Merge branch 'charlesmchen/refineUnseenIndicator'

Podfile.lock

@@ -136,7 +136,7 @@ CHECKOUT OPTIONS:
     :commit: 7054e4b13ee5bcd6d524adb6dc9a726e8c466308
     :git: https://github.com/WhisperSystems/JSQMessagesViewController.git
   SignalServiceKit:
-    :commit: c7cc023541c9c7ee098f08f91949263fe0341625
+    :commit: 6acfab6a509f5ca4c0f8f25ac8830b496a97838e
     :git: https://github.com/WhisperSystems/SignalServiceKit.git
   SocketRocket:
     :commit: 877ac7438be3ad0b45ef5ca3969574e4b97112bf

Signal/src/Models/OWSCall.m

@@ -17,7 +17,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) TSMessageAdapterType messageType;
 @property (nonatomic) BOOL isExpiringMessage;
 @property (nonatomic) BOOL shouldStartExpireTimer;
-@property (nonatomic) uint64_t expiresAtSeconds;
+@property (nonatomic) double expiresAtSeconds;
 @property (nonatomic) uint32_t expiresInSeconds;
 @property (nonatomic) TSInteraction *interaction;
 
@@ -85,7 +85,7 @@ NS_ASSUME_NONNULL_BEGIN
     return [self initWithInteraction:callRecord
                             callerId:contactThread.contactIdentifier
                    callerDisplayName:name
-                                date:callRecord.date
+                                date:callRecord.dateForSorting
                               status:status
                        displayString:detailString];
 }

Signal/src/Models/OWSMessagesBubblesSizeCalculator.m

@@ -5,10 +5,12 @@
 #import "OWSMessagesBubblesSizeCalculator.h"
 #import "OWSCall.h"
 #import "OWSDisplayedMessageCollectionViewCell.h"
+#import "OWSUnreadIndicatorCell.h"
 #import "TSGenericAttachmentAdapter.h"
 #import "TSMessageAdapter.h"
 #import "UIFont+OWS.h"
 #import "tgmath.h" // generic math allows fmax to handle CGFLoat correctly on 32 & 64bit.
+#import <JSQMessagesViewController/JSQMessagesCollectionView.h>
 #import <JSQMessagesViewController/JSQMessagesCollectionViewFlowLayout.h>
 
 NS_ASSUME_NONNULL_BEGIN
@@ -50,6 +52,11 @@ NS_ASSUME_NONNULL_BEGIN
         TSMessageAdapter *message = (TSMessageAdapter *)messageData;
         if (message.messageType == TSInfoMessageAdapter || message.messageType == TSErrorMessageAdapter) {
             return [self messageBubbleSizeForInfoMessageData:messageData atIndexPath:indexPath withLayout:layout];
+        } else if (message.messageType == TSUnreadIndicatorAdapter) {
+            return [OWSUnreadIndicatorCell
+                cellSizeForInteraction:(TSUnreadIndicatorInteraction *)((TSMessageAdapter *)messageData).interaction
+                   collectionViewWidth:layout.collectionView.bounds.size.width];
+            return [self messageBubbleSizeForInfoMessageData:messageData atIndexPath:indexPath withLayout:layout];
         }
     }
 
@@ -132,7 +139,9 @@ NS_ASSUME_NONNULL_BEGIN
                                   atIndexPath:(NSIndexPath *)indexPath
                                    withLayout:(JSQMessagesCollectionViewFlowLayout *)layout
 {
-    NSValue *cachedSize = [self.cache objectForKey:@([messageData messageHash])];
+    id cacheKey = [self cacheKeyForMessageData:messageData];
+
+    NSValue *cachedSize = [self.cache objectForKey:cacheKey];
     if (cachedSize != nil) {
         return [cachedSize CGSizeValue];
     }
@@ -199,7 +208,7 @@ NS_ASSUME_NONNULL_BEGIN
         finalSize = CGSizeMake(finalWidth, stringSize.height + verticalInsets);
     }
 
-    [self.cache setObject:[NSValue valueWithCGSize:finalSize] forKey:@([messageData messageHash])];
+    [self.cache setObject:[NSValue valueWithCGSize:finalSize] forKey:cacheKey];
 
     return finalSize;
 }
@@ -208,7 +217,9 @@ NS_ASSUME_NONNULL_BEGIN
                            atIndexPath:(NSIndexPath *)indexPath
                             withLayout:(JSQMessagesCollectionViewFlowLayout *)layout
 {
-    NSValue *cachedSize = [self.cache objectForKey:@([messageData messageHash])];
+    id cacheKey = [self cacheKeyForMessageData:messageData];
+
+    NSValue *cachedSize = [self.cache objectForKey:cacheKey];
     if (cachedSize != nil) {
         return [cachedSize CGSizeValue];
     }
@@ -232,11 +243,21 @@ NS_ASSUME_NONNULL_BEGIN
 
     CGSize finalSize = CGSizeMake(finalWidth, stringSize.height + verticalInsets);
 
-    [self.cache setObject:[NSValue valueWithCGSize:finalSize] forKey:@([messageData messageHash])];
+    [self.cache setObject:[NSValue valueWithCGSize:finalSize] forKey:cacheKey];
 
     return finalSize;
 }
 
+- (id)cacheKeyForMessageData:(id<JSQMessageData>)messageData
+{
+    OWSAssert(messageData);
+    OWSAssert([messageData conformsToProtocol:@protocol(OWSMessageData)]);
+    OWSAssert(((id<OWSMessageData>)messageData).interaction);
+    OWSAssert(((id<OWSMessageData>)messageData).interaction.uniqueId);
+
+    return @([messageData messageHash]);
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

Signal/src/Models/TSMessageAdapaters/OWSMessageData.h

@@ -24,7 +24,7 @@ typedef NS_ENUM(NSInteger, TSMessageAdapterType) {
 @property (nonatomic, readonly) TSInteraction *interaction;
 @property (nonatomic, readonly) BOOL isExpiringMessage;
 @property (nonatomic, readonly) BOOL shouldStartExpireTimer;
-@property (nonatomic, readonly) uint64_t expiresAtSeconds;
+@property (nonatomic, readonly) double expiresAtSeconds;
 @property (nonatomic, readonly) uint32_t expiresInSeconds;
 
 @end

Signal/src/Models/TSMessageAdapaters/TSMessageAdapter.m

@@ -54,10 +54,9 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) TSMessageAdapterType messageType;
 @property (nonatomic) BOOL isExpiringMessage;
 @property (nonatomic) BOOL shouldStartExpireTimer;
-@property (nonatomic) uint64_t expiresAtSeconds;
+@property (nonatomic) double expiresAtSeconds;
 @property (nonatomic) uint32_t expiresInSeconds;
 
-@property (nonatomic) NSDate *messageDate;
 @property (nonatomic) NSString *messageBody;
 
 @property (nonatomic) NSString *interactionUniqueId;
@@ -76,14 +75,13 @@ NS_ASSUME_NONNULL_BEGIN
     }
 
     _interaction = interaction;
-    _messageDate = interaction.date;
 
     self.interactionUniqueId = interaction.uniqueId;
 
     if ([interaction isKindOfClass:[TSMessage class]]) {
         TSMessage *message = (TSMessage *)interaction;
         _isExpiringMessage = message.isExpiringMessage;
-        _expiresAtSeconds = message.expiresAt / 1000;
+        _expiresAtSeconds = message.expiresAt / 1000.0;
         _expiresInSeconds = message.expiresInSeconds;
         _shouldStartExpireTimer = message.shouldStartExpireTimer;
     } else {
@@ -93,6 +91,18 @@ NS_ASSUME_NONNULL_BEGIN
     return self;
 }
 
