replicant-packages_apps_Email/src/com/android/email/service/AttachmentService.java

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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.email.service;
import android.accounts.AccountManager;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.ConnectivityManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.SystemClock;
import android.text.format.DateUtils;
import com.android.email.AttachmentInfo;
import com.android.email.EmailConnectivityManager;
import com.android.email.NotificationController;
import com.android.emailcommon.provider.Account;
import com.android.emailcommon.provider.EmailContent;
import com.android.emailcommon.provider.EmailContent.Attachment;
import com.android.emailcommon.provider.EmailContent.AttachmentColumns;
import com.android.emailcommon.provider.EmailContent.Message;
import com.android.emailcommon.service.EmailServiceProxy;
import com.android.emailcommon.service.EmailServiceStatus;
import com.android.emailcommon.service.IEmailServiceCallback;
import com.android.emailcommon.utility.AttachmentUtilities;
import com.android.emailcommon.utility.Utility;
import com.android.mail.providers.UIProvider.AttachmentState;
import com.android.mail.utils.LogUtils;
import com.google.common.annotations.VisibleForTesting;
import java.io.File;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
public class AttachmentService extends Service implements Runnable {
// For logging.
public static final String LOG_TAG = "AttachmentService";
// Minimum wait time before retrying a download that failed due to connection error
private static final long CONNECTION_ERROR_RETRY_MILLIS = 10 * DateUtils.SECOND_IN_MILLIS;
// Number of retries before we start delaying between
private static final long CONNECTION_ERROR_DELAY_THRESHOLD = 5;
// Maximum time to retry for connection errors.
private static final long CONNECTION_ERROR_MAX_RETRIES = 10;
// Our idle time, waiting for notifications; this is something of a failsafe
private static final int PROCESS_QUEUE_WAIT_TIME = 30 * ((int)DateUtils.MINUTE_IN_MILLIS);
// How long we'll wait for a callback before canceling a download and retrying
private static final int CALLBACK_TIMEOUT = 30 * ((int)DateUtils.SECOND_IN_MILLIS);
// Try to download an attachment in the background this many times before giving up
private static final int MAX_DOWNLOAD_RETRIES = 5;
static final int PRIORITY_NONE = -1;
// High priority is for user requests
static final int PRIORITY_FOREGROUND = 0;
static final int PRIORITY_HIGHEST = PRIORITY_FOREGROUND;
// Normal priority is for forwarded downloads in outgoing mail
static final int PRIORITY_SEND_MAIL = 1;
// Low priority will be used for opportunistic downloads
static final int PRIORITY_BACKGROUND = 2;
static final int PRIORITY_LOWEST = PRIORITY_BACKGROUND;
// Minimum free storage in order to perform prefetch (25% of total memory)
private static final float PREFETCH_MINIMUM_STORAGE_AVAILABLE = 0.25F;
// Maximum prefetch storage (also 25% of total memory)
private static final float PREFETCH_MAXIMUM_ATTACHMENT_STORAGE = 0.25F;
// We can try various values here; I think 2 is completely reasonable as a first pass
private static final int MAX_SIMULTANEOUS_DOWNLOADS = 2;
// Limit on the number of simultaneous downloads per account
// Note that a limit of 1 is currently enforced by both Services (MailService and Controller)
private static final int MAX_SIMULTANEOUS_DOWNLOADS_PER_ACCOUNT = 1;
// Limit on the number of attachments we'll check for background download
private static final int MAX_ATTACHMENTS_TO_CHECK = 25;
private static final String EXTRA_ATTACHMENT = "com.android.email.AttachmentService.attachment";
// This callback is invoked by the various service implementations to give us download progress
// since those modules are responsible for the actual download.
private final ServiceCallback mServiceCallback = new ServiceCallback();
// sRunningService is only set in the UI thread; it's visibility elsewhere is guaranteed
// by the use of "volatile"
static volatile AttachmentService sRunningService = null;
// Signify that we are being shut down & destroyed.
private volatile boolean mStop = false;
Context mContext;
EmailConnectivityManager mConnectivityManager;
final AttachmentWatchdog mWatchdog = new AttachmentWatchdog();
private final Object mLock = new Object();
// A map of attachment storage used per account as we have account based maximums to follow.
// NOTE: This map is not kept current in terms of deletions (i.e. it stores the last calculated
// amount plus the size of any new attachments loaded). If and when we reach the per-account
// limit, we recalculate the actual usage
final ConcurrentHashMap<Long, Long> mAttachmentStorageMap = new ConcurrentHashMap<Long, Long>();
// A map of attachment ids to the number of failed attempts to download the attachment
// NOTE: We do not want to persist this. This allows us to retry background downloading
// if any transient network errors are fixed & and the app is restarted
final ConcurrentHashMap<Long, Integer> mAttachmentFailureMap = new ConcurrentHashMap<Long, Integer>();
// Keeps tracks of downloads in progress based on an attachment ID to DownloadRequest mapping.
final ConcurrentHashMap<Long, DownloadRequest> mDownloadsInProgress =
new ConcurrentHashMap<Long, DownloadRequest>();
final DownloadQueue mDownloadQueue = new DownloadQueue();
/**
* This class is used to contain the details and state of a particular request to download
* an attachment. These objects are constructed and either placed in the {@link DownloadQueue}
* or in the in-progress map used to keep track of downloads that are currently happening
* in the system
*/
static class DownloadRequest {
// Details of the request.
final int mPriority;
final long mTime;
final long mAttachmentId;
final long mMessageId;
final long mAccountId;
// Status of the request.
boolean mInProgress = false;
int mLastStatusCode;
int mLastProgress;
long mLastCallbackTime;
long mStartTime;
long mRetryCount;
long mRetryStartTime;
/**
* This constructor is mainly used for tests
* @param attPriority The priority of this attachment
* @param attId The id of the row in the attachment table.
