/*******************************************************************************
 * Copyright (c) 2008, 2010 VMware 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:
 *   VMware Inc. - initial contribution
 *******************************************************************************/

package org.eclipse.virgo.bundlor.support.asm;

import org.eclipse.virgo.bundlor.support.partialmanifest.PartialManifest;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

/**
 * ASM {@link ClassVisitor} for scanning class files.
 * <p/>
 * 
 * <strong>Concurrent Semantics</strong><br />
 * 
 * Not threadsafe.
 * 
 * @author Rob Harrop
 */
final class ArtifactAnalyzerClassVisitor extends ClassVisitor {

    private static final String CLASS_NAME_PREFIX = "class$";

    /**
     * That <code>PartialManifest</code> being updated.
     */
    private final PartialManifest partialManifest;

    /**
     * The type that is being scanned.
     */
    private Type type;

    /**
     * Creates a new <code>ArtefactAnalyserClassVisitor</code> to scan the supplied {@link PartialManifest}.
     * 
     * @param partialManifest the <code>PartialManifest</code> to scan.
     */
    public ArtifactAnalyzerClassVisitor(PartialManifest partialManifest) {
    	super(Opcodes.ASM5);
        this.partialManifest = partialManifest;
    }

    /**
     * @inheritDoc
     */
    @Override
    public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
        Type type = Type.getObjectType(name);
        this.type = type;

        this.partialManifest.recordType(VisitorUtils.getFullyQualifiedTypeName(type));

        VisitorUtils.recordReferencedTypes(this.partialManifest, Type.getObjectType(superName));
        VisitorUtils.recordUses(this.partialManifest, type, Type.getObjectType(superName));
        for (String interfaceName : interfaces) {
            VisitorUtils.recordReferencedTypes(this.partialManifest, Type.getObjectType(interfaceName));
            VisitorUtils.recordUses(this.partialManifest, type, Type.getObjectType(interfaceName));
        }
    }

    /**
     * @inheritDoc
     */
    @Override
    public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
        Type t = Type.getType(desc);
        VisitorUtils.recordReferencedTypes(this.partialManifest, t);
        VisitorUtils.recordUses(this.partialManifest, this.type, t);
        return null;
    }

    /**
     * @inheritDoc
     */
    @Override
    public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
        Type t = Type.getType(desc);
        if ((access & Opcodes.ACC_SYNTHETIC) == Opcodes.ACC_SYNTHETIC) {
            if (Class.class.getName().equals(t.getClassName())) {
                if (name != null && name.startsWith(CLASS_NAME_PREFIX)) {
                    name = name.substring(CLASS_NAME_PREFIX.length());
                    name = name.replace('$', '.');
                    int lastDotIndex = name.lastIndexOf('.');

                    for (int i = 0; i < lastDotIndex; i++) {
                        if (Character.isUpperCase(name.charAt(i))) {
                            if (i == 0) {
                                return null;
                            }
                            if (name.charAt(i - 1) == '.') {
                                name = name.substring(0, i) + name.substring(i).replace('.', '$');
                                break;
                            }
                        }
                    }
                    if (Character.isJavaIdentifierStart(name.charAt(0))) {
                        this.partialManifest.recordReferencedType(name);
                    }
                }
            }
        }
        VisitorUtils.recordReferencedTypes(this.partialManifest, t);
        return new ArtifactAnalyzerFieldVisitor(this.partialManifest, this.type);
    }

    /**
     * @inheritDoc
     */
    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        VisitorUtils.recordReferencedTypes(this.partialManifest, Type.getArgumentTypes(desc));
        VisitorUtils.recordReferencedTypes(this.partialManifest, Type.getReturnType(desc));
        if (exceptions != null) {
            for (String exception : exceptions) {
                VisitorUtils.recordReferencedTypes(this.partialManifest, Type.getObjectType(exception));
            }
        }
        if (access != Opcodes.ACC_PRIVATE) {
            VisitorUtils.recordUses(this.partialManifest, this.type, Type.getArgumentTypes(desc));
            VisitorUtils.recordUses(this.partialManifest, this.type, Type.getReturnType(desc));
            if (exceptions != null) {
                for (String exception : exceptions) {
                    VisitorUtils.recordUses(this.partialManifest, this.type, Type.getObjectType(exception));
                }
            }
        }
        return new ArtifactAnalyzerMethodVisitor(this.partialManifest, this.type);
    }

}