/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_USB_API_ADB_IO_COMPLETION_H__
#define ANDROID_USB_API_ADB_IO_COMPLETION_H__
/** \file
  This file consists of declaration of class AdbIOCompletion that encapsulates
  a wrapper around OVERLAPPED Win32 structure returned from asynchronous I/O
  requests.
*/

#include "adb_io_object.h"

/** Class AdbIOCompletion encapsulates encapsulates a wrapper around
  OVERLAPPED Win32 structure returned from asynchronous I/O requests.
  A handle to this object is returned to the caller of each successful
  asynchronous I/O request. Just like all other handles this handle
  must be closed after it's no longer needed.
*/
class AdbIOCompletion : public AdbObjectHandle {
 public:
  /** \brief Constructs the object
    
    @param parent_io_obj[in] Parent I/O object that created this instance.
           Parent object will be referenced in this object's constructur and
           released in the destructor.
    @param is_write_ctl[in] Flag indicating whether or not this completion
           object is created for ADB_IOCTL_BULK_WRITE I/O.
    @param event_hndl[in] Event handle that should be signaled when I/O
           completes. Can be NULL. If it's not NULL this handle will be
           used to initialize OVERLAPPED structure for this object.
  */
  AdbIOCompletion(AdbIOObject* parent_io_obj,
                  bool is_write_ctl,
                  ULONG expected_trans_size,
                  HANDLE event_hndl);

 protected:
  /** \brief Destructs the object.

    parent_io_object_ will be dereferenced here.
    We hide destructor in order to prevent ourseves from accidentaly allocating
    instances on the stack. If such attemp occur, compiler will error.
  */
  virtual ~AdbIOCompletion();

 public:
  /** \brief Gets overlapped I/O result

    @param ovl_data[out] Buffer for the copy of this object's OVERLAPPED
           structure. Can be NULL.
    @param bytes_transferred[out] Pointer to a variable that receives the
           number of bytes that were actually transferred by a read or write
           operation. See SDK doc on GetOvelappedResult for more information.
           Unlike regular GetOvelappedResult call this parameter can be NULL.
    @param wait[in] If this parameter is 'true', the method does not return
           until the operation has been completed. If this parameter is 'false'
           and the operation is still pending, the method returns 'false' and
           the GetLastError function returns ERROR_IO_INCOMPLETE.
    @return 'true' if I/O has been completed or 'false' on failure or if request
           is not yet completed. If 'false' is returned GetLastError() provides
           extended error information. If GetLastError returns
           ERROR_IO_INCOMPLETE it means that I/O is not yet completed.
  */
  virtual bool GetOvelappedIoResult(LPOVERLAPPED ovl_data,
                                    ULONG* bytes_transferred,
                                    bool wait);

  /** \brief Checks if I/O that this object represents has completed.

    @return 'true' if I/O has been completed or 'false' if it's still
            incomplete. Regardless of the returned value, caller should
            check GetLastError to validate that handle was OK.
  */
  virtual bool IsCompleted();

 public:
  /// Gets overlapped structure for this I/O
  LPOVERLAPPED overlapped() {
    return &overlapped_;
  }

  /// Gets parent object
  AdbIOObject* parent_io_object() const {
    return parent_io_object_;
  }

  /// Gets parent object handle
  ADBAPIHANDLE GetParentObjectHandle() const {
    return (NULL != parent_io_object()) ? parent_io_object()->adb_handle() :
                                          NULL;
  }

  /// Gets address for ADB_IOCTL_BULK_WRITE output buffer
  ULONG* transferred_bytes_ptr() {
    ATLASSERT(is_write_ioctl());
    return &transferred_bytes_;
  }

  /// Gets write IOCTL flag
  bool is_write_ioctl() const {
    return is_write_ioctl_;
  }

  // This is a helper for extracting object from the AdbObjectHandleMap
  static AdbObjectType Type() {
    return AdbObjectTypeIoCompletion;
  }

 protected:
  /// Overlapped structure for this I/O
  OVERLAPPED    overlapped_;

  /// Parent I/O object
  AdbIOObject*  parent_io_object_;

  /// Recepient for number of transferred bytes in write IOCTL
  ULONG         transferred_bytes_;

  /// Expected number of bytes transferred in thi I/O
  ULONG         expected_transfer_size_;

  /// Write IOCTL flag
  bool          is_write_ioctl_;
};

#endif  // ANDROID_USB_API_ADB_IO_COMPLETION_H__