/*
* 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.server.am;
import android.app.ActivityManager;
import android.app.AppGlobals;
import android.content.ComponentName;
import android.content.pm.IPackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Debug;
import android.os.RemoteException;
import android.os.SystemClock;
import android.os.UserHandle;
import android.text.format.DateUtils;
import android.util.ArrayMap;
import android.util.ArraySet;
import android.util.AtomicFile;
import android.util.Slog;
import android.util.SparseArray;
import android.util.Xml;
import android.os.Process;
import com.android.internal.util.FastXmlSerializer;
import com.android.internal.util.XmlUtils;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import libcore.io.IoUtils;
import static com.android.server.am.TaskRecord.INVALID_TASK_ID;
public class TaskPersister {
static final String TAG = "TaskPersister";
static final boolean DEBUG = false;
/** When not flushing don't write out files faster than this */
private static final long INTER_WRITE_DELAY_MS = 500;
/** When not flushing delay this long before writing the first file out. This gives the next
* task being launched a chance to load its resources without this occupying IO bandwidth. */
private static final long PRE_TASK_DELAY_MS = 3000;
/** The maximum number of entries to keep in the queue before draining it automatically. */
private static final int MAX_WRITE_QUEUE_LENGTH = 6;
/** Special value for mWriteTime to mean don't wait, just write */
private static final long FLUSH_QUEUE = -1;
private static final String RECENTS_FILENAME = "_task";
private static final String TASKS_DIRNAME = "recent_tasks";
private static final String TASK_EXTENSION = ".xml";
private static final String IMAGES_DIRNAME = "recent_images";
static final String IMAGE_EXTENSION = ".png";
private static final String TAG_TASK = "task";
static File sImagesDir;
static File sTasksDir;
private final ActivityManagerService mService;
private final ActivityStackSupervisor mStackSupervisor;
private final RecentTasks mRecentTasks;
/** Value determines write delay mode as follows:
* < 0 We are Flushing. No delays between writes until the image queue is drained and all
* tasks needing persisting are written to disk. There is no delay between writes.
* == 0 We are Idle. Next writes will be delayed by #PRE_TASK_DELAY_MS.
* > 0 We are Actively writing. Next write will be at this time. Subsequent writes will be
* delayed by #INTER_WRITE_DELAY_MS. */
private long mNextWriteTime = 0;
private final LazyTaskWriterThread mLazyTaskWriterThread;
private static class WriteQueueItem {}
private static class TaskWriteQueueItem extends WriteQueueItem {
final TaskRecord mTask;
TaskWriteQueueItem(TaskRecord task) {
mTask = task;
}
}
private static class ImageWriteQueueItem extends WriteQueueItem {
final String mFilename;
Bitmap mImage;
ImageWriteQueueItem(String filename, Bitmap image) {
mFilename = filename;
mImage = image;
}
}
ArrayList<WriteQueueItem> mWriteQueue = new ArrayList<WriteQueueItem>();
TaskPersister(File systemDir, ActivityStackSupervisor stackSupervisor,
RecentTasks recentTasks) {
sTasksDir = new File(systemDir, TASKS_DIRNAME);
if (!sTasksDir.exists()) {
if (DEBUG) Slog.d(TAG, "Creating tasks directory " + sTasksDir);
if (!sTasksDir.mkdir()) {
