FvBaseThread Class Reference

FireVision base thread. More...

#include <base_thread.h>

Inheritance diagram for FvBaseThread:

[legend]
List of all members.

Public Member Functions

 FvBaseThread ()
 Constructor.
virtual ~FvBaseThread ()
 Destructor.
virtual void init ()
 Initialize the thread.
virtual void loop ()
 Thread loop.
virtual void finalize ()
 Finalize the thread.
virtual firevision::VisionMastervision_master ()
 Get vision master.
virtual firevision::Cameraregister_for_camera (const char *camera_string, fawkes::Thread *thread, firevision::colorspace_t cspace=firevision::YUV422_PLANAR)
 Register thread for camera.
virtual firevision::Cameraregister_for_raw_camera (const char *camera_string, fawkes::Thread *thread)
 Register thread for camera.
virtual void unregister_thread (fawkes::Thread *thread)
 Unregister a thread.
virtual firevision::CameraControlacquire_camctrl (const char *cam_string)
 Retrieve a CameraControl for the specified camera string.
virtual void release_camctrl (firevision::CameraControl *cc)
 Release a camera control.
virtual bool thread_started (fawkes::Thread *thread) throw ()
 Thread started successfully.
virtual bool thread_init_failed (fawkes::Thread *thread) throw ()
 Thread initialization failed.

Protected Member Functions

virtual void run ()
 Stub to see name in backtrace for easier debugging.
virtual firevision::CameraControlacquire_camctrl (const char *cam_string, const std::type_info &typeinf)
 Retrieve a CameraControl for the specified camera string and type info.

Detailed Description

FireVision base thread.

This implements the functionality of the FvBasePlugin.

Author:
Tim Niemueller

Definition at line 46 of file base_thread.h.


Constructor & Destructor Documentation

FvBaseThread::FvBaseThread (  ) 

Constructor.

Definition at line 56 of file base_thread.cpp.

FvBaseThread::~FvBaseThread (  )  [virtual]

Destructor.

Definition at line 68 of file base_thread.cpp.


Member Function Documentation

CameraControl * FvBaseThread::acquire_camctrl ( const char *  cam_string,
const std::type_info &  typeinf 
) [protected, virtual]

Retrieve a CameraControl for the specified camera string and type info.

This utility method is used by the template methods to instantiate the cameras with a specified intended type.

Parameters:
cam_string Camera argument string, see method description for details
typeinf type info for intended camera control type
Returns:
a pointer to the requested CameraControl.
Exceptions:
Exception no camera was found matching the cam_string and the factory could not instantiate a camera control with the given string.

Implements firevision::VisionMaster.

Definition at line 346 of file base_thread.cpp.

References firevision::CameraArgumentParser::cam_id(), firevision::CameraArgumentParser::cam_type(), and fawkes::LockMap< KeyType, ValueType, LessKey >::mutex().

CameraControl * FvBaseThread::acquire_camctrl ( const char *  cam_string  )  [virtual]

Retrieve a CameraControl for the specified camera string.

This control (if available) can be used to control certain aspects of the Camera. The cam_string argument either is the string that has been used to register for a particular camera, or it is a string denoting a camera control by itself. In the former case the vision master will look if the camera has been registered, and then checks if the camera provides a camera control. If so the control is returned. Note that it might implement multiple different camera controls. If you want a specific camera control use one of the template methods to get a correctly typed and verified control. If no camera that matches the cam_string is found, the vision master will try to instantiate a new camera control using the cam_string as argument to the CameraControlFactory.

Parameters:
cam_string Camera argument string, see method description for details
Returns:
a pointer to the requested CameraControl.
Exceptions:
Exception no camera was found matching the cam_string and the factory could not instantiate a camera control with the given string.

Implements firevision::VisionMaster.

Definition at line 330 of file base_thread.cpp.

References firevision::CameraArgumentParser::cam_id(), firevision::CameraArgumentParser::cam_type(), and fawkes::LockMap< KeyType, ValueType, LessKey >::mutex().

void FvBaseThread::finalize (  )  [virtual]

Finalize the thread.

This method is executed just before the thread is canceled and destroyed. It is always preceeded by a call to prepare_finalize(). If this is not the case this is a failure. The condition can be checked with the boolean variable finalize_prepared.

This method is meant to be used in conjunction with aspects and to cover thread inter-dependencies. This routine MUST bring the thread into a safe state such that it may be canceled and destroyed afterwards. If there is any reason that this cannot happen make your prepare_finalize() reports so.

