Fix rebooted and not unlocked case for extension

Riot/Utils/DataProtectionHelper.swift

@@ -0,0 +1,62 @@
+/*
+Copyright 2020 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import Foundation
+
+final class DataProtectionHelper {
+    
+    static func isDeviceInRebootedAndLockedState(appGroupIdentifier: String? = nil) -> Bool {
+        do {
+            let str = String.unique
+            let dummyData = str.data(using: .utf8)!
+
+            var url: URL!
+            if let identifier = appGroupIdentifier {
+                let containerURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: identifier)
+                if containerURL == nil {
+                    url = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
+                } else {
+                    url = containerURL?.appendingPathComponent("Library/Caches")
+                }
+            } else {
+                url = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
+            }
+
+            url = url.appendingPathComponent(String.unique)
+
+            try dummyData.write(to: url, options: .completeFileProtectionUntilFirstUserAuthentication)
+            let readData = try Data(contentsOf: url)
+            let readString = String(data: readData, encoding: .utf8)
+            try FileManager.default.removeItem(at: url)
+            if readString != str {
+                return true
+            }
+        } catch {
+            return true
+        }
+        return false
+    }
+    
+}
+
+extension String {
+    
+    /// Returns a globally unique string
+    static var unique: String {
+        return ProcessInfo.processInfo.globallyUniqueString
+    }
+    
+}