| 1 | |
| 2 | my $mplx_trace = 0; |
| 3 | |
| 4 | # vim:ts=4 |
| 5 | { |
| 6 | package DBD::Multiplex; |
| 7 | |
| 8 | require DBI; |
| 9 | require Carp; |
| 10 | |
| 11 | @EXPORT = (); |
| 12 | $VERSION = substr(q$Revision: 1.2 $, 9,-1) -1; |
| 13 | |
| 14 | # $Id: Multiplex.pm,v 1.2 1999/07/29 00:11:57 timbo Exp $ |
| 15 | # |
| 16 | # Copyright (c) 1999, Tim Bunce & Thomas Kishel |
| 17 | # |
| 18 | # You may distribute under the terms of either the GNU General Public |
| 19 | # License or the Artistic License, as specified in the Perl README file. |
| 20 | |
| 21 | $drh = undef; # holds driver handle once initialised |
| 22 | $err = 0; # The $DBI::err value |
| 23 | |
| 24 | sub driver { |
| 25 | return $drh if $drh; |
| 26 | my($class, $attr) = @_; |
| 27 | $class .= "::dr"; |
| 28 | ($drh) = DBI::_new_drh($class, { |
| 29 | 'Name' => 'Multiplex', |
| 30 | 'Version' => $VERSION, |
| 31 | 'Attribution' => 'DBD Multiplex by Tim Bunce & Thomas Kishel', |
| 32 | }); |
| 33 | return $drh; |
| 34 | } |
| 35 | |
| 36 | |
| 37 | # functions for calling a method for each child handle |
| 38 | |
| 39 | sub mplx_do_calls { # 'bottom-level' support function to do the calls |
| 40 | my ($method, $handles, $wantarray, $opts) = (shift,shift,shift,shift); |
| 41 | my $errh = $opts->{errh}; # handle to record error on |
| 42 | my $stop = $opts->{stop_on}||'';# stop on first 'err' or 'ok' else do all |
| 43 | my $trace= $opts->{trace}; |
| 44 | my @results; |
| 45 | my @errors; # sparse array paralleling $results[0..n] |
| 46 | warn "mplx_do_calls $method for (@$handles)" if $trace; |
| 47 | foreach my $h (@$handles) { # child handle |
| 48 | push @results, ($wantarray) ? [ $h->$method(@_) ] |
| 49 | : [ scalar $h->$method(@_) ]; |
| 50 | if (my $err = $h->err) { |
| 51 | my $errstr = $h->errstr; |
| 52 | $errors[ @results-1 ] = [ $err, $errstr ]; |
| 53 | DBI::set_err($errh, $err, $errstr) if $errh; |
| 54 | warn "mplx_do_calls $h->$method ERROR: $err, $errstr" if $trace; |
| 55 | last if $stop eq 'err'; |
| 56 | } |
| 57 | else { |
| 58 | warn "mplx_do_calls $h->$method OK: @{ $results[-1] }" if $trace; |
| 59 | last if $stop eq 'ok'; |
| 60 | } |
| 61 | } |
| 62 | return (\@results, \@errors); |
| 63 | } |
| 64 | |
| 65 | # XXX need variants/flags for |
| 66 | # - call-each-till-first-success-then-stop |
| 67 | # - call-all-return-first-success-else-error |
| 68 | # - call-all-return-most-common-result (eg three-way-voting etc) |
| 69 | # In some cases the default behaviour may depend on the method being called. |
| 70 | # In others the application may want to override that for specific cases |
| 71 | # (using \%attrib) |
| 72 | sub mplx_method_all { |
| 73 | my $method = shift; |
| 74 | my $ph = shift; |
| 75 | my $handles = $ph->{mplx_h} || die; |
| 76 | |
| 77 | my %opts = ( errh => $ph, stop_on => 'err', trace => $mplx_trace ); |
| 78 | |
| 79 | my ($results, $errors) |
| 80 | = mplx_do_calls($method, $handles, wantarray, \%opts, @_); |
| 81 | |
| 82 | my $result = $results->[0]; # pick results to return |
| 83 | return $result->[0] unless wantarray; |
| 84 | return @$result; |
| 85 | } |
| 86 | |
| 87 | } |
| 88 | |
| 89 | |
| 90 | |
| 91 | { package DBD::Multiplex::dr; # ====== DRIVER ====== |
