Move the exception logic to the AudioNode creator

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

 /*
  * Copyright (C) 2010 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
@@ skipping 101 matching lines @@
     // channcelCountMode must be 'explicit'.
     if (mode != "explicit") {
         exceptionState.throwDOMException(
             InvalidStateError,
             "ChannelMerger: channelCountMode cannot be changed from 'explicit'");
     }
 }
 
 // ----------------------------------------------------------------
 
-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