++ (NSCache *)displayableTextCache
+{
+    static NSCache *cache = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        cache = [NSCache new];
+        // Cache the results for up to 1,000 messages.
+        cache.countLimit = 1000;
+    });
+    return cache;
+}
+
 + (id<OWSMessageData>)messageViewDataWithInteraction:(TSInteraction *)interaction inThread:(TSThread *)thread contactsManager:(id<ContactsManagerProtocol>)contactsManager
 {
     TSMessageAdapter *adapter = [[TSMessageAdapter alloc] initWithInteraction:interaction];
@@ -138,23 +148,30 @@ NS_ASSUME_NONNULL_BEGIN
                 if ([attachment isKindOfClass:[TSAttachmentStream class]]) {
                     TSAttachmentStream *stream = (TSAttachmentStream *)attachment;
                     if ([attachment.contentType isEqualToString:OWSMimeTypeOversizeTextMessage]) {
-                        NSData *textData = [NSData dataWithContentsOfURL:stream.mediaURL];
-                        NSString *fullText = [[NSString alloc] initWithData:textData encoding:NSUTF8StringEncoding];
-                        // Only show up to 2kb of text.
-                        const NSUInteger kMaxTextDisplayLength = 2 * 1024;
-                        NSString *displayText = [[DisplayableTextFilter new] displayableText:fullText];
-                        if (displayText.length > kMaxTextDisplayLength) {
-                            // Trim whitespace before _AND_ after slicing the snipper from the string.
-                            NSString *snippet =
-                                [[[displayText stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]
+                        NSString *displayableText = [[self displayableTextCache] objectForKey:interaction.uniqueId];
+                        if (!displayableText) {
+                            NSData *textData = [NSData dataWithContentsOfURL:stream.mediaURL];
+                            NSString *fullText = [[NSString alloc] initWithData:textData encoding:NSUTF8StringEncoding];
+                            // Only show up to 2kb of text.
+                            const NSUInteger kMaxTextDisplayLength = 2 * 1024;
+                            displayableText = [[DisplayableTextFilter new] displayableText:fullText];
+                            if (displayableText.length > kMaxTextDisplayLength) {
+                                // Trim whitespace before _AND_ after slicing the snipper from the string.
+                                NSString *snippet = [[[displayableText
+                                    stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]
                                     substringWithRange:NSMakeRange(0, kMaxTextDisplayLength)]
                                     stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
-                            displayText =
-                                [NSString stringWithFormat:NSLocalizedString(@"OVERSIZE_TEXT_DISPLAY_FORMAT",
-                                                               @"A display format for oversize text messages."),
-                                          snippet];
+                                displayableText =
+                                    [NSString stringWithFormat:NSLocalizedString(@"OVERSIZE_TEXT_DISPLAY_FORMAT",
+                                                                   @"A display format for oversize text messages."),
+                                              snippet];
+                            }
+                            if (!displayableText) {
+                                displayableText = @"";
+                            }
+                            [[self displayableTextCache] setObject:displayableText forKey:interaction.uniqueId];
                         }
-                        adapter.messageBody = displayText;
+                        adapter.messageBody = displayableText;
                     } else if ([stream isAnimated]) {
                         adapter.mediaItem =
                             [[TSAnimatedAdapter alloc] initWithAttachment:stream incoming:isIncomingAttachment];
@@ -188,6 +205,16 @@ NS_ASSUME_NONNULL_BEGIN
                                NSStringFromClass([attachment class]));
                 }
             }
+        } else {
+            NSString *displayableText = [[self displayableTextCache] objectForKey:interaction.uniqueId];
+            if (!displayableText) {
+                displayableText = [[DisplayableTextFilter new] displayableText:message.body];
+                if (!displayableText) {
+                    displayableText = @"";
+                }
+                [[self displayableTextCache] setObject:displayableText forKey:interaction.uniqueId];
+            }
+            adapter.messageBody = displayableText;
         }
     } else if ([interaction isKindOfClass:[TSCall class]]) {
         TSCall *callRecord = (TSCall *)interaction;
@@ -246,7 +273,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (NSDate *)date {
-    return self.messageDate;
+    return self.interaction.dateForSorting;
 }
 
 #pragma mark - OWSMessageEditing Protocol

Signal/src/UIView+OWS.m

@@ -167,8 +167,8 @@ CGFloat ScaleFromIPhone5(CGFloat iPhone5Value)
 {
     OWSAssert(self.superview);
 
-    self.frame = CGRectMake(round(self.superview.left + (self.superview.width - self.width) * 0.5f),
-        round(self.superview.top + (self.superview.height - self.height) * 0.5f),
+    self.frame = CGRectMake(round((self.superview.width - self.width) * 0.5f),
+        round((self.superview.height - self.height) * 0.5f),
         self.width,
         self.height);
 }

Signal/src/ViewControllers/MessagesViewController.m

@@ -81,12 +81,18 @@
 
 @import Photos;
 
-#define kYapDatabaseRangeLength 50
-#define kYapDatabaseRangeMaxLength 300
-#define kYapDatabaseRangeMinLength 20
-#define JSQ_TOOLBAR_ICON_HEIGHT 22
-#define JSQ_TOOLBAR_ICON_WIDTH 22
-#define JSQ_IMAGE_INSET 5
+// Always load up to 50 messages when user arrives.
+static const int kYapDatabasePageSize = 50;
+// Never show more than 50*50 = 2,500 messages in conversation view at a time.
+static const int kYapDatabaseMaxPageCount = 50;
+// Never show more than 6*50 = 300 messages in conversation view when user
+// arrives.
+static const int kYapDatabaseMaxInitialPageCount = 6;
+static const int kYapDatabaseRangeMaxLength = kYapDatabasePageSize * kYapDatabaseMaxPageCount;
+static const int kYapDatabaseRangeMinLength = 0;
+static const int JSQ_TOOLBAR_ICON_HEIGHT = 22;
+static const int JSQ_TOOLBAR_ICON_WIDTH = 22;
+static const int JSQ_IMAGE_INSET = 5;
 
 static NSTimeInterval const kTSMessageSentDateShowTimeInterval = 5 * 60;
 
@@ -97,6 +103,8 @@ typedef enum : NSUInteger {
     kMediaTypeVideo,
 } kMediaTypes;
 
+#pragma mark -
+
 @protocol OWSTextViewPasteDelegate <NSObject>
 
 - (void)didPasteAttachment:(SignalAttachment * _Nullable)attachment;
@@ -761,7 +769,23 @@ typedef enum : NSUInteger {
       [self.messageMappings updateWithTransaction:transaction];
     }];
     self.page = 0;
-    [self updateRangeOptionsForPage:self.page];
+
+    if (self.offersAndIndicators.unreadIndicatorPosition != nil) {
+        long unreadIndicatorPosition = [self.offersAndIndicators.unreadIndicatorPosition longValue];
+        // If there is an unread indicator, increase the initial load window
+        // to include it.
+        OWSAssert(unreadIndicatorPosition > 0);
+        OWSAssert(unreadIndicatorPosition <= kYapDatabaseRangeMaxLength);
+
+        // We'd like to include at least N seen messages, if possible,
+        // to give the user the context of where they left off the conversation.
+        const int kPreferredSeenMessageCount = 1;
+        self.page = (NSUInteger)MAX(0,
+            MIN(kYapDatabaseMaxInitialPageCount - 1,
+                (unreadIndicatorPosition + kPreferredSeenMessageCount) / kYapDatabasePageSize));
+    }
+
+    [self updateMessageMappingRangeOptions];
     [self updateLoadEarlierVisible];
     [self.collectionView reloadData];
 }
@@ -843,6 +867,7 @@ typedef enum : NSUInteger {
         // invalidate layout
         [self.collectionView.collectionViewLayout
             invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
+        self.collectionView.collectionViewLayout.bubbleSizeCalculator = [[OWSMessagesBubblesSizeCalculator alloc] init];
     }
 }
 
@@ -886,15 +911,7 @@ typedef enum : NSUInteger {
                                                      name:YapDatabaseModifiedNotification
                                                    object:nil];
         [[NSNotificationCenter defaultCenter] addObserver:self
-                                                 selector:@selector(startReadTimer)
-                                                     name:UIApplicationWillEnterForegroundNotification
-                                                   object:nil];
-        [[NSNotificationCenter defaultCenter] addObserver:self
-                                                 selector:@selector(startExpirationTimerAnimations)
-                                                     name:UIApplicationWillEnterForegroundNotification
-                                                   object:nil];
-        [[NSNotificationCenter defaultCenter] addObserver:self
-                                                 selector:@selector(resetContentAndLayout)
+                                                 selector:@selector(applicationWillEnterForeground:)
                                                      name:UIApplicationWillEnterForegroundNotification
                                                    object:nil];
         [[NSNotificationCenter defaultCenter] addObserver:self
@@ -924,6 +941,14 @@ typedef enum : NSUInteger {
     }
 }
 
+- (void)applicationWillEnterForeground:(NSNotification *)notification
+{
+    [self resetContentAndLayout];
+    [self startReadTimer];
+    [self startExpirationTimerAnimations];
+    [self ensureThreadOffersAndIndicators];
+}
+
 - (void)applicationWillResignActive:(NSNotification *)notification
 {
     [self cancelVoiceMemo];
@@ -944,6 +969,16 @@ typedef enum : NSUInteger {
 
 - (void)viewWillAppear:(BOOL)animated
 {
+    // We need to update the dynamic interactions before we do any layout.
+    [self ensureThreadOffersAndIndicators];
+
+    // Triggering modified notification renders "call notification" when leaving full screen call view
+    [self.thread touch];
+
+    [self ensureBlockStateIndicator];
+
+    [self resetContentAndLayout];
+
     [super viewWillAppear:animated];
 
     // In case we're dismissing a CNContactViewController which requires default system appearance
@@ -958,16 +993,11 @@ typedef enum : NSUInteger {
 
     [self toggleObservers:YES];
 
-    [self ensureThreadOffersAndIndicators];
-
-    // Triggering modified notification renders "call notification" when leaving full screen call view
-    [self.thread touch];
-
     // restart any animations that were stopped e.g. while inspecting the contact info screens.
     [self startExpirationTimerAnimations];
 
     // We should have already requested contact access at this point, so this should be a no-op
-    // unless it ever becomes possible to to load this VC without going via the SignalsViewController
+    // unless it ever becomes possible to load this VC without going via the SignalsViewController.
     [self.contactsManager requestSystemContactsOnce];
 
     OWSDisappearingMessagesConfiguration *configuration =
@@ -988,15 +1018,9 @@ typedef enum : NSUInteger {
                                    action:shareSelector],
     ];
 
-    [self ensureBlockStateIndicator];
-
-    [self resetContentAndLayout];
 
     [((OWSMessagesToolbarContentView *)self.inputToolbar.contentView)ensureSubviews];
 
-    [self.collectionView.collectionViewLayout
-        invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
-
     [self.scrollLaterTimer invalidate];
     // We want to scroll to the bottom _after_ the layout has been updated.
     self.scrollLaterTimer = [NSTimer weakScheduledTimerWithTimeInterval:0.001f
@@ -1026,18 +1050,40 @@ typedef enum : NSUInteger {
 
     NSIndexPath *_Nullable indexPath = [self indexPathOfUnreadMessagesIndicator];
     if (indexPath) {
-        [self.collectionView scrollToItemAtIndexPath:indexPath
-                                    atScrollPosition:UICollectionViewScrollPositionTop
-                                            animated:NO];
+        if (indexPath.section == 0 && indexPath.row == 0) {
+            [self.collectionView setContentOffset:CGPointZero animated:NO];
+        } else {
+            [self.collectionView scrollToItemAtIndexPath:indexPath
+                                        atScrollPosition:UICollectionViewScrollPositionTop
+                                                animated:NO];
+        }
     } else {
         [self scrollToBottomAnimated:NO];
     }
 }
 
