Wrap SkStreams in IStreams instead of copying data around.
http://codereview.appspot.com/4630062/


git-svn-id: http://skia.googlecode.com/svn/trunk@1694 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/utils/win/SkTScopedComPtr.h b/include/utils/win/SkTScopedComPtr.h
new file mode 100644
index 0000000..202dc7e
--- /dev/null
+++ b/include/utils/win/SkTScopedComPtr.h
@@ -0,0 +1,47 @@
+/*
+    Copyright 2011 Google Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+#ifndef SkSkTScopedPtr_DEFINED
+#define SkSkTScopedPtr_DEFINED
+
+#include "SkTemplates.h"
+
+template<typename T>
+class SkTScopedComPtr : SkNoncopyable {
+private:
+    T *fPtr;
+
+public:
+    explicit SkTScopedComPtr(T *ptr = NULL) : fPtr(ptr) { }
+    ~SkTScopedComPtr() {
+        if (NULL != fPtr) {
+            fPtr->Release();
+            fPtr = NULL;
+        }
+    }
+    T &operator*() const { return *fPtr; }
+    T *operator->() const { return fPtr; }
+    /**
+     * Returns the address of the underlying pointer.
+     * This is dangerous -- it breaks encapsulation and the reference escapes.
+     * Must only be used on instances currently pointing to NULL,
+     * and only to initialize the instance.
+     */
+    T **operator&() { SkASSERT(fPtr == NULL); return &fPtr; }
+    T *get() const { return fPtr; }
+};
+
+#endif