Initial Commit

include/asio/detail/impl/service_registry.ipp

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+//
+// detail/impl/service_registry.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// 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)
+//
+
+#ifndef ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP
+#define ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <vector>
+#include "asio/detail/service_registry.hpp"
+#include "asio/detail/throw_exception.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+service_registry::service_registry(execution_context& owner)
+  : owner_(owner),
+    first_service_(0)
+{
+}
+
+service_registry::~service_registry()
+{
+}
+
+void service_registry::shutdown_services()
+{
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    service->shutdown();
+    service = service->next_;
+  }
+}
+
+void service_registry::destroy_services()
+{
+  while (first_service_)
+  {
+    execution_context::service* next_service = first_service_->next_;
+    first_service_->destroy_(first_service_);
+    first_service_ = next_service;
+  }
+}
+
+void service_registry::notify_fork(execution_context::fork_event fork_ev)
+{
+  // Make a copy of all of the services while holding the lock. We don't want
+  // to hold the lock while calling into each service, as it may try to call
+  // back into this class.
+  std::vector<execution_context::service*> services;
+  {
+    asio::detail::mutex::scoped_lock lock(mutex_);
+    execution_context::service* service = first_service_;
+    while (service)
+    {
+      services.push_back(service);
+      service = service->next_;
+    }
+  }
+
+  // If processing the fork_prepare event, we want to go in reverse order of
+  // service registration, which happens to be the existing order of the
+  // services in the vector. For the other events we want to go in the other
+  // direction.
+  std::size_t num_services = services.size();
+  if (fork_ev == execution_context::fork_prepare)
+    for (std::size_t i = 0; i < num_services; ++i)
+      services[i]->notify_fork(fork_ev);
+  else
+    for (std::size_t i = num_services; i > 0; --i)
+      services[i - 1]->notify_fork(fork_ev);
+}
+
+void service_registry::init_key_from_id(execution_context::service::key& key,
+    const execution_context::id& id)
+{
+  key.type_info_ = 0;
+  key.id_ = &id;
+}
+
+bool service_registry::keys_match(
+    const execution_context::service::key& key1,
+    const execution_context::service::key& key2)
+{
+  if (key1.id_ && key2.id_)
+    if (key1.id_ == key2.id_)
+      return true;
+  if (key1.type_info_ && key2.type_info_)
+    if (*key1.type_info_ == *key2.type_info_)
+      return true;
+  return false;
+}
+
+void service_registry::destroy_added(execution_context::service* service)
+{
+  delete service;
+}
+
+service_registry::auto_service_ptr::~auto_service_ptr()
+{
+  if (ptr_)
+    ptr_->destroy_(ptr_);
+}
+
+execution_context::service* service_registry::do_use_service(
+    const execution_context::service::key& key,
+    factory_type factory, void* owner)
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // First see if there is an existing service object with the given key.
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return service;
+    service = service->next_;
+  }
+
+  // Create a new service object. The service registry's mutex is not locked
+  // at this time to allow for nested calls into this function from the new
+  // service's constructor.
+  lock.unlock();
+  auto_service_ptr new_service = { factory(owner_, owner) };
+  new_service.ptr_->key_ = key;
+  lock.lock();
+
+  // Check that nobody else created another service object of the same type
+  // while the lock was released.
+  service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return service;
+    service = service->next_;
+  }
+
+  // Service was successfully initialised, pass ownership to registry.
+  new_service.ptr_->next_ = first_service_;
+  first_service_ = new_service.ptr_;
+  new_service.ptr_ = 0;
+  return first_service_;
+}
+
+void service_registry::do_add_service(
+    const execution_context::service::key& key,
+    execution_context::service* new_service)
+{
+  if (&owner_ != &new_service->context())
+    asio::detail::throw_exception(invalid_service_owner());
+
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  // Check if there is an existing service object with the given key.
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      asio::detail::throw_exception(service_already_exists());
+    service = service->next_;
+  }
+
+  // Take ownership of the service object.
+  if (!new_service->destroy_)
+    new_service->destroy_ = &service_registry::destroy_added;
+  new_service->key_ = key;
+  new_service->next_ = first_service_;
+  first_service_ = new_service;
+}
+
+bool service_registry::do_has_service(
+    const execution_context::service::key& key) const
+{
+  asio::detail::mutex::scoped_lock lock(mutex_);
+
+  execution_context::service* service = first_service_;
+  while (service)
+  {
+    if (keys_match(service->key_, key))
+      return true;
+    service = service->next_;
+  }
+
+  return false;
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_IMPL_SERVICE_REGISTRY_IPP