%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2012. 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(lib). -export([flush_receive/0, error_message/2, progname/0, nonl/1, send/2, sendw/2, eval_str/1]). -export([format_exception/6, format_stacktrace/4, format_call/4, format_fun/1]). -spec flush_receive() -> 'ok'. flush_receive() -> receive _Any -> flush_receive() after 0 -> ok end. %% %% Functions for doing standard system format i/o. %% -spec error_message(Format, Args) -> 'ok' when Format :: io:format(), Args :: [term()]. error_message(Format, Args) -> io:format(<<"** ~s **\n">>, [io_lib:format(Format, Args)]). %% Return the name of the script that starts (this) erlang %% -spec progname() -> atom(). progname() -> case init:get_argument(progname) of {ok, [[Prog]]} -> list_to_atom(Prog); _Other -> no_prog_name end. -spec nonl(String1) -> String2 when String1 :: string(), String2 :: string(). nonl([10]) -> []; nonl([]) -> []; nonl([H|T]) -> [H|nonl(T)]. -spec send(To, Msg) -> Msg when To :: pid() | atom() | {atom(), node()}, Msg :: term(). send(To, Msg) -> To ! Msg. -spec sendw(To, Msg) -> Msg when To :: pid() | atom() | {atom(), node()}, Msg :: term(). sendw(To, Msg) -> To ! {self(), Msg}, receive Reply -> Reply end. %% eval_str(InStr) -> {ok, OutStr} | {error, ErrStr'} %% InStr must represent a body -define(result(F,D), lists:flatten(io_lib:format(F, D))). -spec eval_str(string() | binary()) -> {'ok', string()} | {'error', string()}. eval_str(Str) when is_list(Str) -> case erl_scan:tokens([], Str, 0) of {more, _} -> {error, "Incomplete form (missing .<cr>)??"}; {done, {ok, Toks, _}, Rest} -> case all_white(Rest) of true -> case erl_parse:parse_exprs(Toks) of {ok, Exprs} -> case catch erl_eval:exprs(Exprs, erl_eval:new_bindings()) of {value, Val, _} -> {ok, Val}; Other -> {error, ?result("*** eval: ~p", [Other])} end; {error, {_Line, Mod, Args}} -> Msg = ?result("*** ~s",[Mod:format_error(Args)]), {error, Msg} end; false -> {error, ?result("Non-white space found after " "end-of-form :~s", [Rest])} end end; eval_str(Bin) when is_binary(Bin) -> eval_str(binary_to_list(Bin)). all_white([$\s|T]) -> all_white(T); all_white([$\n|T]) -> all_white(T); all_white([$\t|T]) -> all_white(T); all_white([]) -> true; all_white(_) -> false. %%% Formatting of exceptions, mfa:s and funs. %% -> iolist() (no \n at end) %% I is the current column, starting from 1 (it will be used %% as indentation whenever newline has been inserted); %% Class, Reason and StackTrace are the exception; %% FormatFun = fun(Term, I) -> iolist() formats terms; %% StackFun = fun(Mod, Fun, Arity) -> bool() is used for trimming the %% end of the stack (typically calls to erl_eval are skipped). format_exception(I, Class, Reason, StackTrace, StackFun, FormatFun) when is_integer(I), I >= 1, is_function(StackFun, 3), is_function(FormatFun, 2) -> S = n_spaces(I-1), {Term,Trace1,Trace} = analyze_exception(Class, Reason, StackTrace), Expl0 = explain_reason(Term, Class, Trace1, FormatFun, S), Expl = io_lib:fwrite(<<"~s~s">>, [exited(Class), Expl0]), case format_stacktrace1(S, Trace, FormatFun, StackFun) of [] -> Expl; Stack -> [Expl, $\n, Stack] end. %% -> iolist() (no \n at end) format_stacktrace(I, StackTrace, StackFun, FormatFun) when