openat: conditional dependencies

[Bruno Haible]

Hi Jim,

Now that the module structure of the *at functions is cleaned up - one
function provided per module (except for mkfifoat and mknodat which can
stay in a single module because they are nearly the same thing) -, let
me try to improve what's built with --conditional-dependencies.

Here's the first proposed patch, for the 'openat' replacement.

The save-cwd code is only needed when $HAVE_OPENAT = 0 (i.e. when the system
does not have openat()), not when $REPLACE_OPENAT = 1 (i.e. when gnulib
overrides the system's openat() function). But the .c file currently includes
save-cwd.h in both cases. Since we cannot include save-cwd.h without having
invoked gl_SAVE_CWD, we need to depend on 'save-cwd' (and thus compile the
code of save-cwd.c) _just_ for the sake of the position of the #include
statement.

Here's the proposed patch. While it is a good general guideline to do all
#includes before all function definitions and all #ifs, I think it's worth
deviating from that practice if it can avoid to compile unused compilation
units.


2011-11-05  Bruno Haible  <address@hidden>

        openat: Conditionalize dependencies.
        * lib/openat.c: Reduce the scope of some #includes.
        * modules/openat (Depends-on): Add conditions.

--- lib/openat.c.orig   Sat Nov  5 11:53:34 2011
+++ lib/openat.c        Sat Nov  5 11:48:57 2011
@@ -47,10 +47,6 @@
 #include <string.h>
 #include <sys/stat.h>
 
-#include "dosname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
-#include "openat-priv.h"
-#include "save-cwd.h"
-
 #if HAVE_OPENAT
 
 /* Like openat, but work around Solaris 9 bugs with trailing slash.  */
@@ -144,6 +140,10 @@
 
 #else /* !HAVE_OPENAT */
 
+# include "dosname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
+# include "openat-priv.h"
+# include "save-cwd.h"
+
 /* Replacement for Solaris' openat function.
    <http://www.google.com/search?q=openat+site:docs.sun.com>
    First, try to simulate it via open ("/proc/self/fd/FD/FILE").
--- modules/openat.orig Sat Nov  5 11:53:34 2011
+++ modules/openat      Sat Nov  5 11:52:40 2011
@@ -9,20 +9,20 @@
 m4/mode_t.m4
 
 Depends-on:
-at-internal
-dosname
-errno
-extensions
-fchdir
 fcntl-h
-fstat
+extensions
 largefile
-open
-openat-die
-openat-h
-save-cwd
-stdbool
-sys_stat
+openat-h        [test $HAVE_OPENAT = 0 || test $REPLACE_OPENAT = 1]
+stdbool         [test $HAVE_OPENAT = 0 || test $REPLACE_OPENAT = 1]
+sys_stat        [test $HAVE_OPENAT = 0 || test $REPLACE_OPENAT = 1]
+fstat           [test $REPLACE_OPENAT = 1]
+at-internal     [test $HAVE_OPENAT = 0]
+dosname         [test $HAVE_OPENAT = 0]
+errno           [test $HAVE_OPENAT = 0]
+fchdir          [test $HAVE_OPENAT = 0]
+open            [test $HAVE_OPENAT = 0]
+openat-die      [test $HAVE_OPENAT = 0]
+save-cwd        [test $HAVE_OPENAT = 0]
 
 configure.ac:
 gl_FUNC_OPENAT
-- 
In memoriam Bernhard Lichtenberg 
<http://en.wikipedia.org/wiki/Bernhard_Lichtenberg>