pop view if message is deleted

- use global ui database connection

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -123,6 +123,7 @@ typedef enum : NSUInteger {
     ConversationViewCellDelegate,
     ConversationInputTextViewDelegate,
     MessageActionsDelegate,
+    MessageDetailViewDelegate,
     MenuActionsViewControllerDelegate,
     OWSMessageBubbleViewDelegate,
     UICollectionViewDelegate,
@@ -1924,6 +1925,14 @@ typedef enum : NSUInteger {
     [self populateReplyForViewItem:conversationViewItem];
 }
 
+#pragma mark - MessageDetailViewDelegate
+
+- (void)detailViewMessageWasDeleted:(MessageDetailViewController *)messageDetailViewController
+{
+    OWSLogInfo(@"");
+    [self.navigationController popToViewController:self animated:YES];
+}
+
 #pragma mark - MenuActionsViewControllerDelegate
 
 - (void)menuActionsDidHide:(MenuActionsViewController *)menuActionsViewController
@@ -2158,7 +2167,6 @@ typedef enum : NSUInteger {
 
     MediaGallery *mediaGallery =
         [[MediaGallery alloc] initWithThread:self.thread
-                        uiDatabaseConnection:self.uiDatabaseConnection
                                      options:MediaGalleryOptionSliderEnabled | MediaGalleryOptionShowAllMediaButton];
 
     [mediaGallery presentDetailViewFromViewController:self mediaAttachment:attachmentStream replacingView:imageView];
@@ -2181,7 +2189,6 @@ typedef enum : NSUInteger {
 
     MediaGallery *mediaGallery =
         [[MediaGallery alloc] initWithThread:self.thread
-                        uiDatabaseConnection:self.uiDatabaseConnection
                                      options:MediaGalleryOptionSliderEnabled | MediaGalleryOptionShowAllMediaButton];
 
     [mediaGallery presentDetailViewFromViewController:self mediaAttachment:attachmentStream replacingView:imageView];
@@ -2358,12 +2365,13 @@ typedef enum : NSUInteger {
     OWSAssertDebug([conversationItem.interaction isKindOfClass:[TSMessage class]]);
 
     TSMessage *message = (TSMessage *)conversationItem.interaction;
-    MessageDetailViewController *view =
+    MessageDetailViewController *detailVC =
         [[MessageDetailViewController alloc] initWithViewItem:conversationItem
                                                       message:message
                                                        thread:self.thread
                                                          mode:MessageMetadataViewModeFocusOnMetadata];
-    [self.navigationController pushViewController:view animated:YES];
+    detailVC.delegate = self;
+    [self.navigationController pushViewController:detailVC animated:YES];
 }
 
 - (void)populateReplyForViewItem:(id<ConversationViewItem>)conversationItem

Signal/src/ViewControllers/HomeView/ConversationSearchViewController.swift

@@ -73,8 +73,8 @@ class ConversationSearchViewController: UITableViewController, BlockListCacheDel
         tableView.register(ContactTableViewCell.self, forCellReuseIdentifier: ContactTableViewCell.reuseIdentifier())
 
         NotificationCenter.default.addObserver(self,
-                                               selector: #selector(yapDatabaseModified),
+                                               selector: #selector(uiDatabaseModified),
-                                               name: NSNotification.Name.YapDatabaseModified,
+                                               name: .OWSUIDatabaseConnectionDidUpdate,
                                                object: OWSPrimaryStorage.shared().dbNotificationObject)
         NotificationCenter.default.addObserver(self,
                                                selector: #selector(themeDidChange),
@@ -101,7 +101,7 @@ class ConversationSearchViewController: UITableViewController, BlockListCacheDel
         NotificationCenter.default.removeObserver(self)
     }
 
-    @objc internal func yapDatabaseModified(notification: NSNotification) {
+    @objc internal func uiDatabaseModified(notification: NSNotification) {
         AssertIsOnMainThread()
 
         refreshSearchResults()

Signal/src/ViewControllers/MediaGalleryViewController.swift

@@ -229,11 +229,11 @@ protocol MediaGalleryDataSource: class {
     func showAllMedia(focusedItem: MediaGalleryItem)
     func dismissMediaDetailViewController(_ mediaDetailViewController: MediaPageViewController, animated isAnimated: Bool, completion: (() -> Void)?)
 
