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kc3-lang/automake/lib/Automake/FileUtils.pm

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  • Author : Alexandre Duret-Lutz
    Date : 2005-05-14 20:28:56
    Hash : 1183efd3
    Message : * COPYING, ChangeLog, ChangeLog.00, ChangeLog.01, ChangeLog.02, ChangeLog.03, ChangeLog.96, ChangeLog.98, HACKING, Makefile.am, NEWS, README, TODO, aclocal.in, automake.in, bootstrap, configure, configure.ac, doc/Makefile.am, doc/fdl.texi, lib/COPYING, lib/Makefile.am, lib/acinstall, lib/compile, lib/config-ml.in, lib/config.guess, lib/config.sub, lib/depcomp, lib/elisp-comp, lib/gnupload, lib/mdate-sh, lib/missing, lib/py-compile, lib/symlink-tree, lib/texinfo.tex, lib/ylwrap, lib/Automake/ChannelDefs.pm, lib/Automake/Channels.pm, lib/Automake/Condition.pm, lib/Automake/Config.in, lib/Automake/Configure_ac.pm, lib/Automake/DisjConditions.pm, lib/Automake/FileUtils.pm, lib/Automake/General.pm, lib/Automake/Item.pm, lib/Automake/ItemDef.pm, lib/Automake/Location.pm, lib/Automake/Makefile.am, lib/Automake/Options.pm, lib/Automake/Rule.pm, lib/Automake/RuleDef.pm, lib/Automake/Struct.pm, lib/Automake/VarDef.pm, lib/Automake/Variable.pm, lib/Automake/Version.pm, lib/Automake/Wrap.pm, lib/Automake/XFile.pm, lib/Automake/tests/Condition.pl, lib/Automake/tests/DisjConditions.pl, lib/Automake/tests/Makefile.am, lib/Automake/tests/Version.pl, lib/Automake/tests/Wrap.pl, lib/am/Makefile.am, lib/am/ansi2knr.am, lib/am/check.am, lib/am/clean-hdr.am, lib/am/clean.am, lib/am/compile.am, lib/am/configure.am, lib/am/data.am, lib/am/dejagnu.am, lib/am/depend.am, lib/am/depend2.am, lib/am/distdir.am, lib/am/footer.am, lib/am/header-vars.am, lib/am/header.am, lib/am/inst-vars.am, lib/am/install.am, lib/am/java.am, lib/am/lang-compile.am, lib/am/lex.am, lib/am/library.am, lib/am/libs.am, lib/am/libtool.am, lib/am/lisp.am, lib/am/ltlib.am, lib/am/ltlibrary.am, lib/am/mans-vars.am, lib/am/mans.am, lib/am/multilib.am, lib/am/program.am, lib/am/progs.am, lib/am/python.am, lib/am/remake-hdr.am, lib/am/scripts.am, lib/am/subdirs.am, lib/am/tags.am, lib/am/texi-vers.am, lib/am/texibuild.am, lib/am/texinfos.am, lib/am/yacc.am, m4/Makefile.am, tests/aclibobj.test, tests/acloca10.test, tests/acloca11.test, tests/acloca12.test, tests/acloca13.test, tests/acloca14.test, tests/acloca15.test, tests/acloca16.test, tests/acloca17.test, tests/acloca18.test, tests/acloca19.test, tests/aclocal.test, tests/aclocal3.test, tests/aclocal4.test, tests/aclocal5.test, tests/aclocal6.test, tests/aclocal7.test, tests/aclocal8.test, tests/aclocal9.test, tests/acoutbs.test, tests/acoutbs2.test, tests/acoutnoq.test, tests/acoutpt.test, tests/acoutpt2.test, tests/acoutqnl.test, tests/acsilent.test, tests/acsubst.test, tests/acsubst2.test, tests/all.test, tests/alloca.test, tests/alloca2.test, tests/alpha.test, tests/alpha2.test, tests/amassign.test, tests/ammissing.test, tests/ansi.test, tests/ansi10.test, tests/ansi2.test, tests/ansi3.test, tests/ansi3b.test, tests/ansi4.test, tests/ansi5.test, tests/ansi6.test, tests/ansi7.test, tests/ansi8.test, tests/ansi9.test, tests/ar.test, tests/ar2.test, tests/asm.test, tests/autohdr.test, tests/autohdr2.test, tests/autohdr3.test, tests/autohdr4.test, tests/automake.test, tests/auxdir.test, tests/auxdir2.test, tests/auxdir3.test, tests/auxdir4.test, tests/backsl.test, tests/backsl2.test, tests/backsl3.test, tests/backsl4.test, tests/badline.test, tests/badopt.test, tests/badprog.test, tests/block.test, tests/bsource.test, tests/canon.test, tests/canon2.test, tests/canon3.test, tests/canon4.test, tests/canon5.test, tests/ccnoco.test, tests/check.test, tests/check2.test, tests/check3.test, tests/check4.test, tests/checkall.test, tests/clean.test, tests/clean2.test, tests/colneq.test, tests/colneq2.test, tests/colon.test, tests/colon2.test, tests/colon3.test, tests/colon4.test, tests/colon5.test, tests/colon6.test, tests/colon7.test, tests/comment.test, tests/comment2.test, tests/comment3.test, tests/comment4.test, tests/comment5.test, tests/comment6.test, tests/comment7.test, tests/comment8.test, tests/comment9.test, tests/compile.test, tests/compile_f90_c_cxx.test, tests/compile_f_c_cxx.test, tests/cond.test, tests/cond10.test, tests/cond11.test, tests/cond13.test, tests/cond14.test, tests/cond15.test, tests/cond16.test, tests/cond17.test, tests/cond18.test, tests/cond19.test, tests/cond2.test, tests/cond20.test, tests/cond21.test, tests/cond22.test, tests/cond23.test, tests/cond24.test, tests/cond25.test, tests/cond26.test, tests/cond27.test, tests/cond28.test, tests/cond29.test, tests/cond3.test, tests/cond30.test, tests/cond31.test, tests/cond32.test, tests/cond33.test, tests/cond34.test, tests/cond35.test, tests/cond36.test, tests/cond37.test, tests/cond4.test, tests/cond5.test, tests/cond6.test, tests/cond7.test, tests/cond8.test, tests/cond9.test, tests/condd.test, tests/condhook.test, tests/condinc.test, tests/condinc2.test, tests/condlib.test, tests/condman.test, tests/condman2.test, tests/conf2.test, tests/confdeps.test, tests/conff.test, tests/conff2.test, tests/confh.test, tests/confh4.test, tests/confh5.test, tests/config.test, tests/confincl.test, tests/conflnk.test, tests/conflnk2.test, tests/conflnk3.test, tests/confsub.test, tests/confvar.test, tests/confvar2.test, tests/copy.test, tests/ctarget1.test, tests/cxx.test, tests/cxx2.test, tests/cxxansi.test, tests/cxxcpp.test, tests/cxxlibobj.test, tests/cxxlink.test, tests/cxxnoc.test, tests/cxxo.test, tests/cygwin32.test, tests/dash.test, tests/defs.in, tests/defun.test, tests/defun2.test, tests/dejagnu.test, tests/dejagnu2.test, tests/dejagnu3.test, tests/dejagnu4.test, tests/dejagnu5.test, tests/dejagnu6.test, tests/dejagnu7.test, tests/depacl2.test, tests/depcomp.test, tests/depcomp2.test, tests/depcomp3.test, tests/depcomp4.test, tests/depcomp5.test, tests/depdist.test, tests/depend.test, tests/depend2.test, tests/depend3.test, tests/depend4.test, tests/destdir.test, tests/dirforbid.test, tests/dirlist.test, tests/discover.test, tests/distcom2.test, tests/distcom3.test, tests/distcom4.test, tests/distcom5.test, tests/distcom6.test, tests/distcom7.test, tests/distdir.test, tests/distname.test, tests/dollar.test, tests/double.test, tests/dup2.test, tests/else.test, tests/empty.test, tests/empty2.test, tests/empty3.test, tests/empty4.test, tests/exdir.test, tests/exdir2.test, tests/exeext.test, tests/exeext2.test, tests/exeext3.test, tests/exeext4.test, tests/exsource.test, tests/ext.test, tests/ext2.test, tests/extra.test, tests/extra2.test, tests/extra3.test, tests/extra4.test, tests/extra5.test, tests/extra6.test, tests/extra7.test, tests/f90only.test, tests/flibs.test, tests/fn99.test, tests/fnoc.test, tests/fo.test, tests/fonly.test, tests/fortdep.test, tests