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package FS::Misc::Savepoint;
use strict;
use warnings;
use Exporter;
use vars qw( @ISA @EXPORT @EXPORT_OK );
@ISA = qw( Exporter );
@EXPORT = qw( savepoint_create savepoint_release savepoint_rollback );
use FS::UID qw( dbh );
use Carp qw( croak );
=head1 NAME
FS::Misc::Savepoint - Provides methods for SQL Savepoints
=head1 SYNOPSIS
use FS::Misc::Savepoint;
# Only valid within a transaction
local $FS::UID::AutoCommit = 0;
savepoint_create( 'savepoint_label' );
my $error_msg = do_some_things();
if ( $error_msg ) {
savepoint_rollback_and_release( 'savepoint_label' );
} else {
savepoint_release( 'savepoint_label' );
}
=head1 DESCRIPTION
Provides methods for SQL Savepoints
Using a savepoint allows for a partial roll-back of SQL statements without
forcing a rollback of the entire enclosing transaction.
=head1 METHODS
=over 4
=item savepoint_create LABEL
=item savepoint_create { label => LABEL, dbh => DBH }
Executes SQL to create a savepoint named LABEL.
Savepoints cannot work while AutoCommit is enabled.
Savepoint labels must be valid sql identifiers. If your choice of label
would not make a valid column name, it probably will not make a valid label.
Savepint labels must be unique within the transaction.
=cut
sub savepoint_create {
my %param = _parse_params( @_ );
$param{dbh}->do("SAVEPOINT $param{label}")
or die $param{dbh}->errstr;
}
=item savepoint_release LABEL
=item savepoint_release { label => LABEL, dbh => DBH }
Release the savepoint - preserves the SQL statements issued since the
savepoint was created, but does not commit the transaction.
The savepoint label is freed for future use.
=cut
sub savepoint_release {
my %param = _parse_params( @_ );
$param{dbh}->do("RELEASE SAVEPOINT $param{label}")
or die $param{dbh}->errstr;
}
=item savepoint_rollback LABEL
=item savepoint_rollback { label => LABEL, dbh => DBH }
Roll back the savepoint - forgets all SQL statements issues since the
savepoint was created, but does not commit or roll back the transaction.
The savepoint still exists. Additional statements may be executed,
and savepoint_rollback called again.
=cut
sub savepoint_rollback {
my %param = _parse_params( @_ );
$param{dbh}->do("ROLLBACK TO SAVEPOINT $param{label}")
or die $param{dbh}->errstr;
}
=item savepoint_rollback_and_release LABEL
=item savepoint_rollback_and_release { label => LABEL, dbh => DBH }
Rollback and release the savepoint
=cut
sub savepoint_rollback_and_release {
savepoint_rollback( @_ );
savepoint_release( @_ );
}
=back
=head1 METHODS - Internal
=over 4
=item _parse_params
Create %params from function input
Basic savepoint label validation
Complain when trying to use savepoints without disabling AutoCommit
=cut
sub _parse_params {
my %param = ref $_[0] ? %{ $_[0] } : ( label => $_[0] );
$param{dbh} ||= dbh;
# Savepoints may be any valid SQL identifier up to 64 characters
$param{label} =~ /^\w+$/
or croak sprintf(
'Invalid savepont label(%s) - use only numbers, letters, _',
$param{label}
);
croak sprintf( 'Savepoint(%s) failed - AutoCommit=1', $param{label} )
if $FS::UID::AutoCommit;
%param;
}
=back
=head1 BUGS
=head1 SEE ALSO
=cut
1;
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