OfflineAudioContext

Cargo.lock

@@ -1309,6 +1309,35 @@ dependencies = [
  "pkg-config 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "gstreamer-player"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gobject-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-player-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-video 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "gstreamer-player-sys"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "glib-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gobject-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-video-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pkg-config 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "gstreamer-sys"
 version = "0.5.0"
@@ -1321,6 +1350,37 @@ dependencies = [
  "pkg-config 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "gstreamer-video"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gobject-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-base 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-base-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-video-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "gstreamer-video-sys"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gobject-sys 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-base-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pkg-config 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "gvr-sys"
 version = "0.7.0"
@@ -3076,38 +3136,48 @@ dependencies = [
 [[package]]
 name = "servo-media"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#9968654a5602adfcdc01d6a9ba9d54fd8b341eaf"
+source = "git+https://github.com/servo/media#dadf87f24830712b75e1d909bad7500f9dae952c"
 dependencies = [
  "servo-media-audio 0.1.0 (git+https://github.com/servo/media)",
  "servo-media-gstreamer 0.1.0 (git+https://github.com/servo/media)",
+ "servo-media-player 0.1.0 (git+https://github.com/servo/media)",
 ]
 
 [[package]]
 name = "servo-media-audio"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#9968654a5602adfcdc01d6a9ba9d54fd8b341eaf"
+source = "git+https://github.com/servo/media#dadf87f24830712b75e1d909bad7500f9dae952c"
 dependencies = [
  "byte-slice-cast 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "petgraph 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo_media_derive 0.1.0 (git+https://github.com/servo/media)",
- "smallvec 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "servo-media-gstreamer"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#9968654a5602adfcdc01d6a9ba9d54fd8b341eaf"
+source = "git+https://github.com/servo/media#dadf87f24830712b75e1d909bad7500f9dae952c"
 dependencies = [
  "byte-slice-cast 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glib 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gstreamer 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "gstreamer-app 0.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "gstreamer-audio 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gstreamer-player 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo-media-audio 0.1.0 (git+https://github.com/servo/media)",
+ "servo-media-player 0.1.0 (git+https://github.com/servo/media)",
  "zip 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "servo-media-player"
+version = "0.1.0"
+source = "git+https://github.com/servo/media#dadf87f24830712b75e1d909bad7500f9dae952c"
+
 [[package]]
 name = "servo-skia"
 version = "0.30000017.0"
@@ -3203,7 +3273,7 @@ dependencies = [
 [[package]]
 name = "servo_media_derive"
 version = "0.1.0"
-source = "git+https://github.com/servo/media#9968654a5602adfcdc01d6a9ba9d54fd8b341eaf"
+source = "git+https://github.com/servo/media#dadf87f24830712b75e1d909bad7500f9dae952c"
 dependencies = [
  "quote 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4213,7 +4283,11 @@ dependencies = [
 "checksum gstreamer-audio-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fd60631f2dd055f0aae2831e86bd6c1d45e24528d4c478002cc07490dd84b56e"
 "checksum gstreamer-base 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "05ec7a84b4160b61c72ea27ccf3f46eb9c8f996c5991746623e69e3e532e3cb5"
 "checksum gstreamer-base-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "501a7add44f256aab6cb5b65ef121c449197cf55087d6a7586846c8d1e42e88b"
+"checksum gstreamer-player 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "63e81d78e9e7ee5d448ba50c52722005bbbf1bfe606767c4c407f45e8996f050"
+"checksum gstreamer-player-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3b9476078cc76164446e88b2c4331e81e24a07f7b7c3a8b4bf8975a47998ebd4"
 "checksum gstreamer-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7b2f51e25a6f97dd4bfd640cba96f192f8759b8766afd66d6d9ea0f82ca14a37"
+"checksum gstreamer-video 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "75300cf1ed8d8d65811349fc755fac22be05ea55df551ab29e43664d4a575c92"
+"checksum gstreamer-video-sys 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3ed798787e78a0f1c8be06bd3adcab03f962f049a820743aae9f690f56a0d538"
 "checksum gvr-sys 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b1334b94d8ce67319ddc44663daef53d8c1538629a11562530c981dbd9085b9a"
 "checksum half 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "63d68db75012a85555434ee079e7e6337931f87a087ab2988becbadf64673a7f"
 "checksum harfbuzz-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bad27f59fc853bb88eca58088d469cd365ff0ccf362d24c4b1c0cbb1b21b3489"
@@ -4356,6 +4430,7 @@ dependencies = [
 "checksum servo-media 0.1.0 (git+https://github.com/servo/media)" = "<none>"
 "checksum servo-media-audio 0.1.0 (git+https://github.com/servo/media)" = "<none>"
 "checksum servo-media-gstreamer 0.1.0 (git+https://github.com/servo/media)" = "<none>"
+"checksum servo-media-player 0.1.0 (git+https://github.com/servo/media)" = "<none>"
 "checksum servo-skia 0.30000017.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fe33a2592a74f2096daf70bcbee39f2d183efcdc81f536a28af3a357baa6f5b0"
 "checksum servo-websocket 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6bac1e2295e72f0525147d993c626761811acf0441dac1cee8707f12dc7f3363"
 "checksum servo_media_derive 0.1.0 (git+https://github.com/servo/media)" = "<none>"

