os-lists.cpp

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2016-2025 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.
 */
 
#if defined(OS_USE_OS_APP_CONFIG_H)
#include <cmsis-plus/os-app-config.h>
#endif
 
#include <cmsis-plus/rtos/os.h>
 
#include <cmsis-plus/diag/trace.h>
 
// ----------------------------------------------------------------------------
 
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#endif
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace rtos
  {
    namespace internal
    {
      // ======================================================================
 
      void
      thread_children_list::link (thread& thread)
      {
        // Add thread intrusive node at the end of the list.
        insert_after (thread.child_links_,
                      const_cast<utils::static_double_list_links*> (tail ()));
      }
 
      // ======================================================================
 
      void
      ready_threads_list::link (waiting_thread_node& node)
      {
        if (head_.prev () == nullptr)
          {
            // If this is the first time, initialise the list to empty.
            clear ();
          }
 
        thread::priority_t prio = node.thread_->priority ();
 
        waiting_thread_node* after = static_cast<waiting_thread_node*> (
            const_cast<utils::static_double_list_links*> (tail ()));
 
        if (empty ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() empty +%u\n", __func__, prio);
#endif
          }
        else if (prio <= after->thread_->priority ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() back %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
        else if (prio > head ()->thread_->priority ())
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert at the beginning of the list.
            after = static_cast<waiting_thread_node*> (
                const_cast<utils::static_double_list_links*> (&head_));
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() front +%u %u \n", __func__, prio,
                           head ()->thread_->priority ());
#endif
          }
        else
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert in the middle of the list.
            // The loop is guaranteed to terminate, and not hit the head.
            // The weight is relatively small, priority() is not heavy.
            while (prio > after->thread_->priority ())
              {
                after = static_cast<waiting_thread_node*> (
                    const_cast<utils::static_double_list_links*> (
                        after->prev ()));
              }
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("ready %s() middle %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
 
        insert_after (node, after);
 
        node.thread_->state_ = thread::state::ready;
      }
 
      thread*
      ready_threads_list::unlink_head (void)
      {
        assert (!empty ());
 
        thread* th = head ()->thread_;
 
#if defined(OS_TRACE_RTOS_LISTS)
        trace::printf ("ready %s() %p %s\n", __func__, th, th->name ());
#endif
 
        const_cast<waiting_thread_node*> (head ())->unlink ();
 
        assert (th != nullptr);
 
        // Unlinking is immediately followed by a context switch,
        // so in order to guarantee that the thread is marked as
        // running, it is saver to do it here.
 
        th->state_ = thread::state::running;
        return th;
      }
 
      // ======================================================================
 
      void
      waiting_threads_list::link (waiting_thread_node& node)
      {
        thread::priority_t prio = node.thread_->priority ();
 
        waiting_thread_node* after = static_cast<waiting_thread_node*> (
            const_cast<utils::static_double_list_links*> (tail ()));
 
        if (empty ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("wait %s() empty +%u\n", __func__, prio);
#endif
          }
        else if (prio <= after->thread_->priority ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("wait %s() back %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
        else if (prio > head ()->thread_->priority ())
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert at the beginning of the list.
            after = static_cast<waiting_thread_node*> (
                const_cast<utils::static_double_list_links*> (&head_));
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("wait %s() front +%u %u \n", __func__, prio,
                           head ()->thread_->priority ());
#endif
          }
        else
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert in the middle of the list.
            // The loop is guaranteed to terminate, and not hit the head.
            // The weight is relatively small, priority() is not heavy.
            while (prio > after->thread_->priority ())
              {
                after = static_cast<waiting_thread_node*> (
                    const_cast<utils::static_double_list_links*> (
                        after->prev ()));
              }
#pragma GCC diagnostic pop
 
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("wait %s() middle %u +%u \n", __func__,
                           after->thread_->priority (), prio);
#endif
          }
 
        insert_after (node, after);
      }
 
      bool
      waiting_threads_list::resume_one (void)
      {
        thread* th;
        {
          // ----- Enter critical section -------------------------------------
          interrupts::critical_section ics;
 
          // If the list is empty, silently return.
          if (empty ())
            {
              return false;
            }
 
          // The top priority is to remove the entry from the list
          // so that subsequent wakeups to address different threads.
          th = head ()->thread_;
          const_cast<waiting_thread_node*> (head ())->unlink ();
          // ----- Exit critical section --------------------------------------
        }
        assert (th != nullptr);
 
        thread::state_t state = th->state ();
        if (state != thread::state::destroyed)
          {
            th->resume ();
          }
        else
          {
#if defined(OS_TRACE_RTOS_LISTS)
            trace::printf ("%s() gone \n", __func__);
#endif
          }
 
        return true;
      }
 
      void
      waiting_threads_list::resume_all (void)
      {
        while (resume_one ())
          ;
      }
 
