/*
* Copyright (C) 2013 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 com.android.systemui.statusbar;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.RemoteException;
import android.os.UserHandle;
import android.provider.Settings;
import android.util.Log;
import java.util.Arrays;
/**
* Manages a persistent connection to a service component defined in a secure setting.
*
* <p>If a valid service component is specified in the secure setting, starts it up and keeps it
* running; handling setting changes, package updates, component disabling, and unexpected
* process termination.
*
* <p>Clients can listen for important events using the supplied {@link Callbacks}.
*/
public class ServiceMonitor {
private static final int RECHECK_DELAY = 2000;
private static final int WAIT_FOR_STOP = 500;
public interface Callbacks {
/** The service does not exist or failed to bind */
void onNoService();
/** The service is about to start, this is a chance to perform cleanup and
* delay the start if necessary */
long onServiceStartAttempt();
}
// internal handler + messages used to serialize access to internal state
public static final int MSG_START_SERVICE = 1;
public static final int MSG_CONTINUE_START_SERVICE = 2;
public static final int MSG_STOP_SERVICE = 3;
public static final int MSG_PACKAGE_INTENT = 4;
public static final int MSG_CHECK_BOUND = 5;
public static final int MSG_SERVICE_DISCONNECTED = 6;
private final Handler mHandler = new Handler() {
public void handleMessage(Message msg) {
switch(msg.what) {
case MSG_START_SERVICE:
startService();
break;
case MSG_CONTINUE_START_SERVICE:
continueStartService();
break;
case MSG_STOP_SERVICE:
stopService();
break;
case MSG_PACKAGE_INTENT:
packageIntent((Intent)msg.obj);
break;
case MSG_CHECK_BOUND:
checkBound();
break;
case MSG_SERVICE_DISCONNECTED:
serviceDisconnected((ComponentName)msg.obj);
break;
}
}
};
private final ContentObserver mSettingObserver = new ContentObserver(mHandler) {
public void onChange(boolean selfChange) {
onChange(selfChange, null);
}
public void onChange(boolean selfChange, Uri uri) {
if (mDebug) Log.d(mTag, "onChange selfChange=" + selfChange + " uri=" + uri);
ComponentName cn = getComponentNameFromSetting();
if (cn == null && mServiceName == null || cn != null && cn.equals(mServiceName)) {
if (mDebug) Log.d(mTag, "skipping no-op restart");
return;
}
if (mBound) {
mHandler.sendEmptyMessage(MSG_STOP_SERVICE);
}
mHandler.sendEmptyMessageDelayed(MSG_START_SERVICE, WAIT_FOR_STOP);
}
};
private final class SC implements ServiceConnection, IBinder.DeathRecipient {
private ComponentName mName;
private IBinder mService;
public void onServiceConnected(ComponentName name, IBinder service) {
if (mDebug) Log.d(mTag, "onServiceConnected name=" + name + " service=" + service);
mName = name;
mService = service;
try {
service.linkToDeath(this, 0);
} catch (RemoteException e) {
Log.w(mTag, "Error linking to death", e);
}
}
public void onServiceDisconnected(ComponentName name) {
if (mDebug) Log.d(mTag, "onServiceDisconnected name=" + name);
boolean unlinked = mService.unlinkToDeath(this, 0);
if (mDebug) Log.d(mTag, " unlinked=" + unlinked);
mHandler.sendMessage(mHandler.obtainMessage(MSG_SERVICE_DISCONNECTED, mName));
}
public void binderDied() {
if (mDebug) Log.d(mTag, "binderDied");
mHandler.sendMessage(mHandler.obtainMessage(MSG_SERVICE_DISCONNECTED, mName));
}
}
private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String pkg = intent.getData().getSchemeSpecificPart();
if (mServiceName != null && mServiceName.getPackageName().equals(pkg)) {
mHandler.sendMessage(mHandler.obtainMessage(MSG_PACKAGE_INTENT, intent));
}
}
};
private final String mTag;
private final boolean mDebug;
private final Context mContext;
private final String mSettingKey;
private final Callbacks mCallbacks;