components/atoms/static_atoms.txt

@@ -12,6 +12,7 @@ checkbox
 click
 close
 color
+complete
 controllerchange
 cursive
 date

components/script/dom/audiobuffer.rs

@@ -19,6 +19,11 @@ use std::cmp::min;
 use std::mem;
 use std::ptr::{self, NonNull};
 
+// This range is defined by the spec.
+// https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-createbuffer
+pub const MIN_SAMPLE_RATE: f32 = 8000.;
+pub const MAX_SAMPLE_RATE: f32 = 96000.;
+
 type JSAudioChannel = Heap<*mut JSObject>;
 
 #[dom_struct]
@@ -112,7 +117,9 @@ impl AudioBuffer {
         window: &Window,
         options: &AudioBufferOptions,
     ) -> Fallible<DomRoot<AudioBuffer>> {
-        if options.numberOfChannels > MAX_CHANNEL_COUNT {
+        if options.numberOfChannels > MAX_CHANNEL_COUNT ||
+           *options.sampleRate < MIN_SAMPLE_RATE ||
+           *options.sampleRate > MAX_SAMPLE_RATE {
             return Err(Error::NotSupported);
         }
         Ok(AudioBuffer::new(

components/script/dom/audiocontext.rs

@@ -14,7 +14,6 @@ use dom::bindings::num::Finite;
 use dom::bindings::refcounted::{Trusted, TrustedPromise};
 use dom::bindings::reflector::{DomObject, reflect_dom_object};
 use dom::bindings::root::DomRoot;
-use dom::globalscope::GlobalScope;
 use dom::promise::Promise;
 use dom::window::Window;
 use dom_struct::dom_struct;
@@ -35,10 +34,9 @@ pub struct AudioContext {
 impl AudioContext {
     #[allow(unrooted_must_root)]
     // https://webaudio.github.io/web-audio-api/#AudioContext-constructors
-    fn new_inherited(global: &GlobalScope, options: &AudioContextOptions) -> AudioContext {
+    fn new_inherited(options: &AudioContextOptions) -> AudioContext {
         // Steps 1-3.
         let context = BaseAudioContext::new_inherited(
-            global,
             BaseAudioContextOptions::AudioContext(options.into()),
         );
 
@@ -61,9 +59,9 @@ impl AudioContext {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(global: &GlobalScope, options: &AudioContextOptions) -> DomRoot<AudioContext> {
+    pub fn new(window: &Window, options: &AudioContextOptions) -> DomRoot<AudioContext> {
-        let context = AudioContext::new_inherited(global, options);
+        let context = AudioContext::new_inherited(options);
-        let context = reflect_dom_object(Box::new(context), global, AudioContextBinding::Wrap);
+        let context = reflect_dom_object(Box::new(context), window, AudioContextBinding::Wrap);
         context.resume();
         context
     }
@@ -73,8 +71,7 @@ impl AudioContext {
         window: &Window,
         options: &AudioContextOptions,
     ) -> Fallible<DomRoot<AudioContext>> {
-        let global = window.upcast::<GlobalScope>();
+        Ok(AudioContext::new(window, options))
-        Ok(AudioContext::new(global, options))
     }
 
