Task manager for managing a set of long-running QgsTask tasks. More...

#include <qgstaskmanager.h>

Inheritance diagram for QgsTaskManager:

Classes
struct	TaskDefinition
	Definition of a task for inclusion in the manager. More...

Public Slots
void	triggerTask (QgsTask *task)
	Triggers a task, e.g. More...

Signals
void	allTasksFinished ()
	Emitted when all tasks are complete. More...

void	countActiveTasksChanged (int count)
	Emitted when the number of active tasks changes. More...

void	finalTaskProgressChanged (double progress)
	Will be emitted when only a single task remains to complete and that task has reported a progress change. More...

void	progressChanged (long taskId, double progress)
	Will be emitted when a task reports a progress change. More...

void	statusChanged (long taskId, int status)
	Will be emitted when a task reports a status change. More...

void	taskAboutToBeDeleted (long taskId)
	Emitted when a task is about to be deleted. More...

void	taskAdded (long taskId)
	Emitted when a new task has been added to the manager. More...

void	taskTriggered (QgsTask *task)
	Emitted when a task is triggered. More...

Public Member Functions
	QgsTaskManager (QObject *parent=nullptr)
	Constructor for QgsTaskManager. More...

	~QgsTaskManager () override

QList< QgsTask *>	activeTasks () const
	Returns a list of the active (queued or running) tasks. More...

long	addTask (QgsTask *task, int priority=0)
	Adds a task to the manager. More...

long	addTask (const TaskDefinition &task, int priority=0)
	Adds a task to the manager, using a full task definition (including dependency handling). More...

void	cancelAll ()
	Instructs all tasks tracked by the manager to terminate. More...

int	count () const
	Returns the number of tasks tracked by the manager. More...

int	countActiveTasks () const
	Returns the number of active (queued or running) tasks. More...

QSet< long >	dependencies (long taskId) const
	Returns the set of task IDs on which a task is dependent. More...

bool	dependenciesSatisfied (long taskId) const
	Returns `true` if all dependencies for the specified task are satisfied. More...

QList< QgsMapLayer *>	dependentLayers (long taskId) const
	Returns a list of layers on which as task is dependent. More...

QgsTask *	task (long id) const
	Returns the task with matching ID. More...

long	taskId (QgsTask *task) const
	Returns the unique task ID corresponding to a task managed by the class. More...

QList< QgsTask * >	tasks () const
	Returns all tasks tracked by the manager. More...

QList< QgsTask *>	tasksDependentOnLayer (QgsMapLayer *layer) const
	Returns a list of tasks which depend on a layer. More...

Friends
class	TestQgsTaskManager

Detailed Description

Task manager for managing a set of long-running QgsTask tasks.

This class can be created directly, or accessed via QgsApplication::taskManager().

Since: QGIS 3.0

Definition at line 369 of file qgstaskmanager.h.

Constructor & Destructor Documentation

◆ QgsTaskManager()

QgsTaskManager::QgsTaskManager ( QObject * parent = nullptr )

Constructor for QgsTaskManager.

Parameters

parent parent QObject

Definition at line 370 of file qgstaskmanager.cpp.

◆ ~QgsTaskManager()

QgsTaskManager::~QgsTaskManager ( )

override

Definition at line 378 of file qgstaskmanager.cpp.

Member Function Documentation

◆ activeTasks()

QList< QgsTask * > QgsTaskManager::activeTasks ( ) const

Returns a list of the active (queued or running) tasks.

See also: countActiveTasks()

Definition at line 624 of file qgstaskmanager.cpp.

◆ addTask() [1/2]

long QgsTaskManager::addTask	(	QgsTask *	task,
		int	priority = `0`
	)

Adds a task to the manager.

Ownership of the task is transferred to the manager, and the task manager will be responsible for starting the task. The priority argument can be used to control the run queue's order of execution, with larger numbers taking precedence over lower priority numbers.

Returns: unique task ID, or 0 if task could not be added

Definition at line 397 of file qgstaskmanager.cpp.

◆ addTask() [2/2]

long QgsTaskManager::addTask	(	const TaskDefinition &	task,
		int	priority = `0`
	)

Adds a task to the manager, using a full task definition (including dependency handling).

Ownership of the task is transferred to the manager, and the task manager will be responsible for starting the task. The priority argument can be used to control the run queue's order of execution, with larger numbers taking precedence over lower priority numbers.

Returns: unique task ID, or 0 if task could not be added

Definition at line 402 of file qgstaskmanager.cpp.

◆ allTasksFinished

void QgsTaskManager::allTasksFinished ( )

signal

Emitted when all tasks are complete.

See also: countActiveTasksChanged()

◆ cancelAll()

void QgsTaskManager::cancelAll ( )

Instructs all tasks tracked by the manager to terminate.

Individual tasks may take some time to cancel, or may totally ignore this instruction. Calling this does not block but will instead signal the tasks to cancel and then return immediately.

Definition at line 512 of file qgstaskmanager.cpp.

◆ count()

int QgsTaskManager::count ( ) const

Returns the number of tasks tracked by the manager.

