/*
* Copyright 2011 Google Inc.
*
* 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 com.google.ipc.invalidation.external.client.contrib;
import com.google.android.gcm.GCMBaseIntentService;
import com.google.android.gcm.GCMBroadcastReceiver;
import com.google.android.gcm.GCMRegistrar;
import com.google.ipc.invalidation.external.client.SystemResources.Logger;
import com.google.ipc.invalidation.external.client.android.service.AndroidLogger;
import com.google.ipc.invalidation.ticl.android.c2dm.WakeLockManager;
import android.app.IntentService;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.ServiceInfo;
/**
* A Google Cloud Messaging listener class that rebroadcasts events as package-scoped
* broadcasts. This allows multiple components to share a single GCM connection.
* <p>
* This listener uses an API of broadcasted Intents that is modeled after that provided by
* {@link GCMBaseIntentService}. For each upcall (e.g., onMessage, on Registered, etc) specified
* by {@code GCMBaseIntentService}, there is an {@code EXTRA_OP_...} constant defined in
* {@link Intents}.
* <p>
* Note that this class does <b>NOT</b> handle registering with GCM; applications are still required
* to do that in the usual way (e.g., using the GCMRegistrar class from the GCM library).
* <p>
* In order to raise a {@code GCMBaseIntentService} event to listeners, this service will broadcast
* an Intent with the following properties:
* 1. The action of the Intent is {@link Intents#ACTION}
* 2. There is a boolean-valued extra in the Intent whose key is the {@code EXTRA_OP_...} key
* for that call and whose value is {@code true}. For any intent, exactly one {@code EXTRA_OP}
* extra will be set.
* 3. The Intent contains additional call-specific extras required to interpret it. (See note for
* onMessage, below).
* <p>
* Clients of this service <b>MUST NOT</b> assume that there is a one-to-one mapping between
* issued broadcasts and actual GCM intents. I.e., this service may issue broadcast intents
* spontaneously, and it may not issue an intent for every GCM event.
* <p>
* For the onMessage() call, the broadcast intent will contain key/value extras containing the
* message payload. These extras are guaranteed to be identical to those that would have been in
* the Intent provided to the onMessage call. However, clients <b>MUST NOT</b> assume that the
* Intent broadcast to communicate a GCM message is literally the same Intent generated by the GCM
* client library.
* <p>
* This class does not expose the {@code onError} call, since according to the GCM documentation
* there is nothing to do except log an error (which this class does).
*
*/
public class MultiplexingGcmListener extends GCMBaseIntentService {
/* This class is public so that it can be instantiated by the Android runtime. */
/** Constants used in broadcast Intents. */
public static final class Intents {
/** Prefix of the action and extras. */
private static final String PREFIX = "com.google.ipc.invalidation.gcmmplex.";
/** Action of all broadcast intents issued. */
public static final String ACTION = PREFIX + "EVENT";
/** Extra corresponding to an {@code onMessage} upcall. */
public static final String EXTRA_OP_MESSAGE = PREFIX + "MESSAGE";
/** Extra corresponding to an {@code onRegistered} upcall. */
public static final String EXTRA_OP_REGISTERED = PREFIX + "REGISTERED";
/** Extra corresponding to an {@code onUnregistered} upcall. */
public static final String EXTRA_OP_UNREGISTERED = PREFIX + "UNREGISTERED";
/** Extra corresponding to an {@code onDeletedMessages} upcall. */
public static final String EXTRA_OP_DELETED_MESSAGES = PREFIX + "DELETED_MSGS";
/**
* Extra set iff the operation is {@link #EXTRA_OP_REGISTERED} or
* {@link #EXTRA_OP_UNREGISTERED}; it is string-valued and holds the registration id.
*/
public static final String EXTRA_DATA_REG_ID = PREFIX + "REGID";
/**
* Extra set iff the operation is {@link #EXTRA_OP_DELETED_MESSAGES}; it is integer-valued
* and holds the number of deleted messages.
*/
public static final String EXTRA_DATA_NUM_DELETED_MSGS = PREFIX + "NUM_DELETED_MSGS";
}
/**
* {@link GCMBroadcastReceiver} that forwards GCM intents to the {@code MultiplexingGcmListener}
* class.
*/
public static class GCMReceiver extends GCMBroadcastReceiver {
/* This class is public so that it can be instantiated by the Android runtime. */
@Override
protected String getGCMIntentServiceClassName(Context context) {
return MultiplexingGcmListener.class.getName();
}
}
/**
* Convenience base class for client implementations. It provides base classes for a broadcast
* receiver and an intent service that work together to handle events from the
* {@code MultiplexingGcmListener} while holding a wake lock.
