iokit/IOKit/IORegistryEntry.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
  25  *
  26  * HISTORY
  27  *
  28  */
  29
  30
  31 #ifndef _IOKIT_IOREGISTRYENTRY_H
  32 #define _IOKIT_IOREGISTRYENTRY_H
  33
  34 #include <IOKit/IOTypes.h>
  35 #include <libkern/c++/OSContainers.h>
  36
  37
  38 extern const OSSymbol * gIONameKey;
  39 extern const OSSymbol * gIOLocationKey;
  40
  41 class IORegistryEntry;
  42 class IORegistryPlane;
  43 class IORegistryIterator;
  44
  45 typedef void (*IORegistryEntryApplierFunction)(IORegistryEntry * entry,
  46                                                void * context);
  47
  48 enum {
  49     kIORegistryIterateRecursively       = 0x00000001,
  50     kIORegistryIterateParents           = 0x00000002
  51 };
  52
  53 /*! @class IORegistryEntry : public OSObject
  54     @abstract The base class for all objects in the registry.
  55     @discussion The IORegistryEntry base class provides functions for describing graphs of connected registry entries, each with a dictionary-based property table. Entries may be connected in different planes, with differing topologies. Access to the registry is protected against multiple threads. Inside the kernel planes are specified with plane objects and are published by the creator - IOService exports the gIOServicePlane plane object for example. Non kernel clients specify planes by their name.
  56 */
  57
  58 class IORegistryEntry : public OSObject
  59 {
  60     friend class IORegistryIterator;
  61
  62     OSDeclareDefaultStructors(IORegistryEntry)
  63
  64 protected:
  65 /*! @struct ExpansionData
  66     @discussion This structure will be used to expand the capablilties of this class in the future.
  67     */
  68     struct ExpansionData { };
  69
  70 /*! @var reserved
  71     Reserved for future use.  (Internal use only)  */
  72     ExpansionData * reserved;
  73
  74 private:
  75
  76     OSDictionary *      fRegistryTable;
  77     OSDictionary *      fPropertyTable;
  78
  79 public:
  80     /* methods available in Mac OS X 10.1 or later */
  81
  82 /*! @function copyProperty
  83     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy. Available in Mac OS X 10.1 or later.
  84     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
  85     @param aKey The property's name as a C-string.
  86     @param plane The plane to iterate over, eg. gIOServicePlane.
  87     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
  88     @result The property value found, or zero. A reference on any found property is returned to caller, which should be released. */
  89
  90     virtual OSObject * copyProperty( const char *           aKey,
  91                                      const IORegistryPlane * plane,
  92                                      IOOptionBits            options =
  93                                         kIORegistryIterateRecursively |
  94                                         kIORegistryIterateParents) const;
  95     OSMetaClassDeclareReservedUsed(IORegistryEntry, 0);
  96
  97 /*! @function copyProperty
  98     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy. Available in Mac OS X 10.1 or later.
  99     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
 100     @param aKey The property's name as an OSString.
 101     @param plane The plane to iterate over, eg. gIOServicePlane.
 102     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
 103     @result The property value found, or zero. A reference on any found property is returned to caller, which should be released. */
 104
 105     virtual OSObject * copyProperty( const OSString *        aKey,
 106                                      const IORegistryPlane * plane,
 107                                      IOOptionBits            options =
 108                                         kIORegistryIterateRecursively |
 109                                         kIORegistryIterateParents) const;
 110     OSMetaClassDeclareReservedUsed(IORegistryEntry, 1);
 111
 112 /*! @function copyProperty
 113     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy. Available in Mac OS X 10.1 or later.
 114     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
 115     @param aKey The property's name as an OSSymbol.
 116     @param plane The plane to iterate over, eg. gIOServicePlane.
 117     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
 118     @result The property value found, or zero. A reference on any found property is returned to caller, which should be released. */
 119
 120     virtual OSObject * copyProperty( const OSSymbol *        aKey,
 121                                      const IORegistryPlane * plane,
 122                                      IOOptionBits            options =
 123                                         kIORegistryIterateRecursively |
 124                                         kIORegistryIterateParents) const;
 125     OSMetaClassDeclareReservedUsed(IORegistryEntry, 2);
 126
 127 /*! @function copyParentEntry
 128     @abstract Returns an registry entry's first parent entry in a plane. Available in Mac OS X 10.1 or later.
 129     @discussion This function will return the parent to which a registry entry was first attached. Since the majority of registry entrys have only one provider, this is a useful simplification.
 130     @param plane The plane object.
 131     @result Returns the first parent of the registry entry, or zero if the entry is not attached into the registry in that plane. A reference on the entry is returned to caller, which should be released. */
 132
 133     virtual IORegistryEntry * copyParentEntry( const IORegistryPlane * plane ) const;
 134     OSMetaClassDeclareReservedUsed(IORegistryEntry, 3);
 135
 136 /*! @function copyChildEntry
 137     @abstract Returns an registry entry's first child entry in a plane. Available in Mac OS X 10.1 or later.
 138     @discussion This function will return the child which first attached to a registry entry.
 139     @param plane The plane object.
 140     @result Returns the first child of the registry entry, or zero if the entry is not attached into the registry in that plane. A reference on the entry is returned to caller, which should be released. */
 141
 142     virtual IORegistryEntry * copyChildEntry( const IORegistryPlane * plane ) const;
 143     OSMetaClassDeclareReservedUsed(IORegistryEntry, 4);
 144
 145     /* method available in Mac OS X 10.4 or later */
 146 /*!
 147     @typedef Action
 148     @discussion Type and arguments of callout C function that is used when
 149 a runCommand is executed by a client.  Cast to this type when you want a C++
 150 member function to be used.  Note the arg1 - arg3 parameters are passed straight pass through to the action callout.
 151     @param target
 152         Target of the function, can be used as a refcon.  Note if a C++ function
 153 was specified, this parameter is implicitly the first parameter in the target
 154 member function's parameter list.
 155     @param arg0 Argument to action from run operation.
 156     @param arg1 Argument to action from run operation.
 157     @param arg2 Argument to action from run operation.
 158     @param arg3 Argument to action from run operation.
