src/iolib.js: Create stdin/stdout/stderr

1 files changed, 40 insertions, 0 deletions

diff --git a/src/liolib.js b/src/liolib.js
index 22dc2e8..247baef 100644
--- a/src/liolib.js
+++ b/src/liolib.js
@@ -3,6 +3,23 @@
 const lua     = require('./lua.js');
 const lauxlib = require('./lauxlib.js');
 
+const IO_PREFIX = "_IO_";
+const IOPREF_LEN = IO_PREFIX.length;
+const IO_INPUT = lua.to_luastring(IO_PREFIX + "input");
+const IO_OUTPUT = lua.to_luastring(IO_PREFIX + "output");
+
+const tolstream = function(L) {
+    return lauxlib.luaL_checkudata(L, 1, lauxlib.LUA_FILEHANDLE);
+};
+
+const newprefile = function(L) {
+    let p = lua.lua_newuserdata(L);
+    p.f = null;
+    p.closef = null;
+    lauxlib.luaL_setmetatable(L, lauxlib.LUA_FILEHANDLE);
+    return p;
+};
+
 const iolib = {
 };
 
@@ -17,9 +34,32 @@ const createmeta = function(L) {
     lua.lua_pop(L, 1);  /* pop new metatable */
 };
 
+const io_noclose = function(L) {
+    let p = tolstream(L);
+    p.closef = io_noclose;
+    lua.lua_pushnil(L);
+    lua.lua_pushliteral(L, "cannot close standard file");
+    return 2;
+};
+
+const createstdfile = function(L, f, k, fname) {
+    let p = newprefile(L);
+    p.f = f;
+    p.closef = io_noclose;
+    if (k !== null) {
+        lua.lua_pushvalue(L, -1);
+        lua.lua_setfield(L, lua.LUA_REGISTRYINDEX, k);  /* add file to registry */
+    }
+    lua.lua_setfield(L, -2, fname);  /* add file to module */
+};
+
 const luaopen_io = function(L) {
     lauxlib.luaL_newlib(L, iolib);
     createmeta(L);
+    /* create (and set) default files */
+    createstdfile(L, process.stdin, IO_INPUT, lua.to_luastring("stdin"));
+    createstdfile(L, process.stdout, IO_OUTPUT, lua.to_luastring("stdout"));
+    createstdfile(L, process.stderr, null, lua.to_luastring("stderr"));
     return 1;
 };