1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
/* 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::cmp::min;

use dom_struct::dom_struct;
use js::rust::{CustomAutoRooterGuard, HandleObject};
use js::typedarray::{Float32, Float32Array};
use servo_media::audio::buffer_source_node::AudioBuffer as ServoMediaAudioBuffer;

use super::bindings::buffer_source::HeapBufferSource;
use crate::dom::audionode::MAX_CHANNEL_COUNT;
use crate::dom::bindings::cell::{DomRefCell, Ref};
use crate::dom::bindings::codegen::Bindings::AudioBufferBinding::{
    AudioBufferMethods, AudioBufferOptions,
};
use crate::dom::bindings::error::{Error, Fallible};
use crate::dom::bindings::num::Finite;
use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, Reflector};
use crate::dom::bindings::root::DomRoot;
use crate::dom::globalscope::GlobalScope;
use crate::dom::window::Window;
use crate::realms::enter_realm;
use crate::script_runtime::JSContext;

// Spec mandates at least [8000, 96000], we use [8000, 192000] to match Firefox
// https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-createbuffer
pub const MIN_SAMPLE_RATE: f32 = 8000.;
pub const MAX_SAMPLE_RATE: f32 = 192000.;

/// The AudioBuffer keeps its data either in js_channels
/// or in shared_channels if js_channels buffers are detached.
///
/// js_channels buffers are (re)attached right before calling GetChannelData
/// and remain attached until its contents are needed by some other API
/// implementation. Follow <https://webaudio.github.io/web-audio-api/#acquire-the-content>
/// to know in which situations js_channels buffers must be detached.
///
#[dom_struct]
pub struct AudioBuffer {
    reflector_: Reflector,
    /// Float32Arrays returned by calls to GetChannelData.
    #[ignore_malloc_size_of = "mozjs"]
    js_channels: DomRefCell<Vec<HeapBufferSource<Float32>>>,
    /// Aggregates the data from js_channels.
    /// This is `Some<T>` iff the buffers in js_channels are detached.
    #[ignore_malloc_size_of = "servo_media"]
    #[no_trace]
    shared_channels: DomRefCell<Option<ServoMediaAudioBuffer>>,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-samplerate>
    sample_rate: f32,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-length>
    length: u32,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-duration>
    duration: f64,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiobuffer-numberofchannels>
    number_of_channels: u32,
}

impl AudioBuffer {
    #[allow(crown::unrooted_must_root)]
    pub fn new_inherited(number_of_channels: u32, length: u32, sample_rate: f32) -> AudioBuffer {
        let vec = (0..number_of_channels)
            .map(|_| HeapBufferSource::default())
            .collect();
        AudioBuffer {
            reflector_: Reflector::new(),
            js_channels: DomRefCell::new(vec),
            shared_channels: DomRefCell::new(None),
            sample_rate,
            length,
            duration: length as f64 / sample_rate as f64,
            number_of_channels,
        }
    }

    pub fn new(
        global: &Window,
        number_of_channels: u32,
        length: u32,
        sample_rate: f32,
        initial_data: Option<&[Vec<f32>]>,
    ) -> DomRoot<AudioBuffer> {
        Self::new_with_proto(
            global,
            None,
            number_of_channels,
            length,
            sample_rate,
            initial_data,
        )
    }

    #[allow(crown::unrooted_must_root)]
    fn new_with_proto(
        global: &Window,
        proto: Option<HandleObject>,
        number_of_channels: u32,
        length: u32,
        sample_rate: f32,
        initial_data: Option<&[Vec<f32>]>,
    ) -> DomRoot<AudioBuffer> {
        let buffer = AudioBuffer::new_inherited(number_of_channels, length, sample_rate);
        let buffer = reflect_dom_object_with_proto(Box::new(buffer), global, proto);
        buffer.set_initial_data(initial_data);
        buffer
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-audiobuffer
    #[allow(non_snake_case)]
    pub fn Constructor(
        window: &Window,
        proto: Option<HandleObject>,
        options: &AudioBufferOptions,
    ) -> Fallible<DomRoot<AudioBuffer>> {
        if options.length == 0 ||
            options.numberOfChannels == 0 ||
            options.numberOfChannels > MAX_CHANNEL_COUNT ||
            *options.sampleRate < MIN_SAMPLE_RATE ||
            *options.sampleRate > MAX_SAMPLE_RATE
        {
            return Err(Error::NotSupported);
        }
        Ok(AudioBuffer::new_with_proto(
            window,
            proto,
            options.numberOfChannels,
            options.length,
            *options.sampleRate,
            None,
        ))
    }