     fn resume(&self) {

components/script/dom/baseaudiocontext.rs

@@ -26,7 +26,6 @@ use dom::bindings::root::{DomRoot, MutNullableDom};
 use dom::domexception::{DOMErrorName, DOMException};
 use dom::eventtarget::EventTarget;
 use dom::gainnode::GainNode;
-use dom::globalscope::GlobalScope;
 use dom::oscillatornode::OscillatorNode;
 use dom::promise::Promise;
 use dom::window::Window;
@@ -34,7 +33,7 @@ use dom_struct::dom_struct;
 use js::rust::CustomAutoRooterGuard;
 use js::typedarray::ArrayBuffer;
 use servo_media::{Backend, ServoMedia};
-use servo_media::audio::context::{AudioContext, ProcessingState};
+use servo_media::audio::context::{AudioContext, AudioContextOptions, ProcessingState};
 use servo_media::audio::context::{OfflineAudioContextOptions, RealTimeAudioContextOptions};
 use servo_media::audio::decoder::AudioDecoderCallbacks;
 use servo_media::audio::graph::NodeId;
@@ -83,18 +82,17 @@ pub struct BaseAudioContext {
     /// throw when trying to do things on the context when the context has just
     /// been "closed()".
     state: Cell<AudioContextState>,
+    channel_count: u32,
 }
 
 impl BaseAudioContext {
     #[allow(unrooted_must_root)]
-    pub fn new_inherited(_: &GlobalScope, options: BaseAudioContextOptions) -> BaseAudioContext {
+    pub fn new_inherited(options: BaseAudioContextOptions) -> BaseAudioContext {
-        let options = match options {
+        let (sample_rate, channel_count) = match options {
-            BaseAudioContextOptions::AudioContext(options) => options,
+            BaseAudioContextOptions::AudioContext(ref opt) => (opt.sample_rate, 2),
-            BaseAudioContextOptions::OfflineAudioContext(_) => unimplemented!(),
+            BaseAudioContextOptions::OfflineAudioContext(ref opt) => (opt.sample_rate, opt.channels),
         };
 
-        let sample_rate = options.sample_rate;
-
         let context = BaseAudioContext {
             eventtarget: EventTarget::new_inherited(),
             audio_context_impl: Rc::new(
@@ -108,6 +106,7 @@ impl BaseAudioContext {
             decode_resolvers: Default::default(),
             sample_rate,
             state: Cell::new(AudioContextState::Suspended),
+            channel_count: channel_count.into(),
         };
 
         context
@@ -206,19 +205,19 @@ impl BaseAudioContext {
                 self.take_pending_resume_promises(Ok(()));
                 let _ = task_source.queue(
                     task!(resume_success: move || {
-                    let this = this.root();
+                        let this = this.root();
-                    this.fulfill_in_flight_resume_promises(|| {
+                        this.fulfill_in_flight_resume_promises(|| {
-                        if this.state.get() != AudioContextState::Running {
+                            if this.state.get() != AudioContextState::Running {
-                            this.state.set(AudioContextState::Running);
+                                this.state.set(AudioContextState::Running);
-                            let window = DomRoot::downcast::<Window>(this.global()).unwrap();
+                                let window = DomRoot::downcast::<Window>(this.global()).unwrap();
-                            window.dom_manipulation_task_source().queue_simple_event(
+                                window.dom_manipulation_task_source().queue_simple_event(
-                                this.upcast(),
+                                    this.upcast(),
-                                atom!("statechange"),
+                                    atom!("statechange"),
-                                &window
+                                    &window
-                                );
+                                    );
-                        }
+                            }
-                    });
+                        });
-                }),
+                    }),
                     window.upcast(),
                 );
             },
@@ -291,7 +290,7 @@ impl BaseAudioContextMethods for BaseAudioContext {
         let global = self.global();
         self.destination.or_init(|| {
             let mut options = AudioNodeOptions::empty();
-            options.channelCount = Some(2);
+            options.channelCount = Some(self.channel_count);
             options.channelCountMode = Some(ChannelCountMode::Explicit);
             options.channelInterpretation = Some(ChannelInterpretation::Speakers);
             AudioDestinationNode::new(&global, self, &options)
@@ -442,6 +441,17 @@ impl BaseAudioContextMethods for BaseAudioContext {
     }
 }
 
+impl From<BaseAudioContextOptions> for AudioContextOptions {
+    fn from(options: BaseAudioContextOptions) -> Self {
+        match options {
+            BaseAudioContextOptions::AudioContext(options) =>
+                AudioContextOptions::RealTimeAudioContext(options),
+            BaseAudioContextOptions::OfflineAudioContext(options) =>
+                AudioContextOptions::OfflineAudioContext(options),
+        }
+    }
+}
+
 impl From<ProcessingState> for AudioContextState {
     fn from(state: ProcessingState) -> Self {
         match state {

components/script/dom/mod.rs

@@ -401,6 +401,8 @@ pub mod navigatorinfo;
 pub mod node;
 pub mod nodeiterator;
 pub mod nodelist;
+pub mod offlineaudiocompletionevent;
+pub mod offlineaudiocontext;
 pub mod oscillatornode;
 pub mod pagetransitionevent;
 pub mod paintrenderingcontext2d;

components/script/dom/offlineaudiocompletionevent.rs

@@ -0,0 +1,77 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+use dom::audiobuffer::AudioBuffer;
+use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
+use dom::bindings::codegen::Bindings::OfflineAudioCompletionEventBinding;
+use dom::bindings::codegen::Bindings::OfflineAudioCompletionEventBinding::OfflineAudioCompletionEventInit;
+use dom::bindings::codegen::Bindings::OfflineAudioCompletionEventBinding::OfflineAudioCompletionEventMethods;
+use dom::bindings::error::Fallible;
+use dom::bindings::inheritance::Castable;
+use dom::bindings::reflector::reflect_dom_object;
+use dom::bindings::root::{Dom, DomRoot, RootedReference};
+use dom::bindings::str::DOMString;
+use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::window::Window;
+use dom_struct::dom_struct;
+use servo_atoms::Atom;
+
+#[dom_struct]
+pub struct OfflineAudioCompletionEvent {
+    event: Event,
+    rendered_buffer: Dom<AudioBuffer>,
+}
+
+impl OfflineAudioCompletionEvent {
+    pub fn new_inherited(rendered_buffer: &AudioBuffer) -> OfflineAudioCompletionEvent {
+        OfflineAudioCompletionEvent {
+            event: Event::new_inherited(),
+            rendered_buffer: Dom::from_ref(rendered_buffer),
+        }
+    }
+
+    pub fn new(
+        window: &Window,
+        type_: Atom,
+        bubbles: EventBubbles,
+        cancelable: EventCancelable,
+        rendered_buffer: &AudioBuffer,
+    ) -> DomRoot<OfflineAudioCompletionEvent> {
+        let event = Box::new(OfflineAudioCompletionEvent::new_inherited(rendered_buffer));
+        let ev = reflect_dom_object(event, window, OfflineAudioCompletionEventBinding::Wrap);
+        {
+            let event = ev.upcast::<Event>();
+            event.init_event(type_, bool::from(bubbles), bool::from(cancelable));
+        }
+        ev
+    }
+
+    pub fn Constructor(
+        window: &Window,
+        type_: DOMString,
+        init: &OfflineAudioCompletionEventInit,
+    ) -> Fallible<DomRoot<OfflineAudioCompletionEvent>> {
+        let bubbles = EventBubbles::from(init.parent.bubbles);
+        let cancelable = EventCancelable::from(init.parent.cancelable);
+        Ok(OfflineAudioCompletionEvent::new(
+            window,
+            Atom::from(type_),
+            bubbles,
+            cancelable,
+            init.renderedBuffer.r(),
+        ))
+    }
+}
+
+impl OfflineAudioCompletionEventMethods for OfflineAudioCompletionEvent {
+    // https://webaudio.github.io/web-audio-api/#dom-offlineaudiocompletionevent-renderedbuffer
+    fn RenderedBuffer(&self) -> DomRoot<AudioBuffer> {
+        DomRoot::from_ref(&*self.rendered_buffer)
+    }
+
+    // https://dom.spec.whatwg.org/#dom-event-istrusted
+    fn IsTrusted(&self) -> bool {
+        self.event.IsTrusted()
+    }
+}

