script/dom/audio/
audiobuffer.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::cmp::min;
6
7use dom_struct::dom_struct;
8use js::context::JSContext;
9use js::rust::{CustomAutoRooterGuard, HandleObject};
10use js::typedarray::{Float32, Float32Array, HeapFloat32Array};
11use script_bindings::cell::{DomRefCell, Ref};
12use script_bindings::reflector::{Reflector, reflect_dom_object_with_proto_and_cx};
13use script_bindings::trace::RootedTraceableBox;
14use servo_media::audio::buffer_source_node::AudioBuffer as ServoMediaAudioBuffer;
15
16use crate::dom::audio::audionode::MAX_CHANNEL_COUNT;
17use crate::dom::bindings::buffer_source::HeapBufferSource;
18use crate::dom::bindings::codegen::Bindings::AudioBufferBinding::{
19    AudioBufferMethods, AudioBufferOptions,
20};
21use crate::dom::bindings::error::{Error, Fallible};
22use crate::dom::bindings::num::Finite;
23use crate::dom::bindings::root::DomRoot;
24use crate::dom::window::Window;
25use crate::realms::enter_auto_realm;
26
27// Spec mandates at least [8000, 96000], we use [8000, 192000] to match Firefox
28// https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-createbuffer
29pub(crate) const MIN_SAMPLE_RATE: f32 = 8000.;
30pub(crate) const MAX_SAMPLE_RATE: f32 = 192000.;
31
32/// The AudioBuffer keeps its data either in js_channels
33/// or in shared_channels if js_channels buffers are detached.
34///
35/// js_channels buffers are (re)attached right before calling GetChannelData
36/// and remain attached until its contents are needed by some other API
37/// implementation. Follow <https://webaudio.github.io/web-audio-api/#acquire-the-content>
38/// to know in which situations js_channels buffers must be detached.
39///
40#[dom_struct]
41pub(crate) struct AudioBuffer {
42    reflector_: Reflector,
43    /// Float32Arrays returned by calls to GetChannelData.
44    #[ignore_malloc_size_of = "mozjs"]
45    js_channels: DomRefCell<Vec<HeapBufferSource<Float32>>>,
46    /// Aggregates the data from js_channels.
47    /// This is `Some<T>` iff the buffers in js_channels are detached.
48    #[ignore_malloc_size_of = "servo_media"]
49    #[no_trace]
50    shared_channels: DomRefCell<Option<ServoMediaAudioBuffer>>,
51    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-samplerate>
52    sample_rate: f32,
53    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-length>
54    length: u32,
55    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-duration>
56    duration: f64,
57    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-numberofchannels>
58    number_of_channels: u32,
59}
60
61impl AudioBuffer {
62    #[cfg_attr(crown, expect(crown::unrooted_must_root))]
63    pub(crate) fn new_inherited(
64        number_of_channels: u32,
65        length: u32,
66        sample_rate: f32,
67    ) -> AudioBuffer {
68        let vec = (0..number_of_channels)
69            .map(|_| HeapBufferSource::default())
70            .collect();
71        AudioBuffer {
72            reflector_: Reflector::new(),
73            js_channels: DomRefCell::new(vec),
74            shared_channels: DomRefCell::new(None),
75            sample_rate,
76            length,
77            duration: length as f64 / sample_rate as f64,
78            number_of_channels,
79        }
80    }
81
82    pub(crate) fn new(
83        cx: &mut JSContext,
84        global: &Window,
85        number_of_channels: u32,
86        length: u32,
87        sample_rate: f32,
88        initial_data: Option<&[Vec<f32>]>,
89    ) -> DomRoot<AudioBuffer> {
90        Self::new_with_proto(
91            cx,
92            global,
93            None,
94            number_of_channels,
95            length,
96            sample_rate,
97            initial_data,
98        )
99    }
100
101    #[cfg_attr(crown, expect(crown::unrooted_must_root))]
102    fn new_with_proto(
103        cx: &mut JSContext,
104        global: &Window,
105        proto: Option<HandleObject>,
106        number_of_channels: u32,
107        length: u32,
108        sample_rate: f32,
109        initial_data: Option<&[Vec<f32>]>,
110    ) -> DomRoot<AudioBuffer> {
111        let buffer = AudioBuffer::new_inherited(number_of_channels, length, sample_rate);
112        let buffer = reflect_dom_object_with_proto_and_cx(Box::new(buffer), global, proto, cx);
113        buffer.set_initial_data(initial_data);
114        buffer
115    }
116
117    // Initialize the underlying channels data with initial data provided by
118    // the user or silence otherwise.
