/[fuse_dbi]/fuse-couchdb/DBI.pm
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revision 18 by dpavlin, Sun Sep 5 16:59:41 2004 UTC revision 23 by dpavlin, Sat Oct 2 16:54:42 2004 UTC
# Line 10  use POSIX qw(ENOENT EISDIR EINVAL ENOSYS Line 10  use POSIX qw(ENOENT EISDIR EINVAL ENOSYS
10  use Fuse;  use Fuse;
11  use DBI;  use DBI;
12  use Carp;  use Carp;
 use Proc::Simple;  
13  use Data::Dumper;  use Data::Dumper;
14    
15    
16  our $VERSION = '0.02';  our $VERSION = '0.03';
17    
18  =head1 NAME  =head1 NAME
19    
# Line 25  Fuse::DBI - mount your database as files Line 24  Fuse::DBI - mount your database as files
24    use Fuse::DBI;    use Fuse::DBI;
25    Fuse::DBI->mount( ... );    Fuse::DBI->mount( ... );
26    
27  See L<run> below for examples how to set parametars.  See C<run> below for examples how to set parametars.
28    
29  =head1 DESCRIPTION  =head1 DESCRIPTION
30    
31  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
33  your database as file system.  your database as file system.
34    
# Line 48  It's actually opposite of Oracle's inten Line 47  It's actually opposite of Oracle's inten
47  Mount your database as filesystem.  Mount your database as filesystem.
48    
49    my $mnt = Fuse::DBI->mount({    my $mnt = Fuse::DBI->mount({
50          filenames => 'select name from filenamefilenames,          filenames => 'select name from files_table as filenames',
51          read => 'sql read',          read => 'sql read',
52          update => 'sql update',          update => 'sql update',
53          dsn => 'DBI:Pg:dbname=webgui',          dsn => 'DBI:Pg:dbname=webgui',
# Line 63  my $sth; Line 62  my $sth;
62  my $ctime_start;  my $ctime_start;
63    
64  sub read_filenames;  sub read_filenames;
65    sub fuse_module_loaded;
66    
67  sub mount {  sub mount {
68          my $class = shift;          my $class = shift;
# Line 83  sub mount { Line 83  sub mount {
83                  carp "mount needs '$_' SQL" unless ($arg->{$_});                  carp "mount needs '$_' SQL" unless ($arg->{$_});
84          }          }
85    
86          $dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, { AutoCommit => 0 }) || die $DBI::errstr;          $ctime_start = time();
87    
88          print "start transaction\n";          my $pid;
89          $dbh->begin_work || die $dbh->errstr;          if ($arg->{'fork'}) {
90                    $pid = fork();
91                    die "fork() failed: $!" unless defined $pid;
92                    # child will return to caller
93                    if ($pid) {
94                            return $self;
95                    }
96            }
97    
98            $dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr;
99    
100          $sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();          $sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();
101    
102          $sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr();          $sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr();
103          $sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr();          $sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr();
104    
105          $ctime_start = time();          $self->read_filenames;
   
         read_filenames;  
106    
107          $self->{'proc'} = Proc::Simple->new();          Fuse::main(
108          $self->{'proc'}->kill_on_destroy(1);                  mountpoint=>$arg->{'mount'},
109                    getattr=>\&e_getattr,
110                    getdir=>\&e_getdir,
111                    open=>\&e_open,
112                    statfs=>\&e_statfs,
113                    read=>\&e_read,
114                    write=>\&e_write,
115                    utime=>\&e_utime,
116                    truncate=>\&e_truncate,
117                    unlink=>\&e_unlink,
118                    debug=>0,
119            );
120    
121          $self->{'proc'}->start( sub {          exit(0) if ($arg->{'fork'});
                 Fuse::main(  
                         mountpoint=>$arg->{'mount'},  
                         getattr=>\&e_getattr,  
                         getdir=>\&e_getdir,  
                         open=>\&e_open,  
                         statfs=>\&e_statfs,  
                         read=>\&e_read,  
                         write=>\&e_write,  
                         utime=>\&e_utime,  
                         truncate=>\&e_truncate,  
                         debug=>0,  
                 );  
         } );  
122    
123          confess "Fuse::main failed" if (! $self->{'proc'}->poll);          return 1;
124    
         $self ? return $self : return undef;  
125  };  };
126    
127  =head2 umount  =head2 umount
# Line 134  database to filesystem. Line 138  database to filesystem.
138  sub umount {  sub umount {
139          my $self = shift;          my $self = shift;
140    
         confess "no process running?" unless ($self->{'proc'});  
   
