Fix media gallery cell edge cases.

Signal/src/Models/MessageActions.swift

@@ -99,8 +99,10 @@ class ConversationViewItemActions: NSObject {
         actions.append(replyAction)
 
         if conversationViewItem.hasMediaActionContent {
+            if conversationViewItem.canCopyMedia() {
                 let copyMediaAction = MessageActionBuilder.copyMedia(conversationViewItem: conversationViewItem, delegate: delegate)
                 actions.append(copyMediaAction)
+            }
             if conversationViewItem.canSaveMedia() {
                 let saveMediaAction = MessageActionBuilder.saveMedia(conversationViewItem: conversationViewItem, delegate: delegate)
                 actions.append(saveMediaAction)

Signal/src/ViewControllers/ColorPickerViewController.swift

@@ -394,6 +394,11 @@ private class MockConversationViewItem: NSObject, ConversationViewItem {
         return
     }
 
+    func canCopyMedia() -> Bool {
+        owsFailDebug("unexpected invocation")
+        return false
+    }
+
     func canSaveMedia() -> Bool {
         owsFailDebug("unexpected invocation")
         return false

Signal/src/ViewControllers/ConversationView/ConversationViewItem.h

@@ -135,6 +135,7 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType);
 - (void)saveMediaAction;
 - (void)deleteAction;
 
+- (BOOL)canCopyMedia;
 - (BOOL)canSaveMedia;
 
 // For view items that correspond to interactions, this is the interaction's unique id.

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -877,15 +877,7 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
             break;
         }
         case OWSMessageCellType_MediaGallery: {
-            // AFAIK UIPasteboard only supports "multiple representations
-            // of a single item", not "multiple different items".
-            TSAttachmentStream *_Nullable firstAttachment = self.firstValidGalleryAttachment;
-            if (!firstAttachment) {
-                OWSLogWarn(@"Ignoring copy for gallery without any valid attachments.");
-                return;
-            }
-            //
-            [self copyAttachmentToPasteboard:firstAttachment];
+            OWSFailDebug(@"Can't copy media gallery");
             break;
         }
     }
@@ -947,7 +939,7 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
     }
 }
 
-- (BOOL)canSaveMedia
+- (BOOL)canCopyMedia
 {
     switch (self.messageCellType) {
         case OWSMessageCellType_Unknown:
@@ -963,10 +955,30 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
         case OWSMessageCellType_Video:
             return UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(self.attachmentStream.originalFilePath);
         case OWSMessageCellType_GenericAttachment:
-            return NO;
-        case OWSMessageCellType_DownloadingAttachment: {
+        case OWSMessageCellType_DownloadingAttachment:
+        case OWSMessageCellType_MediaGallery:
             return NO;
     }
+}
+
+- (BOOL)canSaveMedia
+{
+    switch (self.messageCellType) {
+        case OWSMessageCellType_Unknown:
+        case OWSMessageCellType_TextMessage:
+        case OWSMessageCellType_OversizeTextMessage:
+        case OWSMessageCellType_ContactShare:
+            return NO;
+        case OWSMessageCellType_StillImage:
+        case OWSMessageCellType_AnimatedImage:
+            return YES;
+        case OWSMessageCellType_Audio:
+            return NO;
+        case OWSMessageCellType_Video:
+            return UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(self.attachmentStream.originalFilePath);
+        case OWSMessageCellType_GenericAttachment:
+        case OWSMessageCellType_DownloadingAttachment:
+            return NO;
         case OWSMessageCellType_MediaGallery: {
             for (ConversationMediaGalleryItem *mediaGalleryItem in self.mediaGalleryItems) {
                 if (!mediaGalleryItem.attachmentStream) {