Sketch out "typing indicators" interaction and cell.

Signal.xcodeproj/project.pbxproj

@@ -217,6 +217,8 @@
 		34B3F8851E8DF1700035BE1A /* NewGroupViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 34B3F8551E8DF1700035BE1A /* NewGroupViewController.m */; };
 		34B3F8931E8DF1710035BE1A /* SignalsNavigationController.m in Sources */ = {isa = PBXBuildFile; fileRef = 34B3F86E1E8DF1700035BE1A /* SignalsNavigationController.m */; };
 		34B6A903218B3F63007C4606 /* TypingIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34B6A902218B3F62007C4606 /* TypingIndicatorView.swift */; };
+		34B6A905218B4C91007C4606 /* TypingIndicatorInteraction.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34B6A904218B4C90007C4606 /* TypingIndicatorInteraction.swift */; };
+		34B6A907218B5241007C4606 /* TypingIndicatorCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34B6A906218B5240007C4606 /* TypingIndicatorCell.swift */; };
 		34B6D27420F664C900765BE2 /* OWSUnreadIndicator.h in Headers */ = {isa = PBXBuildFile; fileRef = 34B6D27220F664C800765BE2 /* OWSUnreadIndicator.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		34B6D27520F664C900765BE2 /* OWSUnreadIndicator.m in Sources */ = {isa = PBXBuildFile; fileRef = 34B6D27320F664C800765BE2 /* OWSUnreadIndicator.m */; };
 		34BECE2B1F74C12700D7438D /* DebugUIStress.m in Sources */ = {isa = PBXBuildFile; fileRef = 34BECE2A1F74C12700D7438D /* DebugUIStress.m */; };
@@ -868,6 +870,8 @@
 		34B3F86D1E8DF1700035BE1A /* SignalsNavigationController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SignalsNavigationController.h; sourceTree = "<group>"; };
 		34B3F86E1E8DF1700035BE1A /* SignalsNavigationController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SignalsNavigationController.m; sourceTree = "<group>"; };
 		34B6A902218B3F62007C4606 /* TypingIndicatorView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TypingIndicatorView.swift; sourceTree = "<group>"; };
+		34B6A904218B4C90007C4606 /* TypingIndicatorInteraction.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TypingIndicatorInteraction.swift; sourceTree = "<group>"; };
+		34B6A906218B5240007C4606 /* TypingIndicatorCell.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TypingIndicatorCell.swift; sourceTree = "<group>"; };
 		34B6D27220F664C800765BE2 /* OWSUnreadIndicator.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSUnreadIndicator.h; sourceTree = "<group>"; };
 		34B6D27320F664C800765BE2 /* OWSUnreadIndicator.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSUnreadIndicator.m; sourceTree = "<group>"; };
 		34BECE291F74C12700D7438D /* DebugUIStress.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DebugUIStress.h; sourceTree = "<group>"; };
@@ -1575,6 +1579,7 @@
 				34D1F0721F8678AA0066283D /* ConversationViewLayout.m */,
 				341341ED2187467900192D59 /* ConversationViewModel.h */,
 				341341EE2187467900192D59 /* ConversationViewModel.m */,
+				34B6A904218B4C90007C4606 /* TypingIndicatorInteraction.swift */,
 			);
 			path = ConversationView;
 			sourceTree = "<group>";
@@ -1844,6 +1849,7 @@
 				34277A5C20751BDC006049F2 /* OWSQuotedMessageView.m */,
 				34D1F0A51F867BFC0066283D /* OWSSystemMessageCell.h */,
 				34D1F0A61F867BFC0066283D /* OWSSystemMessageCell.m */,
+				34B6A906218B5240007C4606 /* TypingIndicatorCell.swift */,
 			);
 			path = Cells;
 			sourceTree = "<group>";
@@ -3310,6 +3316,7 @@
 				34D99CE4217509C2000AFB39 /* AppEnvironment.swift in Sources */,
 				348570A820F67575004FF32B /* OWSMessageHeaderView.m in Sources */,
 				450DF2091E0DD2C6003D14BE /* UserNotificationsAdaptee.swift in Sources */,
+				34B6A907218B5241007C4606 /* TypingIndicatorCell.swift in Sources */,
 				34D1F0AB1F867BFC0066283D /* OWSContactOffersCell.m in Sources */,
 				340FC8C7204DE64D007AEB0F /* OWSBackupAPI.swift in Sources */,
 				343A65981FC4CFE7000477A1 /* ConversationScrollButton.m in Sources */,
@@ -3388,6 +3395,7 @@
 				34B6A903218B3F63007C4606 /* TypingIndicatorView.swift in Sources */,
 				340FC8D0205BF2FA007AEB0F /* OWSBackupIO.m in Sources */,
 				458E38371D668EBF0094BD24 /* OWSDeviceProvisioningURLParser.m in Sources */,
+				34B6A905218B4C91007C4606 /* TypingIndicatorInteraction.swift in Sources */,
 				4517642B1DE939FD00EDB8B9 /* ContactCell.swift in Sources */,
 				340FC8AB204DAC8D007AEB0F /* DomainFrontingCountryViewController.m in Sources */,
 				3496744D2076768700080B5F /* OWSMessageBubbleView.m in Sources */,

