net.jqwik.engine.support.JqwikKotlinSupport Maven / Gradle / Ivy
package net.jqwik.engine.support;
import java.lang.annotation.*;
import java.lang.reflect.*;
public class JqwikKotlinSupport {
public static String javaOrKotlinName(Method targetMethod) {
String name = targetMethod.getName();
if (isKotlinClass(targetMethod.getDeclaringClass())) {
if (isKotlinInternal(targetMethod)) {
name = nameWithoutInternalPart(name);
}
if (hasMangledName(targetMethod)) {
name = nameWithoutInlinedParameterHashes(name);
}
}
return name;
}
private static boolean isKotlinInternal(Method method) {
if ((method.getModifiers() & Modifier.PUBLIC) == 0) {
return false;
}
// Kotlin appends "$" to internal method names in Java bytecode
// However, it's not necessarily the module name available from Class.getModule().getName() in java
int lastDollarIndex = method.getName().lastIndexOf('$');
return lastDollarIndex > 0 && lastDollarIndex < (method.getName().length() - 1);
}
private static boolean hasMangledName(Method method) {
String name = isKotlinInternal(method) ? nameWithoutInternalPart(method.getName()): method.getName();
return hasInlinedParameters(name);
}
private static boolean hasInlinedParameters(String name) {
// Kotlin appends a 7-char-hash separated by a hyphen to method names
// whenever the underlying Kotlin method uses inlined parameter type, e.g. UInt
// See https://ncorti.com/blog/name-mangling-in-kotlin
int lastIndexOfHyphen = name.lastIndexOf('-');
return lastIndexOfHyphen >= 0 && lastIndexOfHyphen == (name.length() - 8);
}
// Learned mechanism to detect Kotlin class in https://stackoverflow.com/a/39806722
private static boolean isKotlinClass(Class aClass) {
for (Annotation annotation : aClass.getDeclaredAnnotations()) {
if (annotation.annotationType().getTypeName().equals("kotlin.Metadata")) {
return true;
}
}
return false;
}
private static String nameWithoutInternalPart(String name) {
int lastDollarPosition = name.lastIndexOf('$');
return name.substring(0, lastDollarPosition);
}
private static String nameWithoutInlinedParameterHashes(String name) {
int lastDollarPosition = name.lastIndexOf('-');
return name.substring(0, lastDollarPosition);
}
}