class.methods.HashCode.scala Maven / Gradle / Ivy
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package com.julianpeeters.caseclass.generator
import org.objectweb.asm._
import Opcodes._
import scala.reflect.runtime.universe._
//HashCode has two methods: the main "dump" method, and the helper "matchFields" that it calls
case class HashCode(cw: ClassWriter, var mv: MethodVisitor, caseClassName: String, fieldData: List[EnrichedField]) {
val userDefinedTypes = ClassStore.generatedClasses.keys.toList
def dump = {
mv = cw.visitMethod(ACC_PUBLIC, "hashCode", "()I", null, null);
mv.visitCode();
fieldData.length match {
case 0 => {
mv.visitFieldInsn(GETSTATIC, "scala/runtime/ScalaRunTime$", "MODULE$", "Lscala/runtime/ScalaRunTime$;");
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, "scala/runtime/ScalaRunTime$", "_hashCode", "(Lscala/Product;)I");
}
case x if x > 0 => { //type erase the generics, then check if all the types are from the following list
if (fieldData.map(fd => fd.fieldType.erasure).forall(t => (List(typeOf[Nothing].erasure, typeOf[Null].erasure, typeOf[Any].erasure, typeOf[AnyRef].erasure, typeOf[Object].erasure, typeOf[String].erasure, typeOf[Option[Any]].erasure, typeOf[List[Any]].erasure) ::: userDefinedTypes).contains(t))) { //if all the valueMembers are in this list (of "empty" types, look different when paired with "real")
mv.visitFieldInsn(GETSTATIC, "scala/runtime/ScalaRunTime$", "MODULE$", "Lscala/runtime/ScalaRunTime$;");
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, "scala/runtime/ScalaRunTime$", "_hashCode", "(Lscala/Product;)I");
}
else {
mv.visitLdcInsn(new Integer(-889275714));
mv.visitVarInsn(ISTORE, 1);
mv.visitVarInsn(ILOAD, 1);
val fields = if (fieldData.map(n => n.fieldType).contains(typeOf[Nothing])) fieldData.reverse.dropWhile(valueMember => valueMember.fieldType != typeOf[Nothing]).reverse; else fieldData
// if there is more than one non-"empty" type(see the list above), drop all types after the first Nothing.
fields.foreach(valueMember => matchFields(valueMember))
fieldData.length match {
case 1 => mv.visitInsn(ICONST_1);
case 2 => mv.visitInsn(ICONST_2);
case 3 => mv.visitInsn(ICONST_3);
case 4 => mv.visitInsn(ICONST_4);
case 5 => mv.visitInsn(ICONST_5);
case x if x > 5 => mv.visitIntInsn(BIPUSH, x);
}
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "finalizeHash", "(II)I");
}
if (!fieldData.map(n => n.fieldType).contains(typeOf[Nothing])) mv.visitInsn(IRETURN);
mv.visitMaxs(2, 2);
mv.visitEnd();
}
}
}
def matchFields(valueMember: EnrichedField) = {
valueMember.fieldType match {
case l if (l =:= typeOf[Byte] |
l =:= typeOf[Char] |
l =:= typeOf[Short] |
l =:= typeOf[Int] |
l =:= typeOf[Long] |
l =:= typeOf[Float] |
l =:= typeOf[Double] |
l =:=typeOf[Unit] |
l =:=typeOf[Null] ) => {
valueMember.fieldType match {
case l if (l =:= typeOf[Byte] | l =:= typeOf[Short] | l =:= typeOf[Int] | l =:= typeOf[Char]) => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
}
case l if (l =:= typeOf[Long] | l =:= typeOf[Float] | l =:= typeOf[Double]) => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", valueMember.fieldType + "Hash", "(" + valueMember.typeData.typeDescriptor + ")I");
}
case l if (l =:= typeOf[Unit] | l =:= typeOf[Null]) => {
mv.visitInsn(ICONST_0);
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "mix", "(II)I");
mv.visitVarInsn(ISTORE, 1);
mv.visitVarInsn(ILOAD, 1);
}
case _ => error("could not generate hashcode method: unsupported type")
}
}
case b if b =:= typeOf[Boolean] => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
val l0 = new Label();
mv.visitJumpInsn(IFEQ, l0);
mv.visitIntInsn(SIPUSH, 1231);
val l1 = new Label();
mv.visitJumpInsn(GOTO, l1);
mv.visitLabel(l0);
mv.visitFrame(Opcodes.F_FULL, 2, Array[Object] (caseClassName, Opcodes.INTEGER), 1, Array[Object] (Opcodes.INTEGER));
mv.visitIntInsn(SIPUSH, 1237);
mv.visitLabel(l1);
mv.visitFrame(Opcodes.F_FULL, 2, Array[Object] (caseClassName, Opcodes.INTEGER), 2, Array[Object] (Opcodes.INTEGER, Opcodes.INTEGER));
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "mix", "(II)I");
mv.visitVarInsn(ISTORE, 1);
mv.visitVarInsn(ILOAD, 1);
}
//if there were only one valueMember, the "if" statement would have taken care of things
//so this has to have come after
case la @ TypeRef(pre, symbol, args) if ((la <:< typeOf[List[Any]] | la <:< typeOf[Option[Any]] | la <:< typeOf[Stream[Any]]) && args.length == 1 ) => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "anyHash", "(Ljava/lang/Object;)I");
}
case s if (s =:= typeOf[String] | s =:= typeOf[Object] | s =:= typeOf[Any] | s =:= typeOf[AnyRef]) => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "anyHash", "(Ljava/lang/Object;)I");
}
case n if n =:= typeOf[Nothing] => { //if typeOf[Nothing] is a value member's type, it will be the last one in the list of value members
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()Lscala/runtime/Nothing$;");
mv.visitInsn(ATHROW);
}
// user defined or other case classes
case name @ TypeRef(pre, symbol, args) if userDefinedTypes.contains(name) => {
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKEVIRTUAL, caseClassName, valueMember.fieldName, "()" + valueMember.typeData.typeDescriptor);
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "anyHash", "(Ljava/lang/Object;)I");
}
case _ => error("cannot generate HashCode method: unsupported type")
}
//Booleans and Units get special treatment because their ASM lines have a "mix" already
if (valueMember.fieldType != typeOf[Boolean] && valueMember.fieldType != typeOf[Unit] && valueMember.fieldType != typeOf[Null]) {
mv.visitMethodInsn(INVOKESTATIC, "scala/runtime/Statics", "mix", "(II)I");
mv.visitVarInsn(ISTORE, 1);
mv.visitVarInsn(ILOAD, 1);
}
}
}
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