 159 */
 160     typedef IOReturn (*Action)(OSObject *target,
 161                                void *arg0, void *arg1,
 162                                void *arg2, void *arg3);
 163
 164 /*! @function runPropertyAction
 165     @abstract Single thread a call to an action w.r.t. the property lock
 166     @discussion Client function that causes the given action to be called in a manner that syncrhonises with the registry iterators and serialisers.  This functin can be used to synchronously manipulate the property table of this nub
 167     @param action Pointer to function to be executed in work-loop context.
 168     @param arg0 Parameter for action parameter, defaults to 0.
 169     @param arg1 Parameter for action parameter, defaults to 0.
 170     @param arg2 Parameter for action parameter, defaults to 0.
 171     @param arg3 Parameter for action parameter, defaults to 0.
 172     @result Returns the value of the Action callout.
 173 */
 174     virtual IOReturn runPropertyAction(Action action, OSObject *target,
 175                                void *arg0 = 0, void *arg1 = 0,
 176                                void *arg2 = 0, void *arg3 = 0);
 177     OSMetaClassDeclareReservedUsed(IORegistryEntry, 5);
 178
 179 private:
 180
 181     OSMetaClassDeclareReservedUnused(IORegistryEntry, 6);
 182     OSMetaClassDeclareReservedUnused(IORegistryEntry, 7);
 183     OSMetaClassDeclareReservedUnused(IORegistryEntry, 8);
 184     OSMetaClassDeclareReservedUnused(IORegistryEntry, 9);
 185     OSMetaClassDeclareReservedUnused(IORegistryEntry, 10);
 186     OSMetaClassDeclareReservedUnused(IORegistryEntry, 11);
 187     OSMetaClassDeclareReservedUnused(IORegistryEntry, 12);
 188     OSMetaClassDeclareReservedUnused(IORegistryEntry, 13);
 189     OSMetaClassDeclareReservedUnused(IORegistryEntry, 14);
 190     OSMetaClassDeclareReservedUnused(IORegistryEntry, 15);
 191     OSMetaClassDeclareReservedUnused(IORegistryEntry, 16);
 192     OSMetaClassDeclareReservedUnused(IORegistryEntry, 17);
 193     OSMetaClassDeclareReservedUnused(IORegistryEntry, 18);
 194     OSMetaClassDeclareReservedUnused(IORegistryEntry, 19);
 195     OSMetaClassDeclareReservedUnused(IORegistryEntry, 20);
 196     OSMetaClassDeclareReservedUnused(IORegistryEntry, 21);
 197     OSMetaClassDeclareReservedUnused(IORegistryEntry, 22);
 198     OSMetaClassDeclareReservedUnused(IORegistryEntry, 23);
 199     OSMetaClassDeclareReservedUnused(IORegistryEntry, 24);
 200     OSMetaClassDeclareReservedUnused(IORegistryEntry, 25);
 201     OSMetaClassDeclareReservedUnused(IORegistryEntry, 26);
 202     OSMetaClassDeclareReservedUnused(IORegistryEntry, 27);
 203     OSMetaClassDeclareReservedUnused(IORegistryEntry, 28);
 204     OSMetaClassDeclareReservedUnused(IORegistryEntry, 29);
 205     OSMetaClassDeclareReservedUnused(IORegistryEntry, 30);
 206     OSMetaClassDeclareReservedUnused(IORegistryEntry, 31);
 207
 208 public:
 209
 210     /* Registry accessors */
 211
 212 /*! @function getRegistryRoot
 213     @abstract Returns a pointer to the root instance of the registry.
 214     @discussion This method provides an accessor to the root of the registry for the machine. The root may be passed to a registry iterator when iterating a plane, and contains properties that describe the available planes, and diagnostic information for IOKit. Keys for these properties are in IOKitKeys.h.
 215     @result A pointer to the IORegistryEntry root instance. It should not be released by the caller. */
 216
 217     static IORegistryEntry * getRegistryRoot( void );
 218
 219 /*! @function getGenerationCount
 220     @abstract Returns an generation count for all registry changing operations.
 221     @discussion This method provides an accessor to the current generation count (or seed) of the registry which changes when any topology change occurs in the registry - this does not include property table changes. It may be used to invalidate any caching of the results from IORegistryEntry methods.
 222     @result An integer generation count. */
 223
 224     static SInt32            getGenerationCount( void );
 225
 226 /*! @function getPlane
 227     @abstract Looks up the plane object by a C-string name.
 228     @discussion Planes are usually provided as globals by the creator, eg. gIOServicePlane, gIODeviceTreePlane, or gIOAudioPlane, however they may also be looked up by name with this method.
 229     @result A pointer to the plane object, or zero if no such plane exists. The returned plane should not be released. */
 230
 231     static const IORegistryPlane * getPlane( const char * name );
 232
 233     /* Registry Entry allocation & init */
 234
 235 /*! @function init
 236     @abstract Standard init method for all IORegistryEntry subclasses.
 237     @discussion A registry entry must be initialized with this method before it can be used. A property dictionary may passed and will be retained by this method for use as the registry entry's property table, or an empty one will be created.
 238     @param A dictionary that will become the registry entry's property table (retaining it), or zero which will cause an empty property table to be created.
 239     @result true on success, or false on a resource failure. */
 240
 241     virtual bool init( OSDictionary * dictionary = 0 );
 242
 243 /*! @function free
 244     @abstract Standard free method for all IORegistryEntry subclasses.
 245     @discussion This method will release any resources of the entry, in particular its property table. Note that the registry entry must always be detached from the registry before free may be called, and subclasses (namely IOService) will have additional protocols for removing registry entries. free should never need be called directly. */
 246
 247     virtual void free( void );
 248
 249 /*! @function setPropertyTable
 250     @abstract Replace a registry entry's property table.
 251     @discussion This method will release the current property table of a the entry and replace it with another, retaining the new property table.
 252     @param dict The new dictionary to be used as the entry's property table. */
 253
 254     virtual void setPropertyTable( OSDictionary * dict );
 255
 256     /* Synchronized property accessors; wrappers to OSDictionary
 257      * plus property creation helpers */
 258
 259 /*! @function setProperty
 260     @abstract Synchronized method to add a property to a registry entry's property table.
 261     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 262     @param aKey The properties name as an OSSymbol.
 263     @param anObject The property value.
 264     @result true on success or false on a resource failure. */
 265
 266     virtual bool setProperty(const OSSymbol * aKey, OSObject * anObject);
 267
 268 /*! @function setProperty
 269     @abstract Synchronized method to add a property to a registry entry's property table.
