From a67573e25faa81ea65e6fc368f66d3f0c0a5f189 Mon Sep 17 00:00:00 2001
From: "reed@google.com" <reed@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81>
Date: Fri, 25 Feb 2011 18:10:29 +0000
Subject: http://codereview.appspot.com/4233041/

Add templated version of SkAutoTUnref.
Add unittests for it.
Remove unused helper apis on SkAutoUnref.



git-svn-id: http://skia.googlecode.com/svn/trunk@858 2bbb7eff-a529-9590-31e7-b0007b416f81
---
 include/core/SkRefCnt.h | 49 ++++++++++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

(limited to 'include/core')

diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index f109ead4c7..2024e08c9b 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -67,36 +67,35 @@ private:
     mutable int32_t fRefCnt;
 };
 
-/** \class SkAutoUnref
-
-    SkAutoUnref is a stack-helper class that will automatically call unref() on
-    the object it points to when the SkAutoUnref object goes out of scope.
-    If obj is null, do nothing.
-*/
-class SkAutoUnref : SkNoncopyable {
+/**
+ *  Utility class that simply unref's its argument in the destructor.
+ */
+template <typename T> class SkAutoTUnref : SkNoncopyable {
 public:
-    SkAutoUnref(SkRefCnt* obj) : fObj(obj) {}
-    ~SkAutoUnref();
-
-    SkRefCnt*   get() const { return fObj; }
+    SkAutoTUnref(T* obj) : fObj(obj) {}
+    ~SkAutoTUnref() { SkSafeUnref(fObj); }
 
-    /** If the hosted object is null, do nothing and return false, else call
-        ref() on it and return true
-    */
-    bool        ref();
-
-    /** If the hosted object is null, do nothing and return false, else call
-        unref() on it, set its reference to null, and return true
-    */
-    bool        unref();
+    T* get() const { return fObj; }
 
-    /** If the hosted object is null, do nothing and return NULL, else call
-        unref() on it, set its reference to null, and return the object
-    */
-    SkRefCnt*   detach();
+    /**
+     *  Return the hosted object (which may be null), transferring ownership.
+     *  The reference count is not modified, and the internal ptr is set to NULL
+     *  so unref() will not be called in our destructor. A subsequent call to
+     *  detach() will do nothing and return null.
+     */
+    T* detach() {
+        T* obj = fObj;
+        fObj = NULL;
+        return obj;
+    }
 
 private:
-    SkRefCnt*   fObj;
+    T*  fObj;
+};
+
+class SkAutoUnref : public SkAutoTUnref<SkRefCnt> {
+public:
+    SkAutoUnref(SkRefCnt* obj) : SkAutoTUnref<SkRefCnt>(obj) {}
 };
 
 ///////////////////////////////////////////////////////////////////////////////
-- 
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