+- (void)scrollToUnreadIndicatorAnimated
+{
+    [self.scrollLaterTimer invalidate];
+    self.scrollLaterTimer = nil;
+
+    NSIndexPath *_Nullable indexPath = [self indexPathOfUnreadMessagesIndicator];
+    if (indexPath) {
+        if (indexPath.section == 0 && indexPath.row == 0) {
+            [self.collectionView setContentOffset:CGPointZero animated:YES];
+        } else {
+            [self.collectionView scrollToItemAtIndexPath:indexPath
+                                        atScrollPosition:UICollectionViewScrollPositionTop
+                                                animated:YES];
+        }
+    }
+}
+
 - (void)resetContentAndLayout
 {
     // Avoid layout corrupt issues and out-of-date message subtitles.
-    [self.collectionView.collectionViewLayout invalidateLayout];
+    [self.collectionView.collectionViewLayout
+        invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
     [self.collectionView reloadData];
 }
 
@@ -1516,7 +1562,6 @@ typedef enum : NSUInteger {
     self.outgoingBubbleImageData = [bubbleFactory outgoingMessagesBubbleImageWithColor:[UIColor ows_materialBlueColor]];
     self.currentlyOutgoingBubbleImageData = [bubbleFactory outgoingMessagesBubbleImageWithColor:[UIColor ows_fadedBlueColor]];
     self.outgoingMessageFailedImageData = [bubbleFactory outgoingMessagesBubbleImageWithColor:[UIColor grayColor]];
-
 }
 
 #pragma mark - Identity
@@ -1851,26 +1896,33 @@ typedef enum : NSUInteger {
         case TSCallAdapter: {
             OWSCall *call = (OWSCall *)message;
             cell = [self loadCallCellForCall:call atIndexPath:indexPath];
-        } break;
+            break;
+        }
         case TSInfoMessageAdapter: {
             cell = [self loadInfoMessageCellForMessage:(TSMessageAdapter *)message atIndexPath:indexPath];
-        } break;
+            break;
+        }
         case TSErrorMessageAdapter: {
             cell = [self loadErrorMessageCellForMessage:(TSMessageAdapter *)message atIndexPath:indexPath];
-        } break;
+            break;
+        }
         case TSIncomingMessageAdapter: {
             cell = [self loadIncomingMessageCellForMessage:message atIndexPath:indexPath];
-        } break;
+            break;
+        }
         case TSOutgoingMessageAdapter: {
             cell = [self loadOutgoingCellForMessage:message atIndexPath:indexPath];
-        } break;
+            break;
+        }
         case TSUnreadIndicatorAdapter: {
-            cell = [self loadUnreadIndicatorCell:indexPath];
-        } break;
+            cell = [self loadUnreadIndicatorCell:indexPath interaction:message.interaction];
+            break;
+        }
         default: {
             DDLogWarn(@"using default cell constructor for message: %@", message);
             cell = (JSQMessagesCollectionViewCell *)[super collectionView:collectionView cellForItemAtIndexPath:indexPath];
-        } break;
+            break;
+        }
     }
     cell.delegate = collectionView;
 
@@ -1937,12 +1989,18 @@ typedef enum : NSUInteger {
 }
 
 - (JSQMessagesCollectionViewCell *)loadUnreadIndicatorCell:(NSIndexPath *)indexPath
+                                               interaction:(TSInteraction *)interaction
 {
     OWSAssert(indexPath);
+    OWSAssert(interaction);
+    OWSAssert([interaction isKindOfClass:[TSUnreadIndicatorInteraction class]]);
+
+    TSUnreadIndicatorInteraction *unreadIndicator = (TSUnreadIndicatorInteraction *)interaction;
 
     OWSUnreadIndicatorCell *cell =
         [self.collectionView dequeueReusableCellWithReuseIdentifier:[OWSUnreadIndicatorCell cellReuseIdentifier]
                                                        forIndexPath:indexPath];
+    cell.interaction = unreadIndicator;
     [cell configure];
 
     return cell;
@@ -2484,25 +2542,69 @@ typedef enum : NSUInteger {
 
 - (void)collectionView:(JSQMessagesCollectionView *)collectionView
                              header:(JSQMessagesLoadEarlierHeaderView *)headerView
-    didTapLoadEarlierMessagesButton:(UIButton *)sender {
-    if ([self shouldShowLoadEarlierMessages]) {
-        self.page++;
-    }
+    didTapLoadEarlierMessagesButton:(UIButton *)sender
+{
 
-    [self.scrollLaterTimer invalidate];
-    self.scrollLaterTimer = nil;
-    NSInteger item = (NSInteger)[self scrollToItem];
+    // We want to restore the current scroll state after we update the range, update
+    // the dynamic interactions and re-layout.  Here we take a "before" snapshot.
+    CGFloat scrollDistanceToBottom = self.collectionView.contentSize.height - self.collectionView.contentOffset.y;
 
-    [self updateRangeOptionsForPage:self.page];
+    self.page = MIN(self.page + 1, (NSUInteger)kYapDatabaseMaxPageCount - 1);
+
+    // To update a YapDatabaseViewMappings, you can call either:
+    //
+    // * [YapDatabaseViewMappings updateWithTransaction]
+    // * [YapDatabaseViewMappings getSectionChanges:rowChanges:forNotifications:withMappings:]
+    //
+    // ...but you can't call both.
+    //
+    // If ensureThreadOffersAndIndicators modifies the database,
+    // the mappings will be updated by yapDatabaseModified.
+    // This will leave the mapping range in a bad state.
+    // Therefore we temporarily disable observation of YapDatabaseModifiedNotification
+    // while updating the range and the dynamic interactions.
+    [[NSNotificationCenter defaultCenter] removeObserver:self name:YapDatabaseModifiedNotification object:nil];
+
+    // We need to update the dynamic interactions after loading earlier messages,
+    // since the unseen indicator may need to move or change.
+    [self ensureThreadOffersAndIndicators];
 
+    [self updateMessageMappingRangeOptions];
+
+    // We need to `beginLongLivedReadTransaction` before we update our
+    // mapping in order to jump to the most recent commit.
+    [self.uiDatabaseConnection beginLongLivedReadTransaction];
     [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-      [self.messageMappings updateWithTransaction:transaction];
+        [self.messageMappings updateWithTransaction:transaction];
     }];
 
-    [self updateLayoutForEarlierMessagesWithOffset:item];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(yapDatabaseModified:)
+                                                 name:YapDatabaseModifiedNotification
+                                               object:nil];
+
+    [self.collectionView.collectionViewLayout
+        invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
+    [self.collectionView reloadData];
+    [self.collectionView layoutSubviews];
+
+    self.collectionView.contentOffset = CGPointMake(0, self.collectionView.contentSize.height - scrollDistanceToBottom);
+    [self.scrollLaterTimer invalidate];
+    // We want to scroll to the bottom _after_ the layout has been updated.
+    self.scrollLaterTimer = [NSTimer weakScheduledTimerWithTimeInterval:0.001f
+                                                                 target:self
+                                                               selector:@selector(scrollToUnreadIndicatorAnimated)
+                                                               userInfo:nil
+                                                                repeats:NO];
+
+    [self updateLoadEarlierVisible];
 }
 
 - (BOOL)shouldShowLoadEarlierMessages {
+    if (self.page == kYapDatabaseMaxPageCount - 1) {
+        return NO;
+    }
+
     __block BOOL show = YES;
 
     [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
@@ -2513,48 +2615,14 @@ typedef enum : NSUInteger {
     return show;
 }
 
-- (NSUInteger)scrollToItem {
-    __block NSUInteger item =
-        kYapDatabaseRangeLength * (self.page + 1) - [self.messageMappings numberOfItemsInGroup:self.thread.uniqueId];
-
-    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-
-      NSUInteger numberOfVisibleMessages = [self.messageMappings numberOfItemsInGroup:self.thread.uniqueId];
-      NSUInteger numberOfTotalMessages =
-          [[transaction ext:TSMessageDatabaseViewExtensionName] numberOfItemsInGroup:self.thread.uniqueId];
-      NSUInteger numberOfMessagesToLoad = numberOfTotalMessages - numberOfVisibleMessages;
-
-      BOOL canLoadFullRange = numberOfMessagesToLoad >= kYapDatabaseRangeLength;
-
-      if (!canLoadFullRange) {
-          item = numberOfMessagesToLoad;
-      }
-    }];
-
-    return item == 0 ? item : item - 1;
-}
-
 - (void)updateLoadEarlierVisible {
     [self setShowLoadEarlierMessagesHeader:[self shouldShowLoadEarlierMessages]];
 }
 
-- (void)updateLayoutForEarlierMessagesWithOffset:(NSInteger)offset {
-    [self.collectionView.collectionViewLayout
-        invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
-    [self.collectionView reloadData];
-
-    [self.scrollLaterTimer invalidate];
-    self.scrollLaterTimer = nil;
-    [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:offset inSection:0]
-                                atScrollPosition:UICollectionViewScrollPositionTop
-                                        animated:NO];
-
-    [self updateLoadEarlierVisible];
-}
-
-- (void)updateRangeOptionsForPage:(NSUInteger)page {
+- (void)updateMessageMappingRangeOptions
+{
     YapDatabaseViewRangeOptions *rangeOptions =
-        [YapDatabaseViewRangeOptions flexibleRangeWithLength:kYapDatabaseRangeLength * (page + 1)
+        [YapDatabaseViewRangeOptions flexibleRangeWithLength:kYapDatabasePageSize * (self.page + 1)
                                                       offset:0
                                                         from:YapDatabaseViewEnd];
 
