Replace boost by the standalone asio library

1 files changed, 411 insertions, 0 deletions

diff --git a/lib/asio/execution_context.hpp b/lib/asio/execution_context.hpp
new file mode 100644
index 0000000..1476d19
--- /dev/null
+++ b/lib/asio/execution_context.hpp
@@ -0,0 +1,411 @@
+//
+// execution_context.hpp
+// ~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 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)
+//
+
+#ifndef ASIO_EXECUTION_CONTEXT_HPP
+#define ASIO_EXECUTION_CONTEXT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <cstddef>
+#include <stdexcept>
+#include <typeinfo>
+#include "asio/detail/noncopyable.hpp"
+#include "asio/detail/variadic_templates.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+class execution_context;
+class io_context;
+
+#if !defined(GENERATING_DOCUMENTATION)
+template <typename Service> Service& use_service(execution_context&);
+template <typename Service> Service& use_service(io_context&);
+template <typename Service> void add_service(execution_context&, Service*);
+template <typename Service> bool has_service(execution_context&);
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+namespace detail { class service_registry; }
+
+/// A context for function object execution.
+/**
+ * An execution context represents a place where function objects will be
+ * executed. An @c io_context is an example of an execution context.
+ *
+ * @par The execution_context class and services
+ *
+ * Class execution_context implements an extensible, type-safe, polymorphic set
+ * of services, indexed by service type.
+ *
+ * Services exist to manage the resources that are shared across an execution
+ * context. For example, timers may be implemented in terms of a single timer
+ * queue, and this queue would be stored in a service.
+ *
+ * Access to the services of an execution_context is via three function
+ * templates, use_service(), add_service() and has_service().
+ *
+ * In a call to @c use_service<Service>(), the type argument chooses a service,
+ * making available all members of the named type. If @c Service is not present
+ * in an execution_context, an object of type @c Service is created and added
+ * to the execution_context. A C++ program can check if an execution_context
+ * implements a particular service with the function template @c
+ * has_service<Service>().
+ *
+ * Service objects may be explicitly added to an execution_context using the
+ * function template @c add_service<Service>(). If the @c Service is already
+ * present, the service_already_exists exception is thrown. If the owner of the
+ * service is not the same object as the execution_context parameter, the
+ * invalid_service_owner exception is thrown.
+ *
+ * Once a service reference is obtained from an execution_context object by
+ * calling use_service(), that reference remains usable as long as the owning
+ * execution_context object exists.
+ *
+ * All service implementations have execution_context::service as a public base
+ * class. Custom services may be implemented by deriving from this class and
+ * then added to an execution_context using the facilities described above.
+ *
+ * @par The execution_context as a base class
+ *
+ * Class execution_context may be used only as a base class for concrete
+ * execution context types. The @c io_context is an example of such a derived
+ * type.
+ *
+ * On destruction, a class that is derived from execution_context must perform
+ * <tt>execution_context::shutdown()</tt> followed by
+ * <tt>execution_context::destroy()</tt>.
+ *
+ * This destruction sequence permits programs to simplify their resource
+ * management by using @c shared_ptr<>. Where an object's lifetime is tied to
+ * the lifetime of a connection (or some other sequence of asynchronous
+ * operations), a @c shared_ptr to the object would be bound into the handlers
+ * for all asynchronous operations associated with it. This works as follows:
+ *
+ * @li When a single connection ends, all associated asynchronous operations
+ * complete. The corresponding handler objects are destroyed, and all @c
+ * shared_ptr references to the objects are destroyed.
+ *
+ * @li To shut down the whole program, the io_context function stop() is called
+ * to terminate any run() calls as soon as possible. The io_context destructor
+ * calls @c shutdown() and @c destroy() to destroy all pending handlers,
+ * causing all @c shared_ptr references to all connection objects to be
+ * destroyed.
+ */
+class execution_context
+  : private noncopyable
+{
+public:
+  class id;
+  class service;
+
+protected:
+  /// Constructor.
+  ASIO_DECL execution_context();
+
+  /// Destructor.
+  ASIO_DECL ~execution_context();
+
+  /// Shuts down all services in the context.
