Trait lv2_core::port::PortCollection

pub trait PortCollection: Sized {
    type Cache: PortPointerCache;
    unsafe fn from_connections(
        cache: &Self::Cache, 
        sample_count: u32
    ) -> Option<Self>;
}

Collection of IO ports.

Plugins do not handle port management on their own. Instead, they define a struct with all of the required ports. Then, the plugin instance will collect the port pointers from the host and create a PortCollection instance for every run call. Using this instance, plugins have access to all of their required ports.

Implementing

The most convenient way to create a port collections is to define a struct with port types from the port module and then simply derive PortCollection for it. An example:

use lv2_core::port::*;

#[derive(PortCollection)]
struct MyPortCollection {
    audio_input: InputPort<Audio>,
    audio_output: OutputPort<Audio>,
    control_input: InputPort<Control>,
    control_output: OutputPort<Control>,
    optional_control_input: Option<InputPort<Control>>,
}

Please note that port indices are mapped in the order of occurence; In our example, the implementation will treat audio_input as port 0, audio_output as port 1 and so on. Therefore, your plugin definition and your port collection have to match. Otherwise, undefined behaviour will occur.

Associated Types

type Cache: PortPointerCache

The type of the port pointer cache.

The host passes port pointers to the plugin one by one and in an undefined order. Therefore, the plugin instance can not collect these pointers in the port collection directly. Instead, the pointers are stored in a cache which is then used to create the proper port collection.

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Required methods

unsafe fn from_connections(
    cache: &Self::Cache,
    sample_count: u32
) -> Option<Self>

Try to construct a port collection instance from a port pointer cache.

If one of the port connection pointers is null, this method will return None, because a PortCollection can not be constructed.

Safety

Since the pointer cache is only storing the pointers, implementing this method requires the de-referencation of raw pointers and therefore, this method is unsafe.

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Implementations on Foreign Types

impl PortCollection for ()

type Cache = ()

unsafe fn from_connections(_cache: &(), _sample_count: u32) -> Option<Self>

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Implementors

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