* <p>
* This class guarantees that the {@code onYYY} methods will be called holding a wakelock, and
* that the wakelock will be automatically released when the method returns.
* <p>
* The wakelock will also be automatically released
* {@link Receiver#WAKELOCK_TIMEOUT_MS} ms after the original Intent was received by the
* {@link Receiver} class, to guard against leaks. Applications requiring a longer-duration
* wakelock should acquire one on their own in the appropriate {@code onYYY} method.
*/
public static abstract class AbstractListener extends IntentService {
/** Prefix of all wakelocks acquired by the receiver and the intent service. */
private static final String WAKELOCK_PREFIX = "multiplexing-gcm-listener:";
/** Intent extra key used to hold wakelock names, for runtime checks. */
private static final String EXTRA_WAKELOCK_NAME =
"com.google.ipc.invalidation.gcmmplex.listener.WAKELOCK_NAME";
/** Logger for {@code AbstractListener}. */
private static final Logger logger = AndroidLogger.forTag("MplexGcmAbsListener");
/**
* A {@code BroadcastReceiver} to receive intents from the {@code MultiplexingGcmListener}
* service. It acquires a wakelock and forwards the intent to the service named by
* {@link #getServiceClass}, which must be a subclass of {@code AbstractListener}.
*/
public static abstract class Receiver extends BroadcastReceiver {
/** Timeout after which wakelocks will be automatically released. */
private static final int WAKELOCK_TIMEOUT_MS = 30 * 1000;
@Override
public final void onReceive(Context context, Intent intent) {
// This method is final to prevent subclasses from overriding it and introducing errors in
// the wakelock protocol.
Class<?> serviceClass = getServiceClass();
// If the service isn't an AbstractListener subclass, then it will not release the wakelock
// properly, causing bugs.
if (!AbstractListener.class.isAssignableFrom(serviceClass)) {
throw new RuntimeException(
"Service class is not a subclass of AbstractListener: " + serviceClass);
}
String wakelockKey = getWakelockKey(serviceClass);
intent.setClass(context, serviceClass);
// To avoid insidious bugs, tell the service which wakelock we acquired. The service will
// log a warning if the lock it releases is not this lock.
intent.putExtra(EXTRA_WAKELOCK_NAME, wakelockKey);
// Acquire the lock and start the service. The service is responsible for releasing the
// lock.
WakeLockManager.getInstance(context).acquire(wakelockKey, WAKELOCK_TIMEOUT_MS);
context.startService(intent);
}
/** Returns the class of the service that will handle intents. */
protected abstract Class<?> getServiceClass();
}
protected AbstractListener(String name) {
super(name);
// If the process dies during a call to onHandleIntent, redeliver the intent when the service
// restarts.
setIntentRedelivery(true);
}
@Override
public final void onHandleIntent(Intent intent) {
if (intent == null) {
return;
}
// This method is final to prevent subclasses from overriding it and introducing errors in
// the wakelock protocol.
try {
doHandleIntent(intent);
} finally {
// Release the wakelock acquired by the receiver. The receiver provides the name of the
// lock it acquired in the Intent so that we can sanity-check that we are releasing the
// right lock.
String receiverAcquiredWakelock = intent.getStringExtra(EXTRA_WAKELOCK_NAME);
String wakelockToRelease = getWakelockKey(getClass());
if (!wakelockToRelease.equals(receiverAcquiredWakelock)) {
logger.warning("Receiver acquired wakelock '%s' but releasing '%s'",
receiverAcquiredWakelock, wakelockToRelease);
}
WakeLockManager wakelockManager = WakeLockManager.getInstance(this);
wakelockManager.release(wakelockToRelease);
}
}
/** Handles {@code intent} while holding a wake lock. */
private void doHandleIntent(Intent intent) {
// Ensure this is an Intent we want to handle.
if (!MultiplexingGcmListener.Intents.ACTION.equals(intent.getAction())) {
logger.warning("Ignoring intent with unknown action: %s", intent);
return;
}
// Dispatch based on the extras.
if (intent.hasExtra(MultiplexingGcmListener.Intents.EXTRA_OP_MESSAGE)) {
onMessage(intent);
} else if (intent.hasExtra(MultiplexingGcmListener.Intents.EXTRA_OP_REGISTERED)) {
onRegistered(intent.getStringExtra(MultiplexingGcmListener.Intents.EXTRA_DATA_REG_ID));
} else if (intent.hasExtra(MultiplexingGcmListener.Intents.EXTRA_OP_UNREGISTERED)) {
onUnregistered(intent.getStringExtra(MultiplexingGcmListener.Intents.EXTRA_DATA_REG_ID));
} else if (intent.hasExtra(MultiplexingGcmListener.Intents.EXTRA_OP_DELETED_MESSAGES)) {
int numDeleted =
intent.getIntExtra(MultiplexingGcmListener.Intents.EXTRA_DATA_NUM_DELETED_MSGS, -1);
if (numDeleted == -1) {
logger.warning("Could not parse num-deleted field of GCM broadcast: %s", intent);
return;
}
onDeletedMessages(numDeleted);
} else {
logger.warning("Broadcast GCM intent with no known operation: %s", intent);
}
}
// These methods have the same specs as in {@code GCMBaseIntentService}.