*/
@VisibleForTesting
DownloadRequest(final int attPriority, final long attId) {
// This constructor should only be used for unit tests.
mTime = SystemClock.elapsedRealtime();
mPriority = attPriority;
mAttachmentId = attId;
mAccountId = -1;
mMessageId = -1;
}
private DownloadRequest(final Context context, final Attachment attachment) {
mAttachmentId = attachment.mId;
final Message msg = Message.restoreMessageWithId(context, attachment.mMessageKey);
if (msg != null) {
mAccountId = msg.mAccountKey;
mMessageId = msg.mId;
} else {
mAccountId = mMessageId = -1;
}
mPriority = getPriority(attachment);
mTime = SystemClock.elapsedRealtime();
}
private DownloadRequest(final DownloadRequest orig, final long newTime) {
mPriority = orig.mPriority;
mAttachmentId = orig.mAttachmentId;
mMessageId = orig.mMessageId;
mAccountId = orig.mAccountId;
mTime = newTime;
mInProgress = orig.mInProgress;
mLastStatusCode = orig.mLastStatusCode;
mLastProgress = orig.mLastProgress;
mLastCallbackTime = orig.mLastCallbackTime;
mStartTime = orig.mStartTime;
mRetryCount = orig.mRetryCount;
mRetryStartTime = orig.mRetryStartTime;
}
@Override
public int hashCode() {
return (int)mAttachmentId;
}
/**
* Two download requests are equals if their attachment id's are equals
*/
@Override
public boolean equals(final Object object) {
if (!(object instanceof DownloadRequest)) return false;
final DownloadRequest req = (DownloadRequest)object;
return req.mAttachmentId == mAttachmentId;
}
}
/**
* This class is used to organize the various download requests that are pending.
* We need a class that allows us to prioritize a collection of {@link DownloadRequest} objects
* while being able to pull off request with the highest priority but we also need
* to be able to find a particular {@link DownloadRequest} by id or by reference for retrieval.
* Bonus points for an implementation that does not require an iterator to accomplish its tasks
* as we can avoid pesky ConcurrentModificationException when one thread has the iterator
* and another thread modifies the collection.
*/
static class DownloadQueue {
private final int DEFAULT_SIZE = 10;
// For synchronization
private final Object mLock = new Object();
/**
* Comparator class for the download set; we first compare by priority. Requests with equal
* priority are compared by the time the request was created (older requests come first)
*/
private static class DownloadComparator implements Comparator<DownloadRequest> {
@Override
public int compare(DownloadRequest req1, DownloadRequest req2) {
int res;
if (req1.mPriority != req2.mPriority) {
res = (req1.mPriority < req2.mPriority) ? -1 : 1;
} else {
if (req1.mTime == req2.mTime) {
res = 0;
} else {
res = (req1.mTime < req2.mTime) ? -1 : 1;
}
}
return res;
}
}
// For prioritization of DownloadRequests.
final PriorityQueue<DownloadRequest> mRequestQueue =
new PriorityQueue<DownloadRequest>(DEFAULT_SIZE, new DownloadComparator());
// Secondary collection to quickly find objects w/o the help of an iterator.
// This class should be kept in lock step with the priority queue.
final ConcurrentHashMap<Long, DownloadRequest> mRequestMap = new ConcurrentHashMap<Long, DownloadRequest>();
/**
* This function will add the request to our collections if it does not already
* exist. If it does exist, the function will silently succeed.
* @param request The {@link DownloadRequest} that should be added to our queue
* @return true if it was added (or already exists), false otherwise
*/
public boolean addRequest(final DownloadRequest request)
throws NullPointerException {
// It is key to keep the map and queue in lock step
if (request == null) {
// We can't add a null entry into the queue so let's throw what the underlying
// data structure would throw.
throw new NullPointerException();
}
final long requestId = request.mAttachmentId;
if (requestId < 0) {
// Invalid request
LogUtils.wtf(AttachmentService.LOG_TAG,
"Adding a DownloadRequest with an invalid id");
return false;
}
synchronized (mLock) {
// Check to see if this request is is already in the queue
final boolean exists = mRequestMap.containsKey(requestId);
if (!exists) {
mRequestQueue.offer(request);
mRequestMap.put(requestId, request);
}
}
return true;
}
/**
* This function will remove the specified request from the internal collections.
* @param request The {@link DownloadRequest} that should be removed from our queue
* @return true if it was removed or the request was invalid (meaning that the request
* is not in our queue), false otherwise.
*/
public boolean removeRequest(final DownloadRequest request) {
if (request == null) {
// If it is invalid, its not in the queue.
return true;
}
final boolean result;
synchronized (mLock) {
// It is key to keep the map and queue in lock step
result = mRequestQueue.remove(request);
if (result) {
mRequestMap.remove(request.mAttachmentId);
}
return result;
}
}
/**
* Return the next request from our queue.