 270     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 271     @param aKey The property's name as an OSString.
 272     @param anObject The property value.
 273     @result true on success or false on a resource failure. */
 274
 275     virtual bool setProperty(const OSString * aKey, OSObject * anObject);
 276
 277 /*! @function setProperty
 278     @abstract Synchronized method to add a property to a registry entry's property table.
 279     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 280     @param aKey The property's name as a C-string.
 281     @param anObject The property value.
 282     @result true on success or false on a resource failure. */
 283
 284     virtual bool setProperty(const char * aKey, OSObject * anObject);
 285
 286 /*! @function setProperty
 287     @abstract Synchronized method to construct and add a OSString property to a registry entry's property table.
 288     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table. The property is created as an OSString from the supplied C-string, set in the property table with the given name, and released.
 289     @param aKey The property's name as a C-string.
 290     @param aString The property value as a C-string.
 291     @result true on success or false on a resource failure. */
 292
 293     virtual bool setProperty(const char * aKey, const char * aString);
 294
 295 /*! @function setProperty
 296     @abstract Synchronized method to construct and add an OSBoolean property to a registry entry's property table.
 297     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table. The property is created as an OSBoolean from the supplied value, set in the property table with the given name, and released.
 298     @param aKey The property's name as a C-string.
 299     @param aBoolean The property's boolean value.
 300     @result true on success or false on a resource failure. */
 301
 302     virtual bool setProperty(const char * aKey, bool aBoolean);
 303
 304 /*! @function setProperty
 305     @abstract Synchronized method to construct and add an OSNumber property to a registry entry's property table.
 306     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table. The property is created as an OSNumber from the supplied value and size, set in the property table with the given name, and released.
 307     @param aKey The property's name as a C-string.
 308     @param aValue The property's numeric value.
 309     @param aNumberOfBits The property's size in bits, for OSNumber.
 310     @result true on success or false on a resource failure. */
 311
 312     virtual bool setProperty( const char *       aKey,
 313                               unsigned long long aValue,
 314                               unsigned int       aNumberOfBits);
 315
 316 /*! @function setProperty
 317     @abstract Synchronized method to construct and add an OSData property to a registry entry's property table.
 318     @discussion This method will add or replace a property in a registry entry's property table, using the OSDictionary::setObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table. The property is created as an OSData copied from the supplied date and length, set in the property table with the given name, and released.
 319     @param aKey The property's name as a C-string.
 320     @param bytes The property's value as a pointer. OSData will copy this data.
 321     @param length The property's size in bytes, for OSData.
 322     @result true on success or false on a resource failure. */
 323
 324     virtual bool setProperty( const char *       aKey,
 325                               void *             bytes,
 326                               unsigned int       length);
 327
 328 /*! @function removeProperty
 329     @abstract Synchronized method to remove a property from a registry entry's property table.
 330     @discussion This method will remove a property from a registry entry's property table, using the OSDictionary::removeObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 331     @param aKey The property's name as an OSSymbol. */
 332
 333     virtual void removeProperty( const OSSymbol * aKey);
 334
 335 /*! @function removeProperty
 336     @abstract Synchronized method to remove a property from a registry entry's property table.
 337     @discussion This method will remove a property from a registry entry's property table, using the OSDictionary::removeObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 338     @param aKey The property's name as an OSString. */
 339
 340     virtual void removeProperty( const OSString * aKey);
 341
 342 /*! @function removeProperty
 343     @abstract Synchronized method to remove a property from a registry entry's property table.
 344     @discussion This method will remove a property from a registry entry's property table, using the OSDictionary::removeObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 345     @param aKey The property's name as a C-string. */
 346
 347     virtual void removeProperty( const char * aKey);
 348
 349 /*! @function getProperty
 350     @abstract Synchronized method to obtain a property from a registry entry's property table.
 351     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 352     @param aKey The property's name as an OSSymbol.
 353     @result The property value found, or zero. */
 354
 355     virtual OSObject * getProperty( const OSSymbol * aKey) const;
 356
 357 /*! @function getProperty
 358     @abstract Synchronized method to obtain a property from a registry entry's property table.
 359     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 360     @param aKey The property's name as an OSString.
 361     @result The property value found, or zero. */
 362
 363     virtual OSObject * getProperty( const OSString * aKey) const;
 364
 365 /*! @function getProperty
 366     @abstract Synchronized method to obtain a property from a registry entry's property table.
 367     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics. This method is synchronized with other IORegistryEntry accesses to the property table.
 368     @param aKey The property's name as a C-string.
 369     @result The property value found, or zero. */
 370
 371     virtual OSObject * getProperty( const char * aKey) const;
 372
 373 /*! @function getProperty
 374     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy.
 375     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
 376     @param aKey The property's name as an OSSymbol.
 377     @param plane The plane to iterate over, eg. gIOServicePlane.
 378     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
 379     @result The property value found, or zero. */
 380
 381     virtual OSObject * getProperty( const OSSymbol *        aKey,
 382                                     const IORegistryPlane * plane,
 383                                     IOOptionBits            options =
 384                                         kIORegistryIterateRecursively |
 385                                         kIORegistryIterateParents) const;
 386
 387 /*! @function getProperty
 388     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy.
 389     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
 390     @param aKey The property's name as an OSString.
 391     @param plane The plane to iterate over, eg. gIOServicePlane.
 392     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
 393     @result The property value found, or zero. */
 394
 395     virtual OSObject * getProperty( const OSString *        aKey,
 396                                     const IORegistryPlane * plane,
 397                                     IOOptionBits            options =
 398                                         kIORegistryIterateRecursively |
 399                                         kIORegistryIterateParents) const;
 400
 401 /*! @function getProperty
 402     @abstract Synchronized method to obtain a property from a registry entry or one of its parents (or children) in the hierarchy.
 403     @discussion This method will search for a property, starting first with this registry entry's property table, then iterating recusively through either the parent registry entries or the child registry entries of this entry. Once the first occurrence is found, it will lookup and return the value of the property, using the OSDictionary::getObject semantics. The iteration keeps track of entries that have been recursed into previously to avoid loops. This method is synchronized with other IORegistryEntry accesses to the property table(s).
 404     @param aKey The property's name as a C-string.
