diff --git a/source/exec.tex b/source/exec.tex index b84dcbfa36..9faabd6bb6 100644 --- a/source/exec.tex +++ b/source/exec.tex @@ -91,8 +91,8 @@ \item \tcode{err} if \tcode{decay_t} denotes the type \tcode{exception_ptr}. -\mandates -\tcode{err != exception_ptr()} is \tcode{true}. +\expects +\tcode{!err} is \tcode{false}. \item Otherwise, \tcode{make_exception_ptr(system_error(err))} @@ -229,7 +229,6 @@ representing the execution-time properties of the operation's caller. The caller of an asynchronous operation is its parent operation or the function that created it. -An asynchronous operation's operation state owns the operation's environment. \pnum An asynchronous operation has an associated receiver. @@ -1012,7 +1011,7 @@ -> @\libconcept{same_as}@>; } && @\libconcept{equality_comparable}@> && - @\libconcept{copy_constructible}@>; + @\libconcept{copyable}@>; } \end{codeblock} @@ -1025,17 +1024,15 @@ shall be modeled. \pnum -None of a scheduler's -copy constructor, -destructor, -equality comparison, or -\tcode{swap} member functions +No operation required by +\tcode{\libconcept{copyable}>} and +\tcode{\libconcept{equality_comparable}>} shall exit via an exception. -None of these member functions, +None of these operations, nor a scheduler type's \tcode{schedule} function, shall introduce data races as a result of potentially concurrent\iref{intro.races} invocations -of those functions from different threads. +of those operations from different threads. \pnum For any two values \tcode{sch1} and \tcode{sch2} @@ -1727,10 +1724,16 @@ \pnum The expression in the \tcode{noexcept} clause of -the constructor of \exposid{basic-state} is: +the constructor of \exposid{basic-state} is \begin{codeblock} is_nothrow_move_constructible_v && -@\exposconcept{nothrow-callable}@>::@\exposid{get-state}@), Sndr, Rcvr&> +@\exposconcept{nothrow-callable}@>::@\exposid{get-state}@), Sndr, Rcvr&> && +(same_as<@\exposid{state-type}@, @\exposid{get-state-result}@> || + is_nothrow_constructible_v<@\exposid{state-type}@, @\exposid{get-state-result}@>) +\end{codeblock} +where \exposid{get-state-result} is +\begin{codeblock} +@\exposid{call-result-t}@>::@\exposid{get-state}@), Sndr, Rcvr&>. \end{codeblock} \pnum @@ -1879,11 +1882,23 @@ struct @\exposid{impls-for}@<@\exposid{write-env-t}@> : @\exposid{default-impls}@ { static constexpr auto @\exposid{get-env}@ = [](auto, const auto& state, const auto& rcvr) noexcept { - return @\exposid{JOIN-ENV}@(state, get_env(rcvr)); + return @\seebelow@; }; }; \end{codeblock} \end{itemdescr} +Invocation of +\tcode{\exposid{impls-for}<\exposid{write-env-t}>::\exposid{get-env}} +returns an object \tcode{e} such that +\begin{itemize} +\item +\tcode{decltype(e)} models \libconcept{queryable} and +\item +given a query object \tcode{q}, +the expression \tcode{e.query(q)} is expression-equivalent +to \tcode{state.query(q)} if that expression is valid, +otherwise, \tcode{e.query(q)} is expression-equivalent +to \tcode{get_env(rcvr).query(q)}. \rSec2[exec.snd.concepts]{Sender concepts} @@ -2455,14 +2470,13 @@ Let \exposid{operation-state-task} be the following exposition-only class: \begin{codeblock} namespace std::execution { - struct @\exposid{operation-state-task}@ { + struct @\exposid{operation-state-task}@ { // \expos using operation_state_concept = operation_state_t; using promise_type = @\exposid{connect-awaitable-promise}@; explicit @\exposid{operation-state-task}@(coroutine_handle<> h) noexcept : coro(h) {} - @\exposid{operation-state-task}@(@\exposid{operation-state-task}@&& o) noexcept - : @\exposid{coro}@(exchange(o.@\exposid{coro}@, {})) {} - ~@\exposid{operation-state-task}@() { if (@\exposid{coro}@) @\exposid{coro}@.destroy(); } + @\exposid{operation-state-task}@(@\exposid{operation-state-task}@&&) = delete; + ~@\exposid{operation-state-task}@() { @\exposid{coro}@.destroy(); } void start() & noexcept { @\exposid{coro}@.resume(); @@ -3053,15 +3067,14 @@ using result_t = @\exposid{decayed-tuple}@; constexpr bool nothrow = is_nothrow_constructible_v; - @\exposid{TRY-EVAL}@(rcvr, [&]() noexcept(nothrow) { + try { state.