1/*
2 * Copyright (c) 2000 Apple Computer, 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
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25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* IOCollectionIterator.h created by gvdl on Fri 1998-10-30 */
29
30#ifndef _OS_OSCOLLECTIONITERATOR_H
31#define _OS_OSCOLLECTIONITERATOR_H
32
33#include <libkern/c++/OSIterator.h>
34
35class OSCollection;
36
37/*!
38 * @header
39 *
40 * @abstract
41 * This header declares the OSCollectionIterator collection class.
42 */
43
44
45/*!
46 * @class OSCollectionIterator
47 *
48 * @discussion
49 * OSCollectionIterator defines a consistent mechanism to iterate
50 * through the objects of an OSCollection.
51 * It expands on the basic interface of
52 * @link //apple_ref/cpp/class/OSIterator OSIterator@/link
53 * to allow association of an iterator with a specific collection.
54 *
55 * To use an OSCollectionIterator, you create it with the collection
56 * to be iterated, then call
57 * @link //apple_ref/cpp/class/OSIterator OSIterator@/link
58 * as long as it returns an object:
59 *
60 * @textblock
61 * <pre>
62 * OSCollectionIterator * iterator =
63 * OSCollectionIterator::withCollection(myCollection);
64 * OSObject * object;
65 * while (object = iterator->getNextObject()) {
66 * // do something with object
67 * }
68 * // optional
69 * if (!iterator->isValid()) {
70 * // report that collection changed during iteration
71 * }
72 * iterator->release();
73 * </pre>
74 * @/textblock
75 *
76 * Note that when iterating associative collections,
77 * the objects returned by <code>getNextObject</code> are keys;
78 * if you want to work with the associated values,
79 * simply look them up in the collection with the keys.
80 *
81 * <b>Use Restrictions</b>
82 *
83 * With very few exceptions in the I/O Kit, all Libkern-based C++
84 * classes, functions, and macros are <b>unsafe</b>
85 * to use in a primary interrupt context.
86 * Consult the I/O Kit documentation related to primary interrupts
87 * for more information.
88 *
89 * OSCollectionIterator provides no concurrency protection.
90 */
91class OSCollectionIterator : public OSIterator
92{
93 OSDeclareDefaultStructors(OSCollectionIterator)
94
95protected:
96// xx-review: Do we want to document these?
97 const OSCollection * collection;
98 void * collIterator;
99 unsigned int initialUpdateStamp;
100 bool valid;
101
102public:
103 /*!
104 * @function withCollection
105 *
106 * @abstract
107 * Creates and initializes an OSCollectionIterator
108 * for the provided collection object.
109 *
110 * @param inColl The OSCollection-derived collection object to be iteratated.
111 *
112 * @result
113 * A new instance of OSCollectionIterator, or <code>NULL</code> on failure.
114 */
115 static OSCollectionIterator * withCollection(const OSCollection * inColl);
116
117
118 /*!
119 * @function initWithCollection
120 *
121 * @abstract
122 * Initializes an OSCollectionIterator
123 * for the provided collection object.
124 *
125 * @param inColl The OSCollection-derived collection object to be iteratated.
126 * @result
127 * <code>true</code> if the initialization was successful,
128 * or <code>false</code> on failure.
129 *
130 * @discussion
131 * Not for general use. Use the static instance creation method
132 * <code>@link withCollection withCollection@/link</code> instead.
133 */
134 virtual bool initWithCollection(const OSCollection * inColl);
135
136
137 /*!
138 * @function free
139 *
140 * @abstract
141 * Releases or deallocates any resources used
142 * by the OSCollectionIterator object.
143 *
144 * @discussion
145 * This function should not be called directly;
146 * use
147 * <code>@link
148 * //apple_ref/cpp/instm/OSObject/release/virtualvoid/()
149 * release@/link</code>
150 * instead.
151 */
152 virtual void free() APPLE_KEXT_OVERRIDE;
153
154
155 /*!
156 * @function reset
157 *
158 * @abstract
159 * Resets the iterator to the beginning of the collection,
160 * as if it had just been created.
161 */
162 virtual void reset() APPLE_KEXT_OVERRIDE;
163
164
165 /*!
166 * @function isValid
167 *
168 * @abstract
169 * Checks that the collection hasn't been modified during iteration.
170 *
171 * @return
172 * <code>true</code> if the iterator is valid for continued use,
173 * <code>false</code> otherwise
174 * (typically because the iteration context has been modified).
175 */
176 virtual bool isValid() APPLE_KEXT_OVERRIDE;
177
178
179 /*!
180 * @function getNextObject
181 *
182 * @abstract
183 * Advances to and returns the next object in the iteration.
184 *
185 * @return
186 * The next object in the iteration context,
187 * <code>NULL</code> if there is no next object
188 * or if the iterator is no longer valid.
189 *
190 * @discussion
191 * This function first calls
192 * <code>@link //apple_ref/cpp/instm/OSCollectionIterator/isValid/virtualbool/()
193 * isValid@/link</code>
194 * and returns <code>NULL</code> if that function
195 * returns <code>false</code>.
196 *
197 * Subclasses must implement this pure virtual function
198 * to check for validity with
199 * <code>@link
200 * //apple_ref/cpp/instm/OSCollectionIterator/isValid/virtualbool/()
201 * isValid@/link</code>,
202 * and then to advance the iteration context to the next object (if any)
203 * and return that next object, or <code>NULL</code> if there is none.
204 */
205 virtual OSObject * getNextObject() APPLE_KEXT_OVERRIDE;
206};
207
208#endif /* !_OS_OSCOLLECTIONITERATOR_H */
209