1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_REF_COUNTED_MEMORY_H_ 6 #define BASE_REF_COUNTED_MEMORY_H_ 7 8 #include <vector> 9 10 #include "base/ref_counted.h" 11 12 // TODO(erg): The contents of this file should be in a namespace. This would 13 // require touching >100 files in chrome/ though. 14 15 // A generic interface to memory. This object is reference counted because one 16 // of its two subclasses own the data they carry, and we need to have 17 // heterogeneous containers of these two types of memory. 18 class RefCountedMemory : public base::RefCountedThreadSafe<RefCountedMemory> { 19 public: 20 // Retrieves a pointer to the beginning of the data we point to. If the data 21 // is empty, this will return NULL. 22 virtual const unsigned char* front() const = 0; 23 24 // Size of the memory pointed to. 25 virtual size_t size() const = 0; 26 27 protected: 28 friend class base::RefCountedThreadSafe<RefCountedMemory>; 29 ~RefCountedMemory()30 virtual ~RefCountedMemory() {} 31 }; 32 33 // An implementation of RefCountedMemory, where the ref counting does not 34 // matter. 35 class RefCountedStaticMemory : public RefCountedMemory { 36 public: RefCountedStaticMemory()37 RefCountedStaticMemory() 38 : data_(NULL), length_(0) {} RefCountedStaticMemory(const unsigned char * data,size_t length)39 RefCountedStaticMemory(const unsigned char* data, size_t length) 40 : data_(data), length_(length) {} 41 front()42 virtual const unsigned char* front() const { return data_; } size()43 virtual size_t size() const { return length_; } 44 45 private: 46 const unsigned char* data_; 47 size_t length_; 48 49 DISALLOW_COPY_AND_ASSIGN(RefCountedStaticMemory); 50 }; 51 52 // An implementation of RefCountedMemory, where we own our the data in a 53 // vector. 54 class RefCountedBytes : public RefCountedMemory { 55 public: 56 // Constructs a RefCountedBytes object by performing a swap. (To non 57 // destructively build a RefCountedBytes, use the constructor that takes a 58 // vector.) TakeVector(std::vector<unsigned char> * to_destroy)59 static RefCountedBytes* TakeVector(std::vector<unsigned char>* to_destroy) { 60 RefCountedBytes* bytes = new RefCountedBytes; 61 bytes->data.swap(*to_destroy); 62 return bytes; 63 } 64 RefCountedBytes()65 RefCountedBytes() {} 66 67 // Constructs a RefCountedBytes object by _copying_ from |initializer|. RefCountedBytes(const std::vector<unsigned char> & initializer)68 RefCountedBytes(const std::vector<unsigned char>& initializer) 69 : data(initializer) {} 70 front()71 virtual const unsigned char* front() const { 72 // STL will assert if we do front() on an empty vector, but calling code 73 // expects a NULL. 74 return size() ? &data.front() : NULL; 75 } size()76 virtual size_t size() const { return data.size(); } 77 78 std::vector<unsigned char> data; 79 80 private: 81 DISALLOW_COPY_AND_ASSIGN(RefCountedBytes); 82 }; 83 84 #endif // BASE_REF_COUNTED_MEMORY_H_ 85