This method is called by the thread manager just before the thread is being cancelled. Here you can do whatever steps are necessary just before the thread is cancelled. Note that you thread is still running and might be in the middle of a loop, so it is not a good place to give up on all resources used. Mind segmentation faults that could happen. Protect the area with a mutex that you lock at the beginning of your loop and free in the end, and that you lock at the beginning of finalize and then never unlock. Also not that the finalization may be canceled afterwards. The next thing that happens is that either the thread is canceled and destroyed or that the finalization is canceled and the thread has to run again.

Finalize is called on a thread just before it is deleted. It is guaranteed to be called on a fully initialized thread (if no exception is thrown in init()) (this guarantee holds in the Fawkes framework).

The default implementation does nothing besides throwing an exception if prepare_finalize() has not been called.

Exceptions:
Exception thrown if prepare_finalize() has not been called.
See also:
prepare_finalize()

cancel_finalize()

Reimplemented from fawkes::Thread.

Definition at line 85 of file base_thread.cpp.

References fawkes::LockList< Type >::lock(), fawkes::LockMap< KeyType, ValueType, LessKey >::lock(), fawkes::ThreadCollector::remove(), fawkes::ThreadProducerAspect::thread_collector, fawkes::LockList< Type >::unlock(), and fawkes::LockMap< KeyType, ValueType, LessKey >::unlock().

void FvBaseThread::init (  )  [virtual]

Initialize the thread.

This method is meant to be used in conjunction with aspects. Some parts of the initialization may only happen after some aspect of the thread has been initialized. Implement the init method with these actions. It is guaranteed to be called just after all aspects have been initialized and only once in the lifetime of the thread. Throw an exception if any problem occurs and the thread should not run.

Just because your init() routine suceeds and everything looks fine for this thread does not automatically imply that it will run. If it belongs to a group of threads in a ThreadList and any of the other threads fail to initialize then no thread from this group is run and thus this thread will never run. In that situation finalize() is called for this very instance, prepare_finalize() however is not called.

See also:
Fawkes Thread Aspects

Reimplemented from fawkes::Thread.

Definition at line 75 of file base_thread.cpp.

void FvBaseThread::loop (  )  [virtual]

Thread loop.

Reimplemented from fawkes::Thread.

Definition at line 106 of file base_thread.cpp.

References FvAcquisitionThread::AqtContinuous, FvAcquisitionThread::AqtCyclic, fawkes::LockMap< KeyType, ValueType, LessKey >::lock(), fawkes::Logger::log_info(), fawkes::Logger::log_warn(), fawkes::LoggingAspect::logger, fawkes::Thread::name(), fawkes::ThreadCollector::remove(), fawkes::ThreadProducerAspect::thread_collector, fawkes::LockMap< KeyType, ValueType, LessKey >::unlock(), and fawkes::Barrier::wait().

Camera * FvBaseThread::register_for_camera ( const char *  camera_string,
fawkes::Thread thread,
firevision::colorspace_t  cspace = firevision::YUV422_PLANAR 
) [virtual]

Register thread for camera.

This will register a relation between the given thread and the camera identified by the camera string. If the requested camera has not been opened before this is done and the camera is started. If that fails for whatever reason an exception is thrown. In that case the thread is not registered with the vision master. If the camera is available the thread is registered with the vision master. From then on it is woken up whenever new image data is available and it will wait for the thread to finished computation on that very image. It is a critical error that can not be recovered if the thread fails for whatever reason. If there is a critical error condition in the vision thread it must not stop execution but just the computation.

Parameters:
camera_string camera that can be used by CameraFactory to open a camera.
thread thread to register for this camera
cspace the colorspace in which the images should be provided for the camera. Note that using images in different formats at the same time can cause a severe performance penalty. The default is to produce YUV422_PLANAR images, which is used in the FireVision framework as main image format.
Returns:
a pointer to the requested camera. Note that this may not be of the C++ type that you may expect for the requested camera, but it may have layers of indirection. For example when opening a USB camera you could get a shared memory camera to share the camera (image) with multiple threads. Note that using CS_UNKNOWN shall have the similar result as using register_for_raw_camera().

Implements firevision::VisionMaster.

Definition at line 220 of file base_thread.cpp.

