/[fuse_dbi]/fuse-couchdb/DBI.pm
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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revision 9 by dpavlin, Sat Aug 7 19:06:03 2004 UTC revision 24 by dpavlin, Fri Oct 8 20:07:12 2004 UTC
# Line 9  use warnings; Line 9  use warnings;
9  use POSIX qw(ENOENT EISDIR EINVAL ENOSYS O_RDWR);  use POSIX qw(ENOENT EISDIR EINVAL ENOSYS O_RDWR);
10  use Fuse;  use Fuse;
11  use DBI;  use DBI;
12    use Carp;
13    use Data::Dumper;
14    
15  our $VERSION = '0.01';  
16    our $VERSION = '0.03';
17    
18  =head1 NAME  =head1 NAME
19    
# Line 19  Fuse::DBI - mount your database as files Line 22  Fuse::DBI - mount your database as files
22  =head1 SYNOPSIS  =head1 SYNOPSIS
23    
24    use Fuse::DBI;    use Fuse::DBI;
25    Fuse::DBI->run( ... );    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 39  It's actually opposite of Oracle's inten Line 42  It's actually opposite of Oracle's inten
42    
43  =cut  =cut
44    
45  =head2 run  =head2 mount
46    
47  Mount your database as filesystem.  Mount your database as filesystem.
48    
49    Fuse::DBI->run({    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 58  my $dbh; Line 61  my $dbh;
61  my $sth;  my $sth;
62  my $ctime_start;  my $ctime_start;
63    
64  sub run {  sub read_filenames;
65          my $self = shift  sub fuse_module_loaded;
   
         my $arg = {@_};  
66    
67          carp "run needs 'dsn' to connect to (e.g. dsn => 'DBI:Pg:dbname=test')" unless ($arg->{'dsn'});  # evil, evil way to solve this. It makes this module non-reentrant. But, since
68          carp "run needs 'mount' as mountpoint" unless ($arg->{'mount'});  # fuse calls another copy of this script for each mount anyway, this shouldn't
69    # be a problem.
70    my $fuse_self;
71    
72    sub mount {
73            my $class = shift;
74            my $self = {};
75            bless($self, $class);
76    
77            my $arg = shift;
78    
79            print Dumper($arg);
80    
81            carp "mount needs 'dsn' to connect to (e.g. dsn => 'DBI:Pg:dbname=test')" unless ($arg->{'dsn'});
82            carp "mount needs 'mount' as mountpoint" unless ($arg->{'mount'});
83    
84            # save (some) arguments in self
85            foreach (qw(mount invalidate)) {
86                    $self->{$_} = $arg->{$_};
87                    $fuse_self->{$_} = $arg->{$_};
88            }
89    
90          foreach (qw(filenames read update)) {          foreach (qw(filenames read update)) {
91                  carp "run needs '$_' SQL" unless ($arg->{$_});                  carp "mount needs '$_' SQL" unless ($arg->{$_});
92          }          }
93    
94          $dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, { AutoCommit => 0 }) || die $DBI::errstr;          $ctime_start = time();
95    
96            my $pid;
97            if ($arg->{'fork'}) {
98                    $pid = fork();
99                    die "fork() failed: $!" unless defined $pid;
100                    # child will return to caller
101                    if ($pid) {
102                            return $self;
103                    }
104            }
105    
106          print "start transaction\n";          $dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr;
         #$dbh->begin_work || die $dbh->errstr;  
107    
108          $sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();          $sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();
109    
110          $sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr();          $sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr();
111          $sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr();          $sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr();
112    
113          $ctime_start = time();          $self->read_filenames;
   
         read_filenames;  
114    
115          Fuse::main(          Fuse::main(
116                  mountpoint=>$arg->{'mount'},                  mountpoint=>$arg->{'mount'},
# Line 94  sub run { Line 122  sub run {
122                  write=>\&e_write,                  write=>\&e_write,
123                  utime=>\&e_utime,                  utime=>\&e_utime,
124                  truncate=>\&e_truncate,                  truncate=>\&e_truncate,
125                    unlink=>\&e_unlink,
126                  debug=>0,                  debug=>0,
127          );          );
128    
129            exit(0) if ($arg->{'fork'});
130    
131            return 1;
132    
133  };  };
134    
135    =head2 umount
136    
137    Unmount your database as filesystem.
138    
139      $mnt->umount;
140    
141    This will also kill background process which is translating
142    database to filesystem.
