/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.car.app;
import static androidx.car.app.utils.LogTags.TAG;
import static androidx.car.app.utils.ThreadUtils.runOnMain;
import static java.util.Objects.requireNonNull;
import android.app.Service;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import androidx.annotation.CallSuper;
import androidx.annotation.MainThread;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.VisibleForTesting;
import androidx.car.app.CarContext.CarServiceType;
import androidx.car.app.navigation.NavigationManager;
import androidx.car.app.serialization.Bundleable;
import androidx.car.app.serialization.BundlerException;
import androidx.car.app.utils.RemoteUtils;
import androidx.car.app.utils.ThreadUtils;
import androidx.car.app.validation.HostValidator;
import androidx.car.app.versioning.CarAppApiLevels;
import androidx.lifecycle.Lifecycle;
import androidx.lifecycle.Lifecycle.Event;
import androidx.lifecycle.Lifecycle.State;
import androidx.lifecycle.LifecycleRegistry;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.security.InvalidParameterException;
/**
* The base class for implementing a car app that runs in the car.
*
* <h4>Service Declaration</h4>
*
* The app must extend the {@link CarAppService} to be bound by the car host. The service must also
* respond to {@link Intent} actions coming from the host, by adding an
* <code>intent-filter</code> to the service in the <code>AndroidManifest.xml</code> that handles
* the {@link #SERVICE_INTERFACE} action. The app must also declare what category of application
* it is (e.g. {@link #CATEGORY_NAVIGATION_APP}). For example:
*
* <pre>{@code
* <service
* android:name=".YourAppService"
* android:exported="true">
* <intent-filter>
* <action android:name="androidx.car.app.CarAppService" />
* <category android:name="androidx.car.app.category.NAVIGATION"/>
* </intent-filter>
* </service>
* }</pre>
*
* <p>For a list of all the supported categories see
* <a href="https://developer.android.com/training/cars/apps#supported-app-categories">Supported App Categories</a>.
*
* <h4>Accessing Location</h4>
*
* When the app is running in the car display, the system will not consider it as being in the
* foreground, and hence it will be considered in the background for the purpose of retrieving
* location as described <a
* href="https://developer.android.com/about/versions/10/privacy/changes#app-access-device
* -location">here</a>.
*
* <p>To reliably get location for your car app, we recommended that you use a <a
* href="https://developer.android.com/guide/components/services?#Types-of-services">foreground
* service</a>. If you have a service other than your {@link CarAppService} that accesses
* location, run the service and your `CarAppService` in the same process. Also note that
* accessing location may become unreliable when the phone is in the battery saver mode.
*/
public abstract class CarAppService extends Service {
/**
* The full qualified name of the {@link CarAppService} class.
*
* <p>This is the same name that must be used to declare the action of the intent filter for
* the app's {@link CarAppService} in the app's manifest.
*
* @see CarAppService
*/
public static final String SERVICE_INTERFACE = "androidx.car.app.CarAppService";
/**
* Used to declare that this app is a navigation app in the manifest.
*/
public static final String CATEGORY_NAVIGATION_APP = "androidx.car.app.category.NAVIGATION";
/**
* Used to declare that this app is a parking app in the manifest.
*/
public static final String CATEGORY_PARKING_APP = "androidx.car.app.category.PARKING";
/**
* Used to declare that this app is a charging app in the manifest.
*/
public static final String CATEGORY_CHARGING_APP = "androidx.car.app.category.CHARGING";
private static final String AUTO_DRIVE = "AUTO_DRIVE";
@Nullable
private AppInfo mAppInfo;
@Nullable
private Session mCurrentSession;
@Nullable
private HostValidator mHostValidator;
@Nullable
private HostInfo mHostInfo;
@Nullable
private HandshakeInfo mHandshakeInfo;
@Nullable
private CarAppBinder mBinder;
@Override
@CallSuper
public void onCreate() {
mBinder = new CarAppBinder(this);
}
@Override
@CallSuper
public void onDestroy() {
if (mBinder != null) {
mBinder.destroy();
mBinder = null;
}
}
/**
* Handles the host binding to this car app.
*
* <p>This method is final to ensure this car app's lifecycle is handled properly.
*
* <p>Use {@link #onCreateSession()} and {@link Session#onNewIntent} instead to handle incoming
* {@link Intent}s.