/fpinst2.test, tests/fpinstall.test, tests/gcj.test, tests/gcj2.test, tests/gcj3.test, tests/gcj4.test, tests/gcj5.test, tests/getopt.test, tests/gettext.test, tests/gettext2.test, tests/gnits.test, tests/gnits2.test, tests/gnits3.test, tests/gnumake.test, tests/gnuwarn.test, tests/gnuwarn2.test, tests/header.test, tests/help.test, tests/hfs.test, tests/hosts.test, tests/implicit.test, tests/include.test, tests/include2.test, tests/info.test, tests/insh2.test, tests/install2.test, tests/installdir.test, tests/instdat.test, tests/instdat2.test, tests/instexec.test, tests/insthook.test, tests/instman.test, tests/instman2.test, tests/instsh.test, tests/instsh2.test, tests/instspc.test, tests/interp.test, tests/interp2.test, tests/java.test, tests/java2.test, tests/java3.test, tests/javaprim.test, tests/javasubst.test, tests/ldadd.test, tests/ldflags.test, tests/lex.test, tests/lex2.test, tests/lex3.test, tests/lex4.test, tests/lex5.test, tests/libobj10.test, tests/libobj11.test, tests/libobj12.test, tests/libobj13.test, tests/libobj14.test, tests/libobj2.test, tests/libobj3.test, tests/libobj4.test, tests/libobj5.test, tests/libobj7.test, tests/libobj8.test, tests/library.test, tests/library2.test, tests/library3.test, tests/libtool.test, tests/libtool2.test, tests/libtool3.test, tests/libtool4.test, tests/libtool5.test, tests/libtool6.test, tests/libtool7.test, tests/libtool8.test, tests/libtool9.test, tests/license.test, tests/link_c_cxx.test, tests/link_dist.test, tests/link_f90_only.test, tests/link_f_only.test, tests/link_fc.test, tests/link_fccxx.test, tests/link_fcxx.test, tests/lisp2.test, tests/lisp3.test, tests/lisp4.test, tests/lisp5.test, tests/lisp6.test, tests/lisp7.test, tests/lisp8.test, tests/listval.test, tests/location.test, tests/longlin2.test, tests/longline.test, tests/ltcond.test, tests/ltcond2.test, tests/ltconv.test, tests/ltdeps.test, tests/ltlibobjs.test, tests/ltlibsrc.test, tests/maintclean.test, tests/make.test, tests/makej.test, tests/makevars.test, tests/man.test, tests/man2.test, tests/mclean.test, tests/mdate.test, tests/mdate2.test, tests/mdate3.test, tests/mdate4.test, tests/missing.test, tests/missing2.test, tests/missing3.test, tests/mkinst2.test, tests/mkinstall.test, tests/mmodely.test, tests/multlib.test, tests/nobase.test, tests/nodef.test, tests/nodef2.test, tests/nodep.test, tests/nodepcomp.test, tests/nodist.test, tests/nodist2.test, tests/nodist3.test, tests/nogzip.test, tests/nogzip2.test, tests/noinst.test, tests/noinstdir.test, tests/nolink.test, tests/nostdinc.test, tests/number.test, tests/obsolete.test, tests/order.test, tests/outdir.test, tests/output.test, tests/output10.test, tests/output11.test, tests/output12.test, tests/output2.test, tests/output3.test, tests/output4.test, tests/output5.test, tests/output6.test, tests/output7.test, tests/output8.test, tests/output9.test, tests/overrid.test, tests/parse.test, tests/percent.test, tests/percent2.test, tests/phony.test, tests/pluseq.test, tests/pluseq10.test, tests/pluseq2.test, tests/pluseq3.test, tests/pluseq4.test, tests/pluseq5.test, tests/pluseq6.test, tests/pluseq7.test, tests/pluseq8.test, tests/pluseq9.test, tests/postproc.test, tests/ppf77.test, tests/pr2.test, tests/pr204.test, tests/pr211.test, tests/pr220.test, tests/pr224.test, tests/pr229.test, tests/pr243.test, tests/pr266.test, tests/pr279-2.test, tests/pr279.test, tests/pr287.test, tests/pr300-lib.test, tests/pr300-ltlib.test, tests/pr300-prog.test, tests/pr307.test, tests/pr401.test, tests/pr401b.test, tests/pr401c.test, tests/pr72.test, tests/pr87.test, tests/pr9.test, tests/prefix.test, tests/primary.test, tests/primary2.test, tests/primary3.test, tests/proginst.test, tests/python.test, tests/python10.test, tests/python11.test, tests/python12.test, tests/python2.test, tests/python3.test, tests/python4.test, tests/python5.test, tests/python6.test, tests/python7.test, tests/python8.test, tests/python9.test, tests/recurs.test, tests/recurs2.test, tests/regex.test, tests/remake.test, tests/remake2.test, tests/remake3.test, tests/remake4.test, tests/remake5.test, tests/req.test, tests/reqd.test, tests/reqd2.test, tests/rulepat.test, tests/scripts.test, tests/seenc.test, tests/sinclude.test, tests/space.test, tests/specflg.test, tests/specflg2.test, tests/specflg3.test, tests/specflg6.test, tests/specflg7.test, tests/specflg8.test, tests/specflg9.test, tests/spell.test, tests/spell2.test, tests/spell3.test, tests/spelling.test, tests/spy.test, tests/srcsub.test, tests/srcsub2.test, tests/stamph2.test, tests/stdlib.test, tests/stdlib2.test, tests/strip.test, tests/subcond.test, tests/subcond2.test, tests/subcond3.test, tests/subdir.test, tests/subdir2.test, tests/subdir3.test, tests/subdir4.test, tests/subdir5.test, tests/subdir6.test, tests/subdir7.test, tests/subdir8.test, tests/subdir9.test, tests/subdirbuiltsources.test, tests/subobj.test, tests/subobj2.test, tests/subobj3.test, tests/subobj4.test, tests/subobj5.test, tests/subobj6.test, tests/subobj7.test, tests/subobj8.test, tests/subobj9.test, tests/subobjname.test, tests/subpkg.test, tests/subpkg2.test, tests/subst.test, tests/subst2.test, tests/substre2.test, tests/substref.test, tests/substtarg.test, tests/suffix.test, tests/suffix10.test, tests/suffix11.test, tests/suffix2.test, tests/suffix3.test, tests/suffix4.test, tests/suffix5.test, tests/suffix6.test, tests/suffix7.test, tests/suffix8.test, tests/suffix9.test, tests/symlink.test, tests/symlink2.test, tests/symlink3.test, tests/syntax.test, tests/tags.test, tests/tagsub.test, tests/tar.test, tests/tar2.test, tests/tar3.test, tests/target-cflags.test, tests/targetclash.test, tests/transform.test, tests/txinfo.test, tests/txinfo10.test, tests/txinfo13.test, tests/txinfo16.test, tests/txinfo17.test, tests/txinfo18.test, tests/txinfo19.test, tests/txinfo2.test, tests/txinfo20.test, tests/txinfo21.test, tests/txinfo22.test, tests/txinfo23.test, tests/txinfo24.test, tests/txinfo25.test, tests/txinfo26.test, tests/txinfo27.test, tests/txinfo28.test, tests/txinfo29.test, tests/txinfo3.test, tests/txinfo4.test, tests/txinfo5.test, tests/txinfo6.test, tests/txinfo7.test, tests/txinfo8.test, tests/txinfo9.test, tests/unused.test, tests/vars.test, tests/vars3.test, tests/vartar.test, tests/version.test, tests/version2.test, tests/version3.test, tests/version4.test, tests/version6.test, tests/version7.test, tests/version8.test, tests/vpath.test, tests/vtexi.test, tests/vtexi2.test, tests/warnopts.test, tests/werror.test, tests/werror2.test, tests/whoami.test, tests/xsource.test, tests/yacc.test, tests/yacc2.test, tests/yacc3.test, tests/yacc4.test, tests/yacc5.test, tests/yacc6.test, tests/yacc7.test, tests/yacc8.test, tests/yaccpp.test, tests/yaccvpath.test: Update FSF postal mail address.