141          system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";          system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";
142    
143          if ($self->{'proc'}->poll) {          return 1;
144                  $self->{'proc'}->kill;  }
145                  return 1 if (! $self->{'proc'}->poll);  
146          } else {  =head2 fuse_module_loaded
147    
148    Checks if C<fuse> module is loaded in kernel.
149    
150      die "no fuse module loaded in kernel"
151            unless (Fuse::DBI::fuse_module_loaded);
152    
153    This function in called by L<mount>, but might be useful alone also.
154    
155    =cut
156    
157    sub fuse_module_loaded {
158            my $lsmod = `lsmod`;
159            die "can't start lsmod: $!" unless ($lsmod);
160            if ($lsmod =~ m/fuse/s) {
161                  return 1;                  return 1;
162            } else {
163                    return 0;
164          }          }
165  }  }
166    
   
167  my %files;  my %files;
168  my %dirs;  my %dirs;
169    
# Line 252  sub e_getdir { Line 269  sub e_getdir {
269          return (keys %out),0;          return (keys %out),0;
270  }  }
271    
272    sub read_content {
273            my ($file,$id) = @_;
274    
275            die "read_content needs file and id" unless ($file && $id);
276    
277            $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;
278            $files{$file}{cont} = $sth->{'read'}->fetchrow_array;
279            print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n";
280    }
281    
282    
283  sub e_open {  sub e_open {
284          # 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.
285          my $file = filename_fixup(shift);          my $file = filename_fixup(shift);
# Line 260  sub e_open { Line 288  sub e_open {
288          return -ENOENT() unless exists($files{$file});          return -ENOENT() unless exists($files{$file});
289          return -EISDIR() unless exists($files{$file}{id});          return -EISDIR() unless exists($files{$file}{id});
290    
291          if (!exists($files{$file}{cont})) {          read_content($file,$files{$file}{id}) unless exists($files{$file}{cont});
292                  $sth->{'read'}->execute($files{$file}{id}) || die $sth->{'read'}->errstr;  
                 $files{$file}{cont} = $sth->{'read'}->fetchrow_array;  
                 print "file '$file' content read in cache\n";  
         }  
293          print "open '$file' ",length($files{$file}{cont})," bytes\n";          print "open '$file' ",length($files{$file}{cont})," bytes\n";
294          return 0;          return 0;
295  }  }
# Line 285  sub e_read { Line 310  sub e_read {
310          return -EINVAL() if ($off > $len);          return -EINVAL() if ($off > $len);
311          return 0 if ($off == $len);          return 0 if ($off == $len);
312    
313          $buf_len = $buf_len-$off if ($off+$buf_len > $len);          $buf_len = $len-$off if ($len - $off < $buf_len);
314    
315          return substr($files{$file}{cont},$off,$buf_len);          return substr($files{$file}{cont},$off,$buf_len);
316  }  }
# Line 298  sub clear_cont { Line 323  sub clear_cont {
323                  delete $files{$f}{cont};                  delete $files{$f}{cont};
324          }          }
325          print "begin new transaction\n";          print "begin new transaction\n";
326          $dbh->begin_work || die $dbh->errstr;          #$dbh->begin_work || die $dbh->errstr;
327  }  }
328    
329    
# Line 307  sub update_db { Line 332  sub update_db {
332    
333          $files{$file}{ctime} = time();          $files{$file}{ctime} = time();
334    
335          if (!$sth->{'update'}->execute($files{$file}{cont},$files{$file}{id})) {          my ($cont,$id) = (
336                    $files{$file}{cont},
337                    $files{$file}{id}
338            );
339    
340            if (!$sth->{'update'}->execute($cont,$id)) {
341                  print "update problem: ",$sth->{'update'}->errstr;                  print "update problem: ",$sth->{'update'}->errstr;
342                  clear_cont;                  clear_cont;
343                  return 0;                  return 0;
# Line 337  sub e_write { Line 367  sub e_write {
367    
368          $files{$file}{cont} .= substr($cont,0,$off) if ($off > 0);          $files{$file}{cont} .= substr($cont,0,$off) if ($off > 0);
369          $files{$file}{cont} .= $buffer;          $files{$file}{cont} .= $buffer;
370          $files{$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);
371    
372          $files{$file}{size} = length($files{$file}{cont});          $files{$file}{size} = length($files{$file}{cont});
373    
# Line 374  sub e_utime { Line 404  sub e_utime {
404    
405  sub e_statfs { return 255, 1, 1, 1, 1, 2 }  sub e_statfs { return 255, 1, 1, 1, 1, 2 }
406    
407    sub e_unlink {
408            my $file = filename_fixup(shift);
409    
410            return -ENOENT() unless exists($files{$file});
411    
412            print "unlink '$file' will invalidate cache\n";
413    
414            read_content($file,$files{$file}{id});
415    
416            return 0;
417    }
418  1;  1;
419  __END__  __END__
420    
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