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# -*- perl -*-
#
# Copyright (C) Heinz-Josef Claes (2000-2012)
# hjclaes@web.de
#
# 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.
#
require 'checkObjPar.pl';
push @VERSION, '$Id: tail.pl 362 2012-01-28 22:11:13Z hjc $ ';
use strict;
######################################################################
# Objekt zum Weiterlesen einer Datei, hierzu ist regelm"a"sig, durch
# sleep unterbrochen, die Methode read aufzurufen
package tailOneFile;
sub new
{
my $class = shift;
my $self = {};
# Defaultwerte f"ur Parameter setzen
my (%params) = ('-filename' => undef,
'-position' => 'begin',# Datei von Anfang an durchsuchen
# kann die Werte 'begin' oder
# 'end' haben
'-prefix' => '', # wird vor jede Zeile geh"angt
'-postfix' => '', # wird an jede Zeile geh"angt
'-maxlines' => undef # maximale Anzahl von Zeilen pro
# Aufruf von read
);
&::checkObjectParams(\%params, \@_, 'tailOneFile::new', ['-filename']);
$self->{'param'} = \%params;
$self->{'filesize'} = 0;
if ($params{'-position'} eq 'begin')
{
$self->{'curpos'} = 0;
$self->{'filehandle'} = undef;
$self->{'openflag'} = 0; # Datei ist nicht ge"offnet
}
elsif ($params{'-position'} eq 'end')
{
local *FILE;
if (open(FILE, $params{'-filename'}))
{
$self->{'openflag'} = 1;
$self->{'filehandle'} = *FILE;
$self->{'curpos'} = (stat FILE)[7];
seek(FILE, $self->{'curpos'}, 0);
}
}
else
{
print STDERR "wrong value for <-position>: must be 'begin' or 'end'\n";
}
bless($self, $class);
}
sub getpar
{
my $self = shift;
my $par = shift;
return $self->{'param'}{$par};
}
sub read
{
my $self = shift;
local *FILE;
my $filename = $self->{'param'}{'-filename'};
my (@lines) = ();
return(\@lines, "no read permissions for <$filename>")
if -e $filename and not -r $filename;
if ($self->{'openflag'} == 0) # Datei "offnen
{
# Datei wurde gel"oscht (oder mv), neue noch
# nicht angelegt, warten.
return \@lines unless (open(FILE, $filename));
$self->{'filehandle'} = *FILE;
$self->{'openflag'} = 1;
}
*FILE = $self->{'filehandle'};
my ($curpos) = $self->{'curpos'};
my ($pre) = $self->{'param'}{'-prefix'};
my ($post) = $self->{'param'}{'-postfix'};
my ($l, $i);
my $max = $self->{'param'}{'-maxlines'};
for ($curpos = tell(FILE), $i = 1 ; $l = <FILE> ;
$curpos = tell(FILE), $i++)
{
chomp $l;
push @lines, "$pre$l$post\n";
last if ($max and $i >= $max);
}
my ($size_old) = $self->{'filesize'};
$self->{'filesize'} = (stat $filename)[7];
if ($self->{'filesize'} < $size_old)
{
close(FILE);
$self->{'openflag'} = 0;
}
else
{
seek(FILE, $curpos, 0); # seek to where we had been
}
$self->{'curpos'} = $curpos;
return (\@lines, undef); # ok
}
sub DESTROY
{
my $self = shift;
local *FILE = $self->{'filehandle'};
close(FILE) or die "cannot close <", $self->{'param'}{'-filename'}, ">\n";
}
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