/* * Copyright (c) 1998-2009 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /*! * @header IOFilterScheme * @abstract * This header contains the IOFilterScheme class definition. */ #ifndef _IOFILTERSCHEME_H #define _IOFILTERSCHEME_H /*! * @defined kIOFilterSchemeClass * @abstract * The name of the IOFilterScheme class. * @discussion * kIOFilterSchemeClass is the name of the IOFilterScheme class. */ #define kIOFilterSchemeClass "IOFilterScheme" #ifdef KERNEL #ifdef __cplusplus /* * Kernel */ #include #include /*! * @class IOFilterScheme * @abstract * The common base class for all filter scheme * objects. * @discussion * The IOFilterScheme class is the common base class for all filter scheme * objects. It extends the IOStorage class by implementing the appropriate * open and close semantics for filter objects (standard semantics are act * as a relay for incoming opens, producing one outgoing open for each * incoming open). It also implements the default read and write semantics, * which pass all reads and writes through to the provider media unprocessed. * For simple schemes, the default behavior is sufficient. More complex * filter schemes such as RAID will want to do extra processing for reads * and writes. */ class IOFilterScheme : public IOStorage { OSDeclareDefaultStructors(IOFilterScheme); protected: struct ExpansionData { /* */ }; ExpansionData * _expansionData; /*! * @function handleOpen * @discussion * The handleOpen method grants or denies permission to access this object * to an interested client. The argument is an IOStorageAccess value that * specifies the level of access desired -- reader or reader-writer. * * This method can be invoked to upgrade or downgrade the access level for * an existing client as well. The previous access level will prevail for * upgrades that fail, of course. A downgrade should never fail. If the * new access level should be the same as the old for a given client, this * method will do nothing and return success. In all cases, one, singular * close-per-client is expected for all opens-per-client received. * * This implementation replaces the IOService definition of handleOpen(). * @param client * Client requesting the open. * @param options * Options for the open. Set to zero. * @param access * Access level for the open. Set to kIOStorageAccessReader or * kIOStorageAccessReaderWriter. * @result * Returns true if the open was successful, false otherwise. */ virtual bool handleOpen(IOService * client, IOOptionBits options, void * access); /*! * @function handleIsOpen * @discussion * The handleIsOpen method determines whether the specified client, or any * client if none is specified, presently has an open on this object. * * This implementation replaces the IOService definition of handleIsOpen(). * @param client * Client to check the open state of. Set to zero to check the open state * of all clients. * @result * Returns true if the client was (or clients were) open, false otherwise. */ virtual bool handleIsOpen(const IOService * client) const; /*! * @function handleClose * @discussion * The handleClose method closes the client's access to this object. * * This implementation replaces the IOService definition of handleClose(). * @param client * Client requesting the close. * @param options * Options for the close. Set to zero. */ virtual void handleClose(IOService * client, IOOptionBits options); public: using IOStorage::read; using IOStorage::write; /*! * @function read * @discussion * Read data from the storage object at the specified byte offset into the * specified buffer, asynchronously. When the read completes, the caller * will be notified via the specified completion action. * * The buffer will be retained for the duration of the read. * * For simple filter schemes, the default behavior is to simply pass the * read through to the provider media. More complex filter schemes such * as RAID will need to do extra processing here. * @param client * Client requesting the read. * @param byteStart * Starting byte offset for the data transfer. * @param buffer * Buffer for the data transfer. The size of the buffer implies the size of * the data transfer. * @param attributes * Attributes of the data transfer. See IOStorageAttributes. It is the * responsibility of the callee to maintain the information for the duration * of the data transfer, as necessary. * @param