La/disable ctl for catalina

DuckDuckGo/ContentBlocker/ContentBlockerRulesLists.swift

@@ -77,11 +77,13 @@ final class ContentBlockerRulesLists: DefaultContentBlockerRulesListsSource {
         // Add new ones
         let etag = MD5(data: Self.fbTrackerDataFile)
         let dataSet: TrackerDataManager.DataSet = TrackerDataManager.DataSet(Self.fbTrackerDataSet, etag)
-        let additionalRulesList = ContentBlockerRulesList(name: Constants.clickToLoadRulesListName,
-                                                          trackerData: nil,
-                                                          fallbackTrackerData: dataSet)
+        if #available(OSX 11, *) {  // disable CTL for Catalina and earlier
+            let CTLRulesList = ContentBlockerRulesList(name: Constants.clickToLoadRulesListName,
+                                                              trackerData: nil,
+                                                              fallbackTrackerData: dataSet)
+            result.append(CTLRulesList)
+        }
 
-        result.append(additionalRulesList)
         return result
     }
 }

DuckDuckGo/ContentBlocker/ScriptSourceProviding.swift

@@ -155,12 +155,15 @@ struct ScriptSourceProvider: ScriptSourceProviding {
     private func buildClickToLoadSource() -> String {
         // For now bundle FB SDK and associated config, as they diverged from the extension
         let fbSDK = loadTextFile("fb-sdk", "js")
-        let config = loadTextFile("clickToLoadConfig", "json")
+        var config = loadTextFile("clickToLoadConfig", "json")!
+        if #unavailable(OSX 11) {  // disable CTL for Catalina and earlier
+            config = "{}"
+        }
         let proximaRegFont = loadFont("ProximaNova-Reg-webfont", "woff2")
         let proximaBoldFont = loadFont("ProximaNova-Bold-webfont", "woff2")
         return ContentBlockerRulesUserScript.loadJS("clickToLoad", from: .main, withReplacements: [
             "${fb-sdk.js}": fbSDK!,
-            "${clickToLoadConfig.json}": config!,
+            "${clickToLoadConfig.json}": config,
             "${proximaRegFont}": proximaRegFont!,
             "${proximaBoldFont}": proximaBoldFont!
         ])

DuckDuckGo/Tab/TabExtensions/FBProtectionTabExtension.swift

@@ -58,6 +58,9 @@ extension FBProtectionTabExtension {
 
     @discardableResult
     private func setFBProtection(enabled: Bool) -> Bool {
+        if #unavailable(OSX 11) {  // disable CTL for Catalina and earlier
+            return false
+        }
         guard self.fbBlockingEnabled != enabled else { return false }
         guard let userContentController else {
             assertionFailure("Missing UserContentController")