Add ConversationViewModel.

Signal.xcodeproj/project.pbxproj

@@ -41,6 +41,7 @@
 		340FC8CA20517B84007AEB0F /* OWSBackupImportJob.m in Sources */ = {isa = PBXBuildFile; fileRef = 340FC8C820517B84007AEB0F /* OWSBackupImportJob.m */; };
 		340FC8CD20518C77007AEB0F /* OWSBackupJob.m in Sources */ = {isa = PBXBuildFile; fileRef = 340FC8CC20518C76007AEB0F /* OWSBackupJob.m */; };
 		340FC8D0205BF2FA007AEB0F /* OWSBackupIO.m in Sources */ = {isa = PBXBuildFile; fileRef = 340FC8CE205BF2FA007AEB0F /* OWSBackupIO.m */; };
+		341341EF2187467A00192D59 /* ConversationViewModel.m in Sources */ = {isa = PBXBuildFile; fileRef = 341341EE2187467900192D59 /* ConversationViewModel.m */; };
 		341F2C0F1F2B8AE700D07D6B /* DebugUIMisc.m in Sources */ = {isa = PBXBuildFile; fileRef = 341F2C0E1F2B8AE700D07D6B /* DebugUIMisc.m */; };
 		3421981C21061D2E00C57195 /* ByteParserTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3421981B21061D2E00C57195 /* ByteParserTest.swift */; };
 		34277A5E20751BDC006049F2 /* OWSQuotedMessageView.m in Sources */ = {isa = PBXBuildFile; fileRef = 34277A5C20751BDC006049F2 /* OWSQuotedMessageView.m */; };
@@ -651,6 +652,8 @@
 		340FC8CC20518C76007AEB0F /* OWSBackupJob.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSBackupJob.m; sourceTree = "<group>"; };
 		340FC8CE205BF2FA007AEB0F /* OWSBackupIO.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSBackupIO.m; sourceTree = "<group>"; };
 		340FC8CF205BF2FA007AEB0F /* OWSBackupIO.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSBackupIO.h; sourceTree = "<group>"; };
+		341341ED2187467900192D59 /* ConversationViewModel.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ConversationViewModel.h; sourceTree = "<group>"; };
+		341341EE2187467900192D59 /* ConversationViewModel.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ConversationViewModel.m; sourceTree = "<group>"; };
 		341458471FBE11C4005ABCF9 /* fa */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fa; path = translations/fa.lproj/Localizable.strings; sourceTree = "<group>"; };
 		341F2C0D1F2B8AE700D07D6B /* DebugUIMisc.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DebugUIMisc.h; sourceTree = "<group>"; };
 		341F2C0E1F2B8AE700D07D6B /* DebugUIMisc.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DebugUIMisc.m; sourceTree = "<group>"; };
@@ -1566,6 +1569,8 @@
 				34D1F0701F8678AA0066283D /* ConversationViewItem.m */,
 				34D1F0711F8678AA0066283D /* ConversationViewLayout.h */,
 				34D1F0721F8678AA0066283D /* ConversationViewLayout.m */,
+				341341ED2187467900192D59 /* ConversationViewModel.h */,
+				341341EE2187467900192D59 /* ConversationViewModel.m */,
 			);
 			path = ConversationView;
 			sourceTree = "<group>";
@@ -3367,6 +3372,7 @@
 				34D5CCA91EAE3D30005515DB /* AvatarViewHelper.m in Sources */,
 				34D1F0B71F87F8850066283D /* OWSGenericAttachmentView.m in Sources */,
 				34D920E720E179C200D51158 /* OWSMessageFooterView.m in Sources */,
+				341341EF2187467A00192D59 /* ConversationViewModel.m in Sources */,
 				348BB25D20A0C5530047AEC2 /* ContactShareViewHelper.swift in Sources */,
 				34B3F8801E8DF1700035BE1A /* InviteFlow.swift in Sources */,
 				457C87B82032645C008D52D6 /* DebugUINotifications.swift in Sources */,

Signal/src/ViewControllers/ColorPickerViewController.swift

@@ -344,6 +344,10 @@ private class MockConversationViewItem: NSObject, ConversationViewItem {
         super.init()
     }
 
+    func itemId() -> String {
+        return interaction.uniqueId!
+    }
+
     func dequeueCell(for collectionView: UICollectionView, indexPath: IndexPath) -> ConversationViewCell {
         owsFailDebug("unexpected invocation")
         return ConversationViewCell(forAutoLayout: ())

Signal/src/ViewControllers/ConversationView/ConversationViewItem.h

@@ -121,8 +121,14 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType);
 
