Support for a non-realtime plugin worker method.
This extension allows plugins to have a non-realtime worker method, with thread sychronisation and communication issues handled by the host. This allows plugins to perform non-realtime actions (such as loading files) using a simple and portable API without having to worry about the complexities of multi-threading. Because the worker thread is implemented by the host, many plugins can share the same thread and communication buffers, which reduces bloat and fixed per-plugin buffer size limitations. The host has the power to implement threads in a suitable way, while plugins are simpler and thus less error-prone. This interface is designed to gracefully handle single-threaded synchronous execution, in which case the host may simply run all work immediately. This makes it possible for the same plugin code to work with sample accuracy for offline rendering, or in real-time with non-real-time work taking place in a separate thread.
The interface provided by the plugin to implement a worker. To implement this extension, the plugin must return a valid LV2_Worker_Interface from LV2_Descriptor::extension_data() when it is called with URI LV2_WORKER__Interface. The plugin data file should describe this like so: @prefix work: <http://lv2plug.in/ns/ext/worker#> . <plugin> a lv2:Plugin ; lv2:extensionData work:Interface .
A feature which provides functions for use by the plugin to implement a worker method. To support this feature, the host must pass an LV2_Feature to LV2_Descriptor::instantiate() with URI LV2_WORKER__schedule and data pointed to an instance of LV2_Worker_Schedule.