+  /**
+   * This function is implemented as follows:
+   *
+   * @li For each service object @c svc in the execution_context set, in
+   * reverse order of the beginning of service object lifetime, performs @c
+   * svc->shutdown().
+   */
+  ASIO_DECL void shutdown();
+
+  /// Destroys all services in the context.
+  /**
+   * This function is implemented as follows:
+   *
+   * @li For each service object @c svc in the execution_context set, in
+   * reverse order * of the beginning of service object lifetime, performs
+   * <tt>delete static_cast<execution_context::service*>(svc)</tt>.
+   */
+  ASIO_DECL void destroy();
+
+public:
+  /// Fork-related event notifications.
+  enum fork_event
+  {
+    /// Notify the context that the process is about to fork.
+    fork_prepare,
+
+    /// Notify the context that the process has forked and is the parent.
+    fork_parent,
+
+    /// Notify the context that the process has forked and is the child.
+    fork_child
+  };
+
+  /// Notify the execution_context of a fork-related event.
+  /**
+   * This function is used to inform the execution_context that the process is
+   * about to fork, or has just forked. This allows the execution_context, and
+   * the services it contains, to perform any necessary housekeeping to ensure
+   * correct operation following a fork.
+   *
+   * This function must not be called while any other execution_context
+   * function, or any function associated with the execution_context's derived
+   * class, is being called in another thread. It is, however, safe to call
+   * this function from within a completion handler, provided no other thread
+   * is accessing the execution_context or its derived class.
+   *
+   * @param event A fork-related event.
+   *
+   * @throws asio::system_error Thrown on failure. If the notification
+   * fails the execution_context object should no longer be used and should be
+   * destroyed.
+   *
+   * @par Example
+   * The following code illustrates how to incorporate the notify_fork()
+   * function:
+   * @code my_execution_context.notify_fork(execution_context::fork_prepare);
+   * if (fork() == 0)
+   * {
+   *   // This is the child process.
+   *   my_execution_context.notify_fork(execution_context::fork_child);
+   * }
+   * else
+   * {
+   *   // This is the parent process.
+   *   my_execution_context.notify_fork(execution_context::fork_parent);
+   * } @endcode
+   *
+   * @note For each service object @c svc in the execution_context set,
+   * performs <tt>svc->notify_fork();</tt>. When processing the fork_prepare
+   * event, services are visited in reverse order of the beginning of service
+   * object lifetime. Otherwise, services are visited in order of the beginning
+   * of service object lifetime.
+   */
+  ASIO_DECL void notify_fork(fork_event event);
+
+  /// Obtain the service object corresponding to the given type.
+  /**
+   * This function is used to locate a service object that corresponds to the
+   * given service type. If there is no existing implementation of the service,
+   * then the execution_context will create a new instance of the service.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @return The service interface implementing the specified service type.
+   * Ownership of the service interface is not transferred to the caller.
+   */
+  template <typename Service>
+  friend Service& use_service(execution_context& e);
+
+  /// Obtain the service object corresponding to the given type.
+  /**
+   * This function is used to locate a service object that corresponds to the
+   * given service type. If there is no existing implementation of the service,
+   * then the io_context will create a new instance of the service.
+   *
+   * @param ioc The io_context object that owns the service.
+   *
+   * @return The service interface implementing the specified service type.
+   * Ownership of the service interface is not transferred to the caller.
+   *
+   * @note This overload is preserved for backwards compatibility with services
+   * that inherit from io_context::service.
+   */
+  template <typename Service>
+  friend Service& use_service(io_context& ioc);
+
+#if defined(GENERATING_DOCUMENTATION)
+
+  /// Creates a service object and adds it to the execution_context.
+  /**
+   * This function is used to add a service to the execution_context.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @param args Zero or more arguments to be passed to the service
+   * constructor.
+   *
+   * @throws asio::service_already_exists Thrown if a service of the
+   * given type is already present in the execution_context.
