LibWeb: Add barebones BaseAudioContext.decodeAudioData()

Implement just enough steps to get https://zty.pe/ working! :^)

Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.cpp

@@ -9,6 +9,8 @@
 #include <LibWeb/Bindings/BaseAudioContextPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/HTML/Scripting/ExceptionReporter.h>
+#include <LibWeb/HTML/Window.h>
 #include <LibWeb/WebAudio/AudioBuffer.h>
 #include <LibWeb/WebAudio/AudioBufferSourceNode.h>
 #include <LibWeb/WebAudio/AudioDestinationNode.h>
@@ -17,6 +19,8 @@
 #include <LibWeb/WebAudio/DynamicsCompressorNode.h>
 #include <LibWeb/WebAudio/GainNode.h>
 #include <LibWeb/WebAudio/OscillatorNode.h>
+#include <LibWeb/WebIDL/AbstractOperations.h>
+#include <LibWeb/WebIDL/Promise.h>
 
 namespace Web::WebAudio {
 
@@ -120,4 +124,122 @@ void BaseAudioContext::queue_a_media_element_task(JS::NonnullGCPtr<JS::HeapFunct
     HTML::main_thread_event_loop().task_queue().add(task);
 }
 
+// https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-decodeaudiodata
+JS::NonnullGCPtr<JS::Promise> BaseAudioContext::decode_audio_data(JS::Handle<WebIDL::BufferSource> audio_data, JS::GCPtr<WebIDL::CallbackType> success_callback, JS::GCPtr<WebIDL::CallbackType> error_callback)
+{
+    auto& realm = this->realm();
+
+    // FIXME: When decodeAudioData is called, the following steps MUST be performed on the control thread:
+
+    // 1. If this's relevant global object's associated Document is not fully active then return a
+    //    promise rejected with "InvalidStateError" DOMException.
+    auto const& associated_document = verify_cast<HTML::Window>(HTML::relevant_global_object(*this)).associated_document();
+    if (!associated_document.is_fully_active()) {
+        auto error = WebIDL::InvalidStateError::create(realm, "The document is not fully active."_string);
+        return WebIDL::create_rejected_promise_from_exception(realm, error);
+    }
+
+    // 2. Let promise be a new Promise.
+    auto promise = WebIDL::create_promise(realm);
+
+    // FIXME: 3. If audioData is detached, execute the following steps:
+    if (true) {
+        // FIXME: 3.1. Append promise to [[pending promises]].
+
+        // FIXME: 3.2. Detach the audioData ArrayBuffer. If this operations throws, jump to the step 3.
+
+        // 3.3. Queue a decoding operation to be performed on another thread.
+        queue_a_decoding_operation(promise, move(audio_data), success_callback, error_callback);
+    }
+
+    // 4. Else, execute the following error steps:
+    else {
+        // 4.1. Let error be a DataCloneError.
+        auto error = WebIDL::DataCloneError::create(realm, "Audio data is not detached."_string);
+
+        // 4.2. Reject promise with error, and remove it from [[pending promises]].
+        WebIDL::reject_promise(realm, promise, error);
+
+        // 4.3. Queue a media element task to invoke errorCallback with error.
+        if (error_callback) {
+            queue_a_media_element_task(JS::create_heap_function(heap(), [&realm, error_callback, error] {
+                auto completion = WebIDL::invoke_callback(*error_callback, {}, error);
+                if (completion.is_abrupt())
+                    HTML::report_exception(completion, realm);
+            }));
+        }
+    }
+
+    // 5. Return promise.
+    return verify_cast<JS::Promise>(*promise->promise());
+}
+
+// https://webaudio.github.io/web-audio-api/#dom-baseaudiocontext-decodeaudiodata
+void BaseAudioContext::queue_a_decoding_operation(JS::NonnullGCPtr<JS::PromiseCapability> promise, [[maybe_unused]] JS::Handle<WebIDL::BufferSource> audio_data, JS::GCPtr<WebIDL::CallbackType> success_callback, JS::GCPtr<WebIDL::CallbackType> error_callback)
+{
+    auto& realm = this->realm();
+
+    // FIXME: When queuing a decoding operation to be performed on another thread, the following steps
+    //        MUST happen on a thread that is not the control thread nor the rendering thread, called
+    //        the decoding thread.
+
+    // 1. Let can decode be a boolean flag, initially set to true.
+    auto can_decode { true };
+
+    // FIXME: 2. Attempt to determine the MIME type of audioData, using MIME Sniffing § 6.2 Matching an
+    //           audio or video type pattern. If the audio or video type pattern matching algorithm returns
+    //           undefined, set can decode to false.
+
+    // 3. If can decode is true,
+    if (can_decode) {
+        // FIXME: attempt to decode the encoded audioData into linear PCM. In case of
+        //        failure, set can decode to false.
+
+        // FIXME: If the media byte-stream contains multiple audio tracks, only decode the first track to linear pcm.
+    }
+
+    // 4. If can decode is false,
+    if (!can_decode) {
+        // queue a media element task to execute the following steps:
+        queue_a_media_element_task(JS::create_heap_function(heap(), [&realm, promise, error_callback] {
+            // 4.1. Let error be a DOMException whose name is EncodingError.
+            auto error = WebIDL::EncodingError::create(realm, "Unable to decode."_string);
+
+            // 4.1.2. Reject promise with error,
+            WebIDL::reject_promise(realm, promise, error);
+            // FIXME: and remove it from [[pending promises]].
+
+            // 4.2. If errorCallback is not missing, invoke errorCallback with error.
+            if (error_callback) {
+                auto completion = WebIDL::invoke_callback(*error_callback, {}, error);
+                if (completion.is_abrupt())
+                    HTML::report_exception(completion, realm);
+            }
+        }));
+    }
+
+    // 5. Otherwise:
+    else {
+        // FIXME: 5.1. Take the result, representing the decoded linear PCM audio data, and resample it to the
+        //             sample-rate of the BaseAudioContext if it is different from the sample-rate of
+        //             audioData.
+
+        // FIXME: 5.2. queue a media element task to execute the following steps:
+
+        // FIXME: 5.2.1. Let buffer be an AudioBuffer containing the final result (after possibly performing
+        //               sample-rate conversion).
+        auto buffer = MUST(create_buffer(2, 1, 44100));
+
+        // 5.2.2. Resolve promise with buffer.
+        WebIDL::resolve_promise(realm, promise, buffer);
+
+        // 5.2.3. If successCallback is not missing, invoke successCallback with buffer.
+        if (success_callback) {
+            auto completion = WebIDL::invoke_callback(*success_callback, {}, buffer);
+            if (completion.is_abrupt())
+                HTML::report_exception(completion, realm);
+        }
+    }
+}
+
 }

Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.h

@@ -59,6 +59,8 @@ class BaseAudioContext : public DOM::EventTarget {
     WebIDL::ExceptionOr<JS::NonnullGCPtr<DynamicsCompressorNode>> create_dynamics_compressor();
     JS::NonnullGCPtr<GainNode> create_gain();
 
+    JS::NonnullGCPtr<JS::Promise> decode_audio_data(JS::Handle<WebIDL::BufferSource>, JS::GCPtr<WebIDL::CallbackType>, JS::GCPtr<WebIDL::CallbackType>);
+
 protected:
     explicit BaseAudioContext(JS::Realm&, float m_sample_rate = 0);
 
@@ -70,6 +72,8 @@ class BaseAudioContext : public DOM::EventTarget {
     JS::NonnullGCPtr<AudioDestinationNode> m_destination;
 
 private:
+    void queue_a_decoding_operation(JS::NonnullGCPtr<JS::PromiseCapability>, JS::Handle<WebIDL::BufferSource>, JS::GCPtr<WebIDL::CallbackType>, JS::GCPtr<WebIDL::CallbackType>);
+
     float m_sample_rate { 0 };
     double m_current_time { 0 };
 

Userland/Libraries/LibWeb/WebAudio/BaseAudioContext.idl

@@ -6,13 +6,14 @@
 #import <WebAudio/DynamicsCompressorNode.idl>
 #import <WebAudio/GainNode.idl>
 #import <WebAudio/OscillatorNode.idl>
+#import <WebIDL/DOMException.idl>
 
 // https://www.w3.org/TR/webaudio/#enumdef-audiocontextstate
 enum AudioContextState { "suspended", "running", "closed" };
 
-// FIXME: callback DecodeErrorCallback = undefined (DOMException error);
+callback DecodeErrorCallback = undefined (DOMException error);
 
-// FIXME: callback DecodeSuccessCallback = undefined (AudioBuffer decodedData);
+callback DecodeSuccessCallback = undefined (AudioBuffer decodedData);
 
 // https://webaudio.github.io/web-audio-api/#BaseAudioContext
 [Exposed=Window]
@@ -45,5 +46,5 @@ interface BaseAudioContext : EventTarget {
     [FIXME] StereoPannerNode createStereoPanner ();
     [FIXME] WaveShaperNode createWaveShaper ();
 
-    [FIXME] Promise<AudioBuffer> decodeAudioData (ArrayBuffer audioData, optional DecodeSuccessCallback? successCallback, optional DecodeErrorCallback? errorCallback);
+    Promise<AudioBuffer> decodeAudioData (ArrayBuffer audioData, optional DecodeSuccessCallback? successCallback, optional DecodeErrorCallback? errorCallback);
 };