A simple ACE task that manages a queue of request. More...

#include <QueueTaskBase_T.h>

Inheritance diagram for OpenDDS::DCPS::QueueTaskBase< T >:

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Collaboration diagram for OpenDDS::DCPS::QueueTaskBase< T >:

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Public Member Functions
	QueueTaskBase ()

virtual	~QueueTaskBase ()

int	add (const T &req)

virtual int	open (void *=0)
	Activate the worker threads. More...

virtual int	svc ()
	The "mainline" executed by the worker thread. More...

virtual int	close (u_long flag=0)
	Called when the thread exits. More...

bool	is_shutdown_initiated () const

virtual void	execute (T &req)=0

Public Member Functions inherited from ACE_Task_Base
	ACE_Task_Base (ACE_Thread_Manager *=0)

virtual	~ACE_Task_Base (void)

virtual int	module_closed (void)

virtual int	put (ACE_Message_Block , ACE_Time_Value =0)

virtual int	activate (long flags=THR_NEW_LWP\|THR_JOINABLE\|THR_INHERIT_SCHED, int n_threads=1, int force_active=0, long priority=ACE_DEFAULT_THREAD_PRIORITY, int grp_id=-1, ACE_Task_Base task=0, ACE_hthread_t thread_handles[]=0, void stack[]=0, size_t stack_size[]=0, ACE_thread_t thread_ids[]=0, const char *thr_name[]=0)

virtual int	wait (void)

virtual int	suspend (void)

virtual int	resume (void)

int	grp_id (void) const

void	grp_id (int)

ACE_Thread_Manager *	thr_mgr (void) const

void	thr_mgr (ACE_Thread_Manager *)

int	is_reader (void) const

int	is_writer (void) const

size_t	thr_count (void) const

ACE_thread_t	last_thread (void) const

Public Member Functions inherited from ACE_Service_Object
	ACE_Service_Object (ACE_Reactor *=0)

virtual	~ACE_Service_Object (void)

Public Member Functions inherited from ACE_Event_Handler
virtual	~ACE_Event_Handler (void)

virtual ACE_HANDLE	get_handle (void) const

virtual void	set_handle (ACE_HANDLE)

virtual int	priority (void) const

virtual void	priority (int priority)

virtual int	handle_input (ACE_HANDLE fd=ACE_INVALID_HANDLE)

virtual int	handle_output (ACE_HANDLE fd=ACE_INVALID_HANDLE)

virtual int	handle_exception (ACE_HANDLE fd=ACE_INVALID_HANDLE)

virtual int	handle_timeout (const ACE_Time_Value &current_time, const void *act=0)

virtual int	handle_exit (ACE_Process *)

virtual int	handle_close (ACE_HANDLE handle, ACE_Reactor_Mask close_mask)

virtual int	handle_signal (int signum, siginfo_t =0, ucontext_t =0)

virtual int	resume_handler (void)

virtual int	handle_qos (ACE_HANDLE=ACE_INVALID_HANDLE)

virtual int	handle_group_qos (ACE_HANDLE=ACE_INVALID_HANDLE)

virtual void	reactor (ACE_Reactor *reactor)

virtual ACE_Reactor *	reactor (void) const

virtual ACE_Reactor_Timer_Interface *	reactor_timer_interface (void) const

virtual Reference_Count	add_reference (void)

virtual Reference_Count	remove_reference (void)

Reference_Counting_Policy &	reference_counting_policy (void)

Public Member Functions inherited from ACE_Shared_Object
	ACE_Shared_Object (void)

virtual	~ACE_Shared_Object (void)

virtual int	init (int argc, ACE_TCHAR *argv[])

virtual int	fini (void)

virtual int	info (ACE_TCHAR **info_string, size_t length=0) const

Private Types
typedef ACE_SYNCH_MUTEX	LockType

typedef ACE_Guard< LockType >	GuardType

typedef ConditionVariable< LockType >	ConditionVariableType

typedef ACE_Unbounded_Queue< T >	Queue

Private Attributes
LockType	lock_
	Lock to protect the "state" (all of the data members) of this object. More...

Queue	queue_
	The request queue. More...

