Remove //net (except for Android test stuff) and sdch

net/base/io_buffer.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.
-
-#ifndef NET_BASE_IO_BUFFER_H_
-#define NET_BASE_IO_BUFFER_H_
-
-#include <string>
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/pickle.h"
-#include "net/base/net_export.h"
-
-namespace net {
-
-// IOBuffers are reference counted data buffers used for easier asynchronous
-// IO handling.
-//
-// They are often used as the destination buffers for Read() operations, or as
-// the source buffers for Write() operations.
-//
-// IMPORTANT: Never re-use an IOBuffer after cancelling the IO operation that
-//            was using it, since this may lead to memory corruption!
-//
-// -----------------------
-// Ownership of IOBuffers:
-// -----------------------
-//
-// Although IOBuffers are RefCountedThreadSafe, they are not intended to be
-// used as a shared buffer, nor should they be used simultaneously across
-// threads. The fact that they are reference counted is an implementation
-// detail for allowing them to outlive cancellation of asynchronous
-// operations.
-//
-// Instead, think of the underlying |char*| buffer contained by the IOBuffer
-// as having exactly one owner at a time.
-//
-// Whenever you call an asynchronous operation that takes an IOBuffer,
-// ownership is implicitly transferred to the called function, until the
-// operation has completed (at which point it transfers back to the caller).
-//
-//     ==> The IOBuffer's data should NOT be manipulated, destroyed, or read
-//         until the operation has completed.
-//
-//     ==> Cancellation does NOT count as completion. If an operation using
-//         an IOBuffer is cancelled, the caller should release their
-//         reference to this IOBuffer at the time of cancellation since
-//         they can no longer use it.
-//
-// For instance, if you were to call a Read() operation on some class which
-// takes an IOBuffer, and then delete that class (which generally will
-// trigger cancellation), the IOBuffer which had been passed to Read() should
-// never be re-used.
-//
-// This usage contract is assumed by any API which takes an IOBuffer, even
-// though it may not be explicitly mentioned in the function's comments.
-//
-// -----------------------
-// Motivation
-// -----------------------
-//
-// The motivation for transferring ownership during cancellation is
-// to make it easier to work with un-cancellable operations.
-//
-// For instance, let's say under the hood your API called out to the
-// operating system's synchronous ReadFile() function on a worker thread.
-// When cancelling through our asynchronous interface, we have no way of
-// actually aborting the in progress ReadFile(). We must let it keep running,
-// and hence the buffer it was reading into must remain alive. Using
-// reference counting we can add a reference to the IOBuffer and make sure
-// it is not destroyed until after the synchronous operation has completed.
-class NET_EXPORT IOBuffer : public base::RefCountedThreadSafe<IOBuffer> {
- public:
-  IOBuffer();
-  explicit IOBuffer(int buffer_size);
-
-  char* data() { return data_; }
-
- protected:
-  friend class base::RefCountedThreadSafe<IOBuffer>;
-
-  // Only allow derived classes to specify data_.
-  // In all other cases, we own data_, and must delete it at destruction time.
-  explicit IOBuffer(char* data);
-
-  virtual ~IOBuffer();
-
-  char* data_;
-};
-
-// This version stores the size of the buffer so that the creator of the object
-// doesn't have to keep track of that value.
-// NOTE: This doesn't mean that we want to stop sending the size as an explicit
-// argument to IO functions. Please keep using IOBuffer* for API declarations.
-class NET_EXPORT IOBufferWithSize : public IOBuffer {
- public:
-  explicit IOBufferWithSize(int size);
-
-  int size() const { return size_; }
-
- protected:
-  // Purpose of this constructor is to give a subclass access to the base class
-  // constructor IOBuffer(char*) thus allowing subclass to use underlying
-  // memory it does not own.
-  IOBufferWithSize(char* data, int size);
-  ~IOBufferWithSize() override;
-
-  int size_;
-};
-
-// This is a read only IOBuffer.  The data is stored in a string and
-// the IOBuffer interface does not provide a proper way to modify it.