components/script/dom/offlineaudiocontext.rs

@@ -0,0 +1,178 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+use dom::audiobuffer::{AudioBuffer, MAX_SAMPLE_RATE, MIN_SAMPLE_RATE};
+use dom::audionode::MAX_CHANNEL_COUNT;
+use dom::baseaudiocontext::{BaseAudioContext, BaseAudioContextOptions};
+use dom::bindings::cell::DomRefCell;
+use dom::bindings::codegen::Bindings::BaseAudioContextBinding::BaseAudioContextBinding::BaseAudioContextMethods;
+use dom::bindings::codegen::Bindings::OfflineAudioContextBinding;
+use dom::bindings::codegen::Bindings::OfflineAudioContextBinding::OfflineAudioContextMethods;
+use dom::bindings::codegen::Bindings::OfflineAudioContextBinding::OfflineAudioContextOptions;
+use dom::bindings::error::{Error, Fallible};
+use dom::bindings::inheritance::Castable;
+use dom::bindings::num::Finite;
+use dom::bindings::refcounted::Trusted;
+use dom::bindings::reflector::{DomObject, reflect_dom_object};
+use dom::bindings::root::DomRoot;
+use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::offlineaudiocompletionevent::OfflineAudioCompletionEvent;
+use dom::promise::Promise;
+use dom::window::Window;
+use dom_struct::dom_struct;
+use servo_media::audio::context::OfflineAudioContextOptions as ServoMediaOfflineAudioContextOptions;
+use std::cell::Cell;
+use std::rc::Rc;
+use std::sync::{Arc, Mutex};
+use std::sync::mpsc;
+use std::thread::Builder;
+use task_source::{TaskSource, TaskSourceName};
+
+#[dom_struct]
+pub struct OfflineAudioContext {
+    context: BaseAudioContext,
+    channel_count: u32,
+    length: u32,
+    rendering_started: Cell<bool>,
+    #[ignore_malloc_size_of = "promises are hard"]
+    pending_rendering_promise: DomRefCell<Option<Rc<Promise>>>,
+}
+
+impl OfflineAudioContext {
+    #[allow(unrooted_must_root)]
+    fn new_inherited(options: &OfflineAudioContextOptions) -> OfflineAudioContext {
+        let context = BaseAudioContext::new_inherited(
+            BaseAudioContextOptions::OfflineAudioContext(options.into()),
+        );
+        OfflineAudioContext {
+            context,
+            channel_count: options.numberOfChannels,
+            length: options.length,
+            rendering_started: Cell::new(false),
+            pending_rendering_promise: Default::default(),
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    fn new(window: &Window, options: &OfflineAudioContextOptions) -> DomRoot<OfflineAudioContext> {
+        let context = OfflineAudioContext::new_inherited(options);
+        reflect_dom_object(Box::new(context), window, OfflineAudioContextBinding::Wrap)
+    }
+
+    pub fn Constructor(
+        window: &Window,
+        options: &OfflineAudioContextOptions,
+    ) -> Fallible<DomRoot<OfflineAudioContext>> {
+        Ok(OfflineAudioContext::new(window, options))
+    }
+
+    pub fn Constructor_(
+        window: &Window,
+        number_of_channels: u32,
+        length: u32,
+        sample_rate: Finite<f32>,
+    ) -> Fallible<DomRoot<OfflineAudioContext>> {
+        if number_of_channels > MAX_CHANNEL_COUNT ||
+            number_of_channels <= 0 ||
+            length <= 0 ||
+            *sample_rate < MIN_SAMPLE_RATE ||
+            *sample_rate > MAX_SAMPLE_RATE
+        {
+            return Err(Error::NotSupported);
+        }
+
+        let mut options = OfflineAudioContextOptions::empty();
+        options.numberOfChannels = number_of_channels;
+        options.length = length;
+        options.sampleRate = sample_rate;
+        Ok(OfflineAudioContext::new(window, &options))
+    }
+}
+
+impl OfflineAudioContextMethods for OfflineAudioContext {
+    // https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-oncomplete
+    event_handler!(complete, GetOncomplete, SetOncomplete);
+
+    // https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-length
+    fn Length(&self) -> u32 {
+        self.length
+    }
+
+    // https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-startrendering
+    #[allow(unrooted_must_root)]
+    fn StartRendering(&self) -> Rc<Promise> {
+        let promise = Promise::new(&self.global());
+        if self.rendering_started.get() {
+            promise.reject_error(Error::InvalidState);
+            return promise;
+        }
+        self.rendering_started.set(true);
+
+        *self.pending_rendering_promise.borrow_mut() = Some(promise.clone());
+
+        let processed_audio = Arc::new(Mutex::new(Vec::new()));
+        let processed_audio_ = processed_audio.clone();
+        let (sender, receiver) = mpsc::channel();
+        let sender = Mutex::new(sender);
+        self.context
+            .audio_context_impl()
+            .set_eos_callback(Box::new(move |buffer| {
+                processed_audio_
+                    .lock()
+                    .unwrap()
+                    .extend_from_slice((*buffer).as_ref());
+                let _ = sender.lock().unwrap().send(());
+            }));
+
+        let this = Trusted::new(self);
+        let global = self.global();
+        let window = global.as_window();
+        let task_source = window.dom_manipulation_task_source();
+        let canceller = window.task_canceller(TaskSourceName::DOMManipulation);
+        Builder::new()
+            .name("OfflineAudioContextResolver".to_owned())
+            .spawn(move || {
+                let _ = receiver.recv();
+                let _ = task_source.queue_with_canceller(
+                    task!(resolve: move || {
+                        let this = this.root();
+                        let processed_audio = processed_audio.lock().unwrap();
+                        let buffer = AudioBuffer::new(
+                            &this.global().as_window(),
+                            this.channel_count,
+                            this.length,
+                            *this.context.SampleRate(),
+                            Some(processed_audio.as_slice()));
+                        (*this.pending_rendering_promise.borrow_mut()).take().unwrap().resolve_native(&buffer);
+                        let global = &this.global();
+                        let window = global.as_window();
+                        let event = OfflineAudioCompletionEvent::new(&window,
+                                                                     atom!("complete"),
+                                                                     EventBubbles::DoesNotBubble,
+                                                                     EventCancelable::NotCancelable,
+                                                                     &buffer);
+                        event.upcast::<Event>().fire(this.upcast());
+                    }),
+                    &canceller,
+                );
+            })
+            .unwrap();
+
+        if self.context.audio_context_impl().resume().is_err() {
+            promise.reject_error(Error::Type("Could not start offline rendering".to_owned()));
+        }
+
+        promise
+    }
+}
+
+impl<'a> From<&'a OfflineAudioContextOptions> for ServoMediaOfflineAudioContextOptions {
+    fn from(options: &OfflineAudioContextOptions) -> Self {
+        Self {
+            channels: options.numberOfChannels as u8,
+            length: options.length as usize,
+            sample_rate: *options.sampleRate,
+        }
+    }
+}

