/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.maven.shared.dependency.analyzer.asm;
  
  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;
  import org.objectweb.asm.signature.SignatureReader;
  import org.objectweb.asm.signature.SignatureVisitor;
  
  /**
   * Computes the set of classes referenced by visited code.
   * Inspired by <code>org.objectweb.asm.depend.DependencyVisitor</code> in the ASM dependencies example.
   *
   * @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>
   */
  public class DefaultClassVisitor extends ClassVisitor {
      private final ResultCollector resultCollector;
  
      private final SignatureVisitor signatureVisitor;
  
      private final AnnotationVisitor annotationVisitor;
  
      private final FieldVisitor fieldVisitor;
  
      private final MethodVisitor methodVisitor;
  
      private final String usedByClass;
  
      /**
       * <p>Constructor for DefaultClassVisitor.</p>
       *
       * @param signatureVisitor a {@link org.objectweb.asm.signature.SignatureVisitor} object.
       * @param annotationVisitor a {@link org.objectweb.asm.AnnotationVisitor} object.
       * @param fieldVisitor a {@link org.objectweb.asm.FieldVisitor} object.
       * @param methodVisitor a {@link org.objectweb.asm.MethodVisitor} object.
       * @param resultCollector a {@link org.apache.maven.shared.dependency.analyzer.asm.ResultCollector} object.
       */
      public DefaultClassVisitor(
              SignatureVisitor signatureVisitor,
              AnnotationVisitor annotationVisitor,
              FieldVisitor fieldVisitor,
              MethodVisitor methodVisitor,
              ResultCollector resultCollector,
              String usedByClass) {
          super(Opcodes.ASM9);
          this.signatureVisitor = signatureVisitor;
          this.annotationVisitor = annotationVisitor;
          this.fieldVisitor = fieldVisitor;
          this.methodVisitor = methodVisitor;
          this.resultCollector = resultCollector;
          this.usedByClass = usedByClass;
      }
  
      /**
       * <p>visit.</p>
       *
       * @param version a int.
       * @param access a int.
       * @param name a {@link java.lang.String} object.
       * @param signature a {@link java.lang.String} object.
       * @param superName a {@link java.lang.String} object.
       * @param interfaces an array of {@link java.lang.String} objects.
       */
      @Override
      public void visit(
              final int version,
              final int access,
              final String name,
              final String signature,
              final String superName,
              final String[] interfaces) {
          if (signature == null) {
              resultCollector.addName(usedByClass, superName);
              resultCollector.addNames(usedByClass, interfaces);
          } else {
              addSignature(signature);
          }
      }
  
     /** {@inheritDoc} */
     @Override
     public AnnotationVisitor visitAnnotation(final String desc, final boolean visible) {
         resultCollector.addDesc(usedByClass, desc);
 
         return annotationVisitor;
     }
 
     /** {@inheritDoc} */
     @Override
     public FieldVisitor visitField(
             final int access, final String name, final String desc, final String signature, final Object value) {
         if (signature == null) {
             resultCollector.addDesc(usedByClass, desc);
         } else {
             addTypeSignature(signature);
         }
 
         if (value instanceof Type) {
             resultCollector.addType(usedByClass, (Type) value);
         }
 
         return fieldVisitor;
     }
 
     /**
      * <p>visitMethod.</p>
      *
      * @param access a int.
      * @param name a {@link java.lang.String} object.
      * @param desc a {@link java.lang.String} object.
      * @param signature a {@link java.lang.String} object.
      * @param exceptions an array of {@link java.lang.String} objects.
      * @return a {@link org.objectweb.asm.MethodVisitor} object.
      */
     @Override
     public MethodVisitor visitMethod(
             final int access, final String name, final String desc, final String signature, final String[] exceptions) {
         if (signature == null) {
             resultCollector.addMethodDesc(usedByClass, desc);
         } else {
             addSignature(signature);
         }
 
         resultCollector.addNames(usedByClass, exceptions);
 
         return methodVisitor;
     }
 
     /** {@inheritDoc} */
     @Override
     public void visitNestHost(final String nestHost) {
         resultCollector.addName(usedByClass, nestHost);
     }
 
     /** {@inheritDoc} */
     @Override
     public void visitNestMember(final String nestMember) {
         resultCollector.addName(usedByClass, nestMember);
     }
 
     private void addSignature(final String signature) {
         if (signature != null) {
             new SignatureReader(signature).accept(signatureVisitor);
         }
     }
 
     private void addTypeSignature(final String signature) {
         if (signature != null) {
             new SignatureReader(signature).acceptType(signatureVisitor);
         }
     }
 }