*/
@Override
@CallSuper
@NonNull
public final IBinder onBind(@NonNull Intent intent) {
return requireNonNull(mBinder);
}
/**
* Handles the host unbinding from this car app.
*
* <p>This method is final to ensure this car app's lifecycle is handled properly.
*/
@Override
public final boolean onUnbind(@NonNull Intent intent) {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onUnbind intent: " + intent);
}
runOnMain(() -> {
if (mCurrentSession != null) {
// Destroy the session
// The session's lifecycle is observed by some of the manager and they will
// perform cleanup on destroy. For example, the ScreenManager can destroy all
// Screens it holds.
LifecycleRegistry lifecycleRegistry = getLifecycleIfValid();
if (lifecycleRegistry == null) {
Log.e(TAG, "Null Session when unbinding");
} else {
lifecycleRegistry.handleLifecycleEvent(Event.ON_DESTROY);
}
}
mCurrentSession = null;
});
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onUnbind completed");
}
// Return true to request an onRebind call. This means that the process will cache this
// instance of the Service to return on future bind calls.
return true;
}
/**
* Returns the {@link HostValidator} this service will use to accept or reject host connections.
*
* <p>By default, the provided {@link HostValidator.Builder} would produce a validator that
* only accepts connections from hosts holding
* {@link HostValidator#TEMPLATE_RENDERER_PERMISSION} permission.
*
* <p>Application developers are expected to also allow connections from known hosts which
* don't hold the aforementioned permission (for example, Android Auto and Android
* Automotive OS hosts below API level 31), by allow-listing the signatures of those hosts.
*
* <p>Refer to {@code androidx.car.app.R.array.hosts_allowlist_sample} to obtain a
* list of package names and signatures that should be allow-listed by default.
*
* <p>It is also advised to allow connections from unknown hosts in debug builds to facilitate
* debugging and testing.
*
* <p>Below is an example of this method implementation:
*
* <pre>
* @Override
* @NonNull
* public HostValidator createHostValidator() {
* if ((getApplicationInfo().flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0) {
* return HostValidator.ALLOW_ALL_HOSTS_VALIDATOR;
* } else {
* return new HostValidator.Builder(context)
* .addAllowedHosts(androidx.car.app.R.array.hosts_allowlist_sample)
* .build();
* }
* }
* </pre>
*/
@NonNull
public abstract HostValidator createHostValidator();
/**
* Creates a new {@link Session} for the application.
*
* <p>This method is invoked the first time the app is started, or if the previous
* {@link Session} instance has been destroyed and the system has not yet destroyed
* this service.
*
* <p>Once the method returns, {@link Session#onCreateScreen(Intent)} will be called on the
* {@link Session} returned.
*
* <p>Called by the system, do not call this method directly.
*
* @see CarContext#startCarApp(Intent)
*/
@NonNull
public abstract Session onCreateSession();
@Override
@CallSuper
public final void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer,
@Nullable String[] args) {
super.dump(fd, writer, args);
for (String arg : args) {
if (AUTO_DRIVE.equals(arg)) {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "Executing onAutoDriveEnabled");
}
runOnMain(() -> {
if (mCurrentSession != null) {
mCurrentSession.getCarContext().getCarService(
NavigationManager.class).onAutoDriveEnabled();
}
});
}
}
}
/**
* Returns information about the host attached to this service.
*
* @see HostInfo
*/
@Nullable
public final HostInfo getHostInfo() {
return mHostInfo;
}
void setHostInfo(@Nullable HostInfo hostInfo) {
mHostInfo = hostInfo;
}
/**
* Returns the current {@link Session} for this service.
*/
@Nullable
public final Session getCurrentSession() {
return mCurrentSession;
}
// Strictly to avoid synthetic accessor.
void setCurrentSession(@Nullable Session session) {
mCurrentSession = session;
}
// Strictly to avoid synthetic accessor.
@NonNull
AppInfo getAppInfo() {
if (mAppInfo == null) {
// Lazy-initialized as the package manager is not available if this is created inlined.
mAppInfo = AppInfo.create(this);
}
return mAppInfo;
}
/**
* Used by tests to verify the different behaviors when the app has different api level than
* the host.