-    func delete(items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate)
+    func delete(items: [MediaGalleryItem], initiatedBy: AnyObject)
 }
 
 protocol MediaGalleryDataSourceDelegate: class {
-    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate)
+    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject)
     func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, deletedSections: IndexSet, deletedItems: [IndexPath])
 }
 
@@ -318,7 +318,10 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
 
     private var pageViewController: MediaPageViewController?
 
-    private let uiDatabaseConnection: YapDatabaseConnection
+    private var uiDatabaseConnection: YapDatabaseConnection {
+        return OWSPrimaryStorage.shared().uiDatabaseConnection
+    }
+
     private let editingDatabaseConnection: YapDatabaseConnection
     private let mediaGalleryFinder: OWSMediaGalleryFinder
 
@@ -334,16 +337,19 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
     }
 
     @objc
-    init(thread: TSThread, uiDatabaseConnection: YapDatabaseConnection, options: MediaGalleryOption = []) {
+    init(thread: TSThread, options: MediaGalleryOption = []) {
         self.thread = thread
-        assert(uiDatabaseConnection.isInLongLivedReadTransaction())
-        self.uiDatabaseConnection = uiDatabaseConnection
 
         self.editingDatabaseConnection = OWSPrimaryStorage.shared().newDatabaseConnection()
 
         self.options = options
         self.mediaGalleryFinder = OWSMediaGalleryFinder(thread: thread)
         super.init()
+
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(uiDatabaseDidUpdate),
+                                               name: .OWSUIDatabaseConnectionDidUpdate,
+                                               object: OWSPrimaryStorage.shared().dbNotificationObject)
     }
 
     // MARK: Present/Dismiss
@@ -709,7 +715,70 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
         ]
     }
 
-    // MARK: MediaGalleryDataSource
+    // MARK: - Database Notifications
+
+    @objc
+    func uiDatabaseDidUpdate(notification: Notification) {
+        guard let notifications = notification.userInfo?[OWSUIDatabaseConnectionNotificationsKey] as? [Notification] else {
+            owsFailDebug("notifications was unexpectedly nil")
+            return
+        }
+
+        guard mediaGalleryFinder.hasMediaChanges(in: notifications, dbConnection: uiDatabaseConnection) else {
+            Logger.verbose("no changes for thread: \(thread)")
+            return
+        }
+
+        let rowChanges = extractRowChanges(notifications: notifications)
+        assert(rowChanges.count > 0)
+
+        process(rowChanges: rowChanges)
+    }
+
+    func extractRowChanges(notifications: [Notification]) -> [YapDatabaseViewRowChange] {
+        return notifications.flatMap { notification -> [YapDatabaseViewRowChange] in
+            guard let userInfo = notification.userInfo else {
+                owsFailDebug("userInfo was unexpectedly nil")
+                return []
+            }
+
+            guard let extensionChanges = userInfo["extensions"] as? [AnyHashable: Any] else {
+                owsFailDebug("extensionChanges was unexpectedly nil")
+                return []
+            }
+
+            guard let galleryData = extensionChanges[OWSMediaGalleryFinder.databaseExtensionName()] as? [AnyHashable: Any] else {
+                owsFailDebug("galleryData was unexpectedly nil")
+                return []
+            }
+
+            guard let galleryChanges = galleryData["changes"] as? [Any] else {
+                owsFailDebug("gallerlyChanges was unexpectedly nil")
+                return []
+            }
+
+            return galleryChanges.compactMap { $0 as? YapDatabaseViewRowChange }
+        }
+    }
+
+    func process(rowChanges: [YapDatabaseViewRowChange]) {
+        let deleteChanges = rowChanges.filter { $0.type == .delete }
+
+        let deletedItems: [MediaGalleryItem] = deleteChanges.compactMap { (deleteChange: YapDatabaseViewRowChange) -> MediaGalleryItem? in
+            guard let deletedItem = self.galleryItems.first(where: { galleryItem in
+                galleryItem.attachmentStream.uniqueId == deleteChange.collectionKey.key
+            }) else {
+                Logger.debug("deletedItem was never loaded - no need to remove.")
+                return nil
+            }
+
+            return deletedItem
+        }
+
+        self.delete(items: deletedItems, initiatedBy: self)
+    }
+
+    // MARK: - MediaGalleryDataSource
 
