Set target to android 18

[fonbot.git] / lib / com / google / android / gcm / GCMRegistrar.java

/*
 * Copyright 2012 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.android.gcm;

import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Build;
import android.util.Log;

/**
 * Utilities for device registration.
 * <p>
 * <strong>Note:</strong> this class uses a private {@link SharedPreferences}
 * object to keep track of the registration token.
 */
public final class GCMRegistrar {

    /**
     * Default lifespan (7 days) of the {@link #isRegisteredOnServer(Context)}
     * flag until it is considered expired.
     */
    // NOTE: cannot use TimeUnit.DAYS because it's not available on API Level 8
    public static final long DEFAULT_ON_SERVER_LIFESPAN_MS =
            1000 * 3600 * 24 * 7;

    private static final String TAG = "GCMRegistrar";
    private static final String BACKOFF_MS = "backoff_ms";
    private static final String GSF_PACKAGE = "com.google.android.gsf";
    private static final String PREFERENCES = "com.google.android.gcm";
    private static final int DEFAULT_BACKOFF_MS = 3000;
    private static final String PROPERTY_REG_ID = "regId";
    private static final String PROPERTY_APP_VERSION = "appVersion";
    /**
     * {@link GCMBroadcastReceiver} instance used to handle the retry intent.
     *
     * <p>
     * This instance cannot be the same as the one defined in the manifest
     * because it needs a different permission.
     */
    private static GCMBroadcastReceiver sRetryReceiver;

    private static String sRetryReceiverClassName;

    /**
     * Checks if the device has the proper dependencies installed.
     * <p>
     * This method should be called when the application starts to verify that
     * the device supports GCM.
     *
     * @param context application context.
     * @throws UnsupportedOperationException if the device does not support GCM.
     */
    public static void checkDevice(final Context context) {
        final int version = Build.VERSION.SDK_INT;
        if (version < 8) {
            throw new UnsupportedOperationException("Device must be at least " +
                    "API Level 8 (instead of " + version + ")");
        }
        final PackageManager packageManager = context.getPackageManager();
        try {
            packageManager.getPackageInfo(GSF_PACKAGE, 0);
        } catch (NameNotFoundException e) {
            throw new UnsupportedOperationException(
                    "Device does not have package " + GSF_PACKAGE);
        }
    }

    /**
     * Initiate messaging registration for the current application.
     * <p>
     * The result will be returned as an
     * {@link GCMConstants#INTENT_FROM_GCM_REGISTRATION_CALLBACK} intent with
     * either a {@link GCMConstants#EXTRA_REGISTRATION_ID} or
     * {@link GCMConstants#EXTRA_ERROR}.
     *
     * @param context application context.
     * @param senderIds Google Project ID of the accounts authorized to send
     *    messages to this application.
     * @throws IllegalStateException if device does not have all GCM
     *             dependencies installed.
     */
    public static void register(Context context, String... senderIds) {
        GCMRegistrar.resetBackoff(context);
        internalRegister(context, senderIds);
    }

    static void internalRegister(Context context, String... senderIds) {
        String flatSenderIds = getFlatSenderIds(senderIds);
        Log.v(TAG, "Registering app "  + context.getPackageName() +
                " of senders " + flatSenderIds);
        Intent intent = new Intent(GCMConstants.INTENT_TO_GCM_REGISTRATION);
        intent.setPackage(GSF_PACKAGE);
        intent.putExtra(GCMConstants.EXTRA_APPLICATION_PENDING_INTENT,
                PendingIntent.getBroadcast(context, 0, new Intent(), 0));
        intent.putExtra(GCMConstants.EXTRA_SENDER, flatSenderIds);
        context.startService(intent);
    }

    static String getFlatSenderIds(String... senderIds) {
        if (senderIds == null || senderIds.length == 0) {
            throw new IllegalArgumentException("No senderIds");
        }
        StringBuilder builder = new StringBuilder(senderIds[0]);
        for (int i = 1; i < senderIds.length; i++) {
            builder.append(',').append(senderIds[i]);
        }
        return builder.toString();
    }

    /**
     * Clear internal resources.
     *
     * <p>
     * This method should be called by the main activity's {@code onDestroy()}
     * method.
     */
    public static synchronized void onDestroy(Context context) {
        if (sRetryReceiver != null) {
            Log.v(TAG, "Unregistering receiver");
            context.unregisterReceiver(sRetryReceiver);
            sRetryReceiver = null;
        }
    }

    static void internalUnregister(Context context) {
        Log.v(TAG, "Unregistering app "  + context.getPackageName());
        Intent intent = new Intent(GCMConstants.INTENT_TO_GCM_UNREGISTRATION);
        intent.setPackage(GSF_PACKAGE);
        intent.putExtra(GCMConstants.EXTRA_APPLICATION_PENDING_INTENT,
                PendingIntent.getBroadcast(context, 0, new Intent(), 0));
        context.startService(intent);
    }