      // ======================================================================
 
      timestamp_node::timestamp_node (clock::timestamp_t ts) : timestamp (ts)
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      timestamp_node::~timestamp_node ()
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      // ======================================================================
 
      timeout_thread_node::timeout_thread_node (clock::timestamp_t ts,
                                                rtos::thread& th)
          : timestamp_node{ ts }, //
            thread (th)
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      timeout_thread_node::~timeout_thread_node ()
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      // Must be called in a critical section.
      void
      timeout_thread_node::action (void)
      {
        rtos::thread* th = &this->thread;
        this->unlink ();
 
        thread::state_t state = th->state ();
        if (state != thread::state::destroyed)
          {
            th->resume ();
          }
      }
 
      // ======================================================================
 
#if !defined(OS_USE_RTOS_PORT_TIMER)
 
      timer_node::timer_node (clock::timestamp_t ts, timer& tm)
          : timestamp_node{ ts }, //
            tmr (tm)
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      timer_node::~timer_node ()
      {
#if defined(OS_TRACE_RTOS_LISTS_CONSTRUCT)
        trace::printf ("%s() %p \n", __func__, this);
#endif
      }
 
      void
      timer_node::action (void)
      {
        this->unlink ();
        tmr.internal_interrupt_service_routine ();
      }
 
#endif
 
      // ======================================================================
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wnull-dereference"
#endif
      void
      clock_timestamps_list::link (timestamp_node& node)
      {
        clock::timestamp_t timestamp = node.timestamp;
 
        timeout_thread_node* after = static_cast<timeout_thread_node*> (
            const_cast<utils::static_double_list_links*> (tail ()));
 
        if (empty ())
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS_CLOCKS)
            trace::printf ("clock %s() empty +%u\n", __func__,
                           static_cast<uint32_t> (timestamp));
#endif
          }
        else if (timestamp >= after->timestamp)
          {
            // Insert at the end of the list.
#if defined(OS_TRACE_RTOS_LISTS_CLOCKS)
            trace::printf ("clock %s() back %u +%u\n", __func__,
                           static_cast<uint32_t> (after->timestamp),
                           static_cast<uint32_t> (timestamp));
#endif
          }
        else if (timestamp < head ()->timestamp)
          {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
            // Insert at the beginning of the list
            // and update the new head.
            after = static_cast<timeout_thread_node*> (
                const_cast<utils::static_double_list_links*> (&head_));
#if defined(OS_TRACE_RTOS_LISTS_CLOCKS)
            trace::printf ("clock %s() front +%u %u\n", __func__,
                           static_cast<uint32_t> (timestamp),
                           static_cast<uint32_t> (head ()->timestamp));
#endif
#pragma GCC diagnostic pop
          }
        else
          {
            // Insert in the middle of the list.
            // The loop is guaranteed to terminate.
            while (timestamp < after->timestamp)
              {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
                after = static_cast<timeout_thread_node*> (
                    const_cast<utils::static_double_list_links*> (
                        after->prev ()));
              }
#if defined(OS_TRACE_RTOS_LISTS_CLOCKS)
            trace::printf ("clock %s() middle %u +%u\n", __func__,
                           static_cast<uint32_t> (after->timestamp),
                           static_cast<uint32_t> (timestamp));
#endif
#pragma GCC diagnostic pop
          }
 
        insert_after (node, after);
      }
#pragma GCC diagnostic pop
 
      void
      clock_timestamps_list::check_timestamp (clock::timestamp_t now)
      {
        if (head_.next () == nullptr)
          {
            // This happens before the constructors are executed.
            return;
          }
 
        // Multiple threads can wait for the same time stamp, so
        // iterate until a node with future time stamp is identified.
        for (;;)
          {
            // ----- Enter critical section -----------------------------------
            interrupts::critical_section ics;
 
            if (empty ())
              {
                break;
              }
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wnull-dereference"
#endif
            clock::timestamp_t head_ts = head ()->timestamp;
#pragma GCC diagnostic pop
            if (now >= head_ts)
              {
#if defined(OS_TRACE_RTOS_LISTS_CLOCKS)
                trace::printf ("%s() %u \n", __func__,
                               static_cast<uint32_t> (sysclock.now ()));
#endif
                const_cast<timestamp_node*> (head ())->action ();
              }
            else
              {
                break;
              }
            // ----- Exit critical section ------------------------------------
          }
      }
 
      // ======================================================================
 
      void
      terminated_threads_list::link (waiting_thread_node& node)
      {
        if (head_.prev () == nullptr)
          {
            // If this is the first time, initialise the list to empty.
            clear ();
          }
 
        waiting_thread_node* after = static_cast<waiting_thread_node*> (
            const_cast<utils::static_double_list_links*> (tail ()));
 
#if defined(OS_TRACE_RTOS_THREAD)
        trace::printf ("terminated %s() %p %s\n", __func__, &node.thread_,
                       node.thread_->name ());
#endif
 
        node.thread_->state_ = thread::state::terminated;
 
        insert_after (node, after);
      }
 
      // ----------------------------------------------------------------------
    } /* namespace internal */
  } /* namespace rtos */
} /* namespace os */
 
// ----------------------------------------------------------------------------