Respond to CR.

// FREEBIE

Signal/src/ViewControllers/ConversationView/MessagesViewController.m

@@ -111,7 +111,8 @@ typedef enum : NSUInteger {
 
 @protocol OWSMessagesCollectionViewFlowLayoutDelegate <NSObject>
 
-- (BOOL)isSpecialItemAtIndexPath:(NSIndexPath *)indexPath;
+// Returns YES for incoming and outgoing text and attachment messages.
+- (BOOL)isUserMessageAtIndexPath:(NSIndexPath *)indexPath;
 
 @end
 
@@ -130,7 +131,7 @@ typedef enum : NSUInteger {
 - (CGSize)sizeForItemAtIndexPath:(NSIndexPath *)indexPath
 {
     // The unread indicator should be sized according to its desired size.
-    if ([self.delegate isSpecialItemAtIndexPath:indexPath]) {
+    if (![self.delegate isUserMessageAtIndexPath:indexPath]) {
         CGSize messageBubbleSize = [self messageBubbleSizeForItemAtIndexPath:indexPath];
         CGFloat finalHeight = messageBubbleSize.height;
         return CGSizeMake(CGRectGetWidth(self.collectionView.frame), ceilf((float)finalHeight));
@@ -1563,8 +1564,7 @@ typedef enum : NSUInteger {
     OWSUnreadIndicatorCell *cell =
         [self.collectionView dequeueReusableCellWithReuseIdentifier:[OWSUnreadIndicatorCell cellReuseIdentifier]
                                                        forIndexPath:indexPath];
-    cell.interaction = unreadIndicator;
+    [cell configureWithInteraction:unreadIndicator];
-    [cell configure];
 
     return cell;
 }
@@ -1577,8 +1577,7 @@ typedef enum : NSUInteger {
     OWSSystemMessageCell *cell =
         [self.collectionView dequeueReusableCellWithReuseIdentifier:[OWSSystemMessageCell cellReuseIdentifier]
                                                        forIndexPath:indexPath];
-    cell.interaction = interaction;
+    [cell configureWithInteraction:interaction];
-    [cell configure];
 
     return cell;
 }
@@ -3825,13 +3824,12 @@ typedef enum : NSUInteger {
 
 #pragma mark - OWSMessagesCollectionViewFlowLayoutDelegate
 
-- (BOOL)isSpecialItemAtIndexPath:(NSIndexPath *)indexPath
+- (BOOL)isUserMessageAtIndexPath:(NSIndexPath *)indexPath;
 {
-    // TODO:
+    // TODO: Eventually it'd be nice to this in a more performant way.
     TSInteraction *interaction = [self interactionAtIndexPath:indexPath];
-    return ([interaction isKindOfClass:[TSUnreadIndicatorInteraction class]] ||
+    return (
-        [interaction isKindOfClass:[TSInfoMessage class]] || [interaction isKindOfClass:[TSErrorMessage class]] ||
+        [interaction isKindOfClass:[TSIncomingMessage class]] || [interaction isKindOfClass:[TSOutgoingMessage class]]);
-        [interaction isKindOfClass:[TSCall class]]);
 }
 
 #pragma mark - Class methods

Signal/src/ViewControllers/DebugUI/DebugUIMessages.m

@@ -42,15 +42,15 @@ NS_ASSUME_NONNULL_BEGIN
                    items:@[
                        [OWSTableItem itemWithTitle:@"Send 10 messages (1/sec.)"
                                        actionBlock:^{
-                                           [DebugUIMessages sendTextMessage:10 thread:thread];
+                                           [DebugUIMessages sendTextMessages:10 thread:thread];
                                        }],
                        [OWSTableItem itemWithTitle:@"Send 100 messages (1/sec.)"
                                        actionBlock:^{
-                                           [DebugUIMessages sendTextMessage:100 thread:thread];
+                                           [DebugUIMessages sendTextMessages:100 thread:thread];
                                        }],
                        [OWSTableItem itemWithTitle:@"Send 1,000 messages (1/sec.)"
                                        actionBlock:^{
-                                           [DebugUIMessages sendTextMessage:1000 thread:thread];
+                                           [DebugUIMessages sendTextMessages:1000 thread:thread];
                                        }],
                        [OWSTableItem itemWithTitle:@"Send text/x-signal-plain"
                                        actionBlock:^{
@@ -146,22 +146,23 @@ NS_ASSUME_NONNULL_BEGIN
 {
     NSArray<NSString *> *randomTexts = @[
         @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. ",
-        @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
+        (@"Lorem ipsum dolor sit amet, consectetur adipiscing elit. "
          @"Suspendisse rutrum, nulla vitae pretium hendrerit, tellus "
-        @"turpis pharetra libero, vitae sodales tortor ante vel sem.",
+         @"turpis pharetra libero, vitae sodales tortor ante vel sem."),
         @"In a time of universal deceit - telling the truth is a revolutionary act.",
         @"If you want a vision of the future, imagine a boot stamping on a human face - forever.",
         @"Who controls the past controls the future. Who controls the present controls the past.",
         @"All animals are equal, but some animals are more equal than others.",
         @"War is peace. Freedom is slavery. Ignorance is strength.",
-        @"All the war-propaganda, all the screaming and lies and hatred, comes invariably from people who are not "
+        (@"All the war-propaganda, all the screaming and lies and hatred, comes invariably from people who are not "
-        @"fighting.",
+         @"fighting."),
-        @"Political language. . . is designed to make lies sound truthful and murder respectable, and to give an "
+        (@"Political language. . . is designed to make lies sound truthful and murder respectable, and to give an "
-        @"appearance of solidity to pure wind.",
+         @"appearance of solidity to pure wind."),
-        @"The nationalist not only does not disapprove of atrocities committed by his own side, but he has a "
+        (@"The nationalist not only does not disapprove of atrocities committed by his own side, but he has a "
-        @"remarkable capacity for not even hearing about them.",
+         @"remarkable capacity for not even hearing about them."),
-        @"Every generation imagines itself to be more intelligent than the one that went before it, and wiser than the "
+        (@"Every generation imagines itself to be more intelligent than the one that went before it, and wiser than "
-        @"one that comes after it.",
+         @"the "
+         @"one that comes after it."),
         @"War against a foreign country only happens when the moneyed classes think they are going to profit from it.",
     ];
     NSString *randomText = randomTexts[(NSUInteger)arc4random_uniform((uint32_t)randomTexts.count)];
@@ -170,14 +171,14 @@ NS_ASSUME_NONNULL_BEGIN
     [ThreadUtil sendMessageWithText:text inThread:thread messageSender:messageSender];
 }
 