* @return The next {@link DownloadRequest} object or null if the queue is empty
*/
public DownloadRequest getNextRequest() {
// It is key to keep the map and queue in lock step
final DownloadRequest returnRequest;
synchronized (mLock) {
returnRequest = mRequestQueue.poll();
if (returnRequest != null) {
final long requestId = returnRequest.mAttachmentId;
mRequestMap.remove(requestId);
}
}
return returnRequest;
}
/**
* Return the {@link DownloadRequest} with the given ID (attachment ID)
* @param requestId The ID of the request in question
* @return The associated {@link DownloadRequest} object or null if it does not exist
*/
public DownloadRequest findRequestById(final long requestId) {
if (requestId < 0) {
return null;
}
synchronized (mLock) {
return mRequestMap.get(requestId);
}
}
public int getSize() {
synchronized (mLock) {
return mRequestMap.size();
}
}
public boolean isEmpty() {
synchronized (mLock) {
return mRequestMap.isEmpty();
}
}
}
/**
* Watchdog alarm receiver; responsible for making sure that downloads in progress are not
* stalled, as determined by the timing of the most recent service callback
*/
public static class AttachmentWatchdog extends BroadcastReceiver {
// How often our watchdog checks for callback timeouts
private static final int WATCHDOG_CHECK_INTERVAL = 20 * ((int)DateUtils.SECOND_IN_MILLIS);
public static final String EXTRA_CALLBACK_TIMEOUT = "callback_timeout";
private PendingIntent mWatchdogPendingIntent;
public void setWatchdogAlarm(final Context context, final long delay,
final int callbackTimeout) {
// Lazily initialize the pending intent
if (mWatchdogPendingIntent == null) {
Intent intent = new Intent(context, AttachmentWatchdog.class);
intent.putExtra(EXTRA_CALLBACK_TIMEOUT, callbackTimeout);
mWatchdogPendingIntent =
PendingIntent.getBroadcast(context, 0, intent, 0);
}
// Set the alarm
final AlarmManager am = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + delay,
mWatchdogPendingIntent);
}
public void setWatchdogAlarm(final Context context) {
// Call the real function with default values.
setWatchdogAlarm(context, WATCHDOG_CHECK_INTERVAL, CALLBACK_TIMEOUT);
}
@Override
public void onReceive(final Context context, final Intent intent) {
final int callbackTimeout = intent.getIntExtra(EXTRA_CALLBACK_TIMEOUT,
CALLBACK_TIMEOUT);
new Thread(new Runnable() {
@Override
public void run() {
final AttachmentService service = AttachmentService.sRunningService;
if (service != null) {
// If our service instance is gone, just leave
if (service.mStop) {
return;
}
// Get the timeout time from the intent.
watchdogAlarm(service, callbackTimeout);
}
}
}, "AttachmentService AttachmentWatchdog").start();
}
/**
* Watchdog for downloads; we use this in case we are hanging on a download, which might
* have failed silently (the connection dropped, for example)
*/
void watchdogAlarm(final AttachmentService service, final int callbackTimeout) {
final long now = System.currentTimeMillis();
// We want to iterate on each of the downloads that are currently in progress and
// cancel the ones that seem to be taking too long.
final Collection<DownloadRequest> inProgressRequests = service.getInProgressDownloads();
for (DownloadRequest req: inProgressRequests) {
// Check how long it's been since receiving a callback
final long timeSinceCallback = now - req.mLastCallbackTime;
if (timeSinceCallback > callbackTimeout) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Download of " + req.mAttachmentId + " timed out");
}
service.cancelDownload(req);
// TODO: Should we also mark the attachment as failed at this point in time?
}
}
// Check whether we can start new downloads...
if (service.isConnected()) {
service.processQueue();
}
if (service.areDownloadsInProgress()) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "Reschedule watchdog...");
}
setWatchdogAlarm(service);
}
}
}
boolean isConnected() {
if (mConnectivityManager != null) {
return mConnectivityManager.hasConnectivity();
}
return false;
}
Collection<DownloadRequest> getInProgressDownloads() {
return mDownloadsInProgress.values();
}
boolean areDownloadsInProgress() {
return !mDownloadsInProgress.isEmpty();
}
/**
* Set the bits in the provider to mark this download as failed.
* @param att The attachment that failed to download.
*/
void markAttachmentAsFailed(final Attachment att) {
final ContentValues cv = new ContentValues();
final int flags = Attachment.FLAG_DOWNLOAD_FORWARD | Attachment.FLAG_DOWNLOAD_USER_REQUEST;
cv.put(AttachmentColumns.FLAGS, att.mFlags &= ~flags);
cv.put(AttachmentColumns.UI_STATE, AttachmentState.FAILED);
att.update(mContext, cv);
}
/**
* onChange is called by the AttachmentReceiver upon receipt of a valid notification from
* EmailProvider that an attachment has been inserted or modified. It's not strictly
* necessary that we detect a deleted attachment, as the code always checks for the
* existence of an attachment before acting on it.
*/
public synchronized void onChange(final Context context, final Attachment att) {
DownloadRequest req = mDownloadQueue.findRequestById(att.mId);
final long priority = getPriority(att);
if (priority == PRIORITY_NONE) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Attachment changed: " + att.mId);
}
// In this case, there is no download priority for this attachment
if (req != null) {
// If it exists in the map, remove it
// NOTE: We don't yet support deleting downloads in progress
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Attachment " + att.mId + " was in queue, removing");
}
mDownloadQueue.removeRequest(req);
}
} else {
// Ignore changes that occur during download
if (mDownloadsInProgress.containsKey(att.mId)) return;
// If this is new, add the request to the queue
if (req == null) {
req = new DownloadRequest(context, att);
final AttachmentInfo attachInfo = new AttachmentInfo(context, att);
if (!attachInfo.isEligibleForDownload()) {
// We can't download this file due to policy, depending on what type
// of request we received, we handle the response differently.
if (((att.mFlags & Attachment.FLAG_DOWNLOAD_USER_REQUEST) != 0) ||
((att.mFlags & Attachment.FLAG_POLICY_DISALLOWS_DOWNLOAD) != 0)) {
// There are a couple of situations where we will not even allow this
// request to go in the queue because we can already process it as a
// failure.