     lazy var mediaTileViewController: MediaTileViewController = {
         let vc = MediaTileViewController(mediaGalleryDataSource: self, uiDatabaseConnection: self.uiDatabaseConnection)
@@ -777,6 +846,10 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
         }
     }
 
+    enum MediaGalleryError: Error {
+        case itemNoLongerExists
+    }
+
     func ensureGalleryItemsLoaded(_ direction: GalleryDirection, item: MediaGalleryItem, amount: UInt, completion: ((IndexSet, [IndexPath]) -> Void)? = nil ) {
 
         var galleryItems: [MediaGalleryItem] = self.galleryItems
@@ -786,92 +859,102 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
         var newGalleryItems: [MediaGalleryItem] = []
         var newDates: [GalleryDate] = []
 
-        Bench(title: "fetching gallery items") {
+        do {
-            self.uiDatabaseConnection.read { transaction in
+            try Bench(title: "fetching gallery items") {
-
+                try self.uiDatabaseConnection.read { transaction in
-                let initialIndex: Int = Int(self.mediaGalleryFinder.mediaIndex(attachment: item.attachmentStream, transaction: transaction))
+                    guard let index = self.mediaGalleryFinder.mediaIndex(attachment: item.attachmentStream, transaction: transaction) else {
-                let mediaCount: Int = Int(self.mediaGalleryFinder.mediaCount(transaction: transaction))
+                        throw MediaGalleryError.itemNoLongerExists
-
+                    }
-                let requestRange: Range<Int> = { () -> Range<Int> in
+                    let initialIndex: Int = index.intValue
-                    let range: Range<Int> = { () -> Range<Int> in
+                    let mediaCount: Int = Int(self.mediaGalleryFinder.mediaCount(transaction: transaction))
-                        switch direction {
+
-                        case .around:
+                    let requestRange: Range<Int> = { () -> Range<Int> in
-                            // To keep it simple, this isn't exactly *amount* sized if `message` window overlaps the end or
+                        let range: Range<Int> = { () -> Range<Int> in
-                            // beginning of the view. Still, we have sufficient buffer to fetch more as the user swipes.
+                            switch direction {
-                            let start: Int = initialIndex - Int(amount) / 2
+                            case .around:
-                            let end: Int = initialIndex + Int(amount) / 2
+                                // To keep it simple, this isn't exactly *amount* sized if `message` window overlaps the end or
-
+                                // beginning of the view. Still, we have sufficient buffer to fetch more as the user swipes.
-                            return start..<end
+                                let start: Int = initialIndex - Int(amount) / 2
-                        case .before:
+                                let end: Int = initialIndex + Int(amount) / 2
-                            let start: Int = initialIndex - Int(amount)
+
-                            let end: Int = initialIndex
+                                return start..<end
-
+                            case .before:
-                            return start..<end
+                                let start: Int = initialIndex - Int(amount)
-                        case  .after:
+                                let end: Int = initialIndex
-                            let start: Int = initialIndex
+
-                            let end: Int = initialIndex  + Int(amount)
+                                return start..<end
+                            case  .after:
+                                let start: Int = initialIndex
+                                let end: Int = initialIndex  + Int(amount)
+
+                                return start..<end
+                            }
+                        }()
 
-                            return start..<end
+                        return range.clamped(to: 0..<mediaCount)
-                        }
                     }()
 
