WatchCallback with already freed WatchStruct

[GoogleCodeExporter]

What steps will reproduce the problem?
1. load code DLL
2. fw = new FileWatcher
3. fw->addWatch("SameDir")
4. delete fw
5. unload code DLL
6. load code DLL
7. fw = new FileWatcher
8. fw->addWatch("SameDir")

What is the expected output? What do you see instead?

when the second code dll is loaded the OS executes a WatchCallback with a
WatchStruct ( passed in lpOverlapped ) that is already destroyed. ( I have
dumped the pointers with outputdebugstring ). The dwNumberOfBytesTransfered
varies. Returning when the size is 0 is not enough, sometimes its a bigger
value. To fix the issue I have made the following modification:

bool RefreshWatch(WatchStruct* pWatch,bool _clear = false)
{
return ReadDirectoryChangesW(pWatch->mDirHandle, pWatch->mBuffer,
sizeof(pWatch->mBuffer), FALSE, pWatch->mNotifyFilter, NULL,
&pWatch->mOverlapped, _clear ? 0 : WatchCallback) != 0;
}

This allows me to clear the callback ( _clear ? 0 : WatchCallback ). The
deactivation of the callback is done in DestroyWatch:

CancelIo(pWatch->mDirHandle);

--> RefreshWatch(pWatch,true);

if (!HasOverlappedIoCompleted(&pWatch->mOverlapped))

I also return immediately when dwNumberOfBytesTransfered is 0 in the
WatchCallback

void CALLBACK WatchCallback(DWORD dwErrorCode, DWORD
dwNumberOfBytesTransfered, LPOVERLAPPED lpOverlapped)
    {
        if (dwNumberOfBytesTransfered == 0)
            return;

What version of the product are you using? On what operating system?

2009.05.14. Vista Ultimate 64Bit

Please provide any additional information below.

Original issue reported on code.google.com by Markus.O...@gmail.com on 2 Sep 2009 at 3:33

[GoogleCodeExporter]

Original comment by saintonfire on 14 Sep 2009 at 4:28

• Changed state: Accepted

[GoogleCodeExporter]

Thanks for this Fix!

Original comment by saintonfire on 15 Sep 2009 at 2:53

• Changed state: Fixed