// 1. The user explictly wants to download this attachment from the
// email view but they should not be able to...either because there is
// no app to view it or because its been marked as a policy violation.
// 2. The user is forwarding an email and the attachment has been
// marked as a policy violation. If the attachment is non viewable
// that is OK for forwarding a message so we'll let it pass through
markAttachmentAsFailed(att);
return;
}
// If we get this far it a forward of an attachment that is only
// ineligible because we can't view it or process it. Not because we
// can't download it for policy reasons. Let's let this go through because
// the final recipient of this forward email might be able to process it.
}
mDownloadQueue.addRequest(req);
}
// If the request already existed, we'll update the priority (so that the time is
// up-to-date); otherwise, we create a new request
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Download queued for attachment " + att.mId + ", class " +
req.mPriority + ", priority time " + req.mTime);
}
}
// Process the queue if we're in a wait
kick();
}
/**
* Run through the AttachmentMap and find DownloadRequests that can be executed, enforcing
* the limit on maximum downloads
*/
synchronized void processQueue() {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Checking attachment queue, " + mDownloadQueue.getSize()
+ " entries");
}
while (mDownloadsInProgress.size() < MAX_SIMULTANEOUS_DOWNLOADS) {
final DownloadRequest req = mDownloadQueue.getNextRequest();
if (req == null) {
// No more queued requests? We are done for now.
break;
}
// Enforce per-account limit here
if (downloadsForAccount(req.mAccountId) >= MAX_SIMULTANEOUS_DOWNLOADS_PER_ACCOUNT) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Skip #" + req.mAttachmentId + "; maxed for acct #" +
req.mAccountId);
}
continue;
} else if (Attachment.restoreAttachmentWithId(mContext, req.mAttachmentId) == null) {
continue;
}
if (!req.mInProgress) {
final long currentTime = SystemClock.elapsedRealtime();
if (req.mRetryCount > 0 && req.mRetryStartTime > currentTime) {
LogUtils.d(LOG_TAG, "== waiting to retry attachment %d", req.mAttachmentId);
mWatchdog.setWatchdogAlarm(mContext, CONNECTION_ERROR_RETRY_MILLIS,
CALLBACK_TIMEOUT);
continue;
}
// TODO: We try to gate ineligible downloads from entering the queue but its
// always possible that they made it in here regardless in the future. In a
// perfect world, we would make it bullet proof with a check for eligibility
// here instead/also.
tryStartDownload(req);
}
}
// Check our ability to be opportunistic regarding background downloads.
final EmailConnectivityManager ecm = mConnectivityManager;
if ((ecm == null) || !ecm.isAutoSyncAllowed() ||
(ecm.getActiveNetworkType() != ConnectivityManager.TYPE_WIFI)) {
// Only prefetch if it if connectivity is available, prefetch is enabled
// and we are on WIFI
return;
}
// Then, try opportunistic download of appropriate attachments
final int backgroundDownloads = MAX_SIMULTANEOUS_DOWNLOADS - mDownloadsInProgress.size();
if ((backgroundDownloads + 1) >= MAX_SIMULTANEOUS_DOWNLOADS) {
// We want to leave one spot open for a user requested download that we haven't
// started processing yet.
return;
}
// We'll load up the newest 25 attachments that aren't loaded or queued
// TODO: We are always looking for MAX_ATTACHMENTS_TO_CHECK, shouldn't this be
// backgroundDownloads instead? We should fix and test this.
final Uri lookupUri = EmailContent.uriWithLimit(Attachment.CONTENT_URI,
MAX_ATTACHMENTS_TO_CHECK);
final Cursor c = mContext.getContentResolver().query(lookupUri,
Attachment.CONTENT_PROJECTION,
EmailContent.Attachment.PRECACHE_INBOX_SELECTION,
null, AttachmentColumns._ID + " DESC");
File cacheDir = mContext.getCacheDir();
try {
while (c.moveToNext()) {
final Attachment att = new Attachment();
att.restore(c);
final Account account = Account.restoreAccountWithId(mContext, att.mAccountKey);
if (account == null) {
// Clean up this orphaned attachment; there's no point in keeping it
// around; then try to find another one
EmailContent.delete(mContext, Attachment.CONTENT_URI, att.mId);
} else {
// Check that the attachment meets system requirements for download
// Note that there couple be policy that does not allow this attachment
// to be downloaded.
final AttachmentInfo info = new AttachmentInfo(mContext, att);
if (info.isEligibleForDownload()) {
// Either the account must be able to prefetch or this must be
// an inline attachment.
if (att.mContentId != null ||
(canPrefetchForAccount(account, cacheDir))) {
final Integer tryCount = mAttachmentFailureMap.get(att.mId);
if (tryCount != null && tryCount > MAX_DOWNLOAD_RETRIES) {
// move onto the next attachment
continue;
}
// Start this download and we're done
final DownloadRequest req = new DownloadRequest(mContext, att);
tryStartDownload(req);
break;
}
} else {
// If this attachment was ineligible for download
// because of policy related issues, its flags would be set to
// FLAG_POLICY_DISALLOWS_DOWNLOAD and would not show up in the
// query results. We are most likely here for other reasons such
// as the inability to view the attachment. In that case, let's just
// skip it for now.
