/**
 * Interface to global information about an application environment.  This is
 * an abstract class whose implementation is provided by
 * the Android system.  It
 * allows access to application-specific resources and classes, as well as
 * up-calls for application-level operations such as launching activities,
 * broadcasting and receiving intents, etc.
 */

/**
 * Interface to global information about an application environment.  This is
 * an abstract class whose implementation is provided by
 * the Android system.  It
 * allows access to application-specific resources and classes, as well as
 * up-calls for application-level operations such as launching activities,
 * broadcasting and receiving intents, etc.
 */
public abstract class Context {

    ……

    /**
     * Returns an AssetManager instance for the application‘s package.
     * <p>
     * <strong>Note:</strong> Implementations of this method should return
     * an AssetManager instance that is consistent with the Resources instance
     * returned by {@link #getResources()}. For example, they should share the
     * same {@link Configuration} object.
     *
     * @return an AssetManager instance for the application‘s package
     * @see #getResources()
     */
    public abstract AssetManager getAssets();

    /**
     * Returns a Resources instance for the application‘s package.
     * <p>
     * <strong>Note:</strong> Implementations of this method should return
     * a Resources instance that is consistent with the AssetManager instance
     * returned by {@link #getAssets()}. For example, they should share the
     * same {@link Configuration} object.
     *
     * @return a Resources instance for the application‘s package
     * @see #getAssets()
     */
    public abstract Resources getResources();

    /** Return PackageManager instance to find global package information. */
    public abstract PackageManager getPackageManager();

    /**
     * Return the context of the single, global Application object of the
     * current process.  This generally should only be used if you need a
     * Context whose lifecycle is separate from the current context, that is
     * tied to the lifetime of the process rather than the current component.
     *
     * <p>Consider for example how this interacts with
     * {@link #registerReceiver(BroadcastReceiver, IntentFilter)}:
     * <ul>
     * <li> <p>If used from an Activity context, the receiver is being registered
     * within that activity.  This means that you are expected to unregister
     * before the activity is done being destroyed; in fact if you do not do
     * so, the framework will clean up your leaked registration as it removes
     * the activity and log an error.  Thus, if you use the Activity context
     * to register a receiver that is static (global to the process, not
     * associated with an Activity instance) then that registration will be
     * removed on you at whatever point the activity you used is destroyed.
     * <li> <p>If used from the Context returned here, the receiver is being
     * registered with the global state associated with your application.  Thus
     * it will never be unregistered for you.  This is necessary if the receiver
     * is associated with static data, not a particular component.  However
     * using the ApplicationContext elsewhere can easily lead to serious leaks
     * if you forget to unregister, unbind, etc.
     * </ul>
     */
    public abstract Context getApplicationContext();

    /** Return the name of this application‘s package. */
    public abstract String getPackageName();

    ……
    
}

/**
 * Common implementation of Context API, which provides the base
 * context object for Activity and other application components.
 */
class ContextImpl extends Context {
    private final static String TAG = "ContextImpl";
    private final static boolean DEBUG = false;

    private static final String XATTR_INODE_CACHE = "user.inode_cache";
    private static final String XATTR_INODE_CODE_CACHE = "user.inode_code_cache";

    /**
     * Map from package name, to preference name, to cached preferences.
     */
    @GuardedBy("ContextImpl.class")
    @UnsupportedAppUsage
    private static ArrayMap<String, ArrayMap<File, SharedPreferencesImpl>> sSharedPrefsCache;

    /**
     * Map from preference name to generated path.
     */
    @GuardedBy("ContextImpl.class")
    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
    private ArrayMap<String, File> mSharedPrefsPaths;

    @UnsupportedAppUsage
    final @NonNull ActivityThread mMainThread;
    @UnsupportedAppUsage
    final @NonNull LoadedApk mPackageInfo;
    @UnsupportedAppUsage
    private @Nullable ClassLoader mClassLoader;

    private final @Nullable IBinder mToken;

    private final @NonNull UserHandle mUser;

    @UnsupportedAppUsage
    private final ApplicationContentResolver mContentResolver;

