refactor: move escapeIdent function to Identifiers.hs

Moves the functions `escapeIdent` and `trimNullChars` to
SchemaCache/Identifiers.hs module.

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

src/PostgREST/SchemaCache/Identifiers.hs

@@ -8,8 +8,10 @@ module PostgREST.SchemaCache.Identifiers
   , Schema
   , TableName
   , dumpQi
+  , escapeIdent
   , isAnyElement
   , toQi
+  , trimNullChars
   ) where
 
 import qualified Data.Aeson as JSON
@@ -46,6 +48,12 @@ toQi txt = case T.drop 1 <$> T.breakOn "." txt of
   (i, "") -> QualifiedIdentifier mempty i
   (s, i)  -> QualifiedIdentifier s i
 
+escapeIdent :: Text -> Text
+escapeIdent x = "\"" <> T.replace "\"" "\"\"" (trimNullChars x) <> "\""
+
+trimNullChars :: Text -> Text
+trimNullChars = T.takeWhile (/= '\x0')
+
 type Schema = Text
 type TableName = Text
 type FieldName = Text