@@ -2859,15 +2927,18 @@ typedef enum : NSUInteger {
 {
     OWSAssert([NSThread isMainThread]);
 
+    const int initialMaxRangeSize = kYapDatabasePageSize * kYapDatabaseMaxInitialPageCount;
+    const int currentMaxRangeSize = (int)(self.page + 1) * kYapDatabasePageSize;
+    const int maxRangeSize = MAX(initialMaxRangeSize, currentMaxRangeSize);
+
     self.offersAndIndicators =
         [ThreadUtil ensureThreadOffersAndIndicators:self.thread
                                      storageManager:self.storageManager
                                     contactsManager:self.contactsManager
                                     blockingManager:self.blockingManager
                         hideUnreadMessagesIndicator:self.hasClearedUnreadMessagesIndicator
-                      fixedUnreadIndicatorTimestamp:(self.offersAndIndicators.unreadIndicator
-                                                            ? @(self.offersAndIndicators.unreadIndicator.timestamp)
-                                                            : nil)];
+                    firstUnseenInteractionTimestamp:self.offersAndIndicators.firstUnseenInteractionTimestamp
+                                       maxRangeSize:maxRangeSize];
 }
 
 - (void)clearUnreadMessagesIndicator
@@ -3326,55 +3397,56 @@ typedef enum : NSUInteger {
     __block BOOL scrollToBottom = wasAtBottom;
 
     [self.collectionView performBatchUpdates:^{
-      for (YapDatabaseViewRowChange *rowChange in messageRowChanges) {
-          switch (rowChange.type) {
-              case YapDatabaseViewChangeDelete: {
-                  [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
-
-                  YapCollectionKey *collectionKey = rowChange.collectionKey;
-                  if (collectionKey.key) {
-                      [self.messageAdapterCache removeObjectForKey:collectionKey.key];
-                  }
-                  
-                  break;
-              }
-              case YapDatabaseViewChangeInsert: {
-                  [self.collectionView insertItemsAtIndexPaths:@[ rowChange.newIndexPath ]];
-                  
-                  TSInteraction *interaction = [self interactionAtIndexPath:rowChange.newIndexPath];
-                  if ([interaction isKindOfClass:[TSOutgoingMessage class]]) {
-                      scrollToBottom = YES;
-                      shouldAnimateScrollToBottom = NO;
-                  }
-                  break;
-              }
-              case YapDatabaseViewChangeMove: {
-                  [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
-                  [self.collectionView insertItemsAtIndexPaths:@[ rowChange.newIndexPath ]];
-                  break;
-              }
-              case YapDatabaseViewChangeUpdate: {
-                  YapCollectionKey *collectionKey = rowChange.collectionKey;
-                  if (collectionKey.key) {
-                      [self.messageAdapterCache removeObjectForKey:collectionKey.key];
-                  }
-                  [self.collectionView reloadItemsAtIndexPaths:@[ rowChange.indexPath ]];
-                  break;
-              }
-          }
-      }
+        for (YapDatabaseViewRowChange *rowChange in messageRowChanges) {
+            switch (rowChange.type) {
+                case YapDatabaseViewChangeDelete: {
+                    [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
+
+                    YapCollectionKey *collectionKey = rowChange.collectionKey;
+                    if (collectionKey.key) {
+                        [self.messageAdapterCache removeObjectForKey:collectionKey.key];
+                    }
+
+                    break;
+                }
+                case YapDatabaseViewChangeInsert: {
+                    [self.collectionView insertItemsAtIndexPaths:@[ rowChange.newIndexPath ]];
+
+                    TSInteraction *interaction = [self interactionAtIndexPath:rowChange.newIndexPath];
+                    if ([interaction isKindOfClass:[TSOutgoingMessage class]]) {
+                        scrollToBottom = YES;
+                        shouldAnimateScrollToBottom = NO;
+                    }
+                    break;
+                }
+                case YapDatabaseViewChangeMove: {
+                    [self.collectionView deleteItemsAtIndexPaths:@[ rowChange.indexPath ]];
+                    [self.collectionView insertItemsAtIndexPaths:@[ rowChange.newIndexPath ]];
+                    break;
+                }
+                case YapDatabaseViewChangeUpdate: {
+                    YapCollectionKey *collectionKey = rowChange.collectionKey;
+                    if (collectionKey.key) {
+                        [self.messageAdapterCache removeObjectForKey:collectionKey.key];
+                    }
+                    [self.collectionView reloadItemsAtIndexPaths:@[ rowChange.indexPath ]];
+                    break;
+                }
+            }
+        }
     }
         completion:^(BOOL success) {
-          if (!success) {
-              [self.collectionView.collectionViewLayout
-                  invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
-              [self.collectionView reloadData];
-          }
-          if (scrollToBottom) {
-              [self.scrollLaterTimer invalidate];
-              self.scrollLaterTimer = nil;
-              [self scrollToBottomAnimated:shouldAnimateScrollToBottom];
-          }
+            if (!success) {
+                [self.collectionView.collectionViewLayout
+                    invalidateLayoutWithContext:[JSQMessagesCollectionViewFlowLayoutInvalidationContext context]];
+                [self.collectionView reloadData];
+            }
+
+            if (scrollToBottom) {
+                [self.scrollLaterTimer invalidate];
+                self.scrollLaterTimer = nil;
+                [self scrollToBottomAnimated:shouldAnimateScrollToBottom];
+            }
         }];
 }
 
@@ -3392,26 +3464,23 @@ typedef enum : NSUInteger {
     return numberOfMessages;
 }
 
-- (TSInteraction *)interactionAtIndexPath:(NSIndexPath *)indexPath {
-    __block TSInteraction *message = nil;
+- (TSInteraction *)interactionAtIndexPath:(NSIndexPath *)indexPath
+{
+    OWSAssert(indexPath);
+    OWSAssert(indexPath.section == 0);
+    OWSAssert(self.messageMappings);
+
+    __block TSInteraction *interaction;
+
     [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-      YapDatabaseViewTransaction *viewTransaction = [transaction ext:TSMessageDatabaseViewExtensionName];
-      NSParameterAssert(viewTransaction != nil);
-      NSParameterAssert(self.messageMappings != nil);
-      NSParameterAssert(indexPath != nil);
-      NSUInteger row                    = (NSUInteger)indexPath.row;
-      NSUInteger section                = (NSUInteger)indexPath.section;
-      NSUInteger numberOfItemsInSection __unused = [self.messageMappings numberOfItemsInSection:section];
-      NSAssert(row < numberOfItemsInSection,
-               @"Cannot fetch message because row %d is >= numberOfItemsInSection %d",
-               (int)row,
-               (int)numberOfItemsInSection);
-
-      message = [viewTransaction objectAtRow:row inSection:section withMappings:self.messageMappings];
-      NSParameterAssert(message != nil);
+        YapDatabaseViewTransaction *viewTransaction = [transaction ext:TSMessageDatabaseViewExtensionName];
+        OWSAssert(viewTransaction);
+        interaction = [viewTransaction objectAtRow:(NSUInteger)indexPath.row
+                                         inSection:(NSUInteger)indexPath.section
+                                      withMappings:self.messageMappings];
+        OWSAssert(interaction);
     }];
-
-    return message;
+    return interaction;
 }
 
 - (id<OWSMessageData>)messageAtIndexPath:(NSIndexPath *)indexPath

Signal/src/ViewControllers/SignalsViewController.m

@@ -336,7 +336,7 @@ NSString *const SignalsViewControllerSegueShowIncomingCall = @"ShowIncomingCallS
 
 #pragma mark - startup
 
-- (void)displayAnyUnseenUpgradeExperience
+- (NSArray<ExperienceUpgrade *> *)unseenUpgradeExperiences
 {
     AssertIsOnMainThread();
 
@@ -344,14 +344,31 @@ NSString *const SignalsViewControllerSegueShowIncomingCall = @"ShowIncomingCallS
     [self.editingDbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         unseenUpgrades = [self.experienceUpgradeFinder allUnseenWithTransaction:transaction];
     }];
+    return unseenUpgrades;
+}
+
+- (void)markAllUpgradeExperiencesAsSeen
+{
+    AssertIsOnMainThread();
+
+    [self.editingDbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *_Nonnull transaction) {
+        [self.experienceUpgradeFinder markAllAsSeenWithTransaction:transaction];
+    }];
+}
+
+- (void)displayAnyUnseenUpgradeExperience
+{
+    AssertIsOnMainThread();
+
+    NSArray<ExperienceUpgrade *> *unseenUpgrades = [self unseenUpgradeExperiences];
 
     if (unseenUpgrades.count > 0) {
         ExperienceUpgradesPageViewController *experienceUpgradeViewController = [[ExperienceUpgradesPageViewController alloc] initWithExperienceUpgrades:unseenUpgrades];
-        [self presentViewController:experienceUpgradeViewController animated:YES completion:^{
-            [self.editingDbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction * _Nonnull transaction) {
-                [self.experienceUpgradeFinder markAllAsSeenWithTransaction:transaction];
-            }];
-        }];
+        [self presentViewController:experienceUpgradeViewController
+                           animated:YES
+                         completion:^{
+                             [self markAllUpgradeExperiencesAsSeen];
+                         }];
     }
 }
 
@@ -773,7 +790,6 @@ NSString *const SignalsViewControllerSegueShowIncomingCall = @"ShowIncomingCallS
     [self checkIfEmptyView];
 }
 
