+##############################################################################
+
+=method begin_work
+
+ $txn = $object->begin_work(%options);
+ $object->begin_work(%options);
+
+Begin a new transaction. Returns a L<File::KDBX::Transaction> object that can be scoped to ensure a rollback
+occurs if exceptions are thrown. Alternatively, if called in void context, there will be no
+B<File::KDBX::Transaction> and it is instead your responsibility to call L</commit> or L</rollback> as
+appropriate. It is undefined behavior to call these if a B<File::KDBX::Transaction> exists. Recursive
+transactions are allowed.
+
+Signals created during a transaction are delayed until all transactions are resolved. If the outermost
+transaction is committed, then the signals are de-duplicated and delivered. Otherwise the signals are dropped.
+This means that the KDBX database will not fix broken references or mark itself dirty until after the
+transaction is committed.
+
+How it works: With the beginning of a transaction, a snapshot of the object is created. In the event of
+a rollback, the object's data is replaced with data from the snapshot.
+
+By default, the snapshot is shallow (i.e. does not include subroups, entries or historical entries). This
+means that only modifications to the object itself (its data, fields, strings, etc.) are atomic; modifications
+to subroups etc., including adding or removing items, are auto-committed instantly and will persist regardless
+of the result of the pending transaction. You can override this for groups, entries and history independently
+using options:
+
+=for :list
+* C<entries> - If set, snapshot entries within a group, deeply (default: false)
+* C<groups> - If set, snapshot subroups within a group, deeply (default: false)
+* C<history> - If set, snapshot historical entries within an entry (default: false)
+
+For example, if you begin a transaction on a group object using the C<entries> option, like this:
+
+ $group->begin_work(entries => 1);
+
+Then if you modify any of the group's entries OR add new entries OR delete entries, all of that will be undone
+if the transaction is rolled back. With a default-configured transaction, however, changes to entries are kept
+even if the transaction is rolled back.
+
+=cut
+
+sub begin_work {
+ my $self = shift;
+
+ if (defined wantarray) {
+ require File::KDBX::Transaction;
+ return File::KDBX::Transaction->new($self, @_);
+ }
+
+ my %args = @_;
+ my $orig = $args{snapshot} // do {
+ my $c = $self->clone(
+ entries => $args{entries} // 0,
+ groups => $args{groups} // 0,
+ history => $args{history} // 0,
+ );
+ $c->{entries} = $self->{entries} if !$args{entries};
+ $c->{groups} = $self->{groups} if !$args{groups};
+ $c->{history} = $self->{history} if !$args{history};
+ $c;
+ };
+
+ my $id = Hash::Util::FieldHash::id($orig);
+ _save_references($id, $self, $orig);
+
+ $self->_signal_begin_work;
+
+ push @{$self->_txns}, $orig;
+}
+
+=method commit
+
+ $object->commit;
+
+Commit a transaction, making updates to C<$object> permanent. Returns itself to allow method chaining.
+
+=cut
+
+sub commit {
+ my $self = shift;
+ my $orig = pop @{$self->_txns} or return $self;
+ $self->_commit($orig);
+ my $signals = $self->_signal_commit;
+ $self->_signal_send($signals) if !$self->_in_txn;
+ return $self;
+}
+
+=method rollback
+
+ $object->rollback;
+
+Roll back the most recent transaction, throwing away any updates to the L</object> made since the transaction
+began. Returns itself to allow method chaining.
+
+=cut
+
+sub rollback {
+ my $self = shift;
+
+ my $orig = pop @{$self->_txns} or return $self;
+
+ my $id = Hash::Util::FieldHash::id($orig);
+ _restore_references($id, $orig);
+
+ $self->_signal_rollback;
+
+ return $self;
+}
+
+# Get whether or not there is at least one pending transaction.
+sub _in_txn { scalar @{$_[0]->_txns} }
+
+# Get an array ref of pending transactions.