*/
@VisibleForTesting
void setAppInfo(@Nullable AppInfo appInfo) {
mAppInfo = appInfo;
}
@NonNull
HostValidator getHostValidator() {
if (mHostValidator == null) {
mHostValidator = createHostValidator();
}
return mHostValidator;
}
/**
* Used by tests to verify the different behaviors when the app has different api level than
* the host.
*/
@VisibleForTesting
void setHandshakeInfo(@NonNull HandshakeInfo handshakeInfo) {
int apiLevel = handshakeInfo.getHostCarAppApiLevel();
if (!CarAppApiLevels.isValid(apiLevel)) {
throw new IllegalArgumentException("Invalid Car App API level received: " + apiLevel);
}
mHandshakeInfo = handshakeInfo;
}
// Strictly to avoid synthetic accessor.
@Nullable
HandshakeInfo getHandshakeInfo() {
return mHandshakeInfo;
}
@Nullable
LifecycleRegistry getLifecycleIfValid() {
Session session = getCurrentSession();
return session == null ? null : (LifecycleRegistry) session.getLifecycleInternal();
}
@NonNull
LifecycleRegistry getLifecycle() {
return requireNonNull(getLifecycleIfValid());
}
private static final class CarAppBinder extends ICarApp.Stub {
@Nullable private CarAppService mService;
CarAppBinder(@NonNull CarAppService service) {
mService = service;
}
/**
* Explicitly mark the binder to be destroyed and remove the reference to the
* {@link CarAppService}, and any subsequent call from the host after this would be
* considered invalid and throws an exception.
*
* <p>This is needed because the binder object can outlive the service and will not be
* garbage collected until the car host cleans up its side of the binder reference,
* causing a leak. See https://github.com/square/leakcanary/issues/1906 for more context
* related to this issue.
*/
void destroy() {
mService = null;
}
// incompatible argument for parameter context of attachBaseContext.
// call to onCreateScreen(android.content.Intent) not allowed on the given receiver.
@SuppressWarnings({
"nullness:argument.type.incompatible",
"nullness:method.invocation.invalid"
})
@Override
public void onAppCreate(
ICarHost carHost,
Intent intent,
Configuration configuration,
IOnDoneCallback callback) {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onAppCreate intent: " + intent);
}
RemoteUtils.dispatchCallFromHost(callback, "onAppCreate", () -> {
CarAppService service = requireNonNull(mService);
Session session = service.getCurrentSession();
if (session == null
|| service.getLifecycle().getCurrentState() == State.DESTROYED) {
session = service.onCreateSession();
service.setCurrentSession(session);
}
session.configure(service,
requireNonNull(service.getHandshakeInfo()),
requireNonNull(service.getHostInfo()),
carHost, configuration);
// Whenever the host unbinds, the screens in the stack are destroyed. If
// there is another bind, before the OS has destroyed this Service, then
// the stack will be empty, and we need to treat it as a new instance.
LifecycleRegistry registry = service.getLifecycle();
Lifecycle.State state = registry.getCurrentState();
int screenStackSize = session.getCarContext().getCarService(
ScreenManager.class).getScreenStack().size();
if (!state.isAtLeast(State.CREATED) || screenStackSize < 1) {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onAppCreate the app was not yet created or the "
+ "screen stack was empty state: "
+ registry.getCurrentState()
+ ", stack size: " + screenStackSize);
}
registry.handleLifecycleEvent(Event.ON_CREATE);
session.getCarContext().getCarService(ScreenManager.class).push(
session.onCreateScreen(intent));
} else {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onAppCreate the app was already created");
}
onNewIntentInternal(session, intent);
}
return null;
});
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onAppCreate completed");
}
}
@Override
public void onAppStart(IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(), callback,
"onAppStart", () -> {
service.getLifecycle().handleLifecycleEvent(Event.ON_START);
return null;
});
}
@Override
public void onAppResume(IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(), callback,
"onAppResume", () -> {
service.getLifecycle()
.handleLifecycleEvent(Event.ON_RESUME);
return null;
});
}
@Override
public void onAppPause(IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(), callback, "onAppPause",
