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package lombok.agent.eclipse;
import org.objectweb.asm.ClassAdapter;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodAdapter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
class EclipseParserTransformer {
private static final String COMPILATION_UNIT_DECLARATION_SIG =
"Lorg/eclipse/jdt/internal/compiler/ast/CompilationUnitDeclaration;";
private static final String TOPATCH_METHOD_NAME = "endParse";
private static final String TOPATCH_METHOD_DESC = "(I)" + COMPILATION_UNIT_DECLARATION_SIG;
private final byte[] in;
EclipseParserTransformer(byte[] classfileBuffer) {
in = classfileBuffer;
}
byte[] transform() {
ClassReader reader = new ClassReader(in);
ClassWriter writer = new ClassWriter(reader, 0);
ClassAdapter adapter = new ParserPatcherAdapter(writer);
reader.accept(adapter, 0);
return writer.toByteArray();
}
private static class ParserPatcherAdapter extends ClassAdapter {
public ParserPatcherAdapter(ClassVisitor cv) {
super(cv);
}
@Override public MethodVisitor visitMethod(int access, String name, String desc,
String signature, String[] exceptions) {
MethodVisitor writerVisitor = super.visitMethod(access, name, desc, signature, exceptions);
if ( !TOPATCH_METHOD_NAME.equals(name) || !TOPATCH_METHOD_DESC.equals(desc) ) return writerVisitor;
return new PatcherMethodVisitor(writerVisitor);
}
}
static class PatcherMethodVisitor extends MethodAdapter {
private static final String TARGET_STATIC_CLASS = "java/lombok/ClassLoaderWorkaround";
private static final String TARGET_STATIC_METHOD_NAME = "transformCompilationUnitDeclaration";
private static final String TARGET_STATIC_METHOD_DESC = "(Ljava/lang/Object;)V";
private boolean alreadyCalled = false;
PatcherMethodVisitor(MethodVisitor mv) {
super(mv);
}
@Override public void visitInsn(int opcode) {
if ( opcode == Opcodes.ARETURN ) insertHookCall();
super.visitInsn(opcode);
}
@Override public void visitMethodInsn(int opcode, String owner, String name,
String desc) {
if ( opcode == Opcodes.INVOKESTATIC &&
TARGET_STATIC_CLASS.equals(owner) && TARGET_STATIC_METHOD_NAME.equals(name) ) alreadyCalled = true;
super.visitMethodInsn(opcode, owner, name, desc);
}
/** When this method is called, the stack should hold the reference to the
* just-parsed CompilationUnitDeclaration object that is about to be returned
* to whomever wants it. We will put a call to a method of our choosing in,
* which will transform the CUD. The stack is not modified (that is, that method
* returns a CUD).
*/
private void insertHookCall() {
if ( alreadyCalled ) return;
super.visitInsn(Opcodes.DUP);
super.visitMethodInsn(Opcodes.INVOKESTATIC, TARGET_STATIC_CLASS,
TARGET_STATIC_METHOD_NAME, TARGET_STATIC_METHOD_DESC);
}
}
}
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