-                    return range.clamped(to: 0..<mediaCount)
+                    let requestSet = IndexSet(integersIn: requestRange)
-                }()
+                    guard !self.fetchedIndexSet.contains(integersIn: requestSet) else {
-
+                        Logger.debug("all requested messages have already been loaded.")
-                let requestSet = IndexSet(integersIn: requestRange)
+                        return
-                guard !self.fetchedIndexSet.contains(integersIn: requestSet) else {
+                    }
-                    Logger.debug("all requested messages have already been loaded.")
-                    return
-                }
-
-                let unfetchedSet = requestSet.subtracting(self.fetchedIndexSet)
-
-                // For perf we only want to fetch a substantially full batch...
-                let isSubstantialRequest = unfetchedSet.count > (requestSet.count / 2)
-                // ...but we always fulfill even small requests if we're getting just the tail end of a gallery.
-                let isFetchingEdgeOfGallery = (self.fetchedIndexSet.count - unfetchedSet.count) < requestSet.count
 
-                guard isSubstantialRequest || isFetchingEdgeOfGallery else {
+                    let unfetchedSet = requestSet.subtracting(self.fetchedIndexSet)
-                    Logger.debug("ignoring small fetch request: \(unfetchedSet.count)")
-                    return
-                }
 
-                Logger.debug("fetching set: \(unfetchedSet)")
+                    // For perf we only want to fetch a substantially full batch...
-                let nsRange: NSRange = NSRange(location: unfetchedSet.min()!, length: unfetchedSet.count)
+                    let isSubstantialRequest = unfetchedSet.count > (requestSet.count / 2)
-                self.mediaGalleryFinder.enumerateMediaAttachments(range: nsRange, transaction: transaction) { (attachment: TSAttachment) in
+                    // ...but we always fulfill even small requests if we're getting just the tail end of a gallery.
+                    let isFetchingEdgeOfGallery = (self.fetchedIndexSet.count - unfetchedSet.count) < requestSet.count
 
-                    guard !self.deletedAttachments.contains(attachment) else {
+                    guard isSubstantialRequest || isFetchingEdgeOfGallery else {
-                        Logger.debug("skipping \(attachment) which has been deleted.")
+                        Logger.debug("ignoring small fetch request: \(unfetchedSet.count)")
                         return
                     }
 
-                    guard let item: MediaGalleryItem = self.buildGalleryItem(attachment: attachment, transaction: transaction) else {
+                    Logger.debug("fetching set: \(unfetchedSet)")
-                        owsFailDebug("unexpectedly failed to buildGalleryItem")
+                    let nsRange: NSRange = NSRange(location: unfetchedSet.min()!, length: unfetchedSet.count)
-                        return
+                    self.mediaGalleryFinder.enumerateMediaAttachments(range: nsRange, transaction: transaction) { (attachment: TSAttachment) in
-                    }
 
-                    let date = item.galleryDate
+                        guard !self.deletedAttachments.contains(attachment) else {
+                            Logger.debug("skipping \(attachment) which has been deleted.")
+                            return
+                        }
 
-                    galleryItems.append(item)
+                        guard let item: MediaGalleryItem = self.buildGalleryItem(attachment: attachment, transaction: transaction) else {
-                    if sections[date] != nil {
+                            owsFailDebug("unexpectedly failed to buildGalleryItem")
-                        sections[date]!.append(item)
+                            return
+                        }
 
-                        // so we can update collectionView
+                        let date = item.galleryDate
-                        newGalleryItems.append(item)
-                    } else {
-                        sectionDates.append(date)
-                        sections[date] = [item]
 
-                        // so we can update collectionView
+                        galleryItems.append(item)
-                        newDates.append(date)
+                        if sections[date] != nil {
-                        newGalleryItems.append(item)
+                            sections[date]!.append(item)
+
+                            // so we can update collectionView
+                            newGalleryItems.append(item)
+                        } else {
+                            sectionDates.append(date)
+                            sections[date] = [item]
+
+                            // so we can update collectionView
+                            newDates.append(date)
+                            newGalleryItems.append(item)
+                        }
                     }
-                }
 
