[ViewVC] Diff of: cvs/cvsroot/Coro/Coro.pm

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.241 by root, Thu Dec 4 04:31:41 2008 UTC vs.
Revision 1.247 by root, Mon Dec 15 02:07:11 2008 UTC

 package Coro;
 use strict qw(vars subs);
 no warnings "uninitialized";
+use Guard ();
 use Coro::State;
 use base qw(Coro::State Exporter);
 our $idle;    # idle handler
 our $main;    # main coroutine
 our $current; # current coroutine
-our $VERSION = 5.11;
+our $VERSION = 5.13;
 our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
 our %EXPORT_TAGS = (
       prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
 );
 =item terminate [arg...]
 Terminates the current coroutine with the given status values (see L<cancel>).
+=item Coro::on_enter BLOCK, Coro::on_leave BLOCK
+These function install enter and leave winders in the current scope. The
+enter block will be executed when on_enter is called and whenever the
+current coroutine is re-entered by the scheduler, while the leave block is
+executed whenever the current coroutine is blocked by the scheduler, and
+also when the containing scope is exited (by whatever means, be it exit,
+die, last etc.).
+I<Neither invoking the scheduler, nor exceptions, are allowed within those
+BLOCKs>. That means: do not even think about calling C<die> without an
+eval, and do not even think of entering the scheduler in any way.
+Since both BLOCKs are tied to the current scope, they will automatically
+be removed when the current scope exits.
+These functions implement the same concept as C<dynamic-wind> in scheme
+does, and are useful when you want to localise some resource to a specific
+coroutine.
+They slow down coroutine switching considerably for coroutines that use
+them (But coroutine switching is still reasonably fast if the handlers are
+fast).
+These functions are best understood by an example: The following function
+will change the current timezone to "Antarctica/South_Pole", which
+requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>,
+which remember/change the current timezone and restore the previous
+value, respectively, the timezone is only changes for the coroutine that
+installed those handlers.
+   use POSIX qw(tzset);
+   async {
+      my $old_tz; # store outside TZ value here
+      Coro::on_enter {
+         $old_tz = $ENV{TZ}; # remember the old value
+         $ENV{TZ} = "Antarctica/South_Pole";
+         tzset; # enable new value
+      };
+      Coro::on_leave {
+         $ENV{TZ} = $old_tz;
+         tzset; # restore old value
+      };
+      # at this place, the timezone is Antarctica/South_Pole,
+      # without disturbing the TZ of any other coroutine.
+   };
+This can be used to localise about any resource (locale, uid, current
+working directory etc.) to a block, despite the existance of other
+coroutines.
 =item killall
-Kills/terminates/cancels all coroutines except the currently running
+Kills/terminates/cancels all coroutines except the currently running one.
-one. This is useful after a fork, either in the child or the parent, as
-usually only one of them should inherit the running coroutines.
-Note that while this will try to free some of the main programs resources,
+Note that while this will try to free some of the main interpreter
+resources if the calling coroutine isn't the main coroutine, but one
-you cannot free all of them, so if a coroutine that is not the main
+cannot free all of them, so if a coroutine that is not the main coroutine
-program calls this function, there will be some one-time resource leak.
+calls this function, there will be some one-time resource leak.
 =cut
 sub killall {
    for (Coro::State::list) {
 would cause a deadlock unless there is an idle handler that wakes up some
 coroutines.
 =item my $guard = Coro::guard { ... }
-This creates and returns a guard object. Nothing happens until the object
+This function still exists, but is deprecated. Please use the
-gets destroyed, in which case the codeblock given as argument will be
+C<Guard::guard> function instead.
-executed. This is useful to free locks or other resources in case of a
-runtime error or when the coroutine gets canceled, as in both cases the
-guard block will be executed. The guard object supports only one method,
-C<< ->cancel >>, which will keep the codeblock from being executed.
-Example: set some flag and clear it again when the coroutine gets canceled
-or the function returns:
-   sub do_something {
-      my $guard = Coro::guard { $busy = 0 };
-      $busy = 1;
-      # do something that requires $busy to be true
-   }
 =cut
-sub guard(&) {
+BEGIN { *guard = \&Guard::guard }
-   bless \(my $cb = $_[0]), "Coro::guard"
-}
-sub Coro::guard::cancel {
-   ${$_[0]} = sub { };
-}
-sub Coro::guard::DESTROY {
-   ${$_[0]}->();
-}
 =item unblock_sub { ... }
 This utility function takes a BLOCK or code reference and "unblocks" it,
 returning a new coderef. Unblocking means that calling the new coderef

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing cvsroot/Coro/Coro.pm (file contents): Revision 1.241 by root, Thu Dec 4 04:31:41 2008 UTC vs. Revision 1.247 by root, Mon Dec 15 02:07:11 2008 UTC

Diff Legend

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.241 by root, Thu Dec 4 04:31:41 2008 UTC vs.
Revision 1.247 by root, Mon Dec 15 02:07:11 2008 UTC