/* RPC call and callback templates
- Copyright (C) 2014-2021 Free Software Foundation, Inc.
+ Copyright (C) 2014-2023 Free Software Foundation, Inc.
This file is part of GCC.
argument_wrapper (const argument_wrapper &) = delete;
argument_wrapper &operator= (const argument_wrapper &) = delete;
- operator T () const { return m_object; }
+ T get () const { return m_object; }
status unmarshall (connection *conn)
{
typedef typename std::remove_const<T>::type type;
- operator const type * () const
+ const type *get () const
{
return m_object.get ();
}
};
// There are two kinds of template functions here: "call" and
- // "callback". "call" is implemented with variadic templates, but
- // "callback" is repeated multiple times to handle different numbers
- // of arguments. (This could be improved with C++17 and
- // std::apply.)
+ // "invoker".
// The "call" template is used for making a remote procedure call.
// It starts a query ('Q') packet, marshalls its arguments, waits
// for a result, and finally reads and returns the result via an
// "out" parameter.
- // The "callback" template is used when receiving a remote procedure
+ // The "invoker" template is used when receiving a remote procedure
// call. This template function is suitable for use with the
// "callbacks" and "connection" classes. It decodes incoming
// arguments, passes them to the wrapped function, and finally
return OK;
}
- template<typename R, R (*func) (connection *)>
- status
- callback (connection *conn)
+ // The base case -- just return OK.
+ template<int I, typename... T>
+ typename std::enable_if<I == sizeof... (T), status>::type
+ unmarshall (connection *, std::tuple<T...> &)
{
- R result;
-
- if (!unmarshall_check (conn, 0))
- return FAIL;
- result = func (conn);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
- }
-
- template<typename R, typename A, R (*func) (connection *, A)>
- status
- callback (connection *conn)
- {
- argument_wrapper<A> arg;
- R result;
-
- if (!unmarshall_check (conn, 1))
- return FAIL;
- if (!arg.unmarshall (conn))
- return FAIL;
- result = func (conn, arg);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
+ return OK;
}
- template<typename R, typename A1, typename A2, R (*func) (connection *,
- A1, A2)>
- status
- callback (connection *conn)
+ // Unmarshall this argument, then unmarshall all subsequent args.
+ template<int I, typename... T>
+ typename std::enable_if<I < sizeof... (T), status>::type
+ unmarshall (connection *conn, std::tuple<T...> &value)
{
- argument_wrapper<A1> arg1;
- argument_wrapper<A2> arg2;
- R result;
-
- if (!unmarshall_check (conn, 2))
- return FAIL;
- if (!arg1.unmarshall (conn))
- return FAIL;
- if (!arg2.unmarshall (conn))
+ if (!std::get<I> (value).unmarshall (conn))
return FAIL;
- result = func (conn, arg1, arg2);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
+ return unmarshall<I + 1, T...> (conn, value);
}
- template<typename R, typename A1, typename A2, typename A3,
- R (*func) (connection *, A1, A2, A3)>
- status
- callback (connection *conn)
+ // Wrap a static function that is suitable for use as a callback.
+ // This is a template function inside a template class to work
+ // around limitations with multiple variadic packs.
+ template<typename R, typename... Arg>
+ class invoker
{
- argument_wrapper<A1> arg1;
- argument_wrapper<A2> arg2;
- argument_wrapper<A3> arg3;
- R result;
+ // Base case -- we can call the function.
+ template<int I, R func (connection *, Arg...), typename... T>
+ static typename std::enable_if<I == sizeof... (Arg), R>::type
+ call (connection *conn, const std::tuple<argument_wrapper<Arg>...> &,
+ T... args)
+ {
+ return func (conn, args...);
+ }
- if (!unmarshall_check (conn, 3))
- return FAIL;
- if (!arg1.unmarshall (conn))
- return FAIL;
- if (!arg2.unmarshall (conn))
- return FAIL;
- if (!arg3.unmarshall (conn))
- return FAIL;
- result = func (conn, arg1, arg2, arg3);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
- }
+ // Unpack one argument and continue the recursion.
