Respond to CR.

// FREEBIE

Signal/src/ViewControllers/ConversationView/Cells/AttachmentUploadView.h

@@ -8,7 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 typedef void (^AttachmentStateBlock)(BOOL isAttachmentReady);
 
-// This entity is used to display download progress for incoming
+// This entity is used to display upload progress for outgoing
 // attachments in conversation view cells.
 //
 // During attachment uploads we want to:

Signal/src/ViewControllers/ConversationView/Cells/OWSMessageCell.m

@@ -92,21 +92,33 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (nullable NSString *)textMessage
 {
+    // This should always be valid for the appropriate cell types.
+    OWSAssert(self.viewItem.textMessage);
+
     return self.viewItem.textMessage;
 }
 
 - (nullable TSAttachmentStream *)attachmentStream
 {
+    // This should always be valid for the appropriate cell types.
+    OWSAssert(self.viewItem.attachmentStream);
+
     return self.viewItem.attachmentStream;
 }
 
 - (nullable TSAttachmentPointer *)attachmentPointer
 {
+    // This should always be valid for the appropriate cell types.
+    OWSAssert(self.viewItem.attachmentPointer);
+
     return self.viewItem.attachmentPointer;
 }
 
 - (CGSize)contentSize
 {
+    // This should always be valid for the appropriate cell types.
+    OWSAssert(self.viewItem.contentSize.width > 0 && self.viewItem.contentSize.height > 0);
+
     return self.viewItem.contentSize;
 }
 
@@ -116,6 +128,8 @@ NS_ASSUME_NONNULL_BEGIN
     OWSAssert(self.viewItem.interaction);
     OWSAssert([self.viewItem.interaction isKindOfClass:[TSMessage class]]);
 
+    DDLogError(@"%p loadForDisplay: %@", self, NSStringForOWSMessageCellType(self.cellType));
+
     BOOL isIncoming = self.isIncoming;
     JSQMessagesBubbleImage *bubbleImageData
         = isIncoming ? [self.bubbleFactory incoming] : [self.bubbleFactory outgoing];
@@ -152,20 +166,6 @@ NS_ASSUME_NONNULL_BEGIN
         }
     }
 
-    // If we have an outgoing attachment and we haven't created a
-    // AttachmentUploadView yet, do so now.
-    //
-    // For some attachment types, we may create this view earlier
-    // so that we can take advantage of its callback.
-    //    if (self.attachmentStream &&
-    //        !self.isIncoming &&
-    //        !self.attachmentUploadView) {
-    //        self.attachmentUploadView = [[AttachmentUploadView alloc] initWithAttachment:self.attachmentStream
-    //                                                                           superview:imageView
-    //                                                             attachmentStateCallback:^(BOOL isAttachmentReady) {
-    //                                                             }];
-    //    }
-
     //    [self.textLabel addBorderWithColor:[UIColor blueColor]];
     //    [self.bubbleImageView addBorderWithColor:[UIColor greenColor]];
 

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.m

@@ -83,7 +83,7 @@ NS_ASSUME_NONNULL_BEGIN
     [self.attachmentButton setImage:[UIImage imageNamed:@"btnAttachments--blue"] forState:UIControlStateNormal];
     [self addSubview:self.attachmentButton];
 
-    // TODO:
+    // TODO: Fix layout in this class.
     _sendButton = [UIButton buttonWithType:UIButtonTypeCustom];
     [self.sendButton
         setTitle:NSLocalizedString(@"SEND_BUTTON_TITLE", @"Label for the send button in the conversation view.")

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -192,7 +192,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 @property (nonatomic, readonly) ContactsViewHelper *contactsViewHelper;
 
 @property (nonatomic) BOOL userHasScrolled;
-@property (nonatomic) NSDate *lastMessageSentDate;
+@property (nonatomic, nullable) NSDate *lastMessageSentDate;
 
 @property (nonatomic, nullable) ThreadDynamicInteractions *dynamicInteractions;
 @property (nonatomic) BOOL hasClearedUnreadMessagesIndicator;
@@ -869,7 +869,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     }
 }
 
-- (void)showUnblockContactUI:(BlockActionCompletionBlock _Nullable)completionBlock
+- (void)showUnblockContactUI:(nullable BlockActionCompletionBlock)completionBlock
 {
     OWSAssert([self.thread isKindOfClass:[TSContactThread class]]);
 
@@ -2747,7 +2747,6 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
         [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
             [self.messageMappings updateWithTransaction:transaction];
         }];
-        [self reloadViewItems];
         return;
     }
 
@@ -2866,13 +2865,6 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 - (BOOL)isScrolledToBottom
 {
     CGFloat contentHeight = self.safeContentHeight;
-    if (contentHeight < 1) {
-        // If the collection view hasn't determined its content size yet,
-        // scroll state is not yet coherent. Therefore we can't (and don't
-        // need to) determine whether we're "scrolled to the bottom" until
-        // the collection view has determined its content size.
-        return NO;
-    }
 