-
 - (IBAction)unwindSettingsDone:(UIStoryboardSegue *)segue {
 }
 

Signal/src/contact/OWSContactsManager.m

@@ -47,6 +47,7 @@ NSString *const kTSStorageManager_AccountLastNames = @"kTSStorageManager_Account
         return self;
     }
 
+    // TODO: We need to configure the limits of this cache.
     _avatarCache = [NSCache new];
     _allContacts = @[];
     _signalAccountMap = @{};

Signal/src/util/ThreadUtil.h

@@ -16,7 +16,25 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface ThreadOffersAndIndicators : NSObject
 
-@property (nonatomic, nullable) TSUnreadIndicatorInteraction *unreadIndicator;
+// If there are unseen messages in the thread, this is the index
+// of the unseen indicator, counting from the _end_ of the conversation
+// history.
+//
+// This is used by MessageViewController to increase the
+// range size of the mappings (the load window of the conversation)
+// to include the unread indicator.
+@property (nonatomic, nullable) NSNumber *unreadIndicatorPosition;
+
+// If there are unseen messages in the thread, this is the timestamp
+// of the oldest unseen messaage.
+//
+// Once we enter messages view, we mark all messages read, so we need
+// a snapshot of what the first unread message was when we entered the
+// view so that we can call ensureThreadOffersAndIndicators:...
+// repeatedly. The unread indicator should continue to show up until
+// it has been cleared, at which point hideUnreadMessagesIndicator is
+// YES in ensureThreadOffersAndIndicators:...
+@property (nonatomic, nullable) NSNumber *firstUnseenInteractionTimestamp;
 
 @end
 
@@ -33,17 +51,30 @@ NS_ASSUME_NONNULL_BEGIN
                     messageSender:(OWSMessageSender *)messageSender;
 
 // This method will create and/or remove any offers and indicators
-// necessary for this thread.
+// necessary for this thread.  This includes:
+//
+// * Block offers.
+// * "Add to contacts" offers.
+// * Unread indicators.
+//
+// Parameters:
 //
-// * If hideUnreadMessagesIndicator is YES, there will be no "unread indicator".
-// * Otherwise, if fixedUnreadIndicatorTimestamp is non-null, there will be a "unread indicator".
-// * Otherwise, there will be a "unread indicator" if there is one unread message.
+// * hideUnreadMessagesIndicator: If YES, the "unread indicator" has
+//   been cleared and should not be shown.
+// * firstUnseenInteractionTimestamp: A snapshot of unseen message state
+//   when we entered the conversation view.  See comments on
+//   ThreadOffersAndIndicators.
+// * maxRangeSize: Loading a lot of messages in conversation view is
+//   slow and unwieldy.  This number represents the maximum current
+//   size of the "load window" in that view. The unread indicator should
+//   always be inserted within that window.
 + (ThreadOffersAndIndicators *)ensureThreadOffersAndIndicators:(TSThread *)thread
                                                 storageManager:(TSStorageManager *)storageManager
                                                contactsManager:(OWSContactsManager *)contactsManager
                                                blockingManager:(OWSBlockingManager *)blockingManager
                                    hideUnreadMessagesIndicator:(BOOL)hideUnreadMessagesIndicator
-                                 fixedUnreadIndicatorTimestamp:(NSNumber *_Nullable)fixedUnreadIndicatorTimestamp;
+                               firstUnseenInteractionTimestamp:(nullable NSNumber *)firstUnseenInteractionTimestamp
+                                                  maxRangeSize:(int)maxRangeSize;
 
 @end
 

Signal/src/util/ThreadUtil.m

@@ -86,27 +86,27 @@ NS_ASSUME_NONNULL_BEGIN
                                                contactsManager:(OWSContactsManager *)contactsManager
                                                blockingManager:(OWSBlockingManager *)blockingManager
                                    hideUnreadMessagesIndicator:(BOOL)hideUnreadMessagesIndicator
-                                 fixedUnreadIndicatorTimestamp:(NSNumber *_Nullable)fixedUnreadIndicatorTimestamp
+                               firstUnseenInteractionTimestamp:
+                                   (nullable NSNumber *)firstUnseenInteractionTimestampParameter
+                                                  maxRangeSize:(int)maxRangeSize
 {
     OWSAssert(thread);
     OWSAssert(storageManager);
     OWSAssert(contactsManager);
     OWSAssert(blockingManager);
+    OWSAssert(maxRangeSize > 0);
 
     ThreadOffersAndIndicators *result = [ThreadOffersAndIndicators new];
 
     [storageManager.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
         const int kMaxBlockOfferOutgoingMessageCount = 10;
 
+        // Find any existing "dynamic" interactions.
         __block OWSAddToContactsOfferMessage *existingAddToContactsOffer = nil;
         __block OWSUnknownContactBlockOfferMessage *existingBlockOffer = nil;
         __block TSUnreadIndicatorInteraction *existingUnreadIndicator = nil;
-        __block TSIncomingMessage *firstIncomingMessage = nil;
-        __block TSOutgoingMessage *firstOutgoingMessage = nil;
-        __block TSIncomingMessage *firstUnreadMessage = nil;
-        __block long outgoingMessageCount = 0;
-
-        [[transaction ext:TSMessageDatabaseViewExtensionName]
+        // We use different views for performance reasons.
+        [[transaction ext:TSDynamicMessagesDatabaseViewExtensionName]
             enumerateRowsInGroup:thread.uniqueId
                       usingBlock:^(
                           NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
@@ -120,43 +120,171 @@ NS_ASSUME_NONNULL_BEGIN
                           } else if ([object isKindOfClass:[TSUnreadIndicatorInteraction class]]) {
                               OWSAssert(!existingUnreadIndicator);
                               existingUnreadIndicator = (TSUnreadIndicatorInteraction *)object;
-                          } else if ([object isKindOfClass:[TSIncomingMessage class]]) {
+                          } else {
+                              DDLogError(@"Unexpected dynamic interaction type: %@", [object class]);
+                              OWSAssert(0);
+                          }
+                      }];
+
+        // Find any existing safety number changes.
+        //
+        // We use different views for performance reasons.
+        NSMutableArray<TSInvalidIdentityKeyErrorMessage *> *blockingSafetyNumberChanges = [NSMutableArray new];
+        NSMutableArray<TSInteraction *> *nonBlockingSafetyNumberChanges = [NSMutableArray new];
+        [[transaction ext:TSSafetyNumberChangeDatabaseViewExtensionName]
+            enumerateRowsInGroup:thread.uniqueId
+                      usingBlock:^(
+                          NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
+
+                          if ([object isKindOfClass:[TSInvalidIdentityKeyErrorMessage class]]) {
+                              [blockingSafetyNumberChanges addObject:object];
+                          } else if ([object isKindOfClass:[TSErrorMessage class]]) {
+                              TSErrorMessage *errorMessage = (TSErrorMessage *)object;
+                              OWSAssert(errorMessage.errorType == TSErrorMessageNonBlockingIdentityChange);
+                              [nonBlockingSafetyNumberChanges addObject:object];
+                          } else {
+                              DDLogError(@"Unexpected interaction type: %@", [object class]);
+                              OWSAssert(0);
+                          }
+                      }];
+
+        // Determine if there are "unread" messages in this conversation.
+        // If we've been passed a firstUnseenInteractionTimestampParameter,
+        // just use that value in order to preserve continuity of the
+        // unread messages indicator after all messages in the conversation
+        // have been marked as read.
+        //
+        // IFF this variable is non-null, there are unseen messages in the thread.
+        __block NSNumber *firstUnseenInteractionTimestamp = nil;
+        if (firstUnseenInteractionTimestampParameter) {
+            firstUnseenInteractionTimestamp = firstUnseenInteractionTimestampParameter;
+        } else {
+            TSInteraction *firstUnseenInteraction =
+                [[transaction ext:TSUnseenDatabaseViewExtensionName] firstObjectInGroup:thread.uniqueId];
+            if (firstUnseenInteraction) {
+                firstUnseenInteractionTimestamp = @(firstUnseenInteraction.timestampForSorting);
+            }
+        }
+
+        __block TSIncomingMessage *firstIncomingMessage = nil;
+        __block TSOutgoingMessage *firstOutgoingMessage = nil;
+        __block long outgoingMessageCount = 0;
+        [[transaction ext:TSMessageDatabaseViewExtensionName]
+            enumerateRowsInGroup:thread.uniqueId
+                      usingBlock:^(
+                          NSString *collection, NSString *key, id object, id metadata, NSUInteger index, BOOL *stop) {
+
+                          if ([object isKindOfClass:[TSIncomingMessage class]]) {
                               TSIncomingMessage *incomingMessage = (TSIncomingMessage *)object;
                               if (!firstIncomingMessage) {
                                   firstIncomingMessage = incomingMessage;
                               } else {
-                                  OWSAssert([[firstIncomingMessage receiptDateForSorting]
-                                                compare:[incomingMessage receiptDateForSorting]]
-                                      == NSOrderedAscending);
-                              }
-
-                              if (!incomingMessage.wasRead) {
-                                  if (!firstUnreadMessage) {
-                                      firstUnreadMessage = incomingMessage;
-                                  } else {
-                                      OWSAssert([[firstUnreadMessage receiptDateForSorting]
-                                                    compare:[incomingMessage receiptDateForSorting]]
-                                          == NSOrderedAscending);
-                                  }
+                                  OWSAssert(
+                                      [firstIncomingMessage compareForSorting:incomingMessage] == NSOrderedAscending);
                               }
                           } else if ([object isKindOfClass:[TSOutgoingMessage class]]) {
                               TSOutgoingMessage *outgoingMessage = (TSOutgoingMessage *)object;
                               if (!firstOutgoingMessage) {
                                   firstOutgoingMessage = outgoingMessage;
                               } else {
-                                  OWSAssert([[firstOutgoingMessage receiptDateForSorting]
-                                                compare:[outgoingMessage receiptDateForSorting]]
-                                      == NSOrderedAscending);
+                                  OWSAssert(
+                                      [firstOutgoingMessage compareForSorting:outgoingMessage] == NSOrderedAscending);
                               }
                               outgoingMessageCount++;
+                              if (outgoingMessageCount >= kMaxBlockOfferOutgoingMessageCount) {
+                                  *stop = YES;
+                              }
                           }
                       }];
 