+sub _txns { $TXNS{$_[0]} //= [] }
+
+# The _commit hook notifies subclasses that a commit has occurred.
+sub _commit { die 'Not implemented' }
+
+# Get a reference to an object that represents an object's committed state. If there is no pending
+# transaction, this is just $self. If there is a transaction, this is the snapshot take before the transaction
+# began. This method is private because it provides direct access to the actual snapshot. It is important that
+# the snapshot not be changed or a rollback would roll back to an altered state.
+# This is used by File::KDBX::Dumper::XML so as to not dump uncommitted changes.
+sub _committed {
+ my $self = shift;
+ my ($orig) = @{$self->_txns};
+ return $orig // $self;
+}
+
+# In addition to cloning an object when beginning work, we also keep track its hashrefs and arrayrefs
+# internally so that we can restore to the very same structures in the case of a rollback.
+sub _save_references {
+ my $id = shift;
+ my $self = shift;
+ my $orig = shift;
+
+ if (is_plain_arrayref($orig)) {
+ for (my $i = 0; $i < @$orig; ++$i) {
+ _save_references($id, $self->[$i], $orig->[$i]);
+ }
+ $REFS{$id}{Hash::Util::FieldHash::id($orig)} = $self;
+ }
+ elsif (is_plain_hashref($orig) || (blessed $orig && $orig->isa(__PACKAGE__))) {
+ for my $key (keys %$orig) {
+ _save_references($id, $self->{$key}, $orig->{$key});
+ }
+ $REFS{$id}{Hash::Util::FieldHash::id($orig)} = $self;
+ }
+}
+
+# During a rollback, copy data from the snapshot back into the original internal structures.
+sub _restore_references {
+ my $id = shift;
+ my $orig = shift // return;
+ my $self = delete $REFS{$id}{Hash::Util::FieldHash::id($orig) // ''} // return $orig;
+
+ if (is_plain_arrayref($orig)) {
+ @$self = map { _restore_references($id, $_) } @$orig;
+ }
+ elsif (is_plain_hashref($orig) || (blessed $orig && $orig->isa(__PACKAGE__))) {
+ for my $key (keys %$orig) {
+ # next if is_ref($orig->{$key}) &&
+ # (Hash::Util::FieldHash::id($self->{$key}) // 0) == Hash::Util::FieldHash::id($orig->{$key});
+ $self->{$key} = _restore_references($id, $orig->{$key});
+ }
+ }
+
+ return $self;
+}
+
+##############################################################################
+
+sub _signal {
+ my $self = shift;
+ my $type = shift;
+
+ if ($self->_in_txn) {
+ my $stack = $self->_signal_stack;
+ my $queue = $stack->[-1];
+ push @$queue, [$type, @_];
+ }
+
+ $self->_signal_send([[$type, @_]]);
+
+ return $self;
+}
+
+sub _signal_stack { $SIGNALS{$_[0]} //= [] }
+
+sub _signal_begin_work {
+ my $self = shift;
+ push @{$self->_signal_stack}, [];
+}
+
+sub _signal_commit {
+ my $self = shift;
+ my $signals = pop @{$self->_signal_stack};
+ my $previous = $self->_signal_stack->[-1] // [];
+ push @$previous, @$signals;
+ return $previous;
+}
+
+sub _signal_rollback {
+ my $self = shift;
+ pop @{$self->_signal_stack};
+}
+
+sub _signal_send {
+ my $self = shift;
+ my $signals = shift // [];
+
+ my $kdbx = $KDBX{$self} or return;
+
+ # de-duplicate, keeping the most recent signal for each type
+ my %seen;
+ my @signals = grep { !$seen{$_->[0]}++ } reverse @$signals;
+
+ for my $sig (reverse @signals) {
+ $kdbx->_handle_signal($self, @$sig);
+ }
+}
+
+##############################################################################
+
projects / chaz / p5-File-KDBX / blobdiff