is_integer(I), I >= 1, is_function(StackFun, 3), is_function(FormatFun, 2) -> S = n_spaces(I-1), format_stacktrace1(S, StackTrace, FormatFun, StackFun). %% -> iolist() (no \n at end) format_call(I, ForMForFun, As, FormatFun) when is_integer(I), I >= 1, is_list(As), is_function(FormatFun, 2) -> format_call("", n_spaces(I-1), ForMForFun, As, FormatFun). %% -> iolist() (no \n at end) format_fun(Fun) when is_function(Fun) -> {module, M} = erlang:fun_info(Fun, module), {name, F} = erlang:fun_info(Fun, name), {arity, A} = erlang:fun_info(Fun, arity), case erlang:fun_info(Fun, type) of {type, local} when F =:= "" -> io_lib:fwrite(<<"~w">>, [Fun]); {type, local} when M =:= erl_eval -> io_lib:fwrite(<<"interpreted function with arity ~w">>, [A]); {type, local} -> mfa_to_string(M, F, A); {type, external} -> mfa_to_string(M, F, A) end. analyze_exception(error, Term, Stack) -> case {is_stacktrace(Stack), Stack, Term} of {true, [{_,_,As,_}=MFAL|MFAs], function_clause} when is_list(As) -> {Term,[MFAL],MFAs}; {true, [{shell,F,A,_}], function_clause} when is_integer(A) -> {Term, [{F,A}], []}; {true, [{_,_,_,_}=MFAL|MFAs], undef} -> {Term,[MFAL],MFAs}; {true, _, _} -> {Term,[],Stack}; {false, _, _} -> {{Term,Stack},[],[]} end; analyze_exception(_Class, Term, Stack) -> case is_stacktrace(Stack) of true -> {Term,[],Stack}; false -> {{Term,Stack},[],[]} end. is_stacktrace([]) -> true; is_stacktrace([{M,F,A,I}|Fs]) when is_atom(M), is_atom(F), is_integer(A), is_list(I) -> is_stacktrace(Fs); is_stacktrace([{M,F,As,I}|Fs]) when is_atom(M), is_atom(F), length(As) >= 0, is_list(I) -> is_stacktrace(Fs); is_stacktrace(_) -> false. %% ERTS exit codes (some of them are also returned by erl_eval): explain_reason(badarg, error, [], _PF, _S) -> <<"bad argument">>; explain_reason({badarg,V}, error=Cl, [], PF, S) -> % orelse, andalso format_value(V, <<"bad argument: ">>, Cl, PF, S); explain_reason(badarith, error, [], _PF, _S) -> <<"an error occurred when evaluating an arithmetic expression">>; explain_reason({badarity,{Fun,As}}, error, [], _PF, _S) when is_function(Fun) -> %% Only the arity is displayed, not the arguments As. io_lib:fwrite(<<"~s called with ~s">>, [format_fun(Fun), argss(length(As))]); explain_reason({badfun,Term}, error=Cl, [], PF, S) -> format_value(Term, <<"bad function ">>, Cl, PF, S); explain_reason({badmatch,Term}, error=Cl, [], PF, S) -> format_value(Term, <<"no match of right hand side value ">>, Cl, PF, S); explain_reason({case_clause,V}, error=Cl, [], PF, S) -> %% "there is no case clause with a true guard sequence and a %% pattern matching..." format_value(V, <<"no case clause matching ">>, Cl, PF, S); explain_reason(function_clause, error, [{F,A}], _PF, _S) -> %% Shell commands FAs = io_lib:fwrite(<<"~w/~w">>, [F, A]), [<<"no function clause matching call to ">> | FAs]; explain_reason(function_clause, error=Cl, [{M,F,As,Loc}], PF, S) -> Str = <<"no function clause matching ">>, [format_errstr_call(Str, Cl, {M,F}, As, PF, S),$\s|location(Loc)]; explain_reason(if_clause, error, [], _PF, _S) -> <<"no true branch found when evaluating an if expression">>; explain_reason(noproc, error, [], _PF, _S) -> <<"no such process or port">>; explain_reason(notalive, error, [], _PF, _S) -> <<"the