    @UnsupportedAppUsage
    private final String mBasePackageName;
    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
    private final String mOpPackageName;

    ……
    
}

/**
 * Proxying implementation of Context that simply delegates all of its calls to
 * another Context.  Can be subclassed to modify behavior without changing
 * the original Context.
 */
public class ContextWrapper extends Context {
    @UnsupportedAppUsage
    Context mBase;

    public ContextWrapper(Context base) {
        mBase = base;
    }

    /**
     * Set the base context for this ContextWrapper.  All calls will then be
     * delegated to the base context.  Throws
     * IllegalStateException if a base context has already been set.
     *
     * @param base The new base context for this wrapper.
     */
    protected void attachBaseContext(Context base) {
        if (mBase != null) {
            throw new IllegalStateException("Base context already set");
        }
        mBase = base;
    }

    /**
     * @return the base context as set by the constructor or setBaseContext
     */
    public Context getBaseContext() {
        return mBase;
    }

    @Override
    public AssetManager getAssets() {
        return mBase.getAssets();
    }

    @Override
    public Resources getResources() {
        return mBase.getResources();
    }

    @Override
    public PackageManager getPackageManager() {
        return mBase.getPackageManager();
    }

    @Override
    public ContentResolver getContentResolver() {
        return mBase.getContentResolver();
    }

    @Override
    public Looper getMainLooper() {
        return mBase.getMainLooper();
    }

    @Override
    public Executor getMainExecutor() {
        return mBase.getMainExecutor();
    }

    @Override
    public Context getApplicationContext() {
        return mBase.getApplicationContext();
    }

    @Override
    public void setTheme(int resid) {
        mBase.setTheme(resid);
    }

    /** @hide */
    @Override
    @UnsupportedAppUsage
    public int getThemeResId() {
        return mBase.getThemeResId();
    }

    @Override
    public Resources.Theme getTheme() {
        return mBase.getTheme();
    }

    @Override
    public ClassLoader getClassLoader() {
        return mBase.getClassLoader();
    }

    @Override
    public String getPackageName() {
        return mBase.getPackageName();
    }

    ……

}

/**
 * Base class for maintaining global application state. You can provide your own
 * implementation by creating a subclass and specifying the fully-qualified name
 * of this subclass as the <code>"android:name"</code> attribute in your
 * AndroidManifest.xml‘s <code>&lt;application&gt;</code> tag. The Application
 * class, or your subclass of the Application class, is instantiated before any
 * other class when the process for your application/package is created.
 *
 * <p class="note"><strong>Note: </strong>There is normally no need to subclass
 * Application.  In most situations, static singletons can provide the same
 * functionality in a more modular way.  If your singleton needs a global
 * context (for example to register broadcast receivers), include
 * {@link android.content.Context#getApplicationContext() Context.getApplicationContext()}
 * as a {@link android.content.Context} argument when invoking your singleton‘s
 * <code>getInstance()</code> method.
 * </p>
 */
public class Application extends ContextWrapper implements ComponentCallbacks2 {
    private static final String TAG = "Application";
    @UnsupportedAppUsage
    private ArrayList<ComponentCallbacks> mComponentCallbacks =
            new ArrayList<ComponentCallbacks>();
    @UnsupportedAppUsage
    private ArrayList<ActivityLifecycleCallbacks> mActivityLifecycleCallbacks =
            new ArrayList<ActivityLifecycleCallbacks>();
    @UnsupportedAppUsage
    private ArrayList<OnProvideAssistDataListener> mAssistCallbacks = null;

    /** @hide */
    @UnsupportedAppUsage
    public LoadedApk mLoadedApk;

……

}

@UnsupportedAppUsage
private void handleBindApplication(AppBindData data) {
    ……

    // If the app is being launched for full backup or restore, bring it up in
    // a restricted environment with the base application class.
    app = data.info.makeApplication(data.restrictedBackupMode, null);

    // Propagate autofill compat state
    app.setAutofillOptions(data.autofillOptions);

    // Propagate Content Capture options
    app.setContentCaptureOptions(data.contentCaptureOptions);

    mInitialApplication = app;