Slog.e(TAG, "Failure creating tasks directory " + sTasksDir);
}
}
sImagesDir = new File(systemDir, IMAGES_DIRNAME);
if (!sImagesDir.exists()) {
if (DEBUG) Slog.d(TAG, "Creating images directory " + sTasksDir);
if (!sImagesDir.mkdir()) {
Slog.e(TAG, "Failure creating images directory " + sImagesDir);
}
}
mStackSupervisor = stackSupervisor;
mService = stackSupervisor.mService;
mRecentTasks = recentTasks;
mLazyTaskWriterThread = new LazyTaskWriterThread("LazyTaskWriterThread");
}
void startPersisting() {
if (!mLazyTaskWriterThread.isAlive()) {
mLazyTaskWriterThread.start();
}
}
private void removeThumbnails(TaskRecord task) {
final String taskString = Integer.toString(task.taskId);
for (int queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) {
final WriteQueueItem item = mWriteQueue.get(queueNdx);
if (item instanceof ImageWriteQueueItem &&
((ImageWriteQueueItem) item).mFilename.startsWith(taskString)) {
if (DEBUG) Slog.d(TAG, "Removing " + ((ImageWriteQueueItem) item).mFilename +
" from write queue");
mWriteQueue.remove(queueNdx);
}
}
}
private void yieldIfQueueTooDeep() {
boolean stall = false;
synchronized (this) {
if (mNextWriteTime == FLUSH_QUEUE) {
stall = true;
}
}
if (stall) {
Thread.yield();
}
}
void wakeup(TaskRecord task, boolean flush) {
synchronized (this) {
if (task != null) {
int queueNdx;
for (queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) {
final WriteQueueItem item = mWriteQueue.get(queueNdx);
if (item instanceof TaskWriteQueueItem &&
((TaskWriteQueueItem) item).mTask == task) {
if (!task.inRecents) {
// This task is being removed.
removeThumbnails(task);
}
break;
}
}
if (queueNdx < 0 && task.isPersistable) {
mWriteQueue.add(new TaskWriteQueueItem(task));
}
} else {
// Dummy.
mWriteQueue.add(new WriteQueueItem());
}
if (flush || mWriteQueue.size() > MAX_WRITE_QUEUE_LENGTH) {
mNextWriteTime = FLUSH_QUEUE;
} else if (mNextWriteTime == 0) {
mNextWriteTime = SystemClock.uptimeMillis() + PRE_TASK_DELAY_MS;
}
if (DEBUG) Slog.d(TAG, "wakeup: task=" + task + " flush=" + flush + " mNextWriteTime="
+ mNextWriteTime + " mWriteQueue.size=" + mWriteQueue.size()
+ " Callers=" + Debug.getCallers(4));
notifyAll();
}
yieldIfQueueTooDeep();
}
void flush() {
synchronized (this) {
mNextWriteTime = FLUSH_QUEUE;
notifyAll();
do {
try {
wait();
} catch (InterruptedException e) {
}
} while (mNextWriteTime == FLUSH_QUEUE);
}
}
void saveImage(Bitmap image, String filename) {
synchronized (this) {
int queueNdx;
for (queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) {
final WriteQueueItem item = mWriteQueue.get(queueNdx);
if (item instanceof ImageWriteQueueItem) {
ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item;
if (imageWriteQueueItem.mFilename.equals(filename)) {
// replace the Bitmap with the new one.
imageWriteQueueItem.mImage = image;
break;
}
}
}
if (queueNdx < 0) {
mWriteQueue.add(new ImageWriteQueueItem(filename, image));
}
if (mWriteQueue.size() > MAX_WRITE_QUEUE_LENGTH) {
mNextWriteTime = FLUSH_QUEUE;
} else if (mNextWriteTime == 0) {
mNextWriteTime = SystemClock.uptimeMillis() + PRE_TASK_DELAY_MS;
}
if (DEBUG) Slog.d(TAG, "saveImage: filename=" + filename + " now=" +
SystemClock.uptimeMillis() + " mNextWriteTime=" +
mNextWriteTime + " Callers=" + Debug.getCallers(4));
notifyAll();
}
yieldIfQueueTooDeep();
}
