protected:
inline void complete(IOStorageCompletion completion, IOReturn status, UInt64 actualByteCount = 0);
Invokes the specified completion action of the read/write request. If the completion action is unspecified, no action is taken. This method serves simply as a convenience to storage subclass developers.
Name Description completion Completion information for the data transfer. status Status of the data transfer. actualByteCount Actual number of bytes transferred in the data transfer.
protected:
virtual void handleClose(IOService * client, IOOptionBits options) = 0;
The handleClose method closes the client's access to this object.
Name Description client Client requesting the close. options Options for the close. Set to zero.
protected:
virtual bool handleIsOpen(const IOService * client) const = 0;
The handleIsOpen method determines whether the specified client, or any client if none is specificed, presently has an open on this object.
Result: Returns true if the client was (or clients were) open, false otherwise.
Name Description client Client to check the open state of. Set to zero to check the open state of all clients.
protected:
virtual bool handleOpen(IOService * client, IOOptionBits options, void * access) = 0;
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.
Result: Returns true if the open was successful, false otherwise.
Name Description client Client requesting the open. options Options for the open. Set to zero. access Access level for the open. Set to kAccessReader or kAccessReaderWriter.
public:
inline bool open(IOService * client, IOOptionBits options, IOStorageAccess access);
Ask the storage object for permission to access its contents; the method is equivalent to IOService::open(), but with the correct parameter types. * This method may also be invoked to upgrade or downgrade the access of an existing open (if it fails, the existing open prevails).
Result: Returns true if the open was successful, false otherwise.
Name Description client Client requesting the open. options Options for the open. Set to zero. access Access level for the open. Set to kAccessReader or kAccessReaderWriter.
public:
virtual void read(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, IOStorageCompletion completion) = 0;
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.
Name Description client Client requesting the read. byteStart Starting byte offset for the data transfer. buffer Buffer for the data transfer. The size of the buffer implies the size of the data transfer. completion Completion routine to call once the data transfer is complete.
public:
virtual IOReturn read(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, UInt64 * actualByteCount = 0);
Read data from the storage object at the specified byte offset into the specified buffer, synchronously. When the read completes, this method will return to the caller. The actual byte count field is optional.
Result: Returns the status of the data transfer.
Name Description client Client requesting the read. byteStart Starting byte offset for the data transfer. buffer Buffer for the data transfer. The size of the buffer implies the size of the data transfer. actualByteCount Returns the actual number of bytes transferred in the data transfer.
public:
virtual void write(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, IOStorageCompletion completion) = 0;
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.
Name Description client Client requesting the write. byteStart Starting byte offset for the data transfer. buffer Buffer for the data transfer. The size of the buffer implies the size of the data transfer. completion Completion routine to call once the data transfer is complete.
public:
virtual IOReturn write(IOService * client, UInt64 byteStart, IOMemoryDescriptor * buffer, UInt64 * actualByteCount = 0);
Write data into the storage object at the specified byte offset from the specified buffer, synchronously. When the write completes, this method will return to the caller. The actual byte count field is optional.
Result: Returns the status of the data transfer.
Name Description client Client requesting the write. byteStart Starting byte offset for the data transfer. buffer Buffer for the data transfer. The size of the buffer implies the size of the data transfer. actualByteCount Returns the actual number of bytes transferred in the data transfer.
© 2000 Apple Computer, Inc. (Last Updated 2/23/2000)