cpw.mods.fml.common.asm.transformers.SideTransformer.java Source code

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Here is the source code for cpw.mods.fml.common.asm.transformers.SideTransformer.java

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/*
 * Forge Mod Loader
 * Copyright (c) 2012-2013 cpw.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser Public License v2.1
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 *
 * Contributors:
 *     cpw - implementation
 */

package cpw.mods.fml.common.asm.transformers;

import java.util.Iterator;
import java.util.List;

import net.minecraft.launchwrapper.IClassTransformer;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AnnotationNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldNode;
import org.objectweb.asm.tree.MethodNode;

import cpw.mods.fml.relauncher.FMLLaunchHandler;
import cpw.mods.fml.relauncher.SideOnly;

public class SideTransformer implements IClassTransformer {
    private static String SIDE = FMLLaunchHandler.side().name();
    private static final boolean DEBUG = false;

    @Override
    public byte[] transform(String name, String transformedName, byte[] bytes) {
        if (bytes == null) {
            return null;
        }

        ClassNode classNode = new ClassNode();
        ClassReader classReader = new ClassReader(bytes);
        classReader.accept(classNode, 0);

        if (remove((List<AnnotationNode>) classNode.visibleAnnotations, SIDE)) {
            if (DEBUG) {
                System.out.println(
                        String.format("Attempted to load class %s for invalid side %s", classNode.name, SIDE));
            }
            throw new RuntimeException(
                    String.format("Attempted to load class %s for invalid side %s", classNode.name, SIDE));
        }

        Iterator<FieldNode> fields = classNode.fields.iterator();
        while (fields.hasNext()) {
            FieldNode field = fields.next();
            if (remove((List<AnnotationNode>) field.visibleAnnotations, SIDE)) {
                if (DEBUG) {
                    System.out.println(String.format("Removing Field: %s.%s", classNode.name, field.name));
                }
                fields.remove();
            }
        }
        Iterator<MethodNode> methods = classNode.methods.iterator();
        while (methods.hasNext()) {
            MethodNode method = methods.next();
            if (remove((List<AnnotationNode>) method.visibleAnnotations, SIDE)) {
                if (DEBUG) {
                    System.out.println(
                            String.format("Removing Method: %s.%s%s", classNode.name, method.name, method.desc));
                }
                methods.remove();
            }
        }

        ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS);
        classNode.accept(writer);
        return writer.toByteArray();
    }

    private boolean remove(List<AnnotationNode> anns, String side) {
        if (anns == null) {
            return false;
        }
        for (AnnotationNode ann : anns) {
            if (ann.desc.equals(Type.getDescriptor(SideOnly.class))) {
                if (ann.values != null) {
                    for (int x = 0; x < ann.values.size() - 1; x += 2) {
                        Object key = ann.values.get(x);
                        Object value = ann.values.get(x + 1);
                        if (key instanceof String && key.equals("value")) {
                            if (value instanceof String[]) {
                                if (!((String[]) value)[1].equals(side)) {
                                    return true;
                                }
                            }
                        }
                    }
                }
            }
        }
        return false;
    }
}