/*
* Copyright 2008 Google Inc.
*
* 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 com.google.gwt.dev.shell.rewrite;
import com.google.gwt.dev.asm.ClassVisitor;
import com.google.gwt.dev.asm.MethodVisitor;
import com.google.gwt.dev.asm.Opcodes;
import com.google.gwt.dev.asm.commons.Remapper;
import com.google.gwt.dev.shell.rewrite.HostedModeClassRewriter.InstanceMethodOracle;
import java.util.Set;
/**
* Rewrites references to modified JSO subtypes.
*
* <ol>
* <li>Changes the owner type for instructions that reference items in a JSO
* class to the implementation class.</li>
* <li>Rewrites instance calls to JSO classes into static calls.</li>
* <li>Updates the descriptor for such call sites to includes a synthetic
* <code>this</code> parameter. This modified method has same stack behavior
* as the original instance method.</li>
* </ol>
*/
class RewriteRefsToJsoClasses extends ClassVisitor {
/**
* A method body rewriter to actually rewrite call sites.
*/
private class MyMethodAdapter extends MethodVisitor {
private Remapper remapper = new Remapper() {
@Override
public String map(String typeName) {
if (jsoDescriptors.contains(typeName)) {
return HostedModeClassRewriter.JAVASCRIPTOBJECT_IMPL_DESC;
}
return typeName;
}
};
public MyMethodAdapter(MethodVisitor mv) {
super(Opcodes.ASM4, mv);
}
@Override
public void visitFieldInsn(int opcode, String owner, String name,
String desc) {
if (jsoDescriptors.contains(owner)) {
// Change the owner to the rewritten class.
owner += "$";
}
super.visitFieldInsn(opcode, owner, name, desc);
}
@Override
public void visitLdcInsn(Object cst) {
cst = remapper.mapValue(cst);
super.visitLdcInsn(cst);
}
@Override
public void visitMethodInsn(int opcode, String owner, String name,
String desc) {
if (jsoDescriptors.contains(owner)) {
// Find the class that actually declared the method.
if (opcode == Opcodes.INVOKEVIRTUAL) {
owner = mapper.findOriginalDeclaringClass(owner, name + desc);
}
if (!owner.equals("java/lang/Object")) {
if (opcode == Opcodes.INVOKEVIRTUAL
|| opcode == Opcodes.INVOKESPECIAL) {
// Instance/super call to JSO; rewrite as static.
opcode = Opcodes.INVOKESTATIC;
desc = HostedModeClassRewriter.addSyntheticThisParam(owner, desc);
name += "$";
}
// Change the owner to implementation class.
owner += "$";
}
}
super.visitMethodInsn(opcode, owner, name, desc);
}
@Override
public void visitMultiANewArrayInsn(String desc, int dims) {
desc = remapper.mapType(desc);
super.visitMultiANewArrayInsn(desc, dims);
}
@Override
public void visitTypeInsn(int opcode, String type) {
if (opcode == Opcodes.ANEWARRAY) {
type = remapper.mapType(type);
}
super.visitTypeInsn(opcode, type);
}
}
/**
* An unmodifiable set of descriptors containing <code>JavaScriptObject</code>
* and all subclasses.
*/
protected final Set<String> jsoDescriptors;
/**
* Maps methods to the class in which they are declared.
*/
private InstanceMethodOracle mapper;
/**
* Construct a new rewriter instance.
*
* @param cv the visitor to chain to
* @param jsoDescriptors an unmodifiable set of descriptors containing
* <code>JavaScriptObject</code> and all subclasses
* @param mapper maps methods to the class in which they are declared
*/
public RewriteRefsToJsoClasses(ClassVisitor cv, Set<String> jsoDescriptors,
InstanceMethodOracle mapper) {
super(Opcodes.ASM4, cv);
this.jsoDescriptors = jsoDescriptors;
this.mapper = mapper;
}
@Override
public MethodVisitor visitMethod(int access, String name, String desc,
String signature, String[] exceptions) {
// Wrap the returned method visitor in my own.
MethodVisitor mv = super.visitMethod(access, name, desc, signature,
exceptions);
return new MyMethodAdapter(mv);
}
}