+ template<int I, R func (connection *, Arg...), typename... T>
+ static typename std::enable_if<I < sizeof... (Arg), R>::type
+ call (connection *conn, const std::tuple<argument_wrapper<Arg>...> &value,
+ T... args)
+ {
+ return call<I + 1, func> (conn, value, args...,
+ std::get<I> (value).get ());
+ }
- template<typename R, typename A1, typename A2, typename A3, typename A4,
- R (*func) (connection *, A1, A2, A3, A4)>
- status
- callback (connection *conn)
- {
- argument_wrapper<A1> arg1;
- argument_wrapper<A2> arg2;
- argument_wrapper<A3> arg3;
- argument_wrapper<A4> arg4;
- R result;
+ public:
- if (!unmarshall_check (conn, 4))
- return FAIL;
- if (!arg1.unmarshall (conn))
- return FAIL;
- if (!arg2.unmarshall (conn))
- return FAIL;
- if (!arg3.unmarshall (conn))
- return FAIL;
- if (!arg4.unmarshall (conn))
- return FAIL;
- result = func (conn, arg1, arg2, arg3, arg4);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
- }
+ // A callback function that reads arguments from the connection,
+ // calls the wrapped function, and then sends the result back on
+ // the connection.
+ template<R func (connection *, Arg...)>
+ static status
+ invoke (connection *conn)
+ {
+ if (!unmarshall_check (conn, sizeof... (Arg)))
+ return FAIL;
+ std::tuple<argument_wrapper<Arg>...> wrapped;
+ if (!unmarshall<0> (conn, wrapped))
+ return FAIL;
- template<typename R, typename A1, typename A2, typename A3, typename A4,
- typename A5, R (*func) (connection *, A1, A2, A3, A4, A5)>
- status
- callback (connection *conn)
- {
- argument_wrapper<A1> arg1;
- argument_wrapper<A2> arg2;
- argument_wrapper<A3> arg3;
- argument_wrapper<A4> arg4;
- argument_wrapper<A5> arg5;
- R result;
-
- if (!unmarshall_check (conn, 5))
- return FAIL;
- if (!arg1.unmarshall (conn))
- return FAIL;
- if (!arg2.unmarshall (conn))
- return FAIL;
- if (!arg3.unmarshall (conn))
- return FAIL;
- if (!arg4.unmarshall (conn))
- return FAIL;
- if (!arg5.unmarshall (conn))
- return FAIL;
- result = func (conn, arg1, arg2, arg3, arg4, arg5);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
- }
+ R result = call<0, func> (conn, wrapped);
- template<typename R, typename A1, typename A2, typename A3, typename A4,
- typename A5, typename A6, typename A7,
- R (*func) (connection *, A1, A2, A3, A4, A5, A6, A7)>
- status
- callback (connection *conn)
- {
- argument_wrapper<A1> arg1;
- argument_wrapper<A2> arg2;
- argument_wrapper<A3> arg3;
- argument_wrapper<A4> arg4;
- argument_wrapper<A5> arg5;
- argument_wrapper<A6> arg6;
- argument_wrapper<A7> arg7;
- R result;
-
- if (!unmarshall_check (conn, 7))
- return FAIL;
- if (!arg1.unmarshall (conn))
- return FAIL;
- if (!arg2.unmarshall (conn))
- return FAIL;
- if (!arg3.unmarshall (conn))
- return FAIL;
- if (!arg4.unmarshall (conn))
- return FAIL;
- if (!arg5.unmarshall (conn))
- return FAIL;
- if (!arg6.unmarshall (conn))
- return FAIL;
- if (!arg7.unmarshall (conn))
- return FAIL;
- result = func (conn, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
- if (!conn->send ('R'))
- return FAIL;
- return marshall (conn, result);
- }
+ if (!conn->send ('R'))
+ return FAIL;
+ return marshall (conn, result);
+ }
+ };
};
#endif // CC1_PLUGIN_RPC_HH
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