NAME

Mail::SpamAssassin::Timeout - safe, reliable timeouts in perl

SYNOPSIS

# non-timeout code...

my $t = Mail::SpamAssassin::Timeout->new({ secs => 5, deadline => $when });

$t->run(sub {
    # code to run with a 5-second timeout...
});

if ($t->timed_out()) {
    # do something...
}

# more non-timeout code...

DESCRIPTION

This module provides a safe, reliable and clean API to provide alarm(2)-based timeouts for perl code.

Note that $SIG{ALRM} is used to provide the timeout, so this will not interrupt out-of-control regular expression matches.

Nested timeouts are supported.

PUBLIC METHODS

my $t = Mail::SpamAssassin::Timeout->new({ ... options ... });

Constructor. Options include:

secs => $seconds

time interval, in seconds. Optional; if neither secs nor deadline is specified, no timeouts will be applied.

deadline => $unix_timestamp

Unix timestamp (seconds since epoch) when a timeout is reached in the latest. Optional; if neither secs nor deadline is specified, no timeouts will be applied. If both are specified, the shorter interval of the two prevails.

$t->run($coderef)

Run a code reference within the currently-defined timeout.

The timeout is as defined by the secs and deadline parameters to the constructor.

Returns whatever the subroutine returns, or undef on timeout. If the timer times out, $t->timed_out() will return 1.

Time elapsed is not cumulative; multiple runs of run will restart the timeout from scratch. On the other hand, nested timers do observe outer timeouts if they are shorter, resignalling a timeout to the level which established them, i.e. code running under an inner timer can not exceed the time limit established by an outer timer. When restarting an outer timer on return, elapsed time of a running code is taken into account.

$t->run_and_catch($coderef)

Run a code reference, as per $t->run(), but also catching any die() calls within the code reference.

Returns undef if no die() call was executed and $@ was unset, or the value of $@ if it was set. (The timeout event doesn't count as a die().)

$t->timed_out()

Returns 1 if the most recent code executed in run() timed out, or undef if it did not.

$t->reset()

If called within a run() code reference, causes the current alarm timer to be restored to its original setting (useful after our alarm setting was clobbered by some underlying module).