/*
/*
* Copyright (C) 2011 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.emailcommon.service;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.ProviderInfo;
import android.os.AsyncTask;
import android.os.Debug;
import android.os.IBinder;
import android.os.Looper;
import android.os.RemoteException;
import com.android.emailcommon.provider.EmailContent;
import com.android.mail.utils.LogUtils;
/**
* ServiceProxy is a superclass for proxy objects which make a single call to a service. It handles
* connecting to the service, running a task supplied by the subclass when the connection is ready,
* and disconnecting from the service afterwards. ServiceProxy objects cannot be reused (trying to
* do so generates an {@link IllegalStateException}).
*
* Subclasses must override {@link #onConnected} to store the binder. Then, when the subclass wants
* to make a service call, it should call {@link #setTask}, supplying the {@link ProxyTask} that
* should run when the connection is ready. {@link ProxyTask#run} should implement the necessary
* logic to make the call on the service.
*/
public abstract class ServiceProxy {
public static final String EXTRA_FORCE_SHUTDOWN = "ServiceProxy.FORCE_SHUTDOWN";
private static final boolean DEBUG_PROXY = false; // DO NOT CHECK THIS IN SET TO TRUE
private final String mTag;
private final Context mContext;
protected final Intent mIntent;
private ProxyTask mTask;
private String mName = " unnamed";
private final ServiceConnection mConnection = new ProxyConnection();
// Service call timeout (in seconds)
private int mTimeout = 45;
private long mStartTime;
private boolean mTaskSet = false;
private boolean mTaskCompleted = false;
public static Intent getIntentForEmailPackage(Context context, String actionName) {
/**
* We want to scope the intent so that only the Email app will handle it. Unfortunately
* we found that there are many instances where the package name of the Email app is
* not what we expect. The easiest way to find the package of the correct app is to
* see who is the EmailContent.AUTHORITY as there is only one app that can implement
* the content provider for this authority and this is the right app to handle this intent.
*/
final Intent intent = new Intent(EmailContent.EMAIL_PACKAGE_NAME + "." + actionName);
final ProviderInfo info = context.getPackageManager().resolveContentProvider(
EmailContent.AUTHORITY, 0);
if (info != null) {
final String packageName = info.packageName;
intent.setPackage(packageName);
} else {
LogUtils.e(LogUtils.TAG, "Could not find the Email Content Provider");
}
return intent;
}
/**
* This function is called after the proxy connects to the service but before it runs its task.
* Subclasses must override this to store the binder correctly.
* @param binder The service IBinder.
*/
public abstract void onConnected(IBinder binder);
public ServiceProxy(Context _context, Intent _intent) {
mContext = _context;
mIntent = _intent;
mTag = getClass().getSimpleName();
if (Debug.isDebuggerConnected()) {
mTimeout <<= 2;
}
}
private class ProxyConnection implements ServiceConnection {
@Override
public void onServiceConnected(ComponentName name, IBinder binder) {
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Connected: " + name.getShortClassName() + " at " +
(System.currentTimeMillis() - mStartTime) + "ms");
}
// Let subclasses handle the binder.
onConnected(binder);
// Do our work in another thread.
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
try {
mTask.run();
} catch (RemoteException e) {
LogUtils.e(mTag, e, "RemoteException thrown running mTask!");
} finally {
// Make sure that we unbind the mConnection even on exceptions in the
// task provided by the subclass.
try {
// Each ServiceProxy handles just one task, so we unbind after we're
// done with our work.
mContext.unbindService(mConnection);
} catch (RuntimeException e) {
// The exceptions that are thrown here look like IllegalStateException,
// IllegalArgumentException and RuntimeException. Catching
// RuntimeException which get them all. Reasons for these exceptions
// include services that have already been stopped or unbound. This can
// happen if the user ended the activity that was using the service.
// This is harmless, but we've got to catch it.
LogUtils.e(mTag, e,
"RuntimeException when trying to unbind from service");
}
}
mTaskCompleted = true;
synchronized(mConnection) {
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Task " + mName + " completed; disconnecting");
}
mConnection.notify();
}
return null;
}
}.execute();
}
@Override
public void onServiceDisconnected(ComponentName name) {
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Disconnected: " + name.getShortClassName() + " at " +
(System.currentTimeMillis() - mStartTime) + "ms");
}
}
}
protected interface ProxyTask {
public void run() throws RemoteException;
}
public ServiceProxy setTimeout(int secs) {
mTimeout = secs;
return this;
}
public int getTimeout() {
return mTimeout;
}
protected boolean setTask(ProxyTask task, String name) throws IllegalStateException {
if (mTaskSet) {
throw new IllegalStateException("Cannot call setTask twice on the same ServiceProxy.");
}
mTaskSet = true;
mName = name;
mTask = task;
mStartTime = System.currentTimeMillis();
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Bind requested for task " + mName);
}
return mContext.bindService(mIntent, mConnection, Context.BIND_AUTO_CREATE);
}
/**
* Callers that want to wait on the {@link ProxyTask} should call this immediately after calling
* {@link #setTask}. This will wait until the task completes, up to the timeout (which can be
* set with {@link #setTimeout}).
*/
protected void waitForCompletion() {
/*
* onServiceConnected() is always called on the main thread, and we block the current thread
* for up to 10 seconds as a timeout. If we're currently on the main thread,
* onServiceConnected() is not called until our timeout elapses (and the UI is frozen for
* the duration).
*/
if (Looper.myLooper() == Looper.getMainLooper()) {
throw new IllegalStateException("This cannot be called on the main thread.");
}
synchronized (mConnection) {
long time = System.currentTimeMillis();
try {
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Waiting for task " + mName + " to complete...");
}
mConnection.wait(mTimeout * 1000L);
} catch (InterruptedException e) {
// Can be ignored safely
}
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Wait for " + mName +
(mTaskCompleted ? " finished in " : " timed out in ") +
(System.currentTimeMillis() - time) + "ms");
}
}
}
/**
* Connection test; return indicates whether the remote service can be connected to
* @return the result of trying to connect to the remote service
*/
public boolean test() {
try {
return setTask(new ProxyTask() {
@Override
public void run() throws RemoteException {
if (DEBUG_PROXY) {
LogUtils.v(mTag, "Connection test succeeded in " +
(System.currentTimeMillis() - mStartTime) + "ms");
}
}
}, "test");
} catch (Exception e) {
// For any failure, return false.
return false;
}
}
}