/*
* Copyright 2014 - 2018 Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.bytebuddy.implementation.bytecode.assign;
import edu.umd.cs.findbugs.annotations.
SuppressFBWarnings;
import net.bytebuddy.description.type.
TypeDescription;
import net.bytebuddy.implementation.bytecode.
StackManipulation;
import net.bytebuddy.implementation.bytecode.assign.primitive.
PrimitiveTypeAwareAssigner;
import net.bytebuddy.implementation.bytecode.assign.primitive.
VoidAwareAssigner;
import net.bytebuddy.implementation.bytecode.assign.reference.
ReferenceTypeAwareAssigner;
/**
* An assigner is responsible for converting some type {@code A} to another type {@code B} if possible.
* <p> </p>
* An assigner is for example responsible for type casting, auto boxing or unboxing or for the widening of primitive
* types.
*/
@
SuppressFBWarnings(value = "IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION", justification = "Safe initialization is implied")
public interface
Assigner {
/**
* A default assigner that can handle {@code void}, primitive types and references.
*/
Assigner DEFAULT = new
VoidAwareAssigner(new
PrimitiveTypeAwareAssigner(
ReferenceTypeAwareAssigner.
INSTANCE));
/**
* @param source The original type that is to be transformed into the {@code targetType}.
* @param target The target type into which the {@code sourceType} is to be converted.
* @param typing A hint whether the assignment should consider the runtime type of the source type,
* i.e. if type down or cross castings are allowed. If this hint is set, this is
* also an indication that {@code void} to non-{@code void} assignments are permitted.
* @return A stack manipulation that transforms the {@code sourceType} into the {@code targetType} if this
* is possible. An illegal stack manipulation otherwise.
*/
StackManipulation assign(
TypeDescription.
Generic source,
TypeDescription.
Generic target,
Typing typing);
/**
* Indicates for a type assignment, if a type casting should be applied in case that two types are not statically assignable.
* Also, a dynamic typing indicates that void values are assignable to other types by assigning the target type's default value.
*/
enum
Typing {
/**
* Requires static typing.
*/
STATIC(false),
/**
* Allows dynamic typing.
*/
DYNAMIC(true);
/**
* {@code true} if dynamic typing is a legitimate choice.
*/
private final boolean
dynamic;
/**
* Creates a new typing hint.
*
* @param dynamic {@code true} if dynamic typing is a legitimate choice.
*/
Typing(boolean
dynamic) {
this.
dynamic =
dynamic;
}
/**
* Resolves a typing constant for the presented boolean where {@code true} indicates that dynamic typing is a legitimate choice.
*
* @param dynamic An indicator for if dynamic typing is a legitimate choice.
* @return A corresponding typing constant.
*/
public static
Typing of(boolean
dynamic) {
return
dynamic
?
DYNAMIC
:
STATIC;
}
/**
* Checks if this instance's typing behavior permits dynamic typing.
*
* @return {@code true} if dynamic typing is a legitimate choice.
*/
public boolean
isDynamic() {
return
dynamic;
}
}
/**
* An assigner that only allows to assign types if they are equal to another.
*/
enum
EqualTypesOnly implements
Assigner {
/**
* An type assigner that only considers equal generic types to be assignable.
*/
GENERIC {
/** {@inheritDoc} */
public
StackManipulation assign(
TypeDescription.
Generic source,
TypeDescription.
Generic target,
Typing typing) {
return
source.
equals(
target)
?
StackManipulation.
Trivial.
INSTANCE
:
StackManipulation.
Illegal.
INSTANCE;
}
},
/**
* A type assigner that considers two generic types to be equal if their erasure is equal.
*/
ERASURE {
/** {@inheritDoc} */
public
StackManipulation assign(
TypeDescription.
Generic source,
TypeDescription.
Generic target,
Typing typing) {
return
source.
asErasure().
equals(
target.
asErasure())
?
StackManipulation.
Trivial.
INSTANCE
:
StackManipulation.
Illegal.
INSTANCE;
}
};
}
/**
* An assigner that does not allow any assignments.
*/
enum
Refusing implements
Assigner {
/**
* The singleton instance.
*/
INSTANCE;
/**
* {@inheritDoc}
*/
public
StackManipulation assign(
TypeDescription.
Generic source,
TypeDescription.
Generic target,
Typing typing) {
return
StackManipulation.
Illegal.
INSTANCE;
}
}
}