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use Fuse; |
use Fuse; |
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use DBI; |
use DBI; |
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use Carp; |
use Carp; |
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use Proc::Simple; |
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use Data::Dumper; |
use Data::Dumper; |
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our $VERSION = '0.02'; |
our $VERSION = '0.04'; |
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=head1 NAME |
=head1 NAME |
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|
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use Fuse::DBI; |
use Fuse::DBI; |
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Fuse::DBI->mount( ... ); |
Fuse::DBI->mount( ... ); |
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|
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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)> |
32 |
available at L<http://sourceforge.net/projects/avf> to mount |
available at L<http://sourceforge.net/projects/avf> to mount |
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your database as file system. |
your database as file system. |
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|
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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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|
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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 filenamefilenames, |
'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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my $ctime_start; |
my $ctime_start; |
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sub read_filenames; |
sub read_filenames; |
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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 $class = shift; |
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carp "mount needs 'mount' as mountpoint" unless ($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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} |
} |
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$dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, { AutoCommit => 0 }) || die $DBI::errstr; |
$ctime_start = time(); |
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my $pid; |
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if ($arg->{'fork'}) { |
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$pid = fork(); |
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die "fork() failed: $!" unless defined $pid; |
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# child will return to caller |
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if ($pid) { |
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return $self; |
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} |
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} |
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print "start transaction\n"; |
$dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr; |
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$dbh->begin_work || die $dbh->errstr; |
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$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 $dbh->errstr(); |
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$ctime_start = time(); |
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read_filenames; |
$self->{'sth'} = $sth; |
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$self->{'read_filenames'} = sub { $self->read_filenames }; |
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$self->read_filenames; |
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$self->{'proc'} = Proc::Simple->new(); |
$self->{'mounted'} = 1; |
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$self->{'proc'}->kill_on_destroy(1); |
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$self->{'proc'}->start( sub { |
$fuse_self = \$self; |
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Fuse::main( |
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mountpoint=>$arg->{'mount'}, |
Fuse::main( |
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getattr=>\&e_getattr, |
mountpoint=>$arg->{'mount'}, |
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getdir=>\&e_getdir, |
getattr=>\&e_getattr, |
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open=>\&e_open, |
getdir=>\&e_getdir, |
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statfs=>\&e_statfs, |
open=>\&e_open, |
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read=>\&e_read, |
statfs=>\&e_statfs, |
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write=>\&e_write, |
read=>\&e_read, |
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utime=>\&e_utime, |
write=>\&e_write, |
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truncate=>\&e_truncate, |
utime=>\&e_utime, |
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debug=>0, |
truncate=>\&e_truncate, |
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); |
unlink=>\&e_unlink, |
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} ); |
rmdir=>\&e_unlink, |
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debug=>0, |
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); |
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$self->{'mounted'} = 0; |
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confess "Fuse::main failed" if (! $self->{'proc'}->poll); |
exit(0) if ($arg->{'fork'}); |
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return 1; |
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$self ? return $self : return undef; |
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}; |
}; |
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=head2 umount |
=head2 umount |
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sub umount { |
sub umount { |
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my $self = shift; |
my $self = shift; |
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confess "no process running?" unless ($self->{'proc'}); |
if ($self->{'mounted'}) { |
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system "fusermount -u ".$self->{'mount'} || croak "umount error: $!"; |
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} |
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return 1; |
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} |
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$SIG{'INT'} = sub { |
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print STDERR "umount called by SIG INT\n"; |
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umount; |
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}; |
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sub DESTROY { |
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my $self = shift; |
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return if (! $self->{'mounted'}); |
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print STDERR "umount called by DESTROY\n"; |
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$self->umount; |
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} |
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=head2 fuse_module_loaded |
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system "fusermount -u ".$self->{'mount'} || croak "umount error: $!"; |
Checks if C<fuse> module is loaded in kernel. |
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if ($self->{'proc'}->poll) { |
die "no fuse module loaded in kernel" |
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$self->{'proc'}->kill; |
unless (Fuse::DBI::fuse_module_loaded); |
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return 1 if (! $self->{'proc'}->poll); |
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} else { |
This function in called by C<mount>, but might be useful alone also. |
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=cut |
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sub fuse_module_loaded { |
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my $lsmod = `lsmod`; |
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die "can't start lsmod: $!" unless ($lsmod); |
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if ($lsmod =~ m/fuse/s) { |
