class scheduler
Defined at line 23 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
Keeps track of runnable and suspended tasks.
This is a low-level building block for implementing executors.
For a concrete implementation, see |fpromise::single_threaded_executor|.
Instances of this object are not thread-safe. Its client is responsible
for providing all necessary synchronization.
Public Methods
void scheduler ()Defined at line 14 of file ../../sdk/lib/fit-promise/scheduler.cc
void ~scheduler ()Defined at line 16 of file ../../sdk/lib/fit-promise/scheduler.cc
void schedule_task (pending_task task)Adds a task to the runnable queue.
Preconditions:
- |task| must be non-empty
Defined at line 18 of file ../../sdk/lib/fit-promise/scheduler.cc
suspended_task::ticket obtain_ticket (ref_count_type initial_refs)Obtains a new ticket with a ref-count of |initial_refs|.
The executor must eventually call |finalize_ticket()| to update the
state of the ticket.
Preconditions:
- |initial_refs| must be at least 1
Defined at line 23 of file ../../sdk/lib/fit-promise/scheduler.cc
void finalize_ticket (suspended_task::ticket ticket, pending_task * task)Updates a ticket after one run of a task's continuation according
to the state of the task after its run. The executor must call this
method after calling |obtain_ticket()| to indicate the disposition of
the task for which the ticket was obtained.
Passing an empty |task| indicates that the task has completed so it
does not need to be resumed.
Passing a non-empty |task| indicates that the task returned a pending
result and may need to be suspended depending on the current state
of the ticket.
- If the ticket has already been resumed, moves |task| into the
runnable queue.
- Otherwise, if the ticket still has a non-zero ref-count, moves |task|
into the suspended task table.
- Otherwise, considers the task abandoned and the caller retains
ownership of |task|.
Preconditions:
- |task| must be non-null (may be empty)
- the ticket must not have already been finalized
Defined at line 29 of file ../../sdk/lib/fit-promise/scheduler.cc
void duplicate_ticket (suspended_task::ticket ticket)Increments the ticket's ref-count.
Preconditions:
- the ticket's ref-count must be non-zero (positive)
Defined at line 52 of file ../../sdk/lib/fit-promise/scheduler.cc
pending_task release_ticket (suspended_task::ticket ticket)Decrements the ticket's ref-count.
If the task's ref-count reaches 0 and has an associated task that
has not already been resumed, returns the associated task back
to the caller.
Otherwise, returns an empty task.
Preconditions:
- the ticket's ref-count must be non-zero (positive)
Defined at line 61 of file ../../sdk/lib/fit-promise/scheduler.cc
bool resume_task_with_ticket (suspended_task::ticket ticket)Resumes a task and decrements the ticket's ref-count.
If the ticket has an associated task that has not already been resumed,
moves its associated task to the runnable queue and returns true.
Otherwise, returns false.
Preconditions:
- the ticket's ref-count must be non-zero (positive)
Defined at line 79 of file ../../sdk/lib/fit-promise/scheduler.cc
void take_runnable_tasks (task_queue * tasks)Takes all tasks in the runnable queue.
Preconditions:
- |tasks| must be non-null and empty
Defined at line 101 of file ../../sdk/lib/fit-promise/scheduler.cc
void take_all_tasks (task_queue * tasks)Takes all remaining tasks, regardless of whether they are runnable
or suspended.
This operation is useful when shutting down an executor.
Preconditions:
- |tasks| must be non-null and empty
Defined at line 106 of file ../../sdk/lib/fit-promise/scheduler.cc
bool has_runnable_tasks ()Returns true if there are any runnable tasks.
Defined at line 111 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
bool has_suspended_tasks ()Returns true if there are any suspended tasks that have yet to
be resumed.
Defined at line 115 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
bool has_outstanding_tickets ()Returns true if there are any tickets that have yet to be finalized,
released, or resumed.
Defined at line 119 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
void scheduler (const scheduler & )Defined at line 121 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
void scheduler (scheduler && )Defined at line 122 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
scheduler & operator= (const scheduler & )Defined at line 123 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h
scheduler & operator= (scheduler && )Defined at line 124 of file ../../sdk/lib/fit-promise/include/lib/fpromise/scheduler.h