Signal exceptions if start/stop is called out-of-order or too many times.

Source/modules/webaudio/AudioScheduledSourceNode.cpp

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #if ENABLE(WEB_AUDIO)
 
 #include "modules/webaudio/AudioScheduledSourceNode.h"
 
+#include "bindings/v8/ExceptionMessages.h"
+#include "bindings/v8/ExceptionState.h"
+#include "core/dom/ExceptionCode.h"
 #include "core/events/Event.h"
 #include "platform/audio/AudioUtilities.h"
 #include "modules/webaudio/AudioContext.h"
 #include <algorithm>
 #include "wtf/MathExtras.h"
 
 using namespace std;
 
 namespace WebCore {
 
 const double AudioScheduledSourceNode::UnknownTime = -1;
 
 AudioScheduledSourceNode::AudioScheduledSourceNode(AudioContext* context, float sampleRate)
     : AudioSourceNode(context, sampleRate)
     , m_playbackState(UNSCHEDULED_STATE)
     , m_startTime(0)
     , m_endTime(UnknownTime)
     , m_hasEndedListener(false)
+    , m_stopCalled(false)
 {
 }
 
 void AudioScheduledSourceNode::updateSchedulingInfo(size_t quantumFrameSize,
                                                     AudioBus* outputBus,
                                                     size_t& quantumFrameOffset,
                                                     size_t& nonSilentFramesToProcess)
 {
     ASSERT(outputBus);
     if (!outputBus)
@@ skipping 68 matching lines @@
             for (unsigned i = 0; i < outputBus->numberOfChannels(); ++i)
                 memset(outputBus->channel(i)->mutableData() + zeroStartFrame, 0, sizeof(float) * framesToZero);
         }
 
         finish();
     }
 
     return;
 }
 
-void AudioScheduledSourceNode::start(double when)
+
+void AudioScheduledSourceNode::start(double when, ExceptionState& es)
 {
     ASSERT(isMainThread());
-    if (m_playbackState != UNSCHEDULED_STATE)
+
+    if (m_playbackState != UNSCHEDULED_STATE) {
+        es.throwDOMException(
+            InvalidStateError,
+            ExceptionMessages::failedToExecute(
+                "start",
+                "OscillatorNode",
+                "cannot call start more than once."));
         return;
+    }
 
     m_startTime = when;
     m_playbackState = SCHEDULED_STATE;
 }
 
-void AudioScheduledSourceNode::stop(double when)
+void AudioScheduledSourceNode::stop(double when, ExceptionState& es)
 {
     ASSERT(isMainThread());
-    if (!(m_playbackState == SCHEDULED_STATE || m_playbackState == PLAYING_STATE))
-        return;
 
-    when = max(0.0, when);
-    m_endTime = when;
-}
-
-void AudioScheduledSourceNode::noteOn(double when)
-{
-    start(when);
-}
-
-void AudioScheduledSourceNode::noteOff(double when)
-{
-    stop(when);
+    if (m_stopCalled) {
+        es.throwDOMException(
+            InvalidStateError,
+            ExceptionMessages::failedToExecute(
+                "stop",
+                "OscillatorNode",
+                "cannot call stop more than once."));
+    } else if (m_playbackState == UNSCHEDULED_STATE) {
+        es.throwDOMException(
+            InvalidStateError,
+            ExceptionMessages::failedToExecute(
+                "stop",
+                "OscillatorNode",
+                "cannot call stop without calling start first."));
+    } else {
+        // This can only happen from the SCHEDULED_STATE or PLAYING_STATE. The UNSCHEDULED_STATE is
+        // handled above, and the FINISHED_STATE is only reachable after stop() has been called, and
+        // hence m_stopCalled is true. But that case is handled above.
+        when = max(0.0, when);
+        m_endTime = when;
+        m_stopCalled = true;
+    }
 }
 
 void AudioScheduledSourceNode::setOnended(PassRefPtr<EventListener> listener, DOMWrapperWorld* isolatedWorld)
 {
     m_hasEndedListener = listener;
     setAttributeEventListener(EventTypeNames::ended, listener, isolatedWorld);
 }
 
 void AudioScheduledSourceNode::finish()
 {
@@ skipping 26 matching lines @@
 void AudioScheduledSourceNode::NotifyEndedTask::notifyEnded()
 {
     RefPtr<Event> event = Event::create(EventTypeNames::ended);
     event->setTarget(m_scheduledNode);
     m_scheduledNode->dispatchEvent(event.get());
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)