From: rkinyon <rkinyon@50811bd7-b8ce-0310-adc1-d9db26280581>
Date: Mon, 18 Dec 2006 06:17:30 +0000 (+0000)
Subject: Added more tests and rollback/commit are kinda working
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=6f999f6ec7671d2cc4315851fbfd8cf68bb44995;p=dbsrgits%2FDBM-Deep.git

Added more tests and rollback/commit are kinda working
---

diff --git a/lib/DBM/Deep/Engine3.pm b/lib/DBM/Deep/Engine3.pm
index fb97a56..b1a5f33 100644
--- a/lib/DBM/Deep/Engine3.pm
+++ b/lib/DBM/Deep/Engine3.pm
@@ -42,6 +42,7 @@ sub new {
     my $class = shift;
     my ($args) = @_;
 
+    print "\n********* NEW ********\n\n";
     my $self = bless {
         byte_size   => 4,
 
@@ -51,6 +52,7 @@ sub new {
         num_txns    => 16, # HEAD plus 15 running txns
         trans_id    => 0,  # Default to the HEAD
 
+        entries => {}, # This is the list of entries for transactions
         storage => undef,
     }, $class;
 
@@ -168,15 +170,6 @@ sub delete_key {
         key_md5    => $self->_apply_digest( $key ),
         allow_head => 0,
     });
-
-    my $key_md5 = $self->_apply_digest( $key );
-
-    # XXX What should happen if this fails?
-    my $blist = $sector->get_bucket_list({
-        key_md5 => $key_md5,
-    }) or die "How did delete_key fail (no blist)?!\n";
-
-    return $blist->delete_md5( $key_md5 );
 }
 
 sub write_value {
@@ -323,7 +316,7 @@ sub begin_work {
     my ($obj) = @_;
 
     if ( $self->trans_id ) {
-        DBM::Deep->throw_error( "Cannot begin_work within a transaction" );
+        DBM::Deep->_throw_error( "Cannot begin_work within a transaction" );
     }
 
     my @slots = $self->read_transaction_slots;
@@ -336,7 +329,7 @@ sub begin_work {
     $self->write_transaction_slots( @slots );
 
     if ( !$self->trans_id ) {
-        DBM::Deep->throw_error( "Cannot begin_work - no available transactions" );
+        DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
     }
 
     return;
@@ -347,8 +340,35 @@ sub rollback {
     my ($obj) = @_;
 
     if ( !$self->trans_id ) {
-        DBM::Deep->throw_error( "Cannot rollback without a transaction" );
+        DBM::Deep->_throw_error( "Cannot rollback without a transaction" );
+    }
+
+    # Each entry is the file location for a bucket that has a modification for
+    # this transaction. The entries need to be expunged.
+    foreach my $entry (@{ $self->get_entries } ) {
+        # Remove the entry here
+        my $read_loc = $entry
+          + $self->hash_size
+          + $self->byte_size
+          + $self->trans_id * $self->byte_size;
+
+        my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
+        $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
+        $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
+
+        if ( $data_loc > 1 ) {
+            $self->_load_sector( $data_loc )->free;
+        }
     }
+
+    $self->clear_entries;
+
+    my @slots = $self->read_transaction_slots;
+    $slots[$self->trans_id] = 0;
+    $self->write_transaction_slots( @slots );
+    $self->set_trans_id( 0 );
+
+    return 1;
 }
 
 sub commit {
@@ -356,8 +376,42 @@ sub commit {
     my ($obj) = @_;
 
     if ( !$self->trans_id ) {
-        DBM::Deep->throw_error( "Cannot commit without a transaction" );
+        DBM::Deep->_throw_error( "Cannot commit without a transaction" );
+    }
+
+    print "TID: " . $self->trans_id, $/;
+    foreach my $entry (@{ $self->get_entries } ) {
+        print "$entry\n";
+        # Overwrite the entry in head with the entry in trans_id
+        my $base = $entry
+          + $self->hash_size
+          + $self->byte_size;
+
+        my $head_loc = $self->storage->read_at( $base, $self->byte_size );
+        $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
+        my $trans_loc = $self->storage->read_at(
+            $base + $self->trans_id * $self->byte_size, $self->byte_size,
+        );
+
+        $self->storage->print_at( $base, $trans_loc );
+        $self->storage->print_at(
+            $base + $self->trans_id * $self->byte_size,
+            pack( $StP{$self->byte_size}, 0 ),
+        );
+
+        if ( $head_loc > 1 ) {
+            $self->_load_sector( $head_loc )->free;
+        }
     }
+
+    $self->clear_entries;
+
+    my @slots = $self->read_transaction_slots;
+    $slots[$self->trans_id] = 0;
+    $self->write_transaction_slots( @slots );
+    $self->set_trans_id( 0 );
+
+    return 1;
 }
 
 sub read_transaction_slots {
@@ -372,6 +426,27 @@ sub write_transaction_slots {
     );
 }
 
