IStream:Read with WaitForSingleObject leads to an application freeze

Question

My application uses a mixture of C++ native code and Java code.
The Java code is responsible for requesting data from a filestream and forwarding it to the C++ code, where it is written into the IStream implementation. The IStream-object is added to my Ole-Clipboard implementation.
After pasting a file, IStream:Read is called some x times until there are no more bytes to read (currently, since the data requests are rather slow). If that happens, my implementation for IStream:Read calls WaitForSingleObject(some eventhandle that was
passed during construction,INFINTE). Theoretically, the part of my code that writes data to the IStream-Object issues a SetEvent for the same eventhandle whenever new data is written to the stream.
Practically, my Application and the Windows Explorer freeze when this point in execution is reached, because the Read and Write calls are handled in the same thread.
I am not really sure why, since I call IStream:Write from a thread that has nothing to do with the IStream-Object (other than having a reference to it).
What can I do to fix my problem?

Answer 1

Thanks for your reply, yes I am using JNI to start a thread that handles my window-proc messages and where the Ole-library is initialized.
Java notifies this thread through a JNI-method of available data, the thread creates an IDataObject and puts it in the Ole-Clipboard.
The first time an IDataObject->GetData() request for the Filecontents format is made, the thread requests data from Java and starts writing it into an IStream-object (IStream:Write).
At some point (after the user decided to paste somewhere), the IStream:Read calls issued by the pasting program (probably explorer most of the time) reach a point where currently no data is available. My implementation of IStream:Read calls WaitForSingleObject()
in that case. Every subsequent call to IStream:Write fails because it would be executed on the same thread as IStream:Read and frankly I have no idea why and hoped somebody here could help me.
EDIT: As far as I understand it, this is basically what happens:
IStream* dsc_stream;
HANDLE ac_filerender;
typedef struct information {
HANDLE filerender;
IStream* dsc_stream;
} information;
DWORD __stdcall m_read(LPVOID dsp_stream) {
while(true) {
dsl_stream->Read(buffer,2,&bla);
DWORD __stdcall m_write(LPVOID dsp_info) {
while(true) {
dsl_info->dsc_stream->Write(buffer,10,NULL);
SetEvent(dsl_info->filerender);
int main() {
OleInitialize(NULL);
ac_filerender = CreateEvent(NULL, FALSE, FALSE, NULL);
m_create_my_stream(/*some stuff*/,&dsc_stream);
information damn;
damn.dsc_stream=dsc_stream;
damn.filerender=ac_filerender;
HANDLE threadWrite = CreateThread(NULL, 0, m_write, &damn, 0, NULL);
Sleep(10);
HANDLE threadRead = CreateThread(NULL,0,m_read,dsc_stream,0,NULL);/*...*/
GetCurrentThreadId() in IStream:Write/IStream:Read return the same threadid. Which means that I can't issue a wait-order in Read, when I need the thread running to use write.
I have no idea why IStream:Read and Write run on the same thread and am absolutely clueless on what I can do to fix this.