cherry-pick (rebased) charlesmchen/stressTesting/Signal/src/ViewControllers/SignalAttachment.swift

// FREEBIE

Signal/src/ViewControllers/SignalAttachment.swift

@@ -589,6 +589,24 @@ class SignalAttachment: NSObject {
                              filename : filename)
     }
 
+    // MARK: Attachments
+
+    // Factory method for attachments of any kind.
+    //
+    // NOTE: The attachment returned by this method may not be valid.
+    //       Check the attachment's error property.
+    public class func attachment(data: Data?, dataUTI: String, filename: String?) -> SignalAttachment {
+        if inputImageUTISet.contains(dataUTI) {
+            return imageAttachment(data : data, dataUTI : dataUTI, filename: filename)
+        } else if videoUTISet.contains(dataUTI) {
+            return videoAttachment(data : data, dataUTI : dataUTI, filename: filename)
+        } else if audioUTISet.contains(dataUTI) {
+            return audioAttachment(data : data, dataUTI : dataUTI, filename: filename)
+        } else {
+            return genericAttachment(data : data, dataUTI : dataUTI, filename: filename)
+        }
+    }
+
     // MARK: Helper Methods
 
     private class func newAttachment(data: Data?,