adjust file metatables even in compat53.module mode (#67)

* adjust file metatables even in compat53.module mode

* apply tweaks only to LuaJIT; file:write() only to compat=none

compat53/file_mt.lua

@@ -0,0 +1,71 @@
+local lua_version = _VERSION:sub(-3)
+
+local M = {}
+
+local unpack = lua_version == "5.1" and unpack or table.unpack
+
+local function addasterisk(fmt)
+   if type(fmt) == "string" and fmt:sub(1, 1) ~= "*" then
+      return "*"..fmt
+   else
+      return fmt
+   end
+end
+
+function M.update_file_meta(file_meta, is_luajit52)
+
+   -- make '*' optional for file:read and file:lines
+
+   local file_lines = file_meta.__index.lines
+   file_meta.__index.lines = function(self, ...)
+      local n = select('#', ...)
+      for i = 1, n do
+         local a = select(i, ...)
+         local b = addasterisk(a)
+         -- as an optimization we only allocate a table for the
+         -- modified format arguments when we have a '*' somewhere
+         if a ~= b then
+            local args = { ... }
+            args[i] = b
+            for j = i+1, n do
+               args[j] = addasterisk(args[j])
+            end
+            return file_lines(self, unpack(args, 1, n))
+         end
+      end
+      return file_lines(self, ...)
+   end
+
+   local file_read = file_meta.__index.read
+   file_meta.__index.read = function(self, ...)
+      local n = select('#', ...)
+      for i = 1, n do
+         local a = select(i, ...)
+         local b = addasterisk(a)
+         -- as an optimization we only allocate a table for the
+         -- modified format arguments when we have a '*' somewhere
+         if a ~= b then
+            local args = { ... }
+            args[i] = b
+            for j = i+1, n do
+               args[j] = addasterisk(args[j])
+            end
+            return file_read(self, unpack(args, 1, n))
+         end
+      end
+      return file_read(self, ...)
+   end
+
+   if not is_luajit52 then
+      local file_write = file_meta.__index.write
+      file_meta.__index.write = function(self, ...)
+         local ret, err = file_write(self, ...)
+         if ret then
+            return self
+         end
+         return ret, err
+      end
+   end
+end
+
+return M

compat53/init.lua

@@ -17,57 +17,15 @@ if lua_version < "5.3" then
    local file_meta = gmt(io.stdout)
 
 
-   -- make '*' optional for file:read and file:lines
-   if type(file_meta) == "table" and type(file_meta.__index) == "table" then
-
-      local function addasterisk(fmt)
-         if type(fmt) == "string" and fmt:sub(1, 1) ~= "*" then
-            return "*"..fmt
-         else
-            return fmt
-         end
-      end
-
-      local file_lines = file_meta.__index.lines
-      file_meta.__index.lines = function(self, ...)
-         local n = select('#', ...)
-         for i = 1, n do
-            local a = select(i, ...)
-            local b = addasterisk(a)
-            -- as an optimization we only allocate a table for the
-            -- modified format arguments when we have a '*' somewhere
-            if a ~= b then
-               local args = { ... }
-               args[i] = b
-               for j = i+1, n do
-                  args[j] = addasterisk(args[j])
-               end
-               return file_lines(self, unpack(args, 1, n))
-            end
-         end
-         return file_lines(self, ...)
-      end
+   -- detect LuaJIT (including LUAJIT_ENABLE_LUA52COMPAT compilation flag)
+   local is_luajit = (string.dump(function() end) or ""):sub(1, 3) == "\027LJ"
+   local is_luajit52 = is_luajit and
+     #setmetatable({}, { __len = function() return 1 end }) == 1
 
-      local file_read = file_meta.__index.read
-      file_meta.__index.read = function(self, ...)
-         local n = select('#', ...)
-         for i = 1, n do
-            local a = select(i, ...)
-            local b = addasterisk(a)
-            -- as an optimization we only allocate a table for the
-            -- modified format arguments when we have a '*' somewhere
-            if a ~= b then
-               local args = { ... }
-               args[i] = b
-               for j = i+1, n do
-                  args[j] = addasterisk(args[j])
-               end
-               return file_read(self, unpack(args, 1, n))
-            end
-         end
-         return file_read(self, ...)
-      end
 
+   if type(file_meta) == "table" and type(file_meta.__index) == "table" then
+      local file_mt = require("compat53.file_mt")
+      file_mt.update_file_meta(file_meta, is_luajit52)
    end -- got a valid metatable for file objects
 
 
@@ -85,12 +43,6 @@ if lua_version < "5.3" then
       local io_type = io.type
 
 
-      -- detect LuaJIT (including LUAJIT_ENABLE_LUA52COMPAT compilation flag)
-      local is_luajit = (string.dump(function() end) or ""):sub(1, 3) == "\027LJ"
-      local is_luajit52 = is_luajit and
-        #setmetatable({}, { __len = function() return 1 end }) == 1
-
-
       -- make package.searchers available as an alias for package.loaders
       local p_index = { searchers = package.loaders }
       setmetatable(package, {

compat53/module.lua

@@ -13,7 +13,11 @@ if lua_version < "5.3" then
          debug, io, math, package, string, table
    local io_lines = io.lines
    local io_read = io.read
+   local io_open = io.open
+   local io_popen = io.popen
+   local io_tmpfile = io.tmpfile
    local unpack = lua_version == "5.1" and unpack or table.unpack
+   local debug_setmetatable = type(debug) == "table" and debug.setmetatable
 
