# HG changeset patch
# User jbe
# Date 1427384310 -3600
# Node ID b1748c6c3c89ea09d0248c5d2081a7ee30aea509
# Parent  e00d11c12b689e665bb857a2aaea60a897689177
extos.stat(...) returns false (instead of nil) if file does not exist; Added extos.lstat(...) and extos.fstat(...)

diff -r e00d11c12b68 -r b1748c6c3c89 libraries/extos/extos.autodoc.lua
--- a/libraries/extos/extos.autodoc.lua	Thu Mar 26 12:26:00 2015 +0100
+++ b/libraries/extos/extos.autodoc.lua	Thu Mar 26 16:38:30 2015 +0100
@@ -20,13 +20,30 @@
 
 
 --[[--
-filestat_table,  -- table with information on the file
-errmsg =         -- error message if file information could not be read
+directory_entries,  -- table of directory entries
+errmsg =            -- error message if directory could not be read
+extos.listdir(
+  path              -- path name
+)
+
+This function returns a table containing strings representing each entry in a directory. On error nil and an error message are returned.
+
+--]]--
+-- implemented in extos.c as
+-- static int extos_listdir(lua_State *L)
+--//--
+
+
+--[[--
+filestat_table,  -- table with information on the file, false if file does not exist, nil on error
+errmsg =         -- error message if file information could not be read or file does not exist
 extos.stat(
   filename       -- path to a file on the file system
 )
 
-Return information on a file. The returned table contains the following fields:
+Return information on a file, following symbolic links if applicable. See also: extos.lstat(...) and extos.fstat(...).
+
+The returned table contains the following fields:
 
 - "dev" (numeric ID of the device containing the file)
 - "ino" (file's inode number)
@@ -48,7 +65,9 @@
 - "isreg" (true if regular file)
 - "issock" (true if socket)
 
-On error, nil and an error message are returned.
+If the file does not exist, false and an error message are returned.
+In case of any other error, nil and an error message are returned.
+
 
 --]]--
 -- implemented in extos.c as
@@ -57,17 +76,36 @@
 
 
 --[[--
-directory_entries,  -- table of directory entries
-errmsg =            -- error message if directory could not be read
-extos.listdir(
-  path              -- path name
+filestat_table,  -- table with information on the file, false if file does not exist, nil on error
+errmsg =         -- error message if file information could not be read or file does not exist
+extos.lstat(
+  filename       -- path to a file on the file system
 )
 
-This function returns a table containing strings representing each entry in a directory. On error nil and an error message are returned.
+Return information on a file. Symbolic links are not followed, which means that if the filename points to a symbolic link, information on that symbolic link will be returned. Otherwise this function behaves like extos.stat(filename).
+
+See extos.stat(...) for further information.
 
 --]]--
 -- implemented in extos.c as
--- static int extos_listdir(lua_State *L)
+-- static int extos_stat(lua_State *L)
+--//--
+
+
+--[[--
+filestat_table,  -- table with information on the file, nil on error
+errmsg =         -- error message if file information could not be determined
+extos.fstat(
+  file_handle    -- Lua file handle (e.g. as returned by io.open(...))
+)
+
+Return information on an open file. The file is specified by passing an open file handle to this function. Otherwise this function behaves like extos.stat(...).
+
+See extos.stat(...) for further information.
+
+--]]--
+-- implemented in extos.c as
+-- static int extos_stat(lua_State *L)
 --//--
 
 
diff -r e00d11c12b68 -r b1748c6c3c89 libraries/extos/extos.c
--- a/libraries/extos/extos.c	Thu Mar 26 12:26:00 2015 +0100
+++ b/libraries/extos/extos.c	Thu Mar 26 16:38:30 2015 +0100
@@ -296,16 +296,30 @@
   return 1;
 }
 
-static int extos_stat(lua_State *L) {
-  const char *filename;
+#define EXTOS_STAT_FOLLOW -1
+#define EXTOS_STAT_NOFOLLOW -2
+
+static int extos_stat_impl(lua_State *L, int fd) {
   struct stat sb;
-  filename = luaL_checkstring(L, 1);
-  if (stat(filename, &sb)) {
-    char errmsg[EXTOS_MAX_ERRLEN+1];
-    strerror_r(errno, errmsg, EXTOS_MAX_ERRLEN+1);
-    lua_pushnil(L);
-    lua_pushfstring(L, "Could not get file stats for \"%s\": %s", filename, errmsg);
-    return 2;
+  if (fd < 0) {
+    const char *filename;
+    filename = luaL_checkstring(L, 1);
+    if (fd == EXTOS_STAT_FOLLOW ? stat(filename, &sb) : lstat(filename, &sb)) {
+      char errmsg[EXTOS_MAX_ERRLEN+1];
+      strerror_r(errno, errmsg, EXTOS_MAX_ERRLEN+1);
+      if (errno == ENOENT) lua_pushboolean(L, 0);
+      else lua_pushnil(L);
+      lua_pushfstring(L, "Could not get file stats for \"%s\": %s", filename, errmsg);
+      return 2;
+    }
+  } else {
+    if (fstat(fd, &sb)) {
+      char errmsg[EXTOS_MAX_ERRLEN+1];
+      strerror_r(errno, errmsg, EXTOS_MAX_ERRLEN+1);
+      lua_pushnil(L);
+      lua_pushfstring(L, "Could not get file stats for open file: %s", errmsg);
+      return 2;
+    }
   }
   lua_createtable(L, 0, 19);
   lua_pushinteger(L, sb.st_dev);
@@ -349,6 +363,21 @@
   return 1;
 }
 
+static int extos_stat(lua_State *L) {
+  return extos_stat_impl(L, EXTOS_STAT_FOLLOW);
+}
+
+static int extos_lstat(lua_State *L) {
+  return extos_stat_impl(L, EXTOS_STAT_NOFOLLOW);
+}
+
+static int extos_fstat(lua_State *L) {
+  luaL_Stream *stream;
+  stream = luaL_checkudata(L, 1, LUA_FILEHANDLE);
+  if (!stream->closef) luaL_error(L, "attempt to use a closed file");
+  return extos_stat_impl(L, fileno(stream->f));
+}
+
 static int extos_crypt(lua_State *L) {
   const char *key;
   const char *salt;
@@ -386,6 +415,8 @@
   {"pfilter",              extos_pfilter},
   {"listdir",              extos_listdir},
   {"stat",                 extos_stat},
+  {"lstat",                extos_lstat},
+  {"fstat",                extos_fstat},
   {"crypt",                extos_crypt},
   {"hires_time",           extos_hires_time},
   {"monotonic_hires_time", extos_monotonic_hires_time},