Source to iokit/Families/IOStorage/IOStorage.cpp

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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,
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#include <IOKit/assert.h>
#include <IOKit/IOLib.h>
#include <IOKit/IOSyncer.h>
#include <IOKit/storage/IOStorage.h>

#define super IOService
OSDefineMetaClass(IOStorage, IOService)
OSDefineAbstractStructors(IOStorage, IOService)

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// Local Functions

static void storageCompletion(void *   target,
                              void *   parameter,
                              IOReturn status,
                              UInt64   actualByteCount)
{
    //
    // Internal completion routine for synchronous versions of read and write.
    //

    if (parameter)  *((UInt64 *)parameter) = actualByteCount;
    ((IOSyncer *)target)->signal(status);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

IOReturn IOStorage::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.
    //

    IOStorageCompletion	completion;
    IOSyncer *          completionSyncer;

    // Initialize the lock we will synchronize against.

    completionSyncer = IOSyncer::create();

    // Fill in the completion information for this request.

    completion.target    = completionSyncer;
    completion.action    = storageCompletion;
    completion.parameter = actualByteCount;

    // Issue the asynchronous read.

    read(client, byteStart, buffer, completion);

    // Wait for the read to complete.

    return completionSyncer->wait();
}

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