Signal/src/ViewControllers/ConversationView/Cells/TypingIndicatorCell.swift

@@ -0,0 +1,37 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+
+@objc(OWSTypingIndicatorCell)
+public class TypingIndicatorCell: ConversationViewCell {
+
+    @objc
+    public static let cellReuseIdentifier = "TypingIndicatorCell"
+
+        @available(*, unavailable, message:"use other constructor instead.")
+    @objc
+    public required init(coder aDecoder: NSCoder) {
+        notImplemented()
+    }
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+    }
+
+    @objc
+    public override func loadForDisplay() {
+
+    }
+
+    @objc
+    public override func cellSize() -> CGSize {
+        return .zero
+    }
+
+    @objc
+    public override func prepareForReuse() {
+        super.prepareForReuse()
+    }
+}

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -596,6 +596,8 @@ typedef enum : NSUInteger {
 {
     [self.collectionView registerClass:[OWSSystemMessageCell class]
             forCellWithReuseIdentifier:[OWSSystemMessageCell cellReuseIdentifier]];
+    [self.collectionView registerClass:[OWSTypingIndicatorCell class]
+            forCellWithReuseIdentifier:[OWSTypingIndicatorCell cellReuseIdentifier]];
     [self.collectionView registerClass:[OWSContactOffersCell class]
             forCellWithReuseIdentifier:[OWSContactOffersCell cellReuseIdentifier]];
     [self.collectionView registerClass:[OWSMessageCell class]

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -302,6 +302,9 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
             case OWSInteractionType_Offer:
                 measurementCell = [OWSContactOffersCell new];
                 break;
+            case OWSInteractionType_TypingIndicator:
+                measurementCell = [OWSTypingIndicatorCell new];
+                break;
         }
 
         OWSAssertDebug(measurementCell);
@@ -319,6 +322,8 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         return OWSMessageHeaderViewDateHeaderVMargin;
     }
 
+    // TODO:
+
     // "Bubble Collapse".  Adjacent messages with the same author should be close together.
     if (self.interaction.interactionType == OWSInteractionType_IncomingMessage
         && previousLayoutItem.interaction.interactionType == OWSInteractionType_IncomingMessage) {
@@ -359,6 +364,10 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         case OWSInteractionType_Offer:
             return [collectionView dequeueReusableCellWithReuseIdentifier:[OWSContactOffersCell cellReuseIdentifier]
                                                              forIndexPath:indexPath];
+
+        case OWSInteractionType_TypingIndicator:
+            return [collectionView dequeueReusableCellWithReuseIdentifier:[OWSTypingIndicatorCell cellReuseIdentifier]
+                                                             forIndexPath:indexPath];
     }
 }
 
@@ -480,6 +489,7 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
     switch (self.interaction.interactionType) {
         case OWSInteractionType_Unknown:
         case OWSInteractionType_Offer:
+        case OWSInteractionType_TypingIndicator:
             return;
         case OWSInteractionType_Error:
         case OWSInteractionType_Info:

Signal/src/ViewControllers/ConversationView/ConversationViewModel.m

@@ -143,6 +143,7 @@ static const int kYapDatabaseRangeMinLength = 0;
 @property (nonatomic, nullable) ThreadDynamicInteractions *dynamicInteractions;
 @property (nonatomic) BOOL hasClearedUnreadMessagesIndicator;
 @property (nonatomic, nullable) NSDate *collapseCutoffDate;
+@property (nonatomic, nullable) NSString *typingIndicatorsRecipient;
 
 @end
 
@@ -200,6 +201,11 @@ static const int kYapDatabaseRangeMinLength = 0;
     return OWSBlockingManager.sharedManager;
 }
 
+- (id<OWSTypingIndicators>)typingIndicators
+{
+    return SSKEnvironment.shared.typingIndicators;
+}
+
 #pragma mark
 