protected abstract void onMessage(Intent intent);
protected abstract void onRegistered(String registrationId);
protected abstract void onUnregistered(String registrationId);
protected abstract void onDeletedMessages(int total);
/**
* Returns the name of the wakelock to acquire for the intent service implemented by
* {@code clazz}.
*/
private static String getWakelockKey(Class<?> clazz) {
return WAKELOCK_PREFIX + clazz.getName();
}
}
/**
* Name of the metadata element within the {@code service} element whose value is a
* comma-delimited list of GCM sender ids.
*/
private static final String GCM_SENDER_IDS_METADATA_KEY = "sender_ids";
/** Logger. */
private static final Logger logger = AndroidLogger.forTag("MplexGcmListener");
// All onYYY methods work by constructing an appropriate Intent and broadcasting it.
@Override
protected void onMessage(Context context, Intent intent) {
Intent newIntent = new Intent();
newIntent.putExtra(Intents.EXTRA_OP_MESSAGE, true);
// Copy the extra keys containing the message payload into the new Intent.
for (String extraKey : intent.getExtras().keySet()) {
newIntent.putExtra(extraKey, intent.getStringExtra(extraKey));
}
rebroadcast(newIntent);
}
@Override
protected void onRegistered(Context context, String registrationId) {
Intent intent = new Intent();
intent.putExtra(Intents.EXTRA_OP_REGISTERED, true);
intent.putExtra(Intents.EXTRA_DATA_REG_ID, registrationId);
rebroadcast(intent);
}
@Override
protected void onUnregistered(Context context, String registrationId) {
Intent intent = new Intent();
intent.putExtra(Intents.EXTRA_OP_UNREGISTERED, true);
intent.putExtra(Intents.EXTRA_DATA_REG_ID, registrationId);
rebroadcast(intent);
}
@Override
protected void onDeletedMessages(Context context, int total) {
Intent intent = new Intent();
intent.putExtra(Intents.EXTRA_OP_DELETED_MESSAGES, true);
intent.putExtra(Intents.EXTRA_DATA_NUM_DELETED_MSGS, total);
rebroadcast(intent);
}
@Override
protected void onError(Context context, String errorId) {
// This is called for unrecoverable errors, so just log a warning.
logger.warning("GCM error: %s", errorId);
}
@Override
protected String[] getSenderIds(Context context) {
return readSenderIdsFromManifestOrDie(this);
}
/**
* Broadcasts {@code intent} with the action set to {@link Intents#ACTION} and the package name
* set to the package name of this service.
*/
private void rebroadcast(Intent intent) {
intent.setAction(Intents.ACTION);
intent.setPackage(getPackageName());
sendBroadcast(intent);
}
/**
* Registers with GCM if not already registered. Also verifies that the device supports GCM
* and that the manifest is correctly configured. Returns the existing registration id, if one
* exists, or the empty string if one does not.
*
* @throws UnsupportedOperationException if the device does not have all GCM dependencies
* @throws IllegalStateException if the manifest is not correctly configured
*/
public static String initializeGcm(Context context) {
GCMRegistrar.checkDevice(context);
GCMRegistrar.checkManifest(context);
final String regId = GCMRegistrar.getRegistrationId(context);
if (regId.equals("")) {
GCMRegistrar.register(context, readSenderIdsFromManifestOrDie(context));
}
return regId;
}
/**
* Returns the GCM sender ids from {@link #GCM_SENDER_IDS_METADATA_KEY} or throws a
* {@code RuntimeException} if they are not defined.
*/
static String[] readSenderIdsFromManifestOrDie(Context context) {
try {
ServiceInfo serviceInfo = context.getPackageManager().getServiceInfo(
new ComponentName(context, MultiplexingGcmListener.class), PackageManager.GET_META_DATA);
if (serviceInfo.metaData == null) {
throw new RuntimeException("Service has no metadata");
}
String senderIds = serviceInfo.metaData.getString(GCM_SENDER_IDS_METADATA_KEY);
if (senderIds == null) {
throw new RuntimeException("Service does not have the sender-ids metadata");
}
return senderIds.split(",");
} catch (NameNotFoundException exception) {
throw new RuntimeException("Could not read service info from manifest", exception);
}
}
}