Search for usage in LXR

#include <weaver.h>

Inherits ThreadWeaver::QueueAPI.


void threadExited (ThreadWeaver::Thread *)
void threadStarted (ThreadWeaver::Thread *)
void threadSuspended (ThreadWeaver::Thread *)

Public Member Functions

 Weaver (QObject *parent=nullptr)
 ~Weaver () override
int activeThreadCount ()
JobPointer applyForWork (Thread *thread, bool wasBusy) override
void blockThreadUntilJobsAreBeingAssigned (Thread *th)
void blockThreadUntilJobsAreBeingAssigned_locked (Thread *th)
int currentNumberOfThreads () const override
int currentNumberOfThreads_p () const override
void decActiveThreadCount ()
void dequeue () override
bool dequeue (const JobPointer &job) override
void dequeue_p () override
bool dequeue_p (JobPointer job) override
void enqueue (const QVector< JobPointer > &jobs) override
void enqueue_p (const QVector< JobPointer > &jobs)
void finish () override
void finish_p () override
void incActiveThreadCount ()
bool isEmpty () const override
bool isEmpty_p () const override
bool isIdle () const override
bool isIdle_p () const override
int maximumNumberOfThreads () const override
int maximumNumberOfThreads_p () const override
int queueLength () const override
int queueLength_p () const override
void requestAbort () override
void requestAbort_p () override
void reschedule () override
void resume () override
void resume_p () override
void setMaximumNumberOfThreads (int cap) override
void setMaximumNumberOfThreads_p (int cap) override
void setState (StateId)
void setState_p (StateId)
void shutDown () override
void shutDown_p () override
const Statestate () const override
Statestate () override
void suspend () override
void suspend_p () override
JobPointer takeFirstAvailableJobOrSuspendOrWait (Thread *th, bool threadWasBusy, bool suspendIfAllThreadsInactive, bool justReturning)
void threadEnteredRun (Thread *thread)
void waitForAvailableJob (Thread *th) override

Protected Member Functions

void adjustActiveThreadCount (int diff)
void adjustInventory (int noOfNewJobs)
virtual ThreadcreateThread ()

Detailed Description

A Weaver manages worker threads.

It creates an inventory of Thread objects to which it assigns jobs from its queue. It extends the API of Queue, hiding methods that need to be public to implement state handling, but should not be exposed in general.

Definition at line 34 of file weaver.h.

Constructor & Destructor Documentation

◆ Weaver()

Weaver::Weaver ( QObject parent = nullptr)

Constructs a Weaver object.

Definition at line 36 of file weaver.cpp.

◆ ~Weaver()

Weaver::~Weaver ( )

Destructs a Weaver object.

Definition at line 55 of file weaver.cpp.

Member Function Documentation

◆ activeThreadCount()

int Weaver::activeThreadCount ( )

Returns the number of active threads.

Threads are active if they process a job. Requires that the mutex is being held when called.

Definition at line 482 of file weaver.cpp.

◆ adjustActiveThreadCount()

void Weaver::adjustActiveThreadCount ( int  diff)

Adjust active thread count.

This is a helper function for incActiveThreadCount and decActiveThreadCount.

Definition at line 462 of file weaver.cpp.

◆ adjustInventory()

void Weaver::adjustInventory ( int  numberOfNewJobs)

Adjust the inventory size.

Requires that the mutex is being held when called.

This method creates threads on demand. Threads in the inventory are not created upon construction of the WeaverImpl object, but when jobs are queued. This avoids costly delays on the application startup time. Threads are created when the inventory size is under inventoryMin and new jobs are queued.

Definition at line 403 of file weaver.cpp.

◆ applyForWork()

JobPointer Weaver::applyForWork ( Thread th,
bool  wasBusy 

Assign a job to the calling thread.

This is supposed to be called from the Thread objects in the inventory. Do not call this method from your code. Returns 0 if the weaver is shutting down, telling the calling thread to finish and exit. If no jobs are available and shut down is not in progress, the calling thread is suspended until either condition is met.

wasBusyTrue if the thread is returning from processing a job

Definition at line 573 of file weaver.cpp.

◆ blockThreadUntilJobsAreBeingAssigned()

void Weaver::blockThreadUntilJobsAreBeingAssigned ( Thread th)

Blocks the calling thread until jobs can be assigned.

