LibWeb: Add ConstantSourceNode interface

Author: https://github.com/tcl3
Commit: https://github.com/LadybirdBrowser/ladybird/commit/1b160044c40
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3102
Reviewed-by: https://github.com/shannonbooth

Libraries/LibWeb/CMakeLists.txt

@@ -794,6 +794,7 @@ set(SOURCES
     WebAudio/BiquadFilterNode.cpp
     WebAudio/ChannelMergerNode.cpp
     WebAudio/ChannelSplitterNode.cpp
+    WebAudio/ConstantSourceNode.cpp
     WebAudio/DynamicsCompressorNode.cpp
     WebAudio/GainNode.cpp
     WebAudio/OfflineAudioContext.cpp

Libraries/LibWeb/WebAudio/ConstantSourceNode.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025, Tim Ledbetter <tim.ledbetter@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/NumericLimits.h>
+#include <LibWeb/Bindings/ConstantSourceNodePrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/WebAudio/BaseAudioContext.h>
+#include <LibWeb/WebAudio/ConstantSourceNode.h>
+
+namespace Web::WebAudio {
+
+GC_DEFINE_ALLOCATOR(ConstantSourceNode);
+
+ConstantSourceNode::ConstantSourceNode(JS::Realm& realm, GC::Ref<BaseAudioContext> context, ConstantSourceOptions const& options)
+    : AudioScheduledSourceNode(realm, context)
+    , m_offset(AudioParam::create(realm, options.offset, NumericLimits<float>::lowest(), NumericLimits<float>::max(), Bindings::AutomationRate::ARate))
+{
+}
+
+ConstantSourceNode::~ConstantSourceNode() = default;
+
+WebIDL::ExceptionOr<GC::Ref<ConstantSourceNode>> ConstantSourceNode::create(JS::Realm& realm, GC::Ref<BaseAudioContext> context, ConstantSourceOptions const& options)
+{
+    return construct_impl(realm, context, options);
+}
+
+WebIDL::ExceptionOr<GC::Ref<ConstantSourceNode>> ConstantSourceNode::construct_impl(JS::Realm& realm, GC::Ref<BaseAudioContext> context, ConstantSourceOptions const& options)
+{
+    return realm.create<ConstantSourceNode>(realm, context, options);
+}
+
+void ConstantSourceNode::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(ConstantSourceNode);
+}
+
+void ConstantSourceNode::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_offset);
+}
+
+}

Libraries/LibWeb/WebAudio/ConstantSourceNode.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2025, Tim Ledbetter <tim.ledbetter@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/WebAudio/AudioScheduledSourceNode.h>
+
+namespace Web::WebAudio {
+
+// https://webaudio.github.io/web-audio-api/#ChannelMergerOptions
+struct ConstantSourceOptions : AudioNodeOptions {
+    float offset { 1.0f };
+};
+
+// https://webaudio.github.io/web-audio-api/#ChannelMergerNode
+class ConstantSourceNode final : public AudioScheduledSourceNode {
+    WEB_PLATFORM_OBJECT(ConstantSourceNode, AudioScheduledSourceNode);
+    GC_DECLARE_ALLOCATOR(ConstantSourceNode);
+
+public:
+    virtual ~ConstantSourceNode() override;
+
+    static WebIDL::ExceptionOr<GC::Ref<ConstantSourceNode>> create(JS::Realm&, GC::Ref<BaseAudioContext>, ConstantSourceOptions const& = {});
+    static WebIDL::ExceptionOr<GC::Ref<ConstantSourceNode>> construct_impl(JS::Realm&, GC::Ref<BaseAudioContext>, ConstantSourceOptions const& = {});
+
+    virtual WebIDL::UnsignedLong number_of_inputs() override { return 0; }
+    virtual WebIDL::UnsignedLong number_of_outputs() override { return 1; }
+
+    GC::Ref<AudioParam const> offset() const { return m_offset; }
+
+private:
+    ConstantSourceNode(JS::Realm&, GC::Ref<BaseAudioContext>, ConstantSourceOptions const&);
+
+    virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    // https://webaudio.github.io/web-audio-api/#dom-constantsourcenode-offset
+    GC::Ref<AudioParam> m_offset;
+};
+
+}

Libraries/LibWeb/WebAudio/ConstantSourceNode.idl

@@ -0,0 +1,15 @@
+#import <WebAudio/AudioNode.idl>
+#import <WebAudio/AudioParam.idl>
+#import <WebAudio/BaseAudioContext.idl>
+
+// https://webaudio.github.io/web-audio-api/#ConstantSourceOptions
+dictionary ConstantSourceOptions {
+    float offset = 1;
+};
+
+// https://webaudio.github.io/web-audio-api/#ConstantSourceNode
+[Exposed=Window]
+interface ConstantSourceNode : AudioScheduledSourceNode {
+    constructor (BaseAudioContext context, optional ConstantSourceOptions options = {});
+    readonly attribute AudioParam offset;
+};