    // Initialize the underlying channels data with initial data provided by
    // the user or silence otherwise.
    fn set_initial_data(&self, initial_data: Option<&[Vec<f32>]>) {
        let mut channels = ServoMediaAudioBuffer::new(
            self.number_of_channels as u8,
            self.length as usize,
            self.sample_rate,
        );
        for channel in 0..self.number_of_channels {
            channels.buffers[channel as usize] = match initial_data {
                Some(data) => data[channel as usize].clone(),
                None => vec![0.; self.length as usize],
            };
        }
        *self.shared_channels.borrow_mut() = Some(channels);
    }

    fn restore_js_channel_data(&self, cx: JSContext) -> bool {
        let _ac = enter_realm(self);
        for (i, channel) in self.js_channels.borrow_mut().iter().enumerate() {
            if channel.is_initialized() {
                // Already have data in JS array.
                continue;
            }

            if let Some(ref shared_channels) = *self.shared_channels.borrow() {
                // Step 4. of
                // https://webaudio.github.io/web-audio-api/#acquire-the-content
                // "Attach ArrayBuffers containing copies of the data to the AudioBuffer,
                // to be returned by the next call to getChannelData()".
                if channel.set_data(cx, &shared_channels.buffers[i]).is_err() {
                    return false;
                }
            }
        }

        *self.shared_channels.borrow_mut() = None;

        true
    }

    // https://webaudio.github.io/web-audio-api/#acquire-the-content
    fn acquire_contents(&self) -> Option<ServoMediaAudioBuffer> {
        let mut result = ServoMediaAudioBuffer::new(
            self.number_of_channels as u8,
            self.length as usize,
            self.sample_rate,
        );
        let cx = GlobalScope::get_cx();
        for (i, channel) in self.js_channels.borrow_mut().iter().enumerate() {
            // Step 1.
            if !channel.is_initialized() {
                return None;
            }

            // Step 3.
            result.buffers[i] = channel.acquire_data(cx).ok()?;
        }

        Some(result)
    }

    pub fn get_channels(&self) -> Ref<Option<ServoMediaAudioBuffer>> {
        if self.shared_channels.borrow().is_none() {
            let channels = self.acquire_contents();
            if channels.is_some() {
                *self.shared_channels.borrow_mut() = channels;
            }
        }
        return self.shared_channels.borrow();
    }
}

impl AudioBufferMethods for AudioBuffer {
    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-samplerate
    fn SampleRate(&self) -> Finite<f32> {
        Finite::wrap(self.sample_rate)
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-length
    fn Length(&self) -> u32 {
        self.length
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-duration
    fn Duration(&self) -> Finite<f64> {
        Finite::wrap(self.duration)
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-numberofchannels
    fn NumberOfChannels(&self) -> u32 {
        self.number_of_channels
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-getchanneldata
    fn GetChannelData(&self, cx: JSContext, channel: u32) -> Fallible<Float32Array> {
        if channel >= self.number_of_channels {
            return Err(Error::IndexSize);
        }

        if !self.restore_js_channel_data(cx) {
            return Err(Error::JSFailed);
        }

        self.js_channels.borrow()[channel as usize]
            .get_buffer()
            .map_err(|_| Error::JSFailed)
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copyfromchannel
    #[allow(unsafe_code)]
    fn CopyFromChannel(
        &self,
        mut destination: CustomAutoRooterGuard<Float32Array>,
        channel_number: u32,
        start_in_channel: u32,
    ) -> Fallible<()> {
        if destination.is_shared() {
            return Err(Error::Type("Cannot copy to shared buffer".to_owned()));
        }

        if channel_number >= self.number_of_channels || start_in_channel >= self.length {
            return Err(Error::IndexSize);
        }

        let bytes_to_copy = min(self.length - start_in_channel, destination.len() as u32) as usize;
        let cx = GlobalScope::get_cx();
        let channel_number = channel_number as usize;
        let offset = start_in_channel as usize;
        let mut dest = vec![0.0_f32; bytes_to_copy];

        // We either copy form js_channels or shared_channels.
        let js_channel = &self.js_channels.borrow()[channel_number];
        if js_channel.is_initialized() {
            if js_channel
                .copy_data_to(cx, &mut dest, offset, offset + bytes_to_copy)
                .is_err()
            {
                return Err(Error::IndexSize);
            }
        } else if let Some(ref shared_channels) = *self.shared_channels.borrow() {
            if let Some(shared_channel) = shared_channels.buffers.get(channel_number) {
                dest.extend_from_slice(&shared_channel.as_slice()[offset..offset + bytes_to_copy]);
            }
        }

        unsafe {
            destination.update(&dest);
        }

        Ok(())
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiobuffer-copytochannel
    fn CopyToChannel(
        &self,
        source: CustomAutoRooterGuard<Float32Array>,
        channel_number: u32,
        start_in_channel: u32,
    ) -> Fallible<()> {
        if source.is_shared() {
            return Err(Error::Type("Cannot copy from shared buffer".to_owned()));
        }

        if channel_number >= self.number_of_channels || start_in_channel > (source.len() as u32) {
            return Err(Error::IndexSize);
        }

        let cx = GlobalScope::get_cx();
        if !self.restore_js_channel_data(cx) {
            return Err(Error::JSFailed);
        }

        let js_channel = &self.js_channels.borrow()[channel_number as usize];
        if !js_channel.is_initialized() {
            // The array buffer was detached.
            return Err(Error::IndexSize);
        }

        let bytes_to_copy = min(self.length - start_in_channel, source.len() as u32) as usize;
        js_channel
            .copy_data_from(cx, source, start_in_channel as usize, bytes_to_copy)
            .map_err(|_| Error::IndexSize)
    }
}