Respond to CR.

Signal/src/ViewControllers/Registration/OnboardingPhoneNumberViewController.swift

@@ -371,7 +371,7 @@ public class OnboardingPhoneNumberViewController: OnboardingBaseViewController {
 
 extension OnboardingPhoneNumberViewController: UITextFieldDelegate {
     public func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
-        ViewControllerUtils.phoneNumber(textField, shouldChangeCharactersIn: range, replacementString: string, countryCode: countryCode, prefix: callingCode)
+        ViewControllerUtils.phoneNumber(textField, shouldChangeCharactersIn: range, replacementString: string, callingCode: callingCode)
 
         isPhoneNumberInvalid = false
         updateValidationWarnings()

Signal/src/ViewControllers/Registration/RegistrationViewController.m

@@ -552,7 +552,7 @@ NSString *const kKeychainKey_LastRegisteredPhoneNumber = @"kKeychainKey_LastRegi
     [ViewControllerUtils phoneNumberTextField:textField
                 shouldChangeCharactersInRange:range
                             replacementString:insertionText
-                                  countryCode:_callingCode];
+                                  callingCode:_callingCode];
 
     return NO; // inform our caller that we took care of performing the change
 }

SignalMessaging/ViewControllers/SelectRecipientViewController.m

@@ -423,7 +423,7 @@ NSString *const kSelectRecipientViewControllerCellIdentifier = @"kSelectRecipien
     [ViewControllerUtils phoneNumberTextField:textField
                 shouldChangeCharactersInRange:range
                             replacementString:insertionText
-                                  countryCode:_callingCode];
+                                  callingCode:_callingCode];
 
     [self updatePhoneNumberButtonEnabling];
 

SignalMessaging/ViewControllers/ViewControllerUtils.h

@@ -17,18 +17,12 @@ extern NSString *const TappedStatusBarNotification;
 // This convenience function can be used to reformat the contents of
 // a phone number text field as the user modifies its text by typing,
 // pasting, etc.
+//
+// "callingCode" should be of the form: "+1".
 + (void)phoneNumberTextField:(UITextField *)textField
     shouldChangeCharactersInRange:(NSRange)range
                 replacementString:(NSString *)insertionText
-                      countryCode:(NSString *)countryCode;
-
-// If non-null, the prefix should represent the calling code
-// prefix for the number, e.g. +1.
-+ (void)phoneNumberTextField:(UITextField *)textField
-    shouldChangeCharactersInRange:(NSRange)range
-                replacementString:(NSString *)insertionText
-                      countryCode:(NSString *)countryCode
-                           prefix:(nullable NSString *)prefix;
+                      callingCode:(NSString *)callingCode;
 
 + (void)ows2FAPINTextField:(UITextField *)textField
     shouldChangeCharactersInRange:(NSRange)range

SignalMessaging/ViewControllers/ViewControllerUtils.m

@@ -21,20 +21,7 @@ const NSUInteger kMax2FAPinLength = 16;
 + (void)phoneNumberTextField:(UITextField *)textField
     shouldChangeCharactersInRange:(NSRange)range
                 replacementString:(NSString *)insertionText
-                      countryCode:(NSString *)countryCode
-{
-    return [self phoneNumberTextField:textField
-        shouldChangeCharactersInRange:range
-                    replacementString:insertionText
-                          countryCode:countryCode
-                               prefix:nil];
-}
-
-+ (void)phoneNumberTextField:(UITextField *)textField
-    shouldChangeCharactersInRange:(NSRange)range
-                replacementString:(NSString *)insertionText
-                      countryCode:(NSString *)countryCode
-                           prefix:(nullable NSString *)prefix
+                      callingCode:(NSString *)callingCode
 {
     // Phone numbers takes many forms.
     //
@@ -92,79 +79,18 @@ const NSUInteger kMax2FAPinLength = 16;
 
     NSString *textToFormat = textAfterChange;
     NSString *formattedText = [PhoneNumber bestEffortFormatPartialUserSpecifiedTextToLookLikeAPhoneNumber:textToFormat
-                                                                           withSpecifiedCountryCodeString:countryCode];
+                                                                           withSpecifiedCountryCodeString:callingCode];
     NSUInteger cursorPositionAfterReformat = [PhoneNumberUtil translateCursorPosition:cursorPositionAfterChange
                                                                                  from:textToFormat
                                                                                    to:formattedText
                                                                     stickingRightward:isJustDeletion];
 
