1 /* 2 /* 3 * Copyright (C) 2011 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package com.android.emailcommon.service; 19 20 import android.content.ComponentName; 21 import android.content.Context; 22 import android.content.Intent; 23 import android.content.ServiceConnection; 24 import android.content.pm.ProviderInfo; 25 import android.os.AsyncTask; 26 import android.os.Debug; 27 import android.os.IBinder; 28 import android.os.Looper; 29 import android.os.RemoteException; 30 31 import com.android.emailcommon.provider.EmailContent; 32 import com.android.mail.utils.LogUtils; 33 34 /** 35 * ServiceProxy is a superclass for proxy objects which make a single call to a service. It handles 36 * connecting to the service, running a task supplied by the subclass when the connection is ready, 37 * and disconnecting from the service afterwards. ServiceProxy objects cannot be reused (trying to 38 * do so generates an {@link IllegalStateException}). 39 * 40 * Subclasses must override {@link #onConnected} to store the binder. Then, when the subclass wants 41 * to make a service call, it should call {@link #setTask}, supplying the {@link ProxyTask} that 42 * should run when the connection is ready. {@link ProxyTask#run} should implement the necessary 43 * logic to make the call on the service. 44 */ 45 46 public abstract class ServiceProxy { 47 public static final String EXTRA_FORCE_SHUTDOWN = "ServiceProxy.FORCE_SHUTDOWN"; 48 49 private static final boolean DEBUG_PROXY = false; // DO NOT CHECK THIS IN SET TO TRUE 50 private final String mTag; 51 52 private final Context mContext; 53 protected final Intent mIntent; 54 private ProxyTask mTask; 55 private String mName = " unnamed"; 56 private final ServiceConnection mConnection = new ProxyConnection(); 57 // Service call timeout (in seconds) 58 private int mTimeout = 45; 59 private long mStartTime; 60 private boolean mTaskSet = false; 61 private boolean mTaskCompleted = false; 62 getIntentForEmailPackage(Context context, String actionName)63 public static Intent getIntentForEmailPackage(Context context, String actionName) { 64 /** 65 * We want to scope the intent so that only the Email app will handle it. Unfortunately 66 * we found that there are many instances where the package name of the Email app is 67 * not what we expect. The easiest way to find the package of the correct app is to 68 * see who is the EmailContent.AUTHORITY as there is only one app that can implement 69 * the content provider for this authority and this is the right app to handle this intent. 70 */ 71 final Intent intent = new Intent(EmailContent.EMAIL_PACKAGE_NAME + "." + actionName); 72 final ProviderInfo info = context.getPackageManager().resolveContentProvider( 73 EmailContent.AUTHORITY, 0); 74 if (info != null) { 75 final String packageName = info.packageName; 76 intent.setPackage(packageName); 77 } else { 78 LogUtils.e(LogUtils.TAG, "Could not find the Email Content Provider"); 79 } 80 return intent; 81 } 82 83 /** 84 * This function is called after the proxy connects to the service but before it runs its task. 85 * Subclasses must override this to store the binder correctly. 86 * @param binder The service IBinder. 87 */ onConnected(IBinder binder)88 public abstract void onConnected(IBinder binder); 89 ServiceProxy(Context _context, Intent _intent)90 public ServiceProxy(Context _context, Intent _intent) { 91 mContext = _context; 92 mIntent = _intent; 93 mTag = getClass().getSimpleName(); 94 if (Debug.isDebuggerConnected()) { 95 mTimeout <<= 2; 96 } 97 } 98 99 private class ProxyConnection implements ServiceConnection { 100 @Override onServiceConnected(ComponentName name, IBinder binder)101 public void onServiceConnected(ComponentName name, IBinder binder) { 102 if (DEBUG_PROXY) { 103 LogUtils.v(mTag, "Connected: " + name.getShortClassName() + " at " + 104 (System.currentTimeMillis() - mStartTime) + "ms"); 105 } 106 107 // Let subclasses handle the binder. 108 onConnected(binder); 109 110 // Do our work in another thread. 