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