completion * Completion routine to call once the data transfer is complete. It is the * responsibility of the callee to maintain the information for the duration * of the data transfer, as necessary. */ virtual void read(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, IOStorageAttributes * attributes, IOStorageCompletion * completion); /*! * @function write * @discussion * Write data into the storage object at the specified byte offset from the * specified buffer, asynchronously. When the write completes, the caller * will be notified via the specified completion action. * * The buffer will be retained for the duration of the write. * * For simple filter schemes, the default behavior is to simply pass the * write through to the provider media. More complex filter schemes such * as RAID will need to do extra processing here. * @param client * Client requesting the write. * @param byteStart * Starting byte offset for the data transfer. * @param buffer * Buffer for the data transfer. The size of the buffer implies the size of * the data transfer. * @param attributes * Attributes of the data transfer. See IOStorageAttributes. It is the * responsibility of the callee to maintain the information for the duration * of the data transfer, as necessary. * @param completion * Completion routine to call once the data transfer is complete. It is the * responsibility of the callee to maintain the information for the duration * of the data transfer, as necessary. */ virtual void write(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, IOStorageAttributes * attributes, IOStorageCompletion * completion); /*! * @function synchronizeCache * @discussion * Flush the cached data in the storage object, if any, synchronously. * @param client * Client requesting the cache synchronization. * @result * Returns the status of the cache synchronization. */ virtual IOReturn synchronizeCache(IOService * client); /*! * @function discard * @discussion * Delete unused data from the storage object at the specified byte offset, * synchronously. * @param client * Client requesting the operation. * @param byteStart * Starting byte offset for the operation. * @param byteCount * Size of the operation. * @result * Returns the status of the operation. */ virtual IOReturn discard(IOService * client, UInt64 byteStart, UInt64 byteCount); /* * Obtain this object's provider. We override the superclass's method * to return a more specific subclass of OSObject -- an IOMedia. This * method serves simply as a convenience to subclass developers. */ virtual IOMedia * getProvider() const; OSMetaClassDeclareReservedUnused(IOFilterScheme, 0); OSMetaClassDeclareReservedUnused(IOFilterScheme, 1); OSMetaClassDeclareReservedUnused(IOFilterScheme, 2); OSMetaClassDeclareReservedUnused(IOFilterScheme, 3); OSMetaClassDeclareReservedUnused(IOFilterScheme, 4); OSMetaClassDeclareReservedUnused(IOFilterScheme, 5); OSMetaClassDeclareReservedUnused(IOFilterScheme, 6); OSMetaClassDeclareReservedUnused(IOFilterScheme, 7); OSMetaClassDeclareReservedUnused(IOFilterScheme, 8); OSMetaClassDeclareReservedUnused(IOFilterScheme, 9); OSMetaClassDeclareReservedUnused(IOFilterScheme, 10); OSMetaClassDeclareReservedUnused(IOFilterScheme, 11); OSMetaClassDeclareReservedUnused(IOFilterScheme, 12); OSMetaClassDeclareReservedUnused(IOFilterScheme, 13); OSMetaClassDeclareReservedUnused(IOFilterScheme, 14); OSMetaClassDeclareReservedUnused(IOFilterScheme, 15); OSMetaClassDeclareReservedUnused(IOFilterScheme, 16); OSMetaClassDeclareReservedUnused(IOFilterScheme, 17); OSMetaClassDeclareReservedUnused(IOFilterScheme, 18); OSMetaClassDeclareReservedUnused(IOFilterScheme, 19); OSMetaClassDeclareReservedUnused(IOFilterScheme, 20); OSMetaClassDeclareReservedUnused(IOFilterScheme, 21); OSMetaClassDeclareReservedUnused(IOFilterScheme, 22); OSMetaClassDeclareReservedUnused(IOFilterScheme, 23); OSMetaClassDeclareReservedUnused(IOFilterScheme, 24); OSMetaClassDeclareReservedUnused(IOFilterScheme, 25); OSMetaClassDeclareReservedUnused(IOFilterScheme, 26); OSMetaClassDeclareReservedUnused(IOFilterScheme, 27); OSMetaClassDeclareReservedUnused(IOFilterScheme, 28); OSMetaClassDeclareReservedUnused(IOFilterScheme, 29); OSMetaClassDeclareReservedUnused(IOFilterScheme, 30); OSMetaClassDeclareReservedUnused(IOFilterScheme, 31); }; #endif /* __cplusplus */ #endif /* KERNEL */ #endif /* !_IOFILTERSCHEME_H */