device-registry.h

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2015-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#ifndef CMSIS_PLUS_POSIX_IO_DEVICE_REGISTRY_H_
#define CMSIS_PLUS_POSIX_IO_DEVICE_REGISTRY_H_
 
// ----------------------------------------------------------------------------
 
#if defined(__cplusplus)
 
// ----------------------------------------------------------------------------
 
#if defined(OS_USE_OS_APP_CONFIG_H)
#include <cmsis-plus/os-app-config.h>
#endif
 
#include <cmsis-plus/posix-io/device.h>
#include <cmsis-plus/diag/trace.h>
 
#include <cstddef>
#include <cassert>
#include <cstring>
 
// ----------------------------------------------------------------------------
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#endif
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace posix
  {
    // ========================================================================
 
    template <typename T>
    class device_registry
    {
    public:
      using value_type = T;
      using pointer = T*;
      using reference = T&;
 
      // ----------------------------------------------------------------------
 
    public:
      // Do not allow to create instances of this class.
      device_registry () = delete;
 
      // The rule of five.
      device_registry (const value_type&) = delete;
      device_registry (value_type&&) = delete;
      value_type&
      operator= (const value_type&)
          = delete;
      value_type&
      operator= (value_type&&)
          = delete;
 
      ~device_registry () = delete;
 
      // ----------------------------------------------------------------------
    public:
      static void
      link (value_type* device);
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"
#endif
      static value_type*
      identify_device (const char* path);
#pragma GCC diagnostic pop
 
      // ----------------------------------------------------------------------
    private:
      // Since devices may be constructed statically, so may ask
      // to be linked here at any time, this list must be initialised
      // before any static constructor.
      // With the order of static constructors unknown, this means it
      // must be allocated in the BSS and will be initialised to 0 by
      // the startup code.
      using device_list
          = utils::intrusive_list<device, utils::double_list_links,
                                  &device::registry_links_, T>;
      static device_list registry_list__;
 
    };
 
    // ========================================================================
  } /* namespace posix */
} /* namespace os */
 
// ===== Inline & template implementations ====================================
 
namespace os
{
  namespace posix
  {
    // ========================================================================
 
    template <typename T>
    void
    device_registry<T>::link (value_type* device)
    {
#if defined(DEBUG)
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Waggregate-return"
#endif
      for (auto&& d : registry_list__)
        {
          // Validate the device name by checking duplicates.
          if (std::strcmp (device->name (), d.name ()) == 0)
            {
              trace::puts ("Duplicate device name. Abort.");
              std::abort ();
            }
        }
#pragma GCC diagnostic push
 
#endif // DEBUG
 
      registry_list__.link (*device);
 
      trace::printf ("Device '%s%s' linked\n", value_type::device_prefix (),
                     device->name ());
    }
 
    template <typename T>
    T*
    device_registry<T>::identify_device (const char* path)
    {
      assert (path != nullptr);
 
      auto prefix = value_type::device_prefix ();
      if (std::strncmp (prefix, path, std::strlen (prefix)) != 0)
        {
          // The device prefix does not match, not a device.
          return nullptr;
        }
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"
#endif
      // The prefix was identified; try to match the rest of the path.
      auto name = path + std::strlen (prefix);
#pragma GCC diagnostic pop
 
      for (auto&& p : registry_list__)
        {
          if (p.match_name (name))
            {
              return static_cast<value_type*> (&p);
            }
        }
 
      // Not a known device.
      return nullptr;
    }
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wexit-time-destructors"
#pragma clang diagnostic ignored "-Wglobal-constructors"
#endif
 
    // Initialised to 0 by BSS.
    template <typename T>
    typename device_registry<T>::device_list
        device_registry<T>::registry_list__;
 
#pragma GCC diagnostic pop
 
    // ========================================================================
  } /* namespace posix */
} /* namespace os */
 
#pragma GCC diagnostic pop
 
// ----------------------------------------------------------------------------
 
#endif /* __cplusplus */
 
// ----------------------------------------------------------------------------
 
#endif /* CMSIS_PLUS_POSIX_IO_DEVICE_REGISTRY_H_ */