/*
* 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.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.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
/**
* Receive (optional) 'this' reference as well as any parameters, then choose to return early with provided value, or let
* the method continue.
*/
public class ExitFromMethodEarlyScript extends MethodLevelPatchScript {
private final Hook decisionWrapper, valueWrapper;
private final Set<StackRequest> requests;
private final boolean transplant, insert;
private final boolean insertCallOnly;
ExitFromMethodEarlyScript(List<TargetMatcher> matchers, Hook decisionWrapper, Hook valueWrapper, boolean transplant, boolean insert, Set<StackRequest> requests) {
super(matchers);
this.decisionWrapper = decisionWrapper;
this.valueWrapper = valueWrapper;
this.requests = requests;
this.transplant = transplant;
this.insert = insert;
this.insertCallOnly = decisionWrapper != null && decisionWrapper.getMethodDescriptor().endsWith(")V");
if (!this.insertCallOnly && decisionWrapper != null && !decisionWrapper.getMethodDescriptor().endsWith(")Z")) {
throw new IllegalArgumentException("The decisionWrapper method must either return 'boolean' or return 'void'.");
}
assert !(insert && transplant);
}
@Override protected MethodPatcher createPatcher(ClassWriter writer, final String classSpec, TransplantMapper transplantMapper) {
MethodPatcher patcher = new MethodPatcher(writer, transplantMapper, new MethodPatcherFactory() {
public MethodVisitor createMethodVisitor(String name, String desc, MethodVisitor parent, MethodLogistics logistics) {
if (valueWrapper == null && !insertCallOnly && logistics.getReturnOpcode() != Opcodes.RETURN) {
throw new IllegalStateException("method " + name + desc + " must return something, but " +
"you did not provide a value hook method.");
}
return new ExitEarly(parent, logistics, classSpec);
}
});
if (transplant) {
patcher.addTransplant(decisionWrapper);
if (valueWrapper != null) patcher.addTransplant(valueWrapper);
}
return patcher;
}
private class ExitEarly extends MethodVisitor {
private final MethodLogistics logistics;
private final String ownClassSpec;
public ExitEarly(MethodVisitor mv, MethodLogistics logistics, String ownClassSpec) {
super(Opcodes.ASM4, mv);
this.logistics = logistics;
this.ownClassSpec = ownClassSpec;
}
@Override public void visitCode() {
if (decisionWrapper == null) {
//Always return early.
if (logistics.getReturnOpcode() == Opcodes.RETURN) {
mv.visitInsn(Opcodes.RETURN);
return;
}
insertValueWrapperCall();
return;
}
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(decisionWrapper, mv);
else super.visitMethodInsn(Opcodes.INVOKESTATIC, transplant ? ownClassSpec : decisionWrapper.getClassSpec(),
decisionWrapper.getMethodName(), decisionWrapper.getMethodDescriptor(), false);
if (insertCallOnly) {
super.visitCode();
return;
}
/* Inject:
* if ([result of decision hook]) {
* //if method body is not VOID:
* reload-on-stack-what-needs-reloading
* invokeReturnValueHook
* //end if
* xRETURN;
* }
*/
Label label0 = new Label();
mv.visitJumpInsn(Opcodes.IFEQ, label0);
if (logistics.getReturnOpcode() == Opcodes.RETURN) {
mv.visitInsn(Opcodes.RETURN);
} else {
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(valueWrapper, mv);
else super.visitMethodInsn(Opcodes.INVOKESTATIC, transplant ? ownClassSpec : valueWrapper.getClassSpec(),
valueWrapper.getMethodName(), valueWrapper.getMethodDescriptor(), false);
logistics.generateReturnOpcode(mv);
}
mv.visitLabel(label0);
mv.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
super.visitCode();
}
private void insertValueWrapperCall() {
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(valueWrapper, mv);
else super.visitMethodInsn(Opcodes.INVOKESTATIC, transplant ? ownClassSpec : valueWrapper.getClassSpec(),
valueWrapper.getMethodName(), valueWrapper.getMethodDescriptor(), false);
logistics.generateReturnOpcode(mv);
}
}
}