Libraries/LibWeb/idl_files.cmake

@@ -371,6 +371,7 @@ libweb_js_bindings(WebAudio/DynamicsCompressorNode)
 libweb_js_bindings(WebAudio/GainNode)
 libweb_js_bindings(WebAudio/ChannelMergerNode)
 libweb_js_bindings(WebAudio/ChannelSplitterNode)
+libweb_js_bindings(WebAudio/ConstantSourceNode)
 libweb_js_bindings(WebAudio/OfflineAudioContext)
 libweb_js_bindings(WebAudio/OscillatorNode)
 libweb_js_bindings(WebAudio/PannerNode)

Tests/LibWeb/Text/expected/all-window-properties.txt

@@ -67,6 +67,7 @@ CloseWatcher
 Comment
 CompositionEvent
 CompressionStream
+ConstantSourceNode
 CountQueuingStrategy
 Crypto
 CryptoKey

Tests/LibWeb/Text/expected/wpt-import/webaudio/the-audio-api/the-constantsourcenode-interface/ctor-constantsource.txt

@@ -0,0 +1,29 @@
+Harness status: OK
+
+Found 24 tests
+
+24 Pass
+Pass	# AUDIT TASK RUNNER STARTED.
+Pass	Executing "initialize"
+Pass	Executing "invalid constructor"
+Pass	Executing "default constructor"
+Pass	Audit report
+Pass	> [initialize] 
+Pass	  context = new OfflineAudioContext(...) did not throw an exception.
+Pass	< [initialize] All assertions passed. (total 1 assertions)
+Pass	> [invalid constructor] 
+Pass	  new ConstantSourceNode() threw TypeError: "ConstantSourceNode() needs one argument".
+Pass	  new ConstantSourceNode(1) threw TypeError: "Not an object of type BaseAudioContext".
+Pass	  new ConstantSourceNode(context, 42) threw TypeError: "Not an object of type ConstantSourceOptions".
+Pass	< [invalid constructor] All assertions passed. (total 3 assertions)
+Pass	> [default constructor] 
+Pass	  node0 = new ConstantSourceNode(context) did not throw an exception.
+Pass	  node0 instanceof ConstantSourceNode is equal to true.
+Pass	  node0.numberOfInputs is equal to 0.
+Pass	  node0.numberOfOutputs is equal to 1.
+Pass	  node0.channelCount is equal to 2.
+Pass	  node0.channelCountMode is equal to max.
+Pass	  node0.channelInterpretation is equal to speakers.
+Pass	  node0.offset.value is equal to 1.
+Pass	< [default constructor] All assertions passed. (total 8 assertions)
+Pass	# AUDIT TASK RUNNER FINISHED: 3 tasks ran successfully.

Tests/LibWeb/Text/input/wpt-import/webaudio/the-audio-api/the-constantsourcenode-interface/ctor-constantsource.html

@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>
+      Test Constructor: ConstantSource
+    </title>
+    <script src="../../../resources/testharness.js"></script>
+    <script src="../../../resources/testharnessreport.js"></script>
+    <script src="../../../webaudio/resources/audit-util.js"></script>
+    <script src="../../../webaudio/resources/audit.js"></script>
+    <script src="../../../webaudio/resources/audionodeoptions.js"></script>
+  </head>
+  <body>
+    <script id="layout-test-code">
+      let context;
+
+      let audit = Audit.createTaskRunner();
+
+      audit.define('initialize', (task, should) => {
+        context = initializeContext(should);
+        task.done();
+      });
+
+      audit.define('invalid constructor', (task, should) => {
+        testInvalidConstructor(should, 'ConstantSourceNode', context);
+        task.done();
+      });
+
+      audit.define('default constructor', (task, should) => {
+        let prefix = 'node0';
+        let node =
+            testDefaultConstructor(should, 'ConstantSourceNode', context, {
+              prefix: prefix,
+              numberOfInputs: 0,
+              numberOfOutputs: 1,
+              channelCount: 2,
+              channelCountMode: 'max',
+              channelInterpretation: 'speakers'
+            });
+
+        testDefaultAttributes(
+            should, node, prefix, [{name: 'offset', value: 1}]);
+
+        task.done();
+      });
+
+      audit.run();
+    </script>
+  </body>
+</html>