diff options
| -rw-r--r-- | lib/dialyzer/test/behaviour_SUITE_data/results/gen_server_incorrect_args | 2 | ||||
| -rw-r--r-- | lib/stdlib/doc/src/gen_server.xml | 52 | ||||
| -rw-r--r-- | lib/stdlib/src/gen_server.erl | 31 | ||||
| -rw-r--r-- | lib/stdlib/test/erl_internal_SUITE.erl | 4 | ||||
| -rw-r--r-- | lib/stdlib/test/gen_server_SUITE.erl | 111 | ||||
| -rw-r--r-- | lib/stdlib/test/gen_server_SUITE_data/oc_server.erl | 12 |
6 files changed, 185 insertions, 27 deletions
diff --git a/lib/dialyzer/test/behaviour_SUITE_data/results/gen_server_incorrect_args b/lib/dialyzer/test/behaviour_SUITE_data/results/gen_server_incorrect_args index 1eb8cd455b..1be0ce0d8c 100644 --- a/lib/dialyzer/test/behaviour_SUITE_data/results/gen_server_incorrect_args +++ b/lib/dialyzer/test/behaviour_SUITE_data/results/gen_server_incorrect_args @@ -1,5 +1,5 @@ gen_server_incorrect_args.erl:3: Undefined callback function handle_cast/2 (behaviour gen_server) gen_server_incorrect_args.erl:3: Undefined callback function init/1 (behaviour gen_server) -gen_server_incorrect_args.erl:7: The inferred return type of handle_call/3 ({'no'} | {'ok'}) has nothing in common with {'noreply',_} | {'noreply',_,'hibernate' | 'infinity' | non_neg_integer()} | {'reply',_,_} | {'stop',_,_} | {'reply',_,_,'hibernate' | 'infinity' | non_neg_integer()} | {'stop',_,_,_}, which is the expected return type for the callback of the gen_server behaviour +gen_server_incorrect_args.erl:7: The inferred return type of handle_call/3 ({'no'} | {'ok'}) has nothing in common with {'noreply',_} | {'noreply',_,'hibernate' | 'infinity' | non_neg_integer() | {'continue',_}} | {'reply',_,_} | {'stop',_,_} | {'reply',_,_,'hibernate' | 'infinity' | non_neg_integer() | {'continue',_}} | {'stop',_,_,_}, which is the expected return type for the callback of the gen_server behaviour gen_server_incorrect_args.erl:7: The inferred type for the 2nd argument of handle_call/3 ('boo' | 'foo') is not a supertype of {pid(),_}, which is expected type for this argument in the callback of the gen_server behaviour diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml index 7d137fc772..da74e793e6 100644 --- a/lib/stdlib/doc/src/gen_server.xml +++ b/lib/stdlib/doc/src/gen_server.xml @@ -60,6 +60,8 @@ gen_server:abcast -----> Module:handle_cast/2 - -----> Module:handle_info/2 +- -----> Module:handle_continue/2 + - -----> Module:terminate/2 - -----> Module:code_change/3</pre> @@ -88,6 +90,13 @@ gen_server:abcast -----> Module:handle_cast/2 implies at least two garbage collections (when hibernating and shortly after waking up) and is not something you want to do between each call to a busy server.</p> + + <p>If the <c>gen_server</c> process needs to perform an action + immediately after initialization or to break the execution of a + callback into multiple steps, it can return <c>{continue,Continue}</c> + in place of the time-out or hibernation value, which will immediately + invoke the <c>handle_continue/2</c> callback.</p> + </description> <funcs> @@ -610,12 +619,15 @@ gen_server:abcast -----> Module:handle_cast/2 <v>State = term()</v> <v>Result = {reply,Reply,NewState} | {reply,Reply,NewState,Timeout}</v> <v> | {reply,Reply,NewState,hibernate}</v> + <v> | {reply,Reply,NewState,{continue,Continue}}</v> <v> | {noreply,NewState} | {noreply,NewState,Timeout}</v> <v> | {noreply,NewState,hibernate}</v> + <v> | {noreply,NewState,{continue,Continue}}</v> <v> | {stop,Reason,Reply,NewState} | {stop,Reason,NewState}</v> <v> Reply = term()</v> <v> NewState = term()</v> <v> Timeout = int()>=0 | infinity</v> + <v> Continue = term()</v> <v> Reason = term()</v> </type> <desc> @@ -673,9 +685,11 @@ gen_server:abcast -----> Module:handle_cast/2 <v>State = term()</v> <v>Result = {noreply,NewState} | {noreply,NewState,Timeout}</v> <v> | {noreply,NewState,hibernate}</v> + <v> | {noreply,NewState,{continue,Continue}}</v> <v> | {stop,Reason,NewState}</v> <v> NewState = term()</v> <v> Timeout = int()>=0 | infinity</v> + <v> Continue = term()</v> <v> Reason = term()</v> </type> <desc> @@ -690,6 +704,41 @@ gen_server:abcast -----> Module:handle_cast/2 </func> <func> + <name>Module:handle_continue(Continue, State) -> Result</name> + <fsummary>Handle a continue instruction.