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Diffstat (limited to 'lib/asio/execution_context.hpp')
| -rw-r--r-- | lib/asio/execution_context.hpp | 411 |
1 files changed, 0 insertions, 411 deletions
diff --git a/lib/asio/execution_context.hpp b/lib/asio/execution_context.hpp deleted file mode 100644 index 1476d19..0000000 --- a/lib/asio/execution_context.hpp +++ /dev/null @@ -1,411 +0,0 @@ -// -// 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 |