Added support for Microsoft Word, Excel & Powerpoint previews

Session/Conversations/ConversationVC+Interaction.swift

@@ -472,7 +472,11 @@ extension ConversationVC : InputViewDelegate, MessageCellDelegate, ContextMenuAc
                     Storage.shared.getContact(with: thread.contactSessionID())?.isTrusted != true {
                     confirmDownload()
                 }
-                else if (viewItem.attachmentStream?.isText == true || viewItem.attachmentStream?.contentType == OWSMimeTypeApplicationPdf), let filePathString: String = viewItem.attachmentStream?.originalFilePath {
+                else if (
+                    viewItem.attachmentStream?.isText == true ||
+                    viewItem.attachmentStream?.isMicrosoftDoc == true ||
+                    viewItem.attachmentStream?.contentType == OWSMimeTypeApplicationPdf
+                ), let filePathString: String = viewItem.attachmentStream?.originalFilePath {
                     let fileUrl: URL = URL(fileURLWithPath: filePathString)
                     let interactionController: UIDocumentInteractionController = UIDocumentInteractionController(url: fileUrl)
                     interactionController.delegate = self

SessionMessagingKit/Sending & Receiving/Attachments/TSAttachment.h

@@ -85,6 +85,7 @@ typedef NS_ENUM(NSUInteger, TSAttachmentType) {
 @property (nonatomic, readonly) BOOL isVoiceMessage;
 @property (nonatomic, readonly) BOOL isVisualMedia;
 @property (nonatomic, readonly) BOOL isText;
+@property (nonatomic, readonly) BOOL isMicrosoftDoc;
 @property (nonatomic, readonly) BOOL isOversizeText;
 
 + (NSString *)emojiForMimeType:(NSString *)contentType;

SessionMessagingKit/Sending & Receiving/Attachments/TSAttachment.m

@@ -241,6 +241,10 @@ NSUInteger const TSAttachmentSchemaVersion = 4;
     return [MIMETypeUtil isText:self.contentType];
 }
 
+- (BOOL)isMicrosoftDoc {
+    return [MIMETypeUtil isMicrosoftDoc:self.contentType];
+}
+
 - (BOOL)isOversizeText
 {
     return [self.contentType isEqualToString:OWSMimeTypeOversizeTextMessage];

SessionUtilitiesKit/Media/MIMETypeUtil.h

@@ -42,6 +42,7 @@ extern NSString *const kSyncMessageFileExtension;
 + (BOOL)isVideo:(NSString *)contentType;
 + (BOOL)isAudio:(NSString *)contentType;
 + (BOOL)isText:(NSString *)contentType;
++ (BOOL)isMicrosoftDoc:(NSString *)contentType;
 + (BOOL)isVisualMedia:(NSString *)contentType;
 
 // filename is optional and should not be trusted.

SessionUtilitiesKit/Media/MIMETypeUtil.m

@@ -290,6 +290,42 @@ NSString *const kSyncMessageFileExtension = @"bin";
     ];
 }
 
++ (BOOL)isMicrosoftDoc:(NSString *)contentType {
+    return [
+        @[
+            // Word files
+            @"application/msword",
+
+            @"application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+            @"application/vnd.openxmlformats-officedocument.wordprocessingml.template",
+            @"application/vnd.ms-word.document.macroEnabled.12",
+            @"application/vnd.ms-word.template.macroEnabled.12",
+
+            // Excel files
+            @"application/vnd.ms-excel",
+
+            @"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+            @"application/vnd.openxmlformats-officedocument.spreadsheetml.template",
+            @"application/vnd.ms-excel.sheet.macroEnabled.12",
+            @"application/vnd.ms-excel.template.macroEnabled.12",
+            @"application/vnd.ms-excel.addin.macroEnabled.12",
+            @"application/vnd.ms-excel.sheet.binary.macroEnabled.12",
+
+            // Powerpoint files
+            @"application/vnd.ms-powerpoint",
+
+            @"application/vnd.openxmlformats-officedocument.presentationml.presentation",
+            @"application/vnd.openxmlformats-officedocument.presentationml.template",
+            @"application/vnd.openxmlformats-officedocument.presentationml.slideshow",
+            @"application/vnd.ms-powerpoint.addin.macroEnabled.12",
+            @"application/vnd.ms-powerpoint.presentation.macroEnabled.12",
+            @"application/vnd.ms-powerpoint.template.macroEnabled.12",
+            @"application/vnd.ms-powerpoint.slideshow.macroEnabled.12"
+        ]
+        containsObject:contentType
+    ];
+}
+
 + (BOOL)isVisualMedia:(NSString *)contentType
 {
     if ([self isImage:contentType]) {