- the lambda posted inside iasio::rond_robin will be shared by different
threads running io_service::run()
- the lambda must remain/executed by the thread
- re-introduction of run_svc() method
Given the necessity for fibers::asio::round_robin to share its ready queue
among all threads calling io_service::run() on the same io_service instance,
the capability to allow hop (or not) in the fibers::asio::yield mechanism is
redundant.
If the async operation invoked by the asio async function immediately calls
yield_handler_base::operator() even before control reaches
async_result_base::get(), which would suspend the calling fiber, the context*
bound by yield_handler_base's constructor is still the active() context. This
may not be passed to context::migrate(). It probably shouldn't be passed to
context::set_ready(), either.
The whole yield / yield_hop dichotomy becomes much easier to read and explain
if we stick to a single yield_t class. Since the intention is for a consumer
to pass canonical instances rather than manipulating that class in any other
way, we can instantiate it however we want.
This gets rid of lots of ugly redundant boost::asio::handler_type<>
specializations.
Introduce yield_base with subclasses yield_t and yield_hop_t, each with a
canonical instance yield and yield_hop. yield_base adds allow_hop_ bool to
communicate the distinction to yield_handler: yield_t sets false, yield_hop_t
sets true.
Extract common base class yield_handler_base from yield_handler<T> and
yield_handler<void>. In fact yield_handler_base is almost identical to
yield_handler<void>; yield_handler<T> adds value processing.
Instead of capturing just the error_code* from the passed yield_base instance,
capture the whole yield_base: both its error_code* and the new allow_hop_ bool.
yield_handler_base provides operator()(error_code) method. This operator()
sets a new completed_ bool so calling fiber need NOT suspend if the async
operation completes immediately. That bool must be defended with a mutex.
This operator() also avoids migrating a pinned_context, or when a caller
passes plain yield instead of yield_hop.
New wait() method suspends the calling fiber only if (! completed_).
Extract common base class async_result_base from async_result<T> and
async_result<void>. In fact async_result_base is almost identical to
async_result<void>; async_result<T> adds value processing.
Add handler_type<> specializations for new yield_base and yield_hop_t
completion token types.
Now that rqueue_ is an STL-compatible container,
priority_scheduler::awakened() can use std::find_if() to search for a context
with a lower priority.
Now that rqueue_ is an intrusive_list, priority_scheduler::property_change()
need not search it: it can simply test with context::ready_is_linked(). Now
that it's a doubly-linked list, we can use context::ready_unlink() to unlink.
Now that method parameters have been renamed from 'f' to 'ctx', change all
references in comments accordingly.
Highlight predicate condition_variable::wait() method in condition_variable
front matter.
Rewrite the explanation of wait()'s Precondition.
Add a condition_variables subsection about no spurious condition_variable
wakeups. Remove "or spuriously" from wakeup conditions in wait*() methods.
First pass through "spurious wakeup" section in Rationale.
First pass through migration.qbk. Use lock_t throughout work_sharing.cpp,
instead of lock_t, lock_count and explicit std::unique_lock<std::mutex>
declarations. Unify treatment of main and dispatcher fibers.
Clarify thread-safety requirements on sched_algorithm::notify() and
suspend_until().
Clarify disable_interruption when rethrowing fiber_interrupted.
Consolidate future<T>::get(): returns T whether T is R, R& or void.
Mention nesting of disable_interruption (which matters) versus nesting of
restore_interruption (which doesn't). Mention that a disable_interruption
constructed within the scope of another disable_interruption is a no-op, both
itself and when passed to restore_interruption.
When packaged_task::operator()() stores a value or an exception, state "as if"
by promise::set_value() or set_exception(): the shared state is set ready.
Similarly for ~packaged_task() and ~promise() setting broken_promise.
Sprinkle links to the Allocator concept, std::allocator and
std::allocator_arg_t where referenced. Similarly for StackAllocator.
Add more cross-reference links where Fiber classes and methods are mentioned.
Also things like std::unique_lock and std::mutex.
Clarify error condition for value_pop() when channel is close()d.
Since fiber_specific_ptr::release() does not invoke cleanup, it should not
throw an exception raised during cleanup.
Note effect of BOOST_USE_SEGMENTED_STACKS if StackAllocator is not explicitly
passed.
Introduce function_heading_for QuickBook template to allow separate
descriptions of swap(fiber), swap(packaged_task) and swap(promise).
Document async() using C++14 std::result_of_t and std::decay_t, aligning with
std::async() documentation.
Rework when_any / when_all examples to use unbounded_channel throughout, since
we always close() the channel after the first value anyway. bounded_channel
doesn't really add much value here.
Make wait_first_outcome_impl() infer its channel pointer type. That way we can
reuse that function instead of coding a separate wait_all_until_error_impl(),
which differs only in using the nchannel facade instead of directly pushing to
unbounded_channel.
Explain use of std::bind() to bind a lambda.
Use a more nuanced discussion of promise lifetime in write_ec() example
function.
Use condition_variable::wait(lock, predicate) in a couple places in
work_sharing.cpp example.
