/*
    *  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.commons.compress.harmony.pack200;
  
  import org.objectweb.asm.Attribute;
  import org.objectweb.asm.ClassReader;
  import org.objectweb.asm.Label;
  
  /**
   * NewAttribute extends {@code Attribute} and manages unknown attributes encountered by ASM that have had a layout definition given to pack200 (e.g. via one of
   * the -C, -M, -F or -D command line options)
   */
  public class NewAttribute extends Attribute {
  
      /**
       * ErrorAttribute extends {@code NewAttribute} and manages attributes encountered by ASM that have had an error action specified to pack200 (e.g. via one of
       * the -C, -M, -F or -D command line options such as -Cattribute-name=error)
       */
      public static class ErrorAttribute extends NewAttribute {
  
          public ErrorAttribute(final String type, final int context) {
              super(type, "", context);
          }
  
          @Override
          protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) {
              throw new Error("Attribute " + type + " was found");
          }
  
      }
  
      /**
       * PassAttribute extends {@code NewAttribute} and manages attributes encountered by ASM that have had a pass action specified to pack200 (e.g. via one of
       * the -C, -M, -F or -D command line options such as -Cattribute-name=pass)
       */
      public static class PassAttribute extends NewAttribute {
  
          public PassAttribute(final String type, final int context) {
              super(type, "", context);
          }
  
          @Override
          protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) {
              throw new Segment.PassException();
          }
  
      }
  
      /**
       * StripAttribute extends {@code NewAttribute} and manages attributes encountered by ASM that have had a strip action specified to pack200 (e.g. via one of
       * the -C, -M, -F or -D command line options such as -Cattribute-name=strip)
       */
      public static class StripAttribute extends NewAttribute {
  
          public StripAttribute(final String type, final int context) {
              super(type, "", context);
          }
  
          @Override
          protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) {
              // TODO Not sure if this works, can we really strip an attribute if we don't know the layout?
              return null;
          }
      }
  
      private boolean contextClass;
  
      private boolean contextMethod;
      private boolean contextField;
      private boolean contextCode;
      private final String layout;
      private byte[] contents;
      private int codeOff;
  
      private Label[] labels;
  
      private ClassReader classReader;
  
      private char[] buf;
  
      public NewAttribute(final ClassReader classReader, final String type, final String layout, final byte[] contents, final char[] buf, final int codeOff,
              final Label[] labels) {
          super(type);
          this.classReader = classReader;
          this.contents = contents;
         this.layout = layout;
         this.codeOff = codeOff;
         this.labels = labels;
         this.buf = buf;
     }
 
     public NewAttribute(final String type, final String layout, final int context) {
         super(type);
         this.layout = layout;
         addContext(context);
     }
 
     public void addContext(final int context) {
         switch (context) {
         case AttributeDefinitionBands.CONTEXT_CLASS:
             contextClass = true;
             break;
         case AttributeDefinitionBands.CONTEXT_METHOD:
             contextMethod = true;
             break;
         case AttributeDefinitionBands.CONTEXT_FIELD:
             contextField = true;
             break;
         case AttributeDefinitionBands.CONTEXT_CODE:
             contextCode = true;
             break;
         }
     }
 
     public byte[] getBytes() {
         return contents;
     }
 
     public Label getLabel(final int index) {
         return labels[index];
     }
 
     public String getLayout() {
         return layout;
     }
 
     @Override
     public boolean isCodeAttribute() {
         return codeOff != -1;
     }
 
     public boolean isContextClass() {
         return contextClass;
     }
 
     public boolean isContextCode() {
         return contextCode;
     }
 
     public boolean isContextField() {
         return contextField;
     }
 
     public boolean isContextMethod() {
         return contextMethod;
     }
 
     @Override
     public boolean isUnknown() {
         return false;
     }
 
     public boolean isUnknown(final int context) {
         switch (context) {
         case AttributeDefinitionBands.CONTEXT_CLASS:
             return !contextClass;
         case AttributeDefinitionBands.CONTEXT_METHOD:
             return !contextMethod;
         case AttributeDefinitionBands.CONTEXT_FIELD:
             return !contextField;
         case AttributeDefinitionBands.CONTEXT_CODE:
             return !contextCode;
         }
         return false;
     }
 
     @Override
     protected Attribute read(final ClassReader cr, final int off, final int len, final char[] buf, final int codeOff, final Label[] labels) {
         final byte[] attributeContents = new byte[len];
         System.arraycopy(cr.b, off, attributeContents, 0, len);
         return new NewAttribute(cr, type, layout, attributeContents, buf, codeOff, labels);
     }
 
     public String readClass(final int index) {
         return classReader.readClass(index, buf);
     }
 
     public Object readConst(final int index) {
         return classReader.readConst(index, buf);
     }
 
     public String readUTF8(final int index) {
         return classReader.readUTF8(index, buf);
     }
 }