util/debug.lua

   1 -- Variables ending with these names will not
   2 -- have their values printed ('password' includes
   3 -- 'new_password', etc.)
   4 local censored_names = {
   5         password = true;
   6         passwd = true;
   7         pass = true;
   8         pwd = true;
   9 };
  10 local optimal_line_length = 65;
  11
  12 local termcolours = require "util.termcolours";
  13 local getstring = termcolours.getstring;
  14 local styles;
  15 do
  16         _ = termcolours.getstyle;
  17         styles = {
  18                 boundary_padding = _("bright");
  19                 filename         = _("bright", "blue");
  20                 level_num        = _("green");
  21                 funcname         = _("yellow");
  22                 location         = _("yellow");
  23         };
  24 end
  25 module("debugx", package.seeall);
  26
  27 function get_locals_table(thread, level)
  28         local locals = {};
  29         for local_num = 1, math.huge do
  30                 local name, value;
  31                 if thread then
  32                         name, value = debug.getlocal(thread, level, local_num);
  33                 else
  34                         name, value = debug.getlocal(level+1, local_num);
  35                 end
  36                 if not name then break; end
  37                 table.insert(locals, { name = name, value = value });
  38         end
  39         return locals;
  40 end
  41
  42 function get_upvalues_table(func)
  43         local upvalues = {};
  44         if func then
  45                 for upvalue_num = 1, math.huge do
  46                         local name, value = debug.getupvalue(func, upvalue_num);
  47                         if not name then break; end
  48                         table.insert(upvalues, { name = name, value = value });
  49                 end
  50         end
  51         return upvalues;
  52 end
  53
  54 function string_from_var_table(var_table, max_line_len, indent_str)
  55         local var_string = {};
  56         local col_pos = 0;
  57         max_line_len = max_line_len or math.huge;
  58         indent_str = "\n"..(indent_str or "");
  59         for _, var in ipairs(var_table) do
  60                 local name, value = var.name, var.value;
  61                 if name:sub(1,1) ~= "(" then
  62                         if type(value) == "string" then
  63                                 if censored_names[name:match("%a+$")] then
  64                                         value = "<hidden>";
  65                                 else
  66                                         value = ("%q"):format(value);
  67                                 end
  68                         else
  69                                 value = tostring(value);
  70                         end
  71                         if #value > max_line_len then
  72                                 value = value:sub(1, max_line_len-3).."…";
  73                         end
  74                         local str = ("%s = %s"):format(name, tostring(value));
  75                         col_pos = col_pos + #str;
  76                         if col_pos > max_line_len then
  77                                 table.insert(var_string, indent_str);
  78                                 col_pos = 0;
  79                         end
  80                         table.insert(var_string, str);
  81                 end
  82         end
  83         if #var_string == 0 then
  84                 return nil;
  85         else
  86                 return "{ "..table.concat(var_string, ", "):gsub(indent_str..", ", indent_str).." }";
  87         end
  88 end
  89
  90 function get_traceback_table(thread, start_level)
  91         local levels = {};
  92         for level = start_level, math.huge do
  93                 local info;
  94                 if thread then
  95                         info = debug.getinfo(thread, level);
  96                 else
  97                         info = debug.getinfo(level+1);
  98                 end
  99                 if not info then break; end
 100
 101                 levels[(level-start_level)+1] = {
 102                         level = level;
 103                         info = info;
 104                         locals = get_locals_table(thread, level+(thread and 0 or 1));
 105                         upvalues = get_upvalues_table(info.func);
 106                 };
 107         end
 108         return levels;
 109 end
 110
 111 function traceback(...)
 112         local ok, ret = pcall(_traceback, ...);
 113         if not ok then
 114                 return "Error in error handling: "..ret;
 115         end
 116         return ret;
 117 end
 118
 119 local function build_source_boundary_marker(last_source_desc)
 120         local padding = string.rep("-", math.floor(((optimal_line_length - 6) - #last_source_desc)/2));
 121         return getstring(styles.boundary_padding, "v"..padding).." "..getstring(styles.filename, last_source_desc).." "..getstring(styles.boundary_padding, padding..(#last_source_desc%2==0 and "-v" or "v "));
 122 end
 123
 124 function _traceback(thread, message, level)
 125
 126         -- Lua manual says: debug.traceback ([thread,] [message [, level]])
 127         -- I fathom this to mean one of:
 128         -- ()
 129         -- (thread)
 130         -- (message, level)
 131         -- (thread, message, level)
 132
 133         if thread == nil then -- Defaults
 134                 thread, message, level = coroutine.running(), message, level;
 135         elseif type(thread) == "string" then
 136                 thread, message, level = coroutine.running(), thread, message;
 137         elseif type(thread) ~= "thread" then
 138                 return nil; -- debug.traceback() does this
 139         end
 140
 141         level = level or 0;
 142
 143         message = message and (message.."\n") or "";
 144
 145         -- +3 counts for this function, and the pcall() and wrapper above us, the +1... I don't know.
 146         local levels = get_traceback_table(thread, level+(thread == nil and 4 or 0));
 147
 148         local last_source_desc;
 149
 150         local lines = {};
 151         for nlevel, level in ipairs(levels) do
 152                 local info = level.info;
 153                 local line = "...";
 154                 local func_type = info.namewhat.." ";
 155                 local source_desc = (info.short_src == "[C]" and "C code") or info.short_src or "Unknown";
 156                 if func_type == " " then func_type = ""; end;
 157                 if info.short_src == "[C]" then
 158                         line = "[ C ] "..func_type.."C function "..getstring(styles.location, (info.name and ("%q"):format(info.name) or "(unknown name)"));
 159                 elseif info.what == "main" then
 160                         line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline);
 161                 else
 162                         local name = info.name or " ";
 163                         if name ~= " " then
 164                                 name = ("%q"):format(name);
 165                         end
 166                         if func_type == "global " or func_type == "local " then
 167                                 func_type = func_type.."function ";
 168                         end
 169                         line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline).." in "..func_type..getstring(styles.funcname, name).." (defined on line "..info.linedefined..")";
 170                 end
 171                 if source_desc ~= last_source_desc then -- Venturing into a new source, add marker for previous
 172                         last_source_desc = source_desc;
 173                         table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));
 174                 end
 175                 nlevel = nlevel-1;
 176                 table.insert(lines, "\t"..(nlevel==0 and ">" or " ")..getstring(styles.level_num, "("..nlevel..") ")..line);
 177                 local npadding = (" "):rep(#tostring(nlevel));
 178                 if level.locals then
 179                         local locals_str = string_from_var_table(level.locals, optimal_line_length, "\t            "..npadding);
 180                         if locals_str then
 181                                 table.insert(lines, "\t    "..npadding.."Locals: "..locals_str);
 182                         end
 183                 end
 184                 local upvalues_str = string_from_var_table(level.upvalues, optimal_line_length, "\t            "..npadding);
 185                 if upvalues_str then
 186                         table.insert(lines, "\t    "..npadding.."Upvals: "..upvalues_str);
 187                 end
 188         end
 189
 190 --      table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));
 191
 192         return message.."stack traceback:\n"..table.concat(lines, "\n");
 193 end
 194
 195 function use()
 196         debug.traceback = traceback;
 197 end
 198
 199 return _M;