 405     @param plane The plane to iterate over, eg. gIOServicePlane.
 406     @param options kIORegistryIterateRecursively may be set to recurse automatically into the registry hierarchy. Without this option, this method degenerates into the standard getProperty() call. kIORegistryIterateParents may be set to iterate the parents of the entry, in place of the children.
 407     @result The property value found, or zero. */
 408
 409     virtual OSObject * getProperty( const char *            aKey,
 410                                     const IORegistryPlane * plane,
 411                                     IOOptionBits            options =
 412                                         kIORegistryIterateRecursively |
 413                                         kIORegistryIterateParents) const;
 414
 415 /*! @function copyProperty
 416     @abstract Synchronized method to obtain a property from a registry entry's property table.
 417     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics, and return a reference to the caller. This method is synchronized with other IORegistryEntry accesses to the property table.
 418     @param aKey The property's name as an OSSymbol.
 419     @result The property value found, or zero. It should be released by the caller. */
 420
 421     virtual OSObject * copyProperty( const OSSymbol * aKey) const;
 422
 423 /*! @function copyProperty
 424     @abstract Synchronized method to obtain a property from a registry entry's property table.
 425     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics, and return a reference to the caller. This method is synchronized with other IORegistryEntry accesses to the property table.
 426     @param aKey The property's name as an OSString.
 427     @result The property value found, or zero. It should be released by the caller. */
 428
 429     virtual OSObject * copyProperty( const OSString * aKey) const;
 430
 431 /*! @function copyProperty
 432     @abstract Synchronized method to obtain a property from a registry entry's property table.
 433     @discussion This method will lookup a property in a registry entry's property table, using the OSDictionary::getObject semantics, and return a reference to the caller. This method is synchronized with other IORegistryEntry accesses to the property table.
 434     @param aKey The property's name as a C-string.
 435     @result The property value found, or zero. It should be released by the caller. */
 436
 437     virtual OSObject * copyProperty( const char * aKey) const;
 438
 439 /*! @function dictionaryWithProperties
 440     @abstract Synchronized method to obtain copy a registry entry's property table.
 441     @discussion This method will copy a registry entry's property table, using the OSDictionary::withDictionary semantics. This method is synchronized with other IORegistryEntry accesses to the property table. Since OSDictionary will only copy property values by reference, synchronization is not guaranteed to any collection values.
 442     @result The created dictionary, or zero on a resource value. It should be released by the caller. */
 443
 444     virtual OSDictionary * dictionaryWithProperties( void ) const;
 445
 446 /*! @function serializeProperties
 447     @abstract Synchronized method to serialize a registry entry's property table.
 448     @discussion This method will serialize a registry entry's property table, using the OSDictionary::serialize semantics. This method is synchronized with other IORegistryEntry accesses to the property table. Many non-kernel clients of IOKit read information from the registry via properties, and will invoke this method in a registry entry to create a serialization of all the entry's properties, which is then reconstructed in the client's task as a CFDictionary. This method may be intercepted by subclasses to update their properties or implement a different serialization method, though it is usually better to implement such functionality by creating objects in the property table and implementing their serialize methods, avoiding any need to implement serializeProperties.
 449     @param serialize The OSSerialize instance representing the serialization request.
 450     @result True on success, false otherwise. */
 451
 452     virtual bool serializeProperties( OSSerialize * serialize ) const;
 453
 454     /* Unsynchronized(!) property table access */
 455
 456 /*! @function getPropertyTable
 457     @abstract Unsynchronized accessor to a registry entry's property table.
 458     @discussion This method will return a pointer to the live property table as an OSDictionery. Its use is not recommended in most cases, instead use the synchronized accessors and helper functions of IORegistryEntry to access properties. It can only safely be used by one thread, which usually means it can only be used before a registry entry is entered into the registry.
 459     @result A pointer to the property table as an OSDictionary. The pointer is valid while the registry entry is retained, and should not be released by the caller. */
 460
 461     /* inline */ OSDictionary * getPropertyTable( void ) const;
 462             /* { return(fPropertyTable); } */
 463
 464     /* Set properties from user level, to be overridden if supported */
 465
 466 /*! @function setProperties
 467     @abstract Optionally supported external method to set properties in a registry entry.
 468     @discussion This method is not implemented by IORegistryEntry, but is available to kernel and non-kernel clients to set properties in a registry entry. IOUserClient provides connection based, more controlled access to this functionality and may be more appropriate for many uses, since there is no differentiation between clients available to this method.
 469     @param properties Any OSObject subclass, to be interpreted by the implementing method - for example an OSDictionary, OSData etc. may all be appropriate.
 470     @result An IOReturn code to be returned to the caller. */
 471
 472     virtual IOReturn setProperties( OSObject * properties );
 473
 474     /* Topology */
 475
 476 /*! @function getParentIterator
 477     @abstract Returns an iterator over an registry entry's parent entries in a specified plane.
 478     @param plane The plane object.
 479     @result Returns an iterator over the parents of the registry entry, or zero if there is a resource failure. The iterator must be released when the iteration is finished. All objects returned by the iteration are retained while the iterator is valid, though they may no longer be attached during the iteration. */
 480
 481     virtual OSIterator * getParentIterator( const IORegistryPlane * plane )
 482                                                                         const;
 483     virtual void applyToParents( IORegistryEntryApplierFunction applier,
 484                                  void * context,
 485                                  const IORegistryPlane * plane ) const;
 486
 487 /*! @function getParentEntry
 488     @abstract Returns an registry entry's first parent entry in a plane.
 489     @discussion This function will return the parent to which a registry entry was first attached. Since the majority of registry entrys have only one provider, this is a useful simplification.
 490     @param plane The plane object.
 491     @result Returns the first parent of the registry entry, or zero if the entry is not attached into the registry in that plane. The parent is retained while the entry is attached, and should not be released by the caller. */
 492
 493     virtual IORegistryEntry * getParentEntry( const IORegistryPlane * plane ) const;
 494
 495 /*! @function getChildIterator
 496     @abstract Returns an iterator over an registry entry's child entries in a plane.
 497     @discussion This method creates an iterator which will return each of a registry entry's child entries in a specified plane.
 498     @param plane The plane object.