</fsummary> + <type> + <v>Continue = term()</v> + <v>State = term()</v> + <v>Result = {noreply,NewState} | {noreply,NewState,Timeout}</v> + <v> | {noreply,NewState,hibernate}</v> + <v> | {noreply,NewState,{continue,Continue}}</v> + <v> | {stop,Reason,NewState}</v> + <v> NewState = term()</v> + <v> Timeout = int()>=0 | infinity</v> + <v> Continue = term()</v> + <v> Reason = normal | term()</v> + </type> + <desc> + <note> + <p>This callback is optional, so callback modules need to + export it only if they return <c>{continue,Continue}</c> + from another callback. If continue is used and the callback + is not implemented, the process will exit with <c>undef</c> + error.</p> + </note> + <p>This function is called by a <c>gen_server</c> process whenever + a previous callback returns <c>{continue, Continue}</c>. + <c>handle_continue/2</c> is invoked immediately after the previous + callback, which makes it useful for performing work after + initialization or for splitting the work in a callback in + multiple steps, updating the process state along the way.</p> + <p>For a description of the other arguments and possible return values, + see <seealso marker="#Module:handle_call/3"> + <c>Module:handle_call/3</c></seealso>.</p> + </desc> + </func> + + <func> <name>Module:handle_info(Info, State) -> Result</name> <fsummary>Handle an incoming message.</fsummary> <type> @@ -697,6 +746,7 @@ gen_server:abcast -----> Module:handle_cast/2 <v>State = term()</v> <v>Result = {noreply,NewState} | {noreply,NewState,Timeout}</v> <v> | {noreply,NewState,hibernate}</v> + <v> | {noreply,NewState,{continue,Continue}}</v> <v> | {stop,Reason,NewState}</v> <v> NewState = term()</v> <v> Timeout = int()>=0 | infinity</v> @@ -726,7 +776,7 @@ gen_server:abcast -----> Module:handle_cast/2 <type> <v>Args = term()</v> <v>Result = {ok,State} | {ok,State,Timeout} | {ok,State,hibernate}</v> - <v> | {stop,Reason} | ignore</v> + <v> | {ok,State,{continue,Continue}} | {stop,Reason} | ignore</v> <v> State = term()</v> <v> Timeout = int()>=0 | infinity</v> <v> Reason = term()</v> diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl index a3d53efd0d..48ef1c987a 100644 --- a/lib/stdlib/src/gen_server.erl +++ b/lib/stdlib/src/gen_server.erl @@ -116,23 +116,27 @@ %%%========================================================================= -callback init(Args :: term()) -> - {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate} | + {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate | {continue, term()}} | {stop, Reason :: term()} | ignore. -callback handle_call(Request :: term(), From :: {pid(), Tag :: term()}, State :: term()) -> {reply, Reply :: term(), NewState :: term()} | - {reply, Reply :: term(), NewState :: term(), timeout() | hibernate} | + {reply, Reply :: term(), NewState :: term(), timeout() | hibernate | {continue, term()}} | {noreply, NewState :: term()} | - {noreply, NewState :: term(), timeout() | hibernate} | + {noreply, NewState :: term(), timeout() | hibernate | {continue, term()}} | {stop, Reason :: term(), Reply :: term(), NewState :: term()} | {stop, Reason :: term(), NewState :: term()}. -callback handle_cast(Request :: term(), State :: term()) -> {noreply, NewState :: term()} | - {noreply, NewState :: term(), timeout() | hibernate} | + {noreply, NewState :: term(), timeout() | hibernate | {continue, term()}} | {stop, Reason :: term(), NewState :: term()}. -callback handle_info(Info :: timeout | term(), State :: term()) -> {noreply, NewState :: term()} | - {noreply, NewState :: term(), timeout() | hibernate} | + {noreply, NewState :: term(), timeout() | hibernate | {continue, term()}} | + {stop, Reason :: term(), NewState :: term()}. +-callback handle_continue(Info :: term(), State :: term()) -> + {noreply, NewState :: term()} | + {noreply, NewState :: term(), timeout() | hibernate | {continue, term()}} | {stop, Reason :: term(), NewState :: term()}. -callback terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()), @@ -149,7 +153,7 @@ Status :: term(). -optional_callbacks( - [handle_info/2, terminate/2, code_change/3, format_status/2]). + [handle_info/2, handle_continue/2, terminate/2, code_change/3, format_status/2]). %%% ----------------------------------------------------------------- %%% Starts a generic server. @@ -309,7 +313,7 @@ enter_loop(Mod, Options, State, ServerName, Timeout) -> Name = gen:get_proc_name(ServerName), Parent = gen:get_parent(), Debug = gen:debug_options(Name, Options), - HibernateAfterTimeout = gen:hibernate_after(Options), + HibernateAfterTimeout = gen:hibernate_after(Options), loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug). %%%======================================================================== @@ -374,6 +378,19 @@ init_it(Mod, Args) -> %%% --------------------------------------------------- %%% The MAIN loop. %%% --------------------------------------------------- + +loop(Parent, Name, State, Mod, {continue, Continue} = Msg, HibernateAfterTimeout, Debug) -> + Reply = try_dispatch(Mod, handle_continue, Continue, State), + case Debug of + [] -> + handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, + HibernateAfterTimeout, State); + _ -> + Debug1 = sys:handle_debug(Debug, fun print_event/3, Name, Msg), + handle_common_reply(Reply, Parent, Name, undefined, Msg, Mod, + HibernateAfterTimeout, State, Debug1) + end; + loop(Parent, Name, State, Mod, hibernate, HibernateAfterTimeout, Debug) -> proc_lib:hibernate(?MODULE,wake_hib,[Parent, Name, State, Mod, HibernateAfterTimeout, Debug]); diff --git a/lib/stdlib/test/erl_internal_SUITE.erl b/lib/stdlib/test/erl_internal_SUITE.erl index 789a9d4363..7d9df1f989 100644 --- a/lib/stdlib/test/erl_internal_SUITE.erl +++ b/lib/stdlib/test/erl_internal_SUITE.erl @@ -80,7 +80,7 @@ callbacks(application) -> callbacks(gen_server) -> [{init,1}, {handle_call,3}, {handle_cast,2}, {handle_info,2}, {terminate,2}, {code_change,3}, - {format_status,2}]; + {format_status,2}, {handle_continue, 2}]; callbacks(gen_fsm) -> [{init,1}, {handle_event,3}, {handle_sync_event,4}, {handle_info,3}, {terminate,3}, {code_change,4}, @@ -101,7 +101,7 @@ callbacks(supervisor) -> optional_callbacks(application) -> []; optional_callbacks(gen_server) -> - [{handle_info, 2}, {terminate, 2}, {code_change, 3}, {format_status, 2}]; + [{handle_info, 2}, {handle_continue, 2}, {terminate, 2}, {code_change, 3}, {format_status, 2}]; optional_callbacks(gen_fsm) -> [{handle_info, 3}, {terminate, 3}, {code_change, 4}, {format_status, 2}]; optional_callbacks(gen_event) -> diff --git a/lib/stdlib/test/gen_server_SUITE.erl b/lib/stdlib/test/gen_server_SUITE.erl index 2e9dc4d4fb..2bc220fef2 100644 --- a/lib/stdlib/test/gen_server_SUITE.erl +++ b/lib/stdlib/test/gen_server_SUITE.erl @@ -27,7 +27,7 @@ -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, init_per_group/2,end_per_group/2]). -export([start/1, crash/1, call/1, cast/1, cast_fast/1, - info/1, abcast/1, multicall/1, multicall_down/1, + continue/1, info/1, abcast/1, multicall/1, multicall_down/1, call_remote1/1, call_remote2/1, call_remote3/1, call_remote_n1/1, call_remote_n2/1, call_remote_n3/1, spec_init/1, spec_init_local_registered_parent/1, @@ -37,7 +37,8 @@ get_state/1, replace_state/1, call_with_huge_message_queue/1, undef_handle_call/1, undef_handle_cast/1, undef_handle_info/1, undef_init/1, undef_code_change/1, undef_terminate1/1, - undef_terminate2/1, undef_in_terminate/1, undef_in_handle_info/1 + undef_terminate2/1, undef_in_terminate/1, undef_in_handle_info/1, + undef_handle_continue/1 ]). -export([stop1/1, stop2/1, stop3/1, stop4/1, stop5/1, stop6/1, stop7/1, @@ -52,7 +53,7 @@ %% The gen_server behaviour --export([init/1, handle_call/3, handle_cast/2, +-export([init/1, handle_call/3, handle_cast/2, handle_continue/2, handle_info/2, code_change/3, terminate/2, format_status/2]). suite() -> @@ -61,7 +62,7 @@ suite() -> all() -> [start, {group,stop}, crash, call, cast, cast_fast, info, abcast, - multicall, multicall_down, call_remote1, call_remote2, + continue, multicall, multicall_down, call_remote1, call_remote2, call_remote3, call_remote_n1, call_remote_n2, call_remote_n3, spec_init, spec_init_local_registered_parent, @@ -76,7 +77,7 @@ groups() -> [{stop, [], [stop1, stop2, stop3, stop4, stop5, stop6, stop7, stop8, stop9, stop10]}, {undef_callbacks, [], - [undef_handle_call, undef_handle_cast, undef_handle_info, + [undef_handle_call, undef_handle_cast, undef_handle_info, undef_handle_continue, undef_init, undef_code_change, undef_terminate1, undef_terminate2]}]. @@ -458,6 +459,47 @@ call(Config) when is_list(Config) -> ok. %% -------------------------------------- +%% Test handle_continue. +%% -------------------------------------- + +continue(Config) when is_list(Config) -> + {ok, Pid} = gen_server:start_link(gen_server_SUITE, {continue, self()}, []), + [{Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + gen_server:call(Pid, {continue_reply, self()}), + [{Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + gen_server:call(Pid, {continue_noreply, self()}), + [{Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + gen_server:cast(Pid, {continue_noreply, self()}), + [{Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + Pid ! {continue_noreply, self()}, + [{Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + Pid ! {continue_continue, self()}, + [{Pid, before_continue}, {Pid, continue}, {Pid, after_continue}] = read_replies(Pid), + + Ref = monitor(process, Pid), + Pid ! continue_stop, + verify_down_reason(Ref, Pid, normal). + +read_replies(Pid) -> + receive + {Pid, ack} -> read_replies() + after + 1000 -> ct:fail({continue, ack}) + end. + +read_replies() -> + receive + Msg -> [Msg | read_replies()] + after + 0 -> [] + end. + +%% -------------------------------------- %% Test call to nonexisting processes on remote nodes %% -------------------------------------- @@ -1346,7 +1388,7 @@ echo_loop() -> %% Test the default implementation of terminate if the callback module %% does not export it undef_terminate1(Config) when is_list(Config) -> - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), MRef = monitor(process, Server), ok = gen_server:stop(Server), ok = verify_down_reason(MRef, Server, normal). @@ -1354,7 +1396,7 @@ undef_terminate1(Config) when is_list(Config) -> %% Test the default implementation of terminate if the callback module %% does not export it undef_terminate2(Config) when is_list(Config) -> - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), MRef = monitor(process, Server), ok = gen_server:stop(Server, {error, test}, infinity), ok = verify_down_reason(MRef, Server, {error, test}). @@ -1377,7 +1419,7 @@ undef_init(_Config) -> %% The upgrade should fail if code_change is expected in the callback module %% but not exported, but the server should continue with the old code undef_code_change(Config) when is_list(Config) -> - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), {error, {'EXIT', {undef, [{oc_server, code_change, [_, _, _], _}|_]}}} = fake_upgrade(Server, ?MODULE), true = is_process_alive(Server). @@ -1385,7 +1427,7 @@ undef_code_change(Config) when is_list(Config) -> %% The server should crash if the handle_call callback is %% not exported in the callback module undef_handle_call(_Config) -> - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), try gen_server:call(Server, call_msg), ct:fail(should_crash) @@ -1397,17 +1439,25 @@ undef_handle_call(_Config) -> %% The server should crash if the handle_cast callback is %% not exported in the