Definition at line 489 of file qgstaskmanager.cpp.

◆ countActiveTasks()

int QgsTaskManager::countActiveTasks ( ) const

Returns the number of active (queued or running) tasks.

See also: activeTasks(); countActiveTasksChanged()

Definition at line 632 of file qgstaskmanager.cpp.

◆ countActiveTasksChanged

void QgsTaskManager::countActiveTasksChanged ( int count )

signal

Emitted when the number of active tasks changes.

See also: countActiveTasks()

◆ dependencies()

QSet< long > QgsTaskManager::dependencies ( long taskId ) const

Returns the set of task IDs on which a task is dependent.

Note: not available in Python bindings

Definition at line 546 of file qgstaskmanager.cpp.

◆ dependenciesSatisfied()

bool QgsTaskManager::dependenciesSatisfied ( long taskId ) const

Returns true if all dependencies for the specified task are satisfied.

Definition at line 526 of file qgstaskmanager.cpp.

◆ dependentLayers()

QList< QgsMapLayer * > QgsTaskManager::dependentLayers ( long taskId ) const

Returns a list of layers on which as task is dependent.

The task will automatically be canceled if any of these layers are about to be removed.

Parameters

taskId task ID

Returns: list of layers

See also: tasksDependentOnLayer()

Definition at line 601 of file qgstaskmanager.cpp.

◆ finalTaskProgressChanged

void QgsTaskManager::finalTaskProgressChanged ( double progress )

signal

Will be emitted when only a single task remains to complete and that task has reported a progress change.

Parameters

progress percent of progress, from 0.0 - 100.0

◆ progressChanged

void QgsTaskManager::progressChanged	(	long	taskId,
		double	progress
	)

signal

Will be emitted when a task reports a progress change.

Parameters

taskId	ID of task
progress	percent of progress, from 0.0 - 100.0

◆ statusChanged

void QgsTaskManager::statusChanged	(	long	taskId,
		int	status
	)

signal

Will be emitted when a task reports a status change.

Parameters

taskId	ID of task
status	new task status

◆ task()

QgsTask * QgsTaskManager::task ( long id ) const

Returns the task with matching ID.

Parameters

id task ID

Returns: task if found, or nullptr

Definition at line 474 of file qgstaskmanager.cpp.

◆ taskAboutToBeDeleted

void QgsTaskManager::taskAboutToBeDeleted ( long taskId )

signal

Emitted when a task is about to be deleted.

Parameters

taskId ID of task

◆ taskAdded

void QgsTaskManager::taskAdded ( long taskId )

signal

Emitted when a new task has been added to the manager.

Parameters

taskId ID of task

◆ taskId()

long QgsTaskManager::taskId ( QgsTask * task ) const

Returns the unique task ID corresponding to a task managed by the class.

Parameters

task	task to find

Returns: task ID, or -1 if task not found

Definition at line 495 of file qgstaskmanager.cpp.

◆ tasks()

QList< QgsTask * > QgsTaskManager::tasks ( ) const

Returns all tasks tracked by the manager.

Definition at line 483 of file qgstaskmanager.cpp.

◆ tasksDependentOnLayer()

QList< QgsTask * > QgsTaskManager::tasksDependentOnLayer ( QgsMapLayer * layer ) const

Returns a list of tasks which depend on a layer.

See also: dependentLayers()

Definition at line 607 of file qgstaskmanager.cpp.

◆ taskTriggered

void QgsTaskManager::taskTriggered ( QgsTask * task )

signal

Emitted when a task is triggered.

This occurs when a user clicks on the task from the QGIS GUI, and can be used to show detailed progress reports or re-open a related dialog.

See also: triggerTask()

◆ triggerTask

void QgsTaskManager::triggerTask ( QgsTask * task )

slot

Triggers a task, e.g.

as a result of a GUI interaction.

See also: taskTriggered()

Definition at line 639 of file qgstaskmanager.cpp.

Friends And Related Function Documentation

◆ TestQgsTaskManager

friend class TestQgsTaskManager

friend

Definition at line 620 of file qgstaskmanager.h.

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

/tmp/buildd/qgis-3.8.0+99unstable/src/core/qgstaskmanager.h
/tmp/buildd/qgis-3.8.0+99unstable/src/core/qgstaskmanager.cpp

Classes

Public Slots

Signals

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ QgsTaskManager()

◆ ~QgsTaskManager()

Member Function Documentation

◆ activeTasks()

◆ addTask() [1/2]

◆ addTask() [2/2]

◆ allTasksFinished

◆ cancelAll()

◆ count()

◆ countActiveTasks()

◆ countActiveTasksChanged

◆ dependencies()

◆ dependenciesSatisfied()

◆ dependentLayers()

◆ finalTaskProgressChanged

◆ progressChanged

◆ statusChanged

◆ task()

◆ taskAboutToBeDeleted

◆ taskAdded

◆ taskId()

◆ tasks()

◆ tasksDependentOnLayer()

◆ taskTriggered

◆ triggerTask

Friends And Related Function Documentation

◆ TestQgsTaskManager