 499     @result Returns an iterator over the children of the entry, or zero if there is a resource failure. The iterator must be released when the iteration is finished. All objects returned by the iteration are retained while the iterator is valid, though they may no longer be attached during the iteration. */
 500
 501     virtual OSIterator * getChildIterator( const IORegistryPlane * plane )
 502                                                                         const;
 503
 504     virtual void applyToChildren( IORegistryEntryApplierFunction applier,
 505                                   void * context,
 506                                   const IORegistryPlane * plane ) const;
 507
 508 /*! @function getChildEntry
 509     @abstract Returns an registry entry's first child entry in a plane.
 510     @discussion This function will return the child which first attached to a registry entry.
 511     @param plane The plane object.
 512     @result Returns the first child of the registry entry, or zero if the entry is not attached into the registry in that plane. The child is retained while the entry is attached, and should not be released by the caller. */
 513
 514     virtual IORegistryEntry * getChildEntry( const IORegistryPlane * plane ) const;
 515
 516 /*! @function isChild
 517     @abstract Determines whether a registry entry is the child of another in a plane.
 518     @discussion This method called in the parent entry determines if the specified entry is a child, in a plane. Additionally, it can check if the child is the only child of the parent entry.
 519     @param child The possible child registry entry.
 520     @param plane The plane object.
 521     @param onlyChild If true, check also if the child is the only child.
 522     @result If the child argument is not a child of the registry entry, false is returned. If onlyChild is true and the child is not the only child of the entry, false is returned, otherwise true is returned. */
 523
 524     virtual bool isChild( IORegistryEntry * child,
 525                                 const IORegistryPlane * plane,
 526                                 bool onlyChild = false ) const;
 527
 528 /*! @function isParent
 529     @abstract Determines whether a registry entry is the parent of another in a plane.
 530     @discussion This method called in the child entry determines if the specified entry is a parent, in a plane. Additionally, it can check if the parent is the only parent of the child entry.
 531     @param parent The possible parent registry entry.
 532     @param plane The plane object.
 533     @param onlyParent If true, check also if the parent is the only parent.
 534     @result If the parent argument is not a parent of the registry entry, false is returned. If onlyParent is true and the parent is not the only parent of the entry, false is returned, otherwise true is returned. */
 535
 536     virtual bool isParent( IORegistryEntry * parent,
 537                                 const IORegistryPlane * plane,
 538                                 bool onlyParent = false ) const;
 539
 540 /*! @function inPlane
 541     @abstract Determines whether a registry entry is attached in a plane.
 542     @discussion This method determines if the entry is attached in a plane to any other entry.  It can also be used to determine if the entry is a member of any plane.
 543     @param plane The plane object, 0 indicates any plane.
 544     @result If the entry has a parent in the given plane or if plane = 0 then if entry has any parent; return true, otherwise false. */
 545
 546     virtual bool inPlane( const IORegistryPlane * plane = 0) const;
 547
 548 /*! @function getDepth
 549     @abstract Counts the maximum number of entries between an entry and the registry root, in a plane.
 550     @discussion This method counts the number of entries between and entry and the registry root, in a plane, for each parent of the entry and returns the maximum value.
 551     @param plane The plane object.
 552     @result The maximum number of entries between the entry and the root. Zero is returned if the entry is not attached in the plane. */
 553
 554     virtual unsigned int getDepth( const IORegistryPlane * plane ) const;
 555
 556     /* Attach / detach */
 557
 558 /*! @function attachToParent
 559     @abstract Attaches a entry to a parent entry in a plane.
 560     @discussion This is the usual method of entering an entry into the registry. It is a no-op and success if the entry is already attached to the parent. Attaching the  entry into the registry retains both the child and parent while they are attached. This method will call attachToChild in the parent entry if it is not being called from attachToChild.
 561     @param parent The registry entry to attach to.
 562     @param plane The plane object.
 563     @result true on success, or false on a resource failure, or if the parent is the same as the child. */
 564
 565     virtual bool attachToParent( IORegistryEntry * parent,
 566                                 const IORegistryPlane * plane );
 567
 568 /*! @function detachFromParent
 569     @abstract Detaches an entry from a parent entry in a plane.
 570     @discussion This is the usual method of removing an entry from the registry. It is a no-op if the entry is not attached to the parent. Detaching the entry will release both the child and parent. This method will call detachFromChild in the parent entry if it is not being called from detachFromChild.
 571     @param parent The registry entry to detach from.
 572     @param plane The plane object. */
 573
 574     virtual void detachFromParent( IORegistryEntry * parent,
 575                                 const IORegistryPlane * plane );
 576
 577 /*! @function attachToChild
 578     @abstract Method called in the parent entry when a child attaches.
 579     @discussion This method is called in the parent entry when a child attaches, to make overrides possible. This method will also call attachToParent in the child entry if it is not being called from attachToParent. It is a no-op and success if the entry is already a child. Attaching the  entry into the registry retains both the child and parent while they are attached.
 580     @param child The registry entry being attached.
 581     @param plane The plane object.
 582     @result true on success, or false on a resource failure, or if the parent is the same as the child. */
 583
 584     virtual bool attachToChild( IORegistryEntry * child,
 585                                 const IORegistryPlane * plane );
 586
 587 /*! @function detachFromChild
 588     @abstract Detaches a child entry from its parent in a plane.
 589     @discussion This method is called in the parent entry when a child detaches, to make overrides possible. It is a no-op if the entry is not a child of the parent. Detaching the entry will release both the child and parent. This method will call detachFromParent in the child entry if it is not being called from detachFromParent.
 590     @param parent The registry entry to detach.
 591     @param plane The plane object. */
 592
 593     virtual void detachFromChild( IORegistryEntry * child,
 594                                 const IORegistryPlane * plane );
 595
 596 /*! @function detachAbove
 597     @abstract Detaches an entry from all its parent entries in a plane.
 598     @discussion This method calls detachFromParent in the entry for each of its parent entries in the plane.
 599     @param plane The plane object. */
 600
 601     virtual void detachAbove( const IORegistryPlane * plane );
 602
 603 /*! @function detachAll
 604     @abstract Detaches an entry and all its children recursively in a plane.
 605     @discussion This method breaks the registry connections for a subtree. detachAbove is called in the entry, and all child entries and their children in the plane.
 606     @param plane The plane object. */
 607
 608     virtual void detachAll( const IORegistryPlane * plane );
 609
 610     /* Name, location and path accessors */
 611
 612 /*! @function getName
 613     @abstract Returns the name assigned to the registry entry as a C-string.
