ole32: Use real blocking operations for storage locking when possible.

dlls/ole32/filelockbytes.c

@@ -356,6 +356,25 @@ static HRESULT WINAPI FileLockBytesImpl_LockRegion(ILockBytes* iface,
         return STG_E_ACCESSDENIED;
 }
 
+HRESULT FileLockBytesImpl_LockRegionSync(ILockBytes* iface,
+    ULARGE_INTEGER libOffset, ULARGE_INTEGER cb)
+{
+    FileLockBytesImpl* This = impl_from_ILockBytes(iface);
+    OVERLAPPED ol;
+
+    if (iface->lpVtbl != &FileLockBytesImpl_Vtbl)
+        return E_NOTIMPL;
+
+    ol.hEvent = 0;
+    ol.u.s.Offset = libOffset.u.LowPart;
+    ol.u.s.OffsetHigh = libOffset.u.HighPart;
+
+    if (LockFileEx(This->hfile, LOCKFILE_EXCLUSIVE_LOCK, 0, cb.u.LowPart, cb.u.HighPart, &ol))
+        return S_OK;
+    else
+        return STG_E_ACCESSDENIED;
+}
+
 static HRESULT WINAPI FileLockBytesImpl_UnlockRegion(ILockBytes* iface,
     ULARGE_INTEGER libOffset, ULARGE_INTEGER cb, DWORD dwLockType)
 {

dlls/ole32/storage32.c

@@ -2831,8 +2831,11 @@ static HRESULT StorageImpl_LockRegionSync(StorageImpl *This, ULARGE_INTEGER offs
 {
     HRESULT hr;
 
-    /* potential optimization: if we have an HFILE use LockFileEx in blocking mode directly */
+    /* if it's a FileLockBytesImpl use LockFileEx in blocking mode */
+    if (SUCCEEDED(FileLockBytesImpl_LockRegionSync(This->lockBytes, offset, cb)))
+        return S_OK;
 
+    /* otherwise we have to fake it based on an async lock */
     do
     {
         int delay=0;

dlls/ole32/storage32.h

@@ -157,6 +157,8 @@ struct DirEntry
 
 HRESULT FileLockBytesImpl_Construct(HANDLE hFile, DWORD openFlags, LPCWSTR pwcsName, ILockBytes **pLockBytes) DECLSPEC_HIDDEN;
 
+HRESULT FileLockBytesImpl_LockRegionSync(ILockBytes* iface, ULARGE_INTEGER libOffset, ULARGE_INTEGER cb) DECLSPEC_HIDDEN;
+
 /*************************************************************************
  * Ole Convert support
  */