143    
144    =cut
145    
146    sub umount {
147            my $self = shift;
148    
149            system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";
150    
151            return 1;
152    }
153    
154    #$SIG{'INT'} = sub {
155    #       print STDERR "umount called by SIG INT\n";
156    #       umount;
157    #};
158    
159    sub DESTROY {
160            my $self = shift;
161            print STDERR "umount called by DESTROY\n";
162            $self->umount;
163    }
164    
165    =head2 fuse_module_loaded
166    
167    Checks if C<fuse> module is loaded in kernel.
168    
169      die "no fuse module loaded in kernel"
170            unless (Fuse::DBI::fuse_module_loaded);
171    
172    This function in called by L<mount>, but might be useful alone also.
173    
174    =cut
175    
176    sub fuse_module_loaded {
177            my $lsmod = `lsmod`;
178            die "can't start lsmod: $!" unless ($lsmod);
179            if ($lsmod =~ m/fuse/s) {
180                    return 1;
181            } else {
182                    return 0;
183            }
184    }
185    
186  my %files;  my %files;
187  my %dirs;  my %dirs;
188    
189  sub read_filenames {  sub read_filenames {
190            my $self = shift;
191    
192          # create empty filesystem          # create empty filesystem
193          (%files) = (          (%files) = (
194                  '.' => {                  '.' => {
# Line 184  sub e_getdir { Line 271  sub e_getdir {
271          # return as many text filenames as you like, followed by the retval.          # return as many text filenames as you like, followed by the retval.
272          print((scalar keys %files)." files total\n");          print((scalar keys %files)." files total\n");
273          my %out;          my %out;
274          foreach (keys %files) {          foreach my $f (sort keys %files) {
                 my $f = $_;  
                 $f =~ s/^\E$dirname\Q//;  
                 $f =~ s/^\///;  
275                  if ($dirname) {                  if ($dirname) {
276                          $out{$f}++ if (/^\E$dirname\Q/ && $f =~ /^[^\/]+$/);                          if ($f =~ s/^\E$dirname\Q\///) {
277                                    $out{$f}++ if ($f =~ /^[^\/]+$/);
278                            }
279                  } else {                  } else {
280                          $out{$f}++ if ($f =~ /^[^\/]+$/);                          $out{$f}++ if ($f =~ /^[^\/]+$/);
281                  }                  }
# Line 198  sub e_getdir { Line 284  sub e_getdir {
284                  $out{'no files? bug?'}++;                  $out{'no files? bug?'}++;
285          }          }
286          print scalar keys %out," files in dir '$dirname'\n";          print scalar keys %out," files in dir '$dirname'\n";
287            print "## ",join(" ",keys %out),"\n";
288          return (keys %out),0;          return (keys %out),0;
289  }  }
290    
291    sub read_content {
292            my ($file,$id) = @_;
293    
294            die "read_content needs file and id" unless ($file && $id);
295    
296            $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;
297            $files{$file}{cont} = $sth->{'read'}->fetchrow_array;
298            print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n";
299    }
300    
301    
302  sub e_open {  sub e_open {
303          # 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.