Definition at line 585 of file weaver.cpp.

◆ blockThreadUntilJobsAreBeingAssigned_locked()

void Weaver::blockThreadUntilJobsAreBeingAssigned_locked ( Thread th)

Blocks the calling thread until jobs can be assigned.

The mutex must be held when calling this method.

Definition at line 596 of file weaver.cpp.

◆ createThread()

Thread * Weaver::createThread ( )

Factory method to create the threads.

Overload in adapted Weaver implementations.

Definition at line 438 of file weaver.cpp.

◆ currentNumberOfThreads()

int Weaver::currentNumberOfThreads ( ) const

Returns the current number of threads in the inventory.

Implements ThreadWeaver::QueueInterface.

Definition at line 190 of file weaver.cpp.

◆ decActiveThreadCount()

void Weaver::decActiveThreadCount ( )

brief Decrement the count of active threads.

Definition at line 450 of file weaver.cpp.

◆ dequeue() [1/2]

void Weaver::dequeue ( )

Remove all queued jobs.

All waiting jobs will be dequeued. The semantics are the same as for dequeue(JobInterface).

See also

Implements ThreadWeaver::QueueInterface.

Definition at line 266 of file weaver.cpp.

◆ dequeue() [2/2]

bool Weaver::dequeue ( const JobPointer job)

Remove a job from the queue.

If the job was queued but not started so far, it is removed from the queue.

You can always call dequeue, it will return true if the job was dequeued. However if the job is not in the queue anymore, it is already being executed, it is too late to dequeue, and dequeue will return false. The return value is thread-safe - if true is returned, the job was still waiting, and has been dequeued. If not, the job was not waiting in the queue.

Modifying queued jobs is best done on a suspended queue. Often, for example at the end of an application, it is sufficient to dequeue all jobs (which leaves only the ones mid-air in threads), call finish (that will wait for all the mid air jobs to complete), and then exit. Without dequeue(), all jobs in the queue would be executed during finish().

See also
requestAbort for aborting jobs during execution
true if the job was waiting and has been dequeued
false if the job was not found waiting in the queue

Implements ThreadWeaver::QueueInterface.

Definition at line 238 of file weaver.cpp.

◆ enqueue()

void Weaver::enqueue ( const QVector< JobPointer > &  jobs)

Queue a vector of jobs.

It depends on the state if execution of the job will be attempted immediately. In suspended state, jobs can be added to the queue, but the threads remain suspended. In WorkongHard state, an idle thread may immediately execute the job, or it might be queued if all threads are busy.

JobPointer is a shared pointer. This means the object pointed to will be deleted if this object is the last remaining reference to it. Keep a JobPointer to the job to avoid automatic deletion.

Implements ThreadWeaver::QueueInterface.

Definition at line 203 of file weaver.cpp.

◆ finish()

void Weaver::finish ( )

Finish all queued operations, then return.

This method is used in imperative (not event driven) programs that cannot react on events to have the controlling (main) thread wait wait for the jobs to finish. The call will block the calling thread and return when all queued jobs have been processed.

Warning: This will suspend your thread! Warning: If one of your jobs enters an infinite loop, this will never return!

Implements ThreadWeaver::QueueInterface.

Definition at line 284 of file weaver.cpp.

◆ incActiveThreadCount()

void Weaver::incActiveThreadCount ( )

Increment the count of active threads.

Definition at line 444 of file weaver.cpp.

◆ isEmpty()

bool Weaver::isEmpty ( ) const

Is the queue empty? The queue is empty if no more jobs are queued.

Implements ThreadWeaver::QueueInterface.

Definition at line 334 of file weaver.cpp.

◆ isIdle()

bool Weaver::isIdle ( ) const

Is the weaver idle? The weaver is idle if no jobs are queued and no jobs are processed by the threads.

Implements ThreadWeaver::QueueInterface.

Definition at line 347 of file weaver.cpp.

◆ maximumNumberOfThreads()

int Weaver::maximumNumberOfThreads ( ) const

Get the maximum number of threads this Weaver may start.

Implements ThreadWeaver::QueueInterface.

Definition at line 177 of file weaver.cpp.