111 new AsyncTask<Void, Void, Void>() { 112 @Override 113 protected Void doInBackground(Void... params) { 114 try { 115 mTask.run(); 116 } catch (RemoteException e) { 117 LogUtils.e(mTag, e, "RemoteException thrown running mTask!"); 118 } finally { 119 // Make sure that we unbind the mConnection even on exceptions in the 120 // task provided by the subclass. 121 try { 122 // Each ServiceProxy handles just one task, so we unbind after we're 123 // done with our work. 124 mContext.unbindService(mConnection); 125 } catch (RuntimeException e) { 126 // The exceptions that are thrown here look like IllegalStateException, 127 // IllegalArgumentException and RuntimeException. Catching 128 // RuntimeException which get them all. Reasons for these exceptions 129 // include services that have already been stopped or unbound. This can 130 // happen if the user ended the activity that was using the service. 131 // This is harmless, but we've got to catch it. 132 LogUtils.e(mTag, e, 133 "RuntimeException when trying to unbind from service"); 134 } 135 } 136 mTaskCompleted = true; 137 synchronized(mConnection) { 138 if (DEBUG_PROXY) { 139 LogUtils.v(mTag, "Task " + mName + " completed; disconnecting"); 140 } 141 mConnection.notify(); 142 } 143 return null; 144 } 145 }.execute(); 146 } 147 148 @Override onServiceDisconnected(ComponentName name)149 public void onServiceDisconnected(ComponentName name) { 150 if (DEBUG_PROXY) { 151 LogUtils.v(mTag, "Disconnected: " + name.getShortClassName() + " at " + 152 (System.currentTimeMillis() - mStartTime) + "ms"); 153 } 154 } 155 } 156 157 protected interface ProxyTask { run()158 public void run() throws RemoteException; 159 } 160 setTimeout(int secs)161 public ServiceProxy setTimeout(int secs) { 162 mTimeout = secs; 163 return this; 164 } 165 getTimeout()166 public int getTimeout() { 167 return mTimeout; 168 } 169 setTask(ProxyTask task, String name)170 protected boolean setTask(ProxyTask task, String name) throws IllegalStateException { 171 if (mTaskSet) { 172 throw new IllegalStateException("Cannot call setTask twice on the same ServiceProxy."); 173 } 174 mTaskSet = true; 175 mName = name; 176 mTask = task; 177 mStartTime = System.currentTimeMillis(); 178 if (DEBUG_PROXY) { 179 LogUtils.v(mTag, "Bind requested for task " + mName); 180 } 181 return mContext.bindService(mIntent, mConnection, Context.BIND_AUTO_CREATE); 182 } 183 184 /** 185 * Callers that want to wait on the {@link ProxyTask} should call this immediately after calling 186 * {@link #setTask}. This will wait until the task completes, up to the timeout (which can be 187 * set with {@link #setTimeout}). 188 */ waitForCompletion()189 protected void waitForCompletion() { 190 /* 191 * onServiceConnected() is always called on the main thread, and we block the current thread 192 * for up to 10 seconds as a timeout. If we're currently on the main thread, 193 * onServiceConnected() is not called until our timeout elapses (and the UI is frozen for 194 * the duration). 195 */ 196 if (Looper.myLooper() == Looper.getMainLooper()) { 197 throw new IllegalStateException("This cannot be called on the main thread."); 198 } 199 200 synchronized (mConnection) { 201 long time = System.currentTimeMillis(); 202 try { 203 if (DEBUG_PROXY) { 204 LogUtils.v(mTag, "Waiting for task " + mName + " to complete..."); 205 } 206 mConnection.wait(mTimeout * 1000L); 207 } catch (InterruptedException e) { 208 // Can be ignored safely 209 } 210 if (DEBUG_PROXY) { 211 LogUtils.v(mTag, "Wait for " + mName + 212 (mTaskCompleted ? " finished in " : " timed out in ") + 213 (System.currentTimeMillis() - time) + "ms"); 214 } 215 } 216 } 217 218 /** 219 * Connection test; return indicates whether the remote service can be connected to 220 * @return the result of trying to connect to the remote service 221 */ test()222 public boolean test() { 223 try { 224 return setTask(new ProxyTask() { 225 @Override 226 public void run() throws RemoteException { 227 if (DEBUG_PROXY) { 228 LogUtils.v(mTag, "Connection test succeeded in " + 229 (System.currentTimeMillis() - mStartTime) + "ms"); 230 } 231 } 232 }, "test"); 233 } catch (Exception e) { 234 // For any failure, return false. 235 return false; 236 } 237 } 238 } 239