Bitmap getTaskDescriptionIcon(String filename) {
// See if it is in the write queue
final Bitmap icon = getImageFromWriteQueue(filename);
if (icon != null) {
return icon;
}
return restoreImage(filename);
}
Bitmap getImageFromWriteQueue(String filename) {
synchronized (this) {
for (int queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) {
final WriteQueueItem item = mWriteQueue.get(queueNdx);
if (item instanceof ImageWriteQueueItem) {
ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item;
if (imageWriteQueueItem.mFilename.equals(filename)) {
return imageWriteQueueItem.mImage;
}
}
}
return null;
}
}
private StringWriter saveToXml(TaskRecord task) throws IOException, XmlPullParserException {
if (DEBUG) Slog.d(TAG, "saveToXml: task=" + task);
final XmlSerializer xmlSerializer = new FastXmlSerializer();
StringWriter stringWriter = new StringWriter();
xmlSerializer.setOutput(stringWriter);
if (DEBUG) xmlSerializer.setFeature(
"http://xmlpull.org/v1/doc/features.html#indent-output", true);
// save task
xmlSerializer.startDocument(null, true);
xmlSerializer.startTag(null, TAG_TASK);
task.saveToXml(xmlSerializer);
xmlSerializer.endTag(null, TAG_TASK);
xmlSerializer.endDocument();
xmlSerializer.flush();
return stringWriter;
}
private String fileToString(File file) {
final String newline = System.lineSeparator();
try {
BufferedReader reader = new BufferedReader(new FileReader(file));
StringBuffer sb = new StringBuffer((int) file.length() * 2);
String line;
while ((line = reader.readLine()) != null) {
sb.append(line + newline);
}
reader.close();
return sb.toString();
} catch (IOException ioe) {
Slog.e(TAG, "Couldn't read file " + file.getName());
return null;
}
}
private TaskRecord taskIdToTask(int taskId, ArrayList<TaskRecord> tasks) {
if (taskId < 0) {
return null;
}
for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) {
final TaskRecord task = tasks.get(taskNdx);
if (task.taskId == taskId) {
return task;
}
}
Slog.e(TAG, "Restore affiliation error looking for taskId=" + taskId);
return null;
}
ArrayList<TaskRecord> restoreTasksLocked() {
final ArrayList<TaskRecord> tasks = new ArrayList<TaskRecord>();
ArraySet<Integer> recoveredTaskIds = new ArraySet<Integer>();
File[] recentFiles = sTasksDir.listFiles();
if (recentFiles == null) {
Slog.e(TAG, "Unable to list files from " + sTasksDir);
return tasks;
}
for (int taskNdx = 0; taskNdx < recentFiles.length; ++taskNdx) {
File taskFile = recentFiles[taskNdx];
if (DEBUG) Slog.d(TAG, "restoreTasksLocked: taskFile=" + taskFile.getName());
BufferedReader reader = null;
boolean deleteFile = false;
try {
reader = new BufferedReader(new FileReader(taskFile));
final XmlPullParser in = Xml.newPullParser();
in.setInput(reader);
int event;
while (((event = in.next()) != XmlPullParser.END_DOCUMENT) &&
event != XmlPullParser.END_TAG) {
final String name = in.getName();
if (event == XmlPullParser.START_TAG) {
if (DEBUG) Slog.d(TAG, "restoreTasksLocked: START_TAG name=" + name);
if (TAG_TASK.equals(name)) {
final TaskRecord task =
TaskRecord.restoreFromXml(in, mStackSupervisor);
if (DEBUG) Slog.d(TAG, "restoreTasksLocked: restored task=" +
task);
if (task != null) {
task.isPersistable = true;
// XXX Don't add to write queue... there is no reason to write
// out the stuff we just read, if we don't write it we will
// read the same thing again.
