
}
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