[PATCH v2 2/2] mfplat: Return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF) when reading past the end of a file stream.

[Zebediah Figura]

On 10/8/21 3:25 AM, Nikolay Sivov wrote:
> 
> 
> On 10/8/21 7:06 AM, Zebediah Figura wrote:
>> Signed-off-by: Zebediah Figura <zfigura at codeweavers.com>
>> ---
>>   dlls/mfplat/main.c         | 15 ++++++++++++++-
>>   dlls/mfplat/tests/mfplat.c |  2 +-
>>   2 files changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/dlls/mfplat/main.c b/dlls/mfplat/main.c
>> index 7fd713261fc..fb55a8afb21 100644
>> --- a/dlls/mfplat/main.c
>> +++ b/dlls/mfplat/main.c
>> @@ -3843,7 +3843,7 @@ static HRESULT WINAPI bytestream_file_IsEndOfStream(IMFByteStream *iface, BOOL *
>>   static HRESULT WINAPI bytestream_file_Read(IMFByteStream *iface, BYTE *buffer, ULONG size, ULONG *read_len)
>>   {
>>       struct bytestream *stream = impl_from_IMFByteStream(iface);
>> -    LARGE_INTEGER position;
>> +    LARGE_INTEGER position, file_size;
>>       HRESULT hr = S_OK;
>>       BOOL ret;
>>   
>> @@ -3851,6 +3851,19 @@ static HRESULT WINAPI bytestream_file_Read(IMFByteStream *iface, BYTE *buffer, U
>>   
>>       EnterCriticalSection(&stream->cs);
>>   
>> +    if (!GetFileSizeEx(stream->hfile, &file_size))
>> +    {
>> +        LeaveCriticalSection(&stream->cs);
>> +        return HRESULT_FROM_WIN32(GetLastError());
>> +    }
>> +
>> +    if (stream->position > file_size.QuadPart)
>> +    {
>> +        LeaveCriticalSection(&stream->cs);
>> +        *read_len = 0;
>> +        return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF);
>> +    }
>> +
> 
> I think this is too explicit. Can we rely on read length that ReadFile
> returns? Doing (ret && size && !*read_len) -> EOF. Depending on how 0
> reads work, when EOF is already reached.
> 

Sorry for the late reply. Unfortunately that doesn't work. The tests 
from patch 1 show that the bytestream reader returns S_OK when reading 
at the end of the file, but ERROR_HANDLE_EOF when reading past it. 
ReadFile() however only returns ERROR_HANDLE_EOF when doing an 
overlapped read.