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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsHtml5StreamListener_h
#define nsHtml5StreamListener_h
#include "nsIStreamListener.h"
#include "nsIThreadRetargetableStreamListener.h"
#include "nsHtml5RefPtr.h"
#include "nsHtml5StreamParser.h"
/**
* The purpose of this class is to reconcile the problem that
* nsHtml5StreamParser is a cycle collection participant, which means that it
* can only be refcounted on the main thread, but
* nsIThreadRetargetableStreamListener can be refcounted from another thread,
* so nsHtml5StreamParser being an nsIThreadRetargetableStreamListener was
* a memory corruption problem.
*
* mDelegate is an nsHtml5RefPtr, which releases the object that it points
* to from a runnable on the main thread. DropDelegate() is only called on
* the main thread. This call will finish before the main-thread derefs the
* nsHtml5StreamListener itself, so there is no risk of another thread making
* the refcount of nsHtml5StreamListener go to zero and running the destructor
* concurrently. Other than that, the thread-safe nsISupports implementation
* takes care of the destructor not running concurrently from different
* threads, so there is no need to have a mutex around nsHtml5RefPtr to
* prevent it from double-releasing nsHtml5StreamParser.
*/
class nsHtml5StreamListener : public nsIStreamListener,
public nsIThreadRetargetableStreamListener
{
public:
explicit nsHtml5StreamListener(nsHtml5StreamParser* aDelegate);
NS_DECL_THREADSAFE_ISUPPORTS
NS_DECL_NSIREQUESTOBSERVER
NS_DECL_NSISTREAMLISTENER
NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
inline nsHtml5StreamParser* GetDelegate()
{
return mDelegate;
}
void DropDelegate();
private:
virtual ~nsHtml5StreamListener();
nsHtml5RefPtr<nsHtml5StreamParser> mDelegate;
};
#endif // nsHtml5StreamListener_h
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