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return 1; |
return 1; |
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} else { |
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return 0; |
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} |
} |
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} |
} |
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my %files; |
my %files; |
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my %dirs; |
my %dirs; |
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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 = $self->{'sth'} || die "no sth argument"; |
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# create empty filesystem |
# create empty filesystem |
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(%files) = ( |
(%files) = ( |
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'.' => { |
'.' => { |
357 |
return (keys %out),0; |
return (keys %out),0; |
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} |
} |
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sub read_content { |
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my ($file,$id) = @_; |
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die "read_content needs file and id" unless ($file && $id); |
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$sth->{'read'}->execute($id) || die $sth->{'read'}->errstr; |
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$files{$file}{cont} = $sth->{'read'}->fetchrow_array; |
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$files{$file}{ctime} = time(); |
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print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n"; |
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} |
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sub e_open { |
sub e_open { |
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# VFS sanity check; it keeps all the necessary state, not much to do here. |
# VFS sanity check; it keeps all the necessary state, not much to do here. |
374 |
my $file = filename_fixup(shift); |
my $file = filename_fixup(shift); |
377 |
return -ENOENT() unless exists($files{$file}); |
return -ENOENT() unless exists($files{$file}); |
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return -EISDIR() unless exists($files{$file}{id}); |
return -EISDIR() unless exists($files{$file}{id}); |
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|
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if (!exists($files{$file}{cont})) { |
read_content($file,$files{$file}{id}) unless exists($files{$file}{cont}); |
381 |
$sth->{'read'}->execute($files{$file}{id}) || die $sth->{'read'}->errstr; |
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$files{$file}{cont} = $sth->{'read'}->fetchrow_array; |
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print "file '$file' content read in cache\n"; |
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} |
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print "open '$file' ",length($files{$file}{cont})," bytes\n"; |
print "open '$file' ",length($files{$file}{cont})," bytes\n"; |
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return 0; |
return 0; |
384 |
} |
} |
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return -EINVAL() if ($off > $len); |
return -EINVAL() if ($off > $len); |
400 |
return 0 if ($off == $len); |
return 0 if ($off == $len); |
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$buf_len = $buf_len-$off if ($off+$buf_len > $len); |
$buf_len = $len-$off if ($len - $off < $buf_len); |
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|
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return substr($files{$file}{cont},$off,$buf_len); |
return substr($files{$file}{cont},$off,$buf_len); |
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} |
} |
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delete $files{$f}{cont}; |
delete $files{$f}{cont}; |
413 |
} |
} |
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print "begin new transaction\n"; |
print "begin new transaction\n"; |
415 |
$dbh->begin_work || die $dbh->errstr; |
#$dbh->begin_work || die $dbh->errstr; |
416 |
} |
} |
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$files{$file}{ctime} = time(); |
$files{$file}{ctime} = time(); |
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if (!$sth->{'update'}->execute($files{$file}{cont},$files{$file}{id})) { |
my ($cont,$id) = ( |
425 |
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$files{$file}{cont}, |
426 |
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$files{$file}{id} |
427 |
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); |
428 |
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if (!$sth->{'update'}->execute($cont,$id)) { |
430 |
print "update problem: ",$sth->{'update'}->errstr; |
print "update problem: ",$sth->{'update'}->errstr; |
431 |
clear_cont; |
clear_cont; |
432 |
return 0; |
return 0; |
437 |
return 0; |
return 0; |
438 |
} |
} |
439 |
print "updated '$file' [",$files{$file}{id},"]\n"; |
print "updated '$file' [",$files{$file}{id},"]\n"; |
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|
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$$fuse_self->{'invalidate'}->() if (ref $$fuse_self->{'invalidate'}); |
442 |
} |
} |
443 |
return 1; |
return 1; |
444 |
} |
} |
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459 |
$files{$file}{cont} .= substr($cont,0,$off) if ($off > 0); |
$files{$file}{cont} .= substr($cont,0,$off) if ($off > 0); |
460 |
$files{$file}{cont} .= $buffer; |
$files{$file}{cont} .= $buffer; |
461 |
$files{$file}{cont} .= substr($cont,-($off+length($buffer))) if ($off+length($buffer) > $len); |
$files{$file}{cont} .= substr($cont,$off+length($buffer),$len-$off-length($buffer)) if ($off+length($buffer) < $len); |
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$files{$file}{size} = length($files{$file}{cont}); |
$files{$file}{size} = length($files{$file}{cont}); |
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sub e_statfs { return 255, 1, 1, 1, 1, 2 } |
sub e_statfs { return 255, 1, 1, 1, 1, 2 } |
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sub e_unlink { |
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my $file = filename_fixup(shift); |
500 |
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if (exists( $dirs{$file} )) { |
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print "unlink '$file' will re-read template names\n"; |
503 |
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print Dumper($fuse_self); |
504 |
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$$fuse_self->{'read_filenames'}->(); |
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return 0; |
506 |
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} elsif (exists( $files{$file} )) { |
507 |
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print "unlink '$file' will invalidate cache\n"; |
508 |
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read_content($file,$files{$file}{id}); |
509 |
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return 0; |
510 |
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} |
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return -ENOENT(); |
513 |
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} |
514 |
1; |
1; |
515 |
__END__ |
__END__ |
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|
523 |
C<FUSE (Filesystem in USErspace)> website |
C<FUSE (Filesystem in USErspace)> website |
524 |
L<http://sourceforge.net/projects/avf> |
L<http://sourceforge.net/projects/avf> |
525 |
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|
526 |
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Example for WebGUI which comes with this distribution in |
527 |
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directory L<examples/webgui.pl>. It also contains a lot of documentation |
528 |
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about design of this module, usage and limitations. |
529 |
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530 |
=head1 AUTHOR |
=head1 AUTHOR |
531 |
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|
532 |
Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt> |
Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt> |