session-ios/SignalServiceKit/src/Messages/OWSDisappearingMessagesJob.m

421 lines
15 KiB
Objective-C

//
// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
//
#import "OWSDisappearingMessagesJob.h"
#import "AppContext.h"
#import "AppReadiness.h"
#import "ContactsManagerProtocol.h"
#import "NSTimer+OWS.h"
#import "OWSBackgroundTask.h"
#import "OWSDisappearingConfigurationUpdateInfoMessage.h"
#import "OWSDisappearingMessagesConfiguration.h"
#import "OWSDisappearingMessagesFinder.h"
#import "OWSPrimaryStorage.h"
#import "SSKEnvironment.h"
#import "TSIncomingMessage.h"
#import "TSMessage.h"
#import "TSThread.h"
#import <SignalCoreKit/NSDate+OWS.h>
NS_ASSUME_NONNULL_BEGIN
// Can we move to Signal-iOS?
@interface OWSDisappearingMessagesJob ()
@property (nonatomic, readonly) YapDatabaseConnection *databaseConnection;
@property (nonatomic, readonly) OWSDisappearingMessagesFinder *disappearingMessagesFinder;
+ (dispatch_queue_t)serialQueue;
// These three properties should only be accessed on the main thread.
@property (nonatomic) BOOL hasStarted;
@property (nonatomic, nullable) NSTimer *nextDisappearanceTimer;
@property (nonatomic, nullable) NSDate *nextDisappearanceDate;
@property (nonatomic, nullable) NSTimer *fallbackTimer;
@end
void AssertIsOnDisappearingMessagesQueue()
{
#ifdef DEBUG
if (@available(iOS 10.0, *)) {
dispatch_assert_queue(OWSDisappearingMessagesJob.serialQueue);
}
#endif
}
#pragma mark -
@implementation OWSDisappearingMessagesJob
+ (instancetype)sharedJob
{
OWSAssertDebug(SSKEnvironment.shared.disappearingMessagesJob);
return SSKEnvironment.shared.disappearingMessagesJob;
}
- (instancetype)initWithPrimaryStorage:(OWSPrimaryStorage *)primaryStorage
{
self = [super init];
if (!self) {
return self;
}
_databaseConnection = primaryStorage.newDatabaseConnection;
_disappearingMessagesFinder = [OWSDisappearingMessagesFinder new];
// suspenders in case a deletion schedule is missed.
NSTimeInterval kFallBackTimerInterval = 5 * kMinuteInterval;
[AppReadiness runNowOrWhenAppDidBecomeReady:^{
if (CurrentAppContext().isMainApp) {
self.fallbackTimer = [NSTimer weakScheduledTimerWithTimeInterval:kFallBackTimerInterval
target:self
selector:@selector(fallbackTimerDidFire)
userInfo:nil
repeats:YES];
}
}];
OWSSingletonAssert();
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationDidBecomeActive:)
name:OWSApplicationDidBecomeActiveNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationWillResignActive:)
name:OWSApplicationWillResignActiveNotification
object:nil];
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
+ (dispatch_queue_t)serialQueue
{
static dispatch_queue_t queue = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
queue = dispatch_queue_create("org.whispersystems.disappearing.messages", DISPATCH_QUEUE_SERIAL);
});
return queue;
}
#pragma mark - Dependencies
- (id<ContactsManagerProtocol>)contactsManager
{
return SSKEnvironment.shared.contactsManager;
}
#pragma mark -
- (NSUInteger)deleteExpiredMessages
{
AssertIsOnDisappearingMessagesQueue();
uint64_t now = [NSDate ows_millisecondTimeStamp];
OWSBackgroundTask *_Nullable backgroundTask = [OWSBackgroundTask backgroundTaskWithLabelStr:__PRETTY_FUNCTION__];
__block NSUInteger expirationCount = 0;
[self.databaseConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
[self.disappearingMessagesFinder enumerateExpiredMessagesWithBlock:^(TSMessage *message) {
// sanity check
if (message.expiresAt > now) {
OWSFailDebug(@"Refusing to remove message which doesn't expire until: %lld", message.expiresAt);
return;
}
OWSLogInfo(@"Removing message which expired at: %lld", message.expiresAt);
[message removeWithTransaction:transaction];
expirationCount++;
}
transaction:transaction];
}];
OWSLogDebug(@"Removed %lu expired messages", (unsigned long)expirationCount);
OWSAssertDebug(backgroundTask);
backgroundTask = nil;
return expirationCount;
}
// deletes any expired messages and schedules the next run.