@\exposid{async-result}@.template emplace(Tag(), std::forward(args)...); - }()); - - if (state.@\exposid{async-result}@.valueless_by_exception()) - return; - if (state.@\exposid{async-result}@.index() == 0) - return; - + } catch (...) { + if constexpr (!nothrow) { + set_error(std::move(rcvr), current_exception()); + return; + } + } start(state.@\exposid{op-state}@); }; \end{codeblock} @@ -3448,7 +3461,7 @@ } decltype(auto) get_env() const noexcept { - return @\exposid{JOIN-ENV}@(@\exposid{env}@, @\exposid{FWD-ENV}@(execution::get_env(@\exposid{rcvr}@))); + return @\seebelow@; } Rcvr& @\exposid{rcvr}@; // \expos @@ -3456,6 +3469,17 @@ }; } \end{codeblock} +Invocation of the function \tcode{\exposid{receiver2}::get_env} +returns an object \tcode{e} such that +\begin{itemize} +\item +\tcode{decltype(e)} models \libconcept{queryable} and +\item +given a query object \tcode{q}, +the expression \tcode{e.query(q)} is expression-equivalent +to \tcode{\exposid{env}.query(q)} if that expression is valid, +otherwise \tcode{e.query(q)} is expression-equivalent +to \tcode{get_env(\exposid{rcvr}).query(q)}. \pnum \tcode{\exposid{impls-for}<\exposid{decayed-typeof}<\exposid{let-cpo}>>::\exposid{get-state}} @@ -3647,7 +3671,7 @@ \item on a value completion operation, invokes \tcode{f(i, args...)} -for every \tcode{i} of type \tcode{Shape} from \tcode{0} to \tcode{shape}, +for every \tcode{i} of type \tcode{Shape} in \range{\tcode{0}}{\tcode{shape}}, where \tcode{args} is a pack of lvalue subexpressions referring to the value completion result datums of the input sender, and \item @@ -4101,10 +4125,20 @@ equivalent to the following lambda expression: \begin{codeblock} [](auto&&, State& state, const Receiver& rcvr) noexcept { - return @\exposid{JOIN-ENV}@( - @\exposid{MAKE-ENV}@(get_stop_token, state.@\exposid{stop_src}@.get_token()), get_env(rcvr)); + return @\seebelow@; } \end{codeblock} +Returns an object \tcode{e} such that +\begin{itemize} +\item +\tcode{decltype(e)} models \libconcept{queryable}, and +\item +\tcode{e.query(get_stop_token)} is expression-equivalent to +\tcode{state.\exposid{stop-src}.get_token()}, and +\item +given a query object \tcode{q} with type other than \cv{} \tcode{stop_token_t}, +\tcode{e.query(q)} is expression-equivalent to \tcode{get_env(rcvr).query(q)}. +\end{itemize} \pnum The member \tcode{\exposid{impls-for}::\exposid{get-state}} @@ -4957,7 +4991,8 @@ A \tcode{run_loop} instance has an associated \defn{count} that corresponds to the number of work items that are in its queue. Additionally, a \tcode{run_loop} instance has an associated state -that can be one of \defn{starting}, \defn{running}, or \defn{finishing}. +that can be one of +\defn{starting}, \defn{running}, \defn{finishing}, or \defn{finished}. \pnum Concurrent invocations of the member functions of \tcode{run_loop} @@ -5146,7 +5181,8 @@ \begin{itemize} \item \exposid{count} is \tcode{0} and \exposid{state} is \exposid{finishing}, -in which case \exposid{pop-front} returns \tcode{nullptr}; or +in which case \exposid{pop-front} sets \exposid{state} to \exposid{finished} +and returns \tcode{nullptr}; or \item \exposid{count} is greater than \tcode{0}, in which case an item is removed from the front of the queue, @@ -5191,11 +5227,14 @@ \begin{itemdescr} \pnum \expects -\exposid{state} is \exposid{starting}. +\exposid{state} is either \exposid{starting} or \exposid{finishing}. \pnum \effects -Sets the \exposid{state} to \exposid{running}. Then, equivalent to: +If \exposid{state} is \exposid{starting}, +sets the \exposid{state} to \exposid{running}, +otherwise leaves \exposid{state} unchanged. +Then, equivalent to: \begin{codeblock} while (auto* op = @\exposid{pop-front}@()) { op->@\exposid{execute}@(); @@ -5213,6 +5252,10 @@ \end{itemdecl} \begin{itemdescr} +\pnum +\expects +\exposid{state} is either \exposid{starting} or \exposid{running}. + \pnum \effects Changes \exposid{state} to \exposid{finishing}.