 - (void)addNotificationListeners
@@ -224,6 +230,10 @@ static const int kYapDatabaseRangeMinLength = 0;
                                              selector:@selector(signalAccountsDidChange:)
                                                  name:OWSContactsManagerSignalAccountsDidChangeNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(typingIndicatorStateDidChange:)
+                                                 name:[OWSTypingIndicatorsImpl typingIndicatorStateDidChange]
+                                               object:nil];
 }
 
 - (void)signalAccountsDidChange:(NSNotification *)notification
@@ -240,6 +250,7 @@ static const int kYapDatabaseRangeMinLength = 0;
     // We need to update the "unread indicator" _before_ we determine the initial range
     // size, since it depends on where the unread indicator is placed.
     self.lastRangeLength = 0;
+    self.typingIndicatorsRecipient = [self.typingIndicators typingIndicatorsForThread:self.thread];
 
     [self ensureDynamicInteractions];
     [self.primaryStorage updateUIDatabaseConnectionToLatest];
@@ -574,6 +585,36 @@ static const int kYapDatabaseRangeMinLength = 0;
                updatedNeighborItemSet:updatedNeighborItemSet];
 }
 
+// A simpler version of the update logic we call when
+// only transient items have changed.
+- (void)updateForTransientItems
+{
+    OWSAssertIsOnMainThread();
+
+    OWSLogVerbose(@"");
+
+    NSMutableArray<NSString *> *oldItemIdList = [NSMutableArray new];
+    for (id<ConversationViewItem> viewItem in self.viewItems) {
+        [oldItemIdList addObject:viewItem.itemId];
+    }
+
+    NSUInteger oldViewItemCount = self.viewItems.count;
+    if (![self reloadViewItems]) {
+        // These errors are rare.
+        OWSFailDebug(@"could not reload view items; hard resetting message mappings.");
+        // resetMappings will call delegate.conversationViewModelDidUpdate.
+        [self resetMappings];
+        return;
+    }
+
+    OWSLogVerbose(@"self.viewItems.count: %zd -> %zd", oldViewItemCount, self.viewItems.count);
+
+    [self updateViewWitholdItemIdList:oldItemIdList
+                       updatedItemSet:[NSSet set]
+                     oldViewItemCount:oldViewItemCount
+               updatedNeighborItemSet:nil];
+}
+
 - (void)updateViewWithOldItemIdList:(NSArray<NSString *> *)oldItemIdList
                      updatedItemSet:(NSSet<NSString *> *)updatedItemSet
              updatedNeighborItemSet:(nullable NSMutableSet<NSString *> *)updatedNeighborItemSet
@@ -863,6 +904,25 @@ static const int kYapDatabaseRangeMinLength = 0;
             OWSAssertDebug(!viewItemCache[interaction.uniqueId]);
             viewItemCache[interaction.uniqueId] = viewItem;
         }
+
+        if (self.typingIndicatorsRecipient) {
+            id<ConversationViewItem> _Nullable lastViewItem = viewItems.lastObject;
+            uint64_t typingIndicatorTimestamp = (lastViewItem ? lastViewItem.interaction.timestamp + 1 : 1);
+            TSInteraction *interaction =
+                [[OWSTypingIndicatorInteraction alloc] initWithThread:self.thread
+                                                            timestamp:typingIndicatorTimestamp
+                                                          recipientId:self.typingIndicatorsRecipient];
+            id<ConversationViewItem> _Nullable viewItem = self.viewItemCache[interaction.uniqueId];
+            if (!viewItem) {
+                viewItem = [[ConversationInteractionViewItem alloc] initWithInteraction:interaction
+                                                                          isGroupThread:isGroupThread
+                                                                            transaction:transaction
+                                                                      conversationStyle:conversationStyle];
+            }
+            [viewItems addObject:viewItem];
+            OWSAssertDebug(!viewItemCache[interaction.uniqueId]);
+            viewItemCache[interaction.uniqueId] = viewItem;
+        }
     }];
 
     // Flag to ensure that we only increment once per launch.
@@ -883,6 +943,7 @@ static const int kYapDatabaseRangeMinLength = 0;
         switch (viewItem.interaction.interactionType) {
             case OWSInteractionType_Unknown:
             case OWSInteractionType_Offer:
+            case OWSInteractionType_TypingIndicator:
                 canShowDate = NO;
                 break;
             case OWSInteractionType_IncomingMessage:
@@ -1276,6 +1337,28 @@ static const int kYapDatabaseRangeMinLength = 0;
     return @(groupIndex);
 }
 