- (NSUInteger)runLoop
{
OWSLogVerbose(@"in runLoop");
AssertIsOnDisappearingMessagesQueue();
NSUInteger deletedCount = [self deleteExpiredMessages];
__block NSNumber *nextExpirationTimestampNumber;
[self.databaseConnection readWithBlock:^(YapDatabaseReadTransaction *_Nonnull transaction) {
nextExpirationTimestampNumber =
[self.disappearingMessagesFinder nextExpirationTimestampWithTransaction:transaction];
}];
if (!nextExpirationTimestampNumber) {
OWSLogDebug(@"No more expiring messages.");
return deletedCount;
}
uint64_t nextExpirationAt = nextExpirationTimestampNumber.unsignedLongLongValue;
NSDate *nextEpirationDate = [NSDate ows_dateWithMillisecondsSince1970:nextExpirationAt];
[self scheduleRunByDate:nextEpirationDate];
return deletedCount;
}
- (void)startAnyExpirationForMessage:(TSMessage *)message
expirationStartedAt:(uint64_t)expirationStartedAt
transaction:(YapDatabaseReadWriteTransaction *_Nonnull)transaction
{
OWSAssertDebug(transaction);
if (!message.isExpiringMessage) {
return;
}
NSTimeInterval startedSecondsAgo = ([NSDate ows_millisecondTimeStamp] - expirationStartedAt) / 1000.0;
OWSLogDebug(@"Starting expiration for message read %f seconds ago", startedSecondsAgo);
// Don't clobber if multiple actions simultaneously triggered expiration.
if (message.expireStartedAt == 0 || message.expireStartedAt > expirationStartedAt) {
[message updateWithExpireStartedAt:expirationStartedAt transaction:transaction];
}
[transaction addCompletionQueue:nil
completionBlock:^{
// Necessary that the async expiration run happens *after* the message is saved with it's new
// expiration configuration.
[self scheduleRunByDate:[NSDate ows_dateWithMillisecondsSince1970:message.expiresAt]];
}];
}
#pragma mark - Apply Remote Configuration
- (void)becomeConsistentWithDisappearingDuration:(uint32_t)duration
thread:(TSThread *)thread
createdByRemoteRecipientId:(nullable NSString *)remoteRecipientId
createdInExistingGroup:(BOOL)createdInExistingGroup
transaction:(YapDatabaseReadWriteTransaction *)transaction
{
OWSAssertDebug(thread);
OWSAssertDebug(transaction);
OWSBackgroundTask *_Nullable backgroundTask = [OWSBackgroundTask backgroundTaskWithLabelStr:__PRETTY_FUNCTION__];
NSString *_Nullable remoteContactName = nil;
if (remoteRecipientId) {
remoteContactName = [self.contactsManager displayNameForPhoneIdentifier:remoteRecipientId
transaction:transaction];
}
// Become eventually consistent in the case that the remote changed their settings at the same time.
// Also in case remote doesn't support expiring messages
OWSDisappearingMessagesConfiguration *disappearingMessagesConfiguration =
[thread disappearingMessagesConfigurationWithTransaction:transaction];
if (duration == 0) {
disappearingMessagesConfiguration.enabled = NO;
} else {
disappearingMessagesConfiguration.enabled = YES;
disappearingMessagesConfiguration.durationSeconds = duration;
}
if (!disappearingMessagesConfiguration.dictionaryValueDidChange) {
return;
}
OWSLogInfo(@"becoming consistent with disappearing message configuration: %@",
disappearingMessagesConfiguration.dictionaryValue);
[disappearingMessagesConfiguration saveWithTransaction:transaction];
// MJK TODO - should be safe to remove this senderTimestamp
OWSDisappearingConfigurationUpdateInfoMessage *infoMessage =
[[OWSDisappearingConfigurationUpdateInfoMessage alloc] initWithTimestamp:[NSDate ows_millisecondTimeStamp]
thread:thread
configuration:disappearingMessagesConfiguration
createdByRemoteName:remoteContactName
createdInExistingGroup:createdInExistingGroup];
[infoMessage saveWithTransaction:transaction];
OWSAssertDebug(backgroundTask);
backgroundTask = nil;
}
#pragma mark -
- (void)startIfNecessary
{
dispatch_async(dispatch_get_main_queue(), ^{
if (self.hasStarted) {
return;
}
self.hasStarted = YES;
dispatch_async(OWSDisappearingMessagesJob.serialQueue, ^{
// Theoretically this shouldn't be necessary, but there was a race condition when receiving a backlog
// of messages across timer changes which could cause a disappearing message's timer to never be started.
