util.require: A replacement for Lua's require/module that doesn't load into the global environment by default (C modules still get past this)

1 files changed, 237 insertions, 0 deletions

diff --git a/util/require.lua b/util/require.lua
new file mode 100644
index 00000000..e09e6c1b
--- /dev/null
+++ b/util/require.lua
@@ -0,0 +1,237 @@
+-- Prosody IM
+-- Copyright (C) 2008-2009 Matthew Wild
+-- Copyright (C) 2008-2009 Waqas Hussain
+-- 
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+-- Based on Kepler Compat-5.1 code
+-- Copyright Kepler Project 2004-2006 (http://www.keplerproject.org/compat)
+-- $Id: compat-5.1.lua,v 1.22 2006/02/20 21:12:47 carregal Exp $
+--
+
+local LUA_DIRSEP = '/'
+local LUA_OFSEP = '_'
+local OLD_LUA_OFSEP = ''
+local POF = 'luaopen_'
+local LUA_PATH_MARK = '?'
+local LUA_IGMARK = ':'
+
+local assert, error, getfenv, ipairs, loadfile, loadlib, pairs, setfenv, setmetatable, type = assert, error, getfenv, ipairs, loadfile, loadlib, pairs, setfenv, setmetatable, type
+local find, format, gfind, gsub, sub = string.find, string.format, string.gfind, string.gsub, string.sub
+
+if package.nonglobal_module then return; end
+package.nonglobal_module = true;
+
+local _PACKAGE = package
+local _LOADED = package.loaded
+local _PRELOAD = package.preload
+
+--
+-- looks for a file `name' in given path
+--
+local function findfile (name, pname)
+	name = gsub (name, "%.", LUA_DIRSEP)
+	local path = _PACKAGE[pname]
+	assert (type(path) == "string", format ("package.%s must be a string", pname))
+	for c in gfind (path, "[^;]+") do
+		c = gsub (c, "%"..LUA_PATH_MARK, name)
+		local f = io.open (c)
+		if f then
+			f:close ()
+			return c
+		end
+	end
+	return nil -- not found
+end
+
+
+--
+-- check whether library is already loaded
+--
+local function loader_preload (name)
+	assert (type(name) == "string", format (
+		"bad argument #1 to `require' (string expected, got %s)", type(name)))
+	assert (type(_PRELOAD) == "table", "`package.preload' must be a table")
+	return _PRELOAD[name]
+end
+
+
+--
+-- Lua library loader
+--
+local function loader_Lua (name)
+	assert (type(name) == "string", format (
+		"bad argument #1 to `require' (string expected, got %s)", type(name)))
+	local filename = findfile (name, "path")
+	if not filename then
+		return false
+	end
+	local f, err = loadfile (filename)
+	if not f then
+		error (format ("error loading module `%s' (%s)", name, err))
+	end
+	return f
+end
+
+
+local function mkfuncname (name)
+	name = gsub (name, "^.*%"..LUA_IGMARK, "")
+	name = gsub (name, "%.", LUA_OFSEP)
+	return POF..name
+end
+
+local function old_mkfuncname (name)
+	--name = gsub (name, "^.*%"..LUA_IGMARK, "")
+	name = gsub (name, "%.", OLD_LUA_OFSEP)
+	return POF..name
+end
+
+--
+-- C library loader
+--
+local function loader_C (name)
+	assert (type(name) == "string", format (
+		"bad argument #1 to `require' (string expected, got %s)", type(name)))
+	local filename = findfile (name, "cpath")
+	if not filename then
+		return false
+	end
+	local funcname = mkfuncname (name)
+	local f, err = loadlib (filename, funcname)
+	if not f then
+		funcname = old_mkfuncname (name)
+		f, err = loadlib (filename, funcname)
+		if not f then
+			error (format ("error loading module `%s' (%s)", name, err))
+		end
+	end
+	return f
+end
+
+
+local function loader_Croot (name)
+	local p = gsub (name, "^([^.]*).-$", "%1")
+	if p == "" then
+		return
+	end
+	local filename = findfile (p, "cpath")
+	if not filename then
+		return
+	end
+	local funcname = mkfuncname (name)
+	local f, err, where = loadlib (filename, funcname)
+	if f then
+		return f
+	elseif where ~= "init" then
+		error (format ("error loading module `%s' (%s)", name, err))
+	end
+end
+
+-- create `loaders' table
+package.loaders = package.loaders or { loader_preload, loader_Lua, loader_C, loader_Croot, }
+local _LOADERS = package.loaders
+
+
+--
+-- iterate over available loaders
+--
+local function load (name, loaders)
+	-- iterate over available loaders
+	assert (type (loaders) == "table", "`package.loaders' must be a table")
+	for i, loader in ipairs (loaders) do
+		local f = loader (name)
+		if f then
+			return f
+		end
+	end
+	error (format ("module `%s' not found", name))
+end
+
+-- sentinel
+local sentinel = function () end
+
+local old_require = _G.require;
+local dep_path = {};
+local current_env = nil;
+function _G.require(modname)
+	--table.insert(dep_path, modname);
+	--if getfenv(2) == getfenv(0) --[[and rawget(_G, "__locked")]] then
+	--	print("**** Uh-oh, require called from locked global env at "..table.concat(dep_path, "->"), debug.traceback());
+	--end
+	if not current_env and rawget(_G, "__locked") then
+		_G.prosody.unlock_globals();
+		_G.__locked = false;
+	end
+	local old_current_env;
+	old_current_env, current_env = current_env, getfenv(2);
+	local ok, ret = pcall(old_require, modname);
+	current_env = old_current_env;
+	if not current_env and rawget(_G, "__locked") == false then
+		_G.prosody.lock_globals();
+	end
+	--table.remove(dep_path);
+	if not ok then error(ret, 0); end
+	return ret;
+end
+
+
+-- findtable
+local function findtable (t, f)
+	assert (type(f)=="string", "not a valid field name ("..tostring(f)..")")
+	local ff = f.."."
+	local ok, e, w = find (ff, '(.-)%.', 1)
+	while ok do
+		local nt = rawget (t, w)
+		if not nt then
+			nt = {}
+			t[w] = nt
+		elseif type(t) ~= "table" then
+			return sub (f, e+1)
+		end
+		t = nt
+		ok, e, w = find (ff, '(.-)%.', e+1)
+	end
+	return t
+end
+
+--
+-- new package.seeall function
+--
+function _PACKAGE.seeall (module)
+	local t = type(module)
+	assert (t == "table", "bad argument #1 to package.seeall (table expected, got "..t..")")
+	local meta = getmetatable (module)
+	if not meta then
+		meta = {}
+		setmetatable (module, meta)
+	end
+	meta.__index = _G
+end
+
+
+--
+-- new module function
+--
+function _G.module (modname, ...)
+	local ns = _LOADED[modname];
+	if type(ns) ~= "table" then
+		--if not current_env then
+		--	print("module outside require for "..modname.." at "..debug.traceback());
+		--end
+		ns = findtable (current_env or getfenv(2), modname);
+		if not ns then
+			error (string.format ("name conflict for module '%s'", modname))
+		end
+		_LOADED[modname] = ns
+	end
+	if not ns._NAME then
+		ns._NAME = modname
+		ns._M = ns
+		ns._PACKAGE = gsub (modname, "[^.]*$", "")
+	end
+	setfenv (2, ns)
+	for i, f in ipairs (arg) do
+		f (ns)
+	end
+end