-callbacks for gen_server2. USE_SPECS now requires R15B.

2 files changed, 56 insertions, 11 deletions

diff --git a/Makefile b/Makefile
index e8975856..93763400 100644
--- a/Makefile
+++ b/Makefile
@@ -42,9 +42,9 @@ BASIC_PLT=basic.plt
 RABBIT_PLT=rabbit.plt
 
 ifndef USE_SPECS
-# our type specs rely on features and bug fixes in dialyzer that are
-# only available in R14B03 upwards (R14B03 is erts 5.8.4)
-USE_SPECS:=$(shell erl -noshell -eval 'io:format([list_to_integer(X) || X <- string:tokens(erlang:system_info(version), ".")] >= [5,8,4]), halt().')
+# our type specs rely on callback specs, which are available in R15B
+# upwards.
+USE_SPECS:=$(shell erl -noshell -eval 'io:format([list_to_integer(X) || X <- string:tokens(erlang:system_info(version), ".")] >= [5,9]), halt().')
 endif
 
 ifndef USE_PROPER_QC
diff --git a/src/gen_server2.erl b/src/gen_server2.erl
index f8537487..765009ff 100644
--- a/src/gen_server2.erl
+++ b/src/gen_server2.erl
@@ -31,13 +31,13 @@
 %% handle_pre_hibernate/1 then the default action is to hibernate.
 %%
 %% 6) init can return a 4th arg, {backoff, InitialTimeout,
-%% MinimumTimeout, DesiredHibernatePeriod} (all in
-%% milliseconds). Then, on all callbacks which can return a timeout
-%% (including init), timeout can be 'hibernate'. When this is the
-%% case, the current timeout value will be used (initially, the
-%% InitialTimeout supplied from init). After this timeout has
-%% occurred, hibernation will occur as normal. Upon awaking, a new
-%% current timeout value will be calculated.
+%% MinimumTimeout, DesiredHibernatePeriod} (all in milliseconds,
+%% 'infinity' does not make sense here). Then, on all callbacks which
+%% can return a timeout (including init), timeout can be
+%% 'hibernate'. When this is the case, the current timeout value will
+%% be used (initially, the InitialTimeout supplied from init). After
+%% this timeout has occurred, hibernation will occur as normal. Upon
+%% awaking, a new current timeout value will be calculated.
 %%
 %% The purpose is that the gen_server2 takes care of adjusting the
 %% current timeout value such that the process will increase the
@@ -135,9 +135,10 @@
 %%%              Reason = normal | shutdown | Term, terminate(State) is called
 %%%
 %%%   terminate(Reason, State) Let the user module clean up
+%%%              Reason = normal | shutdown | {shutdown, Term} | Term
 %%%        always called when server terminates
 %%%
-%%%    ==> ok
+%%%    ==> ok | Term
 %%%
 %%%   handle_pre_hibernate(State)
 %%%
@@ -182,7 +183,9 @@
          multi_call/2, multi_call/3, multi_call/4,
          enter_loop/3, enter_loop/4, enter_loop/5, enter_loop/6, wake_hib/1]).
 
+-ifndef(use_specs).
 -export([behaviour_info/1]).
+-endif.
 
 %% System exports
 -export([system_continue/3,
@@ -220,12 +223,54 @@
 %%%  API
 %%%=========================================================================
 
+-ifdef(use_specs).
+
+-type(millis() :: non_neg_integer()).
+
+-callback init(Args :: term()) ->
+    {ok, State :: term()} |
+    {ok, State :: term(), timeout() | hibernate} |
+    {ok, State :: term(), timeout() | hibernate,
+     {backoff, millis(), millis(), millis()}} |
+    ignore |
+    {stop, Reason :: term()}.
+-callback handle_call(Request :: term(), From :: {pid(), Tag :: term()},
+                      State :: term()) ->
+    {reply, Reply :: term(), NewState :: term()} |
+    {reply, Reply :: term(), NewState :: term(), timeout() | hibernate} |
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(),
+     Reply :: term(), NewState :: term()}.
+-callback handle_cast(Request :: term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+-callback handle_info(Info :: term(), State :: term()) ->
+    {noreply, NewState :: term()} |
+    {noreply, NewState :: term(), timeout() | hibernate} |
+    {stop, Reason :: term(), NewState :: term()}.
+-callback terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
+                    State :: term()) ->
+    (ok | term()).
+-callback code_change(OldVsn :: (term() | {down, term()}), State :: term(),
+                      Extra :: term()) ->
+    {ok, NewState :: term()} | {error, Reason :: term()}.
+
+%% It's not possible to define "optional" -callbacks, so putting specs
+%% for handle_pre_hibernate/1 and handle_post_hibernate/1 will result
+%% in warnings (the same applied for the behaviour_info before).
+
+-else.
+
 behaviour_info(callbacks) ->
     [{init,1},{handle_call,3},{handle_cast,2},{handle_info,2},
      {terminate,2},{code_change,3}];
 behaviour_info(_Other) ->
     undefined.
 
+-endif.
+
 %%%  -----------------------------------------------------------------
 %%% Starts a generic server.
 %%% start(Mod, Args, Options)