/*
* Copyright (C) 2009-2014 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.patcher.scripts;
import java.util.List;
import java.util.Set;
import lombok.NonNull;
import lombok.ToString;
import lombok.patcher.Hook;
import lombok.patcher.MethodLogistics;
import lombok.patcher.StackRequest;
import lombok.patcher.TargetMatcher;
import lombok.patcher.TransplantMapper;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
/**
* Will find every 'return' instruction in the target method and will insert right before it a call to the wrapper.
*/
@ToString
public final class WrapReturnValuesScript extends MethodLevelPatchScript {
private final @NonNull Hook wrapper;
private final Set<StackRequest> requests;
private final boolean hijackReturnValue;
private final boolean transplant, insert;
/**
* @param targetMethod The target method to patch.
* @param wrapper A call to this method will be inserted in front of each return in the target method (must be static).
* @param transplant If true, the method content is loaded directly into the target class. Make sure you don't call
* helper methods if you use this!
* @param requests The kinds of parameters you want your hook method to receive.
*/
WrapReturnValuesScript(List<TargetMatcher> matchers, Hook wrapper, boolean transplant, boolean insert, Set<StackRequest> requests) {
super(matchers);
if (wrapper == null) throw new NullPointerException("wrapper");
this.wrapper = wrapper;
this.hijackReturnValue = !wrapper.getMethodDescriptor().endsWith(")V");
this.requests = requests;
this.transplant = transplant;
this.insert = insert;
assert !(insert && transplant);
}
@Override protected MethodPatcher createPatcher(ClassWriter writer, final String classSpec, TransplantMapper transplantMapper) {
final MethodPatcher patcher = new MethodPatcher(writer, transplantMapper, new MethodPatcherFactory() {
public MethodVisitor createMethodVisitor(String name, String desc, MethodVisitor parent, MethodLogistics logistics) {
return new WrapReturnValues(parent, logistics, classSpec);
}
});
if (transplant) patcher.addTransplant(wrapper);
return patcher;
}
private class WrapReturnValues extends MethodVisitor {
private final MethodLogistics logistics;
private final String ownClassSpec;
public WrapReturnValues(MethodVisitor mv, MethodLogistics logistics, String ownClassSpec) {
super(Opcodes.ASM4, mv);
this.logistics = logistics;
this.ownClassSpec = ownClassSpec;
}
@Override public void visitInsn(int opcode) {
if (opcode != logistics.getReturnOpcode()) {
super.visitInsn(opcode);
return;
}
if (requests.contains(StackRequest.RETURN_VALUE)) {
if (!hijackReturnValue) {
//The supposed return value is on stack, but the wrapper wants it and will not supply a new one, so duplicate it.
logistics.generateDupForReturn(mv);
}
} else {
if (hijackReturnValue) {
//The supposed return value is on stack, but the wrapper doesn't want it and will supply a new one, so, kill it.
logistics.generatePopForReturn(mv);
}
}
if (requests.contains(StackRequest.THIS)) logistics.generateLoadOpcodeForThis(mv);
for (StackRequest param : StackRequest.PARAMS_IN_ORDER) {
if (!requests.contains(param)) continue;
logistics.generateLoadOpcodeForParam(param.getParamPos(), mv);
}
if (insert) insertMethod(wrapper, mv);
else super.visitMethodInsn(Opcodes.INVOKESTATIC, transplant ? ownClassSpec : wrapper.getClassSpec(), wrapper.getMethodName(),
wrapper.getMethodDescriptor(), false);
super.visitInsn(opcode);
}
}
}