  • lib/Automake/FileUtils.pm
  • # Copyright (C) 2003, 2004, 2005  Free Software Foundation, Inc.
    
    # This program is free software; you can redistribute it and/or modify
    # it under the terms of the GNU General Public License as published by
    # the Free Software Foundation; either version 2, or (at your option)
    # any later version.
    
    # This program is distributed in the hope that it will be useful,
    # but WITHOUT ANY WARRANTY; without even the implied warranty of
    # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    # GNU General Public License for more details.
    
    # You should have received a copy of the GNU General Public License
    # along with this program; if not, write to the Free Software
    # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    # 02110-1301, USA.
    
    package Automake::FileUtils;
    
    =head1 NAME
    
    Automake::FileUtils - handling files
    
    =head1 SYNOPSIS
    
      use Automake::FileUtils
    
    =head1 DESCRIPTION
    
    This perl module provides various general purpose file handling functions.
    
    =cut
    
    use strict;
    use Exporter;
    use File::stat;
    use IO::File;
    use Automake::Channels;
    use Automake::ChannelDefs;
    
    use vars qw (@ISA @EXPORT);
    
    @ISA = qw (Exporter);
    @EXPORT = qw (&contents
    	      &find_file &mtime
    	      &update_file &up_to_date_p
    	      &xsystem &xqx &dir_has_case_matching_file &reset_dir_cache);
    
    
    =item C<find_file ($file_name, @include)>
    
    Return the first path for a C<$file_name> in the C<include>s.
    
    We match exactly the behavior of GNU M4: first look in the current
    directory (which includes the case of absolute file names), and, if
    the file is not absolute, just fail.  Otherwise, look in C<@include>.
    
    If the file is flagged as optional (ends with C<?>), then return undef
    if absent, otherwise exit with error.
    
    =cut
    
    # $FILE_NAME
    # find_file ($FILE_NAME, @INCLUDE)
    # -------------------------------
    sub find_file ($@)
    {
      use File::Spec;
    
      my ($file_name, @include) = @_;
      my $optional = 0;
    
      $optional = 1
        if $file_name =~ s/\?$//;
    
      return File::Spec->canonpath ($file_name)
        if -e $file_name;
    
      if (File::Spec->file_name_is_absolute ($file_name))
        {
          fatal "$file_name: no such file or directory"
    	unless $optional;
          return undef;
        }
    
      foreach my $path (@include)
        {
          return File::Spec->canonpath (File::Spec->catfile ($path, $file_name))
    	if -e File::Spec->catfile ($path, $file_name)
        }
    
      fatal "$file_name: no such file or directory"
        unless $optional;
    
      return undef;
    }
    
    =item C<mtime ($file)>
    
    Return the mtime of C<$file>.  Missing files, or C<-> standing for
    C<STDIN> or C<STDOUT> are ``obsolete'', i.e., as old as possible.
    
