--- Coro/Coro/Semaphore.pm	2001/10/03 01:09:57	1.22
+++ Coro/Coro/Semaphore.pm	2006/01/25 21:43:58	1.52
@@ -33,11 +33,11 @@
 
 package Coro::Semaphore;
 
-no warnings qw(uninitialized);
+BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") }
 
 use Coro ();
 
-$VERSION = 0.51;
+$VERSION = 1.8;
 
 =item new [inital count]
 
@@ -57,6 +57,11 @@
 Decrement the counter, therefore "locking" the semaphore. This method
 waits until the semaphore is available if the counter is zero.
 
+=item $status = $sem->timed_down($timeout)
+
+Like C<down>, but returns false if semaphore couldn't be acquired within
+$timeout seconds, otherwise true.
+
 =cut
 
 sub down {
@@ -67,6 +72,29 @@
    --$_[0][0];
 }
 
+sub timed_down {
+   require Coro::Timer;
+   my $timeout = Coro::Timer::timeout($_[1]);
+
+   while ($_[0][0] <= 0) {
+      push @{$_[0][1]}, $Coro::current;
+      Coro::schedule;
+      if ($timeout) {
+         # ugly as hell. slow, too, btw!
+         for (0..$#{$_[0][1]}) {
+            if ($_[0][1][$_] == $Coro::current) {
+               splice @{$_[0][1]}, $_, 1;
+               return;
+            }
+         }
+         die;
+      }
+   }
+
+   --$_[0][0];
+   return 1;
+}
+
 =item $sem->up
 
 Unlock the semaphore again.
@@ -111,27 +139,38 @@
 This method calls C<down> and then creates a guard object. When the guard
 object is destroyed it automatically calls C<up>.
 
+=item $guard = $sem->timed_guard($timeout)
+
+Like C<guard>, but returns undef if semaphore couldn't be acquired within
+$timeout seconds, otherwise the guard object.
+
 =cut
 
 sub guard {
    &down;
    # double indirection because bless works on the referenced
    # object, not (only) on the reference itself.
-   bless \\$_[0], Coro::Semaphore::Guard::;
+   bless \\$_[0], Coro::Semaphore::guard::;
 }
 
-sub Coro::Semaphore::Guard::DESTROY {
-   &up(${${$_[0]}});
+sub timed_guard {
+   &timed_down
+      ? bless \\$_[0], Coro::Semaphore::guard::
+      : ();
 }
 
-1;
+sub Coro::Semaphore::guard::DESTROY {
+   &up(${${$_[0]}});
+}
 
 =back
 
 =head1 AUTHOR
 
- Marc Lehmann <pcg@goof.com>
- http://www.goof.com/pcg/marc/
+ Marc Lehmann <schmorp@schmorp.de>
+ http://home.schmorp.de/
 
 =cut
 
+1
+