bass-foundry/plugins/lathe/plugin/tests/host.rs

//! Exercise the actual exported CLAP ABI without requiring a GUI or installed DAW.
use clap_sys::{
    audio_buffer::*,
    events::*,
    ext::{audio_ports::*, latency::*, state::*},
    factory::plugin_factory::*,
    host::*,
    process::*,
    stream::*,
    version::*,
};
use std::{
    ffi::{c_char, c_void, CStr},
    io::{Cursor, Read},
    ptr,
};

unsafe extern "C" fn extension(_: *const clap_host, _: *const c_char) -> *const c_void {
    ptr::null()
}
unsafe extern "C" fn request(_: *const clap_host) {}
unsafe extern "C" fn count(_: *const clap_input_events) -> u32 {
    0
}
unsafe extern "C" fn event(_: *const clap_input_events, _: u32) -> *const clap_event_header {
    ptr::null()
}
unsafe extern "C" fn push(_: *const clap_output_events, _: *const clap_event_header) -> bool {
    true
}
unsafe extern "C" fn write(stream: *const clap_ostream, buffer: *const c_void, size: u64) -> i64 {
    // SAFETY: The test owns the Vec for the entire synchronous save call.
    let bytes = unsafe { &mut *((*stream).ctx as *mut Vec<u8>) };
    bytes.extend_from_slice(unsafe {
        std::slice::from_raw_parts(buffer as *const u8, size as usize)
    });
    size as i64
}
unsafe extern "C" fn read(stream: *const clap_istream, buffer: *mut c_void, size: u64) -> i64 {
    // SAFETY: The test owns the Cursor; the wrapper supplies writable stream storage.
    let cursor = unsafe { &mut *((*stream).ctx as *mut Cursor<Vec<u8>>) };
    cursor
        .read(unsafe { std::slice::from_raw_parts_mut(buffer as *mut u8, size as usize) })
        .unwrap() as i64
}

