Transfer the C++03 move-only type emulation into base/move.h and also make ScopedVector move-only.

base/memory/scoped_ptr.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Scopers help you manage ownership of a pointer, helping you easily manage the
 // a pointer within a scope, and automatically destroying the pointer at the
 // end of a scope.  There are two main classes you will use, which correspond
 // to the operators new/delete and new[]/delete[].
 //
 // Example usage (scoped_ptr):
@@ skipping 63 matching lines @@
 
 // This is an implementation designed to match the anticipated future TR2
 // implementation of the scoped_ptr class, and its closely-related brethren,
 // scoped_array, scoped_ptr_malloc.
 
 #include <assert.h>
 #include <stddef.h>
 #include <stdlib.h>
 
 #include "base/compiler_specific.h"
-
-// Macro with the boilerplate C++03 move emulation for a class.
-//
-// In C++11, this is done via rvalue references.  Here, we use C++03 move
-// emulation to fake an rvalue reference.  For a more thorough explanation
-// of the technique, see:
-//
-//   http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Move_Constructor
-//
-#define CPP_03_MOVE_EMULATION(scoper, field) \
- private: \
-  struct RValue { \
-    explicit RValue(scoper& obj) : obj_(obj) {} \
-    scoper& obj_; \
-  }; \
- public: \
-  operator RValue() { return RValue(*this); } \
-  scoper(RValue proxy) : field(proxy.obj_.release()) { } \
-  scoper& operator=(RValue proxy) { \
-    swap(proxy.obj_); \
-    return *this; \
-  } \
-  scoper Pass() { return scoper(RValue(*this)); }
+#include "base/move.h"
 
 // A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
 // automatically deletes the pointer it holds (if any).
 // That is, scoped_ptr<T> owns the T object that it points to.
 // Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to a T object.
 // Also like T*, scoped_ptr<T> is thread-compatible, and once you
 // dereference it, you get the thread safety guarantees of T.
 //
 // The size of a scoped_ptr is small:
 // sizeof(scoped_ptr<C>) == sizeof(C*)
 template <class C>
 class scoped_ptr {
+  MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr, RValue);
+
  public:
 
   // The element type
   typedef C element_type;
 
   // Constructor.  Defaults to initializing with NULL.
   // There is no way to create an uninitialized scoped_ptr.
   // The input parameter must be allocated with new.
   explicit scoped_ptr(C* p = NULL) : ptr_(p) { }
 
   // Constructor.  Allows construction from a scoped_ptr rvalue for a
   // convertible type.
   template <typename U>
-  scoped_ptr(scoped_ptr<U> other) : ptr_(other.release()) {
-  }
+  scoped_ptr(scoped_ptr<U> other) : ptr_(other.release()) { }
+
+  // Constructor.  Move constructor for C++03 move emulation of this type.
+  scoped_ptr(RValue& other) : ptr_(other.release()) { }
 
   // Destructor.  If there is a C object, delete it.
   // We don't need to test ptr_ == NULL because C++ does that for us.
   ~scoped_ptr() {
     enum { type_must_be_complete = sizeof(C) };
     delete ptr_;
   }
 
   // operator=.  Allows assignment from a scoped_ptr rvalue for a convertible
   // type.
   template <typename U>
   scoped_ptr& operator=(scoped_ptr<U> rhs) {
     reset(rhs.release());
     return *this;
   }
 
+  // operator=.  Move operator= for C++03 move emulation of this type.
+  scoped_ptr& operator=(RValue& rhs) {
+    swap(rhs);
+    return *this;
+  }
+
   // Reset.  Deletes the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
     if (p != ptr_) {
       enum { type_must_be_complete = sizeof(C) };
       delete ptr_;
       ptr_ = p;
     }
   }
@@ skipping 27 matching lines @@
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() WARN_UNUSED_RESULT {
     C* retVal = ptr_;
     ptr_ = NULL;
     return retVal;
   }
 
-  CPP_03_MOVE_EMULATION(scoped_ptr, ptr_);
-
  private:
   C* ptr_;
 
   // Forbid comparison of scoped_ptr types.  If C2 != C, it totally doesn't
   // make sense, and if C2 == C, it still doesn't make sense because you should
   // never have the same object owned by two different scoped_ptrs.
   template <class C2> bool operator==(scoped_ptr<C2> const& p2) const;
   template <class C2> bool operator!=(scoped_ptr<C2> const& p2) const;
 
-  // Disallow evil constructors.  Note that MUST NOT take a const& because we
-  // are implementing move semantics.  See the CPP_03_MOVE_EMULATION macro.
-  scoped_ptr(scoped_ptr&);
-  void operator=(scoped_ptr&);
 };
 
 // Free functions
 template <class C>
 void swap(scoped_ptr<C>& p1, scoped_ptr<C>& p2) {
   p1.swap(p2);
 }
 
 template <class C>
 bool operator==(C* p1, const scoped_ptr<C>& p2) {
   return p1 == p2.get();
 }
 
 template <class C>
 bool operator!=(C* p1, const scoped_ptr<C>& p2) {
   return p1 != p2.get();
 }
 