//mWriteQueue.add(new TaskWriteQueueItem(task));
tasks.add(task);
final int taskId = task.taskId;
recoveredTaskIds.add(taskId);
mStackSupervisor.setNextTaskId(taskId);
} else {
Slog.e(TAG, "Unable to restore taskFile=" + taskFile + ": " +
fileToString(taskFile));
}
} else {
Slog.wtf(TAG, "restoreTasksLocked Unknown xml event=" + event +
" name=" + name);
}
}
XmlUtils.skipCurrentTag(in);
}
} catch (Exception e) {
Slog.wtf(TAG, "Unable to parse " + taskFile + ". Error ", e);
Slog.e(TAG, "Failing file: " + fileToString(taskFile));
deleteFile = true;
} finally {
IoUtils.closeQuietly(reader);
if (deleteFile) {
if (DEBUG) Slog.d(TAG, "Deleting file=" + taskFile.getName());
taskFile.delete();
}
}
}
if (!DEBUG) {
removeObsoleteFiles(recoveredTaskIds);
}
// Fixup task affiliation from taskIds
for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) {
final TaskRecord task = tasks.get(taskNdx);
task.setPrevAffiliate(taskIdToTask(task.mPrevAffiliateTaskId, tasks));
task.setNextAffiliate(taskIdToTask(task.mNextAffiliateTaskId, tasks));
}
TaskRecord[] tasksArray = new TaskRecord[tasks.size()];
tasks.toArray(tasksArray);
Arrays.sort(tasksArray, new Comparator<TaskRecord>() {
@Override
public int compare(TaskRecord lhs, TaskRecord rhs) {
final long diff = rhs.mLastTimeMoved - lhs.mLastTimeMoved;
if (diff < 0) {
return -1;
} else if (diff > 0) {
return +1;
} else {
return 0;
}
}
});
return new ArrayList<TaskRecord>(Arrays.asList(tasksArray));
}
private static void removeObsoleteFiles(ArraySet<Integer> persistentTaskIds, File[] files) {
if (DEBUG) Slog.d(TAG, "removeObsoleteFile: persistentTaskIds=" + persistentTaskIds +
" files=" + files);
if (files == null) {
Slog.e(TAG, "File error accessing recents directory (too many files open?).");
return;
}
for (int fileNdx = 0; fileNdx < files.length; ++fileNdx) {
File file = files[fileNdx];
String filename = file.getName();
final int taskIdEnd = filename.indexOf('_');
if (taskIdEnd > 0) {
final int taskId;
try {
taskId = Integer.valueOf(filename.substring(0, taskIdEnd));
if (DEBUG) Slog.d(TAG, "removeObsoleteFile: Found taskId=" + taskId);
} catch (Exception e) {
Slog.wtf(TAG, "removeObsoleteFile: Can't parse file=" + file.getName());
file.delete();
continue;
}
if (!persistentTaskIds.contains(taskId)) {
if (DEBUG) Slog.d(TAG, "removeObsoleteFile: deleting file=" + file.getName());
file.delete();
}
}
}
}
private void removeObsoleteFiles(ArraySet<Integer> persistentTaskIds) {
removeObsoleteFiles(persistentTaskIds, sTasksDir.listFiles());
removeObsoleteFiles(persistentTaskIds, sImagesDir.listFiles());
}
static Bitmap restoreImage(String filename) {
if (DEBUG) Slog.d(TAG, "restoreImage: restoring " + filename);
return BitmapFactory.decodeFile(sImagesDir + File.separator + filename);
}
private class LazyTaskWriterThread extends Thread {
LazyTaskWriterThread(String name) {
super(name);
}
@Override
public void run() {
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
ArraySet<Integer> persistentTaskIds = new ArraySet<Integer>();
while (true) {
// We can't lock mService while holding TaskPersister.this, but we don't want to
// call removeObsoleteFiles every time through the loop, only the last time before
// going to sleep. The risk is that we call removeObsoleteFiles() successively.
final boolean probablyDone;
synchronized (TaskPersister.this) {
probablyDone = mWriteQueue.isEmpty();
}
if (probablyDone) {
if (DEBUG) Slog.d(TAG, "Looking for obsolete files.");
persistentTaskIds.clear();
synchronized (mService) {
if (DEBUG) Slog.d(TAG, "mRecents=" + mRecentTasks);
for (int taskNdx = mRecentTasks.size() - 1; taskNdx >= 0; --taskNdx) {
final TaskRecord task = mRecentTasks.get(taskNdx);
if (DEBUG) Slog.d(TAG, "LazyTaskWriter: task=" + task +
" persistable=" + task.isPersistable);
if ((task.isPersistable || task.inRecents)
&& (task.stack == null || !task.stack.isHomeStack())) {
if (DEBUG) Slog.d(TAG, "adding to persistentTaskIds task=" + task);
persistentTaskIds.add(task.taskId);
} else {
if (DEBUG) Slog.d(TAG,
"omitting from persistentTaskIds task=" + task);
}
}
}
removeObsoleteFiles(persistentTaskIds);
}
// If mNextWriteTime, then don't delay between each call to saveToXml().
