Add truc_io:format and use it in the crash logger

src/lager_crash_log.erl

@@ -69,12 +69,11 @@ handle_call(_Call, _From, State) ->
 %% @private
 handle_cast({log, Event}, #state{name=Name, fd=FD, inode=Inode, flap=Flap} = State) ->
     %% TODO these should probably be configurable and have saner defaults
-    FmtMaxBytes = 1024,
-    TermMaxSize = 500,
+    FmtMaxBytes = 6192,
     %% borrowed from riak_err
     {ReportStr, Pid, MsgStr, _ErrorP} = case Event of
         {error, _GL, {Pid1, Fmt, Args}} ->
-            {"ERROR REPORT", Pid1, limited_fmt(Fmt, Args, TermMaxSize, FmtMaxBytes), true};
+            {"ERROR REPORT", Pid1, limited_fmt(Fmt, Args, FmtMaxBytes), true};
         {error_report, _GL, {Pid1, std_error, Rep}} ->
             {"ERROR REPORT", Pid1, limited_str(Rep, FmtMaxBytes), true};
         {error_report, _GL, Other} ->
@@ -127,7 +126,7 @@ code_change(_OldVsn, State, _Extra) ->
 
 %% ===== Begin code lifted from riak_err =====
 
--spec limited_fmt(string(), list(), integer(), integer()) -> iolist().
+-spec limited_fmt(string(), list(), integer()) -> iolist().
 %% @doc Format Fmt and Args similar to what io_lib:format/2 does but with 
 %%      limits on how large the formatted string may be.
 %%
@@ -135,19 +134,8 @@ code_change(_OldVsn, State, _Extra) ->
 %% formatting is done by trunc_io:print/2, where FmtMaxBytes is used
 %% to limit the formatted string's size.
 
-limited_fmt(Fmt, Args, TermMaxSize, FmtMaxBytes) ->
-    TermSize = erts_debug:flat_size(Args),
-    if TermSize > TermMaxSize ->
-            ["Oversize args for format \"", Fmt, "\": \n",
-                [
-                    begin
-                            {Str, _} = trunc_io:print(lists:nth(N, Args), FmtMaxBytes),
-                            ["  arg", integer_to_list(N), ": ", Str, "\n"]
-                    end || N <- lists:seq(1, length(Args))
-                ]];
-        true ->
-            io_lib:format(Fmt, Args)
-    end.
+limited_fmt(Fmt, Args, FmtMaxBytes) ->
+    trunc_io:format(Fmt, Args, FmtMaxBytes).
 
 limited_str(Term, FmtMaxBytes) ->
     {Str, _} = trunc_io:print(Term, FmtMaxBytes),

src/trunc_io.erl

@@ -29,10 +29,90 @@
 -module(trunc_io).
 -author('matthias@corelatus.se').
 %% And thanks to Chris Newcombe for a bug fix 
--export([print/2, fprint/2, safe/2]).               % interface functions
+-export([format/3, print/2, fprint/2, safe/2]).               % interface functions
 -export([perf/0, perf/3, perf1/0, test/0, test/2]). % testing functions
 -version("$Id: trunc_io.erl,v 1.11 2009-02-23 12:01:06 matthias Exp $").
 