node cannot be part of a distributed system">>; explain_reason(system_limit, error, [], _PF, _S) -> <<"a system limit has been reached">>; explain_reason(timeout_value, error, [], _PF, _S) -> <<"bad receive timeout value">>; explain_reason({try_clause,V}, error=Cl, [], PF, S) -> %% "there is no try clause with a true guard sequence and a %% pattern matching..." format_value(V, <<"no try clause matching ">>, Cl, PF, S); explain_reason(undef, error, [{M,F,A,_}], _PF, _S) -> %% Only the arity is displayed, not the arguments, if there are any. io_lib:fwrite(<<"undefined function ~s">>, [mfa_to_string(M, F, n_args(A))]); explain_reason({shell_undef,F,A,_}, error, [], _PF, _S) -> %% Give nicer reports for undefined shell functions %% (but not when the user actively calls shell_default:F(...)). io_lib:fwrite(<<"undefined shell command ~s/~w">>, [F, n_args(A)]); %% Exit codes returned by erl_eval only: explain_reason({argument_limit,_Fun}, error, [], _PF, _S) -> io_lib:fwrite(<<"limit of number of arguments to interpreted function" " exceeded">>, []); explain_reason({bad_filter,V}, error=Cl, [], PF, S) -> format_value(V, <<"bad filter ">>, Cl, PF, S); explain_reason({bad_generator,V}, error=Cl, [], PF, S) -> format_value(V, <<"bad generator ">>, Cl, PF, S); explain_reason({unbound,V}, error, [], _PF, _S) -> io_lib:fwrite(<<"variable ~w is unbound">>, [V]); %% Exit codes local to the shell module (restricted shell): explain_reason({restricted_shell_bad_return, V}, exit=Cl, [], PF, S) -> Str = <<"restricted shell module returned bad value ">>, format_value(V, Str, Cl, PF, S); explain_reason({restricted_shell_disallowed,{ForMF,As}}, exit=Cl, [], PF, S) -> %% ForMF can be a fun, but not a shell fun. Str = <<"restricted shell does not allow ">>, format_errstr_call(Str, Cl, ForMF, As, PF, S); explain_reason(restricted_shell_started, exit, [], _PF, _S) -> <<"restricted shell starts now">>; explain_reason(restricted_shell_stopped, exit, [], _PF, _S) -> <<"restricted shell stopped">>; %% Other exit code: explain_reason(Reason, Class, [], PF, S) -> PF(Reason, (iolist_size(S)+1) + exited_size(Class)). n_args(A) when is_integer(A) -> A; n_args(As) when is_list(As) -> length(As). argss(0) -> <<"no arguments">>; argss(1) -> <<"one argument">>; argss(2) -> <<"two arguments">>; argss(I) -> io_lib:fwrite(<<"~w arguments">>, [I]). format_stacktrace1(S0, Stack0, PF, SF) -> Stack1 = lists:dropwhile(fun({M,F,A,_}) -> SF(M, F, A) end, lists:reverse(Stack0)), S = [" " | S0], Stack = lists:reverse(Stack1), format_stacktrace2(S, Stack, 1, PF). format_stacktrace2(S, [{M,F,A,L}|Fs], N, PF) when is_integer(A) -> [io_lib:fwrite(<<"~s~s ~s ~s">>, [sep(N, S), origin(N, M, F, A), mfa_to_string(M, F, A), location(L)]) | format_stacktrace2(S, Fs, N + 1, PF)]; format_stacktrace2(S, [{M,F,As,_}|Fs], N, PF) when is_list(As) -> A = length(As), CalledAs = [S,<<" called as ">>], C = format_call("", CalledAs, {M,F}, As, PF), [io_lib:fwrite(<<"~s~s ~s\n~s~s">>, [sep(N, S), origin(N, M, F, A), mfa_to_string(M, F, A), CalledAs, C]) | format_stacktrace2(S, Fs, N + 1, PF)]; format_stacktrace2(_S, [], _N, _PF) -> "". location(L) -> File = proplists:get_value(file, L), Line = proplists:get_value(line, L), if File =/= undefined, Line =/= undefined -> io_lib:format("(~s, line ~w)", [File, Line]); true -> "" end. sep(1, S) -> S; sep(_, S) -> [$\n | S]. origin(1, M, F, A) -> case is_op({M, F}, n_args(A)) of {yes, F} -> <<"in operator ">>; no -> <<"in function ">> end; origin(_N, _M, _F, _A) -> <<"in call from">>. format_errstr_call(ErrStr, Class, ForMForFun, As, PF, Pre0) -> Pre1 = [Pre0 | n_spaces(exited_size(Class))], format_call(ErrStr, Pre1, ForMForFun, As, PF). format_call(ErrStr, Pre1, ForMForFun, As, PF) -> Arity = length(As), [ErrStr | case is_op(ForMForFun, Arity) of {yes,Op} -> format_op(ErrStr, Pre1, Op, As, PF); no -> MFs = mf_to_string(ForMForFun, Arity), I1 = iolist_size([Pre1,ErrStr|MFs]), S1 = pp_arguments(PF, As, I1), S2 = pp_arguments(PF, As, iolist_size([Pre1|MFs])), Long = count_nl(pp_arguments(PF, [a2345,b2345], I1)) > 0, case Long or (count_nl(S2) < count_nl(S1)) of true -> [$\n, Pre1, MFs, S2]; false -> [MFs, S1] end end]. format_op(ErrStr, Pre, Op, [A1], PF) -> OpS = io_lib:fwrite(<<"~s ">>, [Op]), I1 = iolist_size([ErrStr,Pre,OpS]), [OpS | PF(A1, I1+1)]; format_op(ErrStr, Pre, Op, [A1, A2], PF) -> I1 = iolist_size([ErrStr,Pre]), S1 = PF(A1, I1+1), S2 = PF(A2, I1+1), OpS = atom_to_list(Op), Pre1 = [$\n | n_spaces(I1)], case count_nl(S1) > 0 of true -> [S1,Pre1,OpS,Pre1|S2]; false -> OpS2 = io_lib:fwrite(<<" ~s ">>, [Op]), S2_2 = PF(A2, iolist_size([ErrStr,Pre,S1|OpS2])+1), case count_nl(S2) < count_nl(S2_2) of true -> [S1,Pre1,OpS,Pre1|S2]; false -> [S1,OpS2|S2_2] end end. pp_arguments(PF, As, I) -> case {As, io_lib:printable_list(As)} of {[Int | T], true} -> L = integer_to_list(Int), Ll = length(L), A = list_to_atom(lists:duplicate(Ll, $a)), S0 = binary_to_list(iolist_to_binary(PF([A | T], I+1))), brackets_to_parens([$[,L,string:sub_string(S0, 2+Ll)]); _ -> brackets_to_parens(PF(As, I+1)) end. brackets_to_parens(S) -> B = iolist_to_binary(S), Sz = byte_size(B) - 2, <<$[,R:Sz/binary,$]>> = B, [$(,R,$)]. mfa_to_string(M, F, A) -> io_lib:fwrite(<<"~s/~w">>, [mf_to_string({M, F}, A), A]). mf_to_string({M, F}, A) -> case erl_internal:bif(M, F, A) of true -> io_lib:fwrite(<<"~w">>, [F]); false -> case is_op({M, F}, A) of {yes, '/'} -> io_lib:fwrite(<<"~w">>, [F]); {yes, F} -> atom_to_list(F); no -> io_lib:fwrite(<<"~w:~w">>, [M, F]) end end; mf_to_string(Fun, _A) when is_function(Fun) -> format_fun(Fun); mf_to_string(F, _A) -> io_lib:fwrite(<<"~w">>, [F]). format_value(V, ErrStr, Class, PF, S) -> Pre1Sz = exited_size(Class), S1 = PF(V, Pre1Sz + iolist_size([S, ErrStr])+1), [ErrStr | case count_nl(S1) of N1 when N1 > 1 -> S2 = PF(V, iolist_size(S) + 1 + Pre1Sz), case count_nl(S2) < N1 of true -> [$\n, S, n_spaces(Pre1Sz) | S2]; false -> S1 end; _ -> S1 end]. %% Handles deep lists, but not all iolists. count_nl([E | Es]) -> count_nl(E) + count_nl(Es); count_nl($\n) -> 1; count_nl(Bin) when is_binary(Bin) -> count_nl(binary_to_list(Bin)); count_nl(_) -> 0. n_spaces(N) -> lists:duplicate(N, $\s). is_op(ForMForFun, A) -> try {erlang,F} = ForMForFun, _ = erl_internal:op_type(F, A), {yes,F} catch error:_ -> no end. exited_size(Class) -> iolist_size(exited(Class)). exited(error) -> <<"exception error: ">>; exited(exit) -> <<"exception exit: ">>; exited(throw) -> <<"exception throw: ">>.