+   */
+  template <typename Service, typename... Args>
+  friend Service& make_service(execution_context& e, Args&&... args);
+
+#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Service, typename... Args>
+  friend Service& make_service(execution_context& e,
+      ASIO_MOVE_ARG(Args)... args);
+
+#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  template <typename Service>
+  friend Service& make_service(execution_context& e);
+
+#define ASIO_PRIVATE_MAKE_SERVICE_DEF(n) \
+  template <typename Service, ASIO_VARIADIC_TPARAMS(n)> \
+  friend Service& make_service(execution_context& e, \
+      ASIO_VARIADIC_MOVE_PARAMS(n)); \
+  /**/
+  ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_MAKE_SERVICE_DEF)
+#undef ASIO_PRIVATE_MAKE_SERVICE_DEF
+
+#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
+
+  /// (Deprecated: Use make_service().) Add a service object to the
+  /// execution_context.
+  /**
+   * This function is used to add a service to the execution_context.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @param svc The service object. On success, ownership of the service object
+   * is transferred to the execution_context. When the execution_context object
+   * is destroyed, it will destroy the service object by performing: @code
+   * delete static_cast<execution_context::service*>(svc) @endcode
+   *
+   * @throws asio::service_already_exists Thrown if a service of the
+   * given type is already present in the execution_context.
+   *
+   * @throws asio::invalid_service_owner Thrown if the service's owning
+   * execution_context is not the execution_context object specified by the
+   * @c e parameter.
+   */
+  template <typename Service>
+  friend void add_service(execution_context& e, Service* svc);
+
+  /// Determine if an execution_context contains a specified service type.
+  /**
+   * This function is used to determine whether the execution_context contains a
+   * service object corresponding to the given service type.
+   *
+   * @param e The execution_context object that owns the service.
+   *
+   * @return A boolean indicating whether the execution_context contains the
+   * service.
+   */
+  template <typename Service>
+  friend bool has_service(execution_context& e);
+
+private:
+  // The service registry.
+  asio::detail::service_registry* service_registry_;
+};
+
+/// Class used to uniquely identify a service.
+class execution_context::id
+  : private noncopyable
+{
+public:
+  /// Constructor.
+  id() {}
+};
+
+/// Base class for all io_context services.
+class execution_context::service
+  : private noncopyable
+{
+public:
+  /// Get the context object that owns the service.
+  execution_context& context();
+
+protected:
+  /// Constructor.
+  /**
+   * @param owner The execution_context object that owns the service.
+   */
+  ASIO_DECL service(execution_context& owner);
+
+  /// Destructor.
+  ASIO_DECL virtual ~service();
+
+private:
+  /// Destroy all user-defined handler objects owned by the service.
+  virtual void shutdown() = 0;
+
+  /// Handle notification of a fork-related event to perform any necessary
+  /// housekeeping.
+  /**
+   * This function is not a pure virtual so that services only have to
+   * implement it if necessary. The default implementation does nothing.
+   */
+  ASIO_DECL virtual void notify_fork(
+      execution_context::fork_event event);
+
+  friend class asio::detail::service_registry;
+  struct key
+  {
+    key() : type_info_(0), id_(0) {}
+    const std::type_info* type_info_;
+    const execution_context::id* id_;
+  } key_;
+
+  execution_context& owner_;
+  service* next_;
+};
+
+/// Exception thrown when trying to add a duplicate service to an
+/// execution_context.
+class service_already_exists
+  : public std::logic_error
+{
+public:
+  ASIO_DECL service_already_exists();
+};
+
+/// Exception thrown when trying to add a service object to an
+/// execution_context where the service has a different owner.
+class invalid_service_owner
+  : public std::logic_error
+{
+public:
+  ASIO_DECL invalid_service_owner();
+};
+
+namespace detail {
+
+// Special derived service id type to keep classes header-file only.
+template <typename Type>
+class service_id
+  : public execution_context::id
+{
+};
+
+// Special service base class to keep classes header-file only.
+template <typename Type>
+class execution_context_service_base
+  : public execution_context::service
+{
+public:
+  static service_id<Type> id;
+
+  // Constructor.
+  execution_context_service_base(execution_context& e)
+    : execution_context::service(e)
+  {
+  }
+};
+
+template <typename Type>
+service_id<Type> execution_context_service_base<Type>::id;
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/impl/execution_context.hpp"
+#if defined(ASIO_HEADER_ONLY)
+# include "asio/impl/execution_context.ipp"
+#endif // defined(ASIO_HEADER_ONLY)
+
+#endif // ASIO_EXECUTION_CONTEXT_HPP