final WriteQueueItem item;
synchronized (TaskPersister.this) {
if (mNextWriteTime != FLUSH_QUEUE) {
// The next write we don't have to wait so long.
mNextWriteTime = SystemClock.uptimeMillis() + INTER_WRITE_DELAY_MS;
if (DEBUG) Slog.d(TAG, "Next write time may be in " +
INTER_WRITE_DELAY_MS + " msec. (" + mNextWriteTime + ")");
}
while (mWriteQueue.isEmpty()) {
if (mNextWriteTime != 0) {
mNextWriteTime = 0; // idle.
TaskPersister.this.notifyAll(); // wake up flush() if needed.
}
try {
if (DEBUG) Slog.d(TAG, "LazyTaskWriter: waiting indefinitely.");
TaskPersister.this.wait();
} catch (InterruptedException e) {
}
// Invariant: mNextWriteTime is either FLUSH_QUEUE or PRE_WRITE_DELAY_MS
// from now.
}
item = mWriteQueue.remove(0);
long now = SystemClock.uptimeMillis();
if (DEBUG) Slog.d(TAG, "LazyTaskWriter: now=" + now + " mNextWriteTime=" +
mNextWriteTime + " mWriteQueue.size=" + mWriteQueue.size());
while (now < mNextWriteTime) {
try {
if (DEBUG) Slog.d(TAG, "LazyTaskWriter: waiting " +
(mNextWriteTime - now));
TaskPersister.this.wait(mNextWriteTime - now);
} catch (InterruptedException e) {
}
now = SystemClock.uptimeMillis();
}
// Got something to do.
}
if (item instanceof ImageWriteQueueItem) {
ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item;
final String filename = imageWriteQueueItem.mFilename;
final Bitmap bitmap = imageWriteQueueItem.mImage;
if (DEBUG) Slog.d(TAG, "writing bitmap: filename=" + filename);
FileOutputStream imageFile = null;
try {
imageFile = new FileOutputStream(new File(sImagesDir, filename));
bitmap.compress(Bitmap.CompressFormat.PNG, 100, imageFile);
} catch (Exception e) {
Slog.e(TAG, "saveImage: unable to save " + filename, e);
} finally {
IoUtils.closeQuietly(imageFile);
}
} else if (item instanceof TaskWriteQueueItem) {
// Write out one task.
StringWriter stringWriter = null;
TaskRecord task = ((TaskWriteQueueItem) item).mTask;
if (DEBUG) Slog.d(TAG, "Writing task=" + task);
synchronized (mService) {
if (task.inRecents) {
// Still there.
try {
if (DEBUG) Slog.d(TAG, "Saving task=" + task);
stringWriter = saveToXml(task);
} catch (IOException e) {
} catch (XmlPullParserException e) {
}
}
}
if (stringWriter != null) {
// Write out xml file while not holding mService lock.
FileOutputStream file = null;
AtomicFile atomicFile = null;
try {
atomicFile = new AtomicFile(new File(sTasksDir, String.valueOf(
task.taskId) + RECENTS_FILENAME + TASK_EXTENSION));
file = atomicFile.startWrite();
file.write(stringWriter.toString().getBytes());
file.write('\n');
atomicFile.finishWrite(file);
} catch (IOException e) {
if (file != null) {
atomicFile.failWrite(file);
}
Slog.e(TAG, "Unable to open " + atomicFile + " for persisting. " +
e);
}
}
}
}
}
}
}