ConditionVariableType	work_available_

bool	shutdown_initiated_
	Flag used to initiate a shutdown request to all worker threads. More...

bool	opened_
	Flag used to avoid multiple open() calls. More...

ACE_thread_t	thr_id_
	The id of the thread created by this task. More...

Additional Inherited Members
Public Types inherited from ACE_Event_Handler
typedef long	Reference_Count

Static Public Member Functions inherited from ACE_Task_Base
static ACE_THR_FUNC_RETURN	svc_run (void *)

static void	cleanup (void object, void params)

Static Public Member Functions inherited from ACE_Event_Handler
static ACE_THR_FUNC_RETURN	read_adapter (void *event_handler)

static int	register_stdin_handler (ACE_Event_Handler eh, ACE_Reactor reactor, ACE_Thread_Manager *thr_mgr, int flags=THR_DETACHED)

static int	remove_stdin_handler (ACE_Reactor reactor, ACE_Thread_Manager thr_mgr)

Public Attributes inherited from ACE_Service_Object
	ACE_ALLOC_HOOK_DECLARE

Public Attributes inherited from ACE_Event_Handler
	LO_PRIORITY

	HI_PRIORITY

	NULL_MASK

	READ_MASK

	WRITE_MASK

	EXCEPT_MASK

	ACCEPT_MASK

	CONNECT_MASK

	TIMER_MASK

	QOS_MASK

	GROUP_QOS_MASK

	SIGNAL_MASK

	ALL_EVENTS_MASK

	RWE_MASK

	DONT_CALL

	ACE_EVENT_HANDLER_NOT_RESUMED

	ACE_REACTOR_RESUMES_HANDLER

	ACE_APPLICATION_RESUMES_HANDLER

Protected Types inherited from ACE_Event_Handler
typedef ACE_Atomic_Op< ACE_SYNCH_MUTEX, Reference_Count >	Atomic_Reference_Count

Protected Member Functions inherited from ACE_Event_Handler
	ACE_Event_Handler (ACE_Reactor *=0, int priority=ACE_Event_Handler::LO_PRIORITY)

Protected Attributes inherited from ACE_Task_Base
size_t	thr_count_

ACE_Thread_Manager *	thr_mgr_

u_long	flags_

int	grp_id_

ACE_thread_t	last_thread_id_

Protected Attributes inherited from ACE_Event_Handler
Atomic_Reference_Count	reference_count_

Detailed Description

template<typename T>
class OpenDDS::DCPS::QueueTaskBase< T >

A simple ACE task that manages a queue of request.

Definition at line 40 of file QueueTaskBase_T.h.

Member Typedef Documentation

◆ ConditionVariableType

template<typename T>

typedef ConditionVariable<LockType> OpenDDS::DCPS::QueueTaskBase< T >::ConditionVariableType

private

Definition at line 205 of file QueueTaskBase_T.h.

◆ GuardType

template<typename T>

typedef ACE_Guard<LockType> OpenDDS::DCPS::QueueTaskBase< T >::GuardType

private

Definition at line 204 of file QueueTaskBase_T.h.

◆ LockType

template<typename T>

typedef ACE_SYNCH_MUTEX OpenDDS::DCPS::QueueTaskBase< T >::LockType

private

Definition at line 203 of file QueueTaskBase_T.h.

◆ Queue

template<typename T>

typedef ACE_Unbounded_Queue<T> OpenDDS::DCPS::QueueTaskBase< T >::Queue

private

Definition at line 207 of file QueueTaskBase_T.h.

Constructor & Destructor Documentation

◆ QueueTaskBase()

template<typename T>

OpenDDS::DCPS::QueueTaskBase< T >::QueueTaskBase ( )

inline

Definition at line 42 of file QueueTaskBase_T.h.

   : work_available_(lock_)
   , shutdown_initiated_(false)
   , opened_(false)
   , thr_id_(ACE_OS::NULL_thread)
   {
     DBG_ENTRY("QueueTaskBase","QueueTaskBase");
   }

◆ ~QueueTaskBase()

template<typename T>

virtual OpenDDS::DCPS::QueueTaskBase< T >::~QueueTaskBase ( )

inlinevirtual

Definition at line 51 of file QueueTaskBase_T.h.

