//
// Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// UnfoldShortCircuitAST is an AST traverser to replace short-circuiting
// operations with ternary operations.
//

#ifndef COMPILER_UNFOLD_SHORT_CIRCUIT_AST_H_
#define COMPILER_UNFOLD_SHORT_CIRCUIT_AST_H_

#include "common/angleutils.h"
#include "compiler/intermediate.h"

// This traverser identifies all the short circuit binary  nodes that need to
// be replaced, and creates the corresponding replacement nodes. However,
// the actual replacements happen after the traverse through updateTree().

class UnfoldShortCircuitAST : public TIntermTraverser
{
  public:
    UnfoldShortCircuitAST() { }

    virtual bool visitBinary(Visit visit, TIntermBinary *);

    void updateTree();

  private:
    struct NodeUpdateEntry
    {
        NodeUpdateEntry(TIntermNode *_parent,
                        TIntermNode *_original,
                        TIntermNode *_replacement)
            : parent(_parent),
              original(_original),
              replacement(_replacement) {}

        TIntermNode *parent;
        TIntermNode *original;
        TIntermNode *replacement;
    };

    // During traversing, save all the replacements that need to happen;
    // then replace them by calling updateNodes().
    std::vector<NodeUpdateEntry> replacements;

    DISALLOW_COPY_AND_ASSIGN(UnfoldShortCircuitAST);
};

#endif  // COMPILER_UNFOLD_SHORT_CIRCUIT_AST_H_
