--- Coro-Mysql/Mysql.pm	2010/08/31 14:42:28	1.5
+++ Coro-Mysql/Mysql.pm	2011/02/17 02:06:55	1.10
@@ -22,8 +22,9 @@
 
 =head2 CAVEAT
 
-Note that this module must be linked against exactly the same
-F<libmysqlclient> library as DBD::mysql, otherwise it will not work.
+Note that this module must be linked against exactly the same (shared,
+possibly not working with all OSes) F<libmysqlclient> library as
+DBD::mysql, otherwise it will not work.
 
 Also, while this module makes database handles non-blocking, you still
 cannot run multiple requests in parallel on the same database handle. If
@@ -35,8 +36,8 @@
 can freely share the database handles between threads, of course.
 
 Also, this module uses a number of "unclean" techniques (patching an
-internal libmysql structure for one thing) and was hacked within a few
-hours on a long flight to Malaysia.
+internal libmysql structure for one thing) and was initially hacked within
+a few hours on a long flight to Malaysia.
 
 It does, however, check whether it indeed got the structure layout
 correct, so you should expect perl exceptions or early crashes as opposed
@@ -46,13 +47,16 @@
 
 This module is implemented in XS, and as long as mysqld replies quickly
 enough, it adds no overhead to the standard libmysql communication
-routines (which are very badly written, btw.).
+routines (which are very badly written, btw.). In fact, since it has a
+more efficient buffering and allows requests to run in parallel, it often
+decreases the actual time to run many queries considerably.
 
 For very fast queries ("select 0"), this module can add noticable overhead
-(around 15%) as it tries to switch to other coroutines when mysqld doesn't
-deliver the data instantly.
+(around 15%, 7% when EV can be used) as it tries to switch to other
+coroutines when mysqld doesn't deliver the data immediately, although,
+again, when running queries in parallel, they will usually execute faster.
 
-For most types of queries, there will be no overhead, especially on
+For most types of queries, there will be no extra latency, especially on
 multicore systems where your perl process can do other things while mysqld
 does its stuff.
 
@@ -63,6 +67,13 @@
 pipes (windows) and shared memory (also windows). No support for these
 connection types is planned, either.
 
+=head1 CANCELLATION
+
+Cancelling a thread that is within a mysql query will likely make the
+handle unusable. As far as Coro::Mysql is concerned, the handle can be
+safely destroyed, but it's not clear how mysql itself will react to a
+cancellation.
+
 =head1 FUNCTIONS
 
 Coro::Mysql offers a single user-accessible function:
@@ -80,7 +91,9 @@
 use Carp qw(croak);
 
 use Guard;
-use Coro::Handle ();
+use AnyEvent ();
+use Coro ();
+use Coro::AnyEvent (); # not necessary with newer Coro versions
 
 # we need this extra indirection, as Coro doesn't support
 # calling SLF-like functions via call_sv.
@@ -89,7 +102,7 @@
 sub writable { &Coro::Handle::FH::writable }
 
 BEGIN {
-   our $VERSION = '1.01';
+   our $VERSION = '1.02';
 
    require XSLoader;
    XSLoader::load Coro::Mysql::, $VERSION;
@@ -108,18 +121,26 @@
 returned unchanged. That means it is harmless when applied to database
 handles of other databases.
 
+It is also safe to pass C<undef>, so code like this is works as expected:
+
+   my $dbh = DBI->connect ($database, $user, $pass)->Coro::Mysql::unblock
+      or die $DBI::errstr;
+
 =cut
 
 sub unblock {
    my ($DBH) = @_;
 
-   if ($DBH->{Driver}{Name} eq "mysql") {
+   if ($DBH && $DBH->{Driver}{Name} eq "mysql") {
       my $sock = $DBH->{sock};
 
       open my $fh, "+>&" . $DBH->{sockfd}
          or croak "Coro::Mysql unable to clone mysql fd";
 
-      $fh = Coro::Handle::unblock $fh;
+      if (AnyEvent::detect ne "AnyEvent::Impl::EV" || !_use_ev) {
+         require Coro::Handle;
+         $fh = Coro::Handle::unblock ($fh);
+      }
 
       _patch $sock, $DBH->{sockfd}, $fh, tied ${$fh};
    }
@@ -146,7 +167,7 @@
    sub with_db($$$&) {
       my ($database, $user, $pass, $cb) = @_;
 
-      my $dbh = Coro::Mysql::unblock DBI->connect ($database, $user, $pass)
+      my $dbh = DBI->connect ($database, $user, $pass)->Coro::Mysql::unblock
          or die $DBI::errstr;
 
       Coro::on_enter { $PApp::SQL::DBH = $dbh };