Index: webrtc/base/linked_ptr.h |
diff --git a/webrtc/base/linked_ptr.h b/webrtc/base/linked_ptr.h |
new file mode 100644 |
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+++ b/webrtc/base/linked_ptr.h |
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+/* |
+ * Copyright 2004 The WebRTC Project Authors. All rights reserved. |
+ * |
+ * Use of this source code is governed by a BSD-style license |
+ * that can be found in the LICENSE file in the root of the source |
+ * tree. An additional intellectual property rights grant can be found |
+ * in the file PATENTS. All contributing project authors may |
+ * be found in the AUTHORS file in the root of the source tree. |
+ */ |
+ |
+/* |
+ * linked_ptr - simple reference linked pointer |
+ * (like reference counting, just using a linked list of the references |
+ * instead of their count.) |
+ * |
+ * The implementation stores three pointers for every linked_ptr, but |
+ * does not allocate anything on the free store. |
+ */ |
+ |
+#ifndef WEBRTC_BASE_LINKED_PTR_H__ |
+#define WEBRTC_BASE_LINKED_PTR_H__ |
+ |
+namespace rtc { |
+ |
+/* For ANSI-challenged compilers, you may want to #define |
+ * NO_MEMBER_TEMPLATES, explicit or mutable */ |
+#define NO_MEMBER_TEMPLATES |
+ |
+template <class X> class linked_ptr |
+{ |
+public: |
+ |
+#ifndef NO_MEMBER_TEMPLATES |
+# define TEMPLATE_FUNCTION template <class Y> |
+ TEMPLATE_FUNCTION friend class linked_ptr<Y>; |
+#else |
+# define TEMPLATE_FUNCTION |
+ typedef X Y; |
+#endif |
+ |
+ typedef X element_type; |
+ |
+ explicit linked_ptr(X* p = 0) throw() |
+ : itsPtr(p) {itsPrev = itsNext = this;} |
+ ~linked_ptr() |
+ {release();} |
+ linked_ptr(const linked_ptr& r) throw() |
+ {acquire(r);} |
+ linked_ptr& operator=(const linked_ptr& r) |
+ { |
+ if (this != &r) { |
+ release(); |
+ acquire(r); |
+ } |
+ return *this; |
+ } |
+ |
+#ifndef NO_MEMBER_TEMPLATES |
+ template <class Y> friend class linked_ptr<Y>; |
+ template <class Y> linked_ptr(const linked_ptr<Y>& r) throw() |
+ {acquire(r);} |
+ template <class Y> linked_ptr& operator=(const linked_ptr<Y>& r) |
+ { |
+ if (this != &r) { |
+ release(); |
+ acquire(r); |
+ } |
+ return *this; |
+ } |
+#endif // NO_MEMBER_TEMPLATES |
+ |
+ X& operator*() const throw() {return *itsPtr;} |
+ X* operator->() const throw() {return itsPtr;} |
+ X* get() const throw() {return itsPtr;} |
+ bool unique() const throw() {return itsPrev ? itsPrev==this : true;} |
+ |
+private: |
+ X* itsPtr; |
+ mutable const linked_ptr* itsPrev; |
+ mutable const linked_ptr* itsNext; |
+ |
+ void acquire(const linked_ptr& r) throw() |
+ { // insert this to the list |
+ itsPtr = r.itsPtr; |
+ itsNext = r.itsNext; |
+ itsNext->itsPrev = this; |
+ itsPrev = &r; |
+#ifndef mutable |
+ r.itsNext = this; |
+#else // for ANSI-challenged compilers |
+ (const_cast<linked_ptr<X>*>(&r))->itsNext = this; |
+#endif |
+ } |
+ |
+#ifndef NO_MEMBER_TEMPLATES |
+ template <class Y> void acquire(const linked_ptr<Y>& r) throw() |
+ { // insert this to the list |
+ itsPtr = r.itsPtr; |
+ itsNext = r.itsNext; |
+ itsNext->itsPrev = this; |
+ itsPrev = &r; |
+#ifndef mutable |
+ r.itsNext = this; |
+#else // for ANSI-challenged compilers |
+ (const_cast<linked_ptr<X>*>(&r))->itsNext = this; |
+#endif |
+ } |
+#endif // NO_MEMBER_TEMPLATES |
+ |
+ void release() |
+ { // erase this from the list, delete if unique |
+ if (unique()) delete itsPtr; |
+ else { |
+ itsPrev->itsNext = itsNext; |
+ itsNext->itsPrev = itsPrev; |
+ itsPrev = itsNext = 0; |
+ } |
+ itsPtr = 0; |
+ } |
+}; |
+ |
+} // namespace rtc |
+ |
+#endif // WEBRTC_BASE_LINKED_PTR_H__ |
+ |