servo/components/script/dom/gainnode.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

use std::f32;

use dom_struct::dom_struct;
use js::rust::HandleObject;
use servo_media::audio::gain_node::GainNodeOptions;
use servo_media::audio::node::{AudioNodeInit, AudioNodeType};
use servo_media::audio::param::ParamType;

use crate::conversions::Convert;
use crate::dom::audionode::{AudioNode, AudioNodeOptionsHelper};
use crate::dom::audioparam::AudioParam;
use crate::dom::baseaudiocontext::BaseAudioContext;
use crate::dom::bindings::codegen::Bindings::AudioNodeBinding::{
    ChannelCountMode, ChannelInterpretation,
};
use crate::dom::bindings::codegen::Bindings::AudioParamBinding::AutomationRate;
use crate::dom::bindings::codegen::Bindings::GainNodeBinding::{GainNodeMethods, GainOptions};
use crate::dom::bindings::error::Fallible;
use crate::dom::bindings::reflector::reflect_dom_object_with_proto;
use crate::dom::bindings::root::{Dom, DomRoot};
use crate::dom::window::Window;
use crate::script_runtime::CanGc;

#[dom_struct]
pub(crate) struct GainNode {
    node: AudioNode,
    gain: Dom<AudioParam>,
}

impl GainNode {
    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
    pub(crate) fn new_inherited(
        window: &Window,
        context: &BaseAudioContext,
        options: &GainOptions,
        can_gc: CanGc,
    ) -> Fallible<GainNode> {
        let node_options =
            options
                .parent
                .unwrap_or(2, ChannelCountMode::Max, ChannelInterpretation::Speakers);
        let gain = *options.gain;
        let node = AudioNode::new_inherited(
            AudioNodeInit::GainNode(options.convert()),
            context,
            node_options,
            1, // inputs
            1, // outputs
        )?;
        let gain = AudioParam::new(
            window,
            context,
            node.node_id(),
            AudioNodeType::GainNode,
            ParamType::Gain,
            AutomationRate::A_rate,
            gain,     // default value
            f32::MIN, // min value
            f32::MAX, // max value
            can_gc,
        );
        Ok(GainNode {
            node,
            gain: Dom::from_ref(&gain),
        })
    }

    pub(crate) fn new(
        window: &Window,
        context: &BaseAudioContext,
        options: &GainOptions,
        can_gc: CanGc,
    ) -> Fallible<DomRoot<GainNode>> {
        Self::new_with_proto(window, None, context, options, can_gc)
    }

    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
    fn new_with_proto(
        window: &Window,
        proto: Option<HandleObject>,
        context: &BaseAudioContext,
        options: &GainOptions,
        can_gc: CanGc,
    ) -> Fallible<DomRoot<GainNode>> {
        let node = GainNode::new_inherited(window, context, options, can_gc)?;
        Ok(reflect_dom_object_with_proto(
            Box::new(node),
            window,
            proto,
            can_gc,
        ))
    }
}

impl GainNodeMethods<crate::DomTypeHolder> for GainNode {
    // https://webaudio.github.io/web-audio-api/#dom-gainnode-gainnode
    fn Constructor(
        window: &Window,
        proto: Option<HandleObject>,
        can_gc: CanGc,
        context: &BaseAudioContext,
        options: &GainOptions,
    ) -> Fallible<DomRoot<GainNode>> {
        GainNode::new_with_proto(window, proto, context, options, can_gc)
    }

    // https://webaudio.github.io/web-audio-api/#dom-gainnode-gain
    fn Gain(&self) -> DomRoot<AudioParam> {
        DomRoot::from_ref(&self.gain)
    }
}

impl Convert<GainNodeOptions> for GainOptions {
    fn convert(self) -> GainNodeOptions {
        GainNodeOptions { gain: *self.gain }
    }
}