Describe the possibility of using comments in configuration files

[devedit.git] / modules / File / Access.pm

diff --git a/modules/File/Access.pm b/modules/File/Access.pm
index 3bfd50db657431210d5560456a6ca246eaea9b4f..70a1c04a33257c53b0f2e9b3c588f202f441d8dd 100644 (file)
--- a/modules/File/Access.pm
+++ b/modules/File/Access.pm
@@ -3,48 +3,40 @@ package File::Access;
 #
 # Dev-Editor - Module File::Access
 #
-# Some simple routines for doing things with files
-# with only one command
+# Some simple routines for doing things with files by
+# using only one command
 #
-# Author:        Patrick Canterino <patshaping@gmx.net>
-# Last modified: 2004-08-05
+# Author:        Patrick Canterino <patrick@patshaping.de>
+# Last modified: 2005-04-09
 #
 
 use strict;
 
-use vars qw(@EXPORT);
+use vars qw(@EXPORT
+            $has_flock);
 
-use Fcntl;
+use Fcntl qw(:DEFAULT
+             :flock);
 
 ### Export ###
 
 use base qw(Exporter);
 
-@EXPORT = qw(chgrp
-             dir_read
+@EXPORT = qw(dir_read
              file_create
+             file_lock
              file_read
              file_save
-             file_unlock);
 
-# chgrp()
-#
-# Change the group of files or directories
-#
-# Params: 1. Group name
-#         2. List of files
-#
-# Return: Number of files group successfully changed
-#         (or false)
+             LOCK_SH
+             LOCK_EX
+             LOCK_UN
+             LOCK_NB);
 
-sub chgrp($@)
-{
- my ($group,@files) = @_;
- my $gid = ($group !~ /^\d+$/) ? getgrnam($group) : $group;
+# Check if flock() is available
+# I found this piece of code somewhere in the internet
 
- return unless($gid);
- return chown(-1,$gid,@files);
-}
+$has_flock = eval { local $SIG{'__DIE__'}; flock(STDOUT,0); 1 };
 
 # dir_read()
 #
@@ -53,7 +45,7 @@ sub chgrp($@)
 # Params: Directory
 #
 # Return: Hash reference: dirs  => directories
-#                         files => files
+#                         files => files and symbolic links
 
 sub dir_read($)
 {
@@ -77,9 +69,9 @@ sub dir_read($)
 
  foreach my $entry(@entries)
  {
-  next if($entry eq "." || $entry eq "..");
+  next if($entry eq '.' || $entry eq '..');
 
-  if(-d $dir."/".$entry)
+  if(-d $dir.'/'.$entry && not -l $dir.'/'.$entry)
   {
    push(@dirs,$entry);
   }
@@ -94,7 +86,11 @@ sub dir_read($)
 
 # file_create()
 #
-# Create a file
+# Create a file, but only if it doesn't already exist
+#
+# (I wanted to use O_EXCL for this, but `perldoc -f sysopen`
+# doesn't say that it is available on every system - so I
+# created this workaround using O_RDONLY and O_CREAT)
 #
 # Params: File to create
 #
@@ -114,21 +110,46 @@ sub file_create($)
  return 1;
 }
 
+# file_lock()
+#
+# System independent wrapper function for flock()
+# On systems where flock() is not available, this function
+# always returns true.
+#
+# Params: 1. Filehandle
+#         2. Locking mode
+#
+# Return: Status code (Boolean)
+
+sub file_lock(*$)
+{
+ my ($handle,$mode) = @_;
+
+ return 1 unless($has_flock);
+ return flock($handle,$mode);
+}
+
 # file_read()
 #
 # Read out a file completely
 #
-# Params: File
+# Params: 1. File
+#         2. true  => open in binary mode
+#            false => open in normal mode (default)
 #
 # Return: Contents of the file (Scalar Reference)
 
-sub file_read($)
+sub file_read($;$)
 {
- my $file = shift;
+ my ($file,$binary) = @_;
  local *FILE;
 
  sysopen(FILE,$file,O_RDONLY) or return;
+ file_lock(FILE,LOCK_SH)      or do { close(FILE); return };
+ binmode(FILE) if($binary);
+
  read(FILE, my $content, -s $file);
+
  close(FILE)                  or return;
 
  return \$content;
@@ -140,40 +161,27 @@ sub file_read($)
 #
 # Params: 1. File
 #         2. File content as Scalar Reference
+#         3. true  => open in binary mode
+#            false => open in normal mode (default)
 #
 # Return: Status code (Boolean)
 
-sub file_save($$)
+sub file_save($$;$)
 {
- my ($file,$content) = @_;
+ my ($file,$content,$binary) = @_;
  local *FILE;
 
  sysopen(FILE,$file,O_WRONLY | O_CREAT | O_TRUNC) or return;
+ file_lock(FILE,LOCK_EX)                          or do { close(FILE); return };
+ binmode(FILE) if($binary);
+
  print FILE $$content                             or do { close(FILE); return };
+
  close(FILE)                                      or return;
 
  return 1;
 }
 
-# file_unlock()
-#
-# Remove a file from the list of files in use
-#
-# Params: 1. File::UseList object
-#         2. File to remove
-#
-# Return: -nothing-
-
-sub file_unlock($$)
-{
- my ($uselist,$file) = @_;
-
- $uselist->remove_file($file);
- $uselist->save;
-
- return;
-}
-
 # it's true, baby ;-)
 
 1;