() -> {
service.getLifecycle().handleLifecycleEvent(Event.ON_PAUSE);
return null;
});
}
@Override
public void onAppStop(IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(), callback, "onAppStop",
() -> {
service.getLifecycle().handleLifecycleEvent(Event.ON_STOP);
return null;
});
}
@Override
public void onNewIntent(Intent intent, IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(),
callback,
"onNewIntent",
() -> {
onNewIntentInternal(requireNonNull(service.getCurrentSession()), intent);
return null;
});
}
@Override
public void onConfigurationChanged(Configuration configuration,
IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
RemoteUtils.dispatchCallFromHost(
service.getLifecycleIfValid(),
callback,
"onConfigurationChanged",
() -> {
onConfigurationChangedInternal(requireNonNull(service.getCurrentSession()),
configuration);
return null;
});
}
@Override
public void getManager(@CarServiceType @NonNull String type,
IOnDoneCallback callback) {
ThreadUtils.runOnMain(() -> {
CarAppService service = requireNonNull(mService);
Session session = requireNonNull(service.getCurrentSession());
switch (type) {
case CarContext.APP_SERVICE:
RemoteUtils.sendSuccessResponseToHost(
callback,
"getManager",
session.getCarContext().getCarService(
AppManager.class).getIInterface());
return;
case CarContext.NAVIGATION_SERVICE:
RemoteUtils.sendSuccessResponseToHost(
callback,
"getManager",
session.getCarContext().getCarService(
NavigationManager.class).getIInterface());
return;
default:
Log.e(TAG, type + "%s is not a valid manager");
RemoteUtils.sendFailureResponseToHost(callback, "getManager",
new InvalidParameterException(
type + " is not a valid manager type"));
}
});
}
@Override
public void getAppInfo(IOnDoneCallback callback) {
try {
CarAppService service = requireNonNull(mService);
RemoteUtils.sendSuccessResponseToHost(
callback, "getAppInfo", service.getAppInfo());
} catch (IllegalArgumentException e) {
// getAppInfo() could fail with the specified API version is invalid.
RemoteUtils.sendFailureResponseToHost(callback, "getAppInfo", e);
}
}
@Override
public void onHandshakeCompleted(Bundleable handshakeInfo,
IOnDoneCallback callback) {
CarAppService service = requireNonNull(mService);
try {
HandshakeInfo deserializedHandshakeInfo =
(HandshakeInfo) handshakeInfo.get();
String packageName = deserializedHandshakeInfo.getHostPackageName();
int uid = Binder.getCallingUid();
HostInfo hostInfo = new HostInfo(packageName, uid);
if (!service.getHostValidator().isValidHost(hostInfo)) {
RemoteUtils.sendFailureResponseToHost(callback, "onHandshakeCompleted",
new IllegalArgumentException("Unknown host '"
+ packageName + "', uid:" + uid));
return;
}
int appMinApiLevel = service.getAppInfo().getMinCarAppApiLevel();
int hostApiLevel = deserializedHandshakeInfo.getHostCarAppApiLevel();
if (appMinApiLevel > hostApiLevel) {
RemoteUtils.sendFailureResponseToHost(callback, "onHandshakeCompleted",
new IllegalArgumentException(
"Host API level (" + hostApiLevel + ") is "
+ "less than the app's min API level ("
+ appMinApiLevel + ")"));
return;
}
service.setHostInfo(hostInfo);
service.setHandshakeInfo(deserializedHandshakeInfo);
RemoteUtils.sendSuccessResponseToHost(callback, "onHandshakeCompleted",
null);
} catch (BundlerException | IllegalArgumentException e) {
service.setHostInfo(null);
RemoteUtils.sendFailureResponseToHost(callback, "onHandshakeCompleted", e);
}
}
// call to onNewIntent(android.content.Intent) not allowed on the given receiver.
@SuppressWarnings("nullness:method.invocation.invalid")
@MainThread
private void onNewIntentInternal(Session session, Intent intent) {
ThreadUtils.checkMainThread();
session.onNewIntent(intent);
}
// call to onCarConfigurationChanged(android.content.res.Configuration) not
// allowed on the given receiver.
@SuppressWarnings("nullness:method.invocation.invalid")
@MainThread
private void onConfigurationChangedInternal(Session session,
Configuration configuration) {
ThreadUtils.checkMainThread();
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(TAG, "onCarConfigurationChanged configuration: " + configuration);
}
session.onCarConfigurationChangedInternal(configuration);
}
}
}