diff options
Diffstat (limited to 'lib/stdlib/src/gen.erl')
| -rw-r--r-- | lib/stdlib/src/gen.erl | 72 |
1 files changed, 70 insertions, 2 deletions
diff --git a/lib/stdlib/src/gen.erl b/lib/stdlib/src/gen.erl index 33af0aed8f..bb40798ba1 100644 --- a/lib/stdlib/src/gen.erl +++ b/lib/stdlib/src/gen.erl @@ -28,7 +28,9 @@ %%%----------------------------------------------------------------- -export([start/5, start/6, debug_options/2, hibernate_after/1, name/1, unregister_name/1, get_proc_name/1, get_parent/0, - call/3, call/4, reply/2, stop/1, stop/3]). + call/3, call/4, reply/2, + async_call/3, yield/1, yield/2, + stop/1, stop/3]). -export([init_it/6, init_it/7]). @@ -52,6 +54,11 @@ | {'spawn_opt', [proc_lib:spawn_option()]}. -type options() :: [option()]. +-type server_ref() :: pid() | atom() | {atom(), node()} + | {global, term()} | {via, module(), term()}. + +-type promise() :: reference(). + %%----------------------------------------------------------------- %% Starts a generic process. %% start(GenMod, LinkP, Mod, Args, Options) @@ -138,7 +145,7 @@ init_it2(GenMod, Starter, Parent, Name, Mod, Args, Options) -> %%----------------------------------------------------------------- %% Makes a synchronous call to a generic process. %% Request is sent to the Pid, and the response must be -%% {Tag, _, Reply}. +%% {Tag, Reply}. %%----------------------------------------------------------------- %%% New call function which uses the new monitor BIF @@ -225,6 +232,67 @@ wait_resp(Node, Tag, Timeout) -> exit(timeout) end. +-spec async_call(Name::server_ref(), Label::term(), Request::term()) -> promise(). +async_call(Process, Label, Request) when is_pid(Process); is_atom(Process) -> + do_async_call(Process, Label, Request); +async_call({Name, _}=Process, Label, Request) + when is_atom(Name), Name =/= global -> + do_async_call(Process, Label, Request); +async_call(Process, Label, Request) -> + try where(Process) of + Pid when is_pid(Pid) -> + do_async_call(Pid, Label, Request); + undefined -> + Ref = erlang:make_ref(), + self() ! {'DOWN', Ref, process, Process, noproc}, + Ref + catch _:_ -> + error({badarg,Process}) + end. + +do_async_call(Process, Label, Request) -> + try erlang:monitor(process, Process) of + Mref -> + %% If the monitor/2 call failed to set up a connection to a + %% remote node, we don't want the '!' operator to attempt + %% to set up the connection again. (If the monitor/2 call + %% failed due to an expired timeout, '!' too would probably + %% have to wait for the timeout to expire.) Therefore, + %% use erlang:send/3 with the 'noconnect' option so that it + %% will fail immediately if there is no connection to the + %% remote node. + catch erlang:send(Process, {Label, {self(), Mref}, Request}, + [noconnect]), + Mref + catch + %% Do not support erl_interface or other systems which + %% non don't have monitor supported + error:_ -> error({badarg, Process}) + end. + +%% +%% Wait for a reply to the client. +%% Note: if timeout is returned monitors are kept. + +-spec yield(Key::promise()) -> {ok, Reply::term()}. +yield(Key) -> + yield(Key, infinity). + +-spec yield(Key::promise(), timeout()) -> {reply, Reply::term()} | 'timeout'. +yield(Mref, Timeout) -> + receive + {Mref, Reply} -> + erlang:demonitor(Mref, [flush]), + {reply, Reply}; + {'DOWN', Mref, _, Pid, noconnection} when is_pid(Pid) -> + exit({nodedown, node(Pid)}); + {'DOWN', Mref, _, {_, Node}, noconnection} -> + exit({nodedown, Node}); + {'DOWN', Mref, _, _, Reason} -> + exit(Reason) + after Timeout -> timeout + end. + %% %% Send a reply to the client. %% |