Lua debugger part 1

debugger/apis/init.lua

@@ -0,0 +1,201 @@
+--[[
+some portions from https://github.com/slembcke/debugger.lua
+]]
+
+local fs = _G.fs
+
+local dbg = { }
+
+local function hookBreakpoint(info)
+	if dbg.breakpoints then
+		for _,v in pairs(dbg.breakpoints) do
+			if v.line == info.currentline and v.file == info.short_src then
+				return true
+			end
+		end
+	end
+end
+
+local function hookFunction(fn)
+	return function(info)
+		return info.func == fn
+	end
+end
+
+local function hookStep()
+	local co = coroutine.running()
+	return function()
+		return co == coroutine.running()
+	end
+end
+
+local function hookStepStacksize(n)
+	local co = coroutine.running()
+	local i = 2
+	while true do
+		local info = debug.getinfo(i)
+		if not info then
+			break
+		end
+		i = i + 1
+	end
+	return function()
+		if co == coroutine.running() then
+			if not debug.getinfo(i - n) then
+				return true
+			end
+		end
+	end
+end
+
+local function hookStepOut()
+	return hookStepStacksize(1)
+end
+
+local function hookStepOver()
+	return hookStepStacksize(0)
+end
+
+local hookEval = function() end
+
+-- Create a table of all the locally accessible variables.
+-- Globals are not included when running the locals command
+local function local_bindings(offset, stack_inspect_offset)
+	offset = offset + 1 + stack_inspect_offset -- add this function to the offset
+	local func = debug.getinfo(offset).func
+	local bindings = {}
+
+	-- Retrieve the upvalues
+	do local i = 1; while true do
+		local name, value = debug.getupvalue(func, i)
+		if not name then break end
+		bindings[name] = value
+		i = i + 1
+	end end
+
+	-- Retrieve the locals (overwriting any upvalues)
+	do local i = 1; while true do
+		local name, value = debug.getlocal(offset, i)
+		if not name then break end
+		bindings[name] = value
+		i = i + 1
+	end end
+
+	-- Retrieve the varargs (works in Lua 5.2 and LuaJIT)
+	local varargs = {}
+	do local i = 1; while true do
+		local name, value = debug.getlocal(offset, -i)
+		if not name then break end
+		varargs[i] = value
+		i = i + 1
+	end end
+	if #varargs > 0 then bindings["..."] = varargs end
+
+	return bindings
+end
+
+local function get_trace(offset, stack_inspect_offset)
+	local function format_loc(file, line) return file..":"..line end
+	local function format_stack_frame_info(info)
+		local filename = info.source:match("@(.*)")
+		local source = filename and fs.getName(filename) or info.short_src
+		local namewhat = (info.namewhat == "" and "chunk at" or info.namewhat)
+		local name = (info.name and "'"..info.name.."'" or format_loc(source, info.linedefined))
+		return format_loc(source, info.currentline).." in "..namewhat.." "..name
+	end
+
+	offset = offset + 1 -- add this function to the offset
+	local t = { }
+	local i = 0
+	while true do
+		local info = debug.getinfo(offset + i)
+		if not info then break end
+		t[i] = {
+			index = i,
+			current = (i == stack_inspect_offset),
+			desc = format_stack_frame_info(info),
+			info = info,
+		}
+		i = i + 1
+	end
+
+	return t
+end
+
+local inHook = false
+
+local function hook()
+	local info = debug.getinfo(2)
+	if info.currentline < 0 then
+		return
+	end
+	if not inHook and hookEval(info) then
+		inHook = true
+
+		local offset = 2  -- the offset from this function to the code being debugged
+		local inspectOffset = 0
+
+		repeat
+			local done = true
+			local snapshot = {
+				info = debug.getinfo(offset + inspectOffset),
+				locals = local_bindings(offset, inspectOffset),
+				stack = get_trace(offset, inspectOffset),
+			}
+
+			inspectOffset = 0 -- reset
+
+			local cmd, param = dbg.read(snapshot)
+			if cmd == 's' then
+				hookEval = hookStep()
+			elseif cmd == 'n' then
+				hookEval = hookStepOver()
+			elseif cmd == 'f' then
+				hookEval = hookStepOut()
+			elseif cmd == 'c' then
+				hookEval = hookBreakpoint
+			elseif cmd == 'd' then         -- detach
+				debug.sethook()
+			elseif cmd == 'q' then
+				os.exit(0)
+			elseif cmd == 'b' then
+				dbg.breakpoints = param
+				done = false
+			elseif cmd == 'i' then
+				-- inspect stack at this offset
+				inspectOffset = param
+				done = false
+			end
+		until done
+
+		inHook = false
+	end
+end
+
+debug.sethook(hook, 'l')
+
+-- Expose the debugger's functions
+dbg.hook = hook
+dbg.exit = function(err) os.exit(err) end
+dbg.stopIn = function(fn)
+	hookEval = hookFunction(fn)
+end
+dbg.debugger = nil
+
+dbg.read = function(info)
+	_G._pinfo = info
+
+	os.sleep(0)  -- this is important ...
+	dbg.debugger:resume('debugger', 'info', info)
+
+	while true do
+		local _, cmd, args = os.pullEvent('debugger')
+		if cmd == 'b' then
+			dbg.breakpoints = args
+		else
+			return cmd, args
+		end
+	end
+end
+
+return dbg