AsyncTaskManager

class AsyncTaskManager

Bases: TypedReferenceCount, Namable

A class to manage a loose queue of isolated tasks, which can be performed either synchronously (in the foreground thread) or asynchronously (by a background thread).

The AsyncTaskManager is actually a collection of AsyncTaskChains, each of which maintains a list of tasks. Each chain can be either foreground or background (it may run only in the main thread, or it may be serviced by one or more background threads). See AsyncTaskChain for more information.

If you do not require background processing, it is perfectly acceptable to create only one AsyncTaskChain, which runs in the main thread. This is a common configuration.

Inheritance diagram

explicit AsyncTaskManager(std::string const &name)

void add(AsyncTask *task)

Adds the indicated task to the active queue. It is an error if the task is already added to this or any other active queue.

void cleanup(void)

Stops all threads and messily empties the task list. This is intended to be called on destruction only.

AsyncTask *find_task(std::string const &name) const

Returns the first task found with the indicated name, or NULL if there is no task with the indicated name.

If there are multiple tasks with the same name, returns one of them arbitrarily.

AsyncTaskChain *find_task_chain(std::string const &name)

Searches a new AsyncTaskChain of the indicated name and returns it if it exists, or NULL otherwise.

AsyncTaskCollection find_tasks(std::string const &name) const

Returns the list of tasks found with the indicated name.

AsyncTaskCollection find_tasks_matching(GlobPattern const &pattern) const

Returns the list of tasks found whose name matches the indicated glob pattern, e.g. “my_task_*”.

AsyncTaskCollection get_active_tasks(void) const

Returns the set of tasks that are active (and not sleeping) on the task manager, at the time of the call.

static TypeHandle get_class_type(void)

ClockObject *get_clock(void)

Returns the clock pointer used within the AsyncTaskManager. See set_clock().

AsyncTaskManager *get_global_ptr(void)

Returns a pointer to the global AsyncTaskManager. This is the AsyncTaskManager that most code should use for queueing tasks and suchlike.

double get_next_wake_time(void) const

Returns the scheduled time (on the manager’s clock) of the next sleeping task, on any task chain, to awaken. Returns -1 if there are no sleeping tasks.

int get_num_task_chains(void) const

Returns the number of different task chains.

std::size_t get_num_tasks(void) const

Returns the number of tasks that are currently active or sleeping within the task manager.

AsyncTaskCollection get_sleeping_tasks(void) const

Returns the set of tasks that are sleeping (and not active) on the task manager, at the time of the call.

AsyncTaskChain *get_task_chain(int n) const

Returns the nth task chain.

AsyncTaskCollection get_tasks(void) const

Returns the set of tasks that are active or sleeping on the task manager, at the time of the call.

bool has_task(AsyncTask *task) const

Returns true if the indicated task has been added to this AsyncTaskManager, false otherwise.

AsyncTaskChain *make_task_chain(std::string const &name)

Creates a new AsyncTaskChain of the indicated name and stores it within the AsyncTaskManager. If a task chain with this name already exists, returns it instead.

virtual void output(std::ostream &out) const

void poll(void)

Runs through all the tasks in the task list, once, if the task manager is running in single-threaded mode (no threads available). This method does nothing in threaded mode, so it may safely be called in either case.

bool remove(AsyncTask *task)

std::size_t remove(AsyncTaskCollection const &tasks)

Removes the indicated task from the active queue. Returns true if the task is successfully removed, or false if it wasn’t there.

Removes all of the tasks in the AsyncTaskCollection. Returns the number of tasks removed.

bool remove_task_chain(std::string const &name)

Removes the AsyncTaskChain of the indicated name. If the chain still has tasks, this will block until all tasks are finished.

Returns true if successful, or false if the chain did not exist.

void set_clock(ClockObject *clock)

Replaces the clock pointer used within the AsyncTaskManager. This is used to control when tasks with a set_delay() specified will be scheduled. It can also be ticked automatically each epoch, if set_tick_clock() is true.

The default is the global clock pointer.

void start_threads(void)

Starts any requested threads to service the tasks on the queue. This is normally not necessary, since adding a task will start the threads automatically.

void stop_threads(void)

Stops any threads that are currently running. If any tasks are still pending and have not yet been picked up by a thread, they will not be serviced unless poll() or start_threads() is later called.

void wait_for_tasks(void)

Blocks until the task list is empty.

virtual void write(std::ostream &out, int indent_level = 0) const