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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License
%% at http://www.mozilla.org/MPL/
%%
%% 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.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developer of the Original Code is GoPivotal, Inc.
%% Copyright (c) 2007-2014 GoPivotal, Inc. All rights reserved.
%%
-module(truncate).
-define(ELLIPSIS_LENGTH, 3).
-record(params, {content, struct, content_dec, struct_dec}).
-export([log_event/2, term/2]).
%% exported for testing
-export([test/0]).
log_event({Type, GL, {Pid, Format, Args}}, Params)
when Type =:= error orelse
Type =:= info_msg orelse
Type =:= warning_msg ->
{Type, GL, {Pid, Format, [term(T, Params) || T <- Args]}};
log_event({Type, GL, {Pid, ReportType, Report}}, Params)
when Type =:= error_report orelse
Type =:= info_report orelse
Type =:= warning_report ->
{Type, GL, {Pid, ReportType, report(Report, Params)}};
log_event(Event, _Params) ->
Event.
report([[Thing]], Params) -> report([Thing], Params);
report(List, Params) when is_list(List) -> [case Item of
{K, V} -> {K, term(V, Params)};
_ -> term(Item, Params)
end || Item <- List];
report(Other, Params) -> term(Other, Params).
term(Thing, {Max, {Content, Struct, ContentDec, StructDec}}) ->
case term_limit(Thing, Max) of
true -> term(Thing, true, #params{content = Content,
struct = Struct,
content_dec = ContentDec,
struct_dec = StructDec});
false -> Thing
end.
term(Bin, _AllowPrintable, #params{content = N})
when (is_binary(Bin) orelse is_bitstring(Bin))
andalso size(Bin) > N - ?ELLIPSIS_LENGTH ->
Suffix = without_ellipsis(N),
<<Head:Suffix/binary, _/bitstring>> = Bin,
<<Head/binary, <<"...">>/binary>>;
term(L, AllowPrintable, #params{struct = N} = Params) when is_list(L) ->
case AllowPrintable andalso io_lib:printable_list(L) of
true -> N2 = without_ellipsis(N),
case length(L) > N2 of
true -> string:left(L, N2) ++ "...";
false -> L
end;
false -> shrink_list(L, Params)
end;
term(T, _AllowPrintable, Params) when is_tuple(T) ->
list_to_tuple(shrink_list(tuple_to_list(T), Params));
term(T, _, _) ->
T.
without_ellipsis(N) -> erlang:max(N - ?ELLIPSIS_LENGTH, 0).
shrink_list(_, #params{struct = N}) when N =< 0 ->
['...'];
shrink_list([], _) ->
[];
shrink_list([H|T], #params{content = Content,
struct = Struct,
content_dec = ContentDec,
struct_dec = StructDec} = Params) ->
[term(H, true, Params#params{content = Content - ContentDec,
struct = Struct - StructDec})
| term(T, false, Params#params{struct = Struct - 1})].
%%----------------------------------------------------------------------------
%% We don't use erts_debug:flat_size/1 because that ignores binary
%% sizes. This is all going to be rather approximate though, these
%% sizes are probably not very "fair" but we are just trying to see if
%% we reach a fairly arbitrary limit anyway though.
term_limit(Thing, Max) ->
case term_size(Thing, Max, erlang:system_info(wordsize)) of
limit_exceeded -> true;
_ -> false
end.
term_size(B, M, _W) when is_bitstring(B) -> lim(M, size(B));
term_size(A, M, W) when is_atom(A) -> lim(M, 2 * W);
term_size(N, M, W) when is_number(N) -> lim(M, 2 * W);
term_size(T, M, W) when is_tuple(T) -> tuple_term_size(
T, M, 1, tuple_size(T), W);
term_size([], M, _W) ->
M;
term_size([H|T], M, W) ->
case term_size(H, M, W) of
limit_exceeded -> limit_exceeded;
M2 -> lim(term_size(T, M2, W), 2 * W)
end;
term_size(X, M, W) ->
lim(M, erts_debug:flat_size(X) * W).
lim(S, T) when is_number(S) andalso S > T -> S - T;
lim(_, _) -> limit_exceeded.
tuple_term_size(_T, limit_exceeded, _I, _S, _W) ->
limit_exceeded;
tuple_term_size(_T, M, I, S, _W) when I > S ->
M;
tuple_term_size(T, M, I, S, W) ->
tuple_term_size(T, lim(term_size(element(I, T), M, W), 2 * W), I + 1, S, W).
%%----------------------------------------------------------------------------
test() ->
test_short_examples_exactly(),
test_term_limit(),
test_large_examples_for_size(),
ok.
test_short_examples_exactly() ->
F = fun (Term, Exp) ->
Exp = term(Term, {1, {10, 10, 5, 5}}),
Term = term(Term, {100000, {10, 10, 5, 5}})
end,
FSmall = fun (Term, Exp) ->
Exp = term(Term, {1, {2, 2, 2, 2}}),
Term = term(Term, {100000, {2, 2, 2, 2}})
end,
F([], []),
F("h", "h"),
F("hello world", "hello w..."),
F([[h,e,l,l,o,' ',w,o,r,l,d]], [[h,e,l,l,o,'...']]),
F([a|b], [a|b]),
F(<<"hello">>, <<"hello">>),
F([<<"hello world">>], [<<"he...">>]),
F(<<1:1>>, <<1:1>>),
F(<<1:81>>, <<0:56, "...">>),
F({{{{a}}},{b},c,d,e,f,g,h,i,j,k}, {{{'...'}},{b},c,d,e,f,g,h,i,j,'...'}),
FSmall({a,30,40,40,40,40}, {a,30,'...'}),
FSmall([a,30,40,40,40,40], [a,30,'...']),
P = spawn(fun() -> receive die -> ok end end),
F([0, 0.0, <<1:1>>, F, P], [0, 0.0, <<1:1>>, F, P]),
P ! die,
R = make_ref(),
F([R], [R]),
ok.
test_term_limit() ->
W = erlang:system_info(wordsize),
S = <<"abc">>,
1 = term_size(S, 4, W),
limit_exceeded = term_size(S, 3, W),
case 100 - term_size([S, S], 100, W) of
22 -> ok; %% 32 bit
38 -> ok %% 64 bit
end,
case 100 - term_size([S, [S]], 100, W) of
30 -> ok; %% ditto
54 -> ok
end,
limit_exceeded = term_size([S, S], 6, W),
ok.
test_large_examples_for_size() ->
%% Real world values
Shrink = fun(Term) -> term(Term, {1, {1000, 100, 50, 5}}) end,
TestSize = fun(Term) ->
true = 5000000 < size(term_to_binary(Term)),
true = 500000 > size(term_to_binary(Shrink(Term)))
end,
TestSize(lists:seq(1, 5000000)),
TestSize(recursive_list(1000, 10)),
TestSize(recursive_list(5000, 20)),
TestSize(gb_sets:from_list([I || I <- lists:seq(1, 1000000)])),
TestSize(gb_trees:from_orddict([{I, I} || I <- lists:seq(1, 1000000)])),
ok.
recursive_list(S, 0) -> lists:seq(1, S);
recursive_list(S, N) -> [recursive_list(S div N, N-1) || _ <- lists:seq(1, S)].
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