 - (BOOL)canSaveMedia;
 
+// For view items that correspond to interactions, this is the interaction's unique id.
+// For other view views (like the typing indicator), this is a unique, stable string.
+- (NSString *)itemId;
+
 @end
 
+#pragma mark -
+
 @interface ConversationInteractionViewItem
     : NSObject <ConversationViewItem, ConversationViewLayoutItem, OWSAudioPlayerDelegate>
 

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -153,6 +153,11 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         [TSContactThread conversationColorNameForRecipientId:incomingMessage.authorId transaction:transaction];
 }
 
+- (NSString *)itemId
+{
+    return self.interaction.uniqueId;
+}
+
 - (BOOL)hasBodyText
 {
     return _displayableBodyText != nil;

Signal/src/ViewControllers/ConversationView/ConversationViewModel.h

@@ -0,0 +1,108 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class ConversationStyle;
+@class ConversationViewModel;
+@class OWSQuotedReplyModel;
+@class TSThread;
+@class ThreadDynamicInteractions;
+
+@protocol ConversationViewItem;
+
+typedef NS_ENUM(NSUInteger, ConversationUpdateType) {
+    // No view items in the load window were effected.
+    ConversationUpdateType_Minor,
+    // A subset of view items in the load window were effected;
+    // the view should be updated using the update items.
+    ConversationUpdateType_Diff,
+    // Complicated or unexpected changes occurred in the load window;
+    // the view should be reloaded.
+    ConversationUpdateType_Reload,
+};
+
+#pragma mark -
+
+typedef NS_ENUM(NSUInteger, ConversationUpdateItemType) {
+    ConversationUpdateItemType_Insert,
+    ConversationUpdateItemType_Delete,
+    ConversationUpdateItemType_Update,
+};
+
+#pragma mark -
+
+@interface ConversationUpdateItem : NSObject
+
+@property (nonatomic, readonly) ConversationUpdateItemType updateItemType;
+// Only applies in the "delete" and "update" cases.
+@property (nonatomic, readonly) NSUInteger oldIndex;
+// Only applies in the "insert" and "update" cases.
+@property (nonatomic, readonly) NSUInteger newIndex;
+// Only applies in the "insert" and "update" cases.
+@property (nonatomic, readonly, nullable) id<ConversationViewItem> viewItem;
+
+@end
+
+#pragma mark -
+
+@interface ConversationUpdate : NSObject
+
+@property (nonatomic, readonly) ConversationUpdateType conversationUpdateType;
+// Only applies in the "diff" case.
+@property (nonatomic, readonly, nullable) NSArray<ConversationUpdateItem *> *updateItems;
+//// Only applies in the "diff" case.
+@property (nonatomic, readonly) BOOL shouldAnimateUpdates;
+
+@end
+
+#pragma mark -
+
+@protocol ConversationViewModelDelegate <NSObject>
+
+- (void)conversationViewModelWillUpdate;
+- (void)conversationViewModelDidUpdate:(ConversationUpdate *)conversationUpdate;
+
+- (void)conversationViewModelWillLoadMoreItems;
+- (void)conversationViewModelDidLoadMoreItems;
+- (void)conversationViewModelDidLoadPrevPage;
+- (void)conversationViewModelRangeDidChange;
+
+// TODO: It'd be nice to remove this.
+- (BOOL)shouldObserveDBModifications;
+
+- (ConversationStyle *)conversationStyle;
+
+@end
+
+#pragma mark -
+
+@interface ConversationViewModel : NSObject
+
+@property (nonatomic, readonly) NSArray<id<ConversationViewItem>> *viewItems;
+@property (nonatomic, nullable) NSString *focusMessageIdOnOpen;
+@property (nonatomic, readonly, nullable) ThreadDynamicInteractions *dynamicInteractions;
+
+- (instancetype)init NS_UNAVAILABLE;
+- (instancetype)initWithThread:(TSThread *)thread
+          focusMessageIdOnOpen:(nullable NSString *)focusMessageIdOnOpen
+                      delegate:(id<ConversationViewModelDelegate>)delegate NS_DESIGNATED_INITIALIZER;
+
+- (void)ensureDynamicInteractions;
+
+- (void)clearUnreadMessagesIndicator;
+
+- (void)loadAnotherPageOfMessages;
+
+- (void)viewDidResetContentAndLayout;
+
+- (void)viewDidLoad;
+
+- (BOOL)canLoadMoreItems;
+
+- (nullable NSIndexPath *)ensureLoadWindowContainsQuotedReply:(OWSQuotedReplyModel *)quotedReply;
+
+@end
+
+NS_ASSUME_NONNULL_END