+sub get_entries {
+    my $self = shift;
+    return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
+}
+
+sub add_entry {
+    my $self = shift;
+    my ($trans_id, $loc) = @_;
+
+    print "$trans_id => $loc\n";
+    $self->{entries}{$trans_id} ||= {};
+    $self->{entries}{$trans_id}{$loc} = undef;
+    use Data::Dumper;print "$self: " . Dumper $self->{entries};
+}
+
+sub clear_entries {
+    my $self = shift;
+    print "Clearing\n";
+    delete $self->{entries}{$self->trans_id};
+}
+
 ################################################################################
 
 {
@@ -898,7 +973,7 @@ sub write_data {
     my $blist = $self->get_bucket_list({
         key_md5 => $args->{key_md5},
         create  => 1,
-    }) or die "How did write_value fail (no blist)?!\n";
+    }) or die "How did write_data fail (no blist)?!\n";
 
     # Handle any transactional bookkeeping.
     if ( $self->engine->trans_id ) {
@@ -916,6 +991,7 @@ sub write_data {
                 my $old_value = $blist->get_data_for;
                 foreach my $other_trans_id ( @trans_ids ) {
                     next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
+                    print "write_md5 to save a value\n";
                     $blist->write_md5({
                         trans_id => $other_trans_id,
                         key      => $args->{key},
@@ -937,6 +1013,7 @@ sub write_data {
         }
     }
 
+    #XXX Is this safe to do transactionally?
     # Free the place we're about to write to.
     if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
         $blist->get_data_for({ allow_head => 0 })->free;
@@ -958,7 +1035,34 @@ sub delete_key {
         key_md5 => $args->{key_md5},
     }) or die "How did delete_key fail (no blist)?!\n";
 
-    return $blist->delete_md5( $args );
+    # Save the location so that we can free the data
+    my $location = $blist->get_data_location_for({
+        allow_head => 0,
+    });
+    my $old_value = $self->engine->_load_sector( $location );
+
+    if ( $self->engine->trans_id == 0 ) {
+        my @transactions = $self->engine->read_transaction_slots;
+        my @trans_ids = grep { $transactions[$_] } 0 .. $#transactions;
+        if ( @trans_ids ) {
+            foreach my $other_trans_id ( @trans_ids ) {
+                next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
+                $blist->write_md5({
+                    trans_id => $other_trans_id,
+                    key      => $args->{key},
+                    key_md5  => $args->{key_md5},
+                    value    => $old_value->clone,
+                });
+            }
+        }
+    }
+
+    $blist->mark_deleted( $args );
+
+    my $data = $old_value->data;
+    $old_value->free;
+
+    return $data;
 }
 
 sub get_blist_loc {
@@ -1103,7 +1207,7 @@ sub find_md5 {
 
     # If we don't have an MD5, then what are we supposed to do?
     unless ( exists $self->{key_md5} ) {
-        DBM::Deep->throw( "Cannot find_md5 without a key_md5 set" );
+        DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
     }
 
     my $e = $self->engine;
@@ -1130,30 +1234,37 @@ sub find_md5 {
 sub write_md5 {
     my $self = shift;
     my ($args) = @_;
-    $args ||= {};
 
-    $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
+    DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
+    DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
+    DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
 
     my $engine = $self->engine;
+
+    $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
+
     my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
+    print "Adding $args->{trans_id} -> $spot\n";
+    $engine->add_entry( $args->{trans_id}, $spot );
 
     unless ($self->{found}) {
         my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
-            engine => $self->engine,
+            engine => $engine,
             data   => $args->{key},
         });
 
         $engine->storage->print_at( $spot,
             $args->{key_md5},
-            pack( $StP{$self->engine->byte_size}, $key_sector->offset ),
+            pack( $StP{$engine->byte_size}, $key_sector->offset ),
         );
     }
 