-                self.fetchedIndexSet = self.fetchedIndexSet.union(unfetchedSet)
+                    self.fetchedIndexSet = self.fetchedIndexSet.union(unfetchedSet)
-                self.hasFetchedOldest = self.fetchedIndexSet.min() == 0
+                    self.hasFetchedOldest = self.fetchedIndexSet.min() == 0
-                self.hasFetchedMostRecent = self.fetchedIndexSet.max() == mediaCount - 1
+                    self.hasFetchedMostRecent = self.fetchedIndexSet.max() == mediaCount - 1
+                }
             }
+        } catch MediaGalleryError.itemNoLongerExists {
+            Logger.debug("Ignoring reload, since item no longer exists.")
+            return
+        } catch {
+            owsFailDebug("unexpected error: \(error)")
+            return
         }
 
         // TODO only sort if changed
@@ -919,7 +1002,7 @@ class MediaGallery: NSObject, MediaGalleryDataSource, MediaTileViewControllerDel
         dataSourceDelegates.append(Weak(value: dataSourceDelegate))
     }
 
-    func delete(items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate) {
+    func delete(items: [MediaGalleryItem], initiatedBy: AnyObject) {
         AssertIsOnMainThread()
 
         Logger.info("with items: \(items.map { ($0.attachmentStream, $0.message.timestamp) })")

Signal/src/ViewControllers/MediaPageViewController.swift

@@ -401,11 +401,11 @@ class MediaPageViewController: UIPageViewController, UIPageViewControllerDataSou
 
     // MARK: MediaGalleryDataSourceDelegate
 
-    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate) {
+    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject) {
         Logger.debug("")
 
         guard let currentItem = self.currentItem else {
-              owsFailDebug("currentItem was unexpectedly nil")
+            owsFailDebug("currentItem was unexpectedly nil")
             return
         }
 

Signal/src/ViewControllers/MediaTileViewController.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -610,7 +610,7 @@ public class MediaTileViewController: UICollectionViewController, MediaGalleryDa
 
     // MARK: MediaGalleryDataSourceDelegate
 
-    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate) {
+    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject) {
         Logger.debug("")
 
         guard let collectionView = self.collectionView else {

Signal/src/ViewControllers/MessageDetailViewController.swift

@@ -12,8 +12,17 @@ enum MessageMetadataViewMode: UInt {
     case focusOnMetadata
 }
 
+@objc
+protocol MessageDetailViewDelegate: AnyObject {
+    func detailViewMessageWasDeleted(_ messageDetailViewController: MessageDetailViewController)
+}
+
+@objc
 class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDelegate, OWSMessageBubbleViewDelegate, ContactShareViewHelperDelegate {
 
+    @objc
+    weak var delegate: MessageDetailViewDelegate?
+
     // MARK: Properties
 
     let uiDatabaseConnection: YapDatabaseConnection
@@ -67,7 +76,7 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
         self.viewItem = viewItem
         self.message = message
         self.mode = mode
-        self.uiDatabaseConnection = OWSPrimaryStorage.shared().newDatabaseConnection()
+        self.uiDatabaseConnection = OWSPrimaryStorage.shared().uiDatabaseConnection
         self.conversationStyle = ConversationStyle(thread: thread)
 
         super.init(nibName: nil, bundle: nil)
@@ -80,8 +89,13 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
         self.contactShareViewHelper = ContactShareViewHelper(contactsManager: contactsManager)
         contactShareViewHelper.delegate = self
 
-        self.uiDatabaseConnection.beginLongLivedReadTransaction()
+        do {
-        updateDBConnectionAndMessageToLatest()
+            try updateDBConnectionAndMessageToLatest()
+        } catch DetailViewError.messageWasDeleted {
+            self.delegate?.detailViewMessageWasDeleted(self)
+        } catch {
+            owsFailDebug("unexpected error")
+        }
 
         self.conversationStyle.viewWidth = view.width()
 