LogUtils.e(LOG_TAG, "== skip attachment %d, it is ineligible", att.mId);
}
}
}
} finally {
c.close();
}
}
/**
* Count the number of running downloads in progress for this account
* @param accountId the id of the account
* @return the count of running downloads
*/
synchronized int downloadsForAccount(final long accountId) {
int count = 0;
for (final DownloadRequest req: mDownloadsInProgress.values()) {
if (req.mAccountId == accountId) {
count++;
}
}
return count;
}
/**
* Attempt to execute the DownloadRequest, enforcing the maximum downloads per account
* parameter
* @param req the DownloadRequest
* @return whether or not the download was started
*/
synchronized boolean tryStartDownload(final DownloadRequest req) {
final EmailServiceProxy service = EmailServiceUtils.getServiceForAccount(
AttachmentService.this, req.mAccountId);
// Do not download the same attachment multiple times
boolean alreadyInProgress = mDownloadsInProgress.get(req.mAttachmentId) != null;
if (alreadyInProgress) return false;
try {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, ">> Starting download for attachment #" + req.mAttachmentId);
}
startDownload(service, req);
} catch (RemoteException e) {
// TODO: Consider whether we need to do more in this case...
// For now, fix up our data to reflect the failure
cancelDownload(req);
}
return true;
}
/**
* Do the work of starting an attachment download using the EmailService interface, and
* set our watchdog alarm
*
* @param service the service handling the download
* @param req the DownloadRequest
* @throws RemoteException
*/
private void startDownload(final EmailServiceProxy service, final DownloadRequest req)
throws RemoteException {
req.mStartTime = System.currentTimeMillis();
req.mInProgress = true;
mDownloadsInProgress.put(req.mAttachmentId, req);
service.loadAttachment(mServiceCallback, req.mAccountId, req.mAttachmentId,
req.mPriority != PRIORITY_FOREGROUND);
mWatchdog.setWatchdogAlarm(mContext);
}
synchronized void cancelDownload(final DownloadRequest req) {
LogUtils.d(LOG_TAG, "cancelDownload #%d", req.mAttachmentId);
req.mInProgress = false;
mDownloadsInProgress.remove(req.mAttachmentId);
// Remove the download from our queue, and then decide whether or not to add it back.
mDownloadQueue.removeRequest(req);
req.mRetryCount++;
if (req.mRetryCount > CONNECTION_ERROR_MAX_RETRIES) {
LogUtils.d(LOG_TAG, "too many failures, giving up");
} else {
LogUtils.d(LOG_TAG, "moving to end of queue, will retry");
// The time field of DownloadRequest is final, because it's unsafe to change it
// as long as the DownloadRequest is in the DownloadSet. It's needed for the
// comparator, so changing time would make the request unfindable.
// Instead, we'll create a new DownloadRequest with an updated time.
// This will sort at the end of the set.
final DownloadRequest newReq = new DownloadRequest(req, SystemClock.elapsedRealtime());
mDownloadQueue.addRequest(newReq);
}
}
/**
* Called when a download is finished; we get notified of this via our EmailServiceCallback
* @param attachmentId the id of the attachment whose download is finished
* @param statusCode the EmailServiceStatus code returned by the Service
*/
synchronized void endDownload(final long attachmentId, final int statusCode) {
// Say we're no longer downloading this
mDownloadsInProgress.remove(attachmentId);
// TODO: This code is conservative and treats connection issues as failures.
// Since we have no mechanism to throttle reconnection attempts, it makes
// sense to be cautious here. Once logic is in place to prevent connecting
// in a tight loop, we can exclude counting connection issues as "failures".
// Update the attachment failure list if needed
Integer downloadCount;
downloadCount = mAttachmentFailureMap.remove(attachmentId);
if (statusCode != EmailServiceStatus.SUCCESS) {
if (downloadCount == null) {
downloadCount = 0;
}
downloadCount += 1;
mAttachmentFailureMap.put(attachmentId, downloadCount);
}
final DownloadRequest req = mDownloadQueue.findRequestById(attachmentId);
if (statusCode == EmailServiceStatus.CONNECTION_ERROR) {
// If this needs to be retried, just process the queue again
if (req != null) {
req.mRetryCount++;
if (req.mRetryCount > CONNECTION_ERROR_MAX_RETRIES) {
// We are done, we maxed out our total number of tries.
LogUtils.d(LOG_TAG, "Connection Error #%d, giving up", attachmentId);
mDownloadQueue.removeRequest(req);
// Note that we are not doing anything with the attachment right now
// We will annotate it later in this function if needed.
} else if (req.mRetryCount > CONNECTION_ERROR_DELAY_THRESHOLD) {
// TODO: I'm not sure this is a great retry/backoff policy, but we're
// afraid of changing behavior too much in case something relies upon it.
// So now, for the first five errors, we'll retry immediately. For the next
// five tries, we'll add a ten second delay between each. After that, we'll
// give up.
