but don't break Pg cursors in the process, #28895

[freeside.git] / FS / FS / Cursor.pm

diff --git a/FS/FS/Cursor.pm b/FS/FS/Cursor.pm
index f3bc1e2..f6d8816 100644 (file)
--- a/FS/FS/Cursor.pm
+++ b/FS/FS/Cursor.pm
@@ -2,12 +2,12 @@ package FS::Cursor;
 
 use strict;
 use vars qw($DEBUG $buffer);
-use base qw( Exporter );
-use FS::Record qw(qsearch dbdef dbh);
-use Data::Dumper;
+use FS::Record;
+use FS::UID qw(myconnect driver_name);
 use Scalar::Util qw(refaddr);
 
-$DEBUG = 0;
+$DEBUG = 2;
+
 # this might become a parameter at some point, but right now, you can
 # "local $FS::Cursor::buffer = X;"
 $buffer = 200;
@@ -39,24 +39,38 @@ and returns an FS::Cursor object to fetch the rows one at a time.
 sub new {
   my $class = shift;
   my $q = FS::Record::_query(@_); # builds the statement and parameter list
+  my $dbh = myconnect();
 
   my $self = {
     query => $q,
     class => 'FS::' . ($q->{table} || 'Record'),
     buffer => [],
+    dbh   => $dbh,
+    position => 0, # for mysql
   };
   bless $self, $class;
 
   # the class of record object to return
   $self->{class} = "FS::".($q->{table} || 'Record');
 
+  # save for later, so forked children will not destroy me when they exit
+  $self->{pid} = $$;
+
   $self->{id} = sprintf('cursor%08x', refaddr($self));
-  my $statement = "DECLARE ".$self->{id}." CURSOR FOR ".$q->{statement};
 
-  my $dbh = dbh;
+  my $statement;
+  if ( driver_name() eq 'Pg' ) {
+    $statement = "DECLARE ".$self->{id}." CURSOR FOR ".$q->{statement};
+  } elsif ( driver_name() eq 'mysql' ) {
+    # build a cursor from scratch
+    $statement = "CREATE TEMPORARY TABLE $self->{id} 
+      (rownum INT AUTO_INCREMENT, PRIMARY KEY (rownum))
+      $q->{statement}";
+  }
+
   my $sth = $dbh->prepare($statement)
     or die $dbh->errstr;
-  my $bind = 0;
+  my $bind = 1;
   foreach my $value ( @{ $q->{value} } ) {
     my $bind_type = shift @{ $q->{bind_type} };
     $sth->bind_param($bind++, $value, $bind_type );
@@ -64,7 +78,14 @@ sub new {
 
   $sth->execute or die $sth->errstr;
 
-  $self->{fetch} = $dbh->prepare("FETCH FORWARD $buffer FROM ".$self->{id});
+  if ( driver_name() eq 'Pg' ) {
+    $self->{fetch} = $dbh->prepare("FETCH FORWARD $buffer FROM ".$self->{id});
+  } elsif ( driver_name() eq 'mysql' ) {
+    # make sure we're not holding any locks on the tables mentioned
+    # in the query
+    $dbh->commit if driver_name() eq 'mysql';
+    $self->{fetch} = $dbh->prepare("SELECT * FROM $self->{id} ORDER BY rownum LIMIT ?, $buffer");
+  }
 
   $self;
 }
@@ -95,12 +116,28 @@ sub fetch {
 sub refill {
   my $self = shift;
   my $sth = $self->{fetch};
+  $sth->bind_param(1, $self->{position}) if driver_name() eq 'mysql';
   $sth->execute or die $sth->errstr;
   my $result = $self->{fetch}->fetchall_arrayref( {} );
   $self->{buffer} = $result;
+  $self->{position} += $sth->rows;
   scalar @$result;
 }
 
+sub DESTROY {
+  my $self = shift;
+  return unless $self->{pid} eq $$;
+  if ( driver_name() eq 'Pg' ) {
+    $self->{dbh}->do('CLOSE '. $self->{id})
+      or die $self->{dbh}->errstr; # clean-up the cursor in Pg
+  } elsif ( driver_name() eq 'mysql' ) {
+    # nothing; the temporary table will evaporate when the 
+    # session closes.
+  }
+  $self->{dbh}->rollback;
+  $self->{dbh}->disconnect;
+}
+
 =back
 
 =head1 TO DO
@@ -109,7 +146,14 @@ Replace all uses of qsearch with this.
 
 =head1 BUGS
 
-Doesn't support MySQL.
+MySQL doesn't support cursors in interactive sessions, only in stored 
+procedures, so we implement our own.  This has not been extensively tested.
+
+The cursor will close prematurely if any code issues a rollback/commit. If
+you need protection against this use qsearch or fork and get a new dbh
+handle.
+Normally this issue will represent itself this message.
+ERROR: cursor "cursorXXXXXXX" does not exist.
 
 =head1 SEE ALSO