@@ -93,8 +107,8 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
         self.view.layoutIfNeeded()
 
         NotificationCenter.default.addObserver(self,
-            selector: #selector(yapDatabaseModified),
+            selector: #selector(uiDatabaseDidUpdate),
-            name: NSNotification.Name.YapDatabaseModified,
+            name: .OWSUIDatabaseConnectionDidUpdate,
             object: OWSPrimaryStorage.shared().dbNotificationObject)
     }
 
@@ -524,19 +538,23 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
 
     // MARK: - Actions
 
+    enum DetailViewError: Error {
+        case messageWasDeleted
+    }
+
     // This method should be called after self.databaseConnection.beginLongLivedReadTransaction().
-    private func updateDBConnectionAndMessageToLatest() {
+    private func updateDBConnectionAndMessageToLatest() throws {
 
         AssertIsOnMainThread()
 
-        self.uiDatabaseConnection.read { transaction in
+        try self.uiDatabaseConnection.read { transaction in
             guard let uniqueId = self.message.uniqueId else {
                 Logger.error("Message is missing uniqueId.")
                 return
             }
             guard let newMessage = TSInteraction.fetch(uniqueId: uniqueId, transaction: transaction) as? TSMessage else {
-                Logger.error("Couldn't reload message.")
+                Logger.error("Message was deleted")
-                return
+                throw DetailViewError.messageWasDeleted
             }
             self.message = newMessage
             self.attachment = self.fetchAttachment(transaction: transaction)
@@ -544,20 +562,25 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
         }
     }
 
-    @objc internal func yapDatabaseModified(notification: NSNotification) {
+    @objc internal func uiDatabaseDidUpdate(notification: NSNotification) {
         AssertIsOnMainThread()
 
         guard !wasDeleted else {
-            // Item was deleted. Don't bother re-rendering, it will fail and we'll soon be dismissed.
+            // Item was deleted in the tile view gallery.
+            // Don't bother re-rendering, it will fail and we'll soon be dismissed.
             return
         }
 
-        let notifications = self.uiDatabaseConnection.beginLongLivedReadTransaction()
+        guard let notifications = notification.userInfo?[OWSUIDatabaseConnectionNotificationsKey] as? [Notification] else {
+            owsFailDebug("notifications was unexpectedly nil")
+            return
+        }
 
         guard let uniqueId = self.message.uniqueId else {
             Logger.error("Message is missing uniqueId.")
             return
         }
+
         guard self.uiDatabaseConnection.hasChange(forKey: uniqueId,
                                                  inCollection: TSInteraction.collection(),
                                                  in: notifications) else {
@@ -565,7 +588,16 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
                                                     return
         }
 
-        updateDBConnectionAndMessageToLatest()
+        do {
+            try updateDBConnectionAndMessageToLatest()
+        } catch DetailViewError.messageWasDeleted {
+            DispatchQueue.main.async {
+                self.delegate?.detailViewMessageWasDeleted(self)
+            }
+            return
+        } catch {
+            owsFailDebug("unexpected error: \(error)")
+        }
         updateContent()
     }
 
@@ -616,14 +648,14 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
     // MARK: OWSMessageBubbleViewDelegate
 
     func didTapImageViewItem(_ viewItem: ConversationViewItem, attachmentStream: TSAttachmentStream, imageView: UIView) {
-        let mediaGallery = MediaGallery(thread: self.thread, uiDatabaseConnection: self.uiDatabaseConnection)
+        let mediaGallery = MediaGallery(thread: self.thread)
 
         mediaGallery.addDataSourceDelegate(self)
         mediaGallery.presentDetailView(fromViewController: self, mediaAttachment: attachmentStream, replacingView: imageView)
     }
 
     func didTapVideoViewItem(_ viewItem: ConversationViewItem, attachmentStream: TSAttachmentStream, imageView: UIView) {
-        let mediaGallery = MediaGallery(thread: self.thread, uiDatabaseConnection: self.uiDatabaseConnection)
+        let mediaGallery = MediaGallery(thread: self.thread)
 
         mediaGallery.addDataSourceDelegate(self)
         mediaGallery.presentDetailView(fromViewController: self, mediaAttachment: attachmentStream, replacingView: imageView)
@@ -732,7 +764,7 @@ class MessageDetailViewController: OWSViewController, MediaGalleryDataSourceDele
 
