Future.cpp

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#include <Ark/VM/Future.hpp>
 
#include <Ark/VM/VM.hpp>
#include <Ark/VM/DefaultValues.hpp>
 
namespace Ark::internal
{
    UserType::ControlFuncs Future::ControlFunctions = {
        .ostream_func = [](std::ostream& os, const UserType& user) -> std::ostream& {
            os << "Future@" << user.data();
            return os;
        },
        .deleter = [](void* data) {
            Future* f = static_cast<Future*>(data);
            f->deleteSelfViaVM();
        }
    };
 
    // cppcheck-suppress constParameterReference
    Future::Future(ExecutionContext* context, VM* vm, std::vector<Value>& args) :
        m_vm(vm)
    {
        m_value = std::async(
            std::launch::async,
            [vm, context, args]() mutable {
                const Value res = vm->resolve(context, args);
                // We need to mark the context as free to use as soon as possible,
                // because if we do it in `Future::resolve`, it will never be marked as free
                // if the future is not awaited, even though it can already be reused.
                // The value is returned as a copy by VM::resolve, and not a reference,
                // thus it is okay to get rid of the context.
                vm->deleteContext(context);
                return res;
            });
    }
 
    Value Future::resolve()
    {
        if (!m_value.valid())
            return Nil;
 
        m_value.wait();
        Value res = m_value.get();
        return res;
    }
 
    void Future::deleteSelfViaVM()
    {
        m_vm->deleteFuture(this);
    }
}