                            {
     DBG_ENTRY("QueueTaskBase","~QueueTaskBase");
   }

Member Function Documentation

◆ add()

template<typename T>

int OpenDDS::DCPS::QueueTaskBase< T >::add ( const T & req )

inline

Put the request to the request queue. Returns 0 if successful, -1 otherwise (it has been "rejected" or this task is shutdown).

Definition at line 58 of file QueueTaskBase_T.h.

                         {
     DBG_ENTRY("QueueTaskBase","add");
     GuardType guard(this->lock_);
 
     if (this->shutdown_initiated_)
       return -1;
 
     int result = this->queue_.enqueue_tail(req);
 
     if (result == 0) {
       work_available_.notify_one();
 
     } else
       ACE_ERROR((LM_ERROR, "(%P|%t) ERROR: QueueTaskBase::add %p\n",
        ACE_TEXT("enqueue_tail")));
 
     return result;
   }

◆ close()

template<typename T>

virtual int OpenDDS::DCPS::QueueTaskBase< T >::close ( u_long flag = 0 )

inlinevirtual

Called when the thread exits.

Reimplemented from ACE_Task_Base.

Definition at line 166 of file QueueTaskBase_T.h.

                                      {
     DBG_ENTRY("QueueTaskBase","close");
 
     if (flag == 0)
       return 0;
 
     {
       GuardType guard(this->lock_);
 
       if (this->shutdown_initiated_)
         return 0;
 
       // Set the shutdown flag to true.
       this->shutdown_initiated_ = true;
       work_available_.notify_one();
     }
 
     if (this->opened_ && !ACE_OS::thr_equal(this->thr_id_, ACE_OS::thr_self())) {
       ThreadStatusManager& thread_status_manager = TheServiceParticipant->get_thread_status_manager();
       ThreadStatusManager::Sleeper sleeper(thread_status_manager);
       this->wait();
     }
 
     return 0;
   }

◆ execute()

template<typename T>

virtual void OpenDDS::DCPS::QueueTaskBase< T >::execute ( T & req )

pure virtual

The subclass should implement this function to handle the dequeued request.

Implemented in OpenDDS::DCPS::DataLinkCleanupTask.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::is_shutdown_initiated(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

◆ is_shutdown_initiated()

template<typename T>

bool OpenDDS::DCPS::QueueTaskBase< T >::is_shutdown_initiated ( ) const

inline

Definition at line 192 of file QueueTaskBase_T.h.

                                      {
     GuardType guard(lock_);
     return shutdown_initiated_;
   }

◆ open()

template<typename T>

virtual int OpenDDS::DCPS::QueueTaskBase< T >::open ( void * = 0 )

inlinevirtual

Activate the worker threads.

Reimplemented from ACE_Task_Base.

Definition at line 78 of file QueueTaskBase_T.h.

                               {
     DBG_ENTRY("QueueTaskBase","open");
 
     GuardType guard(this->lock_);
 
     // We can assume that we are in the proper state to handle this open()
     // call as long as we haven't been open()'ed before.
     if (this->opened_) {
       ACE_ERROR_RETURN((LM_ERROR,
                         "(%P|%t) QueueTaskBase failed to open.  "
                         "Task has previously been open()'ed.\n"),
                        -1);
     }
 
     // Activate this task object with one worker thread.
     if (this->activate(THR_NEW_LWP | THR_JOINABLE, 1) != 0) {
       // Assumes that when activate returns non-zero return code that
       // no threads were activated.
       ACE_ERROR_RETURN((LM_ERROR,
                         "(%P|%t) QueueTaskBase failed to activate "
                         "the worker threads.\n"),
                        -1);
     }
 
     // Now we have past the point where we can say we've been open()'ed before.
     this->opened_ = true;
 
     return 0;
   }

◆ svc()

template<typename T>

virtual int OpenDDS::DCPS::QueueTaskBase< T >::svc ( void )

inlinevirtual

The "mainline" executed by the worker thread.

Reimplemented from ACE_Task_Base.

Definition at line 109 of file QueueTaskBase_T.h.

