1 package DBM::Deep::Engine;
5 use Fcntl qw( :DEFAULT :flock :seek );
9 # Open a fh to the database, create if nonexistent.
10 # Make sure file signature matches DBM::Deep spec.
15 if (defined($self->_fh)) { $self->_close(); }
18 local $SIG{'__DIE__'};
19 # Theoretically, adding O_BINARY should remove the need for the binmode
20 # Of course, testing it is going to be ... interesting.
21 my $flags = O_RDWR | O_CREAT | O_BINARY;
24 sysopen( $fh, $self->_root->{file}, $flags )
26 $self->_root->{fh} = $fh;
27 }; if ($@ ) { $self->_throw_error( "Received error: $@\n" ); }
28 if (! defined($self->_fh)) {
29 return $self->_throw_error("Cannot sysopen file: " . $self->_root->{file} . ": $!");
34 #XXX Can we remove this by using the right sysopen() flags?
35 # Maybe ... q.v. above
36 binmode $fh; # for win32
38 if ($self->_root->{autoflush}) {
44 seek($fh, 0 + $self->_root->{file_offset}, SEEK_SET);
47 my $bytes_read = read( $fh, $signature, length(DBM::Deep->SIG_FILE));
50 # File is empty -- write signature and master index
53 seek($fh, 0 + $self->_root->{file_offset}, SEEK_SET);
54 print( $fh DBM::Deep->SIG_FILE);
55 $self->_create_tag($self->_base_offset, $self->_type, chr(0) x $DBM::Deep::INDEX_SIZE);
57 my $plain_key = "[base]";
58 print( $fh pack($DBM::Deep::DATA_LENGTH_PACK, length($plain_key)) . $plain_key );
60 # Flush the filehandle
61 my $old_fh = select $fh;
62 my $old_af = $|; $| = 1; $| = $old_af;
65 my @stats = stat($fh);
66 $self->_root->{inode} = $stats[1];
67 $self->_root->{end} = $stats[7];
73 # Check signature was valid
75 unless ($signature eq DBM::Deep->SIG_FILE) {
77 return $self->_throw_error("Signature not found -- file is not a Deep DB");
80 my @stats = stat($fh);
81 $self->_root->{inode} = $stats[1];
82 $self->_root->{end} = $stats[7];
85 # Get our type from master index signature
87 my $tag = $self->_load_tag($self->_base_offset);
89 #XXX We probably also want to store the hash algorithm name and not assume anything
90 #XXX The cool thing would be to allow a different hashing algorithm at every level
93 return $self->_throw_error("Corrupted file, no master index record");
95 if ($self->{type} ne $tag->{signature}) {
96 return $self->_throw_error("File type mismatch");