diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/include/core/SkRefCnt.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/include/core/SkRefCnt.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,292 @@
+
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkRefCnt_DEFINED
+#define SkRefCnt_DEFINED
+
+#include "SkDynamicAnnotations.h"
+#include "SkThread.h"
+#include "SkInstCnt.h"
+#include "SkTemplates.h"
+
+/** \class SkRefCntBase
+
+    SkRefCntBase is the base class for objects that may be shared by multiple
+    objects. When an existing owner wants to share a reference, it calls ref().
+    When an owner wants to release its reference, it calls unref(). When the
+    shared object's reference count goes to zero as the result of an unref()
+    call, its (virtual) destructor is called. It is an error for the
+    destructor to be called explicitly (or via the object going out of scope on
+    the stack or calling delete) if getRefCnt() > 1.
+*/
+class SK_API SkRefCntBase : public SkNoncopyable {
+public:
+    SK_DECLARE_INST_COUNT_ROOT(SkRefCntBase)
+
+    /** Default construct, initializing the reference count to 1.
+    */
+    SkRefCntBase() : fRefCnt(1) {}
+
+    /** Destruct, asserting that the reference count is 1.
+    */
+    virtual ~SkRefCntBase() {
+#ifdef SK_DEBUG
+        SkASSERT(fRefCnt == 1);
+        fRefCnt = 0;    // illegal value, to catch us if we reuse after delete
+#endif
+    }
+
+    /** Return the reference count. Use only for debugging. */
+    int32_t getRefCnt() const { return fRefCnt; }
+
+    /** May return true if the caller is the only owner.
+     *  Ensures that all previous owner's actions are complete.
+     */
+    bool unique() const {
+        // We believe we're reading fRefCnt in a safe way here, so we stifle the TSAN warning about
+        // an unproctected read.  Generally, don't read fRefCnt, and don't stifle this warning.
+        bool const unique = (1 == SK_ANNOTATE_UNPROTECTED_READ(fRefCnt));
+        if (unique) {
+            // Acquire barrier (L/SL), if not provided by load of fRefCnt.
+            // Prevents user's 'unique' code from happening before decrements.
+            //TODO: issue the barrier.
+        }
+        return unique;
+    }
+
+    /** Increment the reference count. Must be balanced by a call to unref().
+    */
+    void ref() const {
+        SkASSERT(fRefCnt > 0);
+        sk_atomic_inc(&fRefCnt);  // No barrier required.
+    }
+
+    /** Decrement the reference count. If the reference count is 1 before the
+        decrement, then delete the object. Note that if this is the case, then
+        the object needs to have been allocated via new, and not on the stack.
+    */
+    void unref() const {
+        SkASSERT(fRefCnt > 0);
+        // Release barrier (SL/S), if not provided below.
+        if (sk_atomic_dec(&fRefCnt) == 1) {
+            // Acquire barrier (L/SL), if not provided above.
+            // Prevents code in dispose from happening before the decrement.
+            sk_membar_acquire__after_atomic_dec();
+            internal_dispose();
+        }
+    }
+
+#ifdef SK_DEBUG
+    void validate() const {
+        SkASSERT(fRefCnt > 0);
+    }
+#endif
+
+protected:
+    /**
+     *  Allow subclasses to call this if they've overridden internal_dispose
+     *  so they can reset fRefCnt before the destructor is called. Should only
+     *  be called right before calling through to inherited internal_dispose()
+     *  or before calling the destructor.
+     */
+    void internal_dispose_restore_refcnt_to_1() const {
+#ifdef SK_DEBUG
+        SkASSERT(0 == fRefCnt);
+        fRefCnt = 1;
+#endif
+    }
+
+private:
+    /**
+     *  Called when the ref count goes to 0.
+     */
+    virtual void internal_dispose() const {
+        this->internal_dispose_restore_refcnt_to_1();
+        SkDELETE(this);
+    }
+
+    // The following friends are those which override internal_dispose()
+    // and conditionally call SkRefCnt::internal_dispose().
+    friend class GrTexture;
+    friend class SkWeakRefCnt;
+
+    mutable int32_t fRefCnt;
+
+    typedef SkNoncopyable INHERITED;
+};
+
+#ifdef SK_REF_CNT_MIXIN_INCLUDE
+// It is the responsibility of the following include to define the type SkRefCnt.
+// This SkRefCnt should normally derive from SkRefCntBase.
+#include SK_REF_CNT_MIXIN_INCLUDE
+#else
+class SK_API SkRefCnt : public SkRefCntBase { };
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+
+/** Helper macro to safely assign one SkRefCnt[TS]* to another, checking for
+    null in on each side of the assignment, and ensuring that ref() is called
+    before unref(), in case the two pointers point to the same object.
