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use Data::Dumper; |
use Data::Dumper; |
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our $VERSION = '0.03'; |
our $VERSION = '0.06'; |
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=head1 NAME |
=head1 NAME |
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use Fuse::DBI; |
use Fuse::DBI; |
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Fuse::DBI->mount( ... ); |
Fuse::DBI->mount( ... ); |
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See L<run> below for examples how to set parametars. |
See C<run> below for examples how to set parameters. |
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=head1 DESCRIPTION |
=head1 DESCRIPTION |
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This module will use L<Fuse> module, part of C<FUSE (Filesystem in USErspace)> |
This module will use C<Fuse> module, part of C<FUSE (Filesystem in USErspace)> |
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available at L<http://sourceforge.net/projects/avf> to mount |
available at L<http://fuse.sourceforge.net/> to mount |
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your database as file system. |
your database as file system. |
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That will give you posibility to use normal file-system tools (cat, grep, vi) |
That will give you possibility to use normal file-system tools (cat, grep, vi) |
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to manipulate data in database. |
to manipulate data in database. |
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It's actually opposite of Oracle's intention to put everything into database. |
It's actually opposite of Oracle's intention to put everything into database. |
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Mount your database as filesystem. |
Mount your database as filesystem. |
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Let's suppose that your database have table C<files> with following structure: |
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id: int |
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filename: text |
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size: int |
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content: text |
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writable: boolean |
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Following is example how to mount table like that to C</mnt>: |
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my $mnt = Fuse::DBI->mount({ |
my $mnt = Fuse::DBI->mount({ |
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filenames => 'select name from files_table as filenames', |
'filenames' => 'select id,filename,size,writable from files', |
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read => 'sql read', |
'read' => 'select content from files where id = ?', |
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update => 'sql update', |
'update' => 'update files set content = ? where id = ?', |
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dsn => 'DBI:Pg:dbname=webgui', |
'dsn' => 'DBI:Pg:dbname=test_db', |
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user => 'database_user', |
'user' => 'database_user', |
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password => 'database_password' |
'password' => 'database_password', |
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'invalidate' => sub { ... }, |
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}); |
}); |
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Options: |
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=over 5 |
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=item filenames |
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SQL query which returns C<id> (unique id for that row), C<filename>, |
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C<size> and C<writable> boolean flag. |
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=item read |
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SQL query which returns only one column with content of file and has |
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placeholder C<?> for C<id>. |
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=item update |
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SQL query with two pace-holders, one for new content and one for C<id>. |
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=item dsn |
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C<DBI> dsn to connect to (contains database driver and name of database). |
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=item user |
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User with which to connect to database |
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=item password |
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Password for connecting to database |
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=item invalidate |
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Optional anonymous code reference which will be executed when data is updated in |
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database. It can be used as hook to delete cache (for example on-disk-cache) |
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which is created from data edited through C<Fuse::DBI>. |
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=item fork |
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Optional flag which forks after mount so that executing script will continue |
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running. Implementation is experimental. |
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=back |
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=cut |
=cut |
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my $dbh; |
my $dbh; |
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sub read_filenames; |
sub read_filenames; |
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sub fuse_module_loaded; |
sub fuse_module_loaded; |
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# evil, evil way to solve this. It makes this module non-reentrant. But, since |
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# fuse calls another copy of this script for each mount anyway, this shouldn't |
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# be a problem. |
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my $fuse_self; |
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sub mount { |
sub mount { |
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my $class = shift; |
my $class = shift; |
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my $self = {}; |
my $self = {}; |
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carp "mount needs 'mount' as mountpoint" unless ($arg->{'mount'}); |
carp "mount needs 'mount' as mountpoint" unless ($arg->{'mount'}); |
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# save (some) arguments in self |
# save (some) arguments in self |
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$self->{$_} = $arg->{$_} foreach (qw(mount)); |
foreach (qw(mount invalidate)) { |
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$self->{$_} = $arg->{$_}; |
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} |
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foreach (qw(filenames read update)) { |
foreach (qw(filenames read update)) { |
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carp "mount needs '$_' SQL" unless ($arg->{$_}); |
carp "mount needs '$_' SQL" unless ($arg->{$_}); |
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$dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr; |
$dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr; |
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$sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr(); |
$sth->{'filenames'} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr(); |
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$sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr(); |
$sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr(); |
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$sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr(); |
$sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr(); |
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$self->{'sth'} = $sth; |
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$self->{'read_filenames'} = sub { $self->read_filenames }; |
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$self->read_filenames; |
$self->read_filenames; |
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$fuse_self = \$self; |
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Fuse::main( |
Fuse::main( |
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mountpoint=>$arg->{'mount'}, |
mountpoint=>$arg->{'mount'}, |
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getattr=>\&e_getattr, |
getattr=>\&e_getattr, |
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utime=>\&e_utime, |
utime=>\&e_utime, |
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truncate=>\&e_truncate, |
truncate=>\&e_truncate, |
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unlink=>\&e_unlink, |
unlink=>\&e_unlink, |
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rmdir=>\&e_unlink, |
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debug=>0, |
debug=>0, |
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); |
); |
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exit(0) if ($arg->{'fork'}); |
exit(0) if ($arg->{'fork'}); |
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return 1; |
return 1; |
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sub umount { |
sub umount { |
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my $self = shift; |
my $self = shift; |
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system "fusermount -u ".$self->{'mount'} || croak "umount error: $!"; |
if ($self->{'mount'}) { |