    /**
     * Lazy initializes the {@link GCMBroadcastReceiver} instance.
     */
    static synchronized void setRetryBroadcastReceiver(Context context) {
        if (sRetryReceiver == null) {
            if (sRetryReceiverClassName == null) {
                // should never happen
                Log.e(TAG, "internal error: retry receiver class not set yet");
                sRetryReceiver = new GCMBroadcastReceiver();
            } else {
                Class<?> clazz;
                try {
                    clazz = Class.forName(sRetryReceiverClassName);
                    sRetryReceiver = (GCMBroadcastReceiver) clazz.newInstance();
                } catch (Exception e) {
                    Log.e(TAG, "Could not create instance of " +
                            sRetryReceiverClassName + ". Using " +
                            GCMBroadcastReceiver.class.getName() +
                            " directly.");
                    sRetryReceiver = new GCMBroadcastReceiver();
                }
            }
            String category = context.getPackageName();
            IntentFilter filter = new IntentFilter(
                    GCMConstants.INTENT_FROM_GCM_LIBRARY_RETRY);
            filter.addCategory(category);
            // must use a permission that is defined on manifest for sure
            String permission = category + ".permission.C2D_MESSAGE";
            Log.v(TAG, "Registering receiver");
            context.registerReceiver(sRetryReceiver, filter, permission, null);
        }
    }

    /**
     * Sets the name of the retry receiver class.
     */
    static void setRetryReceiverClassName(String className) {
        Log.v(TAG, "Setting the name of retry receiver class to " + className);
        sRetryReceiverClassName = className;
    }

    /**
     * Gets the current registration id for application on GCM service.
     * <p>
     * If result is empty, the registration has failed.
     *
     * @return registration id, or empty string if the registration is not
     *         complete.
     */
    public static String getRegistrationId(Context context) {
        final SharedPreferences prefs = getGCMPreferences(context);
        String registrationId = prefs.getString(PROPERTY_REG_ID, "");
        // check if app was updated; if so, it must clear registration id to
        // avoid a race condition if GCM sends a message
        int oldVersion = prefs.getInt(PROPERTY_APP_VERSION, Integer.MIN_VALUE);
        int newVersion = getAppVersion(context);
        if (oldVersion != Integer.MIN_VALUE && oldVersion != newVersion) {
            Log.v(TAG, "App version changed from " + oldVersion + " to " +
                    newVersion + "; resetting registration id");
            clearRegistrationId(context);
            registrationId = "";
        }
        return registrationId;
    }

    /**
     * Checks whether the application was successfully registered on GCM
     * service.
     */
    static boolean isRegistered(Context context) {
        return getRegistrationId(context).length() > 0;
    }

    /**
     * Clears the registration id in the persistence store.
     *
     * @param context application's context.
     * @return old registration id.
     */
    static String clearRegistrationId(Context context) {
        return setRegistrationId(context, "");
    }

    /**
     * Sets the registration id in the persistence store.
     *
     * @param context application's context.
     * @param regId registration id
     */
    static String setRegistrationId(Context context, String regId) {
        final SharedPreferences prefs = getGCMPreferences(context);
        String oldRegistrationId = prefs.getString(PROPERTY_REG_ID, "");
        int appVersion = getAppVersion(context);
        Log.v(TAG, "Saving regId on app version " + appVersion);
        Editor editor = prefs.edit();
        editor.putString(PROPERTY_REG_ID, regId);
        editor.putInt(PROPERTY_APP_VERSION, appVersion);
        editor.commit();
        return oldRegistrationId;
    }

    /**
     * Gets the application version.
     */
    private static int getAppVersion(Context context) {
        try {
            PackageInfo packageInfo = context.getPackageManager()
                    .getPackageInfo(context.getPackageName(), 0);
            return packageInfo.versionCode;
        } catch (NameNotFoundException e) {
            // should never happen
            throw new RuntimeException("Coult not get package name: " + e);
        }
    }

    /**
     * Resets the backoff counter.
     * <p>
     * This method should be called after a GCM call succeeds.
     *
     * @param context application's context.
     */
    static void resetBackoff(Context context) {
        Log.d(TAG, "resetting backoff for " + context.getPackageName());
        setBackoff(context, DEFAULT_BACKOFF_MS);
    }

    /**
     * Gets the current backoff counter.
     *
     * @param context application's context.
     * @return current backoff counter, in milliseconds.
     */
    static int getBackoff(Context context) {
        final SharedPreferences prefs = getGCMPreferences(context);
        return prefs.getInt(BACKOFF_MS, DEFAULT_BACKOFF_MS);
    }

    /**
     * Sets the backoff counter.
     * <p>
     * This method should be called after a GCM call fails, passing an
     * exponential value.
     *
     * @param context application's context.
     * @param backoff new backoff counter, in milliseconds.
     */
    static void setBackoff(Context context, int backoff) {
        final SharedPreferences prefs = getGCMPreferences(context);
        Editor editor = prefs.edit();
        editor.putInt(BACKOFF_MS, backoff);
        editor.commit();
    }

    private static SharedPreferences getGCMPreferences(Context context) {
        return context.getSharedPreferences(PREFERENCES, Context.MODE_PRIVATE);
    }

    private GCMRegistrar() {
        throw new UnsupportedOperationException();
    }
}