text: /*
     +----------------------------------------------------------------------+
     | HipHop for PHP                                                       |
     +----------------------------------------------------------------------+
     | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
     +----------------------------------------------------------------------+
     | This source file is subject to version 3.01 of the PHP license,      |
     | that is bundled with this package in the file LICENSE, and is        |
     | available through the world-wide-web at the following url:           |
     | http://www.php.net/license/3_01.txt                                  |
     | If you did not receive a copy of the PHP license and are unable to   |
     | obtain it through the world-wide-web, please send a note to          |
     | license@php.net so we can mail you a copy immediately.               |
     +----------------------------------------------------------------------+
  */
  
  #pragma once
  
  #include <folly/dynamic.h>
  
  #include <cstdint>
  
  namespace HPHP {
  
  struct ArrayData;
  
  namespace jit {
  
  ///////////////////////////////////////////////////////////////////////////////
  
  // Profile whether an array could need to COW before a mutation
  struct COWProfile {
  
    enum class Result {
      AlwaysCOW = 0,
      UsuallyCOW,
      None,
      RarelyCOW,
      NeverCOW
    };
  
    Result choose() const;
  
    void update(const ArrayData* ad);
  
    static void reduce(COWProfile& l, const COWProfile& r);
  
    std::string toString() const;
    folly::dynamic toDynamic() const;
  
  private:
    uint64_t m_nocow{0};
    uint64_t m_total{0};
  };
  
  ///////////////////////////////////////////////////////////////////////////////
  
  }}
  