LibWeb: Add BaseAudioContext::createScriptProcessor()

This is a deprecated node, but it's still widely used on the web.

Libraries/LibWeb/WebAudio/ScriptProcessorNode.cpp

@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2025, Jelle Raaijmakers <jelle@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "BaseAudioContext.h"
+
+#include <AK/GenericShorthands.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/Bindings/ScriptProcessorNodePrototype.h>
+#include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/WebAudio/ScriptProcessorNode.h>
+
+namespace Web::WebAudio {
+
+GC_DEFINE_ALLOCATOR(ScriptProcessorNode);
+
+ScriptProcessorNode::ScriptProcessorNode(JS::Realm& realm, GC::Ref<BaseAudioContext> context,
+    u8 number_of_input_channels, u8 number_of_output_channels)
+    : AudioNode(realm, context)
+    , m_number_of_input_channels(number_of_input_channels)
+    , m_number_of_output_channels(number_of_output_channels)
+{
+}
+
+ScriptProcessorNode::~ScriptProcessorNode() = default;
+
+WebIDL::ExceptionOr<GC::Ref<ScriptProcessorNode>> ScriptProcessorNode::create(JS::Realm& realm,
+    GC::Ref<BaseAudioContext> context, WebIDL::Long buffer_size, WebIDL::UnsignedLong number_of_input_channels,
+    WebIDL::UnsignedLong number_of_output_channels)
+{
+    // https://webaudio.github.io/web-audio-api/#ScriptProcessorNode
+    // It is invalid for both numberOfInputChannels and numberOfOutputChannels to be zero. In this case an
+    // IndexSizeError MUST be thrown.
+    if (number_of_input_channels == 0 && number_of_output_channels == 0) {
+        return WebIDL::IndexSizeError::create(realm,
+            "Number of input and output channels cannot both be zero in a ScriptProcessorNode"_string);
+    }
+
+    // This parameter determines the number of channels for this node’s input. The default value is 2. Values of up to
+    // 32 must be supported. A NotSupportedError must be thrown if the number of channels is not supported.
+    if (number_of_input_channels > BaseAudioContext::MAX_NUMBER_OF_CHANNELS)
+        return WebIDL::NotSupportedError::create(realm, "Invalid number of input channels"_string);
+
+    // This parameter determines the number of channels for this node’s output. The default value is 2. Values of up to
+    // 32 must be supported. A NotSupportedError must be thrown if the number of channels is not supported.
+    if (number_of_output_channels > BaseAudioContext::MAX_NUMBER_OF_CHANNELS)
+        return WebIDL::NotSupportedError::create(realm, "Invalid number of output channels"_string);
+
+    auto script_processor_node = realm.create<ScriptProcessorNode>(realm, context,
+        number_of_input_channels, number_of_output_channels);
+
+    TRY(script_processor_node->set_buffer_size(buffer_size));
+
+    // https://webaudio.github.io/web-audio-api/#dom-audionode-channelcountmode
+    // The channel count mode cannot be changed from "explicit" and an NotSupportedError exception MUST be thrown for
+    // any attempt to change the value.
+    TRY(script_processor_node->set_channel_count_mode(Bindings::ChannelCountMode::Explicit));
+
+    return script_processor_node;
+}
+
+void ScriptProcessorNode::initialize(JS::Realm& realm)
+{
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(ScriptProcessorNode);
+    Base::initialize(realm);
+}
+
+// https://webaudio.github.io/web-audio-api/#ScriptProcessorNode
+WebIDL::UnsignedLong ScriptProcessorNode::channel_count() const
+{
+    // This is the number of channels specified when constructing this node.
+    return m_number_of_input_channels;
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-audionode-channelcount
+WebIDL::ExceptionOr<void> ScriptProcessorNode::set_channel_count(WebIDL::UnsignedLong)
+{
+    // ScriptProcessorNode: The channel count cannot be changed, and an NotSupportedError exception MUST be thrown for
+    // any attempt to change the value.
+    return WebIDL::InvalidStateError::create(realm(),
+        "Cannot modify channel count in a ScriptProcessorNode"_string);
+}
+
+WebIDL::ExceptionOr<void> ScriptProcessorNode::set_channel_count_mode(Bindings::ChannelCountMode channel_count_mode)
+{
+    // https://webaudio.github.io/web-audio-api/#audionode-channelcountmode-constraints
+    // ScriptProcessorNode: The channel count mode cannot be changed from "explicit" and an NotSupportedError exception
+    // MUST be thrown for any attempt to change the value.
+    if (channel_count_mode != Bindings::ChannelCountMode::Explicit)
+        return WebIDL::InvalidStateError::create(realm(), "Channel count mode must be 'explicit'"_string);
+
+    return AudioNode::set_channel_count_mode(channel_count_mode);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-scriptprocessornode-onaudioprocess
+GC::Ptr<WebIDL::CallbackType> ScriptProcessorNode::onaudioprocess()
+{
+    return event_handler_attribute(HTML::EventNames::audioprocess);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-scriptprocessornode-onaudioprocess
+void ScriptProcessorNode::set_onaudioprocess(GC::Ptr<WebIDL::CallbackType> value)
+{
+    set_event_handler_attribute(HTML::EventNames::audioprocess, value);
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-scriptprocessornode-buffersize
+WebIDL::ExceptionOr<void> ScriptProcessorNode::set_buffer_size(WebIDL::Long buffer_size)
+{
+    // The size of the buffer (in sample-frames) which needs to be processed each time audioprocess is fired. Legal
+    // values are (256, 512, 1024, 2048, 4096, 8192, 16384).
+
+    // https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-createscriptprocessor
+    // If the value of this parameter is not one of the allowed power-of-2 values listed above, an IndexSizeError MUST
+    // be thrown.
+    if (!first_is_one_of(buffer_size, 256, 512, 1024, 2048, 4096, 8192, 16384))
+        return WebIDL::IndexSizeError::create(realm(), "Unsupported buffer size for a ScriptProcessorNode"_string);
+
+    m_buffer_size = buffer_size;
+    return {};
+}
+
+}