119    fn set_initial_data(&self, initial_data: Option<&[Vec<f32>]>) {
120        let mut channels = ServoMediaAudioBuffer::new(
121            self.number_of_channels as u8,
122            self.length as usize,
123            self.sample_rate,
124        );
125        for channel in 0..self.number_of_channels {
126            channels.buffers[channel as usize] = match initial_data {
127                Some(data) => data[channel as usize].clone(),
128                None => vec![0.; self.length as usize],
129            };
130        }
131        *self.shared_channels.borrow_mut() = Some(channels);
132    }
133
134    fn restore_js_channel_data(&self, cx: &mut JSContext) -> bool {
135        let mut realm = enter_auto_realm(cx, self);
136        let cx = &mut realm.current_realm();
137        for (i, channel) in self.js_channels.borrow().iter().enumerate() {
138            if channel.is_initialized() {
139                // Already have data in JS array.
140                continue;
141            }
142
143            if let Some(ref shared_channels) = *self.shared_channels.borrow() {
144                // Step 4. of
145                // https://webaudio.github.io/web-audio-api/#acquire-the-content
146                // "Attach ArrayBuffers containing copies of the data to the AudioBuffer,
147                // to be returned by the next call to getChannelData()".
148                if channel.set_data(cx, &shared_channels.buffers[i]).is_err() {
149                    return false;
150                }
151            }
152        }
153
154        *self.shared_channels.borrow_mut() = None;
155
156        true
157    }
158
159    /// <https://webaudio.github.io/web-audio-api/#acquire-the-content>
160    fn acquire_contents(&self, cx: &mut JSContext) -> Option<ServoMediaAudioBuffer> {
161        let mut result = ServoMediaAudioBuffer::new(
162            self.number_of_channels as u8,
163            self.length as usize,
164            self.sample_rate,
165        );
166        for (i, channel) in self.js_channels.borrow_mut().iter().enumerate() {
167            // Step 1.
168            if !channel.is_initialized() {
169                return None;
170            }
171
172            // Step 3.
173            result.buffers[i] = channel.acquire_data(cx).ok()?;
174        }
175
176        Some(result)
177    }
178
179    pub(crate) fn get_channels(
180        &self,
181        cx: &mut JSContext,
182    ) -> Ref<'_, Option<ServoMediaAudioBuffer>> {
183        if self.shared_channels.borrow().is_none() {
184            let channels = self.acquire_contents(cx);
185            if channels.is_some() {
186                *self.shared_channels.borrow_mut() = channels;
187            }
188        }
189        self.shared_channels.borrow()
190    }
191}
192
193impl AudioBufferMethods<crate::DomTypeHolder> for AudioBuffer {
194    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-audiobuffer>
195    fn Constructor(
196        cx: &mut JSContext,
197        window: &Window,
198        proto: Option<HandleObject>,
199        options: &AudioBufferOptions,
200    ) -> Fallible<DomRoot<AudioBuffer>> {
201        if options.length == 0 ||
202            options.numberOfChannels == 0 ||
203            options.numberOfChannels > MAX_CHANNEL_COUNT ||
204            *options.sampleRate < MIN_SAMPLE_RATE ||
205            *options.sampleRate > MAX_SAMPLE_RATE
206        {
207            return Err(Error::NotSupported(None));
208        }
209        Ok(AudioBuffer::new_with_proto(
210            cx,
211            window,
212            proto,
213            options.numberOfChannels,
214            options.length,
215            *options.sampleRate,
216            None,
217        ))
218    }
219
220    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-samplerate>
221    fn SampleRate(&self) -> Finite<f32> {
222        Finite::wrap(self.sample_rate)
223    }
224
225    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-length>