+ */
+#define SkRefCnt_SafeAssign(dst, src)   \
+    do {                                \
+        if (src) src->ref();            \
+        if (dst) dst->unref();          \
+        dst = src;                      \
+    } while (0)
+
+
+/** Call obj->ref() and return obj. The obj must not be NULL.
+ */
+template <typename T> static inline T* SkRef(T* obj) {
+    SkASSERT(obj);
+    obj->ref();
+    return obj;
+}
+
+/** Check if the argument is non-null, and if so, call obj->ref() and return obj.
+ */
+template <typename T> static inline T* SkSafeRef(T* obj) {
+    if (obj) {
+        obj->ref();
+    }
+    return obj;
+}
+
+/** Check if the argument is non-null, and if so, call obj->unref()
+ */
+template <typename T> static inline void SkSafeUnref(T* obj) {
+    if (obj) {
+        obj->unref();
+    }
+}
+
+template<typename T> static inline void SkSafeSetNull(T*& obj) {
+    if (NULL != obj) {
+        obj->unref();
+        obj = NULL;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+ *  Utility class that simply unref's its argument in the destructor.
+ */
+template <typename T> class SkAutoTUnref : SkNoncopyable {
+public:
+    explicit SkAutoTUnref(T* obj = NULL) : fObj(obj) {}
+    ~SkAutoTUnref() { SkSafeUnref(fObj); }
+
+    T* get() const { return fObj; }
+
+    T* reset(T* obj) {
+        SkSafeUnref(fObj);
+        fObj = obj;
+        return obj;
+    }
+
+    void swap(SkAutoTUnref* other) {
+        T* tmp = fObj;
+        fObj = other->fObj;
+        other->fObj = tmp;
+    }
+
+    /**
+     *  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;
+    }
+
+    /**
+     *  BlockRef<B> is a type which inherits from B, cannot be created,
+     *  cannot be deleted, and makes ref and unref private.
+     */
+    template<typename B> class BlockRef : public B {
+    private:
+        BlockRef();
+        ~BlockRef();
+        void ref() const;
+        void unref() const;
+    };
+
+    /** If T is const, the type returned from operator-> will also be const. */
+    typedef typename SkTConstType<BlockRef<T>, SkTIsConst<T>::value>::type BlockRefType;
+
+    /**
+     *  SkAutoTUnref assumes ownership of the ref. As a result, it is an error
+     *  for the user to ref or unref through SkAutoTUnref. Therefore
+     *  SkAutoTUnref::operator-> returns BlockRef<T>*. This prevents use of
+     *  skAutoTUnrefInstance->ref() and skAutoTUnrefInstance->unref().
+     */
+    BlockRefType *operator->() const {
+        return static_cast<BlockRefType*>(fObj);
+    }
+    operator T*() { return fObj; }
+
+private:
+    T*  fObj;
+};
+// Can't use the #define trick below to guard a bare SkAutoTUnref(...) because it's templated. :(
+
+class SkAutoUnref : public SkAutoTUnref<SkRefCnt> {
+public:
+    SkAutoUnref(SkRefCnt* obj) : SkAutoTUnref<SkRefCnt>(obj) {}
+};
+#define SkAutoUnref(...) SK_REQUIRE_LOCAL_VAR(SkAutoUnref)
+
+class SkAutoRef : SkNoncopyable {
+public:
+    SkAutoRef(SkRefCnt* obj) : fObj(obj) { SkSafeRef(obj); }
+    ~SkAutoRef() { SkSafeUnref(fObj); }
+private:
+    SkRefCnt* fObj;
+};
+#define SkAutoRef(...) SK_REQUIRE_LOCAL_VAR(SkAutoRef)
+
+/** Wrapper class for SkRefCnt pointers. This manages ref/unref of a pointer to
+    a SkRefCnt (or subclass) object.
+ */
+template <typename T> class SkRefPtr {
+public:
+    SkRefPtr() : fObj(NULL) {}
+    SkRefPtr(T* obj) : fObj(obj) { SkSafeRef(fObj); }
+    SkRefPtr(const SkRefPtr& o) : fObj(o.fObj) { SkSafeRef(fObj); }
+    ~SkRefPtr() { SkSafeUnref(fObj); }
+
+    SkRefPtr& operator=(const SkRefPtr& rp) {
+        SkRefCnt_SafeAssign(fObj, rp.fObj);
+        return *this;
+    }
+    SkRefPtr& operator=(T* obj) {
+        SkRefCnt_SafeAssign(fObj, obj);
+        return *this;
+    }
+
+    T* get() const { return fObj; }
+    T& operator*() const { return *fObj; }
+    T* operator->() const { return fObj; }
+
+    typedef T* SkRefPtr::*unspecified_bool_type;
+    operator unspecified_bool_type() const {
+        return fObj ? &SkRefPtr::fObj : NULL;
+    }
+
+private:
+    T* fObj;
+};
+
+#endif