-class NET_EXPORT StringIOBuffer : public IOBuffer {
- public:
-  explicit StringIOBuffer(const std::string& s);
-  explicit StringIOBuffer(scoped_ptr<std::string> s);
-
-  int size() const { return static_cast<int>(string_data_.size()); }
-
- private:
-  ~StringIOBuffer() override;
-
-  std::string string_data_;
-};
-
-// This version wraps an existing IOBuffer and provides convenient functions
-// to progressively read all the data.
-//
-// DrainableIOBuffer is useful when you have an IOBuffer that contains data
-// to be written progressively, and Write() function takes an IOBuffer rather
-// than char*. DrainableIOBuffer can be used as follows:
-//
-// // payload is the IOBuffer containing the data to be written.
-// buf = new DrainableIOBuffer(payload, payload_size);
-//
-// while (buf->BytesRemaining() > 0) {
-//   // Write() takes an IOBuffer. If it takes char*, we could
-//   // simply use the regular IOBuffer like payload->data() + offset.
-//   int bytes_written = Write(buf, buf->BytesRemaining());
-//   buf->DidConsume(bytes_written);
-// }
-//
-class NET_EXPORT DrainableIOBuffer : public IOBuffer {
- public:
-  DrainableIOBuffer(IOBuffer* base, int size);
-
-  // DidConsume() changes the |data_| pointer so that |data_| always points
-  // to the first unconsumed byte.
-  void DidConsume(int bytes);
-
-  // Returns the number of unconsumed bytes.
-  int BytesRemaining() const;
-
-  // Returns the number of consumed bytes.
-  int BytesConsumed() const;
-
-  // Seeks to an arbitrary point in the buffer. The notion of bytes consumed
-  // and remaining are updated appropriately.
-  void SetOffset(int bytes);
-
-  int size() const { return size_; }
-
- private:
-  ~DrainableIOBuffer() override;
-
-  scoped_refptr<IOBuffer> base_;
-  int size_;
-  int used_;
-};
-
-// This version provides a resizable buffer and a changeable offset.
-//
-// GrowableIOBuffer is useful when you read data progressively without
-// knowing the total size in advance. GrowableIOBuffer can be used as
-// follows:
-//
-// buf = new GrowableIOBuffer;
-// buf->SetCapacity(1024);  // Initial capacity.
-//
-// while (!some_stream->IsEOF()) {
-//   // Double the capacity if the remaining capacity is empty.
-//   if (buf->RemainingCapacity() == 0)
-//     buf->SetCapacity(buf->capacity() * 2);
-//   int bytes_read = some_stream->Read(buf, buf->RemainingCapacity());
-//   buf->set_offset(buf->offset() + bytes_read);
-// }
-//
-class NET_EXPORT GrowableIOBuffer : public IOBuffer {
- public:
-  GrowableIOBuffer();
-
-  // realloc memory to the specified capacity.
-  void SetCapacity(int capacity);
-  int capacity() { return capacity_; }
-
-  // |offset| moves the |data_| pointer, allowing "seeking" in the data.
-  void set_offset(int offset);
-  int offset() { return offset_; }
-
-  int RemainingCapacity();
-  char* StartOfBuffer();
-
- private:
-  ~GrowableIOBuffer() override;
-
-  scoped_ptr<char, base::FreeDeleter> real_data_;
-  int capacity_;
-  int offset_;
-};
-
-// This versions allows a pickle to be used as the storage for a write-style
-// operation, avoiding an extra data copy.
-class NET_EXPORT PickledIOBuffer : public IOBuffer {
- public:
-  PickledIOBuffer();
-
-  Pickle* pickle() { return &pickle_; }
-
-  // Signals that we are done writing to the pickle and we can use it for a
-  // write-style IO operation.
-  void Done();
-
- private:
-  ~PickledIOBuffer() override;
-
-  Pickle pickle_;
-};
-
-// This class allows the creation of a temporary IOBuffer that doesn't really
-// own the underlying buffer. Please use this class only as a last resort.
-// A good example is the buffer for a synchronous operation, where we can be
-// sure that nobody is keeping an extra reference to this object so the lifetime
-// of the buffer can be completely managed by its intended owner.
-class NET_EXPORT WrappedIOBuffer : public IOBuffer {
- public:
-  explicit WrappedIOBuffer(const char* data);
-
- protected:
-  ~WrappedIOBuffer() override;
-};
-
-}  // namespace net
-
-#endif  // NET_BASE_IO_BUFFER_H_