LibWeb: Add skeleton for OfflineAudioContext

Implement enough to construct the object itself, with most parts stubbed
out.

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -659,6 +659,7 @@ set(SOURCES
     WebAudio/AudioBuffer.cpp
     WebAudio/AudioContext.cpp
     WebAudio/BaseAudioContext.cpp
+    WebAudio/OfflineAudioContext.cpp
     WebDriver/Capabilities.cpp
     WebDriver/Client.cpp
     WebDriver/Contexts.cpp

Userland/Libraries/LibWeb/WebAudio/OfflineAudioContext.cpp

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/HTML/Window.h>
+#include <LibWeb/WebAudio/OfflineAudioContext.h>
+
+namespace Web::WebAudio {
+
+JS_DEFINE_ALLOCATOR(OfflineAudioContext);
+
+WebIDL::ExceptionOr<JS::NonnullGCPtr<OfflineAudioContext>> OfflineAudioContext::construct_impl(JS::Realm& realm, OfflineAudioContextOptions const& context_options)
+{
+    return construct_impl(realm, context_options.number_of_channels, context_options.length, context_options.sample_rate);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-offlineaudiocontext-numberofchannels-length-samplerate
+WebIDL::ExceptionOr<JS::NonnullGCPtr<OfflineAudioContext>> OfflineAudioContext::construct_impl(JS::Realm& realm,
+    WebIDL::UnsignedLong number_of_channels, WebIDL::UnsignedLong length, float sample_rate)
+{
+    // The OfflineAudioContext can be constructed with the same arguments as AudioContext.createBuffer.
+    // A NotSupportedError exception MUST be thrown if any of the arguments is negative, zero, or outside its nominal range.
+    TRY(verify_audio_options_inside_nominal_range(realm, number_of_channels, length, sample_rate));
+
+    return realm.heap().allocate<OfflineAudioContext>(realm, realm, number_of_channels, length, sample_rate);
+}
+
+OfflineAudioContext::~OfflineAudioContext() = default;
+
+// https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-startrendering
+WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> OfflineAudioContext::start_rendering()
+{
+    return WebIDL::NotSupportedError::create(realm(), "FIXME: Implement OfflineAudioContext::start_rendering"_fly_string);
+}
+
+WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> OfflineAudioContext::resume()
+{
+    return WebIDL::NotSupportedError::create(realm(), "FIXME: Implement OfflineAudioContext::resume"_fly_string);
+}
+
+WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> OfflineAudioContext::suspend(double suspend_time)
+{
+    (void)suspend_time;
+    return WebIDL::NotSupportedError::create(realm(), "FIXME: Implement OfflineAudioContext::suspend"_fly_string);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-length
+WebIDL::UnsignedLong OfflineAudioContext::length() const
+{
+    // The size of the buffer in sample-frames. This is the same as the value of the length parameter for the constructor.
+    return m_length;
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-oncomplete
+JS::GCPtr<WebIDL::CallbackType> OfflineAudioContext::oncomplete()
+{
+    return event_handler_attribute(HTML::EventNames::complete);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-offlineaudiocontext-oncomplete
+void OfflineAudioContext::set_oncomplete(JS::GCPtr<WebIDL::CallbackType> value)
+{
+    set_event_handler_attribute(HTML::EventNames::complete, value);
+}
+
+OfflineAudioContext::OfflineAudioContext(JS::Realm& realm, OfflineAudioContextOptions const&)
+    : BaseAudioContext(realm)
+{
+}
+
+OfflineAudioContext::OfflineAudioContext(JS::Realm& realm, WebIDL::UnsignedLong number_of_channels, WebIDL::UnsignedLong length, float sample_rate)
+    : BaseAudioContext(realm)
+    , m_length(length)
+{
+    (void)number_of_channels;
+    (void)sample_rate;
+}
+
+void OfflineAudioContext::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(OfflineAudioContext);
+}
+
+void OfflineAudioContext::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+}
+
+}

Userland/Libraries/LibWeb/WebAudio/OfflineAudioContext.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/OfflineAudioContextPrototype.h>
+#include <LibWeb/HighResolutionTime/DOMHighResTimeStamp.h>
+#include <LibWeb/WebAudio/BaseAudioContext.h>
+#include <LibWeb/WebIDL/Types.h>
+
+namespace Web::WebAudio {
+
+// https://webaudio.github.io/web-audio-api/#OfflineAudioContextOptions
+struct OfflineAudioContextOptions {
+    WebIDL::UnsignedLong number_of_channels { 1 };
+    WebIDL::UnsignedLong length {};
+    float sample_rate {};
+};
+
+// https://webaudio.github.io/web-audio-api/#OfflineAudioContext
+class OfflineAudioContext final : public BaseAudioContext {
+    WEB_PLATFORM_OBJECT(OfflineAudioContext, BaseAudioContext);
+    JS_DECLARE_ALLOCATOR(OfflineAudioContext);
+
+public:
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<OfflineAudioContext>> construct_impl(JS::Realm&, OfflineAudioContextOptions const&);
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<OfflineAudioContext>> construct_impl(JS::Realm&,
+        WebIDL::UnsignedLong number_of_channels, WebIDL::UnsignedLong length, float sample_rate);
+
+    virtual ~OfflineAudioContext() override;
+
+    WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> start_rendering();
+    WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> resume();
+    WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> suspend(double suspend_time);
+
+    WebIDL::UnsignedLong length() const;
+
+    JS::GCPtr<WebIDL::CallbackType> oncomplete();
+    void set_oncomplete(JS::GCPtr<WebIDL::CallbackType>);
+
+private:
+    OfflineAudioContext(JS::Realm&, OfflineAudioContextOptions const&);
+    OfflineAudioContext(JS::Realm&, WebIDL::UnsignedLong number_of_channels, WebIDL::UnsignedLong length, float sample_rate);
+
+    virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    WebIDL::UnsignedLong m_length {};
+};
+
+}

Userland/Libraries/LibWeb/WebAudio/OfflineAudioContext.idl

@@ -0,0 +1,21 @@
+#import <WebAudio/BaseAudioContext.idl>
+
+// https://webaudio.github.io/web-audio-api/#OfflineAudioContextOptions
+dictionary OfflineAudioContextOptions {
+    unsigned long numberOfChannels = 1;
+    required unsigned long length;
+    required float sampleRate;
+    // FIXME: (AudioContextRenderSizeCategory or unsigned long) renderSizeHint = "default";
+};
+
+// https://webaudio.github.io/web-audio-api/#OfflineAudioContext
+[Exposed=Window]
+interface OfflineAudioContext : BaseAudioContext {
+    constructor(OfflineAudioContextOptions contextOptions);
+    constructor(unsigned long numberOfChannels, unsigned long length, float sampleRate);
+    Promise<AudioBuffer> startRendering();
+    Promise<undefined> resume();
+    Promise<undefined> suspend(double suspendTime);
+    readonly attribute unsigned long length;
+    attribute EventHandler oncomplete;
+};

Userland/Libraries/LibWeb/idl_files.cmake

@@ -296,6 +296,7 @@ libweb_js_bindings(WebAssembly/WebAssembly NAMESPACE)
 libweb_js_bindings(WebAudio/AudioBuffer)
 libweb_js_bindings(WebAudio/AudioContext)
 libweb_js_bindings(WebAudio/BaseAudioContext)
+libweb_js_bindings(WebAudio/OfflineAudioContext)
 libweb_js_bindings(WebGL/WebGLContextEvent)
 libweb_js_bindings(WebGL/WebGLRenderingContext)
 libweb_js_bindings(WebIDL/DOMException)