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Section _System (group _Tools) · Namespace utils::system · Headers utils/system/
Tools for the program itself: id distribution, delayed tasks and a pool of workers.
IdHandler<T> (T integer) gives unique ids, starting at 1 (0 is reserved as "no id"), and reuses the freed ones first. Every method takes safe_mode = true (lock, thread safe).
| Method | Description |
|---|---|
allocate() / allocate(T& id)
|
Give a free id (and store it in id) |
free(id) |
Give back an id (DoubleFree, UnknownId for an id never given) |
use(id) |
Force an id as used (DoubleUse when already used) |
preview() |
Next id allocate would give |
id() / actual()
|
Counter / last id given |
clear() / free()
|
Free every id |
Warning
When the type limit is reached, allocate throws FatalException(IdOverflow) (ends the program), preview an ErrorException(IdOverflow).
Runs a function after a delay, each task on its own thread.
| Method | Description |
|---|---|
schedule(delay, fn) |
Run fn() after delay (std::chrono::milliseconds), returns the task id |
cancel(id) |
Cancel one task (UnknownId when finished / unknown) |
cancel() |
Cancel every pending task (also done by the destructor) |
utils::system::Scheduler scheduler;
std::size_t id = scheduler.schedule(std::chrono::milliseconds{500}, [](void) {std::cout << "later" << std::endl;});
scheduler.cancel(id);LoadBalancer<T>(limit = 1, lifespan = 0ms) keeps a pool of workers (T is a utils::type::Worker or derives it, see Type) and gives a free one.
| Method | Description |
|---|---|
spawn(n = 1) |
Add n workers (OutOfBounds over the limit, 0 = no limit) |
getWorker() |
std::future<T&> resolved with a free worker, marked working (waits until one is free) |
kill() / kill(n)
|
Remove the free workers / n workers (the free ones first) |
kill<true>() / kill<true>(n)
|
Same, also removing the working ones |
setLimit(n) / getLimit()
|
Maximum number of workers |
setLifespan(ms) / getLifespan()
|
A worker free for longer is removed (0 = never) |
size() |
Number of workers |
The worker is given back with worker.setWorkingStatus(false). A getWorker still waiting when the balancer is destroyed throws PromiseCanceled from future.get().
utils::system::LoadBalancer<utils::type::Worker> balancer(4, std::chrono::seconds{30});
balancer.spawn(2);
utils::type::Worker& worker = balancer.getWorker().get();
// ... work ...
worker.setWorkingStatus(false);