Show alerts with relevant error messages when attachment-related errors occur.

// FREEBIE

Signal/src/view controllers/MessagesViewController.m

@@ -1951,6 +1951,7 @@ typedef enum : NSUInteger {
                                                        self.tag,
                                                        __PRETTY_FUNCTION__,
                                                        attachment ? [attachment errorMessage] : @"Missing data");
+                                             [self showErrorAlertForAttachment:attachment];
                                              failedToPickAttachment(nil);
                                          } else {
                                              [self sendMessageAttachment:attachment];
@@ -1988,21 +1989,21 @@ typedef enum : NSUInteger {
              
              SignalAttachment *attachment = [SignalAttachment imageAttachmentWithData:imageData
                                                                               dataUTI:dataUTI];
-             if (!attachment ||
-                 [attachment hasError]) {
-                 DDLogWarn(@"%@ %s Invalid attachment: %@.",
-                           self.tag,
-                           __PRETTY_FUNCTION__,
-                           attachment ? [attachment errorMessage] : @"Missing data");
-                 failedToPickAttachment(nil);
-             } else {
-                 [self dismissViewControllerAnimated:YES
-                                          completion:^{
-                                              OWSAssert([NSThread isMainThread]);
-                                              
+             [self dismissViewControllerAnimated:YES
+                                      completion:^{
+                                          OWSAssert([NSThread isMainThread]);
+                                          if (!attachment ||
+                                              [attachment hasError]) {
+                                              DDLogWarn(@"%@ %s Invalid attachment: %@.",
+                                                        self.tag,
+                                                        __PRETTY_FUNCTION__,
+                                                        attachment ? [attachment errorMessage] : @"Missing data");
+                                              [self showErrorAlertForAttachment:attachment];
+                                              failedToPickAttachment(nil);
+                                          } else {
                                               [self sendMessageAttachment:attachment];
-                                          }];
-             }
+                                          }
+                                      }];
          }];
     }
 }
@@ -2083,7 +2084,7 @@ typedef enum : NSUInteger {
                       self.tag,
                       __PRETTY_FUNCTION__,
                       attachment ? [attachment errorMessage] : @"Missing data");
-            // TODO: How should we handle errors here?
+            [self showErrorAlertForAttachment:attachment];
         } else {
             [self sendMessageAttachment:attachment];
         }
@@ -2319,7 +2320,7 @@ typedef enum : NSUInteger {
                       self.tag,
                       __PRETTY_FUNCTION__,
                       attachment ? [attachment errorMessage] : @"Missing data");
-            // TODO: How should we handle errors here?
+            [self showErrorAlertForAttachment:attachment];
         } else {
             [self sendMessageAttachment:attachment];
         }
@@ -2559,13 +2560,13 @@ typedef enum : NSUInteger {
                   self.tag,
                   __PRETTY_FUNCTION__,
                   attachment ? [attachment errorMessage] : @"Missing data");
-        // TODO: Add UI.
+        [self showErrorAlertForAttachment:attachment];
     } else {
         __weak MessagesViewController *weakSelf = self;
         UIViewController *viewController = [[AttachmentApprovalViewController alloc] initWithAttachment:attachment
-                                            successCompletion:^{
-                                                [weakSelf sendMessageAttachment:attachment];
-                                            }];
+                                                                                      successCompletion:^{
+                                                                                          [weakSelf sendMessageAttachment:attachment];
+                                                                                      }];
         UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
         [self.navigationController presentViewController:navigationController
                                                 animated:YES
@@ -2573,6 +2574,30 @@ typedef enum : NSUInteger {
     }
 }
 
+- (void)showErrorAlertForAttachment:(SignalAttachment * _Nullable)attachment {
+    OWSAssert(attachment == nil || [attachment hasError]);
+    
+    NSString *errorMessage = (attachment
+                              ? [attachment errorMessage]
+                              : [SignalAttachment missingDataErrorMessage]);
+    
+    DDLogError(@"%@ %s: %@",
+               self.tag,
+               __PRETTY_FUNCTION__, errorMessage);
+    
+    UIAlertController *controller =
+    [UIAlertController alertControllerWithTitle:NSLocalizedString(@"ATTACHMENT_ERROR_ALERT_TITLE",
+                                                                  @"The title of the 'attachment error' alert.")
+                                        message:errorMessage
+                                 preferredStyle:UIAlertControllerStyleAlert];
+    [controller addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil)
+                                                   style:UIAlertActionStyleDefault
+                                                 handler:nil]];
+    [self presentViewController:controller
+                       animated:YES
+                     completion:nil];
+}
+
 #pragma mark - Class methods
 
