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+// Copyright (c) 2011 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.
+
+#ifndef BASE_MEMORY_REF_COUNTED_MEMORY_H_
+#define BASE_MEMORY_REF_COUNTED_MEMORY_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+
+// TODO(erg): The contents of this file should be in a namespace. This would
+// require touching >100 files in chrome/ though.
+
+// A generic interface to memory. This object is reference counted because one
+// of its two subclasses own the data they carry, and we need to have
+// heterogeneous containers of these two types of memory.
+class BASE_EXPORT RefCountedMemory
+ : public base::RefCountedThreadSafe<RefCountedMemory> {
+ public:
+ // Retrieves a pointer to the beginning of the data we point to. If the data
+ // is empty, this will return NULL.
+ virtual const unsigned char* front() const = 0;
+
+ // Size of the memory pointed to.
+ virtual size_t size() const = 0;
+
+ protected:
+ friend class base::RefCountedThreadSafe<RefCountedMemory>;
+ RefCountedMemory();
+ virtual ~RefCountedMemory();
+};
+
+// An implementation of RefCountedMemory, where the ref counting does not
+// matter.
+class BASE_EXPORT RefCountedStaticMemory : public RefCountedMemory {
+ public:
+ RefCountedStaticMemory()
+ : data_(NULL), length_(0) {}
+ RefCountedStaticMemory(const unsigned char* data, size_t length)
+ : data_(length ? data : NULL), length_(length) {}
+
+ // Overridden from RefCountedMemory:
+ virtual const unsigned char* front() const OVERRIDE;
+ virtual size_t size() const OVERRIDE;
+
+ private:
+ const unsigned char* data_;
+ size_t length_;
+
+ DISALLOW_COPY_AND_ASSIGN(RefCountedStaticMemory);
+};
+
+// An implementation of RefCountedMemory, where we own our the data in a
+// vector.
+class BASE_EXPORT RefCountedBytes : public RefCountedMemory {
+ public:
+ RefCountedBytes();
+
+ // Constructs a RefCountedBytes object by _copying_ from |initializer|.
+ RefCountedBytes(const std::vector<unsigned char>& initializer);
+
+ // Constructs a RefCountedBytes object by performing a swap. (To non
+ // destructively build a RefCountedBytes, use the constructor that takes a
+ // vector.)
+ static RefCountedBytes* TakeVector(std::vector<unsigned char>* to_destroy);
+
+ // Overridden from RefCountedMemory:
+ virtual const unsigned char* front() const OVERRIDE;
+ virtual size_t size() const OVERRIDE;
+
+ const std::vector<unsigned char>& data() const { return data_; }
+ std::vector<unsigned char>& data() { return data_; }
+
+ private:
+ friend class base::RefCountedThreadSafe<RefCountedBytes>;
+ virtual ~RefCountedBytes();
+
+ std::vector<unsigned char> data_;
+
+ DISALLOW_COPY_AND_ASSIGN(RefCountedBytes);
+};
+
+namespace base {
+
+// An implementation of RefCountedMemory, where the bytes are stored in an STL
+// string. Use this if your data naturally arrives in that format.
+class BASE_EXPORT RefCountedString : public RefCountedMemory {
+ public:
+ RefCountedString();
+
+ // Constructs a RefCountedString object by performing a swap. (To non
+ // destructively build a RefCountedString, use the default constructor and
+ // copy into object->data()).
+ static RefCountedString* TakeString(std::string* to_destroy);
+
+ // Overridden from RefCountedMemory:
+ virtual const unsigned char* front() const OVERRIDE;
+ virtual size_t size() const OVERRIDE;
+
+ const std::string& data() const { return data_; }
+ std::string& data() { return data_; }
+
+ private:
+ friend class base::RefCountedThreadSafe<RefCountedString>;
+ virtual ~RefCountedString();
+
+ std::string data_;
+
+ DISALLOW_COPY_AND_ASSIGN(RefCountedString);
+};
+
+} // namespace base
+
+#endif // BASE_MEMORY_REF_COUNTED_MEMORY_H_