 614     @discussion Entries can be named in a particular plane, or globally. If the entry is named in plane and the plane is specified that name will be returned, otherwise the global name is returned. The global name defaults to the entry's meta class name if it has not been named.
 615     @param plane The plane object, or zero for the global name.
 616     @result A C-string name, valid while the entry is retained. */
 617
 618     virtual const char * getName( const IORegistryPlane * plane = 0 ) const;
 619
 620 /*! @function copyName
 621     @abstract Returns the name assigned to the registry entry as an OSSymbol.
 622     @discussion Entries can be named in a particular plane, or globally. If the entry is named in plane and the plane is specified that name will be returned, otherwise the global name is returned. The global name defaults to the entry's meta class name if it has not been named.
 623     @param plane The plane object, or zero for the global name.
 624     @result A reference to an OSSymbol for the name, which should be released by the caller. */
 625
 626     virtual const OSSymbol * copyName(
 627                                 const IORegistryPlane * plane = 0 ) const;
 628
 629 /*! @function compareNames
 630     @abstract Compares the name of the entry with one or more names, and optionally returns the matching name.
 631     @discussion This method is called during IOService name matching and elsewhere to compare the entry's global name with a list of names, or a single name. A list of names may be passed as any OSCollection of OSStrings, while a single name may be passed an OSString, in the name parameter. compareNames will call the compareName method for each name, for overrides.
 632     @param name The name or names to compare with as any OSCollection (eg. OSArray, OSSet, OSDictionary) of OSStrings, or a single name may be passed an OSString.
 633     @param matched If the caller wants the successfully matched name returned, pass a non-zero pointer for the matched parameter and an OSString will be returned here. It should be released by the caller.
 634     @result True if one of the names compared true with the entry's global name. */
 635
 636     virtual bool compareNames( OSObject * name, OSString ** matched = 0 ) const;
 637
 638 /*! @function compareName
 639     @abstract Compares the name of the entry with one name, and optionally returns the matching name.
 640     @discussion This method is called during IOService name matching and elsewhere from the compareNames method. It should be overridden to provide non-standard name matching.
 641     @param name The name to compare with as an OSString.
 642     @param matched If the caller wants the successfully matched name returned, pass a non-zero pointer for the matched parameter and an OSString will be returned here. It should be released by the caller. Generally, this will be the same as the name parameter, but may not be if wildcards are used.
 643     @result True if the name compared true with the entry's global name. */
 644
 645     virtual bool compareName( OSString * name, OSString ** matched = 0 ) const;
 646
 647 /*! @function setName
 648     @abstract Sets a name for the registry entry, in a particular plane, or globally.
 649     @discussion Entries can be named in a particular plane, or globally. If the plane is specified the name applies only to that plane, otherwise the global name is set. The global name defaults to the entry's meta class name if it has not been named.
 650     @param name An OSSymbol which will be retained.
 651     @param plane The plane object, or zero to set the global name. */
 652
 653     virtual void setName( const OSSymbol * name,
 654                                 const IORegistryPlane * plane = 0 );
 655
 656 /*! @function setName
 657     @abstract Sets a name for the registry entry, in a particular plane, or globally.
 658     @discussion Entries can be named in a particular plane, or globally. If the plane is specified the name applies only to that plane, otherwise the global name is set. The global name defaults to the entry's meta class name if it has not been named.
 659     @param name A const C-string name which will be copied.
 660     @param plane The plane object, or zero to set the global name. */
 661
 662     virtual void setName( const char * name,
 663                                 const IORegistryPlane * plane = 0 );
 664
 665 /*! @function getLocation
 666     @abstract Returns the location string assigned to the registry entry as a C-string.
 667     @discussion Entries can given a location string in a particular plane, or globally. If the entry has had a location set in a plane and the plane is specified that location string will be returned, otherwise the global location string is returned. If no global location string has been set, zero is returned.
 668     @param plane The plane object, or zero for the global name.
 669     @result A C-string location string, valid while the entry is retained, or zero. */
 670
 671     virtual const char * getLocation( const IORegistryPlane * plane = 0 ) const;
 672
 673 /*! @function copyLocation
 674     @abstract Returns the location string assigned to the registry entry as an OSSymbol.
 675     @discussion Entries can given a location string in a particular plane, or globally. If the entry has had a location set in a plane and the plane is specified that location string will be returned, otherwise the global location string is returned. If no global location string has been set, zero is returned.
 676     @param plane The plane object, or zero for the global name.
 677     @result A reference to an OSSymbol for the location if one exists, which should be released by the caller, or zero. */
 678
 679     virtual const OSSymbol * copyLocation(
 680                                 const IORegistryPlane * plane = 0 ) const;
 681
 682 /*! @function setLocation
 683     @abstract Sets a location string for the registry entry, in a particular plane, or globally.
 684     @discussion Entries can be given a location string in a particular plane, or globally. If the plane is specified the location applies only to that plane, otherwise the global location is set. The location string may be used during path lookups of registry entries, to distinguish between sibling entries with the same name. The default IORegistryEntry parsing of location strings expects a list of hex numbers separated by commas, though subclasses of IORegistryEntry might do their own parsing.
 685     @param location A C-string location string which will be copied, or an OSSymbol which will be retained.
 686     @param plane The plane object, or zero to set the global location string. */
 687
 688     virtual void setLocation( const OSSymbol * location,
 689                                 const IORegistryPlane * plane = 0 );
 690     virtual void setLocation( const char * location,
 691                                 const IORegistryPlane * plane = 0 );
 692
 693 /*! @function getPath
 694     @abstract Create a path for a registry entry.
 695     @discussion The path for a registry entry is copied to the caller's buffer. The path describes the entry's attachment in a particular plane, which must be specified. The path begins with the plane name followed by a colon, and then followed by '/' separated path components for each of the entries between the root and the registry entry. Each component is constructed with the getPathComponent method called in each entry. An alias may also exist for the entry, which are described as properties in a registry entry found at /aliases in the plane. If a property value interpreted as a path in a call to IORegistryEntry::fromPath yields the entry, then the property name is used as the entry's path.
 696     @param path A char buffer allocated by the caller.
 697     @param length An in/out parameter - the caller sets the length of the buffer available, and getPath returns the total length of the path copied to the buffer.
