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8654f9d7d6
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
48 lines
1.9 KiB
C
48 lines
1.9 KiB
C
/* Read a symlink relative to an open directory.
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Copyright (C) 2009-2013 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* written by Eric Blake */
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#include <config.h>
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#include <unistd.h>
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/* Gnulib provides a readlink stub for mingw; use it for distinction
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between EINVAL and ENOENT, rather than always failing with ENOSYS. */
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/* POSIX 2008 says that unlike readlink, readlinkat returns 0 for
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success instead of the buffer length. But this would render
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readlinkat worthless since readlink does not guarantee a
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NUL-terminated buffer. Assume this was a bug in POSIX. */
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/* Read the contents of symlink FILE into buffer BUF of size LEN, in the
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directory open on descriptor FD. If possible, do it without changing
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the working directory. Otherwise, resort to using save_cwd/fchdir,
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then readlink/restore_cwd. If either the save_cwd or the restore_cwd
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fails, then give a diagnostic and exit nonzero. */
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#define AT_FUNC_NAME readlinkat
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#define AT_FUNC_F1 readlink
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#define AT_FUNC_POST_FILE_PARAM_DECLS , char *buf, size_t len
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#define AT_FUNC_POST_FILE_ARGS , buf, len
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#define AT_FUNC_RESULT ssize_t
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#include "at-func.c"
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#undef AT_FUNC_NAME
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#undef AT_FUNC_F1
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#undef AT_FUNC_POST_FILE_PARAM_DECLS
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#undef AT_FUNC_POST_FILE_ARGS
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#undef AT_FUNC_RESULT
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