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source: vbox/trunk/include/iprt/handletable.h@ 103224

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1/** @file
2 * IPRT - Handle Tables.
3 */
4
5/*
6 * Copyright (C) 2008-2023 Oracle and/or its affiliates.
7 *
8 * This file is part of VirtualBox base platform packages, as
9 * available from https://www.virtualbox.org.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation, in version 3 of the
14 * License.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, see <https://www.gnu.org/licenses>.
23 *
24 * The contents of this file may alternatively be used under the terms
25 * of the Common Development and Distribution License Version 1.0
26 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
27 * in the VirtualBox distribution, in which case the provisions of the
28 * CDDL are applicable instead of those of the GPL.
29 *
30 * You may elect to license modified versions of this file under the
31 * terms and conditions of either the GPL or the CDDL or both.
32 *
33 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
34 */
35
36#ifndef IPRT_INCLUDED_handletable_h
37#define IPRT_INCLUDED_handletable_h
38#ifndef RT_WITHOUT_PRAGMA_ONCE
39# pragma once
40#endif
41
42#include <iprt/cdefs.h>
43#include <iprt/types.h>
44
45RT_C_DECLS_BEGIN
46
47/** @defgroup grp_rt_handletable RTHandleTable - Handle Tables
48 * @ingroup grp_rt
49 * @{
50 */
51
52/**
53 * Callback for retaining an object during the lookup and free calls.
54 *
55 * This callback is executed when a handle is being looked up in one
56 * way or another from behind the handle table lock. This allows you
57 * to increase the reference (or some equivalent thing) during the
58 * handle lookup and thereby eliminate any race with anyone trying
59 * to free the handle.
60 *
61 * Note that there is no counterpart to this callback, so if you make
62 * use of this you'll have to release the object manually of course.
63 *
64 * Another use of this callback is to do some extra access checking.
65 * Use the return code to indicate whether the lookup should fail
66 * or not (no object is returned on faliure, naturally).
67 *
68 * @returns IPRT status code for the lookup (the caller won't see this).
69 *
70 * @param hHandleTable The handle table handle.
71 * @param pvObj The object which has been looked up.
72 * @param pvCtx The context argument if the handle table was created with the
73 * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
74 * @param pvUser The user context argument specified when creating the table.
75 */
76typedef DECLCALLBACKTYPE(int, FNRTHANDLETABLERETAIN,(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, void *pvUser));
77/** Pointer to a FNHANDLETABLERETAIN. */
78typedef FNRTHANDLETABLERETAIN *PFNRTHANDLETABLERETAIN;
79
80/**
81 * Callback for deleting a left over object during RTHandleTableDestroy.
82 *
83 * @param hHandleTable The handle table handle.
84 * @param h The handle.
85 * @param pvObj The object.
86 * @param pvCtx The context argument if the handle table was created with the
87 * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
88 * @param pvUser The user context argument specified when creating the table.
89 *
90 */
91typedef DECLCALLBACKTYPE(void, FNRTHANDLETABLEDELETE,(RTHANDLETABLE hHandleTable, uint32_t h, void *pvObj, void *pvCtx, void *pvUser));
92/** Pointer to a FNRTHANDLETABLEDELETE. */
93typedef FNRTHANDLETABLEDELETE *PFNRTHANDLETABLEDELETE;
94
95
96/** @name RTHandleTableCreateEx flags
97 * @{ */
98/** Whether the handle table entries takes a context or not.
99 *
100 * This can be useful for associating a handle with for instance a process or
101 * similar in order to prevent anyone but the owner from using the handle.
102 *
103 * Setting this means you will have to use the WithCtx functions to do the
104 * handle management. */
105#define RTHANDLETABLE_FLAGS_CONTEXT RT_BIT_32(0)
106/** Whether the handle table should take care of the serialization (IRQ unsafe).
107 * If not specified the caller will have to take care of that. */
108#define RTHANDLETABLE_FLAGS_LOCKED RT_BIT_32(1)
109/** Like RTHANDLETABLE_FLAGS_LOCKED, except it's IRQ safe.
110 * A side-effect is that callbacks may be called with IRQs disabled. */
111#define RTHANDLETABLE_FLAGS_LOCKED_IRQ_SAFE RT_BIT_32(2)
112/** The mask of valid flags. */
113#define RTHANDLETABLE_FLAGS_MASK UINT32_C(0x00000007)
114/** @} */
115
116
117/**
118 * Creates a handle table.
119 *
120 * The handle table translates a 32-bit handle into an object pointer,
121 * optionally calling you back so you can retain the object without
122 * racing RTHandleTableFree.
123 *
124 * @returns IPRT status code and on success a handle table handle will be stored at the
125 * location phHandleTable points at.