LogUtils.d(LOG_TAG, "ConnectionError #%d, retried %d times, adding delay",
attachmentId, req.mRetryCount);
req.mInProgress = false;
req.mRetryStartTime = SystemClock.elapsedRealtime() +
CONNECTION_ERROR_RETRY_MILLIS;
mWatchdog.setWatchdogAlarm(mContext, CONNECTION_ERROR_RETRY_MILLIS,
CALLBACK_TIMEOUT);
} else {
LogUtils.d(LOG_TAG, "ConnectionError #%d, retried %d times, adding delay",
attachmentId, req.mRetryCount);
req.mInProgress = false;
req.mRetryStartTime = 0;
kick();
}
}
return;
}
// If the request is still in the queue, remove it
if (req != null) {
mDownloadQueue.removeRequest(req);
}
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
long secs = 0;
if (req != null) {
secs = (System.currentTimeMillis() - req.mTime) / 1000;
}
final String status = (statusCode == EmailServiceStatus.SUCCESS) ? "Success" :
"Error " + statusCode;
LogUtils.d(LOG_TAG, "<< Download finished for attachment #" + attachmentId + "; " + secs
+ " seconds from request, status: " + status);
}
final Attachment attachment = Attachment.restoreAttachmentWithId(mContext, attachmentId);
if (attachment != null) {
final long accountId = attachment.mAccountKey;
// Update our attachment storage for this account
Long currentStorage = mAttachmentStorageMap.get(accountId);
if (currentStorage == null) {
currentStorage = 0L;
}
mAttachmentStorageMap.put(accountId, currentStorage + attachment.mSize);
boolean deleted = false;
if ((attachment.mFlags & Attachment.FLAG_DOWNLOAD_FORWARD) != 0) {
if (statusCode == EmailServiceStatus.ATTACHMENT_NOT_FOUND) {
// If this is a forwarding download, and the attachment doesn't exist (or
// can't be downloaded) delete it from the outgoing message, lest that
// message never get sent
EmailContent.delete(mContext, Attachment.CONTENT_URI, attachment.mId);
// TODO: Talk to UX about whether this is even worth doing
NotificationController nc = NotificationController.getInstance(mContext);
nc.showDownloadForwardFailedNotification(attachment);
deleted = true;
}
// If we're an attachment on forwarded mail, and if we're not still blocked,
// try to send pending mail now (as mediated by MailService)
if ((req != null) &&
!Utility.hasUnloadedAttachments(mContext, attachment.mMessageKey)) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, "== Downloads finished for outgoing msg #"
+ req.mMessageId);
}
EmailServiceProxy service = EmailServiceUtils.getServiceForAccount(
mContext, accountId);
try {
service.sendMail(accountId);
} catch (RemoteException e) {
// We tried
}
}
}
if (statusCode == EmailServiceStatus.MESSAGE_NOT_FOUND) {
Message msg = Message.restoreMessageWithId(mContext, attachment.mMessageKey);
if (msg == null) {
// If there's no associated message, delete the attachment
EmailContent.delete(mContext, Attachment.CONTENT_URI, attachment.mId);
} else {
// If there really is a message, retry
// TODO: How will this get retried? It's still marked as inProgress?
kick();
return;
}
} else if (!deleted) {
// Clear the download flags, since we're done for now. Note that this happens
// only for non-recoverable errors. When these occur for forwarded mail, we can
// ignore it and continue; otherwise, it was either 1) a user request, in which
// case the user can retry manually or 2) an opportunistic download, in which
// case the download wasn't critical
ContentValues cv = new ContentValues();
int flags =
Attachment.FLAG_DOWNLOAD_FORWARD | Attachment.FLAG_DOWNLOAD_USER_REQUEST;
cv.put(AttachmentColumns.FLAGS, attachment.mFlags &= ~flags);
cv.put(AttachmentColumns.UI_STATE, AttachmentState.SAVED);
attachment.update(mContext, cv);
}
}
// Process the queue
kick();
}
/**
* Calculate the download priority of an Attachment. A priority of zero means that the
* attachment is not marked for download.
* @param att the Attachment
* @return the priority key of the Attachment
*/
private static int getPriority(final Attachment att) {
int priorityClass = PRIORITY_NONE;
final int flags = att.mFlags;
if ((flags & Attachment.FLAG_DOWNLOAD_FORWARD) != 0) {
priorityClass = PRIORITY_SEND_MAIL;
} else if ((flags & Attachment.FLAG_DOWNLOAD_USER_REQUEST) != 0) {
priorityClass = PRIORITY_FOREGROUND;
}
return priorityClass;
}
private void kick() {
synchronized(mLock) {
mLock.notify();
}
}
/**
* We use an EmailServiceCallback to keep track of the progress of downloads. These callbacks
* come from either Controller (IMAP) or ExchangeService (EAS). Note that we only implement the
* single callback that's defined by the EmailServiceCallback interface.
*/
class ServiceCallback extends IEmailServiceCallback.Stub {
@Override
public void loadAttachmentStatus(final long messageId, final long attachmentId,
final int statusCode, final int progress) {
// Record status and progress
final DownloadRequest req = mDownloadsInProgress.get(attachmentId);
if (req != null) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
final String code;
switch(statusCode) {
case EmailServiceStatus.SUCCESS: code = "Success"; break;
case EmailServiceStatus.IN_PROGRESS: code = "In progress"; break;
default: code = Integer.toString(statusCode); break;
}
if (statusCode != EmailServiceStatus.IN_PROGRESS) {
LogUtils.d(LOG_TAG, ">> Attachment status " + attachmentId + ": " + code);
} else if (progress >= (req.mLastProgress + 10)) {
LogUtils.d(LOG_TAG, ">> Attachment progress %d: %d%%", attachmentId, progress);
}
}
req.mLastStatusCode = statusCode;
req.mLastProgress = progress;
req.mLastCallbackTime = System.currentTimeMillis();
final Attachment attachment =
Attachment.restoreAttachmentWithId(mContext, attachmentId);
if (attachment != null && statusCode == EmailServiceStatus.IN_PROGRESS) {
final ContentValues values = new ContentValues();
values.put(AttachmentColumns.UI_DOWNLOADED_SIZE,
attachment.mSize * progress / 100);
// Update UIProvider with updated download size
// Individual services will set contentUri and state when finished
attachment.update(mContext, values);
}
switch (statusCode) {
case EmailServiceStatus.IN_PROGRESS:
break;
default:
endDownload(attachmentId, statusCode);
break;
}
} else {
// The only way that we can get a callback from the service implementation for
// an attachment that doesn't exist is if it was cancelled due to the
// AttachmentWatchdog. This is a valid scenario and the Watchdog should have already
// marked this attachment as failed/cancelled.