References fawkes::ThreadCollector::add(), fawkes::Thread::add_notification_listener(), FvAqtVisionThreads::add_waiting_thread(), fawkes::Exception::append(), firevision::CameraArgumentParser::cam_id(), firevision::CameraArgumentParser::cam_type(), FvAcquisitionThread::camera_instance(), fawkes::ClockAspect::clock, fawkes::LockMap< KeyType, ValueType, LessKey >::lock(), fawkes::Logger::log_info(), fawkes::LoggingAspect::logger, fawkes::Thread::name(), firevision::Camera::open(), firevision::Camera::start(), fawkes::ThreadProducerAspect::thread_collector, fawkes::LockMap< KeyType, ValueType, LessKey >::unlock(), fawkes::VisionAspect::vision_thread_mode(), and FvAcquisitionThread::vision_threads.

Referenced by register_for_raw_camera().

Camera * FvBaseThread::register_for_raw_camera ( const char *  camera_string,
fawkes::Thread thread 
) [virtual]

Register thread for camera.

This will register a relation between the given thread and the camera identified by the camera string similar to register_for_camera(). However, unlike register_for_camera() this method will provide access to the raw camera implementation, without possibly proxies. Once you gathered the camera, you can dynamically cast it to the expected camera type (or use the template method instead. Raw access to a camera is only granted for a single thread. Note that you may not call capture() or dispose() on the camera, this will still be done by the vision master, as the camera may be used by other threads that registered for the camera with register_for_camera().

Parameters:
camera_string camera that can be used by CameraFactory to open a camera.
thread thread to register for this camera
Returns:
raw camera instance, which can by dynamically casted to the expected type.

Implements firevision::VisionMaster.

Definition at line 295 of file base_thread.cpp.

References firevision::CameraArgumentParser::cam_id(), firevision::CameraArgumentParser::cam_type(), firevision::CS_UNKNOWN, fawkes::LockMap< KeyType, ValueType, LessKey >::lock(), register_for_camera(), and fawkes::LockMap< KeyType, ValueType, LessKey >::unlock().

void FvBaseThread::release_camctrl ( firevision::CameraControl cc  )  [virtual]

Release a camera control.

This has to be called when you are done with the camera control. This will release the control and it is no longer valid. The vision master might collect the memory that has been used for the control.

Parameters:
cc camera control instance to release

Implements firevision::VisionMaster.

Definition at line 363 of file base_thread.cpp.

References fawkes::LockList< Type >::lock(), and fawkes::LockList< Type >::unlock().

virtual void FvBaseThread::run (  )  [inline, protected, virtual]

Stub to see name in backtrace for easier debugging.

See also:
Thread::run()

Reimplemented from fawkes::Thread.

Definition at line 82 of file base_thread.h.

bool FvBaseThread::thread_init_failed ( fawkes::Thread thread  )  throw () [virtual]

Thread initialization failed.

This method is called by ThreadList if one of the threads in the list failed to initialize. This is not necessarily the thread that you registered the notification for. However, the argument is always the thread that you registered for, no matter which thread in the list failed.

Parameters:
thread thread that you registered for
Returns:
true to stay registered for further thread notifications, false to unregister.

Implements fawkes::ThreadNotificationListener.

Definition at line 444 of file base_thread.cpp.

bool FvBaseThread::thread_started ( fawkes::Thread thread  )  throw () [virtual]

Thread started successfully.

This is called by the thread itself when the thread started successfully.

Parameters:
thread thread that started successfully
Returns:
true to stay registered for further thread notifications, false to unregister.

Implements fawkes::ThreadNotificationListener.

Definition at line 427 of file base_thread.cpp.

void FvBaseThread::unregister_thread ( fawkes::Thread thread  )  [virtual]

Unregister a thread.

The thread is unregistered and it is removed from the internal structures. The thread is no longer called for new image material that can be processed.

If the unregistered thread was the last thread accessing the camera, it shall be held open for a specified time, such that if the thread is just being restarted the camera does not have to be re-opened. The time to wait is defined by the implementation.

Parameters:
thread thread to unregister

Implements firevision::VisionMaster.

Definition at line 390 of file base_thread.cpp.

References FvAcquisitionThread::AqtContinuous, fawkes::LockMap< KeyType, ValueType, LessKey >::lock(), fawkes::Logger::log_info(), fawkes::LoggingAspect::logger, fawkes::Thread::name(), and fawkes::LockMap< KeyType, ValueType, LessKey >::unlock().

VisionMaster * FvBaseThread::vision_master (  )  [virtual]

Get vision master.

Returns:
vision master

Reimplemented from fawkes::VisionMasterAspect.

Definition at line 213 of file base_thread.cpp.


The documentation for this class was generated from the following files:
Generated on Tue Feb 22 13:32:34 2011 for Fawkes API by  doxygen 1.4.7