LibWeb: Validate parameters for source node start() and stop() methods

Author: https://github.com/tcl3
Commit: 3261f873c5
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3204

Libraries/LibWeb/WebAudio/AudioScheduledSourceNode.cpp

@@ -35,14 +35,38 @@ void AudioScheduledSourceNode::set_onended(GC::Ptr<WebIDL::CallbackType> value)
 // https://webaudio.github.io/web-audio-api/#dom-audioscheduledsourcenode-start
 WebIDL::ExceptionOr<void> AudioScheduledSourceNode::start(double when)
 {
-    (void)when;
+    // 1. If this AudioScheduledSourceNode internal slot [[source started]] is true, an InvalidStateError exception MUST be thrown.
+    if (source_started())
+        return WebIDL::InvalidStateError::create(realm(), "AudioScheduledSourceNode source has already started"_string);
+
+    // 2. Check for any errors that must be thrown due to parameter constraints described below. If any exception is thrown during this step, abort those steps.
+    // A RangeError exception MUST be thrown if when is negative.
+    if (when < 0)
+        return WebIDL::SimpleException { WebIDL::SimpleExceptionType::RangeError, "when must not be negative"sv };
+
+    // 3. Set the internal slot [[source started]] on this AudioScheduledSourceNode to true.
+    set_source_started(true);
+
+    // FIXME: 4. Queue a control message to start the AudioScheduledSourceNode, including the parameter values in the message.
+    // FIXME: 5. Send a control message to the associated AudioContext to start running its rendering thread only when all the following conditions are met:
+
     return WebIDL::NotSupportedError::create(realm(), "FIXME: Implement AudioScheduledSourceNode::start"_string);
 }
 
 // https://webaudio.github.io/web-audio-api/#dom-audioscheduledsourcenode-stop
 WebIDL::ExceptionOr<void> AudioScheduledSourceNode::stop(double when)
 {
-    (void)when;
+    // 1. If this AudioScheduledSourceNode internal slot [[source started]] is not true, an InvalidStateError exception MUST be thrown.
+    if (!m_source_started)
+        return WebIDL::InvalidStateError::create(realm(), "AudioScheduledSourceNode source has not been started"_string);
+
+    // 2. Check for any errors that must be thrown due to parameter constraints described below.
+    // A RangeError exception MUST be thrown if when is negative.
+    if (when < 0)
+        return WebIDL::SimpleException { WebIDL::SimpleExceptionType::RangeError, "when must not be negative"sv };
+
+    // FIXME: 3. Queue a control message to stop the AudioScheduledSourceNode, including the parameter values in the message.
+
     return WebIDL::NotSupportedError::create(realm(), "FIXME: Implement AudioScheduledSourceNode::stop"_string);
 }