iokit/IOKit/IOCommand.h

   1 /*
   2  * Copyright (c) 2019 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*
  30  *
  31  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  32  *
  33  *      HISTORY
  34  *
  35  *      2001-01-18 gvdl Made the primary queue pointer public, to be used when
  36  *                      Ownership is clear.
  37  *      11/13/2000 CJS  Created IOCommand class and implementation
  38  *
  39  */
  40
  41 /*!
  42  * @header IOCommand
  43  * @abstract
  44  * This header contains the IOCommand class definition.
  45  */
  46
  47 #ifndef _IOKIT_IO_COMMAND_H_
  48 #define _IOKIT_IO_COMMAND_H_
  49
  50 /*
  51  * Kernel
  52  */
  53
  54 #if defined(KERNEL) && defined(__cplusplus)
  55
  56 #include <kern/queue.h>
  57 #include <libkern/c++/OSObject.h>
  58
  59 /*!
  60  * @class IOCommand
  61  * @abstract
  62  * This class is an abstract class which represents an I/O command.
  63  * @discussion
  64  * This class is an abstract class which represents an I/O command passed
  65  * from a device driver to a controller. All controller commands (e.g. IOATACommand)
  66  * should inherit from this class.
  67  */
  68
  69 class IOCommand : public OSObject
  70 {
  71         OSDeclareDefaultStructors(IOCommand);
  72
  73 public:
  74         virtual bool init(void) APPLE_KEXT_OVERRIDE;
  75
  76 /*! @var fCommandChain
  77  *   This variable is used by the current 'owner' to queue the command.  During the life cycle of a command it moves through a series of queues.  This is the queue pointer for it.  Only valid while 'ownership' is clear.  For instance a IOCommandPool uses this pointer to maintain its list of free commands.  May be manipulated using the kern/queue.h macros */
  78         queue_chain_t fCommandChain;    /* used to queue commands */
  79 };
  80
  81 #endif /* defined(KERNEL) && defined(__cplusplus) */
  82
  83 #endif  /* _IOKIT_IO_COMMAND_H_ */