// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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package org.objectweb.asm.commons;

import java.util.Collections;
import java.util.Comparator;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.TryCatchBlockNode;

A MethodVisitor adapter to sort the exception handlers. The handlers are sorted in a method innermost-to-outermost. This allows the programmer to add handlers without worrying about ordering them correctly with respect to existing, in-code handlers. 
Behavior is only defined for properly-nested handlers. If any "try" blocks overlap (something
that isn't possible in Java code) then this may not do what you want. In fact, this adapter just
sorts by the length of the "try" block, taking advantage of the fact that a given try block must
be larger than any block it contains).
Author:
Adrian Sampson/**
 * A {@link MethodVisitor} adapter to sort the exception handlers. The handlers are sorted in a
 * method innermost-to-outermost. This allows the programmer to add handlers without worrying about
 * ordering them correctly with respect to existing, in-code handlers.
 *
 * <p>Behavior is only defined for properly-nested handlers. If any "try" blocks overlap (something
 * that isn't possible in Java code) then this may not do what you want. In fact, this adapter just
 * sorts by the length of the "try" block, taking advantage of the fact that a given try block must
 * be larger than any block it contains).
 *
 * @author Adrian Sampson
 */
public class TryCatchBlockSorter extends MethodNode {

  
Constructs a new TryCatchBlockSorter. 
Params:
methodVisitor – the method visitor to which this visitor must delegate method calls. May be null.
access – the method's access flags (see Opcodes). This parameter also indicates if the method is synthetic and/or deprecated.
name – the method's name.
descriptor – the method's descriptor (see Type).
signature – the method's signature. May be null if the method parameters, return type and exceptions do not use generic types.
exceptions – the internal names of the method's exception classes (see Type.getInternalName()). May be null./**
   * Constructs a new {@link TryCatchBlockSorter}.
   *
   * @param methodVisitor the method visitor to which this visitor must delegate method calls. May
   *     be {@literal null}.
   * @param access the method's access flags (see {@link Opcodes}). This parameter also indicates if
   *     the method is synthetic and/or deprecated.
   * @param name the method's name.
   * @param descriptor the method's descriptor (see {@link org.objectweb.asm.Type}).
   * @param signature the method's signature. May be {@literal null} if the method parameters,
   *     return type and exceptions do not use generic types.
   * @param exceptions the internal names of the method's exception classes (see {@link
   *     org.objectweb.asm.Type#getInternalName()}). May be {@literal null}.
   */
  public TryCatchBlockSorter(
      final MethodVisitor methodVisitor,
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final String[] exceptions) {
    this(Opcodes.ASM7, methodVisitor, access, name, descriptor, signature, exceptions);
    if (getClass() != TryCatchBlockSorter.class) {
      throw new IllegalStateException();
    }
  }

  protected TryCatchBlockSorter(
      final int api,
      final MethodVisitor methodVisitor,
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final String[] exceptions) {
    super(api, access, name, descriptor, signature, exceptions);
    this.mv = methodVisitor;
  }

  @Override
  public void visitEnd() {
    // Sort the TryCatchBlockNode elements by the length of their "try" block.
    Collections.sort(
        tryCatchBlocks,
        new Comparator<TryCatchBlockNode>() {

          @Override
          public int compare(
              final TryCatchBlockNode tryCatchBlockNode1,
              final TryCatchBlockNode tryCatchBlockNode2) {
            return blockLength(tryCatchBlockNode1) - blockLength(tryCatchBlockNode2);
          }

          private int blockLength(final TryCatchBlockNode tryCatchBlockNode) {
            int startIndex = instructions.indexOf(tryCatchBlockNode.start);
            int endIndex = instructions.indexOf(tryCatchBlockNode.end);
            return endIndex - startIndex;
          }
        });
    // Update the 'target' of each try catch block annotation.
    for (int i = 0; i < tryCatchBlocks.size(); ++i) {
      tryCatchBlocks.get(i).updateIndex(i);
    }
    if (mv != null) {
      accept(mv);
    }
  }
}