NAME

Coro::Storable - offer a more fine-grained Storable interface

SYNOPSIS

 use Coro::Storable;

DESCRIPTION

This module implements a few functions from the Storable module in a way so that it cede's more often. Some applications (such as the Deliantra game server) sometimes need to load large Storable objects without blocking the server for a long time.

This is being implemented by using a perlio layer that feeds only small amounts of data (512 bytes per call) into Storable, and Coro::cede'ing regularly (at most 100 times per second by default, though).

As it seems that Storable is not reentrant, this module also wraps most functions of the Storable module so that only one freeze or thaw is done at any one moment (recursive invocations are not currently supported).

FUNCTIONS

$ref = thaw $pst

Retrieve an object from the given $pst, which must have been created with Coro::Storable::freeze or Storable::store_fd/Storable::store (sorry, but Storable uses incompatible formats for disk/mem objects).

This works by calling Coro::cede for every 4096 bytes read in.

$pst = freeze $ref

Freeze the given scalar into a Storable object. It uses the same format as Storable::store_fd.

This works by calling Coro::cede for every write that Storable issues. Unfortunately, Storable often makes many very small writes, so it is rather inefficient. But it does keep the latency low.

$pst = nfreeze $ref

Same as freeze but is compatible to Storable::nstore_fd (note the n).

$pst = blocking_freeze $ref

Same as freeze but is guaranteed to block. This is useful e.g. in Coro::Util::fork_eval when you want to serialise a data structure for use with the thaw function for this module. You cannot use Storable::freeze for this as Storable uses incompatible formats for memory and file images.

$pst = blocking_nfreeze $ref

Same as blocking_freeze but uses nfreeze internally.

$guard = guard

Acquire the Storable lock, for when you want to call Storable yourself.

Note that this module already wraps the Storable functions, so there is rarely the need to do this yourself.

AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/