+- (void)typingIndicatorStateDidChange:(NSNotification *)notification
+{
+    OWSAssertIsOnMainThread();
+
+    self.typingIndicatorsRecipient = [self.typingIndicators typingIndicatorsForThread:self.thread];
+}
+
+- (void)setTypingIndicatorsRecipient:(nullable NSString *)typingIndicatorsRecipient
+{
+    OWSAssertIsOnMainThread();
+
+    BOOL didChange = ![NSObject isNullableObject:typingIndicatorsRecipient equalTo:_typingIndicatorsRecipient];
+
+    _typingIndicatorsRecipient = typingIndicatorsRecipient;
+
+    // Update the view items if necessary.
+    // We don't have to do this if they haven't been configured yet.
+    if (didChange && self.viewItems != nil) {
+        [self updateForTransientItems];
+    }
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

Signal/src/ViewControllers/ConversationView/TypingIndicatorInteraction.swift

@@ -0,0 +1,44 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+
+@objc(OWSTypingIndicatorInteraction)
+public class TypingIndicatorInteraction: TSInteraction {
+    @objc
+    public static let TypingIndicatorId = "TypingIndicator"
+
+    @objc
+    public override func isDynamicInteraction() -> Bool {
+        return true
+    }
+
+    @objc
+    public override func interactionType() -> OWSInteractionType {
+        return .typingIndicator
+    }
+
+    @available(*, unavailable, message:"use other constructor instead.")
+    @objc
+    public required init(coder aDecoder: NSCoder) {
+        notImplemented()
+    }
+
+    @available(*, unavailable, message:"use other constructor instead.")
+    @objc
+    public required init(dictionary dictionaryValue: [AnyHashable: Any]!) throws {
+        notImplemented()
+    }
+
+    @objc
+    public let recipientId: String
+
+    @objc
+    public init(thread: TSThread, timestamp: UInt64, recipientId: String) {
+        self.recipientId = recipientId
+
+        super.init(interactionWithUniqueId: TypingIndicatorInteraction.TypingIndicatorId,
+            timestamp: timestamp, in: thread)
+    }
+}

Signal/src/views/TypingIndicatorView.swift

@@ -3,7 +3,9 @@
 //
 
 @objc class TypingIndicatorView: UIStackView {
-    private let kDotMaxHSpacing: CGFloat = 8
+    // This represents the spacing between the dots
+    // _at their max size_.
+    private let kDotMaxHSpacing: CGFloat = 3
 
     @objc
     public static let kMinRadiusPt: CGFloat = 6

SignalServiceKit/src/Messages/Interactions/TSInteraction.h

@@ -16,6 +16,7 @@ typedef NS_ENUM(NSInteger, OWSInteractionType) {
     OWSInteractionType_Call,
     OWSInteractionType_Info,
     OWSInteractionType_Offer,
+    OWSInteractionType_TypingIndicator,
 };
 
 NSString *NSStringFromOWSInteractionType(OWSInteractionType value);
@@ -28,6 +29,9 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value);
 
 @interface TSInteraction : TSYapDatabaseObject
 
+- (instancetype)initInteractionWithUniqueId:(NSString *)uniqueId
+                                  timestamp:(uint64_t)timestamp
+                                   inThread:(TSThread *)thread;
 - (instancetype)initInteractionWithTimestamp:(uint64_t)timestamp inThread:(TSThread *)thread;
 
 @property (nonatomic, readonly) NSString *uniqueThreadId;

SignalServiceKit/src/Messages/Interactions/TSInteraction.m

@@ -27,6 +27,8 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
             return @"OWSInteractionType_Info";
         case OWSInteractionType_Offer:
             return @"OWSInteractionType_Offer";
+        case OWSInteractionType_TypingIndicator:
+            return @"OWSInteractionType_TypingIndicator";
     }
 }
 
@@ -74,6 +76,24 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
     return @"TSInteraction";
 }
 
+- (instancetype)initInteractionWithUniqueId:(NSString *)uniqueId
+                                  timestamp:(uint64_t)timestamp
+                                   inThread:(TSThread *)thread
+{
+    OWSAssertDebug(timestamp > 0);
+
+    self = [super initWithUniqueId:uniqueId];
+
+    if (!self) {
+        return self;
+    }
+
+    _timestamp = timestamp;
+    _uniqueThreadId = thread.uniqueId;
+
+    return self;
+}
+
 - (instancetype)initInteractionWithTimestamp:(uint64_t)timestamp inThread:(TSThread *)thread
 {
     OWSAssertDebug(timestamp > 0);