Converted to using only 2 transactions by default and added the num_txns to the header

[dbsrgits/DBM-Deep.git] / lib / DBM / Deep / Engine.pm

diff --git a/lib/DBM/Deep/Engine.pm b/lib/DBM/Deep/Engine.pm
index 26c3000..0381bf1 100644 (file)
--- a/lib/DBM/Deep/Engine.pm
+++ b/lib/DBM/Deep/Engine.pm
@@ -50,8 +50,8 @@ sub new {
         hash_size   => 16,  # In bytes
         hash_chars  => 256, # Number of chars the algorithm uses per byte
         max_buckets => 16,
-        num_txns    => 16, # HEAD plus 15 running txns
-        trans_id    => 0,  # Default to the HEAD
+        num_txns    => 2,   # HEAD plus 1 additional transaction for importing
+        trans_id    => 0,   # Default to the HEAD
 
         entries => {}, # This is the list of entries for transactions
         storage => undef,
@@ -534,7 +534,7 @@ sub clear_entries {
     sub _write_file_header {
         my $self = shift;
 
-        my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
+        my $header_var = 1 + 1 + 1 + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
 
         my $loc = $self->storage->request_space( $header_fixed + $header_var );
 
@@ -546,6 +546,7 @@ sub clear_entries {
             # --- Above is $header_fixed. Below is $header_var
             pack('C', $self->byte_size),
             pack('C', $self->max_buckets),
+            pack('C', $self->num_txns),
             pack('N', 0 ),                   # Transaction activeness bitfield
             pack('N' . $self->num_txns, 0 x $self->num_txns ), # Transaction staleness counters
             pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
@@ -553,8 +554,8 @@ sub clear_entries {
             pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
         );
 
-        $self->set_trans_loc( $header_fixed + 2 );
-        $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
+        $self->set_trans_loc( $header_fixed + 3 );
+        $self->set_chains_loc( $header_fixed + 3 + 4 + 4 * $self->num_txns );
 
         return;
     }
@@ -580,20 +581,20 @@ sub clear_entries {
         }
 
         my $buffer2 = $self->storage->read_at( undef, $size );
-        my @values = unpack( 'C C', $buffer2 );
+        my @values = unpack( 'C C C', $buffer2 );
 
-        $self->set_trans_loc( $header_fixed + 2 );
-        $self->set_chains_loc( $header_fixed + 2 + 4 + 4 * $self->num_txns );
-
-        if ( @values < 2 || grep { !defined } @values ) {
+        if ( @values != 3 || grep { !defined } @values ) {
             $self->storage->close;
             DBM::Deep->_throw_error("Corrupted file - bad header");
         }
 
+        $self->set_trans_loc( $header_fixed + scalar(@values) );
+        $self->set_chains_loc( $header_fixed + scalar(@values) + 4 + 4 * $self->num_txns );
+
         #XXX Add warnings if values weren't set right
-        @{$self}{qw(byte_size max_buckets)} = @values;
+        @{$self}{qw(byte_size max_buckets num_txns)} = @values;
 
-        my $header_var = 1 + 1 + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
+        my $header_var = scalar(@values) + 4 + 4 * $self->num_txns + 3 * $self->byte_size;
         unless ( $size == $header_var ) {
             $self->storage->close;
             DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );