%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1998-2009. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(seq_trace).
-define(SEQ_TRACE_SEND, 1). %(1 << 0)
-define(SEQ_TRACE_RECEIVE, 2). %(1 << 1)
-define(SEQ_TRACE_PRINT, 4). %(1 << 2)
-define(SEQ_TRACE_TIMESTAMP, 8). %(1 << 3)
-export([set_token/1,
set_token/2,
get_token/0,
get_token/1,
print/1,
print/2,
reset_trace/0,
set_system_tracer/1,
get_system_tracer/0]).
%%---------------------------------------------------------------------------
-type flag() :: 'send' | 'receive' | 'print' | 'timestamp'.
-type component() :: 'label' | 'serial' | flag().
-type value() :: non_neg_integer()
| {non_neg_integer(), non_neg_integer()}
| boolean().
-type token_pair() :: {component(), value()}.
%%---------------------------------------------------------------------------
-type token() :: [] | {integer(), boolean(), _, _, _}.
-spec set_token(token()) -> token() | 'ok'.
set_token([]) ->
erlang:seq_trace(sequential_trace_token,[]);
set_token({Flags,Label,Serial,_From,Lastcnt}) ->
F = decode_flags(Flags),
set_token2([{label,Label},{serial,{Lastcnt, Serial}} | F]).
%% We limit the label type to always be a small integer because erl_interface
%% expects that, the BIF can however "unofficially" handle atoms as well, and
%% atoms can be used if only Erlang nodes are involved
-spec set_token(component(), value()) -> token_pair().
set_token(Type, Val) ->
erlang:seq_trace(Type, Val).
-spec get_token() -> term().
get_token() ->
element(2,process_info(self(),sequential_trace_token)).
-spec get_token(component()) -> token_pair().
get_token(Type) ->
erlang:seq_trace_info(Type).
-spec print(term()) -> 'ok'.
print(Term) ->
erlang:seq_trace_print(Term),
ok.
-spec print(integer(), term()) -> 'ok'.
print(Label, Term) when is_atom(Label) ->
erlang:error(badarg, [Label, Term]);
print(Label, Term) ->
erlang:seq_trace_print(Label, Term),
ok.
-spec reset_trace() -> 'true'.
reset_trace() ->
erlang:system_flag(1, 0).
%% reset_trace(Pid) -> % this might be a useful function too
-type tracer() :: pid() | port() | 'false'.
-spec set_system_tracer(tracer()) -> tracer().
set_system_tracer(Pid) ->
erlang:system_flag(sequential_tracer, Pid).
-spec get_system_tracer() -> tracer().
get_system_tracer() ->
element(2, erlang:system_info(sequential_tracer)).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% internal help functions
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
set_token2([{Type,Val}|T]) ->
erlang:seq_trace(Type, Val),
set_token2(T);
set_token2([]) ->
ok.
decode_flags(Flags) ->
Print = (Flags band ?SEQ_TRACE_PRINT) > 0,
Send = (Flags band ?SEQ_TRACE_SEND) > 0,
Rec = (Flags band ?SEQ_TRACE_RECEIVE) > 0,
Ts = (Flags band ?SEQ_TRACE_TIMESTAMP) > 0,
[{print,Print},{send,Send},{'receive',Rec},{timestamp,Ts}].