    ……

}

@UnsupportedAppUsage
public Application makeApplication(boolean forceDefaultAppClass, Instrumentation instrumentation) {
    if (mApplication != null) {
        return mApplication;
    }

    ……

    ContextImpl appContext = ContextImpl.createAppContext(mActivityThread, this);
    // The network security config needs to be aware of multiple
    // applications in the same process to handle discrepancies
    NetworkSecurityConfigProvider.handleNewApplication(appContext);
    app = mActivityThread.mInstrumentation.newApplication(cl, appClass, appContext);

    ……
}

/**
 * Perform instantiation of the process‘s {@link Application} object.  The
 * default implementation provides the normal system behavior.
 * 
 * @param cl The ClassLoader with which to instantiate the object.
 * @param className The name of the class implementing the Application
 *                  object.
 * @param context The context to initialize the application with
 * 
 * @return The newly instantiated Application object.
 */
public Application newApplication(ClassLoader cl, String className, Context context)
        throws InstantiationException, IllegalAccessException, 
        ClassNotFoundException {
    Application app = getFactory(context.getPackageName())
            .instantiateApplication(cl, className);
    app.attach(context);
    return app;
}

public class Application extends ContextWrapper implements ComponentCallbacks2 {

    ……

    @UnsupportedAppUsage
    /* package */ final void attach(Context context) {
        attachBaseContext(context);
        mLoadedApk = ContextImpl.getImpl(context).mPackageInfo;
    }

    ……

}

/**
 * Proxying implementation of Context that simply delegates all of its calls to
 * another Context.  Can be subclassed to modify behavior without changing
 * the original Context.
 */
public class ContextWrapper extends Context {
    @UnsupportedAppUsage
    Context mBase;

    public ContextWrapper(Context base) {
        mBase = base;
    }

    /**
     * Set the base context for this ContextWrapper.  All calls will then be
     * delegated to the base context.  Throws
     * IllegalStateException if a base context has already been set.
     *
     * @param base The new base context for this wrapper.
     */
    protected void attachBaseContext(Context base) {
        if (mBase != null) {
            throw new IllegalStateException("Base context already set");
        }
        mBase = base;
    }

    @Override
    public Context getApplicationContext() {
        return mBase.getApplicationContext();
    }

    ……

}

public class Activity extends ContextThemeWrapper
        implements LayoutInflater.Factory2,
        Window.Callback, KeyEvent.Callback,
        OnCreateContextMenuListener, ComponentCallbacks2,
        Window.OnWindowDismissedCallback,
        AutofillManager.AutofillClient, ContentCaptureManager.ContentCaptureClient {
       …… 
}

/**  Core implementation of activity launch. */
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {

    ……

    ContextImpl appContext = createBaseContextForActivity(r);
    Activity activity = null;
    try {
        java.lang.ClassLoader cl = appContext.getClassLoader();
        activity = mInstrumentation.newActivity(cl, component.getClassName(), r.intent);
        StrictMode.incrementExpectedActivityCount(activity.getClass());
        r.intent.setExtrasClassLoader(cl);
        r.intent.prepareToEnterProcess();
        if (r.state != null) {
            r.state.setClassLoader(cl);
        }
    } catch (Exception e) {
        if (!mInstrumentation.onException(activity, e)) {
            throw new RuntimeException(
                "Unable to instantiate activity " + component
                + ": " + e.toString(), e);
        }
    }

    ……

    activity.attach(appContext, this, getInstrumentation(), r.token,
                        r.ident, app, r.intent, r.activityInfo, title, r.parent,
                        r.embeddedID, r.lastNonConfigurationInstances, config,
                        r.referrer, r.voiceInteractor, window, r.configCallback,
                        r.assistToken);
    
    ……

    return activity;
}

/**
 * Perform instantiation of the process‘s {@link Activity} object.  The
 * default implementation provides the normal system behavior.
 * 
 * @param cl The ClassLoader with which to instantiate the object.
 * @param className The name of the class implementing the Activity
 *                  object.
 * @param intent The Intent object that specified the activity class being
 *               instantiated.
 * 
 * @return The newly instantiated Activity object.
 */
public Activity newActivity(ClassLoader cl, String className,
        Intent intent)
        throws InstantiationException, IllegalAccessException,
        ClassNotFoundException {
    String pkg = intent != null && intent.getComponent() != null
            ? intent.getComponent().getPackageName() : null;
    return getFactory(pkg).instantiateActivity(cl, className, intent);
}