304          my $file = filename_fixup(shift);          my $file = filename_fixup(shift);
# Line 209  sub e_open { Line 307  sub e_open {
307          return -ENOENT() unless exists($files{$file});          return -ENOENT() unless exists($files{$file});
308          return -EISDIR() unless exists($files{$file}{id});          return -EISDIR() unless exists($files{$file}{id});
309    
310          if (!exists($files{$file}{cont})) {          read_content($file,$files{$file}{id}) unless exists($files{$file}{cont});
311                  $sth->{'read'}->execute($files{$file}{id}) || die $sth->{'read'}->errstr;  
                 $files{$file}{cont} = $sth->{'read'}->fetchrow_array;  
                 print "file '$file' content read in cache\n";  
         }  
312          print "open '$file' ",length($files{$file}{cont})," bytes\n";          print "open '$file' ",length($files{$file}{cont})," bytes\n";
313          return 0;          return 0;
314  }  }
# Line 234  sub e_read { Line 329  sub e_read {
329          return -EINVAL() if ($off > $len);          return -EINVAL() if ($off > $len);
330          return 0 if ($off == $len);          return 0 if ($off == $len);
331    
332          $buf_len = $buf_len-$off if ($off+$buf_len > $len);          $buf_len = $len-$off if ($len - $off < $buf_len);
333    
334          return substr($files{$file}{cont},$off,$buf_len);          return substr($files{$file}{cont},$off,$buf_len);
335  }  }
# Line 247  sub clear_cont { Line 342  sub clear_cont {
342                  delete $files{$f}{cont};                  delete $files{$f}{cont};
343          }          }
344          print "begin new transaction\n";          print "begin new transaction\n";
345          $dbh->begin_work || die $dbh->errstr;          #$dbh->begin_work || die $dbh->errstr;
346  }  }
347    
348    
# Line 256  sub update_db { Line 351  sub update_db {
351    
352          $files{$file}{ctime} = time();          $files{$file}{ctime} = time();
353    
354          if (!$sth->{'update'}->execute($files{$file}{cont},$files{$file}{id})) {          my ($cont,$id) = (
355                    $files{$file}{cont},
356                    $files{$file}{id}
357            );
358    
359            if (!$sth->{'update'}->execute($cont,$id)) {
360                  print "update problem: ",$sth->{'update'}->errstr;                  print "update problem: ",$sth->{'update'}->errstr;
361                  clear_cont;                  clear_cont;
362                  return 0;                  return 0;
# Line 267  sub update_db { Line 367  sub update_db {
367                          return 0;                          return 0;
368                  }                  }
369                  print "updated '$file' [",$files{$file}{id},"]\n";                  print "updated '$file' [",$files{$file}{id},"]\n";
370    
371                    $fuse_self->{'invalidate'}->() if (ref $fuse_self->{'invalidate'});
372          }          }
373          return 1;          return 1;
374  }  }
375    
376  sub e_write {  sub e_write {
377          my $file = filename_fixup(shift);          my $file = filename_fixup(shift);
378          my ($buf_len,$off) = @_;          my ($buffer,$off) = @_;
379    
380          return -ENOENT() unless exists($files{$file});          return -ENOENT() unless exists($files{$file});
381    
382          my $len = length($files{$file}{cont});          my $cont = $files{$file}{cont};
383            my $len = length($cont);
384    
385            print "write '$file' [$len bytes] offset $off length ",length($buffer),"\n";
386    
387          print "write '$file' [$len bytes] offset $off length\n";          $files{$file}{cont} = "";
388    
389          $files{$file}{cont} =          $files{$file}{cont} .= substr($cont,0,$off) if ($off > 0);
390                  substr($files{$file}{cont},0,$off) .          $files{$file}{cont} .= $buffer;
391                  $buf_len .          $files{$file}{cont} .= substr($cont,$off+length($buffer),$len-$off-length($buffer)) if ($off+length($buffer) < $len);
392                  substr($files{$file}{cont},$off+length($buf_len));  
393            $files{$file}{size} = length($files{$file}{cont});
394    
395          if (! update_db($file)) {          if (! update_db($file)) {
396                  return -ENOSYS();                  return -ENOSYS();
397          } else {          } else {
398                  return length($buf_len);                  return length($buffer);
399          }          }
400  }  }
401    
# Line 297  sub e_truncate { Line 403  sub e_truncate {
403          my $file = filename_fixup(shift);          my $file = filename_fixup(shift);
404          my $size = shift;          my $size = shift;
405    
406            print "truncate to $size\n";
407    
408          $files{$file}{cont} = substr($files{$file}{cont},0,$size);          $files{$file}{cont} = substr($files{$file}{cont},0,$size);
409            $files{$file}{size} = $size;
410          return 0          return 0
411  };  };
412    
# Line 316  sub e_utime { Line 425  sub e_utime {
425    
426  sub e_statfs { return 255, 1, 1, 1, 1, 2 }  sub e_statfs { return 255, 1, 1, 1, 1, 2 }
427    
428    sub e_unlink {
429            my $file = filename_fixup(shift);
430    
431            return -ENOENT() unless exists($files{$file});
432    
433            print "unlink '$file' will invalidate cache\n";
434    
435            read_content($file,$files{$file}{id});
436    
437            return 0;
438    }
439  1;  1;
440  __END__  __END__
441    
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