    =cut
    
    # $MTIME
    # MTIME ($FILE)
    # -------------
    sub mtime ($)
    {
      my ($file) = @_;
    
      return 0
        if $file eq '-' || ! -f $file;
    
      my $stat = stat ($file)
        or fatal "cannot stat $file: $!";
    
      return $stat->mtime;
    }
    
    
    =item C<update_file ($from, $to, [$force])>
    
    Rename C<$from> as C<$to>, preserving C<$to> timestamp if it has not
    changed, unless C<$force> is true (defaults to false).  Recognize
    C<$to> = C<-> standing for C<STDIN>.  C<$from> is always
    removed/renamed.
    
    =cut
    
    # &update_file ($FROM, $TO; $FORCE)
    # ---------------------------------
    sub update_file ($$;$)
    {
      my ($from, $to, $force) = @_;
      $force = 0
        unless defined $force;
      my $SIMPLE_BACKUP_SUFFIX = $ENV{'SIMPLE_BACKUP_SUFFIX'} || '~';
      use File::Compare;
      use File::Copy;
    
      if ($to eq '-')
        {
          my $in = new IO::File ("$from");
          my $out = new IO::File (">-");
          while ($_ = $in->getline)
    	{
    	  print $out $_;
    	}
          $in->close;
          unlink ($from) || fatal "cannot remove $from: $!";
          return;
        }
    
      if (!$force && -f "$to" && compare ("$from", "$to") == 0)
        {
          # File didn't change, so don't update its mod time.
          msg 'note', "`$to' is unchanged";
          unlink ($from)
            or fatal "cannot remove $from: $!";
          return
        }
    
      if (-f "$to")
        {
          # Back up and install the new one.
          move ("$to",  "$to$SIMPLE_BACKUP_SUFFIX")
    	or fatal "cannot backup $to: $!";
          move ("$from", "$to")
    	or fatal "cannot rename $from as $to: $!";
          msg 'note', "`$to' is updated";
        }
      else
        {
          move ("$from", "$to")
    	or fatal "cannot rename $from as $to: $!";
          msg 'note', "`$to' is created";
        }
    }
    
    
    =item C<up_to_date_p ($file, @dep)>
    
    Is C<$file> more recent than C<@dep>?
    
    =cut
    
    # $BOOLEAN
    # &up_to_date_p ($FILE, @DEP)
    # ---------------------------
    sub up_to_date_p ($@)
    {
      my ($file, @dep) = @_;
      my $mtime = mtime ($file);
    
      foreach my $dep (@dep)
        {
          if ($mtime < mtime ($dep))
    	{
    	  verb "up_to_date ($file): outdated: $dep";
    	  return 0;
    	}
        }
    
      verb "up_to_date ($file): up to date";
      return 1;
    }
    
    
    =item C<handle_exec_errors ($command, [$expected_exit_code = 0])>
    
    Display an error message for C<$command>, based on the content of
    C<$?> and C<$!>.  Be quiet if the command exited normally
    with C<$expected_exit_code>.
    
    =cut
    
    sub handle_exec_errors ($;$)
    {
      my ($command, $expected) = @_;
      $expected = 0 unless defined $expected;
    
      $command = (split (' ', $command))[0];
      if ($!)
        {
          fatal "failed to run $command: $!";
        }
      else
        {
          use POSIX qw (WIFEXITED WEXITSTATUS WIFSIGNALED WTERMSIG);
    
          if (WIFEXITED ($?))
    	{
    	  my $status = WEXITSTATUS ($?);
    	  # Propagate exit codes.
    	  fatal ('',
    		 "$command failed with exit status: $status",
    		 exit_code => $status)
    	    unless $status == $expected;
    	}
          elsif (WIFSIGNALED ($?))
    	{
    	  my $signal = WTERMSIG ($?);
    	  fatal "$command terminated by signal: $signal";
    	}
          else
    	{
    	  fatal "$command exited abnormally";
    	}
        }
    }
    
    =item C<xqx ($command)>
    
    Same as C<qx> (but in scalar context), but fails on errors.
    
