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::rust::{CustomAutoRooterGuard, HandleObject};
9use js::typedarray::{Float32, Float32Array};
10use servo_media::audio::buffer_source_node::AudioBuffer as ServoMediaAudioBuffer;
11
12use crate::dom::audio::audionode::MAX_CHANNEL_COUNT;
13use crate::dom::bindings::buffer_source::HeapBufferSource;
14use crate::dom::bindings::cell::{DomRefCell, Ref};
15use crate::dom::bindings::codegen::Bindings::AudioBufferBinding::{
16    AudioBufferMethods, AudioBufferOptions,
17};
18use crate::dom::bindings::error::{Error, Fallible};
19use crate::dom::bindings::num::Finite;
20use crate::dom::bindings::reflector::{Reflector, reflect_dom_object_with_proto};
21use crate::dom::bindings::root::DomRoot;
22use crate::dom::globalscope::GlobalScope;
23use crate::dom::window::Window;
24use crate::realms::enter_realm;
25use crate::script_runtime::{CanGc, JSContext};
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, allow(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        global: &Window,
84        number_of_channels: u32,
85        length: u32,
86        sample_rate: f32,
87        initial_data: Option<&[Vec<f32>]>,
88        can_gc: CanGc,
89    ) -> DomRoot<AudioBuffer> {
90        Self::new_with_proto(
91            global,
92            None,
93            number_of_channels,
94            length,
95            sample_rate,
96            initial_data,
97            can_gc,
98        )
99    }
100
101    #[cfg_attr(crown, allow(crown::unrooted_must_root))]
102    fn new_with_proto(
103        global: &Window,
104        proto: Option<HandleObject>,
105        number_of_channels: u32,
106        length: u32,
107        sample_rate: f32,
108        initial_data: Option<&[Vec<f32>]>,
109        can_gc: CanGc,
110    ) -> DomRoot<AudioBuffer> {
111        let buffer = AudioBuffer::new_inherited(number_of_channels, length, sample_rate);
112        let buffer = reflect_dom_object_with_proto(Box::new(buffer), global, proto, can_gc);
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: JSContext, can_gc: CanGc) -> bool {
135        let _ac = enter_realm(self);
136        for (i, channel) in self.js_channels.borrow_mut().iter().enumerate() {
137            if channel.is_initialized() {
138                // Already have data in JS array.
139                continue;
140            }
141
142            if let Some(ref shared_channels) = *self.shared_channels.borrow() {
143                // Step 4. of
144                // https://webaudio.github.io/web-audio-api/#acquire-the-content
145                // "Attach ArrayBuffers containing copies of the data to the AudioBuffer,
146                // to be returned by the next call to getChannelData()".
147                if channel
148                    .set_data(cx, &shared_channels.buffers[i], can_gc)
149                    .is_err()
150                {
151                    return false;
152                }
153            }
154        }
155
156        *self.shared_channels.borrow_mut() = None;
157
158        true
159    }
160
161    // https://webaudio.github.io/web-audio-api/#acquire-the-content
162    fn acquire_contents(&self) -> Option<ServoMediaAudioBuffer> {
163        let mut result = ServoMediaAudioBuffer::new(
164            self.number_of_channels as u8,
165            self.length as usize,
166            self.sample_rate,
167        );
168        let cx = GlobalScope::get_cx();
169        for (i, channel) in self.js_channels.borrow_mut().iter().enumerate() {
170            // Step 1.
171            if !channel.is_initialized() {
172                return None;
173            }
174
175            // Step 3.
176            result.buffers[i] = channel.acquire_data(cx).ok()?;
177        }
178
179        Some(result)
180    }
181
182    pub(crate) fn get_channels(&self) -> Ref<'_, Option<ServoMediaAudioBuffer>> {
183        if self.shared_channels.borrow().is_none() {
184            let channels = self.acquire_contents();
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        window: &Window,
197        proto: Option<HandleObject>,
198        can_gc: CanGc,
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);
208        }
209        Ok(AudioBuffer::new_with_proto(
210            window,
211            proto,
212            options.numberOfChannels,
213            options.length,
214            *options.sampleRate,
215            None,
216            can_gc,
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(&self, cx: JSContext, channel: u32, can_gc: CanGc) -> Fallible<Float32Array> {
242        if channel >= self.number_of_channels {
243            return Err(Error::IndexSize);
244        }
245
246        if !self.restore_js_channel_data(cx, can_gc) {
247            return Err(Error::JSFailed);
248        }
249
250        self.js_channels.borrow()[channel as usize]
251            .get_typed_array()
252            .map_err(|_| Error::JSFailed)
253    }
254
255    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copyfromchannel
256    #[allow(unsafe_code)]
257    fn CopyFromChannel(
258        &self,
259        mut destination: CustomAutoRooterGuard<Float32Array>,
260        channel_number: u32,
261        start_in_channel: u32,
262    ) -> Fallible<()> {
263        if destination.is_shared() {
264            return Err(Error::Type("Cannot copy to shared buffer".to_owned()));
265        }
266
267        if channel_number >= self.number_of_channels || start_in_channel >= self.length {
268            return Err(Error::IndexSize);
269        }
270
271        let bytes_to_copy = min(self.length - start_in_channel, destination.len() as u32) as usize;
272        let cx = GlobalScope::get_cx();
273        let channel_number = channel_number as usize;
274        let offset = start_in_channel as usize;
275        let mut dest = vec![0.0_f32; bytes_to_copy];
276
277        // We either copy form js_channels or shared_channels.
278        let js_channel = &self.js_channels.borrow()[channel_number];
279        if js_channel.is_initialized() {
280            if js_channel
281                .copy_data_to(cx, &mut dest, offset, offset + bytes_to_copy)
282                .is_err()
283            {
284                return Err(Error::IndexSize);
285            }
286        } else if let Some(ref shared_channels) = *self.shared_channels.borrow() {
287            if let Some(shared_channel) = shared_channels.buffers.get(channel_number) {
288                dest.extend_from_slice(&shared_channel.as_slice()[offset..offset + bytes_to_copy]);
289            }
290        }
291
292        destination.update(&dest);
293
294        Ok(())
295    }
296
297    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copytochannel
298    fn CopyToChannel(
299        &self,
300        source: CustomAutoRooterGuard<Float32Array>,
301        channel_number: u32,
302        start_in_channel: u32,
303        can_gc: CanGc,
304    ) -> Fallible<()> {
305        if source.is_shared() {
306            return Err(Error::Type("Cannot copy from shared buffer".to_owned()));
307        }
308
309        if channel_number >= self.number_of_channels || start_in_channel > (source.len() as u32) {
310            return Err(Error::IndexSize);
311        }
312
313        let cx = GlobalScope::get_cx();
314        if !self.restore_js_channel_data(cx, can_gc) {
315            return Err(Error::JSFailed);
316        }
317
318        let js_channel = &self.js_channels.borrow()[channel_number as usize];
319        if !js_channel.is_initialized() {
320            // The array buffer was detached.
321            return Err(Error::IndexSize);
322        }
323
324        let bytes_to_copy = min(self.length - start_in_channel, source.len() as u32) as usize;
325        js_channel
326            .copy_data_from(cx, source, start_in_channel as usize, bytes_to_copy)
327            .map_err(|_| Error::IndexSize)
328    }
329}
script/dom/audio/audiobuffer.rs

script/dom/audio/
audiobuffer.rs
