[osx.c] Rework directory iteration.

- add opendir() to open a directory and return it.
- add directory listfiles() method, returning all remaining entries as
  an array
- rework directory iteration

osx.c

@@ -193,9 +193,7 @@ static bool os_dir_filter(lua_State *L, const char *name)
     return result;
 }
 
-static int os_dir_iter(lua_State *L);
-
-static int os_dir(lua_State *L)
+static int os_dir_open(lua_State *L)
 {
     const char *path = luaL_checkstring(L, 1);
 
@@ -204,9 +202,42 @@ static int os_dir(lua_State *L)
     dir->hn = os_opendir(path);
     dir->closeflag = false;
     if (!dir->hn)
-        luaL_error(L, "%s: %s", path, strerror(errno));
+        return os_pushfail(L, path);
 
     luaL_setmetatable(L, DF_LUA_DIRHANDLE);
+    return 1;
+}
+
+static int os_dir_close(lua_State *L)
+{
+    df_os_dir *dir = todir(L);
+
+    os_closedir(dir->hn);
+    dir->closeflag = true;
+    return 0;
+}
+
+static int os_dir_gc(lua_State *L)
+{
+    df_os_dir *dir = luaL_checkudata(L, 1, DF_LUA_DIRHANDLE);
+
+    if (!dir->closeflag)
+        os_dir_close(L);
+
+    return 0;
+}
+
+static int os_dir_iter(lua_State *L);
+
+static int os_dir(lua_State *L)
+{
+    lua_pushcfunction(L, os_dir_open);
+    lua_pushvalue(L, 1);
+    lua_call(L, 1, 2);
+    if (lua_isnil(L, -2))
+        lua_error(L);
+
+    lua_pop(L, 1);
 
     lua_pushcclosure(L, os_dir_iter, 2);
     return 1;
@@ -239,7 +270,7 @@ nextfilename:
     return 1;
 }
 
-static int os_dir_read(lua_State *L)
+static int os_dir_readdir(lua_State *L)
 {
     df_os_dir *dir = todir(L);
 
@@ -253,28 +284,9 @@ static int os_dir_read(lua_State *L)
     return 1;
 }
 
-static int os_dir_close(lua_State *L)
+static int os_dir_dolistfiles(lua_State *L, bool closeflag, const char *path)
 {
     df_os_dir *dir = todir(L);
-
-    os_closedir(dir->hn);
-    dir->closeflag = true;
-    return 0;
-}
-
-static int os_dir_gc(lua_State *L)
-{
-    df_os_dir *dir = luaL_checkudata(L, 1, DF_LUA_DIRHANDLE);
-
-    if (!dir->closeflag)
-        os_dir_close(L);
-
-    return 0;
-}
-
-static int os_listfiles(lua_State *L)
-{
-    const char *path = luaL_checkstring(L, 1);
     bool dofilter = false;
 
     if (!lua_isnoneornil(L, 2)) {
@@ -282,18 +294,13 @@ static int os_listfiles(lua_State *L)
         dofilter = true;
     }
 
-    df_os_dirhn hn = os_opendir(path);
-    if (!hn)
-        return os_pushfail(L, path);
+    char *filename;
+    int i = 1;
 
     lua_newtable(L);
 
-    const char *filename;
-    int i = 1;
-    int err;
-
     errno = 0;
-    while ((filename = os_readdir(hn)) != NULL) {
+    while ((filename = os_readdir(dir->hn)) != NULL) {
         if (strcmp(filename, ".") == 0 || strcmp(filename, "..") == 0)
             continue;
         if (dofilter && !os_dir_filter(L, filename))
@@ -303,15 +310,40 @@ static int os_listfiles(lua_State *L)
         lua_pushstring(L, filename);
         lua_settable(L, -3);
     }
-    err = errno;
 
-    os_closedir(hn);
-    if (err != 0)
+    int err = errno;
+    if (closeflag)
+        os_dir_close(L);
+    if (err != 0) {
+        errno = err;
         return os_pushfail(L, path);
-
+    }
     return 1;
 }
 
+static int os_dir_listfiles(lua_State *L)
+{
+    return os_dir_dolistfiles(L, false, NULL);
+}
+
+static int os_listfiles(lua_State *L)
+{
+    const char *path = luaL_checkstring(L, 1);
+    if (lua_isnone(L, 2))
+        lua_pushnil(L);
+
+    lua_pushcfunction(L, os_dir_open);
+    lua_pushvalue(L, 1);
+    lua_call(L, 1, 2);
+    if (lua_isnil(L, -2))
+        lua_error(L);
+
+    lua_copy(L, -2, 1);
+    lua_pop(L, 2);
+
+    return os_dir_dolistfiles(L, true, path);
+}
+
 static int os_stat(lua_State *L)
 {
     const char *path = NULL;
@@ -517,7 +549,8 @@ static void createmeta(lua_State *L)
         { NULL, NULL }
     };
     static const luaL_Reg meth[] = {
-        { "read", os_dir_read },
+        { "readdir", os_dir_readdir },
+        { "listfiles", os_dir_listfiles },
         { "close", os_dir_close },
         { NULL, NULL }
     };
@@ -534,6 +567,7 @@ DF_OSXMOD_API int luaopen_osx(lua_State *L)
 {
     static const luaL_Reg funcs[] = {
         { "listfiles", os_listfiles },
+        { "opendir", os_dir_open },
         { "dir", os_dir },
         { "stat", os_stat },
         { "mkdir", os_mkdir },