#[test]
fn effect_ports_state_latency_and_audio_lifecycle() {
    // SAFETY: All callbacks, strings, streams, buffers, and the host outlive their
    // synchronous ABI calls. Activation/processing/destruction follow CLAP order.
    unsafe {
        let entry = &lathe::clap_entry;
        assert!(entry.init.unwrap()(c"lathe.clap".as_ptr()));
        let factory = entry.get_factory.unwrap()(CLAP_PLUGIN_FACTORY_ID.as_ptr())
            as *const clap_plugin_factory;
        assert!(!factory.is_null());
        let factory = &*factory;
        assert_eq!(factory.get_plugin_count.unwrap()(factory), 1);
        let descriptor = factory.get_plugin_descriptor.unwrap()(factory, 0);
        assert!(!descriptor.is_null());
        assert_eq!(CStr::from_ptr((*descriptor).name), c"Lathe");
        assert_eq!(
            CStr::from_ptr((*descriptor).id),
            c"io.narl.bass-foundry.lathe"
        );
        assert!(factory.get_plugin_descriptor.unwrap()(factory, 1).is_null());
        let host = clap_host {
            clap_version: CLAP_VERSION,
            host_data: ptr::null_mut(),
            name: c"Storyboard test host".as_ptr(),
            vendor: c"Tests".as_ptr(),
            url: c"".as_ptr(),
            version: c"1.0".as_ptr(),
            get_extension: Some(extension),
            request_restart: Some(request),
            request_process: Some(request),
            request_callback: Some(request),
        };
        let plugin = factory.create_plugin.unwrap()(factory, &host, (*descriptor).id);
        assert!(!plugin.is_null());
        let p = &*plugin;
        assert!(p.init.unwrap()(plugin));
        let ports = p.get_extension.unwrap()(plugin, CLAP_EXT_AUDIO_PORTS.as_ptr())
            as *const clap_plugin_audio_ports;
        assert!(!ports.is_null());
        assert_eq!((*ports).count.unwrap()(plugin, false), 1);
        assert_eq!((*ports).count.unwrap()(plugin, true), 1);
        let latency = p.get_extension.unwrap()(plugin, CLAP_EXT_LATENCY.as_ptr())
            as *const clap_plugin_latency;
        assert!(!latency.is_null());
        let state =
            p.get_extension.unwrap()(plugin, CLAP_EXT_STATE.as_ptr()) as *const clap_plugin_state;
        assert!(!state.is_null());
        let state = &*state;
        let save = || {
            let mut bytes = Vec::new();
            let stream = clap_ostream {
                ctx: &mut bytes as *mut Vec<u8> as *mut c_void,
                write: Some(write),
            };
            assert!(state.save.unwrap()(plugin, &stream));
            bytes
        };
        let mut envelope: nih_plug::prelude::PluginState =
            serde_json::from_slice(&save()[8..]).unwrap();
        use nih_plug::wrapper::state::ParamValue;
        envelope.params.insert("tilt".into(), ParamValue::F32(-3.));
        envelope
            .params
            .insert("harmonics".into(), ParamValue::I32(16));
        let mut gains = [0f32; 32];
        gains[2] = -12.;
        gains[4] = 6.;
        envelope
            .fields
            .insert("lathe-gains".into(), serde_json::to_string(&gains).unwrap());
        envelope
            .params
            .insert("snap".into(), ParamValue::Bool(false));
        envelope
            .params
            .insert("source".into(), ParamValue::String("midi".into()));
        let encoded = serde_json::to_vec(&envelope).unwrap();
        let mut framed = (encoded.len() as u64).to_le_bytes().to_vec();
        framed.extend_from_slice(&encoded);
        let mut bytes = Cursor::new(framed);
        let stream = clap_istream {
            ctx: &mut bytes as *mut Cursor<Vec<u8>> as *mut c_void,
            read: Some(read),
        };
        assert!(state.load.unwrap()(plugin, &stream));
        let restored: nih_plug::prelude::PluginState =
            serde_json::from_slice(&save()[8..]).unwrap();
        assert_eq!(
            serde_json::to_value(&restored.params).unwrap(),
            serde_json::to_value(&envelope.params).unwrap()
        );
        let saved: [f32; 32] = serde_json::from_str(&restored.fields["lathe-gains"]).unwrap();
        assert_eq!(saved, gains);
        for rate in [44100., 48000., 96000.] {
            assert!(p.activate.unwrap()(plugin, rate, 1, 512));
            let delay = (*latency).get.unwrap()(plugin) as usize;
            // About 67 ms lookahead: two periods of the lowest detected note (30 Hz).
            assert!((delay as f64 / rate - 0.067).abs() < 0.01, "{delay}");
            assert!(p.start_processing.unwrap()(plugin));
            let total = delay + 9600;
            let mut position = 0;
            let (mut energy_in, mut energy_out) = (0f64, 0f64);
            while position < total {
                let frames = [1, 127, 512, 31][position % 4].min(total - position);
                // A 1 kHz tone sits above the split and passes through unchanged.
                let tone = |n: usize| {
                    0.25 * (std::f64::consts::TAU * 1000. * n as f64 / rate).sin() as f32
                };
                let mut input_left = [0f32; 512];
                let mut input_right = [0f32; 512];
                for i in 0..frames {
                    input_left[i] = tone(position + i);
                    input_right[i] = -tone(position + i);
                }
                let mut left = [0f32; 512];
                let mut right = [0f32; 512];
                let mut in_channels = [input_left.as_mut_ptr(), input_right.as_mut_ptr()];
                let mut out_channels = [left.as_mut_ptr(), right.as_mut_ptr()];
                let incoming = clap_audio_buffer {
                    data32: in_channels.as_mut_ptr(),
                    data64: ptr::null_mut(),
                    channel_count: 2,
                    latency: 0,
                    constant_mask: 0,
                };
                let mut outgoing_audio = clap_audio_buffer {
                    data32: out_channels.as_mut_ptr(),
                    data64: ptr::null_mut(),
                    channel_count: 2,
                    latency: 0,
                    constant_mask: 0,
                };
                let input = clap_input_events {
                    ctx: ptr::null_mut(),
                    size: Some(count),
                    get: Some(event),
                };
                let outgoing = clap_output_events {
                    ctx: ptr::null_mut(),
                    try_push: Some(push),
                };
                let process = clap_process {
                    steady_time: position as i64,
                    frames_count: frames as u32,
                    transport: ptr::null(),
                    audio_inputs: &incoming,
                    audio_outputs: &mut outgoing_audio,
                    audio_inputs_count: 1,
                    audio_outputs_count: 1,
                    in_events: &input,
                    out_events: &outgoing,
                };
                assert_ne!(p.process.unwrap()(plugin, &process), CLAP_PROCESS_ERROR);
                for i in 0..frames {
                    let n = position + i;
                    if n < delay {
                        assert!(left[i].abs() < 1e-6, "output before the lookahead");
                    } else if n > delay + 4800 {
                        energy_in += (tone(n - delay) as f64).powi(2);
                        energy_out += (left[i] as f64).powi(2) + (right[i] as f64).powi(2);
                    }
                }
                position += frames;
            }
            let ratio_db = 10. * (energy_out / (2. * energy_in)).log10();
            assert!(ratio_db.abs() < 0.2, "{ratio_db}");
            p.stop_processing.unwrap()(plugin);
            p.deactivate.unwrap()(plugin);
        }
        p.destroy.unwrap()(plugin);
        entry.deinit.unwrap()();
    }
}