226    fn Length(&self) -> u32 {
227        self.length
228    }
229
230    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-duration>
231    fn Duration(&self) -> Finite<f64> {
232        Finite::wrap(self.duration)
233    }
234
235    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-numberofchannels>
236    fn NumberOfChannels(&self) -> u32 {
237        self.number_of_channels
238    }
239
240    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-getchanneldata>
241    fn GetChannelData(
242        &self,
243        cx: &mut JSContext,
244        channel: u32,
245    ) -> Fallible<RootedTraceableBox<HeapFloat32Array>> {
246        if channel >= self.number_of_channels {
247            return Err(Error::IndexSize(None));
248        }
249
250        if !self.restore_js_channel_data(cx) {
251            return Err(Error::JSFailed);
252        }
253
254        self.js_channels.borrow()[channel as usize]
255            .get_typed_array()
256            .map_err(|_| Error::JSFailed)
257    }
258
259    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copyfromchannel
260    fn CopyFromChannel(
261        &self,
262        cx: &mut JSContext,
263        mut destination: CustomAutoRooterGuard<Float32Array>,
264        channel_number: u32,
265        start_in_channel: u32,
266    ) -> Fallible<()> {
267        if destination.is_shared() {
268            return Err(Error::Type(c"Cannot copy to shared buffer".to_owned()));
269        }
270
271        if channel_number >= self.number_of_channels || start_in_channel >= self.length {
272            return Err(Error::IndexSize(None));
273        }
274
275        let bytes_to_copy = min(self.length - start_in_channel, destination.len() as u32) as usize;
276        let channel_number = channel_number as usize;
277        let offset = start_in_channel as usize;
278        let mut dest = vec![0.0_f32; bytes_to_copy];
279
280        // We either copy form js_channels or shared_channels.
281        let js_channel = &self.js_channels.borrow()[channel_number];
282        if js_channel.is_initialized() {
283            if js_channel
284                .copy_data_to(cx, &mut dest, offset, offset + bytes_to_copy)
285                .is_err()
286            {
287                return Err(Error::IndexSize(None));
288            }
289        } else if let Some(ref shared_channels) = *self.shared_channels.borrow() &&
290            let Some(shared_channel) = shared_channels.buffers.get(channel_number)
291        {
292            dest.extend_from_slice(&shared_channel.as_slice()[offset..offset + bytes_to_copy]);
293        }
294
295        destination.update(&dest);
296
297        Ok(())
298    }
299
300    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copytochannel>
301    fn CopyToChannel(
302        &self,
303        cx: &mut JSContext,
304        source: CustomAutoRooterGuard<Float32Array>,
305        channel_number: u32,
306        start_in_channel: u32,
307    ) -> Fallible<()> {
308        if source.is_shared() {
309            return Err(Error::Type(c"Cannot copy from shared buffer".to_owned()));
310        }
311
312        if channel_number >= self.number_of_channels || start_in_channel > (source.len() as u32) {
313            return Err(Error::IndexSize(None));
314        }
315
316        if !self.restore_js_channel_data(cx) {
317            return Err(Error::JSFailed);
318        }
319
320        let js_channel = &self.js_channels.borrow()[channel_number as usize];
321        if !js_channel.is_initialized() {
322            // The array buffer was detached.
323            return Err(Error::IndexSize(None));
324        }
325
326        let bytes_to_copy = min(self.length - start_in_channel, source.len() as u32) as usize;
327        js_channel
328            .copy_data_from(cx, source, start_in_channel as usize, bytes_to_copy)
329            .map_err(|_| Error::IndexSize(None))
330    }
331}
script/dom/audio/audiobuffer.rs

script/dom/audio/
audiobuffer.rs