     // MediaGalleryDataSourceDelegate
 
-    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: MediaGalleryDataSourceDelegate) {
+    func mediaGalleryDataSource(_ mediaGalleryDataSource: MediaGalleryDataSource, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject) {
         Logger.info("")
 
         guard (items.map({ $0.message }) == [self.message]) else {

Signal/src/ViewControllers/ThreadSettings/OWSConversationSettingsViewController.m

@@ -1318,7 +1318,6 @@ const CGFloat kIconViewLength = 24;
     OWSLogDebug(@"");
 
     MediaGallery *mediaGallery = [[MediaGallery alloc] initWithThread:self.thread
-                                                 uiDatabaseConnection:self.uiDatabaseConnection
                                                               options:MediaGalleryOptionSliderEnabled];
 
     self.mediaGallery = mediaGallery;

SignalMessaging/utils/Bench.swift

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 import Foundation
@@ -9,7 +9,10 @@ import Foundation
 ///
 ///     BenchAsync(title: "my benchmark") { completeBenchmark in
 ///         foo {
+///             // consider benchmarking of "foo" complete
 ///             completeBenchmark()
+///
+///             // call any completion handler foo might have
 ///             fooCompletion()
 ///         }
 ///     }
@@ -30,6 +33,21 @@ public func Bench(title: String, block: () -> Void) {
     }
 }
 
+public func Bench(title: String, block: () throws -> Void) throws {
+    var thrownError: Error?
+    BenchAsync(title: title) { finish in
+        do {
+            try block()
+        } catch {
+            thrownError = error
+        }
+        finish()
+    }
+    if let errorToRethrow = thrownError {
+        throw errorToRethrow
+    }
+}
+
 /// When it's not convenient to retain the event completion handler, e.g. when the measured event
 /// crosses multiple classes, you can use the BenchEvent tools
 ///

SignalServiceKit/src/Storage/OWSMediaGalleryFinder.h

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 NS_ASSUME_NONNULL_BEGIN
@@ -7,7 +7,10 @@ NS_ASSUME_NONNULL_BEGIN
 @class OWSStorage;
 @class TSAttachment;
 @class TSThread;
+@class YapDatabaseAutoViewTransaction;
+@class YapDatabaseConnection;
 @class YapDatabaseReadTransaction;
+@class YapDatabaseViewRowChange;
 
 @interface OWSMediaGalleryFinder : NSObject
 
@@ -19,8 +22,8 @@ NS_ASSUME_NONNULL_BEGIN
 - (NSUInteger)mediaCountWithTransaction:(YapDatabaseReadTransaction *)transaction NS_SWIFT_NAME(mediaCount(transaction:));
 
 // The ordinal position of an attachment within a thread's media gallery
-- (NSUInteger)mediaIndexForAttachment:(TSAttachment *)attachment
+- (nullable NSNumber *)mediaIndexForAttachment:(TSAttachment *)attachment
-                          transaction:(YapDatabaseReadTransaction *)transaction
+                                   transaction:(YapDatabaseReadTransaction *)transaction
     NS_SWIFT_NAME(mediaIndex(attachment:transaction:));
 
 - (nullable TSAttachment *)oldestMediaAttachmentWithTransaction:(YapDatabaseReadTransaction *)transaction
@@ -33,8 +36,14 @@ NS_ASSUME_NONNULL_BEGIN
                                      block:(void (^)(TSAttachment *))attachmentBlock
     NS_SWIFT_NAME(enumerateMediaAttachments(range:transaction:block:));
 