 + (UINib *)nib

Signal/src/view controllers/SignalAttachment.swift

@@ -5,7 +5,7 @@
 import Foundation
 import MobileCoreServices
 
-enum SignalAttachmentError: String {
+enum SignalAttachmentError: Int {
     case missingData
     case fileSizeTooLarge
     case invalidData
@@ -97,7 +97,25 @@ class SignalAttachment: NSObject {
             assert(false)
             return nil
         }
-        return "\(error)"
+
+        switch error {
+        case .missingData:
+            return NSLocalizedString("ATTACHMENT_ERROR_MISSING_DATA", comment: "Attachment error message for attachments without any data")
+        case .fileSizeTooLarge:
+            return NSLocalizedString("ATTACHMENT_ERROR_FILE_SIZE_TOO_LARGE", comment: "Attachment error message for attachments whose data exceed file size limits")
+        case .invalidData:
+            return NSLocalizedString("ATTACHMENT_ERROR_INVALID_DATA", comment: "Attachment error message for attachments with invalid data")
+        case .couldNotParseImage:
+            return NSLocalizedString("ATTACHMENT_ERROR_COULD_NOT_PARSE_IMAGE", comment: "Attachment error message for image attachments which cannot be parsed")
+        case .couldNotConvertToJpeg:
+            return NSLocalizedString("ATTACHMENT_ERROR_COULD_NOT_CONVERT_TO_JPEG", comment: "Attachment error message for image attachments which could not be converted to JPEG")
+        case .invalidFileFormat:
+            return NSLocalizedString("ATTACHMENT_ERROR_INVALID_FILE_FORMAT", comment: "Attachment error message for attachments with an invalid file format")
+        }
+    }
+
+    class var missingDataErrorMessage: String {
+        return NSLocalizedString("ATTACHMENT_ERROR_MISSING_DATA", comment: "Attachment error message for attachments without any data")
     }
 
     // Returns the MIME type for this attachment or nil if no MIME type

Signal/translations/en.lproj/Localizable.strings

@@ -67,6 +67,27 @@
 /* No comment provided by engineer. */
 "ATTACHMENT_DOWNLOADING" = "Attachment is downloading";
 
+/* The title of the 'attachment error' alert. */
+"ATTACHMENT_ERROR_ALERT_TITLE" = "Error Sending Attachment";
+
+/* Attachment error message for image attachments which could not be converted to JPEG */
+"ATTACHMENT_ERROR_COULD_NOT_CONVERT_TO_JPEG" = "Image attachment could not be resized.";
+
+/* Attachment error message for image attachments which cannot be parsed */
+"ATTACHMENT_ERROR_COULD_NOT_PARSE_IMAGE" = "Image attachment could not be parsed.";
+
+/* Attachment error message for attachments whose data exceed file size limits */
+"ATTACHMENT_ERROR_FILE_SIZE_TOO_LARGE" = "Attachment is too large.";
+
+/* Attachment error message for attachments with invalid data */
+"ATTACHMENT_ERROR_INVALID_DATA" = "Attachment has invalid contents.";
+
+/* Attachment error message for attachments with an invalid file format */
+"ATTACHMENT_ERROR_INVALID_FILE_FORMAT" = "Attachment has invalid file format.";
+
+/* Attachment error message for attachments without any data */
+"ATTACHMENT_ERROR_MISSING_DATA" = "Attachment is empty.";
+
 /* Accessibility hint describing what you can do with the attachment button */
 "ATTACHMENT_HINT" = "Choose or take a picture and then send it";
 
@@ -79,9 +100,6 @@
 /* No comment provided by engineer. */
 "AUDIO_PERMISSION_MESSAGE" = "Signal requires access to your microphone to work properly. You can grant this permission in the Settings app >> Privacy >> Microphone >> Signal";
 
-/* Title for call interstitial view */
-"CALL_INTERSTITIAL_CALLING_LABEL" = "Calling...";
-
 /* Accessibilty label for placing call button */
 "CALL_LABEL" = "Call";
 
@@ -412,9 +430,6 @@
 /* No comment provided by engineer. */
 "INCOMING_INCOMPLETE_CALL" = "Incomplete incoming call from";
 
-/* Generic error text when message contents are undisplayable */
-"INFO_MESSAGE_UNABLE_TO_DISPLAY_MESSAGE" = "Unable to display message.";
-
 /* Text for button at the top of the contact picker */
 "INVITE_FRIENDS_CONTACT_TABLE_BUTTON" = "Invite Friends to Signal";
 
@@ -934,9 +949,6 @@
 /* No comment provided by engineer. */
 "TXT_DELETE_TITLE" = "Delete";
 
-/* Alert Title */
-"UNABLE_TO_PLACE_CALL" = "Unable to place call.";
-
 /* Pressing this button moves an archived thread from the archive back to the inbox */
 "UNARCHIVE_ACTION" = "Unarchive";