org.eclipse.wb.internal.rcp.model.util.ActivatorGetImagesByteCodeProcessor.java Source code

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Here is the source code for org.eclipse.wb.internal.rcp.model.util.ActivatorGetImagesByteCodeProcessor.java

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/*******************************************************************************
 * Copyright (c) 2011 Google, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Google, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.wb.internal.rcp.model.util;

import org.eclipse.wb.internal.core.utils.asm.ToBytesClassAdapter;
import org.eclipse.wb.internal.core.utils.reflect.IByteCodeProcessor;
import org.eclipse.wb.internal.core.utils.reflect.ProjectClassLoader;
import org.eclipse.wb.internal.swt.model.property.editor.image.plugin.WorkspacePluginInfo;

import org.eclipse.core.resources.IProject;

import net.sf.cglib.core.ReflectUtils;

import org.apache.commons.io.IOUtils;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.commons.EmptyVisitor;

import java.io.InputStream;

/**
 * If subclass of {@link org.eclipse.ui.plugin.AbstractUIPlugin} is not runtime plugin (i.e. just
 * project in workspace), its method {@code ImageDescriptor getImageDescriptor(String path)} should
 * by intercepted and implemented to return appropriate ImageDescriptor.
 * 
 * @author lobas_av
 * @coverage rcp.util
 */
public final class ActivatorGetImagesByteCodeProcessor implements IByteCodeProcessor {
    private String m_activatorClassName;
    private String m_activatorProjectPath;

    ////////////////////////////////////////////////////////////////////////////
    //
    // IByteCodeProcessor
    //
    ////////////////////////////////////////////////////////////////////////////
    public void initialize(ProjectClassLoader classLoader) {
        createInternalImageManager(classLoader);
        prepareActivatorInformation(classLoader.getJavaProject().getProject());
    }

    public byte[] process(String className, byte[] bytes) {
        if (className.equals(m_activatorClassName)) {
            return transformActivatorClass(bytes);
        }
        return bytes;
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // Handle
    //
    ////////////////////////////////////////////////////////////////////////////
    private void createInternalImageManager(ProjectClassLoader classLoader) {
        try {
            // prepare InternalImageManager bytes
            ClassLoader localClassLoader = getClass().getClassLoader();
            InputStream stream = localClassLoader
                    .getResourceAsStream("org/eclipse/wb/internal/rcp/model/util/InternalImageManager.class");
            byte[] bytes = IOUtils.toByteArray(stream);
            stream.close();
            // inject InternalImageManager to project class loader
            ReflectUtils.defineClass("org.eclipse.wb.internal.rcp.model.util.InternalImageManager", bytes,
                    classLoader);
        } catch (Throwable e) {
        }
    }

    private void prepareActivatorInformation(IProject project) {
        try {
            m_activatorClassName = WorkspacePluginInfo.getBundleActivator(project);
            m_activatorProjectPath = project.getLocation().toPortableString();
        } catch (Throwable e) {
        }
    }

    private byte[] transformActivatorClass(byte[] bytes) {
        final boolean[] apply = { false };
        ClassReader classReader = new ClassReader(bytes);
        ToBytesClassAdapter codeRewriter = new ToBytesClassAdapter(ClassWriter.COMPUTE_MAXS) {
            @Override
            public MethodVisitor visitMethod(int access, String name, String desc, String signature,
                    String[] exceptions) {
                final MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
                final int pathParameterIndex = (access & ACC_STATIC) != 0 ? 0 : 1;
                // transform Activator.getImageDescriptor()
                if (name.equals("getImageDescriptor")
                        && desc.equals("(Ljava/lang/String;)Lorg/eclipse/jface/resource/ImageDescriptor;")) {
                    apply[0] = true;
                    return new EmptyVisitor() {
                        @Override
                        public void visitCode() {
                            mv.visitLdcInsn(m_activatorProjectPath);
                            mv.visitVarInsn(ALOAD, pathParameterIndex);
                            mv.visitMethodInsn(INVOKESTATIC,
                                    "org/eclipse/wb/internal/rcp/model/util/InternalImageManager",
                                    "getImageDescriptor",
                                    "(Ljava/lang/String;Ljava/lang/String;)Lorg/eclipse/jface/resource/ImageDescriptor;");
                            mv.visitInsn(ARETURN);
                        }

                        @Override
                        public void visitMaxs(int maxStack, int maxLocals) {
                            mv.visitMaxs(maxStack, maxLocals);
                        }
                    };
                }
                // transform Activator.getImage()
                if (name.equals("getImage")
                        && desc.equals("(Ljava/lang/String;)Lorg/eclipse/swt/graphics/Image;")) {
                    apply[0] = true;
                    return new EmptyVisitor() {
                        @Override
                        public void visitCode() {
                            mv.visitLdcInsn(m_activatorProjectPath);
                            mv.visitVarInsn(ALOAD, pathParameterIndex);
                            mv.visitMethodInsn(INVOKESTATIC,
                                    "org/eclipse/wb/internal/rcp/model/util/InternalImageManager", "getImage",
                                    "(Ljava/lang/String;Ljava/lang/String;)Lorg/eclipse/swt/graphics/Image;");
                            mv.visitInsn(ARETURN);
                        }

                        @Override
                        public void visitMaxs(int maxStack, int maxLocals) {
                            mv.visitMaxs(maxStack, maxLocals);
                        }
                    };
                }
                return mv;
            }
        };
        classReader.accept(codeRewriter, 0);
        return apply[0] ? codeRewriter.toByteArray() : bytes;
    }
}