+- (BOOL)hasMediaChangesInNotifications:(NSArray<NSNotification *> *)notifications
+                          dbConnection:(YapDatabaseConnection *)dbConnection;
+
 #pragma mark - Extension registration
 
+@property (nonatomic, readonly) NSString *mediaGroup;
+- (YapDatabaseAutoViewTransaction *)galleryExtensionWithTransaction:(YapDatabaseReadTransaction *)transaction
+    NS_SWIFT_NAME(galleryExtension(transaction:));
 + (NSString *)databaseExtensionName;
 + (void)asyncRegisterDatabaseExtensionsWithPrimaryStorage:(OWSStorage *)storage;
 

SignalServiceKit/src/Storage/OWSMediaGalleryFinder.m

@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2019 Open Whisper Systems. All rights reserved.
 //
 
 #import "OWSMediaGalleryFinder.h"
@@ -43,7 +43,8 @@ static NSString *const OWSMediaGalleryFinderExtensionName = @"OWSMediaGalleryFin
     return [[self galleryExtensionWithTransaction:transaction] numberOfItemsInGroup:self.mediaGroup];
 }
 
-- (NSUInteger)mediaIndexForAttachment:(TSAttachment *)attachment transaction:(YapDatabaseReadTransaction *)transaction
+- (nullable NSNumber *)mediaIndexForAttachment:(TSAttachment *)attachment
+                                   transaction:(YapDatabaseReadTransaction *)transaction
 {
     NSString *groupId;
     NSUInteger index;
@@ -53,10 +54,13 @@ static NSString *const OWSMediaGalleryFinderExtensionName = @"OWSMediaGalleryFin
                                                                           forKey:attachment.uniqueId
                                                                     inCollection:[TSAttachment collection]];
 
-    OWSAssertDebug(wasFound);
+    if (!wasFound) {
+        return nil;
+    }
+
     OWSAssertDebug([self.mediaGroup isEqual:groupId]);
 
-    return index;
+    return @(index);
 }
 
 - (nullable TSAttachment *)oldestMediaAttachmentWithTransaction:(YapDatabaseReadTransaction *)transaction
@@ -88,6 +92,15 @@ static NSString *const OWSMediaGalleryFinderExtensionName = @"OWSMediaGalleryFin
                             }];
 }
 
+- (BOOL)hasMediaChangesInNotifications:(NSArray<NSNotification *> *)notifications
+                          dbConnection:(YapDatabaseConnection *)dbConnection
+{
+    YapDatabaseAutoViewConnection *extConnection = [dbConnection ext:OWSMediaGalleryFinderExtensionName];
+    OWSAssert(extConnection);
+
+    return [extConnection hasChangesForGroup:self.mediaGroup inNotifications:notifications];
+}
+
 #pragma mark - Util
 
 - (YapDatabaseAutoViewTransaction *)galleryExtensionWithTransaction:(YapDatabaseReadTransaction *)transaction

SignalServiceKit/src/Util/YapDatabase+Promise.swift

@@ -17,4 +17,36 @@ public extension YapDatabaseConnection {
             self.asyncReadWrite(block, completionBlock: resolver.fulfill)
         }
     }
+
+    func read(_ block: @escaping (YapDatabaseReadTransaction) throws -> Void) throws {
+        var errorToRaise: Error? = nil
+
+        read { transaction in
+            do {
+                try block(transaction)
+            } catch {
+                errorToRaise = error
+            }
+        }
+
+        if let errorToRaise = errorToRaise {
+            throw errorToRaise
+        }
+    }
+
+    func readWrite(_ block: @escaping (YapDatabaseReadWriteTransaction) throws -> Void) throws {
+        var errorToRaise: Error? = nil
+
+        readWrite { transaction in
+            do {
+                try block(transaction)
+            } catch {
+                errorToRaise = error
+            }
+        }
+
+        if let errorToRaise = errorToRaise {
+            throw errorToRaise
+        }
+    }
 }