Vincent Povirk : windowscodecs: Fix crash when PNG decoder is freed without successful init.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 27ae589d2aee548d06401153a2bdc5f9af98329d
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=27ae589d2aee548d06401153a2...

Author: Vincent Povirk <vincent(a)codeweavers.com>
Date:   Fri Apr 10 11:39:34 2015 -0500

windowscodecs: Fix crash when PNG decoder is freed without successful init.

---

 dlls/windowscodecs/pngformat.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/windowscodecs/pngformat.c b/dlls/windowscodecs/pngformat.c
index 2aac560..f39b31a 100644
--- a/dlls/windowscodecs/pngformat.c
+++ b/dlls/windowscodecs/pngformat.c
@@ -442,7 +442,8 @@ static ULONG WINAPI PngDecoder_Release(IWICBitmapDecoder *iface)
 
     if (ref == 0)
     {
-        IStream_Release(This->stream);
+        if (This->stream)
+            IStream_Release(This->stream);
         if (This->png_ptr)
             ppng_destroy_read_struct(&This->png_ptr, &This->info_ptr, &This->end_info);
         This->lock.DebugInfo->Spare[0] = 0;
@@ -1218,6 +1219,7 @@ HRESULT PngDecoder_CreateInstance(REFIID iid, void** ppv)
     This->png_ptr = NULL;
     This->info_ptr = NULL;
     This->end_info = NULL;
+    This->stream = NULL;
     This->initialized = FALSE;
     This->image_bits = NULL;
     InitializeCriticalSection(&This->lock);