    -- create module table
    M = {}
@@ -451,7 +455,6 @@ if lua_version < "5.3" then
       if type(debug) == "table" then
          local debug_setfenv = debug.setfenv
          local debug_getfenv = debug.getfenv
-         local debug_setmetatable = debug.setmetatable
 
          M.debug = setmetatable({}, { __index = debug })
 
@@ -823,6 +826,67 @@ if lua_version < "5.3" then
          end
       end -- not luajit
 
+      if is_luajit then
+         local compat_file_meta = {}
+         local compat_file_meta_loaded = false
+
+         local function load_compat_file_meta(file_meta)
+            -- fill compat_file_meta with original entries
+            for k, v in pairs(file_meta) do
+               compat_file_meta[k] = v
+            end
+            compat_file_meta.__index = {}
+            for k, v in pairs(file_meta.__index) do
+               compat_file_meta.__index[k] = v
+            end
+
+            -- update it with compatibility functions
+            local file_mt = require("compat53.file_mt")
+            file_mt.update_file_meta(compat_file_meta, is_luajit52)
+
+            compat_file_meta_loaded = true
+         end
+
+         function M.io.open(...)
+            local fd, err = io_open(...)
+            if fd and debug_setmetatable then
+               if not compat_file_meta_loaded then
+                  local file_meta = gmt(fd)
+                  load_compat_file_meta(file_meta)
+               end
+               debug_setmetatable(fd, compat_file_meta)
+            end
+
+            return fd, err
+         end
+
+         function M.io.popen(...)
+            local fd, err = io_popen(...)
+            if fd and debug_setmetatable then
+               if not compat_file_meta_loaded then
+                  local file_meta = gmt(fd)
+                  load_compat_file_meta(file_meta)
+               end
+               debug_setmetatable(fd, compat_file_meta)
+            end
+
+            return fd, err
+         end
+
+         function M.io.tmpfile(...)
+            local fd, err = io_tmpfile(...)
+            if fd and debug_setmetatable then
+               if not compat_file_meta_loaded then
+                  local file_meta = gmt(fd)
+                  load_compat_file_meta(file_meta)
+               end
+               debug_setmetatable(fd, compat_file_meta)
+            end
+
+            return fd, err
+         end
+      end
+
    end -- lua 5.1
 
    -- further write should be forwarded to _G

liolib.c

@@ -142,7 +142,7 @@ static int l_checkmode (const char *mode) {
 typedef luaL_Stream LStream;
 
 
-#define tolstream(L)	((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
+#define tolstream(L)	(luaL_checktype(L, 1, LUA_TUSERDATA), (LStream *)lua_touserdata(L, 1))
 
 #define isclosed(p)	((p)->closef == NULL)
 

rockspecs/compat53-scm-0.rockspec

@@ -24,6 +24,7 @@ build = {
    modules = {
       ["compat53.init"] = "compat53/init.lua",
       ["compat53.module"] = "compat53/module.lua",
+      ["compat53.file_mt"] = "compat53/file_mt.lua",
       ["compat53.utf8"] = "lutf8lib.c",
       ["compat53.table"] = "ltablib.c",
       ["compat53.string"] = "lstrlib.c",

tests/test.lua

@@ -36,6 +36,8 @@ end
 local V = _VERSION:gsub("^.*(%d+)%.(%d+)$", "%1%2")
 if jit then V = "jit" end
 
+local is_puclua51 = (_VERSION == "Lua 5.1" and not jit)
+
 local mode = "global"
 if arg[1] == "module" then
   mode = "module"
@@ -576,7 +578,7 @@ ___''
 do
    print("io.write()", io.type(io.write("hello world\n")))
    local f = assert(io.tmpfile())
-   print("file:write()", io.type(f:write("hello world\n")))
+   print("io.tmpfile => file:write()", io.type(f:write("hello world\n")))
    f:close()
 end
 
@@ -589,13 +591,18 @@ do
    io.input("data.txt")
    print("io.read()", io.read("n", "number", "l", "a"))
    io.input(io.stdin)
-   if mode ~= "module" then
-     local f = assert(io.open("data.txt", "r"))
-     print("file:read()", f:read("*n", "*number", "*l", "*a"))
-     f:close()
-     f = assert(io.open("data.txt", "r"))
-     print("file:read()", f:read("n", "number", "l", "a"))
-     f:close()
+   if not is_puclua51 then
+      local f = assert(io.open("data.txt", "r"))
+      print("file:read()", f:read("*n", "*number", "*l", "*a"))
+      f:close()
+      f = assert(io.open("data.txt", "r"))
+      print("file:read()", f:read("n", "number", "l", "a"))
+      f:close()
+      os.remove("data.txt")
+
+      local g = assert(io.open("data.txt", "w"))
+      print("io.open => file:write()", type(g:write("hello")))
+      g:close()
    end
    os.remove("data.txt")
 end