callback module undef_handle_cast(_Config) -> - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), MRef = monitor(process, Server), gen_server:cast(Server, cast_msg), verify_undef_down(MRef, Server, oc_server, handle_cast), ok. +%% The server should crash if the handle_continue callback is +%% not exported in the callback module +undef_handle_continue(_Config) -> + {ok, Server} = oc_server:start(continue), + MRef = monitor(process, Server), + verify_undef_down(MRef, Server, oc_server, handle_continue), + ok. + %% The server should log but not crash if the handle_info callback is %% calling an undefined function undef_handle_info(Config) when is_list(Config) -> error_logger_forwarder:register(), - {ok, Server} = gen_server:start(oc_server, [], []), + {ok, Server} = oc_server:start(), Server ! hej, wait_until_processed(Server, hej, 10), true = is_process_alive(Server), @@ -1570,8 +1620,11 @@ init(hibernate) -> init(sleep) -> ct:sleep(1000), {ok, []}; +init({continue, Pid}) -> + self() ! {after_continue, Pid}, + {ok, [], {continue, {message, Pid}}}; init({state,State}) -> - {ok, State}. + {ok,State}. handle_call(started_p, _From, State) -> io:format("FROZ"), @@ -1604,6 +1657,12 @@ handle_call(shutdown_reason, _From, _State) -> handle_call({call_undef_fun, Mod, Fun}, _From, State) -> Mod:Fun(), {reply, ok, State}; +handle_call({continue_reply, Pid}, _From, State) -> + self() ! {after_continue, Pid}, + {reply, ok, State, {continue, {message, Pid}}}; +handle_call({continue_noreply, Pid}, From, State) -> + self() ! {after_continue, Pid}, + {noreply, State, {continue, {message, Pid, From}}}; handle_call(stop_shutdown_reason, _From, State) -> {stop,{shutdown,stop_reason},State}. @@ -1620,6 +1679,9 @@ handle_cast(hibernate_later, _State) -> handle_cast({call_undef_fun, Mod, Fun}, State) -> Mod:Fun(), {noreply, State}; +handle_cast({continue_noreply, Pid}, State) -> + self() ! {after_continue, Pid}, + {noreply, State, {continue, {message, Pid}}}; handle_cast({From, stop}, State) -> io:format("BAZ"), {stop, {From,stopped}, State}. @@ -1657,9 +1719,34 @@ handle_info(continue, From) -> {noreply, []}; handle_info({From, stop}, State) -> {stop, {From,stopped_info}, State}; +handle_info({after_continue, Pid}, State) -> + Pid ! {self(), after_continue}, + Pid ! {self(), ack}, + {noreply, State}; +handle_info({continue_noreply, Pid}, State) -> + self() ! {after_continue, Pid}, + {noreply, State, {continue, {message, Pid}}}; +handle_info({continue_continue, Pid}, State) -> + {noreply, State, {continue, {continue, Pid}}}; +handle_info(continue_stop, State) -> + {noreply, State, {continue, stop}}; handle_info(_Info, State) -> {noreply, State}. +handle_continue({continue, Pid}, State) -> + Pid ! {self(), before_continue}, + self() ! {after_continue, Pid}, + {noreply, State, {continue, {message, Pid}}}; +handle_continue(stop, State) -> + {stop, normal, State}; +handle_continue({message, Pid}, State) -> + Pid ! {self(), continue}, + {noreply, State}; +handle_continue({message, Pid, From}, State) -> + Pid ! {self(), continue}, + gen_server:reply(From, ok), + {noreply, State}. + code_change(_OldVsn, {new, {undef_in_code_change, {Mod, Fun}}} = State, _Extra) -> diff --git a/lib/stdlib/test/gen_server_SUITE_data/oc_server.erl b/lib/stdlib/test/gen_server_SUITE_data/oc_server.erl index 4ba37987f3..7b92a49bf6 100644 --- a/lib/stdlib/test/gen_server_SUITE_data/oc_server.erl +++ b/lib/stdlib/test/gen_server_SUITE_data/oc_server.erl @@ -22,7 +22,7 @@ -behaviour(gen_server). %% API --export([start/0]). +-export([start/0, start/1]). %% gen_server callbacks -export([init/1]). @@ -30,8 +30,12 @@ -record(state, {}). start() -> - gen_server:start({local, ?MODULE}, ?MODULE, [], []). + gen_server:start(?MODULE, ok, []). -init([]) -> - {ok, #state{}}. +start(continue) -> + gen_server:start(?MODULE, continue, []). +init(ok) -> + {ok, #state{}}; +init(continue) -> + {ok, #state{}, {continue, continue}}. |