Merge pull request #417 from Dominaezzz/kt-opt

Some optimisations

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/keysbackup/KeysBackupPassword.kt

@@ -142,12 +142,11 @@ private fun deriveKey(password: String,
  * Generate a 32 chars salt
  */
 private fun generateSalt(): String {
-    var salt = ""
-
-    do {
-        salt += UUID.randomUUID().toString()
-    } while (salt.length < SALT_LENGTH)
-
+    val salt = buildString {
+        do {
+            append(UUID.randomUUID().toString())
+        } while (length < SALT_LENGTH)
+    }
 
     return salt.substring(0, SALT_LENGTH)
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/model/MXKey.kt

@@ -63,9 +63,7 @@ data class MXKey(
     fun signatureForUserId(userId: String, signkey: String): String? {
         // sanity checks
         if (userId.isNotBlank() && signkey.isNotBlank()) {
-            if (signatures.containsKey(userId)) {
-                return signatures[userId]?.get(signkey)
-            }
+            return signatures[userId]?.get(signkey)
         }
 
         return null