 698     @param plane The plane object.
 699     @result getPath will fail if the entry is not attached in the plane, or if the buffer is not large enough to contain the path. */
 700
 701     virtual bool getPath( char * path, int * length,
 702                             const IORegistryPlane * plane) const;
 703
 704 /*! @function getPathComponent
 705     @abstract Create a path component for a registry entry.
 706     @discussion Each component of a path created with getPath is created with getPathComponent. The default implementation concatenates the entry's name in the the plane, with the "at" symbol and the location string of the entry in the plane if it has been set.
 707     @param path A char buffer allocated by the caller.
 708     @param length An in/out parameter - the caller sets the length of the buffer available, and getPathComponent returns the total length of the path component copied to the buffer.
 709     @param plane The plane object.
 710     @result true if the path fits into the supplied buffer or false on a overflow. */
 711
 712     virtual bool getPathComponent( char * path, int * length,
 713                                     const IORegistryPlane * plane ) const;
 714
 715 /*! @function fromPath
 716     @abstract Looks up a registry entry by path.
 717     @discussion This function parses paths to lookup registry entries. The path may begin with the <plane name>: created by getPath, or the plane may be set by the caller. If there are characters remaining unparsed after an entry has been looked up, this may be considered an invalid lookup, or those characters may be passed back to the caller and the lookup successful.
 718     @param path A C-string path.
 719     @param plane The plane to lookup up the path, or zero, in which case the path must begin with the plane name.
 720     @param residualPath If the path may contain residual characters after the last path component, the residual will be copied back to the caller's residualPath buffer. If there are residual characters and no residual buffer is specified, fromPath will fail.
 721     @param residualLength An in/out parameter - the caller sets the length of the residual buffer available, and fromPath returns the total length of the residual path copied to the buffer. If there is no residualBuffer (residualPath = 0) then residualLength may be zero also.
 722     @param fromEntry The lookup will proceed rooted at this entry if non-zero, otherwise it proceeds from the root of the plane.
 723     @result A retained registry entry is returned on success, or zero on failure. The caller should release the entry. */
 724
 725     static IORegistryEntry * fromPath(  const char * path,
 726                                         const IORegistryPlane * plane = 0,
 727                                         char * residualPath = 0,
 728                                         int * residualLength = 0,
 729                                         IORegistryEntry * fromEntry = 0 );
 730
 731 /*! @function fromPath
 732     @abstract Looks up a registry entry by relative path.
 733     @discussion This function looks up a entry below the called entry by a relative path. It is just a convenience that calls IORegistryEntry::fromPath with this as the fromEntry parameter.
 734     @param path See IORegistryEntry::fromPath.
 735     @param plane See IORegistryEntry::fromPath.
 736     @param residualPath See IORegistryEntry::fromPath.
 737     @param residualLength See IORegistryEntry::fromPath.
 738     @result See IORegistryEntry::fromPath. */
 739
 740     virtual IORegistryEntry * childFromPath( const char * path,
 741                                              const IORegistryPlane * plane = 0,
 742                                              char * residualPath = 0,
 743                                              int * residualLength = 0 );
 744
 745 /*! @function dealiasPath
 746     @abstract Strips any aliases from the head of path and returns the full path.
 747     @discussion If the path specified begins with an alias found in the /aliases entry, the value of the alias is returned, and a pointer into the passed in path after the alias is passed back to the caller. If an alias is not found, zero is returned and the path parameter is unchanged.
 748     @param opath An in/out paramter - the caller passes in a pointer to a C-string pointer to a path. If an alias is found, dealiasPath returns a pointer into the path just beyond the end of the alias.
 749     @param plane A plane object must be specified.
 750     @result A C-string pointer to the value of the alias if one is found, or zero if not. */
 751
 752     static const char * dealiasPath( const char ** opath,
 753                                     const IORegistryPlane * plane );
 754
 755     /* * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 756     /* * * * * * * * * * * * internals * * * * * * * * * * * */
 757     /* * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 758
 759 public:
 760     static IORegistryEntry * initialize( void );
 761     static const IORegistryPlane * makePlane( const char * name );
 762     // don't even think about using this
 763     virtual bool init( IORegistryEntry * from,
 764                                 const IORegistryPlane * inPlane );
 765 private:
 766     inline bool arrayMember( OSArray * set,
 767                             const IORegistryEntry * member,
 768                             unsigned int * index = 0 ) const;
 769
 770     bool makeLink( IORegistryEntry * to,
 771                     unsigned int relation,
 772                     const IORegistryPlane * plane ) const;
 773     void breakLink( IORegistryEntry * to,
 774                     unsigned int relation,
 775                     const IORegistryPlane * plane ) const;
 776
 777     virtual OSArray * getParentSetReference( const IORegistryPlane * plane )
 778                                                                         const;
 779     virtual OSArray * getChildSetReference( const IORegistryPlane * plane )
 780                                                                         const;
 781     virtual IORegistryEntry * getChildFromComponent( const char ** path,
 782                                 const IORegistryPlane * plane );
 783
 784     virtual const OSSymbol * hasAlias(  const IORegistryPlane * plane,
 785                                     char * opath = 0, int * length = 0 ) const;
 786     virtual const char * matchPathLocation( const char * cmp,
 787                                 const IORegistryPlane * plane );
 788
 789 };
 790
 791 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 792
 793 /*! @class IORegistryIterator : public OSIterator
 794     @abstract An iterator over the registry.
 795     @discussion An iterator that can traverse the children or parents of a registry entry in a plane, and recurse. Access to the registry is protected against multiple threads, but an IORegistryIterator instance is for use by one thread only. */
 796
 797 class IORegistryIterator : public OSIterator
 798 {
 799     OSDeclareAbstractStructors(IORegistryIterator)
 800
 801 private:
 802     struct IORegCursor {
 803         IORegCursor          *  next;
 804         IORegistryEntry      *  current;
 805         OSIterator           *  iter;
 806     };
 807     IORegCursor                 start;
 808     IORegCursor           *     where;
 809     IORegistryEntry       *     root;
 810     OSOrderedSet          *     done;
 811     const IORegistryPlane *     plane;
 812     IOOptionBits                options;
 813
 814     virtual void free( void );
 815
 816 public:
 817 /*! @function iterateOver
 818     @abstract Create an iterator rooted at a given registry entry.
