src/scoped_ptr.h - platform/art - Git at Google

 // Copyright 2010 Google
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #ifndef ART_SRC_SCOPED_PTR_H_
 #define ART_SRC_SCOPED_PTR_H_

 //  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, and make_scoped_ptr.

 #include "macros.h"

 #include <assert.h>
 #include <stdlib.h>

 #include <algorithm>
 #include <cstddef>

 template <class C> class scoped_ptr;
 template <class C, class Free> class scoped_ptr_malloc;
 template <class C> class scoped_array;

 template <class C>
 scoped_ptr<C> make_scoped_ptr(C * param);

 // 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.
 //
 // The size of a scoped_ptr is small:
 // sizeof(scoped_ptr<C>) == sizeof(C*)
 template <class C>
 class scoped_ptr {
  public:

   // The element type
   typedef C element_type;

   // Constructor.  Defaults to intializing 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) { }

   // 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_;
   }

   // 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;
     }
   }

   // Accessors to get the owned object.
   // operator* and operator-> will assert() if there is no current object.
   C& operator*() const {
     assert(ptr_ != NULL);
     return *ptr_;
   }
   C* operator->() const  {
     assert(ptr_ != NULL);
     return ptr_;
   }
   C* get() const { return ptr_; }

   // Comparison operators.
   // These return whether two scoped_ptr refer to the same object, not just to
   // two different but equal objects.
   bool operator==(C* p) const { return ptr_ == p; }
   bool operator!=(C* p) const { return ptr_ != p; }

   // Swap two scoped pointers.
   void swap(scoped_ptr& p2) {
     C* tmp = ptr_;
     ptr_ = p2.ptr_;
     p2.ptr_ = tmp;
   }

   // Release a pointer.
   // 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() {
     C* retVal = ptr_;
     ptr_ = NULL;
     return retVal;
   }

  private:
   C* ptr_;

   // friend class that can access copy ctor (although if it actually
   // calls a copy ctor, there will be a problem) see below
   friend scoped_ptr<C> make_scoped_ptr<C>(C *p);

   // 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_COPY_AND_ASSIGN(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();
 }

 template <class C>
 scoped_ptr<C> make_scoped_ptr(C *p) {
   // This does nothing but to return a scoped_ptr of the type that the passed
   // pointer is of.  (This eliminates the need to specify the name of T when
   // making a scoped_ptr that is used anonymously/temporarily.)  From an
   // access control point of view, we construct an unnamed scoped_ptr here
   // which we return and thus copy-construct.  Hence, we need to have access
   // to scoped_ptr::scoped_ptr(scoped_ptr const &).  However, it is guaranteed
   // that we never actually call the copy constructor, which is a good thing
   // as we would call the temporary's object destructor (and thus delete p)
   // if we actually did copy some object, here.
   return scoped_ptr<C>(p);
 }

 // 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.
 //
 // Size: sizeof(scoped_array<C>) == sizeof(C*)
 template <class C>
 class scoped_array {
  public:

   // The element type
   typedef C element_type;

   // Constructor.  Defaults to intializing 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) { }

   // 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_;
   }

   // 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;
     }
   }

   // Get one element of the current object.
   // Will assert() if there is no current object, or index i is negative.
   C& operator[](std::ptrdiff_t i) const {
     assert(i >= 0);
     assert(array_ != NULL);
     return array_[i];
   }

   // Get a pointer to the zeroth element of the current object.
   // If there is no current object, return NULL.
   C* get() const {
     return array_;
   }

   // Comparison operators.
   // These return whether two scoped_array refer to the same object, not just to
   // two different but equal objects.
   bool operator==(C* p) const { return array_ == p; }
   bool operator!=(C* p) const { return array_ != p; }

   // Swap two scoped arrays.
   void swap(scoped_array& p2) {
     C* tmp = array_;
     array_ = p2.array_;
     p2.array_ = tmp;
   }

   // Release an array.
   // 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() {
     C* retVal = array_;
     array_ = NULL;
     return retVal;
   }