 // scoped_array<C> is like scoped_ptr<C>, except that the caller must allocate
 // with new [] and the destructor deletes objects with delete [].
 //
 // As with scoped_ptr<C>, a scoped_array<C> either points to an object
 // or is NULL.  A scoped_array<C> owns the object that it points to.
 // scoped_array<T> is thread-compatible, and once you index into it,
 // the returned objects have only the thread safety guarantees of T.
 //
 // Size: sizeof(scoped_array<C>) == sizeof(C*)
 template <class C>
 class scoped_array {
+  MOVE_ONLY_TYPE_FOR_CPP_03(scoped_array, RValue);
+
  public:
 
   // The element type
   typedef C element_type;
 
   // Constructor.  Defaults to initializing with NULL.
   // There is no way to create an uninitialized scoped_array.
   // The input parameter must be allocated with new [].
   explicit scoped_array(C* p = NULL) : array_(p) { }
 
+  // Constructor.  Move constructor for C++03 move emulation of this type.
+  scoped_array(RValue& other) : array_(other.release()) { }
+
   // Destructor.  If there is a C object, delete it.
   // We don't need to test ptr_ == NULL because C++ does that for us.
   ~scoped_array() {
     enum { type_must_be_complete = sizeof(C) };
     delete[] array_;
   }
 
+  // operator=.  Move operator= for C++03 move emulation of this type.
+  scoped_array& operator=(RValue& rhs) {
+    swap(rhs);
+    return *this;
+  }
+
   // Reset.  Deletes the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
     if (p != array_) {
       enum { type_must_be_complete = sizeof(C) };
       delete[] array_;
       array_ = p;
     }
   }
@@ skipping 29 matching lines @@
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() WARN_UNUSED_RESULT {
     C* retVal = array_;
     array_ = NULL;
     return retVal;
   }
 
-  CPP_03_MOVE_EMULATION(scoped_array, array_);
-
  private:
   C* array_;
 
   // Forbid comparison of different scoped_array types.
   template <class C2> bool operator==(scoped_array<C2> const& p2) const;
   template <class C2> bool operator!=(scoped_array<C2> const& p2) const;
-
-  // Disallow evil constructors.  Note that MUST NOT take a const& because we
-  // are implementing move semantics.  See the CPP_03_MOVE_EMULATION macro.
-  scoped_array(scoped_array&);
-  void operator=(scoped_array&);
 };
 
 // Free functions
 template <class C>
 void swap(scoped_array<C>& p1, scoped_array<C>& p2) {
   p1.swap(p2);
 }
 
 template <class C>
 bool operator==(C* p1, const scoped_array<C>& p2) {
@@ skipping 12 matching lines @@
   inline void operator()(void* x) const {
     free(x);
   }
 };
 
 // scoped_ptr_malloc<> is similar to scoped_ptr<>, but it accepts a
 // second template argument, the functor used to free the object.
 
 template<class C, class FreeProc = ScopedPtrMallocFree>
 class scoped_ptr_malloc {
+  MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr_malloc, RValue);
+
  public:
 
   // The element type
   typedef C element_type;
 
   // Constructor.  Defaults to initializing with NULL.
   // There is no way to create an uninitialized scoped_ptr.
   // The input parameter must be allocated with an allocator that matches the
   // Free functor.  For the default Free functor, this is malloc, calloc, or
   // realloc.
   explicit scoped_ptr_malloc(C* p = NULL): ptr_(p) {}
 
+  // Constructor.  Move constructor for C++03 move emulation of this type.
+  scoped_ptr_malloc(RValue& other) : ptr_(other.release()) { }
+
   // Destructor.  If there is a C object, call the Free functor.
   ~scoped_ptr_malloc() {
     reset();
   }
 
+  // operator=.  Move operator= for C++03 move emulation of this type.
+  scoped_ptr_malloc& operator=(RValue& rhs) {
+    swap(rhs);
+    return *this;
+  }
+
   // Reset.  Calls the Free functor on the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
     if (ptr_ != p) {
       FreeProc free_proc;
       free_proc(ptr_);
       ptr_ = p;
     }
   }
@@ skipping 39 matching lines @@
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() WARN_UNUSED_RESULT {
     C* tmp = ptr_;
     ptr_ = NULL;
     return tmp;
   }
 
-  CPP_03_MOVE_EMULATION(scoped_ptr_malloc, ptr_);
-
  private:
   C* ptr_;
 
   // no reason to use these: each scoped_ptr_malloc should have its own object
   template <class C2, class GP>
   bool operator==(scoped_ptr_malloc<C2, GP> const& p) const;
   template <class C2, class GP>
   bool operator!=(scoped_ptr_malloc<C2, GP> const& p) const;
-
-  // Disallow evil constructors.  Note that MUST NOT take a const& because we
-  // are implementing move semantics.  See the CPP_03_MOVE_EMULATION macro.
-  scoped_ptr_malloc(scoped_ptr_malloc&);
-  void operator=(scoped_ptr_malloc&);
 };
 
-#undef CPP_03_MOVE_EMULATION
-
 template<class C, class FP> inline
 void swap(scoped_ptr_malloc<C, FP>& a, scoped_ptr_malloc<C, FP>& b) {
   a.swap(b);
 }
 
 template<class C, class FP> inline
 bool operator==(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p == b.get();
 }
 
 template<class C, class FP> inline
 bool operator!=(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p != b.get();
 }
 
 #endif  // BASE_MEMORY_SCOPED_PTR_H_