}
}
}
// The queue entries here are entries of the form {id, flags}, with the values passed in to
// attachmentChanged()
private static final Queue<long[]> sAttachmentChangedQueue =
new ConcurrentLinkedQueue<long[]>();
private static AsyncTask<Void, Void, Void> sAttachmentChangedTask;
/**
* Called directly by EmailProvider whenever an attachment is inserted or changed. Since this
* call is being invoked on the UI thread, we need to make sure that the downloads are
* happening in the background.
* @param context the caller's context
* @param id the attachment's id
* @param flags the new flags for the attachment
*/
public static void attachmentChanged(final Context context, final long id, final int flags) {
synchronized (sAttachmentChangedQueue) {
sAttachmentChangedQueue.add(new long[]{id, flags});
if (sAttachmentChangedTask == null) {
sAttachmentChangedTask = new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
while (true) {
final long[] change;
synchronized (sAttachmentChangedQueue) {
change = sAttachmentChangedQueue.poll();
if (change == null) {
sAttachmentChangedTask = null;
return null;
}
}
final long id = change[0];
final long flags = change[1];
final Attachment attachment =
Attachment.restoreAttachmentWithId(context, id);
if (attachment == null) {
continue;
}
attachment.mFlags = (int) flags;
final Intent intent =
new Intent(context, AttachmentService.class);
intent.putExtra(EXTRA_ATTACHMENT, attachment);
// This is result in a call to AttachmentService.onStartCommand()
// which will queue the attachment in its internal prioritized queue.
context.startService(intent);
}
}
}.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
}
}
}
/**
* Determine whether an attachment can be prefetched for the given account based on
* total download size restrictions tied to the account.
* @return true if download is allowed, false otherwise
*/
public boolean canPrefetchForAccount(final Account account, final File dir) {
// Check account, just in case
if (account == null) return false;
// First, check preference and quickly return if prefetch isn't allowed
if ((account.mFlags & Account.FLAGS_BACKGROUND_ATTACHMENTS) == 0) return false;
final long totalStorage = dir.getTotalSpace();
final long usableStorage = dir.getUsableSpace();
final long minAvailable = (long)(totalStorage * PREFETCH_MINIMUM_STORAGE_AVAILABLE);
// If there's not enough overall storage available, stop now
if (usableStorage < minAvailable) return false;
final int numberOfAccounts = mAccountManagerStub.getNumberOfAccounts();
// Calculate an even per-account storage although it would make a lot of sense to not
// do this as you may assign more storage to your corporate account rather than a personal
// account.
final long perAccountMaxStorage =
(long)(totalStorage * PREFETCH_MAXIMUM_ATTACHMENT_STORAGE / numberOfAccounts);
// Retrieve our idea of currently used attachment storage; since we don't track deletions,
// this number is the "worst case". If the number is greater than what's allowed per
// account, we walk the directory to determine the actual number.
Long accountStorage = mAttachmentStorageMap.get(account.mId);
if (accountStorage == null || (accountStorage > perAccountMaxStorage)) {
// Calculate the exact figure for attachment storage for this account
accountStorage = 0L;
File[] files = dir.listFiles();
if (files != null) {
for (File file : files) {
accountStorage += file.length();
}
}
// Cache the value. No locking here since this is a concurrent collection object.
mAttachmentStorageMap.put(account.mId, accountStorage);
}
// Return true if we're using less than the maximum per account
if (accountStorage >= perAccountMaxStorage) {
if (LogUtils.isLoggable(LOG_TAG, LogUtils.DEBUG)) {
LogUtils.d(LOG_TAG, ">> Prefetch not allowed for account " + account.mId +
"; used " + accountStorage + ", limit " + perAccountMaxStorage);
}
return false;
}
return true;
}
/**
* The main routine for our AttachmentService service thread.
*/
@Override
public void run() {
// These fields are only used within the service thread
mContext = this;
mConnectivityManager = new EmailConnectivityManager(this, LOG_TAG);
mAccountManagerStub = new AccountManagerStub(this);
// Run through all attachments in the database that require download and add them to
// the queue. This is the case where a previous AttachmentService may have been notified
// to stop before processing everything in its queue.
final int mask = Attachment.FLAG_DOWNLOAD_FORWARD | Attachment.FLAG_DOWNLOAD_USER_REQUEST;
final Cursor c = getContentResolver().query(Attachment.CONTENT_URI,
EmailContent.ID_PROJECTION, "(" + AttachmentColumns.FLAGS + " & ?) != 0",
new String[] {Integer.toString(mask)}, null);
try {
LogUtils.d(LOG_TAG, "Count: " + c.getCount());
while (c.moveToNext()) {
final Attachment attachment = Attachment.restoreAttachmentWithId(
this, c.getLong(EmailContent.ID_PROJECTION_COLUMN));
if (attachment != null) {
onChange(this, attachment);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
c.close();
}
// Loop until stopped, with a 30 minute wait loop
while (!mStop) {
// Here's where we run our attachment loading logic...
