Add QFileDevice::MemoryMapFlags::MapPrivateOption flag.

Passing this flag to QFileDevice::map() will allow writes to the mapped memory
without modifying the file that was mapped. These writes will be lost when the
memory is unmapped.

Change-Id: I7d46b044fc370585de8c06fdb4059f1f1be12d7d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/src/corelib/io/qfsfileengine_win.cpp b/src/corelib/io/qfsfileengine_win.cpp
index fb4107b95d..81aed5f7b4 100644
--- a/src/corelib/io/qfsfileengine_win.cpp
+++ b/src/corelib/io/qfsfileengine_win.cpp
@@ -965,6 +965,21 @@ uchar *QFSFileEnginePrivate::map(qint64 offset, qint64 size,
         return 0;
     }
 
+    // check/setup args to map
+    DWORD access = 0;
+    if (flags & QFileDevice::MapPrivateOption) {
+#ifdef FILE_MAP_COPY
+        access = FILE_MAP_COPY;
+#else
+        q->setError(QFile::UnspecifiedError, "MapPrivateOption unsupported");
+        return 0;
+#endif
+    } else if (openMode & QIODevice::WriteOnly) {
+        access = FILE_MAP_WRITE;
+    } else if (openMode & QIODevice::ReadOnly) {
+        access = FILE_MAP_READ;
+    }
+
     if (mapHandle == NULL) {
         // get handle to the file
         HANDLE handle = fileHandle;
@@ -1011,11 +1026,6 @@ uchar *QFSFileEnginePrivate::map(qint64 offset, qint64 size,
         }
     }
 
-    // setup args to map
-    DWORD access = 0;
-    if (openMode & QIODevice::ReadOnly) access = FILE_MAP_READ;
-    if (openMode & QIODevice::WriteOnly) access = FILE_MAP_WRITE;
-
     DWORD offsetHi = offset >> 32;
     DWORD offsetLo = offset & Q_UINT64_C(0xffffffff);
     SYSTEM_INFO sysinfo;