// 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 NET_FTP_FTP_TRANSACTION_H_
#define NET_FTP_FTP_TRANSACTION_H_

#include <stdint.h>

#include "net/base/completion_once_callback.h"
#include "net/base/io_buffer.h"
#include "net/base/load_states.h"
#include "net/base/net_export.h"
#include "net/traffic_annotation/network_traffic_annotation.h"

namespace net {

class AuthCredentials;
class FtpResponseInfo;
class FtpRequestInfo;
class NetLogWithSource;

// Represents a single FTP transaction.
class NET_EXPORT_PRIVATE FtpTransaction {
 public:
  // Stops any pending IO and destroys the transaction object.
  virtual ~FtpTransaction() {}

  // Starts the FTP transaction (i.e., sends the FTP request).
  //
  // Returns OK if the transaction could be started synchronously, which means
  // that the request was served from the cache (only supported for directory
  // listings).  ERR_IO_PENDING is returned to indicate that |callback| will be
  // notified once response info is available or if an IO error occurs.  Any
  // other return value indicates that the transaction could not be started.
  //
  // Regardless of the return value, the caller is expected to keep the
  // request_info object alive until Destroy is called on the transaction.
  //
  // NOTE: The transaction is not responsible for deleting the callback object.
  //
  // Profiling information for the request is saved to |net_log| if non-NULL.
  virtual int Start(const FtpRequestInfo* request_info,
                    CompletionOnceCallback callback,
                    const NetLogWithSource& net_log,
                    const NetworkTrafficAnnotationTag& traffic_annotation) = 0;

  // Restarts the FTP transaction with authentication credentials.
  virtual int RestartWithAuth(const AuthCredentials& credentials,
                              CompletionOnceCallback callback) = 0;

  // Once response info is available for the transaction, response data may be
  // read by calling this method.
  //
  // Response data is copied into the given buffer and the number of bytes
  // copied is returned.  ERR_IO_PENDING is returned if response data is not yet
  // available.  |callback| is notified when the data copy completes, and it is
  // passed the number of bytes that were successfully copied.  Or, if a read
  // error occurs, |callback| is notified of the error.  Any other negative
  // return value indicates that the transaction could not be read.
  //
  // NOTE: The transaction is not responsible for deleting the callback object.
  //
  virtual int Read(IOBuffer* buf,
                   int buf_len,
                   CompletionOnceCallback callback) = 0;

  // Returns the response info for this transaction or NULL if the response
  // info is not available.
  virtual const FtpResponseInfo* GetResponseInfo() const = 0;

  // Returns the load state for this transaction.
  virtual LoadState GetLoadState() const = 0;

  // Returns the upload progress in bytes.  If there is no upload data,
  // zero will be returned.
  virtual uint64_t GetUploadProgress() const = 0;
};

}  // namespace net

#endif  // NET_FTP_FTP_TRANSACTION_H_