Move the exception logic to the AudioNode creator

third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp

Index: third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp b/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
index b2f54cefc4b5ea1c6800d20057155562928d7221..a09f6e0232f7776aef75ddbf0fc97299c9a5df4a 100644
--- a/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/ChannelMergerNode.cpp
@@ -119,17 +119,43 @@ void ChannelMergerHandler::setChannelCountMode(const String& mode, ExceptionStat
 
 // ----------------------------------------------------------------
 
-ChannelMergerNode::ChannelMergerNode(AbstractAudioContext& context, float sampleRate, unsigned numberOfInputs)
+ChannelMergerNode::ChannelMergerNode(AbstractAudioContext& context, unsigned numberOfInputs)
     : AudioNode(context)
 {
-    setHandler(ChannelMergerHandler::create(*this, sampleRate, numberOfInputs));
+    setHandler(ChannelMergerHandler::create(*this, context.sampleRate(), numberOfInputs));
 }
 
-ChannelMergerNode* ChannelMergerNode::create(AbstractAudioContext& context, float sampleRate, unsigned numberOfInputs)
+ChannelMergerNode* ChannelMergerNode::create(AbstractAudioContext& context, ExceptionState& exceptionState)
 {
-    if (!numberOfInputs || numberOfInputs > AbstractAudioContext::maxNumberOfChannels())
+    ASSERT(isMainThread());

[hongchan, 2016/05/13 01:20:11]

DCHECK?

[Raymond Toy, 2016/05/20 23:12:00]

Done.

+
+    const unsigned ChannelMergerDefaultNumberOfInputs = 6;

[hongchan, 2016/05/13 01:20:11]

Can we add TODO here? - "Create a global config file that contains all the const
variable for WebAudio."

[Raymond Toy, 2016/05/13 15:59:51]

Having a global for a constant that is used in exactly one place seems overkill.

Can I just hardwire the 6 into the call? (With a comment that 6 is the default.)

+    return create(context, ChannelMergerDefaultNumberOfInputs, exceptionState);
+}
+
+ChannelMergerNode* ChannelMergerNode::create(AbstractAudioContext& context, unsigned numberOfInputs, ExceptionState& exceptionState)
+{
+    ASSERT(isMainThread());

[hongchan, 2016/05/13 01:20:11]

Ditto.

[Raymond Toy, 2016/05/20 23:12:00]

Done.

+
+    if (context.isContextClosed()) {
+        context.throwExceptionForClosedState(exceptionState);
         return nullptr;
-    return new ChannelMergerNode(context, sampleRate, numberOfInputs);
+    }
+
+    if (!numberOfInputs || numberOfInputs > AbstractAudioContext::maxNumberOfChannels()) {
+        exceptionState.throwDOMException(
+            IndexSizeError,
+            ExceptionMessages::indexOutsideRange<size_t>(
+                "number of inputs",
+                numberOfInputs,
+                1,
+                ExceptionMessages::InclusiveBound,
+                AbstractAudioContext::maxNumberOfChannels(),
+                ExceptionMessages::InclusiveBound));
+        return nullptr;
+    }
+
+    return new ChannelMergerNode(context, numberOfInputs);
 }
 
 } // namespace blink