+
+        // Enumerate in reverse to count the number of messages
+        // after the unseen messages indicator.  Not all of
+        // them are unnecessarily unread, but we need to tell
+        // the messages view the position of the unread indicator,
+        // so that it can widen its "load window" to always show
+        // the unread indicator.
+        __block long visibleUnseenMessageCount = 0;
+        __block BOOL hasMoreUnseenMessages = NO;
+        __block TSInteraction *interactionAfterUnreadIndicator = nil;
+        NSUInteger missingUnseenSafetyNumberChangeCount = 0;
+        if (firstUnseenInteractionTimestamp) {
+            [[transaction ext:TSMessageDatabaseViewExtensionName]
+                enumerateRowsInGroup:thread.uniqueId
+                         withOptions:NSEnumerationReverse
+                          usingBlock:^(NSString *collection,
+                              NSString *key,
+                              id object,
+                              id metadata,
+                              NSUInteger index,
+                              BOOL *stop) {
+
+                              if (![object isKindOfClass:[TSInteraction class]]) {
+                                  OWSFail(@"Expected a TSInteraction");
+                                  return;
+                              }
+
+                              if ([object isKindOfClass:[TSUnreadIndicatorInteraction class]]) {
+                                  // Ignore existing unread indicator, if any.
+                                  return;
+                              }
+
+                              TSInteraction *interaction = (TSInteraction *)object;
+
+                              if (interaction.timestampForSorting
+                                  < firstUnseenInteractionTimestamp.unsignedLongLongValue) {
+                                  // By default we want the unread indicator to appear just before
+                                  // the first unread message.
+                                  *stop = YES;
+                                  return;
+                              }
+
+                              visibleUnseenMessageCount++;
+
+                              interactionAfterUnreadIndicator = interaction;
+
+                              if (visibleUnseenMessageCount + 1 >= maxRangeSize) {
+                                  // If there are more unseen messages than can be displayed in the
+                                  // messages view, show the unread indicator at the top of the
+                                  // displayed messages.
+                                  *stop = YES;
+                                  hasMoreUnseenMessages = YES;
+                              }
+                          }];
+
+            OWSAssert(interactionAfterUnreadIndicator);
+
+            if (hasMoreUnseenMessages) {
+                NSMutableSet<NSData *> *missingUnseenSafetyNumberChanges = [NSMutableSet set];
+                for (TSInvalidIdentityKeyErrorMessage *safetyNumberChange in blockingSafetyNumberChanges) {
+                    BOOL isUnseen = safetyNumberChange.timestampForSorting
+                        >= firstUnseenInteractionTimestamp.unsignedLongLongValue;
+                    if (!isUnseen) {
+                        continue;
+                    }
+                    BOOL isMissing
+                        = safetyNumberChange.timestampForSorting < interactionAfterUnreadIndicator.timestampForSorting;
+                    if (!isMissing) {
+                        continue;
+                    }
+                    [missingUnseenSafetyNumberChanges addObject:safetyNumberChange.newIdentityKey];
+                }
+
+                // Count the de-duplicated "blocking" safety number changes and all
+                // of the "non-blocking" safety number changes.
+                missingUnseenSafetyNumberChangeCount
+                    = (missingUnseenSafetyNumberChanges.count + nonBlockingSafetyNumberChanges.count);
+            }
+        }
+        result.firstUnseenInteractionTimestamp = firstUnseenInteractionTimestamp;
+        if (hasMoreUnseenMessages) {
+            // The unread indicator is _before_ the last visible unseen message.
+            result.unreadIndicatorPosition = @(visibleUnseenMessageCount);
+        }
+
         TSMessage *firstMessage = firstIncomingMessage;
         if (!firstMessage
-            || (firstOutgoingMessage &&
-                   [[firstOutgoingMessage receiptDateForSorting] compare:[firstMessage receiptDateForSorting]]
-                       == NSOrderedAscending)) {
+            || (firstOutgoingMessage && [firstOutgoingMessage compareForSorting:firstMessage] == NSOrderedAscending)) {
             firstMessage = firstOutgoingMessage;
         }
 
@@ -200,8 +328,7 @@ NS_ASSUME_NONNULL_BEGIN
 
         BOOL hasOutgoingBeforeIncomingInteraction = (firstOutgoingMessage
             && (!firstIncomingMessage ||
-                   [[firstOutgoingMessage receiptDateForSorting] compare:[firstIncomingMessage receiptDateForSorting]]
-                       == NSOrderedAscending));
+                   [firstOutgoingMessage compareForSorting:firstIncomingMessage] == NSOrderedAscending));
         if (hasOutgoingBeforeIncomingInteraction) {
             // If there is an outgoing message before an incoming message
             // the local user initiated this conversation, don't show a block offer.
@@ -214,6 +341,7 @@ NS_ASSUME_NONNULL_BEGIN
         const int kUnreadIndicatorOfferOffset = -1;
 
         if (existingBlockOffer && !shouldHaveBlockOffer) {
+            DDLogInfo(@"Removing block offer");
             [existingBlockOffer removeWithTransaction:transaction];
         } else if (!existingBlockOffer && shouldHaveBlockOffer) {
             DDLogInfo(@"Creating block offer for unknown contact");
@@ -221,7 +349,7 @@ NS_ASSUME_NONNULL_BEGIN
             // We want the block offer to be the first interaction in their
             // conversation's timeline, so we back-date it to slightly before
             // the first incoming message (which we know is the first message).
-            uint64_t blockOfferTimestamp = (uint64_t)((long long)firstMessage.timestamp + kBlockOfferOffset);
+            uint64_t blockOfferTimestamp = (uint64_t)((long long)firstMessage.timestampForSorting + kBlockOfferOffset);
             NSString *recipientId = ((TSContactThread *)thread).contactIdentifier;
 
             TSMessage *offerMessage =
@@ -232,6 +360,7 @@ NS_ASSUME_NONNULL_BEGIN
         }
 
         if (existingAddToContactsOffer && !shouldHaveAddToContactsOffer) {
+            DDLogInfo(@"Removing 'add to contacts' offer");
             [existingAddToContactsOffer removeWithTransaction:transaction];
         } else if (!existingAddToContactsOffer && shouldHaveAddToContactsOffer) {
 
@@ -240,7 +369,8 @@ NS_ASSUME_NONNULL_BEGIN
             // We want the offer to be the first interaction in their
             // conversation's timeline, so we back-date it to slightly before
             // the first incoming message (which we know is the first message).
-            uint64_t offerTimestamp = (uint64_t)((long long)firstMessage.timestamp + kAddToContactsOfferOffset);
+            uint64_t offerTimestamp
+                = (uint64_t)((long long)firstMessage.timestampForSorting + kAddToContactsOfferOffset);
             NSString *recipientId = ((TSContactThread *)thread).contactIdentifier;
 
             TSMessage *offerMessage = [OWSAddToContactsOfferMessage addToContactsOfferMessage:offerTimestamp
@@ -249,37 +379,40 @@ NS_ASSUME_NONNULL_BEGIN
             [offerMessage saveWithTransaction:transaction];
         }
 
-        BOOL shouldHaveUnreadIndicator
-            = ((firstUnreadMessage != nil || fixedUnreadIndicatorTimestamp != nil) && !hideUnreadMessagesIndicator);
+        BOOL shouldHaveUnreadIndicator = (interactionAfterUnreadIndicator && !hideUnreadMessagesIndicator);
         if (!shouldHaveUnreadIndicator) {
             if (existingUnreadIndicator) {
+                DDLogInfo(@"%@ Removing obsolete TSUnreadIndicatorInteraction: %@",
+                    self.tag,
+                    existingUnreadIndicator.uniqueId);
                 [existingUnreadIndicator removeWithTransaction:transaction];
             }
         } else {
-            // We want the block offer to appear just before the first unread incoming
+            // We want the unread indicator to appear just before the first unread incoming
             // message in the conversation timeline...
             //
             // ...unless we have a fixed timestamp for the unread indicator.
-            uint64_t indicatorTimestamp = (uint64_t)(fixedUnreadIndicatorTimestamp
-                    ? [fixedUnreadIndicatorTimestamp longLongValue]
-                    : ((long long)firstUnreadMessage.timestamp + kUnreadIndicatorOfferOffset));
+            uint64_t indicatorTimestamp = (uint64_t)(
+                (long long)interactionAfterUnreadIndicator.timestampForSorting + kUnreadIndicatorOfferOffset);
 
-            if (indicatorTimestamp && existingUnreadIndicator.timestamp == indicatorTimestamp) {
+            if (indicatorTimestamp && existingUnreadIndicator.timestampForSorting == indicatorTimestamp) {
                 // Keep the existing indicator; it is in the correct position.
-
-                result.unreadIndicator = existingUnreadIndicator;
             } else {
                 if (existingUnreadIndicator) {
+                    DDLogInfo(@"%@ Removing TSUnreadIndicatorInteraction due to changed timestamp: %@",
+                        self.tag,
+                        existingUnreadIndicator.uniqueId);
                     [existingUnreadIndicator removeWithTransaction:transaction];
                 }
 