  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_COPY_AND_ASSIGN(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) {
   return p1 == p2.get();
 }

 template <class C>
 bool operator!=(C* p1, const scoped_array<C>& p2) {
   return p1 != p2.get();
 }

 // This class wraps the c library function free() in a class that can be
 // passed as a template argument to scoped_ptr_malloc below.
 class ScopedPtrMallocFree {
  public:
   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 {
  public:

   // The element type
   typedef C element_type;

   // Constructor.  Defaults to intializing 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) {}

   // Destructor.  If there is a C object, call the Free functor.
   ~scoped_ptr_malloc() {
     free_(ptr_);
   }

   // 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) {
       free_(ptr_);
       ptr_ = p;
     }
   }

   // Get the current object.
   // operator* and operator-> will cause an assert() failure if there is
   // no current object.
   C& operator*() const {
     assert(ptr_ != NULL);
     return *ptr_;
   }

   C* operator->() const {
     assert(ptr_ != NULL);
     return ptr_;
   }

   C* get() const {
     return ptr_;
   }

   // Comparison operators.
   // These return whether a scoped_ptr_malloc and a plain pointer refer
   // to the same object, not just to two different but equal objects.
   // For compatibility wwith the boost-derived implementation, these
   // take non-const arguments.
   bool operator==(C* p) const {
     return ptr_ == p;
   }

   bool operator!=(C* p) const {
     return ptr_ != p;
   }

   // Swap two scoped pointers.
   void swap(scoped_ptr_malloc & b) {
     C* tmp = b.ptr_;
     b.ptr_ = ptr_;
     ptr_ = tmp;
   }

   // Release a pointer.
   // 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() {
     C* tmp = ptr_;
     ptr_ = NULL;
     return tmp;
   }

  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;

   static FreeProc const free_;

   DISALLOW_COPY_AND_ASSIGN(scoped_ptr_malloc);
 };

 template<class C, class FP>
 FP const scoped_ptr_malloc<C, FP>::free_ = FP();

 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  // ART_SRC_SCOPED_PTR_H_
	// Copyright 2010 Google
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#ifndef ART_SRC_SCOPED_PTR_H_
	#define ART_SRC_SCOPED_PTR_H_

	// 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, and make_scoped_ptr.

	#include "macros.h"

	#include <assert.h>
	#include <stdlib.h>

	#include <algorithm>
	#include <cstddef>

	template <class C> class scoped_ptr;
	template <class C, class Free> class scoped_ptr_malloc;
	template <class C> class scoped_array;

	template <class C>
	scoped_ptr<C> make_scoped_ptr(C * param);

	// 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.
	//
	// The size of a scoped_ptr is small:
	// sizeof(scoped_ptr<C>) == sizeof(C*)
	template <class C>
	class scoped_ptr {
	public:

	// The element type
	typedef C element_type;

	// Constructor. Defaults to intializing 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) { }

	// 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_;
	}

	// 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;
	}
	}

	// Accessors to get the owned object.
	// operator* and operator-> will assert() if there is no current object.
	C& operator*() const {
	assert(ptr_ != NULL);
	return *ptr_;
	}
	C* operator->() const {
	assert(ptr_ != NULL);
	return ptr_;
	}
	C* get() const { return ptr_; }

	// Comparison operators.
	// These return whether two scoped_ptr refer to the same object, not just to
	// two different but equal objects.
	bool operator==(C* p) const { return ptr_ == p; }
	bool operator!=(C* p) const { return ptr_ != p; }

	// Swap two scoped pointers.
	void swap(scoped_ptr& p2) {
	C* tmp = ptr_;
	ptr_ = p2.ptr_;
	p2.ptr_ = tmp;
	}

	// Release a pointer.
	// 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() {
	C* retVal = ptr_;
	ptr_ = NULL;
	return retVal;
	}

	private:
	C* ptr_;

	// friend class that can access copy ctor (although if it actually
	// calls a copy ctor, there will be a problem) see below
	friend scoped_ptr<C> make_scoped_ptr<C>(C *p);

