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source: vbox/trunk/include/iprt/handletable.h@ 30246

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1/** @file
2 * IPRT - Handle Tables.
3 */
4
5/*
6 * Copyright (C) 2008 Oracle Corporation
7 *
8 * This file is part of VirtualBox Open Source Edition (OSE), as
9 * available from http://www.virtualbox.org. This file is free software;
10 * you can redistribute it and/or modify it under the terms of the GNU
11 * General Public License (GPL) as published by the Free Software
12 * Foundation, in version 2 as it comes in the "COPYING" file of the
13 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
14 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
15 *
16 * The contents of this file may alternatively be used under the terms
17 * of the Common Development and Distribution License Version 1.0
18 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
19 * VirtualBox OSE distribution, in which case the provisions of the
20 * CDDL are applicable instead of those of the GPL.
21 *
22 * You may elect to license modified versions of this file under the
23 * terms and conditions of either the GPL or the CDDL or both.
24 */
25
26#ifndef ___iprt_handletable_h
27#define ___iprt_handletable_h
28
29#include <iprt/cdefs.h>
30#include <iprt/types.h>
31
32RT_C_DECLS_BEGIN
33
34/** @defgroup grp_rt_handletable RTHandleTable - Handle Tables
35 * @ingroup grp_rt
36 * @{
37 */
38
39/**
40 * Callback for retaining an object during the lookup and free calls.
41 *
42 * This callback is executed when a handle is being looked up in one
43 * way or another from behind the handle table lock. This allows you
44 * to increase the reference (or some equivalent thing) during the
45 * handle lookup and thereby eliminate any race with anyone trying
46 * to free the handle.
47 *
48 * Note that there is no counterpart to this callback, so if you make
49 * use of this you'll have to release the object manually of course.
50 *
51 * Another use of this callback is to do some extra access checking.
52 * Use the return code to indicate whether the lookup should fail
53 * or not (no object is returned on faliure, naturally).
54 *
55 * @returns IPRT status code for the lookup (the caller won't see this).
56 *
57 * @param hHandleTable The handle table handle.
58 * @param pvObj The object which has been looked up.
59 * @param pvCtx The context argument if the handle table was created with the
60 * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
61 * @param pvUser The user context argument specified when creating the table.
62 */
63typedef DECLCALLBACK(int) FNRTHANDLETABLERETAIN(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, void *pvUser);
64/** Pointer to a FNHANDLETABLERETAIN. */
65typedef FNRTHANDLETABLERETAIN *PFNRTHANDLETABLERETAIN;
66
67/**
68 * Callback for deleting a left over object during RTHandleTableDestroy.
69 *
70 * @param hHandleTable The handle table handle.
71 * @param h The handle.
72 * @param pvObj The object.
73 * @param pvCtx The context argument if the handle table was created with the
74 * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
75 * @param pvUser The user context argument specified when creating the table.
76 *
77 */
78typedef DECLCALLBACK(void) FNRTHANDLETABLEDELETE(RTHANDLETABLE hHandleTable, uint32_t h, void *pvObj, void *pvCtx, void *pvUser);
79/** Pointer to a FNRTHANDLETABLEDELETE. */
80typedef FNRTHANDLETABLEDELETE *PFNRTHANDLETABLEDELETE;
81
82
83/** @name RTHandleTableCreateEx flags
84 * @{ */
85/** Whether the handle table entries takes a context or not.
86 *
87 * This can be useful for associating a handle with for instance a process or
88 * similar in order to prevent anyone but the owner from using the handle.
89 *
90 * Setting this means you will have to use the WithCtx functions to do the
91 * handle management. */
92#define RTHANDLETABLE_FLAGS_CONTEXT RT_BIT_32(0)
93/** Whether the handle table should take care of the serialization.
94 * If not specfied the caller will have to take care of that. */
95#define RTHANDLETABLE_FLAGS_LOCKED RT_BIT_32(1)
96/** The mask of valid flags. */
97#define RTHANDLETABLE_FLAGS_MASK UINT32_C(0x00000003)
98/* @} */
99
100
101/**
102 * Creates a handle table.
103 *
104 * The handle table translates a 32-bit handle into an object pointer,
105 * optionally calling you back so you can retain the object without
106 * racing RTHandleTableFree.
107 *
108 * @returns IPRT status code and on success a handle table handle will be stored at the
109 * location phHandleTable points at.
110 *
111 * @param phHandleTable Where to store the handle table handle on success.