-    $engine->storage->print_at(
-        $spot
+    my $loc = $spot
       + $engine->hash_size
       + $engine->byte_size
-      + $args->{trans_id} * $engine->byte_size,
+      + $args->{trans_id} * $engine->byte_size;
+
+    $engine->storage->print_at( $loc,
         pack( $StP{$engine->byte_size}, $args->{value}->offset ),
     );
 }
@@ -1161,14 +1272,22 @@ sub write_md5 {
 sub mark_deleted {
     my $self = shift;
     my ($args) = @_;
+    $args ||= {};
+
+    my $engine = $self->engine;
+
+    $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
 
     my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
-    $self->engine->storage->print_at(
-        $spot
-      + $self->engine->hash_size
-      + $self->engine->byte_size
-      + $args->{trans_id} * $self->engine->byte_size,
-        pack( $StP{$self->engine->byte_size}, 1 ), # 1 is the marker for deleted
+    $engine->add_entry( $args->{trans_id}, $spot );
+
+    my $loc = $spot
+      + $engine->hash_size
+      + $engine->byte_size
+      + $args->{trans_id} * $engine->byte_size;
+
+    $engine->storage->print_at( $loc,
+        pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
     );
 }
 
@@ -1185,6 +1304,8 @@ sub delete_md5 {
     });
     my $key_sector = $self->get_key_for;
 
+    #XXX This isn't going to work right and you know it! This eradicates data
+    # that we're not ready to eradicate just yet.
     my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
     $engine->storage->print_at( $spot,
         $engine->storage->read_at(
diff --git a/t/33_transactions.t b/t/33_transactions.t
index 77c2fef..dbed193 100644
--- a/t/33_transactions.t
+++ b/t/33_transactions.t
@@ -59,8 +59,6 @@ ok( $@, "Attempting to begin_work within a transaction throws an error" );
 
     cmp_bag( [ keys %$db1 ], [qw( x z )], "DB1 keys correct" );
     cmp_bag( [ keys %$db2 ], [qw( x other_x )], "DB2 keys correct" );
-SKIP:{ skip "unfinished yet", 51 }
-__END__
 
 $db1->rollback;
 
@@ -83,7 +81,11 @@ $db1->begin_work;
     is( $db2->{other_x}, 'bar', "DB2 set other_x within DB1's transaction, so DB2 can see it" );
     is( $db1->{other_x}, 'foo', "Since other_x was modified after the transaction began, DB1 doesn't see the change." );
 
-    cmp_bag( [ keys %$db1 ], [qw( x other_x )], "DB1 keys correct" );
+    $db1->{z} = 'a';
+    is( $db1->{z}, 'a', "Within DB1 transaction, DB1's Z is A" );
+    ok( !exists $db2->{z}, "Since z was added after the transaction began, DB2 doesn't see it." );
+
+    cmp_bag( [ keys %$db1 ], [qw( x other_x z )], "DB1 keys correct" );
     cmp_bag( [ keys %$db2 ], [qw( x other_x )], "DB2 keys correct" );
 
 $db1->commit;
@@ -91,12 +93,27 @@ $db1->commit;
 is( $db1->{x}, 'z', "After commit, DB1's X is Z" );
 is( $db2->{x}, 'z', "After commit, DB2's X is Z" );
 
+is( $db1->{z}, 'a', "After commit, DB1's Z is A" );
+is( $db2->{z}, 'a', "After commit, DB2's Z is A" );
+
+is( $db1->{other_x}, 'bar', "After commit, DB1's other_x is bar" );
+is( $db2->{other_x}, 'bar', "After commit, DB2's other_x is bar" );
+
 $db1->begin_work;
 
+    is( $db1->{x}, 'z', "After commit, DB1's X is Z" );
+    is( $db2->{x}, 'z', "After commit, DB2's X is Z" );
+
+    is( $db1->{z}, 'a', "After commit, DB1's Z is A" );
+    is( $db2->{z}, 'a', "After commit, DB2's Z is A" );
+
+    is( $db1->{other_x}, 'bar', "After begin_work, DB1's other_x is still bar" );
+    is( $db2->{other_x}, 'bar', "After begin_work, DB2's other_x is still bar" );
+__END__
     delete $db2->{other_x};
     ok( !exists $db2->{other_x}, "DB2 deleted other_x in DB1's transaction, so it can't see it anymore" );
     is( $db1->{other_x}, 'bar', "Since other_x was deleted after the transaction began, DB1 still sees it." );
-
+__END__
     cmp_bag( [ keys %$db1 ], [qw( x other_x )], "DB1 keys correct" );
     cmp_bag( [ keys %$db2 ], [qw( x )], "DB2 keys correct" );