Swift: Add a 'RemoteFlowSource' class.

Author: MathiasVP

swift/ql/lib/codeql/swift/dataflow/FlowSources.qll

@@ -0,0 +1,18 @@
+/**
+ * Provides classes representing various flow sources for taint tracking.
+ */
+
+private import ExternalFlow
+private import internal.DataFlowPublic
+
+/** A data flow source of remote user input. */
+abstract class RemoteFlowSource extends Node {
+  /** Gets a string that describes the type of this remote flow source. */
+  abstract string getSourceType();
+}
+
+private class ExternalRemoteFlowSource extends RemoteFlowSource {
+  ExternalRemoteFlowSource() { sourceNode(this, "remote") }
+
+  override string getSourceType() { result = "external" }
+}