Branch CEF3 files from /branches/cef3 to /trunk/cef3 (issue #564).

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@571 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

include/internal/cef_ptr.h

@@ -0,0 +1,199 @@
+// Copyright (c) 2008 Marshall A. Greenblatt. Portions Copyright (c)
+// 2006-2008 Google Inc. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the name Chromium Embedded
+// Framework nor the names of its contributors may be used to endorse
+// or promote products derived from this software without specific prior
+// written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+#ifndef CEF_INCLUDE_INTERNAL_CEF_PTR_H_
+#define CEF_INCLUDE_INTERNAL_CEF_PTR_H_
+#pragma once
+
+#include <stddef.h>
+
+///
+// Smart pointer implementation borrowed from base/ref_counted.h
+// <p>
+// A smart pointer class for reference counted objects.  Use this class instead
+// of calling AddRef and Release manually on a reference counted object to
+// avoid common memory leaks caused by forgetting to Release an object
+// reference.  Sample usage:
+// <pre>
+//   class MyFoo : public CefBase {
+//    ...
+//   };
+//
+//   void some_function() {
+//     // The MyFoo object that |foo| represents starts with a single
+//     // reference.
+//     CefRefPtr&lt;MyFoo&gt; foo = new MyFoo();
+//     foo-&gt;Method(param);
+//     // |foo| is released when this function returns
+//   }
+//
+//   void some_other_function() {
+//     CefRefPtr&lt;MyFoo&gt; foo = new MyFoo();
+//     ...
+//     foo = NULL;  // explicitly releases |foo|
+//     ...
+//     if (foo)
+//       foo-&gt;Method(param);
+//   }
+// </pre>
+// The above examples show how CefRefPtr&lt;T&gt; acts like a pointer to T.
+// Given two CefRefPtr&lt;T&gt; classes, it is also possible to exchange
+// references between the two objects, like so:
+// <pre>
+//   {
+//     CefRefPtr&lt;MyFoo&gt; a = new MyFoo();
+//     CefRefPtr&lt;MyFoo&gt; b;
+//
+//     b.swap(a);
+//     // now, |b| references the MyFoo object, and |a| references NULL.
+//   }
+// </pre>
+// To make both |a| and |b| in the above example reference the same MyFoo
+// object, simply use the assignment operator:
+// <pre>
+//   {
+//     CefRefPtr&lt;MyFoo&gt; a = new MyFoo();
+//     CefRefPtr&lt;MyFoo&gt; b;
+//
+//     b = a;
+//     // now, |a| and |b| each own a reference to the same MyFoo object.
+//     // the reference count of the underlying MyFoo object will be 2.
+//   }
+// </pre>
+// Reference counted objects can also be passed as function parameters and
+// used as function return values:
+// <pre>
+//   void some_func_with_param(CefRefPtr&lt;MyFoo&gt; param) {
+//     // A reference is added to the MyFoo object that |param| represents
+//     // during the scope of some_func_with_param() and released when
+//     // some_func_with_param() goes out of scope.
+//   }
+//
+//   CefRefPtr&lt;MyFoo&gt; some_func_with_retval() {
+//     // The MyFoo object that |foox| represents starts with a single
+//     // reference.
+//     CefRefPtr&lt;MyFoo&gt; foox = new MyFoo();
+//
+//     // Creating the return value adds an additional reference.
+//     return foox;
+//
+//     // When some_func_with_retval() goes out of scope the original |foox|
+//     // reference is released.
+//   }
+//
+//   void and_another_function() {
+//     CefRefPtr&lt;MyFoo&gt; foo = new MyFoo();
+//
+//     // pass |foo| as a parameter.
+//     some_function(foo);
+//
+//     CefRefPtr&lt;MyFoo&gt; foo2 = some_func_with_retval();
+//     // Now, since we kept a reference to the some_func_with_retval() return
+//     // value, |foo2| is the only class pointing to the MyFoo object created
+//     in some_func_with_retval(), and it has a reference count of 1.
+//
+//     some_func_with_retval();
+//     // Now, since we didn't keep a reference to the some_func_with_retval()
+//     // return value, the MyFoo object created in some_func_with_retval()
+//     // will automatically be released.
+//   }
+// </pre>
+// And in standard containers:
+// <pre>
+//   {
+//      // Create a vector that holds MyFoo objects.
+//      std::vector&lt;CefRefPtr&lt;MyFoo&gt; &gt; MyFooVec;
+//
+//     // The MyFoo object that |foo| represents starts with a single
+//     // reference.
+//     CefRefPtr&lt;MyFoo&gt; foo = new MyFoo();
+//
+//     // When the MyFoo object is added to |MyFooVec| the reference count
+//     // is increased to 2.
+//     MyFooVec.push_back(foo);
+//   }
+// </pre>
+// </p>
+///
+template <class T>
+class CefRefPtr {
+ public:
+  CefRefPtr() : ptr_(NULL) {
+  }
+
+  CefRefPtr(T* p) : ptr_(p) {  // NOLINT(runtime/explicit)
+    if (ptr_)
+      ptr_->AddRef();
+  }
+
+  CefRefPtr(const CefRefPtr<T>& r) : ptr_(r.ptr_) {
+    if (ptr_)
+      ptr_->AddRef();
+  }
+
+  ~CefRefPtr() {
+    if (ptr_)
+      ptr_->Release();
+  }
+
+  T* get() const { return ptr_; }
+  operator T*() const { return ptr_; }
+  T* operator->() const { return ptr_; }
+
+  CefRefPtr<T>& operator=(T* p) {
+    // AddRef first so that self assignment should work
+    if (p)
+      p->AddRef();
+    if (ptr_ )
+      ptr_ ->Release();
+    ptr_ = p;
+    return *this;
+  }
+
+  CefRefPtr<T>& operator=(const CefRefPtr<T>& r) {
+    return *this = r.ptr_;
+  }
+
+  void swap(T** pp) {
+    T* p = ptr_;
+    ptr_ = *pp;
+    *pp = p;
+  }
+
+  void swap(CefRefPtr<T>& r) {
+    swap(&r.ptr_);  // NOLINT(build/include_what_you_use)
+  }
+
+ private:
+  T* ptr_;
+};
+
+#endif  // CEF_INCLUDE_INTERNAL_CEF_PTR_H_