126 *
127 * @param phHandleTable Where to store the handle table handle on success.
128 * @param fFlags Flags, see RTHANDLETABLE_FLAGS_*.
129 * @param uBase The handle base value. This is the value of the
130 * first handle to be returned.
131 * @param cMax The max number of handles. When exceeded the RTHandleTableAlloc
132 * or RTHandleTableAllocWithCtx calls will fail. Note that this
133 * number will be rounded up to a multiple of the sub-table size,
134 * or if it's too close to UINT32_MAX it will be rounded down.
135 * @param pfnRetain Optional retain callback that will be called from behind the
136 * lock (if any) during lookup.
137 * @param pvUser The user argument to the retain callback.
138 */
139RTDECL(int) RTHandleTableCreateEx(PRTHANDLETABLE phHandleTable, uint32_t fFlags, uint32_t uBase, uint32_t cMax,
140 PFNRTHANDLETABLERETAIN pfnRetain, void *pvUser);
141
142/**
143 * A simplified version of the RTHandleTableCreateEx API.
144 *
145 * It assumes a max of about 64K handles with 1 being the base. The table
146 * access will serialized (RTHANDLETABLE_FLAGS_LOCKED).
147 *
148 * @returns IPRT status code and *phHandleTable.
149 *
150 * @param phHandleTable Where to store the handle table handle on success.
151 */
152RTDECL(int) RTHandleTableCreate(PRTHANDLETABLE phHandleTable);
153
154/**
155 * Destroys a handle table.
156 *
157 * If any entries are still in used the pfnDelete callback will be invoked
158 * on each of them (if specfied) to allow to you clean things up.
159 *
160 * @returns IPRT status code
161 *
162 * @param hHandleTable The handle to the handle table.
163 * @param pfnDelete Function to be called back on each handle still in use. Optional.
164 * @param pvUser The user argument to pfnDelete.
165 */
166RTDECL(int) RTHandleTableDestroy(RTHANDLETABLE hHandleTable, PFNRTHANDLETABLEDELETE pfnDelete, void *pvUser);
167
168/**
169 * Allocates a handle from the handle table.
170 *
171 * @returns IPRT status code, almost any.
172 * @retval VINF_SUCCESS on success.
173 * @retval VERR_NO_MEMORY if we failed to extend the handle table.
174 * @retval VERR_NO_MORE_HANDLES if we're out of handles.
175 *
176 * @param hHandleTable The handle to the handle table.
177 * @param pvObj The object to associate with the new handle.
178 * This must be aligned on a 4 byte boundary.
179 * @param ph Where to return the handle on success.
180 *
181 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
182 */
183RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph);
184
185/**
186 * Looks up a handle.
187 *
188 * @returns The object pointer on success. NULL on failure.
189 *
190 * @param hHandleTable The handle to the handle table.
191 * @param h The handle to lookup.
192 *
193 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
194 */
195RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h);
196
197/**
198 * Looks up and frees a handle.
199 *
200 * @returns The object pointer on success. NULL on failure.
201 *
202 * @param hHandleTable The handle to the handle table.
203 * @param h The handle to lookup.
204 *
205 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
206 */
207RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h);
208
209/**
210 * Allocates a handle from the handle table.
211 *
212 * @returns IPRT status code, almost any.
213 * @retval VINF_SUCCESS on success.
214 * @retval VERR_NO_MEMORY if we failed to extend the handle table.
215 * @retval VERR_NO_MORE_HANDLES if we're out of handles.
216 *
217 * @param hHandleTable The handle to the handle table.
218 * @param pvObj The object to associate with the new handle.
219 * This must be aligned on a 4 byte boundary.
220 * @param pvCtx The context to associate with the new handle.
221 * @param ph Where to return the handle on success.
222 *
223 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
224 */
225RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, uint32_t *ph);
226
227/**
228 * Looks up a handle.
229 *
230 * @returns The object pointer on success. NULL on failure.
231 *
232 * @param hHandleTable The handle to the handle table.
233 * @param h The handle to lookup.
234 * @param pvCtx The handle context, this must match what was given on allocation.
235 *
236 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
237 */
238RTDECL(void *) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
239
240/**
241 * Looks up and frees a handle.
242 *
243 * @returns The object pointer on success. NULL on failure.
244 *
245 * @param hHandleTable The handle to the handle table.
246 * @param h The handle to lookup.
247 * @param pvCtx The handle context, this must match what was given on allocation.
248 *
249 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
250 */
251RTDECL(void *) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
252
253/** @} */
254
255RT_C_DECLS_END
256
257
258#endif /* !IPRT_INCLUDED_handletable_h */
259
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