private ComponentName mServiceName;
private SC mServiceConnection;
private boolean mBound;
public ServiceMonitor(String ownerTag, boolean debug,
Context context, String settingKey, Callbacks callbacks) {
mTag = ownerTag + ".ServiceMonitor";
mDebug = debug;
mContext = context;
mSettingKey = settingKey;
mCallbacks = callbacks;
}
public void start() {
// listen for setting changes
ContentResolver cr = mContext.getContentResolver();
cr.registerContentObserver(Settings.Secure.getUriFor(mSettingKey),
false /*notifyForDescendents*/, mSettingObserver, UserHandle.USER_ALL);
// listen for package/component changes
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addDataScheme("package");
mContext.registerReceiver(mBroadcastReceiver, filter);
mHandler.sendEmptyMessage(MSG_START_SERVICE);
}
private ComponentName getComponentNameFromSetting() {
String cn = Settings.Secure.getStringForUser(mContext.getContentResolver(),
mSettingKey, UserHandle.USER_CURRENT);
return cn == null ? null : ComponentName.unflattenFromString(cn);
}
// everything below is called on the handler
private void packageIntent(Intent intent) {
if (mDebug) Log.d(mTag, "packageIntent intent=" + intent
+ " extras=" + bundleToString(intent.getExtras()));
if (Intent.ACTION_PACKAGE_ADDED.equals(intent.getAction())) {
mHandler.sendEmptyMessage(MSG_START_SERVICE);
} else if (Intent.ACTION_PACKAGE_CHANGED.equals(intent.getAction())) {
PackageManager pm = mContext.getPackageManager();
boolean serviceEnabled =
pm.getApplicationEnabledSetting(mServiceName.getPackageName())
!= PackageManager.COMPONENT_ENABLED_STATE_DISABLED
&& pm.getComponentEnabledSetting(mServiceName)
!= PackageManager.COMPONENT_ENABLED_STATE_DISABLED;
if (mBound && !serviceEnabled) {
stopService();
scheduleCheckBound();
} else if (!mBound && serviceEnabled) {
startService();
}
}
}
private void stopService() {
if (mDebug) Log.d(mTag, "stopService");
boolean stopped = mContext.stopService(new Intent().setComponent(mServiceName));
if (mDebug) Log.d(mTag, " stopped=" + stopped);
mContext.unbindService(mServiceConnection);
mBound = false;
}
private void startService() {
mServiceName = getComponentNameFromSetting();
if (mDebug) Log.d(mTag, "startService mServiceName=" + mServiceName);
if (mServiceName == null) {
mBound = false;
mCallbacks.onNoService();
} else {
long delay = mCallbacks.onServiceStartAttempt();
mHandler.sendEmptyMessageDelayed(MSG_CONTINUE_START_SERVICE, delay);
}
}
private void continueStartService() {
if (mDebug) Log.d(mTag, "continueStartService");
Intent intent = new Intent().setComponent(mServiceName);
try {
mServiceConnection = new SC();
mBound = mContext.bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
if (mDebug) Log.d(mTag, "mBound: " + mBound);
} catch (Throwable t) {
Log.w(mTag, "Error binding to service: " + mServiceName, t);
}
if (!mBound) {
mCallbacks.onNoService();
}
}
private void serviceDisconnected(ComponentName serviceName) {
if (mDebug) Log.d(mTag, "serviceDisconnected serviceName=" + serviceName
+ " mServiceName=" + mServiceName);
if (serviceName.equals(mServiceName)) {
mBound = false;
scheduleCheckBound();
}
}
private void checkBound() {
if (mDebug) Log.d(mTag, "checkBound mBound=" + mBound);
if (!mBound) {
startService();
}
}
private void scheduleCheckBound() {
mHandler.removeMessages(MSG_CHECK_BOUND);
mHandler.sendEmptyMessageDelayed(MSG_CHECK_BOUND, RECHECK_DELAY);
}
private static String bundleToString(Bundle bundle) {
if (bundle == null) return null;
StringBuilder sb = new StringBuilder('{');
for (String key : bundle.keySet()) {
if (sb.length() > 1) sb.append(',');
Object v = bundle.get(key);
v = (v instanceof String[]) ? Arrays.asList((String[]) v) : v;
sb.append(key).append('=').append(v);
}
return sb.append('}').toString();
}
}
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