 819     @discussion This method creates an IORegistryIterator that is set up with options to iterate children or parents of a root entry, and to recurse automatically into entries as they are returned, or only when instructed. The iterator object keeps track of entries that have been recursed into previously to avoid loops.
 820     @param start The root entry to begin the iteration at.
 821     @param plane A plane object must be specified.
 822     @param options kIORegistryIterateRecursively may be set to recurse automatically into each entry as it is returned. This option affects the behaviour of the getNextObject method, which is defined in the OSIterator superclass. Other methods will override this behaviour. kIORegistryIterateParents may be set to iterate the parents of each entry, by default the children are iterated.
 823     @result A created IORegistryIterator instance, to be released by the caller when it has finished with it. */
 824
 825     static IORegistryIterator * iterateOver( IORegistryEntry * start,
 826                                              const IORegistryPlane * plane,
 827                                              IOOptionBits options = 0 );
 828
 829 /*! @function iterateOver
 830     @abstract Create an iterator rooted at the registry root.
 831     @discussion This method creates an IORegistryIterator that is set up with options to iterate children of the registry root entry, and to recurse automatically into entries as they are returned, or only when instructed. The iterator object keeps track of entries that have been recursed into previously to avoid loops.
 832     @param plane A plane object must be specified.
 833     @param options kIORegistryIterateRecursively may be set to recurse automatically into each entry as it is returned. This option affects the behaviour of the getNextObject method, which is defined in the OSIterator superclass. Other methods will override this behaviour. kIORegistryIterateParents may be set to iterate the parents of each entry, by default the children are iterated.
 834     @result A created IORegistryIterator instance, to be released by the caller when it has finished with it. */
 835
 836     static IORegistryIterator * iterateOver( const IORegistryPlane * plane,
 837                                              IOOptionBits options = 0 );
 838
 839 /*! @function getNextObject
 840     @abstract Return the next object in the registry iteration.
 841     @discussion This method calls either getNextObjectFlat or getNextObjectRecursive depending on the options the iterator was created with. This implements the OSIterator defined getNextObject method. The object returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it.
 842     @result The next registry entry in the iteration (the current entry), or zero if the iteration has finished at this level of recursion. The entry returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it. */
 843
 844     virtual IORegistryEntry * getNextObject( void );
 845
 846 /*! @function getNextObjectFlat
 847     @abstract Return the next object in the registry iteration, ignoring the kIORegistryIterateRecursively option.
 848     @discussion This method returns the next child, or parent if the kIORegistryIterateParents option was used to create the iterator, of the current root entry. The object returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it.
 849     @result The next registry entry in the iteration (the current entry), or zero if the iteration has finished at this level of recursion, or the iteration is invalid (see isValid). The entry returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it. */
 850
 851     virtual IORegistryEntry * getNextObjectFlat( void );
 852
 853 /*! @function getNextObjectRecursive
 854     @abstract Return the next object in the registry iteration, and enter it.
 855     @discussion If the iterator has a current entry, and the iterator has not already entered previously, enterEntry is called to recurse into it, ie. make it the new root, and the next child, or parent if the kIORegistryIterateParents option was used to create the iterator, at this new level of recursion is returned. If there is no current entry at this level of recursion, exitEntry is called and the process repeats, until the iteration returns to the entry the iterator was created with and zero is returned. The object returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it.
 856     @result The next registry entry in the iteration (the current entry), or zero if its finished, or the iteration is invalid (see isValid). The entry returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it. */
 857
 858     virtual IORegistryEntry * getNextObjectRecursive( void );
 859
 860 /*! @function getCurrentEntry
 861     @abstract Return the current entry in the registry iteration.
 862     @discussion This method returns the current entry, last returned by getNextObject et al. The object returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it. If the iteration is no longer valid (see isValid), the current entry is zero.
 863     @result The current registry entry in the iteration, or zero if the last iteration returned zero, or the iteration is invalid (see isValid). The entry returned is retained while the iterator is pointing at it (its the current entry), or recursing into it. The caller should not release it. */
 864
 865     virtual IORegistryEntry * getCurrentEntry( void );
 866
 867 /*! @function enterEntry
 868     @abstract Recurse into the current entry in the registry iteration.
 869     @discussion This method makes the current entry, ie. the last entry returned by getNextObject et al., the root in a new level of recursion. */
 870
 871     virtual void enterEntry( void );
 872
 873 /*! @function enterEntry
 874     @abstract Recurse into the current entry in the registry iteration.
 875     @discussion This method recurses into an entry as with enterEntry, but also switches from the current plane to a new one set by the caller.
 876     @param plane The new plane to switch into. */
 877
 878     virtual void enterEntry( const IORegistryPlane * plane );
 879
 880 /*! @function exitEntry
 881     @abstract Exits a level of recursion, restoring the current entry.
 882     @discussion This method undoes an enterEntry, restoring the current entry. If there are no more levels of recursion to exit false is returned, otherwise true is returned.
 883     @result true if a level of recursion was undone, false if no recursive levels are left in the iteration. */
 884
 885     virtual bool exitEntry( void );
 886
 887 /*! @function reset
 888     @abstract Exits all levels of recursion, restoring the iterator to its state at creation.
 889     @discussion This method exits all levels of recursion, and restores the iterator to its state at creation. */
 890
 891     virtual void reset( void );
 892
 893 /*! @function isValid
 894     @abstract Checks that no registry changes have invalidated the iteration.
 895     @discussion If a registry iteration is invalidated by changes to the registry, it will be made invalid, the currentEntry will be considered zero, and further calls to getNextObject et al. will return zero. The iterator should be reset to restart the iteration when this happens.
 896     @result false if the iterator has been invalidated by changes to the registry, true otherwise. */
 897
 898     virtual bool isValid( void );
 899
 900 /*! @function iterateAll
 901     @abstract Iterates all entries (with getNextObject) and returns a set of all returned entries.
 902     @discussion This method will reset, then iterate all entries in the iteration (with getNextObject) until successful (ie. the iterator is valid at the end of the iteration).
 903     @result A set of entries returned by the iteration. The caller should release the set when it has finished with it. Zero is returned on a resource failure. */
 904
 905     virtual OSOrderedSet * iterateAll( void );
 906 };
 907
 908 #endif /* _IOKIT_IOREGISTRYENTRY_H */