+format(String, Args, Max) ->
+    Parts = re:split(String,
+        "(~(?:-??\\d+\\.|\\*\\.|)(?:-??\d+\\.|\\*\\.|)(?:-??\\d+|\\*|)(?:t|)(?:[cfegswpWPBX#bx+ni]))",
+        [{return, list}, trim]),
+    Maxlen = Max - length(String),
+    format(Parts, Args, Maxlen, [], []).
+
+format([], _Args, _Max, Acc, ArgAcc) ->
+    io_lib:format(lists:flatten(lists:reverse(Acc)), lists:reverse(ArgAcc));
+format([[] | T], Args, Max, Acc, ArgAcc) ->
+    % discard the null list generated by split
+    format(T, Args, Max, Acc, ArgAcc);
+format(["~n" | T], Args, Max, Acc, ArgAcc) ->
+    % ignore newlines for the purposes of argument indexing
+    format(T, Args, Max+1, ["~n" | Acc], ArgAcc);
+format(["~i" | T], [AH | AT], Max, Acc, ArgAcc) ->
+    % ~i means ignore this argument, but we'll just pass it through
+    format(T, AT, Max+2, ["~i" | Acc], [AH | ArgAcc]);
+format([[$~|H]| T], [AH1, AH2 | AT], Max, Acc, ArgAcc) when H == "W"; H == "P"; H == "X" ->
+    % these crazy ones consume TWO arguments, just pass them through
+    % because W and P implicitly limit size so we trust the user knows
+    % what they're doing. Unfortunately we can't change Max at all because
+    % depth based limits are not of known length.
+    format(T, AT, Max, [[$~ | H] | Acc], [AH2, AH1 | ArgAcc]);
+format([[$~|H]| T], [AH | AT], Max, Acc, ArgAcc) when length(H) == 1 ->
+    % single character format specifier, relatively simple
+    case H of
+        _ when H == "p"; H == "w"; H == "s" ->
+            %okay, these are prime candidates for rewriting
+            {String, Length} = case print(AH, Max) of
+                {_Res, Max} when AT /= [] ->
+                    % this isn't the last argument, but it consumed all available space, give it half instead
+                    print(AH, Max div 2);
+                {Res, Len} ->
+                    {Res, Len}
+            end,
+            {Value, RealLen} = case H of
+                "s" ->
+                    % strip off the doublequotes
+                    {string:substr(String, 2, length(String) -2), Length -2};
+                _ ->
+                    {String, Length}
+            end,
+            format(T, AT, Max + 2 - RealLen, ["~s" | Acc], [Value | ArgAcc]);
+        _ ->
+            % whatever, just pass them on through
+            format(T, AT, Max, [[$~ | H], Acc], [AH | ArgAcc])
+    end;
+format([[$~|H]| T], [AH | AT], Max, Acc, ArgAcc) ->
+    %% TODO
+    % complicated format specifier, gonna have to parse it..
+    case re:run(H, "^(?:-??(\\d+|\\*)\\.|)(?:-??(\\d+|\\*)\\.|)(-??\\d+|\\*|)(t|)([cfegswpWPBX#bx+ni])$", [{capture, all_but_first, list}]) of
+        {match, [_F, _P, _Pad, _Mod, C]} when C == "p"; C=="w"; C=="s" ->
+            %okay, these are prime candidates for rewriting
+            {String, Length} = case print(AH, Max) of
+                {_Res, Max} when AT /= [] ->
+                    % this isn't the last argument, but it consumed all available space, give it half instead
+                    print(AH, Max div 2);
+                {Res, Len} ->
+                    {Res, Len}
+            end,
+            {Value, RealLen} = case H of
+                "s" ->
+                    % strip off the doublequotes
+                    {string:substr(String, 2, length(String) -2), Length -2};
+                _ ->
+                    {String, Length}
+            end,
+            format(T, AT, Max + length(H) + 1 - RealLen, ["~s" | Acc], [Value | ArgAcc]);
+        {match, [_F, _P, _Pad, _Mod, C]} when C == "P"; C=="W" ->
+            [AH2 | AT2] = AT,
+            format(T, AT2, Max, [[$~|H]|Acc], [AH2, AH |ArgAcc]);
+        {match, _} ->
+            format(T, AT, Max, [H | Acc], [AH|ArgAcc]);
+        nomatch ->
+            io:format("unable to match format pattern ~~~p~n", [H]),
+            format(T, AT, Max, [H | Acc], [AH|ArgAcc])
+    end;
+format([H | T], Args, Max, Acc, ArgAcc) ->
+    format(T, Args, Max, [H | Acc], ArgAcc).
 
 %% @doc Returns an flattened list containing the ASCII representation of the given
 %% term.
@@ -79,7 +159,7 @@ print(<<>>, _Max) ->
 print(Binary, Max) when is_binary(Binary) ->
     B = binary_to_list(Binary, 1, lists:min([Max, size(Binary)])),
     {L, Len} = alist_start(B, Max-4),
-    {["<<", L, ">>"], Len};
+    {["<<", L, ">>"], Len+4};
 
 print(Float, _Max) when is_float(Float) ->
     L = float_to_list(Float),
@@ -146,7 +226,7 @@ alist_start([], _) -> {"[]", 2};
 alist_start(_, Max) when Max < 4 -> {"...", 3};
 alist_start([H|T], Max) when H >= 16#20, H =< 16#7e ->  % definitely printable
     {L, Len} = alist([H|T], Max-1),
-    {[$\"|L], Len + 1};
+    {[$"|L], Len + 1};
 alist_start([H|T], Max) when H == 9; H == 10; H == 13 ->   % show as space
     {L, Len} = alist(T, Max-1),
     {[$ |L], Len + 1};
@@ -164,7 +244,7 @@ alist([H|T], Max) when H == 9; H == 10; H == 13 ->   % show as space
     {[$ |L], Len + 1};
 alist(L, Max) ->
     {R, Len} = list_body(L, Max-3),
-    {[$\", $[, R, $]], Len + 3}.
+    {[$", $[, R, $]], Len + 3}.
 
 
 %%--------------------