                     {
     DBG_ENTRY("QueueTaskBase","svc");
 
     ThreadStatusManager& thread_status_manager = TheServiceParticipant->get_thread_status_manager();
     const TimeDuration thread_status_interval = thread_status_manager.thread_status_interval();
 
     ThreadStatusManager::Start s(thread_status_manager, "QueueTaskBase");
 
     thr_id_ = ACE_OS::thr_self();
 
     // Start the "GetWork-And-PerformWork" loop for the current worker thread.
     while (!this->shutdown_initiated_) {
       T req;
       {
         GuardType guard(this->lock_);
 
         if (this->queue_.is_empty() && !shutdown_initiated_) {
           if (thread_status_manager.update_thread_status()) {
             MonotonicTimePoint expire = MonotonicTimePoint::now() + thread_status_interval;
 
             do {
               work_available_.wait_until(expire, thread_status_manager);
 
               MonotonicTimePoint now = MonotonicTimePoint::now();
               if (now > expire) {
                 expire = now + thread_status_interval;
               }
             } while (this->queue_.is_empty() && !shutdown_initiated_);
           } else {
             this->work_available_.wait(thread_status_manager);
           }
         }
 
         if (this->shutdown_initiated_)
           break;
 
         int result = queue_.dequeue_head(req);
 
         if (result != 0) {
           //I'm not sure why this thread got more signals than actual signals
           //when using thread_per_connection and the user application thread
           //send requests without interval. We just need ignore the dequeue
           //failure.
           //ACE_ERROR ((LM_ERROR, "(%P|%t) ERROR: QueueTaskBase::svc  %p\n",
           //  ACE_TEXT("dequeue_head")));
           continue;
         }
       }
 
       this->execute(req);
     }
 
     // This will never get executed.
     return 0;
   }

Member Data Documentation

◆ lock_

template<typename T>

LockType OpenDDS::DCPS::QueueTaskBase< T >::lock_

mutableprivate

Lock to protect the "state" (all of the data members) of this object.

Definition at line 210 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::add(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::close(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::is_shutdown_initiated(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::open(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

◆ opened_

template<typename T>

bool OpenDDS::DCPS::QueueTaskBase< T >::opened_

private

Flag used to avoid multiple open() calls.

Definition at line 225 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::close(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::open().

◆ queue_

template<typename T>

Queue OpenDDS::DCPS::QueueTaskBase< T >::queue_

private

The request queue.

Definition at line 213 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::add(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

◆ shutdown_initiated_

template<typename T>

bool OpenDDS::DCPS::QueueTaskBase< T >::shutdown_initiated_

private

Flag used to initiate a shutdown request to all worker threads.

Definition at line 222 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::add(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::close(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::is_shutdown_initiated(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

◆ thr_id_

template<typename T>

ACE_thread_t OpenDDS::DCPS::QueueTaskBase< T >::thr_id_

private

The id of the thread created by this task.

Definition at line 228 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::close(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

◆ work_available_

template<typename T>

ConditionVariableType OpenDDS::DCPS::QueueTaskBase< T >::work_available_

private

Condition used to signal the worker threads that they may be able to find a request in the queue_ that needs to be executed. This condition will be signal()'ed each time a request is added to the queue_, and also when this task is shutdown.

Definition at line 219 of file QueueTaskBase_T.h.

Referenced by OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::add(), OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::close(), and OpenDDS::DCPS::QueueTaskBase< DataLink_rch >::svc().

The documentation for this class was generated from the following file:

QueueTaskBase_T.h

Public Member Functions

Private Types

Private Attributes

Additional Inherited Members

Detailed Description

template<typename T> class OpenDDS::DCPS::QueueTaskBase< T >

Member Typedef Documentation

◆ ConditionVariableType

◆ GuardType

◆ LockType

◆ Queue

Constructor & Destructor Documentation

◆ QueueTaskBase()

◆ ~QueueTaskBase()

Member Function Documentation

◆ add()

◆ close()

◆ execute()

◆ is_shutdown_initiated()

◆ open()

◆ svc()

Member Data Documentation

◆ lock_

◆ opened_

◆ queue_

◆ shutdown_initiated_

◆ thr_id_

◆ work_available_

template<typename T>
class OpenDDS::DCPS::QueueTaskBase< T >