1 files changed, 199 insertions, 0 deletions
diff --git a/util/debug.lua b/util/debug.lua
new file mode 100644
index 00000000..91f691e1
--- /dev/null
+++ b/util/debug.lua
@@ -0,0 +1,199 @@
+-- Variables ending with these names will not
+-- have their values printed ('password' includes
+-- 'new_password', etc.)
+local censored_names = {
+	password = true;
+	passwd = true;
+	pass = true;
+	pwd = true;
+};
+local optimal_line_length = 65;
+
+local termcolours = require "util.termcolours";
+local getstring = termcolours.getstring;
+local styles;
+do
+	_ = termcolours.getstyle;
+	styles = {
+		boundary_padding = _("bright");
+		filename         = _("bright", "blue");
+		level_num        = _("green");
+		funcname         = _("yellow");
+		location         = _("yellow");
+	};
+end
+module("debugx", package.seeall);
+
+function get_locals_table(thread, level)
+	local locals = {};
+	for local_num = 1, math.huge do
+		local name, value;
+		if thread then
+			name, value = debug.getlocal(thread, level, local_num);
+		else
+			name, value = debug.getlocal(level+1, local_num);
+		end
+		if not name then break; end
+		table.insert(locals, { name = name, value = value });
+	end
+	return locals;
+end
+
+function get_upvalues_table(func)
+	local upvalues = {};
+	if func then
+		for upvalue_num = 1, math.huge do
+			local name, value = debug.getupvalue(func, upvalue_num);
+			if not name then break; end
+			table.insert(upvalues, { name = name, value = value });
+		end
+	end
+	return upvalues;
+end
+
+function string_from_var_table(var_table, max_line_len, indent_str)
+	local var_string = {};
+	local col_pos = 0;
+	max_line_len = max_line_len or math.huge;
+	indent_str = "\n"..(indent_str or "");
+	for _, var in ipairs(var_table) do
+		local name, value = var.name, var.value;
+		if name:sub(1,1) ~= "(" then
+			if type(value) == "string" then
+				if censored_names[name:match("%a+$")] then
+					value = "<hidden>";
+				else
+					value = ("%q"):format(value);
+				end
+			else
+				value = tostring(value);
+			end
+			if #value > max_line_len then
+				value = value:sub(1, max_line_len-3).."…";
+			end
+			local str = ("%s = %s"):format(name, tostring(value));
+			col_pos = col_pos + #str;
+			if col_pos > max_line_len then
+				table.insert(var_string, indent_str);
+				col_pos = 0;
+			end
+			table.insert(var_string, str);
+		end
+	end
+	if #var_string == 0 then
+		return nil;
+	else
+		return "{ "..table.concat(var_string, ", "):gsub(indent_str..", ", indent_str).." }";
+	end
+end
+
+function get_traceback_table(thread, start_level)
+	local levels = {};
+	for level = start_level, math.huge do
+		local info;
+		if thread then
+			info = debug.getinfo(thread, level);
+		else
+			info = debug.getinfo(level+1);
+		end
+		if not info then break; end
+
+		levels[(level-start_level)+1] = {
+			level = level;
+			info = info;
+			locals = get_locals_table(thread, level+(thread and 0 or 1));
+			upvalues = get_upvalues_table(info.func);
+		};
+	end
+	return levels;
+end
+
+function traceback(...)
+	local ok, ret = pcall(_traceback, ...);
+	if not ok then
+		return "Error in error handling: "..ret;
+	end
+	return ret;
+end
+
+local function build_source_boundary_marker(last_source_desc)
+	local padding = string.rep("-", math.floor(((optimal_line_length - 6) - #last_source_desc)/2));
+	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 "));
+end
+
+function _traceback(thread, message, level)
+
+	-- Lua manual says: debug.traceback ([thread,] [message [, level]])
+	-- I fathom this to mean one of:
+	-- ()
+	-- (thread)
+	-- (message, level)
+	-- (thread, message, level)
+
+	if thread == nil then -- Defaults
+		thread, message, level = coroutine.running(), message, level;
+	elseif type(thread) == "string" then
+		thread, message, level = coroutine.running(), thread, message;
+	elseif type(thread) ~= "thread" then
+		return nil; -- debug.traceback() does this
+	end
+
+	level = level or 0;
+
+	message = message and (message.."\n") or "";
+
+	-- +3 counts for this function, and the pcall() and wrapper above us, the +1... I don't know.
+	local levels = get_traceback_table(thread, level+(thread == nil and 4 or 0));
+
+	local last_source_desc;
+
+	local lines = {};
+	for nlevel, level in ipairs(levels) do
+		local info = level.info;
+		local line = "...";
+		local func_type = info.namewhat.." ";
+		local source_desc = (info.short_src == "[C]" and "C code") or info.short_src or "Unknown";
+		if func_type == " " then func_type = ""; end;
+		if info.short_src == "[C]" then
+			line = "[ C ] "..func_type.."C function "..getstring(styles.location, (info.name and ("%q"):format(info.name) or "(unknown name)"));
+		elseif info.what == "main" then
+			line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline);
+		else
+			local name = info.name or " ";
+			if name ~= " " then
+				name = ("%q"):format(name);
+			end
+			if func_type == "global " or func_type == "local " then
+				func_type = func_type.."function ";
+			end
+			line = "[Lua] "..getstring(styles.location, info.short_src.." line "..info.currentline).." in "..func_type..getstring(styles.funcname, name).." (defined on line "..info.linedefined..")";
+		end
+		if source_desc ~= last_source_desc then -- Venturing into a new source, add marker for previous
+			last_source_desc = source_desc;
+			table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));
+		end
+		nlevel = nlevel-1;
+		table.insert(lines, "\t"..(nlevel==0 and ">" or " ")..getstring(styles.level_num, "("..nlevel..") ")..line);
+		local npadding = (" "):rep(#tostring(nlevel));
+		if level.locals then
+			local locals_str = string_from_var_table(level.locals, optimal_line_length, "\t            "..npadding);
+			if locals_str then
+				table.insert(lines, "\t    "..npadding.."Locals: "..locals_str);
+			end
+		end
+		local upvalues_str = string_from_var_table(level.upvalues, optimal_line_length, "\t            "..npadding);
+		if upvalues_str then
+			table.insert(lines, "\t    "..npadding.."Upvals: "..upvalues_str);
+		end
+	end
+
+--	table.insert(lines, "\t "..build_source_boundary_marker(last_source_desc));
+
+	return message.."stack traceback:\n"..table.concat(lines, "\n");
+end
+
+function use()
+	debug.traceback = traceback;
+end
+
+return _M;