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