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_ */ 84