NAME
UniEvent::FsPoll - periodicall poll for changes in a file metadata
SYNOPSIS
use UniEvent::Fs; # import constants
my $loop = UniEvent::Loop->default_loop;
my $h = UniEvent::FsPoll->new($loop);
my $file = '/path/to/file';
$h->start($file, 5.5); # check every 5.5 seconds
$h->poll_callback(sub { # periodical check
my ($handle, $prev, $curr, $error_code) = @_;
say "The contents of $file has been modified"
if (!$error_code && $curr->[STAT_MTIME] != $prev->[STAT_MTIME]);
}));
$h->start_callback(sub {
my ($handle, $init, $error_code) = @_;
# do something on the initial call with $init file stats
});
$l->run;DESCRIPTION
This handle is used to periodically poll filesystem for the specified file metadata (i.e. change time, file size etc.) and invoke the user-specified callback with the current and previous metadata (file stats).
The UniEvent::FsPoll is inherited from UniEvent::Handle.
METHODS
new([$loop = UniEvent::Loop->default_loop])
Constructs new FsPoll handle and binds it to the specified event loop.
start($path [, $interval = 1.0 [, $callback]])
Stars monitoring the specified $path for changes. Each filesystem poll would occur every $interval second(s).
The optional start $callback can be set to invoke it upon the first invocation of the handle.
stop()
Stops monitoring.
poll_event()
event()
Returns XS::Framework::CallbackDispatcher instance, where callback(s) can be assigned with. The callback will be invoked upon timer event. The C++ interface is:
void(const FsPollSP&, const opt<Fs::FStat>& prev, const opt<Fs::FStat>& cur, const std::error_code&);i.e. the callback returns nothing and as an argument takes FsPoll handle itself, optionally previous and current file stats and the error code.
Multiple callbacks can be added via the XS::Framework::CallbackDispatcher interface.
poll_callback($code)
callback($code)
Sets the callback, which will be invoked periodically on timer. All previously set event listeners or callbacks will be discarded. For the interface see event function.
start_event()
Returns XS::Framework::CallbackDispatcher instance, where callback(s) can be assigned with. The callback will be invoked once on handle start. The C++ interface is:
void(const FsPollSP&, const opt<Fs::FStat>& stat, const std::error_code&);i.e. the callback returns nothing and as an argument takes FsPoll handle itself, optionally the current file stats and the error code.
Multiple callbacks can be added via the XS::Framework::CallbackDispatcher interface.
start_callback($code)
Sets the callback $code, which will be invoked once upon handle start. All previously set event listeners or callbacks will be discarded. For the interface see start_event function.
event_listener($delegate [, $weak = false])
Delegates callback invocation to the $delegate object of arbitrary class having on_fs_start and on_fs_poll methods. The object can optionally be weakened.
The method will be invoked as
$obj->on_fs_start($init, $error_code);
$obj->on_fs_poll($prev, $curr, $error_code);path()
Returns the currently monitored path.