    =cut
    
    # xqx ($COMMAND)
    # --------------
    sub xqx ($)
    {
      my ($command) = @_;
    
      verb "running: $command";
    
      $! = 0;
      my $res = `$command`;
      handle_exec_errors $command
        if $?;
    
      return $res;
    }
    
    
    =item C<xsystem (@argv)>
    
    Same as C<system>, but fails on errors, and reports the C<@argv>
    in verbose mode.
    
    =cut
    
    sub xsystem (@)
    {
      my (@command) = @_;
    
      verb "running: @command";
    
      $! = 0;
      handle_exec_errors "@command"
        if system @command;
    }
    
    
    =item C<contents ($file_name)>
    
    Return the contents of C<$file_name>.
    
    =cut
    
    # contents ($FILE_NAME)
    # ---------------------
    sub contents ($)
    {
      my ($file) = @_;
      verb "reading $file";
      local $/;			# Turn on slurp-mode.
      my $f = new Automake::XFile "< $file";
      my $contents = $f->getline;
      $f->close;
      return $contents;
    }
    
    
    =item C<dir_has_case_matching_file ($DIRNAME, $FILE_NAME)>
    
    Return true iff $DIR contains a file name that matches $FILE_NAME case
    insensitively.
    
    We need to be cautious on case-insensitive case-preserving file
    systems (e.g. Mac OS X's HFS+).  On such systems C<-f 'Foo'> and C<-f
    'foO'> answer the same thing.  Hence if a package distributes its own
    F<CHANGELOG> file, but has no F<ChangeLog> file, automake would still
    try to distribute F<ChangeLog> (because it thinks it exists) in
    addition to F<CHANGELOG>, although it is impossible for these two
    files to be in the same directory (the two file names designate the
    same file).
    
    =cut
    
    use vars '%_directory_cache';
    sub dir_has_case_matching_file ($$)
    {
      # Note that print File::Spec->case_tolerant returns 0 even on MacOS
      # X (with Perl v5.8.1-RC3 at least), so do not try to shortcut this
      # function using that.
    
      my ($dirname, $file_name) = @_;
      return 0 unless -f "$dirname/$file_name";
    
      # The file appears to exist, however it might be a mirage if the
      # system is case insensitive.  Let's browse the directory and check
      # whether the file is really in.  We maintain a cache of directories
      # so Automake doesn't spend all its time reading the same directory
      # again and again.
      if (!exists $_directory_cache{$dirname})
        {
          error "failed to open directory `$dirname'"
    	unless opendir (DIR, $dirname);
          $_directory_cache{$dirname} = { map { $_ => 1 } readdir (DIR) };
          closedir (DIR);
        }
      return exists $_directory_cache{$dirname}{$file_name};
    }
    
    =item C<reset_dir_cache ($dirname)>
    
    Clear C<dir_has_case_matching_file>'s cache for C<$dirname>.
    
    =cut
    
    sub reset_dir_cache ($)
    {
      delete $_directory_cache{$_[0]};
    }
    
    1; # for require
    
    ### Setup "GNU" style for perl-mode and cperl-mode.
    ## Local Variables:
    ## perl-indent-level: 2
    ## perl-continued-statement-offset: 2
    ## perl-continued-brace-offset: 0
    ## perl-brace-offset: 0
    ## perl-brace-imaginary-offset: 0
    ## perl-label-offset: -2
    ## cperl-indent-level: 2
    ## cperl-brace-offset: 0
    ## cperl-continued-brace-offset: 0
    ## cperl-label-offset: -2
    ## cperl-extra-newline-before-brace: t
    ## cperl-merge-trailing-else: nil
    ## cperl-continued-statement-offset: 2
    ## End: