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--[[
Copyright (c) 2013 Scott Lembcke and Howling Moon Software
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
TODO:
* Print short function arguments as part of stack location.
* Bug: sometimes doesn't advance to next line (same line event reported multiple times).
* Do coroutines work as expected?
]]
local function pretty(obj, non_recursive)
if type(obj) == "string" then
return string.format("%q", obj)
elseif type(obj) == "table" and not non_recursive then
local str = "{"
for k, v in pairs(obj) do
local pair = pretty(k, true).." = "..pretty(v, true)
str = str..(str == "{" and pair or ", "..pair)
end
return str.."}"
else
return tostring(obj)
end
end
local help_message = [[
[return] - re-run last command
c(ontinue) - contiue execution
s(tep) - step forward by one line (into functions)
n(ext) - step forward by one line (skipping over functions)
p(rint) [expression] - execute the expression and print the result
f(inish) - step forward until exiting the current function
u(p) - move up the stack by one frame
d(own) - move down the stack by one frame
t(race) - print the stack trace
l(ocals) - print the function arguments, locals and upvalues.
h(elp) - print this message
]]
-- The stack level that cmd_* functions use to access locals or info
local LOCAL_STACK_LEVEL = 6
-- Extra stack frames to chop off.
-- Used for things like dbgcall() or the overridden assert/error functions
local stack_top = 0
-- The current stack frame index.
-- Changed using the up/down commands
local stack_offset = 0
-- Override if you don't want to use stdin
-- Override if you don't want to use stdout.
local function dbg_write(str, ...)
io.write(string.format(str, ...))
end
local function dbg_writeln(str, ...)
dbg_write((str or "").."\n", ...)
end
local function dbg_read(prompt)
dbg_write(prompt)
return io.read()
end
local function formatStackLocation(info)
local fname = (info.name or string.format("<%s:%d>", info.short_src, info.linedefined))
return string.format("%s:%d in function '%s'", info.short_src, info.currentline, fname)
end
local repl
local function hook_factory(repl_threshold)
return function(offset)
return function(event, line)
local info = debug.getinfo(2)
if event == "call" and info.linedefined >= 0 then
offset = offset + 1
elseif event == "return" and info.linedefined >= 0 then
if offset <= repl_threshold then
-- TODO this is what causes the duplicated lines
-- Don't remember why this is even here...
--repl()
else
offset = offset - 1
end
elseif event == "line" and offset <= repl_threshold then
repl()
end
end
end
end
local hook_step = hook_factory(1)
local hook_next = hook_factory(0)
local hook_finish = hook_factory(-1)
local function table_merge(t1, t2)
local tbl = {}
for k, v in pairs(t1) do tbl[k] = v end
for k, v in pairs(t2) do tbl[k] = v end
return tbl
end
local VARARG_SENTINEL = "(*varargs)"
local function local_bindings(offset, include_globals)
--[[ TODO
Need to figure out how to get varargs with LuaJIT
]]
local level = stack_offset + offset + LOCAL_STACK_LEVEL
local func = debug.getinfo(level).func
local bindings = {}
-- Retrieve the upvalues
do local i = 1; repeat
local name, value = debug.getupvalue(func, i)
if name then bindings[name] = value end
i = i + 1
until name == nil end
-- Retrieve the locals (overwriting any upvalues)
do local i = 1; repeat
local name, value = debug.getlocal(level, i)
if name then bindings[name] = value end
i = i + 1
until name == nil end
-- Retrieve the varargs. (only works in Lua 5.2)
local varargs = {}
do local i = -1; repeat
local name, value = debug.getlocal(level, i)
table.insert(varargs, value)
i = i - 1
until name == nil end
bindings[VARARG_SENTINEL] = varargs
if include_globals then
-- Merge the local bindings over the top of the environment table.
-- In Lua 5.2, you have to get the environment table from the function's locals.
local env = (_VERSION <= "Lua 5.1" and getfenv(func) or bindings._ENV)
-- Finally, merge the tables and add a lookup for globals.
return setmetatable(table_merge(env, bindings), {__index = _G})
else
return bindings
end
end
local function compile_chunk(expr, env)
if _VERSION <= "Lua 5.1" then
local chunk = loadstring("return "..expr, "<debugger repl>")
if chunk then setfenv(chunk, env) end
return chunk
else
-- The Lua 5.2 way is a bit cleaner
return load("return "..expr, "<debugger repl>", "t", env)
end
end
local function super_pack(...)
return select("#", ...), {...}
end
local function cmd_print(expr)
local env = local_bindings(1, true)
local chunk = compile_chunk(expr, env)
if chunk == nil then
dbg_writeln("Error: Could not evaluate expression.")
return false
end
local count, results = super_pack(pcall(chunk, unpack(env[VARARG_SENTINEL])))
if not results[1] then
dbg_writeln("Error: %s", results[2])
elseif count == 1 then
dbg_writeln("Error: No expression to execute")
else
local result = ""
for i=2, count do
result = result..(i ~= 2 and ", " or "")..pretty(results[i])
end
dbg_writeln(expr.." => "..result)
end
return false
end
local function cmd_up()
local info = debug.getinfo(stack_offset + LOCAL_STACK_LEVEL + 1)
if info then
stack_offset = stack_offset + 1
dbg_writeln("Inspecting frame: "..formatStackLocation(info))
else
dbg_writeln("Error: Already at the top of the stack.")
end
return false
end
local function cmd_down()
if stack_offset > stack_top then
stack_offset = stack_offset - 1
local info = debug.getinfo(stack_offset + LOCAL_STACK_LEVEL)
dbg_writeln("Inspecting frame: "..formatStackLocation(info))
else
dbg_writeln("Error: Already at the bottom of the stack.")
end
return false
end
local function cmd_trace()
local location = formatStackLocation(debug.getinfo(stack_offset + LOCAL_STACK_LEVEL))
local offset = stack_offset - stack_top
local message = string.format("Inspecting frame: %d - (%s)", offset, location)
dbg_writeln(debug.traceback(message, stack_offset + LOCAL_STACK_LEVEL))
return false
end
local function cmd_locals()
for k, v in pairs(local_bindings(1, false)) do
-- Don't print the Lua 5.2 __ENV local. It's pretty huge and useless to see.
if k ~= "_ENV" then
dbg_writeln("\t%s => %s", k, pretty(v))
end
end
return false
end
local function cmd_help()
dbg_writeln(help_message)
return false
end
local last_cmd = false
-- Run a command line
-- Returns true if the REPL should exit and the hook function factory
local function run_command(line)
-- Continue without caching the command if you hit control-d.
if line == nil then
dbg_writeln()
return true
end
-- Execute the previous command or cache it
if line == "" then
if last_cmd then return unpack({run_command(last_cmd)}) else return false end
else
last_cmd = line
end
local commands = {
["c"] = function() return true end,
["s"] = function() return true, hook_step end,
["n"] = function() return true, hook_next end,
["f"] = function() return true, hook_finish end,
["p%s?(.*)"] = cmd_print,
["u"] = cmd_up,
["d"] = cmd_down,
["t"] = cmd_trace,
["l"] = cmd_locals,
["h"] = cmd_help,
}
for cmd, cmd_func in pairs(commands) do
local matches = {string.match(line, "^("..cmd..")$")}
if matches[1] then
return unpack({cmd_func(select(2, unpack(matches)))})
end
end
dbg_writeln("Error: command '%s' not recognized", line)
return false
end
repl = function()
dbg_writeln(formatStackLocation(debug.getinfo(LOCAL_STACK_LEVEL - 3 + stack_top)))
repeat
local success, done, hook = pcall(run_command, dbg_read("debugger.lua> "))
if success then
debug.sethook(hook and hook(0), "crl")
else
local message = string.format("INTERNAL DEBUGGER.LUA ERROR. ABORTING\n: %s", done)
dbg_writeln(message)
error(message)
end
until done
end
local dbg = setmetatable({}, {
__call = function(self, condition, offset)
if condition then return end
offset = (offset or 0)
stack_offset = offset
stack_top = offset
debug.sethook(hook_next(1), "crl")
return
end,
})
dbg.write = dbg_write
dbg.writeln = dbg_writeln
dbg.pretty = pretty
function dbg.error(err, level)
level = level or 1
dbg_writeln("Debugger stopped on error(%s)", pretty(err))
dbg(false, level)
error(err, level)
end
function dbg.assert(condition, message)
if not condition then
dbg_writeln("Debugger stopped on assert(..., %s)", message)
dbg(false, 1)
end
assert(condition, message)
end
function dbg.call(f, l)
return (xpcall(f, function(err)
dbg_writeln("Debugger stopped on error: "..pretty(err))
dbg(false, (l or 0) + 1)
return
end))
end
local function luajit_load_readline_support()
local ffi = require("ffi")
ffi.cdef[[
void free(void *ptr);
char *readline(const char *);
int add_history(const char *);
]]
local readline = ffi.load("readline")
dbg_read = function(prompt)
local cstr = readline.readline(prompt)
if cstr ~= nil then
local str = ffi.string(cstr)
if string.match(str, "[^%s]+") then
readline.add_history(cstr)
end
ffi.C.free(cstr)
return str
else
return nil
end
end
dbg_writeln("Readline support loaded.")
end
if jit and
jit.version == "LuaJIT 2.0.0-beta10"
then
dbg_writeln("debugger.lua loaded for "..jit.version)
pcall(luajit_load_readline_support)
elseif
_VERSION == "Lua 5.2" or
_VERSION == "Lua 5.1"
then
dbg_writeln("debugger.lua loaded for ".._VERSION)
else
dbg_writeln("debugger.lua not tested against ".._VERSION)
dbg_writeln("Please send me feedback!")
end
return dbg
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