112 * @param fFlags Flags, see RTHANDLETABLE_FLAGS_*.
113 * @param uBase The handle base value. This is the value of the
114 * first handle to be returned.
115 * @param cMax The max number of handles. When exceeded the RTHandleTableAlloc
116 * or RTHandleTableAllocWithCtx calls will fail. Note that this
117 * number will be rounded up to a multiple of the sub-table size,
118 * or if it's too close to UINT32_MAX it will be rounded down.
119 * @param pfnRetain Optional retain callback that will be called from behind the
120 * lock (if any) during lookup.
121 * @param pvUser The user argument to the retain callback.
122 */
123RTDECL(int) RTHandleTableCreateEx(PRTHANDLETABLE phHandleTable, uint32_t fFlags, uint32_t uBase, uint32_t cMax,
124 PFNRTHANDLETABLERETAIN pfnRetain, void *pvUser);
125
126/**
127 * A simplified version of the RTHandleTableCreateEx API.
128 *
129 * It assumes a max of about 64K handles with 1 being the base. The table
130 * access will serialized (RTHANDLETABLE_FLAGS_LOCKED).
131 *
132 * @returns IPRT status code and *phHandleTable.
133 *
134 * @param phHandleTable Where to store the handle table handle on success.
135 */
136RTDECL(int) RTHandleTableCreate(PRTHANDLETABLE phHandleTable);
137
138/**
139 * Destroys a handle table.
140 *
141 * If any entries are still in used the pfnDelete callback will be invoked
142 * on each of them (if specfied) to allow to you clean things up.
143 *
144 * @returns IPRT status code
145 *
146 * @param hHandleTable The handle to the handle table.
147 * @param pfnDelete Function to be called back on each handle still in use. Optional.
148 * @param pvUser The user argument to pfnDelete.
149 */
150RTDECL(int) RTHandleTableDestroy(RTHANDLETABLE hHandleTable, PFNRTHANDLETABLEDELETE pfnDelete, void *pvUser);
151
152/**
153 * Allocates a handle from the handle table.
154 *
155 * @returns IPRT status code, almost any.
156 * @retval VINF_SUCCESS on success.
157 * @retval VERR_NO_MEMORY if we failed to extend the handle table.
158 * @retval VERR_NO_MORE_HANDLES if we're out of handles.
159 *
160 * @param hHandleTable The handle to the handle table.
161 * @param pvObj The object to associate with the new handle.
162 * This must be aligned on a 4 byte boundrary.
163 * @param ph Where to return the handle on success.
164 *
165 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
166 */
167RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph);
168
169/**
170 * Looks up a handle.
171 *
172 * @returns The object pointer on success. NULL on failure.
173 *
174 * @param hHandleTable The handle to the handle table.
175 * @param h The handle to lookup.
176 *
177 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
178 */
179RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h);
180
181/**
182 * Looks up and frees a handle.
183 *
184 * @returns The object pointer on success. NULL on failure.
185 *
186 * @param hHandleTable The handle to the handle table.
187 * @param h The handle to lookup.
188 *
189 * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
190 */
191RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h);
192
193/**
194 * Allocates a handle from the handle table.
195 *
196 * @returns IPRT status code, almost any.
197 * @retval VINF_SUCCESS on success.
198 * @retval VERR_NO_MEMORY if we failed to extend the handle table.
199 * @retval VERR_NO_MORE_HANDLES if we're out of handles.
200 *
201 * @param hHandleTable The handle to the handle table.
202 * @param pvObj The object to associate with the new handle.
203 * This must be aligned on a 4 byte boundrary.
204 * @param pvCtx The context to associate with the new handle.
205 * @param ph Where to return the handle on success.
206 *
207 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
208 */
209RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, uint32_t *ph);
210
211/**
212 * Looks up a handle.
213 *
214 * @returns The object pointer on success. NULL on failure.
215 *
216 * @param hHandleTable The handle to the handle table.
217 * @param h The handle to lookup.
218 * @param pvCtx The handle context, this must match what was given on allocation.
219 *
220 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
221 */
222RTDECL(void *) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
223
224/**
225 * Looks up and frees a handle.
226 *
227 * @returns The object pointer on success. NULL on failure.
228 *
229 * @param hHandleTable The handle to the handle table.
230 * @param h The handle to lookup.
231 * @param pvCtx The handle context, this must match what was given on allocation.
232 *
233 * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
234 */
235RTDECL(void *) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
236
237/** @} */
238
239RT_C_DECLS_END
240
241
242#endif
243
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