[RFC,1/1] Contributing a compound object to the libpthread -- diff

  misc/mutexgear.c | 798 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 misc/mutexgear.h | 667 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 1465 insertions(+)

+ *   // Assign own completion wheel pointer to the item to indicate
the item is being processed.
+ *   // If the pointer value was already not null, it is an indication that
+ *   // the work item is being canceled and no processing is necessary for it.
+ *   if (AtomicSwapPointer(&item->m_worker_wheel_ptr,
&context->m_item_completion_wheel) == NULL)
+ *   {
+ *    // Handle the work item extracted. The item pointer is to remain valid.
+ *    HandleWorkItem(item, &exit_requested); // This is to mark the
work item completed, if necessary
+ *
+ *    // Break the item item-object relation. Failure to do it is
again an indication
+ *    // that the item is being canceled and is going to be deleted
by the canceling thread.
+ *    int unlinked = UnlinkItemFromRelatedObjectList(item);
+ *
+ *    // Roll the wheel to let the other party know that the item
processing is completed.
+ *    pthread_wheel_slaveroll(&context->m_item_completion_wheel);
+ *
+ *    // If this thread was to break the item-object relation...
+ *    if (unlinked)
+ *    {
+ *     // ... it is responsible for deleting the item.
+ *     DeleteWorkItem(item);
+ *    }
+ *   }
+ *  }
+ *
+ *  // Finally detach the wheel on exit
+ *  pthread_wheel_detachslave(&context->m_item_completion_wheel);
+ * }
+ *
+ *
+ * static
+ * void ClientThread_CancelWorkItemsByRelation(pool_context_t *pool,
related_object_t *relation)
+ * {
+ *  work_item_t *item;
+ *  // Iterate removing the relation items one by one...
+ *  while (UnlinkRelatedObjectNextWorkItem(relation, &item))
+ *  {
+ *   // If removing the item from the pool work queue succeeds it means
+ *   // that the work on the item has not been started yet and it can
be safely deleted.
+ *   if (!RemoveItemFromPoolWorkQueue(pool, item))
+ *   {
+ *    // Otherwise, swap a not-NULL value (e.g. the item pointer
itself) with the wheel pointer content.
+ *    // This is to indicate to any workers that the item is being
canceled and does not need to be handled
+ *    // and, at the same time, this is to extract the item
completion wheel pointer
+ *    // that might have been already assigned by a worker there.
+ *    pthread_wheel_t *assigned_completion_wheel = (pthread_wheel_t
*)AtomicSwapPointer(&item->m_worker_wheel_ptr, item);
+ *
+ *    // If the current thread was the first to assign the value, it
is safe to proceed with deletion immediately
+ *    if (assigned_completion_wheel != NULL
+ *     // Otherwise it may be necessary to wait until the item's
handling is over.
+ *     && !IsWorkItemMarkedCompleted(item))
+ *    {
+ *     // Grip on the assigned wheel
+ *     pthread_wheel_gripon(assigned_completion_wheel);
+ *
+ *     // Retry item completion tests...
+ *     while (!IsWorkItemMarkedCompleted(item))
+ *     {
+ *      // ... and turn the wheel until the handling is over
+ *      pthread_wheel_turn(assigned_completion_wheel);
+ *     }
+ *
+ *     // Finally release the wheel
+ *     pthread_wheel_release(assigned_completion_wheel);
+ *    }
+ *   }
+ *
+ *   // Release resources allocated to the item
+ *   DeleteWorkItem(item);
+ *  }
+ * }
+ *
+ * \endcode
+ */
+
+
+#endif // #ifndef __MUTEXWHEEL_H_INCLUDED
+
+/************************************************************************/
+/* The synchronization technique used in this file along with           */
+/* the object implementations is a subject of U.S. Patent application   */
+/* (Application No. 15/155031; Publication No. 2017-0329652)            */
+/************************************************************************/

[RFC,1/1] Contributing a compound object to the libpthread -- diff

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Patch