/**

* @name Use of regexp to match a set of constant string

* @description Comparing against constant strings instead of a regexp can improve performance

* @kind problem

* @problem.severity recommendation

* @id ql/use-string-compare

* @tags maintainability

* @precision high

*/

import ql

import codeql_ql.ast.internal.Type

predicate problem(MemberCall call) {

call.getBase().getType().getASuperType*().(PrimitiveType).getName() = "string" and

(

call.getMemberName() = "regexpMatch" and

call.getNumberOfArguments() = 1 and

call.getArgument(0).(String).getValue().regexpMatch("([a-zA-Z0-9]+\\|)*[a-zA-Z0-9]+")

or

exists(string reg | call.getMemberName() = "matches" |

call.getNumberOfArguments() = 1 and

reg = call.getArgument(0).(String).getValue() and

not reg.regexpMatch(".*(%|_).*")

)

)

}

from AstNode node

where problem(node)

select node, "Use string comparison instead of regexp to compare against a constant set of string."