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/*
* Copyright (C) 2014 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.nfc;
import java.util.ArrayList;
import java.util.List;
import android.app.ActivityManagerNative;
import android.app.IActivityManager;
import android.app.IProcessObserver;
import android.os.RemoteException;
import android.util.Log;
import android.util.SparseArray;
import android.util.SparseBooleanArray;
public class ForegroundUtils extends IProcessObserver.Stub {
static final boolean DBG = false;
private final String TAG = "ForegroundUtils";
private final IActivityManager mIActivityManager;
private final Object mLock = new Object();
// We need to keep track of the individual PIDs per UID,
// since a single UID may have multiple processes running
// that transition into foreground/background state.
private final SparseArray<SparseBooleanArray> mForegroundUidPids =
new SparseArray<SparseBooleanArray>();
private final SparseArray<List<Callback>> mBackgroundCallbacks =
new SparseArray<List<Callback>>();
private static class Singleton {
private static final ForegroundUtils INSTANCE = new ForegroundUtils();
}
private ForegroundUtils() {
mIActivityManager = ActivityManagerNative.getDefault();
try {
mIActivityManager.registerProcessObserver(this);
} catch (RemoteException e) {
// Should not happen!
Log.e(TAG, "ForegroundUtils: could not get IActivityManager");
}
}
public interface Callback {
void onUidToBackground(int uid);
}
public static ForegroundUtils getInstance() {
return Singleton.INSTANCE;
}
/**
* Checks whether the specified UID has any activities running in the foreground,
* and if it does, registers a callback for when that UID no longer has any foreground
* activities. This is done atomically, so callers can be ensured that they will
* get a callback if this method returns true.
*
* @param callback Callback to be called
* @param uid The UID to be checked
* @return true when the UID has an Activity in the foreground and the callback
* , false otherwise
*/
public boolean registerUidToBackgroundCallback(Callback callback, int uid) {
synchronized (mLock) {
if (!isInForegroundLocked(uid)) {
return false;
}
// This uid is in the foreground; register callback for when it moves
// into the background.
List<Callback> callbacks = mBackgroundCallbacks.get(uid, new ArrayList<Callback>());
callbacks.add(callback);
mBackgroundCallbacks.put(uid, callbacks);
return true;
}
}
/**
* @param uid The UID to be checked
* @return whether the UID has any activities running in the foreground
*/
public boolean isInForeground(int uid) {
synchronized (mLock) {
return isInForegroundLocked(uid);
}
}
/**
* @return a list of UIDs currently in the foreground, or an empty list
* if none are found.
*/
public List<Integer> getForegroundUids() {
ArrayList<Integer> uids = new ArrayList<Integer>(mForegroundUidPids.size());
synchronized (mLock) {
for (int i = 0; i < mForegroundUidPids.size(); i++) {
uids.add(mForegroundUidPids.keyAt(i));
}
}
return uids;
}
private boolean isInForegroundLocked(int uid) {
return mForegroundUidPids.get(uid) != null;
}
private void handleUidToBackground(int uid) {
ArrayList<Callback> pendingCallbacks = null;
synchronized (mLock) {
List<Callback> callbacks = mBackgroundCallbacks.get(uid);
if (callbacks != null) {
pendingCallbacks = new ArrayList<Callback>(callbacks);
// Only call them once
mBackgroundCallbacks.remove(uid);
}
}
// Release lock for callbacks
if (pendingCallbacks != null) {
for (Callback callback : pendingCallbacks) {
callback.onUidToBackground(uid);
}
}
}
@Override
public void onForegroundActivitiesChanged(int pid, int uid,
boolean hasForegroundActivities) throws RemoteException {
boolean uidToBackground = false;
synchronized (mLock) {
SparseBooleanArray foregroundPids = mForegroundUidPids.get(uid,
new SparseBooleanArray());
if (hasForegroundActivities) {
foregroundPids.put(pid, true);
} else {
foregroundPids.delete(pid);
}
if (foregroundPids.size() == 0) {
mForegroundUidPids.remove(uid);
uidToBackground = true;
} else {
mForegroundUidPids.put(uid, foregroundPids);
}
}
if (uidToBackground) {
handleUidToBackground(uid);
}
if (DBG) {
if (DBG) Log.d(TAG, "Foreground changed, PID: " + Integer.toString(pid) + " UID: " +
Integer.toString(uid) + " foreground: " +
hasForegroundActivities);
synchronized (mLock) {
Log.d(TAG, "Foreground UID/PID combinations:");
for (int i = 0; i < mForegroundUidPids.size(); i++) {
int foregroundUid = mForegroundUidPids.keyAt(i);
SparseBooleanArray foregroundPids = mForegroundUidPids.get(foregroundUid);
if (foregroundPids.size() == 0) {
Log.e(TAG, "No PIDS associated with foreground UID!");
}
for (int j = 0; j < foregroundPids.size(); j++)
Log.d(TAG, "UID: " + Integer.toString(foregroundUid) + " PID: " +
Integer.toString(foregroundPids.keyAt(j)));
}
}
}
}
@Override
public void onProcessDied(int pid, int uid) throws RemoteException {
if (DBG) Log.d(TAG, "Process died; UID " + Integer.toString(uid) + " PID " +
Integer.toString(pid));
onForegroundActivitiesChanged(pid, uid, false);
}
@Override
public void onImportanceChanged(int pid, int uid, int importance)
throws RemoteException {
// Don't care
}
}
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