◆ queueLength()

int Weaver::queueLength ( ) const

Returns the number of pending jobs.

This will return the number of queued jobs. Jobs that are currently being executed are not part of the queue. All jobs in the queue are waiting to be executed.

Implements ThreadWeaver::QueueInterface.

Definition at line 360 of file weaver.cpp.

◆ requestAbort()

void Weaver::requestAbort ( )

Request aborts of the currently executed jobs.

It is important to understand that aborts are requested, but cannot be guaranteed, as not all Job classes support it. It is up to the application to decide if and how job aborts are necessary.

Implements ThreadWeaver::QueueInterface.

Definition at line 373 of file weaver.cpp.

◆ reschedule()

void Weaver::reschedule ( )

Reschedule the jobs in the queue.

This method triggers a scheduling attempt to perform jobs. It will schedule enqueued jobs to be executed by idle threads. It should only be necessary to call it if the canRun() status of a job changed spontaneously due to external reasons.

Implements ThreadWeaver::QueueInterface.

Definition at line 380 of file weaver.cpp.

◆ resume()

void Weaver::resume ( )

Resume job queueing.

See also

Implements ThreadWeaver::QueueInterface.

Definition at line 322 of file weaver.cpp.

◆ setMaximumNumberOfThreads()

void Weaver::setMaximumNumberOfThreads ( int  cap)

Set the maximum number of threads this Weaver object may start.

Implements ThreadWeaver::QueueInterface.

Definition at line 158 of file weaver.cpp.

◆ setState()

void Weaver::setState ( StateId  id)

Set the Weaver state.

See also

Definition at line 126 of file weaver.cpp.

◆ shutDown()

void Weaver::shutDown ( )

Enter Destructed state.

Once this method returns, it is save to delete this object.

Implements ThreadWeaver::QueueInterface.

Definition at line 64 of file weaver.cpp.

◆ state()

State * Weaver::state ( ) const

Return the state of the weaver object.

Implements ThreadWeaver::QueueInterface.

Definition at line 148 of file weaver.cpp.

◆ suspend()

void Weaver::suspend ( )

Suspend job execution.

When suspending, all threads are allowed to finish the currently assigned job but will not receive a new assignment. When all threads are done processing the assigned job, the signal suspended will() be emitted. If you call suspend() and there are no jobs left to be done, you will immediately receive the suspended() signal.

Implements ThreadWeaver::QueueInterface.

Definition at line 310 of file weaver.cpp.

◆ takeFirstAvailableJobOrSuspendOrWait()

JobPointer Weaver::takeFirstAvailableJobOrSuspendOrWait ( Thread th,
bool  threadWasBusy,
bool  suspendIfInactive,
bool  justReturning 

Take the first available job out of the queue and return it.

The job will be removed from the queue (therefore, take). Only jobs that have no unresolved dependencies are considered available. If only jobs that depend on other unfinished jobs are in the queue, this method blocks on m_jobAvailable.

This method will enter suspended state if the active thread count is now zero and suspendIfAllThreadsInactive is true. If justReturning is true, do not assign a new job, just process the completed previous one.

Definition at line 505 of file weaver.cpp.

◆ threadEnteredRun()

void Weaver::threadEnteredRun ( Thread thread)

Called from a new thread when entering the run method.

Definition at line 489 of file weaver.cpp.

◆ threadExited

void ThreadWeaver::Weaver::threadExited ( ThreadWeaver::Thread )

A thread has exited.

◆ threadStarted

void ThreadWeaver::Weaver::threadStarted ( ThreadWeaver::Thread )

A Thread has been created.

◆ threadSuspended

void ThreadWeaver::Weaver::threadSuspended ( ThreadWeaver::Thread )

A thread has been suspended.

◆ waitForAvailableJob()

void Weaver::waitForAvailableJob ( Thread th)

Wait for a job to become available.

Definition at line 579 of file weaver.cpp.

The documentation for this class was generated from the following files:
This file is part of the KDE documentation.
Documentation copyright © 1996-2022 The KDE developers.
Generated on Sun Dec 4 2022 04:06:48 by doxygen 1.8.17 written by Dimitri van Heesch, © 1997-2006

KDE's Doxygen guidelines are available online.