Re-land r93365 - add RefCountedString

base/memory/ref_counted_memory.h

Index: base/memory/ref_counted_memory.h
diff --git a/base/memory/ref_counted_memory.h b/base/memory/ref_counted_memory.h
index 1a0f51eec4aebf8784f7ed02e6b91c5964fb18c5..7438d573270d4321e024bb422a12aa0e6fcb550a 100644
--- a/base/memory/ref_counted_memory.h
+++ b/base/memory/ref_counted_memory.h
@@ -6,9 +6,11 @@
 #define BASE_MEMORY_REF_COUNTED_MEMORY_H_
 #pragma once
 
+#include <string>
 #include <vector>
 
 #include "base/base_api.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
@@ -40,11 +42,11 @@ class BASE_API RefCountedStaticMemory : public RefCountedMemory {
   RefCountedStaticMemory()
       : data_(NULL), length_(0) {}
   RefCountedStaticMemory(const unsigned char* data, size_t length)
-      : data_(data), length_(length) {}
+      : data_(length ? data : NULL), length_(length) {}
 
-  // Overriden from RefCountedMemory:
-  virtual const unsigned char* front() const;
-  virtual size_t size() const;
+  // Overridden from RefCountedMemory:
+  virtual const unsigned char* front() const OVERRIDE;
+  virtual size_t size() const OVERRIDE;
 
  private:
   const unsigned char* data_;
@@ -67,18 +69,51 @@ class BASE_API RefCountedBytes : public RefCountedMemory {
   // vector.)
   static RefCountedBytes* TakeVector(std::vector<unsigned char>* to_destroy);
 
-  // Overriden from RefCountedMemory:
-  virtual const unsigned char* front() const;
-  virtual size_t size() const;
+  // Overridden from RefCountedMemory:
+  virtual const unsigned char* front() const OVERRIDE;
+  virtual size_t size() const OVERRIDE;
 
-  std::vector<unsigned char> data;
+  const std::vector<unsigned char>& data() const { return data_; }
+  std::vector<unsigned char>& data() { return data_; }
 
- protected:
+ private:
   friend class base::RefCountedThreadSafe<RefCountedBytes>;
   virtual ~RefCountedBytes();
 
- private:
+  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_API 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_