diff options
| -rw-r--r-- | lib/stdlib/src/io_lib.erl | 115 | ||||
| -rw-r--r-- | lib/stdlib/test/io_SUITE.erl | 59 |
2 files changed, 172 insertions, 2 deletions
diff --git a/lib/stdlib/src/io_lib.erl b/lib/stdlib/src/io_lib.erl index 5ed2f4d888..9d447418f8 100644 --- a/lib/stdlib/src/io_lib.erl +++ b/lib/stdlib/src/io_lib.erl @@ -84,6 +84,8 @@ -export([write_unicode_string/1, write_unicode_char/1, deep_unicode_char_list/1]). +-export([limit_term/2]). + -export_type([chars/0, latin1_string/0, continuation/0, fread_error/0, fread_item/0, format_spec/0]). @@ -911,3 +913,116 @@ binrev(L) -> binrev(L, T) -> list_to_binary(lists:reverse(L, T)). + +-spec limit_term(term(), non_neg_integer()) -> term(). + +%% The intention is to mimic the depth limitation of io_lib:write() +%% and io_lib_pretty:print(). The leaves ('...') should never be +%% seen when printed with the same depth. Bitstrings are never +%% truncated, which is OK as long as they are not sent to other nodes. +limit_term(Term, Depth) -> + try test_limit(Term, Depth) of + ok -> Term + catch + throw:limit -> + limit(Term, Depth) + end. + +limit(_, 0) -> '...'; +limit([H|T]=L, D) -> + if + D =:= 1 -> '...'; + true -> + case printable_list(L) of + true -> L; + false -> + [limit(H, D-1)|limit_tail(T, D-1)] + end + end; +limit(Term, D) when is_map(Term) -> + limit_map(Term, D); +limit({}=T, _D) -> T; +limit(T, D) when is_tuple(T) -> + if + D =:= 1 -> '...'; + true -> + list_to_tuple([limit(element(1, T), D-1)| + limit_tail(tl(tuple_to_list(T)), D-1)]) + end; +limit(<<_/bitstring>>=Term, D) -> limit_bitstring(Term, D); +limit(Term, _D) -> Term. + +limit_tail([], _D) -> []; +limit_tail(_, 1) -> ['...']; +limit_tail([H|T], D) -> + [limit(H, D-1)|limit_tail(T, D-1)]; +limit_tail(Other, D) -> + limit(Other, D-1). + +%% Cannot limit maps properly since there is no guarantee that +%% maps:from_list() creates a map with the same internal ordering of +%% the selected associations as in Map. +limit_map(Map, D) -> + maps:from_list(erts_internal:maps_to_list(Map, D)). +%% maps:from_list(limit_map_body(erts_internal:maps_to_list(Map, D), D)). + +%% limit_map_body(_, 0) -> [{'...', '...'}]; +%% limit_map_body([], _) -> []; +%% limit_map_body([{K,V}], D) -> [limit_map_assoc(K, V, D)]; +%% limit_map_body([{K,V}|KVs], D) -> +%% [limit_map_assoc(K, V, D) | limit_map_body(KVs, D-1)]. + +%% limit_map_assoc(K, V, D) -> +%% {limit(K, D-1), limit(V, D-1)}. + +limit_bitstring(B, _D) -> B. %% Keeps all printable binaries. + +test_limit(_, 0) -> throw(limit); +test_limit([H|T]=L, D) when is_integer(D) -> + if + D =:= 1 -> throw(limit); + true -> + case printable_list(L) of + true -> ok; + false -> + test_limit(H, D-1), + test_limit_tail(T, D-1) + end + end; +test_limit(Term, D) when is_map(Term) -> + test_limit_map(Term, D); +test_limit({}, _D) -> ok; +test_limit(T, D) when is_tuple(T) -> + test_limit_tuple(T, 1, tuple_size(T), D); +test_limit(<<_/bitstring>>=Term, D) -> test_limit_bitstring(Term, D); +test_limit(_Term, _D) -> ok. + +test_limit_tail([], _D) -> ok; +test_limit_tail(_, 