[self.databaseConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
[self cleanupMessagesWhichFailedToStartExpiringWithTransaction:transaction];
}];
[self runLoop];
});
});
}
- (NSDateFormatter *)dateFormatter
{
static NSDateFormatter *dateFormatter;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
dateFormatter = [NSDateFormatter new];
dateFormatter.dateStyle = NSDateFormatterNoStyle;
dateFormatter.timeStyle = kCFDateFormatterMediumStyle;
dateFormatter.locale = [NSLocale systemLocale];
});
return dateFormatter;
}
- (void)scheduleRunByDate:(NSDate *)date
{
OWSAssertDebug(date);
dispatch_async(dispatch_get_main_queue(), ^{
if (!CurrentAppContext().isMainAppAndActive) {
// Don't schedule run when inactive or not in main app.
return;
}
// Don't run more often than once per second.
const NSTimeInterval kMinDelaySeconds = 1.0;
NSTimeInterval delaySeconds = MAX(kMinDelaySeconds, date.timeIntervalSinceNow);
NSDate *newTimerScheduleDate = [NSDate dateWithTimeIntervalSinceNow:delaySeconds];
if (self.nextDisappearanceDate && [self.nextDisappearanceDate isBeforeDate:newTimerScheduleDate]) {
OWSLogVerbose(@"Request to run at %@ (%d sec.) ignored due to earlier scheduled run at %@ (%d sec.)",
[self.dateFormatter stringFromDate:date],
(int)round(MAX(0, [date timeIntervalSinceDate:[NSDate new]])),
[self.dateFormatter stringFromDate:self.nextDisappearanceDate],
(int)round(MAX(0, [self.nextDisappearanceDate timeIntervalSinceDate:[NSDate new]])));
return;
}
// Update Schedule
OWSLogVerbose(@"Scheduled run at %@ (%d sec.)",
[self.dateFormatter stringFromDate:newTimerScheduleDate],
(int)round(MAX(0, [newTimerScheduleDate timeIntervalSinceDate:[NSDate new]])));
[self resetNextDisappearanceTimer];
self.nextDisappearanceDate = newTimerScheduleDate;
self.nextDisappearanceTimer = [NSTimer weakScheduledTimerWithTimeInterval:delaySeconds
target:self
selector:@selector(disappearanceTimerDidFire)
userInfo:nil
repeats:NO];
});
}
- (void)disappearanceTimerDidFire
{
OWSAssertIsOnMainThread();
OWSLogDebug(@"");
if (!CurrentAppContext().isMainAppAndActive) {
// Don't schedule run when inactive or not in main app.
OWSFailDebug(@"Disappearing messages job timer fired while main app inactive.");
return;
}
[self resetNextDisappearanceTimer];
dispatch_async(OWSDisappearingMessagesJob.serialQueue, ^{
[self runLoop];
});
}
- (void)fallbackTimerDidFire
{
OWSAssertIsOnMainThread();
OWSLogDebug(@"");
BOOL recentlyScheduledDisappearanceTimer = NO;
if (fabs(self.nextDisappearanceDate.timeIntervalSinceNow) < 1.0) {
recentlyScheduledDisappearanceTimer = YES;
}
if (!CurrentAppContext().isMainAppAndActive) {
OWSLogInfo(@"Ignoring fallbacktimer for app which is not main and active.");
return;
}
dispatch_async(OWSDisappearingMessagesJob.serialQueue, ^{
NSUInteger deletedCount = [self runLoop];
// Normally deletions should happen via the disappearanceTimer, to make sure that they're prompt.
// So, if we're deleting something via this fallback timer, something may have gone wrong. The
// exception is if we're in close proximity to the disappearanceTimer, in which case a race condition
// is inevitable.
if (!recentlyScheduledDisappearanceTimer && deletedCount > 0) {
OWSFailDebug(@"unexpectedly deleted disappearing messages via fallback timer.");
}
});
}
- (void)resetNextDisappearanceTimer
{
OWSAssertIsOnMainThread();
[self.nextDisappearanceTimer invalidate];
self.nextDisappearanceTimer = nil;
self.nextDisappearanceDate = nil;
}
#pragma mark - Cleanup
- (void)cleanupMessagesWhichFailedToStartExpiringWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
{
[self.disappearingMessagesFinder
enumerateMessagesWhichFailedToStartExpiringWithBlock:^(TSMessage *_Nonnull message) {
OWSFailDebug(@"starting old timer for message timestamp: %lu", (unsigned long)message.timestamp);
// We don't know when it was actually read, so assume it was read as soon as it was received.
uint64_t readTimeBestGuess = message.receivedAtTimestamp;
[self startAnyExpirationForMessage:message expirationStartedAt:readTimeBestGuess transaction:transaction];
}
transaction:transaction];
}
#pragma mark - Notifications
- (void)applicationDidBecomeActive:(NSNotification *)notification
{
OWSAssertIsOnMainThread();
[AppReadiness runNowOrWhenAppDidBecomeReady:^{
dispatch_async(OWSDisappearingMessagesJob.serialQueue, ^{
[self runLoop];
});
}];
}
- (void)applicationWillResignActive:(NSNotification *)notification
{
OWSAssertIsOnMainThread();
[self resetNextDisappearanceTimer];
}
@end
NS_ASSUME_NONNULL_END