X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FTxnScopeGuard.pm;h=f961c4e4446b00796286a577a92e58a592bb908d;hb=12a184d0a0c1868708e43aaabefe08f9e7ac9ec4;hp=574587007a3c3d36a610f62e59064003be658934;hpb=a778f387401f12b9823aeab5afd200b3623d31a8;p=dbsrgits%2FDBIx-Class-Historic.git diff --git a/lib/DBIx/Class/Storage/TxnScopeGuard.pm b/lib/DBIx/Class/Storage/TxnScopeGuard.pm index 5745870..f961c4e 100644 --- a/lib/DBIx/Class/Storage/TxnScopeGuard.pm +++ b/lib/DBIx/Class/Storage/TxnScopeGuard.pm @@ -1,50 +1,113 @@ -package # Hide from pause for now - till we get it working - DBIx::Class::Storage::TxnScopeGuard; +package DBIx::Class::Storage::TxnScopeGuard; use strict; use warnings; +use Scalar::Util qw(weaken blessed refaddr); +use DBIx::Class; +use DBIx::Class::_Util qw(is_exception detected_reinvoked_destructor); +use DBIx::Class::Carp; +use namespace::clean; sub new { my ($class, $storage) = @_; + my $guard = { + inactivated => 0, + storage => $storage, + }; + + # we are starting with an already set $@ - in order for things to work we need to + # be able to recognize it upon destruction - store its weakref + # recording it before doing the txn_begin stuff + # + # FIXME FRAGILE - any eval that fails but *does not* rethrow between here + # and the unwind will trample over $@ and invalidate the entire mechanism + # There got to be a saner way of doing this... + # + # Deliberately *NOT* using is_exception - if someone left a misbehaving + # antipattern value in $@, it's not our business to whine about it + weaken( + $guard->{existing_exception_ref} = (length ref $@) ? $@ : \$@ + ) if( defined $@ and length $@ ); + $storage->txn_begin; - bless [ 0, $storage ], ref $class || $class; + + weaken( $guard->{dbh} = $storage->_dbh ); + + bless $guard, ref $class || $class; + + $guard; } sub commit { my $self = shift; - $self->[1]->txn_commit; - $self->[0] = 1; -} + $self->{storage}->throw_exception("Refusing to execute multiple commits on scope guard $self") + if $self->{inactivated}; -sub dismiss { - my $self = shift; - - $self->[0] = 1; + # FIXME - this assumption may be premature: a commit may fail and a rollback + # *still* be necessary. Currently I am not aware of such scenarious, but I + # also know the deferred constraint handling is *severely* undertested. + # Making the change of "fire txn and never come back to this" in order to + # address RT#107159, but this *MUST* be reevaluated later. + $self->{inactivated} = 1; + $self->{storage}->txn_commit; } sub DESTROY { - my ($dismiss, $storage) = @{$_[0]}; - - return if $dismiss; - - my $exception = $@; - Carp::cluck("A DBIx::Class:: went out of scope without explicit commit/dismiss") - unless $exception; - { - local $@; - eval { $storage->txn_rollback }; - my $rollback_exception = $@; - if($rollback_exception) { - my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION"; - - $storage->throw_exception( - "Transaction aborted: ${exception}. " - . "Rollback failed: ${rollback_exception}" - ) unless $rollback_exception =~ /$exception_class/; - } + return if &detected_reinvoked_destructor; + + return if $_[0]->{inactivated}; + + + # grab it before we've done volatile stuff below + my $current_exception = ( + is_exception $@ + and + ( + ! defined $_[0]->{existing_exception_ref} + or + refaddr( (length ref $@) ? $@ : \$@ ) != refaddr($_[0]->{existing_exception_ref}) + ) + ) + ? $@ + : undef + ; + + + # if our dbh is not ours anymore, the $dbh weakref will go undef + $_[0]->{storage}->_verify_pid unless DBIx::Class::_ENV_::BROKEN_FORK; + return unless defined $_[0]->{dbh}; + + + carp 'A DBIx::Class::Storage::TxnScopeGuard went out of scope without explicit commit or error. Rolling back' + unless defined $current_exception; + + + if ( + my $rollback_exception = $_[0]->{storage}->__delicate_rollback( + defined $current_exception + ? \$current_exception + : () + ) + and + ! defined $current_exception + ) { + carp (join ' ', + "********************* ROLLBACK FAILED!!! ********************", + "\nA rollback operation failed after the guard went out of scope.", + 'This is potentially a disastrous situation, check your data for', + "consistency: $rollback_exception" + ); } + + $@ = $current_exception + if DBIx::Class::_ENV_::UNSTABLE_DOLLARAT; + + # Dummy NEXTSTATE ensuring the all temporaries on the stack are garbage + # collected before leaving this scope. Depending on the code above, this + # may very well be just a preventive measure guarding future modifications + undef; } 1; @@ -53,7 +116,7 @@ __END__ =head1 NAME -DBIx::Class::Storage::TxnScopeGuard +DBIx::Class::Storage::TxnScopeGuard - Scope-based transaction handling =head1 SYNOPSIS @@ -70,20 +133,21 @@ DBIx::Class::Storage::TxnScopeGuard =head1 DESCRIPTION An object that behaves much like L, but hardcoded to do the -right thing with transactions in DBIx::Class. +right thing with transactions in DBIx::Class. =head1 METHODS =head2 new -Creating an instance of this class will start a new transaction. Expects a +Creating an instance of this class will start a new transaction (by +implicitly calling L. Expects a L object as its only argument. =head2 commit Commit the transaction, and stop guarding the scope. If this method is not -called (i.e. an exception is thrown) and this object goes out of scope then -the transaction is rolled back. +called and this object goes out of scope (e.g. an exception is thrown) then +the transaction is rolled back, via L =cut @@ -91,13 +155,15 @@ the transaction is rolled back. L. -=head1 AUTHOR +L by chocolateboy (inspiration for this module) -Ash Berlin, 2008. +=head1 FURTHER QUESTIONS? -Insipred by L by chocolateboy. +Check the list of L. -This module is free software. It may be used, redistributed and/or modified -under the same terms as Perl itself. +=head1 COPYRIGHT AND LICENSE -=cut +This module is free software L +by the L. You can +redistribute it and/or modify it under the same terms as the +L.