// Make a local copy of the variable so we don't null-crash on service shutdown
final EmailConnectivityManager ecm = mConnectivityManager;
if (ecm != null) {
ecm.waitForConnectivity();
}
if (mStop) {
// We might be bailing out here due to the service shutting down
LogUtils.d(LOG_TAG, "*** AttachmentService has been instructed to stop");
break;
}
processQueue();
if (mDownloadQueue.isEmpty()) {
LogUtils.d(LOG_TAG, "*** All done; shutting down service");
stopSelf();
break;
}
synchronized(mLock) {
try {
mLock.wait(PROCESS_QUEUE_WAIT_TIME);
} catch (InterruptedException e) {
// That's ok; we'll just keep looping
}
}
}
// Unregister now that we're done
// Make a local copy of the variable so we don't null-crash on service shutdown
final EmailConnectivityManager ecm = mConnectivityManager;
if (ecm != null) {
ecm.unregister();
}
}
@Override
public int onStartCommand(final Intent intent, final int flags, final int startId) {
if (sRunningService == null) {
sRunningService = this;
}
if (intent != null && intent.hasExtra(EXTRA_ATTACHMENT)) {
Attachment att = intent.getParcelableExtra(EXTRA_ATTACHMENT);
onChange(mContext, att);
} else {
LogUtils.wtf(LOG_TAG, "Received an invalid intent w/o EXTRA_ATTACHMENT");
}
return Service.START_STICKY;
}
@Override
public void onCreate() {
// Start up our service thread.
new Thread(this, "AttachmentService").start();
}
@Override
public IBinder onBind(final Intent intent) {
return null;
}
@Override
public void onDestroy() {
// Mark this instance of the service as stopped. Our main loop for the AttachmentService
// checks for this flag along with the AttachmentWatchdog.
mStop = true;
if (sRunningService != null) {
// Kick it awake to get it to realize that we are stopping.
kick();
sRunningService = null;
}
if (mConnectivityManager != null) {
mConnectivityManager.unregister();
mConnectivityManager.stopWait();
mConnectivityManager = null;
}
}
// For Debugging.
@Override
public void dump(final FileDescriptor fd, final PrintWriter pw, final String[] args) {
pw.println("AttachmentService");
final long time = System.currentTimeMillis();
synchronized(mDownloadQueue) {
pw.println(" Queue, " + mDownloadQueue.getSize() + " entries");
// If you iterate over the queue either via iterator or collection, they are not
// returned in any particular order. With all things being equal its better to go with
// a collection to avoid any potential ConcurrentModificationExceptions.
// If we really want this sorted, we can sort it manually since performance isn't a big
// concern with this debug method.
for (final DownloadRequest req : mDownloadQueue.mRequestMap.values()) {
pw.println(" Account: " + req.mAccountId + ", Attachment: " + req.mAttachmentId);
pw.println(" Priority: " + req.mPriority + ", Time: " + req.mTime +
(req.mInProgress ? " [In progress]" : ""));
final Attachment att = Attachment.restoreAttachmentWithId(this, req.mAttachmentId);
if (att == null) {
pw.println(" Attachment not in database?");
} else if (att.mFileName != null) {
final String fileName = att.mFileName;
final String suffix;
final int lastDot = fileName.lastIndexOf('.');
if (lastDot >= 0) {
suffix = fileName.substring(lastDot);
} else {
suffix = "[none]";
}
pw.print(" Suffix: " + suffix);
if (att.getContentUri() != null) {
pw.print(" ContentUri: " + att.getContentUri());
}
pw.print(" Mime: ");
if (att.mMimeType != null) {
pw.print(att.mMimeType);
} else {
pw.print(AttachmentUtilities.inferMimeType(fileName, null));
pw.print(" [inferred]");
}
pw.println(" Size: " + att.mSize);
}
if (req.mInProgress) {
pw.println(" Status: " + req.mLastStatusCode + ", Progress: " +
req.mLastProgress);
pw.println(" Started: " + req.mStartTime + ", Callback: " +
req.mLastCallbackTime);
pw.println(" Elapsed: " + ((time - req.mStartTime) / 1000L) + "s");
if (req.mLastCallbackTime > 0) {
pw.println(" CB: " + ((time - req.mLastCallbackTime) / 1000L) + "s");
}
}
}
}
}
// For Testing
AccountManagerStub mAccountManagerStub;
private final HashMap<Long, Intent> mAccountServiceMap = new HashMap<Long, Intent>();
void addServiceIntentForTest(final long accountId, final Intent intent) {
mAccountServiceMap.put(accountId, intent);
}
/**
* We only use the getAccounts() call from AccountManager, so this class wraps that call and
* allows us to build a mock account manager stub in the unit tests
*/
static class AccountManagerStub {
private int mNumberOfAccounts;
private final AccountManager mAccountManager;
AccountManagerStub(final Context context) {
if (context != null) {
mAccountManager = AccountManager.get(context);
} else {
mAccountManager = null;
}
}
int getNumberOfAccounts() {
if (mAccountManager != null) {
return mAccountManager.getAccounts().length;
} else {
return mNumberOfAccounts;
}
}
void setNumberOfAccounts(final int numberOfAccounts) {
mNumberOfAccounts = numberOfAccounts;
}
}
}