/**  Core implementation of activity launch. */
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {

    ……

    activity.attach(appContext, this, getInstrumentation(), r.token,
                        r.ident, app, r.intent, r.activityInfo, title, r.parent,
                        r.embeddedID, r.lastNonConfigurationInstances, config,
                        r.referrer, r.voiceInteractor, window, r.configCallback,
                        r.assistToken);
    
    ……

    return activity;
}

@UnsupportedAppUsage
final void attach(Context context, ActivityThread aThread,
        Instrumentation instr, IBinder token, int ident,
        Application application, Intent intent, ActivityInfo info,
        CharSequence title, Activity parent, String id,
        NonConfigurationInstances lastNonConfigurationInstances,
        Configuration config, String referrer, IVoiceInteractor voiceInteractor,
        Window window, ActivityConfigCallback activityConfigCallback, IBinder assistToken) {

    attachBaseContext(context);

    ……
    
}

/**
    * Set the base context for this ContextWrapper.  All calls will then be
    * delegated to the base context.  Throws
    * IllegalStateException if a base context has already been set.
    *
    * @param base The new base context for this wrapper.
    */
protected void attachBaseContext(Context base) {
    if (mBase != null) {
        throw new IllegalStateException("Base context already set");
    }
    mBase = base;
}

public abstract class Service extends ContextWrapper implements ComponentCallbacks2,
        ContentCaptureManager.ContentCaptureClient {
    ……
}

@UnsupportedAppUsage
private void handleCreateService(CreateServiceData data) {
    // If we are getting ready to gc after going to the background, well
    // we are back active so skip it.
    unscheduleGcIdler();

    LoadedApk packageInfo = getPackageInfoNoCheck(
            data.info.applicationInfo, data.compatInfo);
    Service service = null;
    try {
        if (localLOGV) Slog.v(TAG, "Creating service " + data.info.name);

        ContextImpl context = ContextImpl.createAppContext(this, packageInfo);
        Application app = packageInfo.makeApplication(false, mInstrumentation);
        java.lang.ClassLoader cl = packageInfo.getClassLoader();
        service = packageInfo.getAppFactory()
                .instantiateService(cl, data.info.name, data.intent);
        // Service resources must be initialized with the same loaders as the application
        // context.
        context.getResources().addLoaders(
                app.getResources().getLoaders().toArray(new ResourcesLoader[0]));

        context.setOuterContext(service);
        service.attach(context, this, data.info.name, data.token, app,
                ActivityManager.getService());
        service.onCreate();
        mServices.put(data.token, service);
        try {
            ActivityManager.getService().serviceDoneExecuting(
                    data.token, SERVICE_DONE_EXECUTING_ANON, 0, 0);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    } catch (Exception e) {
        if (!mInstrumentation.onException(service, e)) {
            throw new RuntimeException(
                "Unable to create service " + data.info.name
                + ": " + e.toString(), e);
        }
    }
}

@UnsupportedAppUsage
public final void attach(
        Context context,
        ActivityThread thread, String className, IBinder token,
        Application application, Object activityManager) {
    attachBaseContext(context);
    mThread = thread;           // NOTE:  unused - remove?
    mClassName = className;
    mToken = token;
    mApplication = application;
    mActivityManager = (IActivityManager)activityManager;
    mStartCompatibility = getApplicationInfo().targetSdkVersion
            < Build.VERSION_CODES.ECLAIR;

    setContentCaptureOptions(application.getContentCaptureOptions());
}

/**
    * Set the base context for this ContextWrapper.  All calls will then be
    * delegated to the base context.  Throws
    * IllegalStateException if a base context has already been set.
    *
    * @param base The new base context for this wrapper.
    */
protected void attachBaseContext(Context base) {
    if (mBase != null) {
        throw new IllegalStateException("Base context already set");
    }
    mBase = base;
}