-                DDLogInfo(@"%@ Creating TSUnreadIndicatorInteraction", self.tag);
-
                 TSUnreadIndicatorInteraction *indicator =
-                    [[TSUnreadIndicatorInteraction alloc] initWithTimestamp:indicatorTimestamp thread:thread];
+                    [[TSUnreadIndicatorInteraction alloc] initWithTimestamp:indicatorTimestamp
+                                                                     thread:thread
+                                                      hasMoreUnseenMessages:hasMoreUnseenMessages
+                                       missingUnseenSafetyNumberChangeCount:missingUnseenSafetyNumberChangeCount];
                 [indicator saveWithTransaction:transaction];
 
-                result.unreadIndicator = indicator;
+                DDLogInfo(@"%@ Creating TSUnreadIndicatorInteraction: %@", self.tag, indicator.uniqueId);
             }
         }
     }];

Signal/src/views/OWSExpirableMessageView.h

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 9/29/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -12,7 +13,7 @@ static const CGFloat OWSExpirableMessageViewTimerWidth = 10.0f;
 @property (strong, nonatomic, readonly) IBOutlet OWSExpirationTimerView *expirationTimerView;
 @property (strong, nonatomic, readonly) IBOutlet NSLayoutConstraint *expirationTimerViewWidthConstraint;
 
-- (void)startExpirationTimerWithExpiresAtSeconds:(uint64_t)expiresAtSeconds
+- (void)startExpirationTimerWithExpiresAtSeconds:(double)expiresAtSeconds
                           initialDurationSeconds:(uint32_t)initialDurationSeconds;
 
 - (void)stopExpirationTimer;

Signal/src/views/OWSExpirationTimerView.h

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 9/29/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import <UIKit/UIKit.h>
 
@@ -7,8 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface OWSExpirationTimerView : UIView
 
-- (void)startTimerWithExpiresAtSeconds:(uint64_t)expiresAtSeconds
-                initialDurationSeconds:(uint32_t)initialDurationSeconds;
+- (void)startTimerWithExpiresAtSeconds:(double)expiresAtSeconds initialDurationSeconds:(uint32_t)initialDurationSeconds;
 
 - (void)stopTimer;
 

Signal/src/views/OWSExpirationTimerView.m

@@ -1,5 +1,6 @@
-//  Created by Michael Kirk on 9/29/16.
-//  Copyright © 2016 Open Whisper Systems. All rights reserved.
+//
+//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//
 
 #import "OWSExpirationTimerView.h"
 #import "MessagesViewController.h"
@@ -14,7 +15,7 @@ double const OWSExpirationTimerViewBlinkingSeconds = 2;
 @interface OWSExpirationTimerView ()
 
 @property (nonatomic) uint32_t initialDurationSeconds;
-@property (atomic) uint64_t expiresAtSeconds;
+@property (atomic) double expiresAtSeconds;
 
 @property (nonatomic, readonly) UIImageView *emptyHourglassImageView;
 @property (nonatomic, readonly) UIImageView *fullHourglassImageView;
@@ -91,8 +92,7 @@ double const OWSExpirationTimerViewBlinkingSeconds = 2;
     [self startAnimation];
 }
 
-- (void)startTimerWithExpiresAtSeconds:(uint64_t)expiresAtSeconds
-                initialDurationSeconds:(uint32_t)initialDurationSeconds
+- (void)startTimerWithExpiresAtSeconds:(double)expiresAtSeconds initialDurationSeconds:(uint32_t)initialDurationSeconds
 {
     if (expiresAtSeconds == 0) {
         DDLogWarn(
@@ -101,7 +101,7 @@ double const OWSExpirationTimerViewBlinkingSeconds = 2;
             initialDurationSeconds);
     }
 
-    DDLogVerbose(@"%@ Starting timer with expiresAtSeconds: %llu initialDurationSeconds: %d",
+    DDLogVerbose(@"%@ Starting timer with expiresAtSeconds: %f initialDurationSeconds: %d",
         self.logTag,
         expiresAtSeconds,
         initialDurationSeconds);
@@ -117,12 +117,12 @@ double const OWSExpirationTimerViewBlinkingSeconds = 2;
 
 - (void)startAnimation
 {
-    DDLogVerbose(@"%@ Starting animation with expiresAtSeconds: %llu initialDurationSeconds: %d",
+    DDLogVerbose(@"%@ Starting animation with expiresAtSeconds: %f initialDurationSeconds: %d",
         self.logTag,
         self.expiresAtSeconds,
         self.initialDurationSeconds);
 
-    double secondsLeft = (double)self.expiresAtSeconds - [NSDate new].timeIntervalSince1970;
+    double secondsLeft = self.expiresAtSeconds - [NSDate new].timeIntervalSince1970;
 
     if (secondsLeft < 0) {
         secondsLeft = 0;
@@ -186,7 +186,7 @@ double const OWSExpirationTimerViewBlinkingSeconds = 2;
 
 - (BOOL)itIsTimeToBlink
 {
-    double secondsLeft = (double)self.expiresAtSeconds - [NSDate new].timeIntervalSince1970;
+    double secondsLeft = self.expiresAtSeconds - [NSDate new].timeIntervalSince1970;
     return secondsLeft <= OWSExpirationTimerViewBlinkingSeconds;
 }
 

Signal/src/views/OWSIncomingMessageCollectionViewCell.m

@@ -55,7 +55,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 // pragma mark - OWSExpirableMessageView
 
-- (void)startExpirationTimerWithExpiresAtSeconds:(uint64_t)expiresAtSeconds
+- (void)startExpirationTimerWithExpiresAtSeconds:(double)expiresAtSeconds
                           initialDurationSeconds:(uint32_t)initialDurationSeconds
 {
     self.expirationTimerViewWidthConstraint.constant = OWSExpirableMessageViewTimerWidth;

Signal/src/views/OWSOutgoingMessageCollectionViewCell.m

@@ -61,7 +61,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 // pragma mark - OWSExpirableMessageView
 
-- (void)startExpirationTimerWithExpiresAtSeconds:(uint64_t)expiresAtSeconds
+- (void)startExpirationTimerWithExpiresAtSeconds:(double)expiresAtSeconds
                           initialDurationSeconds:(uint32_t)initialDurationSeconds
 {
     self.expirationTimerViewWidthConstraint.constant = OWSExpirableMessageViewTimerWidth;

Signal/src/views/OWSUnreadIndicatorCell.h

@@ -5,8 +5,15 @@
 #import <JSQMessagesViewController/JSQMessagesCollectionViewCell.h>
 #import <UIKit/UIKit.h>
 
+@class TSUnreadIndicatorInteraction;
+
 @interface OWSUnreadIndicatorCell : JSQMessagesCollectionViewCell
 
+@property (nonatomic) TSUnreadIndicatorInteraction *interaction;
+
 - (void)configure;
 
++ (CGSize)cellSizeForInteraction:(TSUnreadIndicatorInteraction *)interaction
+             collectionViewWidth:(CGFloat)collectionViewWidth;
+
 @end

Signal/src/views/OWSUnreadIndicatorCell.m

@@ -3,7 +3,9 @@
 //
 
 #import "OWSUnreadIndicatorCell.h"
+#import "NSBundle+JSQMessages.h"
 #import "OWSBezierPathView.h"
+#import "TSUnreadIndicatorInteraction.h"
 #import "UIColor+OWS.h"
 #import "UIFont+OWS.h"
 #import "UIView+OWS.h"
@@ -11,7 +13,8 @@
 
 @interface OWSUnreadIndicatorCell ()
 
-@property (nonatomic) UILabel *label;
+@property (nonatomic) UILabel *titleLabel;
+@property (nonatomic) UILabel *subtitleLabel;
 @property (nonatomic) OWSBezierPathView *leftPathView;
 @property (nonatomic) OWSBezierPathView *rightPathView;
 
@@ -30,13 +33,21 @@
 {
     self.backgroundColor = [UIColor whiteColor];
 
-    if (!self.label) {
-        self.label = [UILabel new];
-        self.label.text = NSLocalizedString(
-            @"MESSAGES_VIEW_UNREAD_INDICATOR", @"Indicator that separates read from unread messages.");
-        self.label.textColor = [UIColor ows_infoMessageBorderColor];
-        self.label.font = [UIFont ows_mediumFontWithSize:12.f];
-        [self.contentView addSubview:self.label];
+    if (!self.titleLabel) {
+        self.titleLabel = [UILabel new];
+        self.titleLabel.text = [OWSUnreadIndicatorCell titleForInteraction:self.interaction];
+        self.titleLabel.textColor = [UIColor ows_infoMessageBorderColor];
+        self.titleLabel.font = [OWSUnreadIndicatorCell textFont];
+        [self.contentView addSubview:self.titleLabel];
+
+        self.subtitleLabel = [UILabel new];
+        self.subtitleLabel.text = [OWSUnreadIndicatorCell subtitleForInteraction:self.interaction];
+        self.subtitleLabel.textColor = [UIColor ows_infoMessageBorderColor];
+        self.subtitleLabel.font = [OWSUnreadIndicatorCell textFont];
+        self.subtitleLabel.numberOfLines = 0;
+        self.subtitleLabel.lineBreakMode = NSLineBreakByWordWrapping;
+        self.subtitleLabel.textAlignment = NSTextAlignmentCenter;
+        [self.contentView addSubview:self.subtitleLabel];
 
         CGFloat kLineThickness = 0.5f;
         CGFloat kLineMargin = 5.f;
@@ -61,14 +72,106 @@
     }
 }
 
