| Index: include/private/SkWeakRefCnt.h
|
| diff --git a/include/private/SkWeakRefCnt.h b/include/private/SkWeakRefCnt.h
|
| deleted file mode 100644
|
| index a550951970c925eb93d86bb6aa9869c52fa054ca..0000000000000000000000000000000000000000
|
| --- a/include/private/SkWeakRefCnt.h
|
| +++ /dev/null
|
| @@ -1,159 +0,0 @@
|
| -/*
|
| - * Copyright 2012 Google Inc.
|
| - *
|
| - * Use of this source code is governed by a BSD-style license that can be
|
| - * found in the LICENSE file.
|
| - */
|
| -
|
| -#ifndef SkWeakRefCnt_DEFINED
|
| -#define SkWeakRefCnt_DEFINED
|
| -
|
| -#include "SkRefCnt.h"
|
| -#include "SkAtomics.h"
|
| -
|
| -/** \class SkWeakRefCnt
|
| -
|
| - SkWeakRefCnt is the base class for objects that may be shared by multiple
|
| - objects. When an existing strong owner wants to share a reference, it calls
|
| - ref(). When a strong owner wants to release its reference, it calls
|
| - unref(). When the shared object's strong reference count goes to zero as
|
| - the result of an unref() call, its (virtual) weak_dispose method 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.
|
| -
|
| - In addition to strong ownership, an owner may instead obtain a weak
|
| - reference by calling weak_ref(). A call to weak_ref() must be balanced by a
|
| - call to weak_unref(). To obtain a strong reference from a weak reference,
|
| - call try_ref(). If try_ref() returns true, the owner's pointer is now also
|
| - a strong reference on which unref() must be called. Note that this does not
|
| - affect the original weak reference, weak_unref() must still be called. When
|
| - the weak reference count goes to zero, the object is deleted. While the
|
| - weak reference count is positive and the strong reference count is zero the
|
| - object still exists, but will be in the disposed state. It is up to the
|
| - object to define what this means.
|
| -
|
| - Note that a strong reference implicitly implies a weak reference. As a
|
| - result, it is allowable for the owner of a strong ref to call try_ref().
|
| - This will have the same effect as calling ref(), but may be more expensive.
|
| -
|
| - Example:
|
| -
|
| - SkWeakRefCnt myRef = strongRef.weak_ref();
|
| - ... // strongRef.unref() may or may not be called
|
| - if (myRef.try_ref()) {
|
| - ... // use myRef
|
| - myRef.unref();
|
| - } else {
|
| - // myRef is in the disposed state
|
| - }
|
| - myRef.weak_unref();
|
| -*/
|
| -class SK_API SkWeakRefCnt : public SkRefCnt {
|
| -public:
|
| - /** Default construct, initializing the reference counts to 1.
|
| - The strong references collectively hold one weak reference. When the
|
| - strong reference count goes to zero, the collectively held weak
|
| - reference is released.
|
| - */
|
| - SkWeakRefCnt() : SkRefCnt(), fWeakCnt(1) {}
|
| -
|
| - /** Destruct, asserting that the weak reference count is 1.
|
| - */
|
| - virtual ~SkWeakRefCnt() {
|
| -#ifdef SK_DEBUG
|
| - SkASSERT(fWeakCnt == 1);
|
| - fWeakCnt = 0;
|
| -#endif
|
| - }
|
| -
|
| - /** Return the weak reference count.
|
| - */
|
| - int32_t getWeakCnt() const { return fWeakCnt; }
|
| -
|
| -#ifdef SK_DEBUG
|
| - void validate() const {
|
| - this->INHERITED::validate();
|
| - SkASSERT(fWeakCnt > 0);
|
| - }
|
| -#endif
|
| -
|
| - /** Creates a strong reference from a weak reference, if possible. The
|
| - caller must already be an owner. If try_ref() returns true the owner
|
| - is in posession of an additional strong reference. Both the original
|
| - reference and new reference must be properly unreferenced. If try_ref()
|
| - returns false, no strong reference could be created and the owner's
|
| - reference is in the same state as before the call.
|
| - */
|
| - bool SK_WARN_UNUSED_RESULT try_ref() const {
|
| - if (sk_atomic_conditional_inc(&fRefCnt) != 0) {
|
| - // Acquire barrier (L/SL), if not provided above.
|
| - // Prevents subsequent code from happening before the increment.
|
| - sk_membar_acquire__after_atomic_conditional_inc();
|
| - return true;
|
| - }
|
| - return false;
|
| - }
|
| -
|
| - /** Increment the weak reference count. Must be balanced by a call to
|
| - weak_unref().
|
| - */
|
| - void weak_ref() const {
|
| - SkASSERT(fRefCnt > 0);
|
| - SkASSERT(fWeakCnt > 0);
|
| - sk_atomic_inc(&fWeakCnt); // No barrier required.
|
| - }
|
| -
|
| - /** Decrement the weak reference count. If the weak reference count is 1
|
| - before the decrement, then call delete on 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 weak_unref() const {
|
| - SkASSERT(fWeakCnt > 0);
|
| - // Release barrier (SL/S), if not provided below.
|
| - if (sk_atomic_dec(&fWeakCnt) == 1) {
|
| - // Acquire barrier (L/SL), if not provided above.
|
| - // Prevents code in destructor from happening before the decrement.
|
| - sk_membar_acquire__after_atomic_dec();
|
| -#ifdef SK_DEBUG
|
| - // so our destructor won't complain
|
| - fWeakCnt = 1;
|
| -#endif
|
| - this->INHERITED::internal_dispose();
|
| - }
|
| - }
|
| -
|
| - /** Returns true if there are no strong references to the object. When this
|
| - is the case all future calls to try_ref() will return false.
|
| - */
|
| - bool weak_expired() const {
|
| - return fRefCnt == 0;
|
| - }
|
| -
|
| -protected:
|
| - /** Called when the strong reference count goes to zero. This allows the
|
| - object to free any resources it may be holding. Weak references may
|
| - still exist and their level of allowed access to the object is defined
|
| - by the object's class.
|
| - */
|
| - virtual void weak_dispose() const {
|
| - }
|
| -
|
| -private:
|
| - /** Called when the strong reference count goes to zero. Calls weak_dispose
|
| - on the object and releases the implicit weak reference held
|
| - collectively by the strong references.
|
| - */
|
| - void internal_dispose() const override {
|
| - weak_dispose();
|
| - weak_unref();
|
| - }
|
| -
|
| - /* Invariant: fWeakCnt = #weak + (fRefCnt > 0 ? 1 : 0) */
|
| - mutable int32_t fWeakCnt;
|
| -
|
| - typedef SkRefCnt INHERITED;
|
| -};
|
| -
|
| -#endif
|
|
|