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emacs/m4/dirent_h.m4
Paul Eggert 8654f9d7d6 Use fdopendir, fstatat and readlinkat, for efficiency.
On my host, this speeds up directory-files-and-attributes by a
factor of 3, when applied to Emacs's src directory.
These functions are standardized by POSIX and are common these
days; fall back on a (slower) gnulib implementation if the host
is too old to supply them.
* .bzrignore: Add lib/dirent.h.
* lib/Makefile.am (libgnu_a_SOURCES): Add openat-die.c, save-cwd.c.
* lib/careadlinkat.c, lib/careadlinkat.h: Merge from gnulib,
incorporating: 2013-01-29 careadlinkat: do not provide careadlinkatcwd.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/dirent.in.h, lib/fdopendir.c, lib/fstatat.c, lib/openat-priv.h:
* lib/openat-proc.c, lib/openat.h, m4/dirent_h.m4, m4/fdopendir.m4:
* m4/fstatat.m4: New files, from gnulib.
* lib/openat-die.c, lib/save-cwd.c, lib/save-cwd.h: New files.
These last three are specific to Emacs and are not copied from gnulib.
They are simpler than the gnulib versions and are tuned for Emacs.
* admin/merge-gnulib (GNULIB_MODULES): Add fdopendir, fstatat, readlinkat.
(GNULIB_TOOL_FLAGS): Do not avoid at-internal, openat-h.
Avoid dup, open, opendir.
* nt/inc/sys/stat.h (fstatat):
* nt/inc/unistd.h (readlinkat): New decls.
* src/conf_post.h (GNULIB_SUPPORT_ONLY_AT_FDCWD): Remove.
* src/dired.c: Include <fcntl.h>.
(open_directory): New function, which uses open and fdopendir
rather than opendir.  DOS_NT platforms still use opendir, though.
(directory_files_internal, file_name_completion): Use it.
(file_attributes): New function, with most of the old Ffile_attributes.
(directory_files_internal, Ffile_attributes): Use it.
(file_attributes, file_name_completion_stat): First arg is now fd,
not dir name.  All uses changed.  Use fstatat rather than lstat +
stat.
(file_attributes): Use emacs_readlinkat rather than Ffile_symlink_p.
* src/fileio.c: Include <allocator.h>, <careadlinkat.h>.
(emacs_readlinkat): New function, with much of the old
Ffile_symlink_p, but with an fd argument for speed.
It uses readlinkat rather than careadlinkatcwd, so that it
need not assume the working directory.
(Ffile_symlink_p): Use it.
* src/filelock.c (current_lock_owner): Use emacs_readlinkat
rather than emacs_readlink.
* src/lisp.h (emacs_readlinkat): New decl.
(READLINK_BUFSIZE, emacs_readlink): Remove.
* src/sysdep.c: Do not include <allocator.h>, <careadlinkat.h>.
(emacs_norealloc_allocator, emacs_readlink): Remove.
This stuff is moved to fileio.c.
* src/w32.c (fstatat, readlinkat): New functions.
(careadlinkat): Don't check that fd == AT_FDCWD.
(careadlinkatcwd): Remove; no longer needed.

Fixes: debbugs:13539
2013-01-31 22:30:51 -08:00

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# dirent_h.m4 serial 16
dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Written by Bruno Haible.
AC_DEFUN([gl_DIRENT_H],
[
dnl Use AC_REQUIRE here, so that the default behavior below is expanded
dnl once only, before all statements that occur in other macros.
AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
dnl <dirent.h> is always overridden, because of GNULIB_POSIXCHECK.
gl_CHECK_NEXT_HEADERS([dirent.h])
if test $ac_cv_header_dirent_h = yes; then
HAVE_DIRENT_H=1
else
HAVE_DIRENT_H=0
fi
AC_SUBST([HAVE_DIRENT_H])
dnl Check for declarations of anything we want to poison if the
dnl corresponding gnulib module is not in use.
gl_WARN_ON_USE_PREPARE([[#include <dirent.h>
]], [alphasort closedir dirfd fdopendir opendir readdir rewinddir scandir])
])
AC_DEFUN([gl_DIRENT_MODULE_INDICATOR],
[
dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
gl_MODULE_INDICATOR_SET_VARIABLE([$1])
dnl Define it also as a C macro, for the benefit of the unit tests.
gl_MODULE_INDICATOR_FOR_TESTS([$1])
])
AC_DEFUN([gl_DIRENT_H_DEFAULTS],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) dnl for REPLACE_FCHDIR
GNULIB_OPENDIR=0; AC_SUBST([GNULIB_OPENDIR])
GNULIB_READDIR=0; AC_SUBST([GNULIB_READDIR])
GNULIB_REWINDDIR=0; AC_SUBST([GNULIB_REWINDDIR])
GNULIB_CLOSEDIR=0; AC_SUBST([GNULIB_CLOSEDIR])
GNULIB_DIRFD=0; AC_SUBST([GNULIB_DIRFD])
GNULIB_FDOPENDIR=0; AC_SUBST([GNULIB_FDOPENDIR])
GNULIB_SCANDIR=0; AC_SUBST([GNULIB_SCANDIR])
GNULIB_ALPHASORT=0; AC_SUBST([GNULIB_ALPHASORT])
dnl Assume proper GNU behavior unless another module says otherwise.
HAVE_OPENDIR=1; AC_SUBST([HAVE_OPENDIR])
HAVE_READDIR=1; AC_SUBST([HAVE_READDIR])
HAVE_REWINDDIR=1; AC_SUBST([HAVE_REWINDDIR])
HAVE_CLOSEDIR=1; AC_SUBST([HAVE_CLOSEDIR])
HAVE_DECL_DIRFD=1; AC_SUBST([HAVE_DECL_DIRFD])
HAVE_DECL_FDOPENDIR=1;AC_SUBST([HAVE_DECL_FDOPENDIR])
HAVE_FDOPENDIR=1; AC_SUBST([HAVE_FDOPENDIR])
HAVE_SCANDIR=1; AC_SUBST([HAVE_SCANDIR])
HAVE_ALPHASORT=1; AC_SUBST([HAVE_ALPHASORT])
REPLACE_OPENDIR=0; AC_SUBST([REPLACE_OPENDIR])
REPLACE_CLOSEDIR=0; AC_SUBST([REPLACE_CLOSEDIR])
REPLACE_DIRFD=0; AC_SUBST([REPLACE_DIRFD])
REPLACE_FDOPENDIR=0; AC_SUBST([REPLACE_FDOPENDIR])
])