From b317fbd689b5ef362192025f797da0d451105f8e Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 7 Jan 2013 01:37:28 +0000
Subject: [PATCH] wip, transaction fixup

---
 cgi-auth-hybrid.pm | 49 ++++++++++++++++++++++++++++++----------------
 commit-test.pl     | 25 +++++++++++++++++++++++
 test.cgi           |  2 --
 3 files changed, 57 insertions(+), 19 deletions(-)
 create mode 100755 commit-test.pl

diff --git a/cgi-auth-hybrid.pm b/cgi-auth-hybrid.pm
index f22083a..0617881 100644
--- a/cgi-auth-hybrid.pm
+++ b/cgi-auth-hybrid.pm
@@ -209,14 +209,14 @@ sub _dbopen ($) {
     die "$dsn $! ?" unless $dbh;
     $v->{Dbh} = $dbh;
 
-    $dbh->do("BEGIN");
-
     eval {
-	$dbh->do("CREATE TABLE $v->{S}{assocdb_table} (".
-		 " associdh VARCHAR PRIMARY KEY,".
-                 " username VARCHAR,".
-		 " last INTEGER NOT NULL".
-		 ")");
+	$r->_db_transaction(sub {
+	    $dbh->do("CREATE TABLE $v->{S}{assocdb_table} (".
+		     " associdh VARCHAR PRIMARY KEY,".
+		     " username VARCHAR,".
+		     " last INTEGER NOT NULL".
+		     ")");
+        });
     };
     return $dbh;
 }
@@ -228,6 +228,29 @@ sub disconnect ($) {
     $dbh->disconnect();
 }
 
+sub _db_transaction ($$) {
+    my ($r, $fn) = @_;
+    my $retries = 10;
+    my $rv;
+    my $dbh = $v->{Dbh};
+    for (;;) {
+	if (!eval {
+	    $rv = $fn->();
+	    1;
+	}) {
+	    { local ($@); $dbh->rollback(); }
+	    die $@;
+	}
+	if (eval {
+	    $dbh->commit();
+	    1;
+	}) {
+	    return $rv;
+	}
+	die $@ if !--$retries;
+    }
+}
+
 #---------- request object methods ----------
 
 sub new_request {
@@ -550,16 +573,8 @@ sub check_divert ($) {
         return $r->{Divert};
     }
     my $dbh = $r->{Dbh};
-    $dbh->do("BEGIN");
-    if (!eval {
-        $divert = $r->_check_divert_core();
-        1;
-    }) {
-        $dbh->do("ABORT");
-        die $@;
-    }
-    $r->{Divert} = $divert;
-    $dbh->do("COMMIT");
+    $r->{Divert} = $r->_db_transaction(sub { $r->_check_divert_core(); });
+    $dbh->commit();
     return $divert;
 }
 
diff --git a/commit-test.pl b/commit-test.pl
new file mode 100755
index 0000000..69a0640
--- /dev/null
+++ b/commit-test.pl
@@ -0,0 +1,25 @@
+#!/usr/bin/perl -w
+
+use warnings;
+use strict;
+use DBI;
+
+my $dsn = "dbi:SQLite:dbname=test.db";
+my $dbh = DBI->connect($dsn, '','', { 
+                            AutoCommit => 0, RaiseError => 1,
+                        });
+
+foreach my $v (@ARGV) {
+    if (!eval {
+	if ($v eq 'bw') { $dbh->begin_work or die; }
+	elsif ($v eq 'rb') { $dbh->rollback or die; }
+	elsif ($v eq 'ci') { $dbh->commit or die; }
+	elsif ($v eq 'dc') { $dbh->disconnect or die; }
+	elsif ($v eq 'ct') { $dbh->do('CREATE TABLE t (f TEXT)') or die; }
+	elsif ($v eq 'i') { $dbh->do('INSERT INTO t VALUES ("x")') or die; }
+	else { die; }
+	1;
+    }) {
+	warn $@;
+    }
+}
diff --git a/test.cgi b/test.cgi
index b929551..c869327 100755
--- a/test.cgi
+++ b/test.cgi
@@ -7,8 +7,6 @@ use CGI::Auth::Hybrid;
 
 my $dump = "$ENV{'CAHTEST_HOME'}/dump";
 
-#require 'cgi-auth-hybrid.pm';
-
 my $verifier = CGI::Auth::Hybrid->new_verifier(
    assocdb_path => "$dump/assoc.db",
    username_password_ok => sub { my ($c,$r,$u,$p)=@_; return $p eq 'sesame'; },
-- 
2.30.2