components/script/dom/webidls/OfflineAudioCompletionEvent.webidl

@@ -0,0 +1,17 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+/*
+ * For more information on this interface please see
+ * https://webaudio.github.io/web-audio-api/#offlineaudiocompletionevent
+ */
+
+dictionary OfflineAudioCompletionEventInit : EventInit {
+  required AudioBuffer renderedBuffer;
+};
+
+[Exposed=Window,
+ Constructor(DOMString type, OfflineAudioCompletionEventInit eventInitDict)]
+interface OfflineAudioCompletionEvent : Event {
+  readonly attribute AudioBuffer renderedBuffer;
+};

components/script/dom/webidls/OfflineAudioContext.webidl

@@ -0,0 +1,24 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+/*
+ * The origin of this IDL file is
+ * https://webaudio.github.io/web-audio-api/#OfflineAudioContext
+ */
+
+dictionary OfflineAudioContextOptions {
+  unsigned long numberOfChannels = 1;
+  unsigned long length = 0;
+  float sampleRate = 48000.;
+};
+
+[Exposed=Window,
+ Constructor (optional OfflineAudioContextOptions contextOptions),
+ Constructor (unsigned long numberOfChannels, unsigned long length, float sampleRate)]
+interface OfflineAudioContext : BaseAudioContext {
+  readonly attribute unsigned long length;
+  attribute EventHandler oncomplete;
+
+  Promise<AudioBuffer> startRendering();
+//  Promise<void> suspend(double suspendTime);
+};