Merge branch 'charlesmchen/scrollContinuity4.2'

Signal/src/ViewControllers/ConversationView/CV/CVLoadCoordinator.swift

@@ -542,7 +542,13 @@ public class CVLoadCoordinator: NSObject {
         let (loadPromise, loadResolver) = Promise<Void>.pending()
 
         func canLandLoad() -> Bool {
-            return !delegate.isLayoutApplyingUpdate && !delegate.areCellsAnimating
+            AssertIsOnMainThread()
+            if let lastKeyboardAnimationDate = viewState.lastKeyboardAnimationDate,
+               lastKeyboardAnimationDate.isAfterNow {
+                return false
+            }
+            let result = !delegate.isLayoutApplyingUpdate && !delegate.areCellsAnimating
+            return result
         }
 
         func tryToResolve() {

Signal/src/ViewControllers/ConversationView/CVViewState.swift

@@ -151,6 +151,9 @@ public class CVViewState: NSObject {
     @objc
     public var currentVoiceMessageModel: VoiceMessageModel?
 
+    @objc
+    public var lastKeyboardAnimationDate: Date?
+
     // MARK: - 
 
     @objc

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -3803,11 +3803,26 @@ typedef enum : NSUInteger {
 
 - (void)handleKeyboardStateChange:(NSTimeInterval)animationDuration animationCurve:(UIViewAnimationCurve)animationCurve
 {
+    OWSAssertIsOnMainThread();
+
     if (self.transitionCoordinator.isInteractive) {
         return;
     }
 
     if (self.shouldAnimateKeyboardChanges && animationDuration > 0) {
+        // Make note of when the keyboard animation will block
+        // loads from landing during the keyboard animation.
+        // It isn't safe to block loads for long, so we cap
+        // how long they will be blocked for.
+        NSTimeInterval keyboardAnimationBlockLoadInterval = kSecondInterval * 1.0;
+        NSDate *animationCompletionDate = [[NSDate new] dateByAddingTimeInterval:keyboardAnimationBlockLoadInterval];
+        NSDate *lastKeyboardAnimationDate = [[NSDate new] dateByAddingTimeInterval:-1.0];
+        if (self.viewState.lastKeyboardAnimationDate == nil ||
+            [self.viewState.lastKeyboardAnimationDate isBeforeDate:lastKeyboardAnimationDate]) {
+            self.viewState.lastKeyboardAnimationDate = animationCompletionDate;
+            self.scrollContinuity = ScrollContinuityBottom;
+        }
+
         // The animation curve provided by the keyboard notifications
         // is a private value not represented in UIViewAnimationOptions.
         // We don't use a block based animation here because it's not