	// 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_COPY_AND_ASSIGN(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();
	}

	template <class C>
	scoped_ptr<C> make_scoped_ptr(C *p) {
	// This does nothing but to return a scoped_ptr of the type that the passed
	// pointer is of. (This eliminates the need to specify the name of T when
	// making a scoped_ptr that is used anonymously/temporarily.) From an
	// access control point of view, we construct an unnamed scoped_ptr here
	// which we return and thus copy-construct. Hence, we need to have access
	// to scoped_ptr::scoped_ptr(scoped_ptr const &). However, it is guaranteed
	// that we never actually call the copy constructor, which is a good thing
	// as we would call the temporary's object destructor (and thus delete p)
	// if we actually did copy some object, here.
	return scoped_ptr<C>(p);
	}

	// 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.
	//
	// Size: sizeof(scoped_array<C>) == sizeof(C*)
	template <class C>
	class scoped_array {
	public:

	// The element type
	typedef C element_type;

	// Constructor. Defaults to intializing 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) { }

	// 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_;
	}

	// 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;
	}
	}

	// Get one element of the current object.
	// Will assert() if there is no current object, or index i is negative.
	C& operator[](std::ptrdiff_t i) const {
	assert(i >= 0);
	assert(array_ != NULL);
	return array_[i];
	}

	// Get a pointer to the zeroth element of the current object.
	// If there is no current object, return NULL.
	C* get() const {
	return array_;
	}

	// Comparison operators.
	// These return whether two scoped_array refer to the same object, not just to
	// two different but equal objects.
	bool operator==(C* p) const { return array_ == p; }
	bool operator!=(C* p) const { return array_ != p; }

	// Swap two scoped arrays.
	void swap(scoped_array& p2) {
	C* tmp = array_;
	array_ = p2.array_;
	p2.array_ = tmp;
	}

	// Release an array.
	// 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() {
	C* retVal = array_;
	array_ = NULL;
	return retVal;
	}

	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_COPY_AND_ASSIGN(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) {
	return p1 == p2.get();
	}

	template <class C>
	bool operator!=(C* p1, const scoped_array<C>& p2) {
	return p1 != p2.get();
	}

	// This class wraps the c library function free() in a class that can be
	// passed as a template argument to scoped_ptr_malloc below.
	class ScopedPtrMallocFree {
	public:
	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 {
	public:

	// The element type
	typedef C element_type;

	// Constructor. Defaults to intializing 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) {}

	// Destructor. If there is a C object, call the Free functor.
	~scoped_ptr_malloc() {
	free_(ptr_);
	}

	// 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) {
	free_(ptr_);
	ptr_ = p;
	}
	}

	// Get the current object.
	// operator* and operator-> will cause an assert() failure if there is
	// no current object.
	C& operator*() const {
	assert(ptr_ != NULL);
	return *ptr_;
	}

	C* operator->() const {
	assert(ptr_ != NULL);
	return ptr_;
	}

	C* get() const {
	return ptr_;
	}

	// Comparison operators.
	// These return whether a scoped_ptr_malloc and a plain pointer refer
	// to the same object, not just to two different but equal objects.
	// For compatibility wwith the boost-derived implementation, these
	// take non-const arguments.
	bool operator==(C* p) const {
	return ptr_ == p;
	}

	bool operator!=(C* p) const {
	return ptr_ != p;
	}

	// Swap two scoped pointers.
	void swap(scoped_ptr_malloc & b) {
	C* tmp = b.ptr_;
	b.ptr_ = ptr_;
	ptr_ = tmp;
	}

	// Release a pointer.
	// 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() {
	C* tmp = ptr_;
	ptr_ = NULL;
	return tmp;
	}

	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;

	static FreeProc const free_;

	DISALLOW_COPY_AND_ASSIGN(scoped_ptr_malloc);
	};

	template<class C, class FP>
	FP const scoped_ptr_malloc<C, FP>::free_ = FP();

	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 // ART_SRC_SCOPED_PTR_H_