asio/test/bind_allocator.cpp

//
// bind_allocator.cpp
// ~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

// Disable autolinking for unit tests.
#if !defined(BOOST_ALL_NO_LIB)
#define BOOST_ALL_NO_LIB 1
#endif // !defined(BOOST_ALL_NO_LIB)

// Test that header file is self-contained.
#include <boost/asio/bind_allocator.hpp>

#include <functional>
#include <boost/asio/io_context.hpp>
#include <boost/asio/steady_timer.hpp>
#include "unit_test.hpp"

using namespace boost::asio;
namespace bindns = std;
typedef steady_timer timer;
namespace chronons = boost::asio::chrono;

template <typename T>
class test_allocator
{
public:
  typedef T value_type;

  explicit test_allocator(int* allocations)
    : allocations_(allocations)
  {
  }

  template <typename U>
  test_allocator(const test_allocator<U>& other)
    : allocations_(other.allocations_)
  {
  }

  template <typename U>
  struct rebind
  {
    typedef test_allocator<U> other;
  };

  bool operator==(const test_allocator&) const
  {
    return true;
  }

  bool operator!=(const test_allocator&) const
  {
    return false;
  }

  T* allocate(std::size_t n) const
  {
    ++(*allocations_);
    return static_cast<T*>(::operator new(sizeof(T) * n));
  }

  void deallocate(T* p, std::size_t /*n*/) const
  {
    --(*allocations_);
    ::operator delete(p);
  }

//private:
  int* allocations_;
};

void increment(int* count)
{
  ++(*count);
}

void bind_allocator_to_function_object_test()
{
  io_context ioc;

  int count = 0;
  int allocations = 0;

  timer t(ioc, chronons::seconds(1));
  t.async_wait(
      bind_allocator(
        test_allocator<int>(&allocations),
        bindns::bind(&increment, &count)));

  BOOST_ASIO_CHECK(count == 0);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.run();

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 0);

  t.async_wait(
      bind_allocator(
        test_allocator<int>(&allocations),
        bind_allocator(
          std::allocator<void>(),
          bindns::bind(&increment, &count))));

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.restart();
  ioc.run();

  BOOST_ASIO_CHECK(count == 2);
  BOOST_ASIO_CHECK(allocations == 0);
}

struct incrementer_token_v1
{
  explicit incrementer_token_v1(int* c) : count(c) {}
  int* count;
};

struct incrementer_handler_v1
{
  explicit incrementer_handler_v1(incrementer_token_v1 t) : count(t.count) {}
  void operator()(boost::system::error_code){ increment(count); }
  int* count;
};

namespace boost {
namespace asio {

template <>
class async_result<incrementer_token_v1, void(boost::system::error_code)>
{
public:
  typedef incrementer_handler_v1 completion_handler_type;
  typedef void return_type;
  explicit async_result(completion_handler_type&) {}
  return_type get() {}
};

} // namespace asio
} // namespace boost

void bind_allocator_to_completion_token_v1_test()
{
  io_context ioc;

  int count = 0;
  int allocations = 0;

  timer t(ioc, chronons::seconds(1));
  t.async_wait(
      bind_allocator(
        test_allocator<int>(&allocations),
        incrementer_token_v1(&count)));

  BOOST_ASIO_CHECK(count == 0);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.run();

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 0);
}

struct incrementer_token_v2
{
  explicit incrementer_token_v2(int* c) : count(c) {}
  int* count;
};

namespace boost {
namespace asio {

template <>
class async_result<incrementer_token_v2, void(boost::system::error_code)>
{
public:
#if !defined(BOOST_ASIO_HAS_RETURN_TYPE_DEDUCTION)
  typedef void return_type;
#endif // !defined(BOOST_ASIO_HAS_RETURN_TYPE_DEDUCTION)

  template <typename Initiation, typename... Args>
  static void initiate(Initiation initiation,
      incrementer_token_v2 token, Args&&... args)
  {
    initiation(bindns::bind(&increment, token.count),
        static_cast<Args&&>(args)...);
  }
};

} // namespace asio
} // namespace boost

void bind_allocator_to_completion_token_v2_test()
{
  io_context ioc;

  int count = 0;
  int allocations = 0;

  timer t(ioc, chronons::seconds(1));
  t.async_wait(
      bind_allocator(
        test_allocator<int>(&allocations),
        incrementer_token_v2(&count)));

  BOOST_ASIO_CHECK(count == 0);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.run();

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 0);
}

void partial_bind_allocator_test()
{
  io_context ioc;

  int count = 0;
  int allocations = 0;

  timer t(ioc, chronons::seconds(1));
  t.async_wait(bind_allocator(test_allocator<int>(&allocations)))(
      bindns::bind(&increment, &count));

  BOOST_ASIO_CHECK(count == 0);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.run();

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 0);

  t.expires_after(chronons::seconds(1));
  t.async_wait()(
      bind_allocator(test_allocator<int>(&allocations)))(
        incrementer_token_v2(&count));

  BOOST_ASIO_CHECK(count == 0);
  BOOST_ASIO_CHECK(allocations == 1);

  ioc.restart();
  ioc.run();

  BOOST_ASIO_CHECK(count == 1);
  BOOST_ASIO_CHECK(allocations == 0);
}

BOOST_ASIO_TEST_SUITE
(
  "bind_allocator",
  BOOST_ASIO_TEST_CASE(bind_allocator_to_function_object_test)
  BOOST_ASIO_TEST_CASE(bind_allocator_to_completion_token_v1_test)
  BOOST_ASIO_TEST_CASE(bind_allocator_to_completion_token_v2_test)
)