match highlight behavior with search behavior

Signal/src/ConversationSearch.swift

@@ -82,11 +82,12 @@ extension ConversationSearchController: UISearchResultsUpdating {
     public func updateSearchResults(for searchController: UISearchController) {
         Logger.verbose("searchBar.text: \( searchController.searchBar.text ?? "<blank>")")
 
-        guard let searchText = searchController.searchBar.text?.stripped else {
+        guard let rawSearchText = searchController.searchBar.text?.stripped else {
             self.resultsBar.updateResults(resultSet: nil)
             self.delegate?.conversationSearchController(self, didUpdateSearchResults: nil)
             return
         }
+        let searchText = FullTextSearchFinder.normalize(text: rawSearchText)
         BenchManager.startEvent(title: "Conversation Search", eventId: searchText)
 
         guard searchText.count >= ConversationSearchController.kMinimumSearchTextLength else {

Signal/src/ViewControllers/ConversationView/Cells/OWSMessageBubbleView.m

@@ -708,10 +708,12 @@ NS_ASSUME_NONNULL_BEGIN
         initWithString:text
             attributes:@{ NSFontAttributeName : font, NSForegroundColorAttributeName : textColor }];
     if (searchText.length >= ConversationSearchController.kMinimumSearchTextLength) {
+        NSString *searchableText = [FullTextSearchFinder normalizeWithText:searchText];
         NSError *error;
-        NSRegularExpression *regex = [[NSRegularExpression alloc] initWithPattern:searchText
-                                                                          options:NSRegularExpressionCaseInsensitive
-                                                                            error:&error];
+        NSRegularExpression *regex =
+            [[NSRegularExpression alloc] initWithPattern:[NSRegularExpression escapedPatternForString:searchableText]
+                                                 options:NSRegularExpressionCaseInsensitive
+                                                   error:&error];
         OWSAssertDebug(error == nil);
         for (NSTextCheckingResult *match in
             [regex matchesInString:text options:NSMatchingWithoutAnchoringBounds range:NSMakeRange(0, text.length)]) {

SignalServiceKit/src/Storage/FullTextSearchFinder.swift

@@ -138,6 +138,7 @@ public class FullTextSearchFinder: NSObject {
     // This is a hot method, especially while running large migrations.
     // Changes to it should go through a profiler to make sure large migrations
     // aren't adversely affected.
+    @objc
     public class func normalize(text: String) -> String {
         // 1. Filter out invalid characters.
         let filtered = text.removeCharacters(characterSet: charactersToRemove)