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author | Paul Eggert <eggert@cs.ucla.edu> | 2013-01-31 22:30:51 -0800 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2013-01-31 22:30:51 -0800 |
commit | 8654f9d7d6d7c3ee97232a34a40250dcbc57af8e (patch) | |
tree | ff488081b57dabdfe7e85c11a34e8ac522b5bdb4 /m4/fstatat.m4 | |
parent | 44b12dd6994a6214b9d6f73539b441080611369b (diff) | |
download | emacs-8654f9d7d6d7c3ee97232a34a40250dcbc57af8e.tar.gz |
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
Diffstat (limited to 'm4/fstatat.m4')
-rw-r--r-- | m4/fstatat.m4 | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/m4/fstatat.m4 b/m4/fstatat.m4 new file mode 100644 index 00000000000..adbc7e57f51 --- /dev/null +++ b/m4/fstatat.m4 @@ -0,0 +1,60 @@ +# fstatat.m4 serial 3 +dnl Copyright (C) 2004-2013 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. + +# Written by Jim Meyering. + +# If we have the fstatat function, and it has the bug (in AIX 7.1) +# that it does not fill in st_size correctly, use the replacement function. +AC_DEFUN([gl_FUNC_FSTATAT], +[ + AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS]) + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CHECK_FUNCS_ONCE([fstatat]) + + if test $ac_cv_func_fstatat = no; then + HAVE_FSTATAT=0 + else + dnl Test for an AIX 7.1 bug; see + dnl <http://lists.gnu.org/archive/html/bug-tar/2011-09/msg00015.html>. + AC_CACHE_CHECK([whether fstatat (..., 0) works], + [gl_cv_func_fstatat_zero_flag], + [AC_RUN_IFELSE( + [AC_LANG_SOURCE( + [[ + #include <fcntl.h> + #include <sys/stat.h> + int + main (void) + { + struct stat a; + return fstatat (AT_FDCWD, ".", &a, 0) != 0; + } + ]])], + [gl_cv_func_fstatat_zero_flag=yes], + [gl_cv_func_fstatat_zero_flag=no], + [case "$host_os" in + aix*) gl_cv_func_fstatat_zero_flag="guessing no";; + *) gl_cv_func_fstatat_zero_flag="guessing yes";; + esac + ]) + ]) + + case $gl_cv_func_fstatat_zero_flag+$gl_cv_func_lstat_dereferences_slashed_symlink in + *yes+*yes) ;; + *) REPLACE_FSTATAT=1 + case $gl_cv_func_fstatat_zero_flag in + *yes) + AC_DEFINE([HAVE_WORKING_FSTATAT_ZERO_FLAG], [1], + [Define to 1 if fstatat (..., 0) works. + For example, it does not work in AIX 7.1.]) + ;; + esac + ;; + esac + fi +]) |