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if (open(MTAB, "/etc/mtab")) { |
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my $mounted = 0; |
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my $mount = $self->{'mount'}; |
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while(<MTAB>) { |
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$mounted = 1 if (/ $mount fuse /i); |
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} |
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close(MTAB); |
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if ($mounted) { |
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system "fusermount -u ".$self->{'mount'}." 2>&1 >/dev/null" || return 0; |
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return 1; |
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} |
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} else { |
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warn "can't open /etc/mtab: $!"; |
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return 0; |
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} |
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} |
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} |
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return 1; |
$SIG{'INT'} = sub { |
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if ($fuse_self && $$fuse_self->umount) { |
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print STDERR "umount called by SIG INT\n"; |
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} |
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}; |
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$SIG{'QUIT'} = sub { |
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if ($fuse_self && $$fuse_self->umount) { |
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print STDERR "umount called by SIG QUIT\n"; |
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} |
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}; |
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sub DESTROY { |
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my $self = shift; |
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if ($self->umount) { |
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print STDERR "umount called by DESTROY\n"; |
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} |
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} |
} |
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=head2 fuse_module_loaded |
=head2 fuse_module_loaded |
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die "no fuse module loaded in kernel" |
die "no fuse module loaded in kernel" |
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unless (Fuse::DBI::fuse_module_loaded); |
unless (Fuse::DBI::fuse_module_loaded); |
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This function in called by L<mount>, but might be useful alone also. |
This function in called by C<mount>, but might be useful alone also. |
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=cut |
=cut |
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sub read_filenames { |
sub read_filenames { |
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my $self = shift; |
my $self = shift; |
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my $sth = $self->{'sth'} || die "no sth argument"; |
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# create empty filesystem |
# create empty filesystem |
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(%files) = ( |
(%files) = ( |
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'.' => { |
'.' => { |
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type => 0040, |
type => 0040, |
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mode => 0755, |
mode => 0755, |
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}, |
}, |
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'..' => { |
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type => 0040, |
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mode => 0755, |
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}, |
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# a => { |
# a => { |
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# cont => "File 'a'.\n", |
# cont => "File 'a'.\n", |
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# type => 0100, |
# type => 0100, |
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my %out; |
my %out; |
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foreach my $f (sort keys %files) { |
foreach my $f (sort keys %files) { |
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if ($dirname) { |
if ($dirname) { |
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if ($f =~ s/^\E$dirname\Q\///) { |
if ($f =~ s/^\Q$dirname\E\///) { |
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$out{$f}++ if ($f =~ /^[^\/]+$/); |
$out{$f}++ if ($f =~ /^[^\/]+$/); |
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} |
} |
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} else { |
} else { |
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$sth->{'read'}->execute($id) || die $sth->{'read'}->errstr; |
$sth->{'read'}->execute($id) || die $sth->{'read'}->errstr; |
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$files{$file}{cont} = $sth->{'read'}->fetchrow_array; |
$files{$file}{cont} = $sth->{'read'}->fetchrow_array; |
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# I should modify ctime only if content in database changed |
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#$files{$file}{ctime} = time() unless ($files{$file}{ctime}); |
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print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n"; |
print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n"; |
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} |
} |
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print "invalidate all cached content\n"; |
print "invalidate all cached content\n"; |
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foreach my $f (keys %files) { |
foreach my $f (keys %files) { |
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delete $files{$f}{cont}; |
delete $files{$f}{cont}; |
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delete $files{$f}{ctime}; |
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} |
} |
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print "begin new transaction\n"; |
print "begin new transaction\n"; |
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#$dbh->begin_work || die $dbh->errstr; |
#$dbh->begin_work || die $dbh->errstr; |
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return 0; |
return 0; |
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} |
} |
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print "updated '$file' [",$files{$file}{id},"]\n"; |
print "updated '$file' [",$files{$file}{id},"]\n"; |
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$$fuse_self->{'invalidate'}->() if (ref $$fuse_self->{'invalidate'}); |
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} |
} |
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return 1; |
return 1; |
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} |
} |
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sub e_unlink { |
sub e_unlink { |
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my $file = filename_fixup(shift); |
my $file = filename_fixup(shift); |
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return -ENOENT() unless exists($files{$file}); |
if (exists( $dirs{$file} )) { |
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print "unlink '$file' will re-read template names\n"; |
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print "unlink '$file' will invalidate cache\n"; |
print Dumper($fuse_self); |
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$$fuse_self->{'read_filenames'}->(); |
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read_content($file,$files{$file}{id}); |
return 0; |
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} elsif (exists( $files{$file} )) { |
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print "unlink '$file' will invalidate cache\n"; |
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read_content($file,$files{$file}{id}); |
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return 0; |
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} |
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return 0; |
return -ENOENT(); |
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} |
} |
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1; |
1; |
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__END__ |
__END__ |
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Nothing. |
Nothing. |
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=head1 BUGS |
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Size information (C<ls -s>) is wrong. It's a problem in upstream Fuse module |
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(for which I'm to blame lately), so when it gets fixes, C<Fuse::DBI> will |
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automagically pick it up. |
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=head1 SEE ALSO |
=head1 SEE ALSO |
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C<FUSE (Filesystem in USErspace)> website |
C<FUSE (Filesystem in USErspace)> website |
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L<http://sourceforge.net/projects/avf> |
L<http://fuse.sourceforge.net/> |
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Example for WebGUI which comes with this distribution in |
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directory C<examples/webgui.pl>. It also contains a lot of documentation |
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about design of this module, usage and limitations. |
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=head1 AUTHOR |
=head1 AUTHOR |
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