-+ (void)sendTextMessage:(int)counter thread:(TSThread *)thread
++ (void)sendTextMessages:(int)counter thread:(TSThread *)thread
 {
     if (counter < 1) {
         return;
     }
     [self sendTextMessageInThread:thread counter:counter];
     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)1.f * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
-        [self sendTextMessage:counter - 1 thread:thread];
+        [self sendTextMessages:counter - 1 thread:thread];
     });
 }
 

Signal/src/views/OWSSystemMessageCell.h

@@ -9,9 +9,9 @@
 
 @interface OWSSystemMessageCell : JSQMessagesCollectionViewCell
 
-@property (nonatomic) TSInteraction *interaction;
+@property (nonatomic, nullable, readonly) TSInteraction *interaction;
 
-- (void)configure;
+- (void)configureWithInteraction:(TSInteraction *)interaction;
 
 + (CGSize)cellSizeForInteraction:(TSInteraction *)interaction collectionViewWidth:(CGFloat)collectionViewWidth;
 

Signal/src/views/OWSSystemMessageCell.m

@@ -15,6 +15,8 @@
 
 @interface OWSSystemMessageCell ()
 
+@property (nonatomic, nullable) TSInteraction *interaction;
+
 @property (nonatomic) UIImageView *imageView;
 @property (nonatomic) UILabel *titleLabel;
 
@@ -29,8 +31,12 @@
     return NSStringFromClass([self class]);
 }
 
-- (void)configure
+- (void)configureWithInteraction:(TSInteraction *)interaction;
 {
+    OWSAssert(interaction);
+
+    _interaction = interaction;
+
     self.backgroundColor = [UIColor whiteColor];
 
     if (!self.titleLabel) {
@@ -72,12 +78,12 @@
 
     if ([interaction isKindOfClass:[TSErrorMessage class]]) {
         switch (((TSErrorMessage *)self.interaction).errorType) {
-            case TSErrorMessageInvalidKeyException:
             case TSErrorMessageNonBlockingIdentityChange:
             case TSErrorMessageWrongTrustedIdentityKey:
-            case TSErrorMessageMissingKeyId:
                 result = [UIImage imageNamed:@"system_message_security"];
                 break;
+            case TSErrorMessageInvalidKeyException:
+            case TSErrorMessageMissingKeyId:
             case TSErrorMessageNoSession:
             case TSErrorMessageInvalidMessage:
             case TSErrorMessageDuplicateMessage:
@@ -89,8 +95,6 @@
     } else if ([interaction isKindOfClass:[TSInfoMessage class]]) {
         switch (((TSInfoMessage *)self.interaction).messageType) {
             case TSInfoMessageUserNotRegistered:
-                result = [UIImage imageNamed:@"system_message_info"];
-                break;
             case TSInfoMessageTypeSessionDidEnd:
             case TSInfoMessageTypeUnsupportedMessage:
             case TSInfoMessageAddToContactsOffer:
@@ -202,4 +206,11 @@
     return result;
 }
 
+- (void)prepareForReuse
+{
+    [super prepareForReuse];
+
+    self.interaction = nil;
+}
+
 @end

Signal/src/views/OWSUnreadIndicatorCell.h

@@ -9,9 +9,10 @@
 
 @interface OWSUnreadIndicatorCell : JSQMessagesCollectionViewCell
 
-@property (nonatomic) TSUnreadIndicatorInteraction *interaction;
+@property (nonatomic, nullable, readonly) TSUnreadIndicatorInteraction *interaction;
 
-- (void)configure;
+- (void)configureWithInteraction:(TSUnreadIndicatorInteraction *)interaction;
+;
 
 + (CGSize)cellSizeForInteraction:(TSUnreadIndicatorInteraction *)interaction
              collectionViewWidth:(CGFloat)collectionViewWidth;

Signal/src/views/OWSUnreadIndicatorCell.m

@@ -12,6 +12,8 @@
 
 @interface OWSUnreadIndicatorCell ()
 
+@property (nonatomic, nullable) TSUnreadIndicatorInteraction *interaction;
+
 @property (nonatomic) UIView *bannerView;
 @property (nonatomic) UIView *bannerTopHighlightView;
 @property (nonatomic) UIView *bannerBottomHighlightView1;
@@ -30,8 +32,12 @@
     return NSStringFromClass([self class]);
 }
 
-- (void)configure
+- (void)configureWithInteraction:(TSUnreadIndicatorInteraction *)interaction;
 {
+    OWSAssert(interaction);
+
+    _interaction = interaction;
+
     self.backgroundColor = [UIColor whiteColor];
 
     if (!self.titleLabel) {
@@ -205,4 +211,11 @@
     return result;
 }
 
+- (void)prepareForReuse
+{
+    [super prepareForReuse];
+
+    self.interaction = nil;
+}
+
 @end