++ (UIFont *)textFont
+{
+    return [UIFont ows_mediumFontWithSize:12.f];
+}
+
++ (NSString *)titleForInteraction:(TSUnreadIndicatorInteraction *)interaction
+{
+    return NSLocalizedString(@"MESSAGES_VIEW_UNREAD_INDICATOR", @"Indicator that separates read from unread messages.");
+}
+
++ (NSString *)subtitleForInteraction:(TSUnreadIndicatorInteraction *)interaction
+{
+    if (!interaction.hasMoreUnseenMessages) {
+        return nil;
+    }
+    NSString *subtitleFormat = (interaction.missingUnseenSafetyNumberChangeCount > 0
+            ? NSLocalizedString(@"MESSAGES_VIEW_UNREAD_INDICATOR_HAS_MORE_UNSEEN_MESSAGES_FORMAT",
+                  @"Messages that indicates that there are more unseen messages that be revealed by tapping the 'load "
+                  @"earlier messages' button. Embeds {{the name of the 'load earlier messages' button}}")
+            : NSLocalizedString(
+                  @"MESSAGES_VIEW_UNREAD_INDICATOR_HAS_MORE_UNSEEN_MESSAGES_AND_SAFETY_NUMBER_CHANGES_FORMAT",
+                  @"Messages that indicates that there are more unseen messages including safety number changes that "
+                  @"be revealed by tapping the 'load earlier messages' button. Embeds {{the name of the 'load earlier "
+                  @"messages' button}}."));
+    NSString *loadMoreButtonName = [NSBundle jsq_localizedStringForKey:@"load_earlier_messages"];
+    return [NSString stringWithFormat:subtitleFormat, loadMoreButtonName];
+}
+
++ (CGFloat)subtitleHMargin
+{
+    return 20.f;
+}
+
++ (CGFloat)subtitleVSpacing
+{
+    return 3.f;
+}
+
++ (CGFloat)vMargin
+{
+    return 5.f;
+}
+
 - (void)layoutSubviews
 {
     [super layoutSubviews];
 
-    [self.label sizeToFit];
-    [self.label centerOnSuperview];
-    self.leftPathView.frame = CGRectMake(0, 0, self.label.left, self.height);
-    self.rightPathView.frame = CGRectMake(self.label.right, 0, self.width - self.label.right, self.height);
+    [self.titleLabel sizeToFit];
+    if (self.subtitleLabel.text.length < 1) {
+        [self.titleLabel centerOnSuperview];
+    } else {
+        CGSize subtitleSize = [self.subtitleLabel
+            sizeThatFits:CGSizeMake(
+                             self.contentView.width - [OWSUnreadIndicatorCell subtitleHMargin] * 2.f, CGFLOAT_MAX)];
+        CGFloat contentHeight
+            = ceil(self.titleLabel.height) + OWSUnreadIndicatorCell.subtitleVSpacing + ceil(subtitleSize.height);
+
+        self.titleLabel.frame = CGRectMake(round((self.titleLabel.superview.width - self.titleLabel.width) * 0.5f),
+            round((self.titleLabel.superview.height - contentHeight) * 0.5f),
+            ceil(self.titleLabel.width),
+            ceil(self.titleLabel.height));
+        self.subtitleLabel.frame = CGRectMake(round((self.titleLabel.superview.width - subtitleSize.width) * 0.5f),
+            round(self.titleLabel.bottom + OWSUnreadIndicatorCell.subtitleVSpacing),
+            ceil(subtitleSize.width),
+            ceil(subtitleSize.height));
+    }
+
+    self.leftPathView.frame = CGRectMake(0, self.titleLabel.top, self.titleLabel.left, self.titleLabel.height);
+    self.rightPathView.frame = CGRectMake(
+        self.titleLabel.right, self.titleLabel.top, self.width - self.titleLabel.right, self.titleLabel.height);
+}
+
++ (CGSize)cellSizeForInteraction:(TSUnreadIndicatorInteraction *)interaction
+             collectionViewWidth:(CGFloat)collectionViewWidth
+{
+    CGSize result = CGSizeMake(collectionViewWidth, 0);
+    result.height += self.vMargin * 2.f;
+
+    NSString *title = [self titleForInteraction:interaction];
+    NSString *subtitle = [self subtitleForInteraction:interaction];
+
+    // Creating a UILabel to measure the layout is expensive, but it's the only
+    // reliable way to do it.  Unread indicators should be rare, so this is acceptable.
+    UILabel *label = [UILabel new];
+    label.font = [self textFont];
+    label.text = title;
+    result.height += ceil([label sizeThatFits:CGSizeZero].height);
+
+    if (subtitle.length > 0) {
+        result.height += self.subtitleVSpacing;
+
+        label.text = subtitle;
+        // The subtitle may wrap to a second line.
+        label.lineBreakMode = NSLineBreakByWordWrapping;
+        label.numberOfLines = 0;
+        result.height += ceil(
+            [label sizeThatFits:CGSizeMake(collectionViewWidth - self.subtitleHMargin * 2.f, CGFLOAT_MAX)].height);
+    }
+
+    return result;
 }
 
 @end

Signal/src/views/TSUnreadIndicatorInteraction.h

@@ -8,9 +8,16 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface TSUnreadIndicatorInteraction : TSMessage
 
+@property (atomic, readonly) BOOL hasMoreUnseenMessages;
+
+@property (atomic, readonly) NSUInteger missingUnseenSafetyNumberChangeCount;
+
 - (instancetype)initWithCoder:(NSCoder *)coder NS_DESIGNATED_INITIALIZER;
 
-- (instancetype)initWithTimestamp:(uint64_t)timestamp thread:(TSThread *)thread NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithTimestamp:(uint64_t)timestamp
+                                  thread:(TSThread *)thread
+                   hasMoreUnseenMessages:(BOOL)hasMoreUnseenMessages
+    missingUnseenSafetyNumberChangeCount:(NSUInteger)missingUnseenSafetyNumberChangeCount NS_DESIGNATED_INITIALIZER;
 
 @end
 

Signal/src/views/TSUnreadIndicatorInteraction.m

@@ -6,6 +6,15 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+@interface TSUnreadIndicatorInteraction ()
+
+@property (atomic) BOOL hasMoreUnseenMessages;
+
+- (instancetype)initWithTimestamp:(uint64_t)timestamp thread:(TSThread *)thread NS_DESIGNATED_INITIALIZER;
+
+@end
+
+
 @implementation TSUnreadIndicatorInteraction
 
 - (instancetype)initWithCoder:(NSCoder *)coder
@@ -13,7 +22,10 @@ NS_ASSUME_NONNULL_BEGIN
     return [super initWithCoder:coder];
 }
 
-- (instancetype)initWithTimestamp:(uint64_t)timestamp thread:(TSThread *)thread
+- (instancetype)initWithTimestamp:(uint64_t)timestamp
+                                  thread:(TSThread *)thread
+                   hasMoreUnseenMessages:(BOOL)hasMoreUnseenMessages
+    missingUnseenSafetyNumberChangeCount:(NSUInteger)missingUnseenSafetyNumberChangeCount
 {
     self = [super initWithTimestamp:timestamp
                            inThread:thread
@@ -26,17 +38,22 @@ NS_ASSUME_NONNULL_BEGIN
         return self;
     }
 
+    _hasMoreUnseenMessages = hasMoreUnseenMessages;
+    _missingUnseenSafetyNumberChangeCount = missingUnseenSafetyNumberChangeCount;
+
     return self;
 }
 
-- (nullable NSDate *)receiptDateForSorting
+- (BOOL)shouldUseReceiptDateForSorting
+{
+    // Use the timestamp, not the "received at" timestamp to sort,
+    // since we're creating these interactions after the fact and back-dating them.
+    return NO;
+}
+
+- (BOOL)isDynamicInteraction
 {
-    // Always use date, since we're creating these interactions after the fact
-    // and back-dating them.
-    //
-    // By default [TSMessage receiptDateForSorting] will prefer to use receivedAtDate
-    // which is not back-dated.
-    return self.date;
+    return YES;
 }
 
 @end

Signal/translations/en.lproj/Localizable.strings

@@ -670,6 +670,9 @@
 /* table cell label in conversation settings */
 "LIST_GROUP_MEMBERS_ACTION" = "List Group Members";
 
+/* No comment provided by engineer. */
+"load_earlier_messages" = "load_earlier_messages";
+
 /* No comment provided by engineer. */
 "LOGGING_SECTION" = "Logging";
 
@@ -721,6 +724,12 @@
 /* Indicator that separates read from unread messages. */
 "MESSAGES_VIEW_UNREAD_INDICATOR" = "Unread Messages";
 
+/* Messages that indicates that there are more unseen messages including safety number changes that be revealed by tapping the 'load earlier messages' button. Embeds {{the name of the 'load earlier messages' button}}. */
+"MESSAGES_VIEW_UNREAD_INDICATOR_HAS_MORE_UNSEEN_MESSAGES_AND_SAFETY_NUMBER_CHANGES_FORMAT" = "There are more unread messages (including safety number changes) above. Tap \"%@\" to see them.";
+
+/* Messages that indicates that there are more unseen messages that be revealed by tapping the 'load earlier messages' button. Embeds {{the name of the 'load earlier messages' button}} */
+"MESSAGES_VIEW_UNREAD_INDICATOR_HAS_MORE_UNSEEN_MESSAGES_FORMAT" = "There are more unread messages above. Tap \"%@\" to see them.";
+
 /* {{number of minutes}} embedded in strings, e.g. 'Alice updated disappearing messages expiration to {{5 minutes}}'. See other *_TIME_AMOUNT strings */
 "MINUTES_TIME_AMOUNT" = "%u minutes";