-    // PhoneNumber's formatting logic requires a calling code.
-    //
-    // If we want to edit the phone number separately from the calling code
-    // (e.g. in the new onboarding views), we need to temporarily prepend the
-    // calling code during formatting, then remove it afterward.  This is
-    // non-trivial since the calling code itself can be affected by the
-    // formatting.  Additionally, we need to ensure that this prepend/remove
-    // doesn't affect the cursor position.
-    BOOL hasPrefix = prefix.length > 0;
-    if (hasPrefix) {
-        // Prepend the prefix.
-        NSString *textToFormatWithPrefix = [prefix stringByAppendingString:textAfterChange];
-        // Format with the prefix.
-        NSString *formattedTextWithPrefix =
-            [PhoneNumber bestEffortFormatPartialUserSpecifiedTextToLookLikeAPhoneNumber:textToFormatWithPrefix
-                                                         withSpecifiedCountryCodeString:countryCode];
-        // Determine the new cursor position with the prefix.
-        NSUInteger cursorPositionWithPrefix = [PhoneNumberUtil translateCursorPosition:cursorPositionAfterChange
-                                                                                  from:textToFormat
-                                                                                    to:formattedTextWithPrefix
-                                                                     stickingRightward:isJustDeletion];
-        // Try to determine how much of the formatted text is derived
-        // from the prefix.
-        NSString *_Nullable formattedPrefix =
-            [self findFormattedPrefixForPrefix:prefix formattedText:formattedTextWithPrefix];
-        if (formattedPrefix && cursorPositionWithPrefix >= formattedPrefix.length) {
-            // Remove the prefix from the formatted text.
-            formattedText = [formattedTextWithPrefix substringFromIndex:formattedPrefix.length];
-            // Adjust the cursor position accordingly.
-            cursorPositionAfterReformat = cursorPositionWithPrefix - formattedPrefix.length;
-        }
-    }
-
     textField.text = formattedText;
     UITextPosition *pos =
         [textField positionFromPosition:textField.beginningOfDocument offset:(NSInteger)cursorPositionAfterReformat];
     [textField setSelectedTextRange:[textField textRangeFromPosition:pos toPosition:pos]];
 }
 
-+ (nullable NSString *)findFormattedPrefixForPrefix:(NSString *)prefix formattedText:(NSString *)formattedText
-{
-    NSCharacterSet *characterSet = [[NSCharacterSet characterSetWithCharactersInString:@"+0123456789"] invertedSet];
-    NSString *filteredPrefix =
-        [[prefix componentsSeparatedByCharactersInSet:characterSet] componentsJoinedByString:@""];
-    NSString *filteredText =
-        [[formattedText componentsSeparatedByCharactersInSet:characterSet] componentsJoinedByString:@""];
-    if (filteredPrefix.length < 1 || filteredText.length < 1 || ![filteredText hasPrefix:filteredPrefix]) {
-        OWSFailDebug(@"Invalid prefix: '%@' for formatted text: '%@'", prefix, formattedText);
-        return nil;
-    }
-    NSString *filteredTextWithoutPrefix = [filteredText substringFromIndex:filteredPrefix.length];
-    // To find the "formatted prefix", try to find the shortest "tail" of formattedText
-    // which after being filtered is equivalent to the "filtered text" - "filter prefix".
-    // The "formatted prefix" is the "head" that corresponds to that "tail".
-    for (NSUInteger substringLength = 1; substringLength < formattedText.length - 1; substringLength++) {
-        NSUInteger pivot = formattedText.length - substringLength;
-        NSString *head = [formattedText substringToIndex:pivot];
-        NSString *tail = [formattedText substringFromIndex:pivot];
-        NSString *filteredTail =
-            [[tail componentsSeparatedByCharactersInSet:characterSet] componentsJoinedByString:@""];
-        if ([filteredTail isEqualToString:filteredTextWithoutPrefix]) {
-            return head;
-        }
-    }
-    return nil;
-}
-
 + (void)ows2FAPINTextField:(UITextField *)textField
     shouldChangeCharactersInRange:(NSRange)range
                 replacementString:(NSString *)insertionText