     // This is a bit subtle.
     //
@@ -3069,7 +3061,7 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     self.voiceMessageUUID = nil;
 }
 
-- (void)setAudioRecorder:(AVAudioRecorder *_Nullable)audioRecorder
+- (void)setAudioRecorder:(nullable AVAudioRecorder *)audioRecorder
 {
     // Prevent device from sleeping while recording a voice message.
     if (audioRecorder) {
@@ -3294,15 +3286,13 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 
 - (void)loadDraftInCompose
 {
+    OWSAssert([NSThread isMainThread]);
+
     __block NSString *draft;
-    [self.editingDatabaseConnection asyncReadWithBlock:^(YapDatabaseReadTransaction *transaction) {
+    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
         draft = [_thread currentDraftWithTransaction:transaction];
-    }
-        completionBlock:^{
-            dispatch_async(dispatch_get_main_queue(), ^{
-                [self.inputToolbar setMessageText:draft];
-            });
-        }];
+    }];
+    [self.inputToolbar setMessageText:draft];
 }
 
 - (void)saveDraft
@@ -3468,15 +3458,6 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     BOOL wasAtBottom = [self isScrolledToBottom];
     if (wasAtBottom) {
         [self scrollToBottomImmediately];
-    } else if (self.safeContentHeight < 1) {
-        // If the collection view hasn't determined its content size yet,
-        // scroll state is not yet coherent. Therefore we can't (and don't
-        // need to) determine whether we're "scrolled to the bottom" until
-        // the collection view has determined its content size.
-        //
-        // In this case we should just ensure that scroll state is initialized
-        // properly.
-        [self scrollToDefaultPosition];
     }
 
     [self updateLastVisibleTimestamp];
@@ -3900,10 +3881,9 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
         return;
     }
 
-    // TODO: Recycle view items where possible.
-    // TODO: Distinguish interaction types through some enum.
     [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-        TSInteraction *_Nullable interaction = [TSInteraction fetchObjectWithUniqueID:viewItem.interaction.uniqueId];
+        TSInteraction *_Nullable interaction =
+            [TSInteraction fetchObjectWithUniqueID:viewItem.interaction.uniqueId transaction:transaction];
         if (!interaction) {
             OWSFail(@"%@ could not reload interaction", self.tag);
         } else {
@@ -3915,7 +3895,8 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
 - (nullable ConversationViewItem *)viewItemForIndex:(NSUInteger)index
 {
     if (index >= self.viewItems.count) {
-        OWSFail(@"%@ Invalid view item index: %zd", self.tag, index) return nil;
+        OWSFail(@"%@ Invalid view item index: %zd", self.tag, index);
+        return nil;
     }
     return self.viewItems[index];
 }

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -110,30 +110,26 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
 {
     OWSAssert([NSThread isMainThread]);
 
-    CGSize cellSize = CGSizeZero;
     if (!self.cachedCellSize) {
         ConversationViewCell *_Nullable measurementCell = [self measurementCell];
         measurementCell.viewItem = self;
-        cellSize = [measurementCell cellSizeForViewWidth:viewWidth contentWidth:contentWidth];
+        CGSize cellSize = [measurementCell cellSizeForViewWidth:viewWidth contentWidth:contentWidth];
         self.cachedCellSize = [NSValue valueWithCGSize:cellSize];
         [measurementCell prepareForReuse];
-    } else {
-        cellSize = [self.cachedCellSize CGSizeValue];
     }
-    return cellSize;
+    return [self.cachedCellSize CGSizeValue];
 }
 
 - (ConversationViewLayoutAlignment)layoutAlignment
 {
     switch (self.interaction.interactionType) {
         case OWSInteractionType_Unknown:
+            OWSFail(@"%@ Unknown interaction type: %@", self.tag, self.interaction.debugDescription);
             return ConversationViewLayoutAlignment_Center;
         case OWSInteractionType_IncomingMessage:
             return ConversationViewLayoutAlignment_Incoming;
-            break;
         case OWSInteractionType_OutgoingMessage:
             return ConversationViewLayoutAlignment_Outgoing;
-            break;
         case OWSInteractionType_Error:
         case OWSInteractionType_Info:
         case OWSInteractionType_Call:

Signal/src/ViewControllers/ConversationView/ConversationViewLayout.m

@@ -10,6 +10,7 @@ NS_ASSUME_NONNULL_BEGIN
 @interface ConversationViewLayout ()
 
 @property (nonatomic) CGSize contentSize;
+
 @property (nonatomic, readonly) NSMutableDictionary<NSNumber *, UICollectionViewLayoutAttributes *> *itemAttributesMap;
 
 // This dirty flag may be redundant with logic in UICollectionViewLayout,