| 92 | $imp_data_size = 0; |
| 93 | |
| 94 | sub connect { my ($drh, $dsn, $user, $auth, $attr) = @_; |
| 95 | |
| 96 | # XXX parse $dsn and make multiple connects |
| 97 | # need to define good syntax |
| 98 | my $dbh1 = DBI->connect($dsn, $user, $auth, $attr); |
| 99 | return DBI::set_err($drh, $DBI::err, $DBI::errstr) unless $dbh1; |
| 100 | |
| 101 | my ($this) = DBI::_new_dbh($drh, { |
| 102 | Name => $dsn, |
| 103 | User => $user, |
| 104 | mplx_h => [ $dbh1 ], |
| 105 | }); |
| 106 | |
| 107 | return $this; |
| 108 | } |
| 109 | |
| 110 | sub disconnect_all { } |
| 111 | sub DESTROY { } |
| 112 | } |
| 113 | |
| 114 | |
| 115 | |
| 116 | { package DBD::Multiplex::db; # ====== DATABASE ====== |
| 117 | $imp_data_size = 0; |
| 118 | |
| 119 | use strict; |
| 120 | |
| 121 | sub prepare { |
| 122 | my $dbh = shift; |
| 123 | my ($statement, $attribs) = @_; |
| 124 | |
| 125 | my $handles = $dbh->{mplx_h} || die; |
| 126 | my %opts = ( errh => $dbh ); |
| 127 | my ($results, $errors) |
| 128 | = DBD::Multiplex::mplx_do_calls('prepare', $handles, wantarray, \%opts, @_); |
| 129 | return if @$errors; |
| 130 | |
| 131 | my ($outer, $sth) = DBI::_new_sth($dbh, { |
| 132 | 'Statement' => $statement, |
| 133 | mplx_h => [ map { $_->[0] } @$results ], |
| 134 | }); |
| 135 | $outer; |
| 136 | } |
| 137 | |
| 138 | # XXX replace this with dynamic info from updated DBI |
| 139 | # XXX needs expanding manually in the short term |
| 140 | use subs qw(FETCH STORE DESTROY); |
| 141 | |
| 142 | sub AUTOLOAD { |
| 143 | my $method = $DBD::Multiplex::db::AUTOLOAD; |
| 144 | $method =~ s/^DBD::Multiplex::db:://; |
| 145 | warn "db AUTOLOAD $method(@_)" if $mplx_trace; |
| 146 | |
| 147 | my @results = (wantarray) |
| 148 | ? ( DBD::Multiplex::mplx_method_all($method, @_)) |
| 149 | : (scalar DBD::Multiplex::mplx_method_all($method, @_)); |
| 150 | |
| 151 | return $results[0] unless wantarray; |
| 152 | return @results; |
| 153 | } |
| 154 | |
| 155 | } |
| 156 | |
| 157 | |
| 158 | { package DBD::Multiplex::st; # ====== STATEMENT ====== |
| 159 | $imp_data_size = 0; |
| 160 | use strict; |
| 161 | |
| 162 | # XXX replace this with dynamic info from updated DBI |
| 163 | # XXX needs expanding manually in the short term |
| 164 | use subs qw(execute fetch fetchrow_arrayref finish STORE FETCH DESTROY); |
| 165 | |
| 166 | sub AUTOLOAD { |
| 167 | my $method = $DBD::Multiplex::st::AUTOLOAD; |
| 168 | $method =~ s/^DBD::Multiplex::st:://; |
| 169 | warn "st AUTOLOAD $method(@_)" if $mplx_trace; |
| 170 | |
| 171 | my @results = (wantarray) |
| 172 | ? ( DBD::Multiplex::mplx_method_all($method, @_)) |
| 173 | : (scalar DBD::Multiplex::mplx_method_all($method, @_)); |
| 174 | |
| 175 | return $results[0] unless wantarray; |
| 176 | return @results; |
| 177 | } |
| 178 | |
| 179 | } |
| 180 | |
| 181 | 1; |
| 182 | __END__ |
| 183 | |
| 184 | =head1 NAME |
| 185 | |
| 186 | DBD::Multiplex - A DBI driver multiplexer |
| 187 | |
| 188 | =head1 SYNOPSIS |
| 189 | |
| 190 | use DBI; |
| 191 | |
| 192 | $dbh = DBI->connect("dbi:Multiplex:dsn", $user, $passwd); |
| 193 | |
| 194 | # See the DBI module documentation for full details |
| 195 | |
| 196 | =head1 DESCRIPTION |
| 197 | |
| 198 | To be written |
| 199 | |
| 200 | =cut |