1) -> throw(limit); +test_limit_tail([H|T], D) -> + test_limit(H, D-1), + test_limit_tail(T, D-1); +test_limit_tail(Other, D) -> + test_limit(Other, D-1). + +test_limit_tuple(_T, I, Sz, _D) when I > Sz -> ok; +test_limit_tuple(_, _, _, 1) -> throw(limit); +test_limit_tuple(T, I, Sz, D) -> + test_limit(element(I, T), D-1), + test_limit_tuple(T, I+1, Sz, D-1). + +test_limit_map(_Map, _D) -> ok. +%% test_limit_map_body(erts_internal:maps_to_list(Map, D), D). + +%% test_limit_map_body(_, 0) -> throw(limit); +%% test_limit_map_body([], _) -> ok; +%% test_limit_map_body([{K,V}], D) -> test_limit_map_assoc(K, V, D); +%% test_limit_map_body([{K,V}|KVs], D) -> +%% test_limit_map_assoc(K, V, D), +%% test_limit_map_body(KVs, D-1). + +%% test_limit_map_assoc(K, V, D) -> +%% test_limit(K, D-1), +%% test_limit(V, D-1). + +test_limit_bitstring(_, _) -> ok. diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl index ef3f0be5d7..e2c73371cd 100644 --- a/lib/stdlib/test/io_SUITE.erl +++ b/lib/stdlib/test/io_SUITE.erl @@ -31,7 +31,7 @@ otp_10836/1, io_lib_width_too_small/1, io_with_huge_message_queue/1, format_string/1, maps/1, coverage/1, otp_14178_unicode_atoms/1, otp_14175/1, - otp_14285/1]). + otp_14285/1, limit_term/1]). -export([pretty/2]). @@ -63,7 +63,7 @@ all() -> io_lib_print_binary_depth_one, otp_10302, otp_10755, otp_10836, io_lib_width_too_small, io_with_huge_message_queue, format_string, maps, coverage, otp_14178_unicode_atoms, otp_14175, - otp_14285]. + otp_14285, limit_term]. %% Error cases for output. error_1(Config) when is_list(Config) -> @@ -2373,3 +2373,58 @@ otp_14285(_Config) -> latin1_fmt(Fmt, Args) -> L = fmt(Fmt, Args), true = lists:all(fun is_latin1/1, L). + +limit_term(_Config) -> + {_, 2} = limt([a,b,c], 2), + {_, 2} = limt([a,b,c], 3), + {_, 2} = limt([a,b|c], 2), + {_, 2} = limt([a,b|c], 3), + {_, 2} = limt({a,b,c,[d,e]}, 2), + {_, 2} = limt({a,b,c,[d,e]}, 3), + {_, 2} = limt({a,b,c,[d,e]}, 4), + {_, 1} = limt(<<"foo">>, 18), + ok = blimt(<<"123456789012345678901234567890">>), + {_, 1} = limt(<<7:3>>, 2), + {_, 1} = limt(<<7:21>>, 2), + {_, 1} = limt([], 2), + {_, 1} = limt({}, 2), + {_, 1} = limt(#{}, 2), + {_, 1} = limt(#{[] => {}}, 2), + {_, 1} = limt(#{[] => {}}, 3), + T = #{[] => {},[a] => [b]}, + {_, 1} = limt(T, 2), + {_, 1} = limt(T, 3), + {_, 1} = limt(T, 4), + ok. + +blimt(Binary) -> + blimt(Binary, byte_size(Binary)). + +blimt(_B, 1) -> ok; +blimt(B, D) -> + {_, 1} = limt(B, D), + blimt(B, D - 1). + +limt(Term, Depth) when is_integer(Depth) -> + T1 = io_lib:limit_term(Term, Depth), + S = form(Term, Depth), + S1 = form(T1, Depth), + OK1 = S1 =:= S, + + T2 = io_lib:limit_term(Term, Depth+1), + S2 = form(T2, Depth), + OK2 = S2 =:= S, + + T3 = io_lib:limit_term(Term, Depth-1), + S3 = form(T3, Depth), + OK3 = S3 =/= S, + + R = case {OK1, OK2, OK3} of + {true, true, true} -> 2; + {true, true, false} -> 1; + _ -> 0 + end, + {{S, S1, S2}, R}. + +form(Term, Depth) -> + lists:flatten(io_lib:format("~W", [Term, Depth])). |