handletablesimple.cpp@ 34497

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1	/* $Id: handletablesimple.cpp 28800 2010-04-27 08:22:32Z vboxsync $ */
2	/** @file
3	* IPRT - Handle Tables.
4	*/
5
6	/*
7	* Copyright (C) 2008 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*******************************************************************************
29	* Header Files *
30	*******************************************************************************/
31	#include <iprt/handletable.h>
32	#include "internal/iprt.h"
33
34	#include <iprt/mem.h>
35	#include <iprt/spinlock.h>
36	#include <iprt/err.h>
37	#include <iprt/assert.h>
38	#include <iprt/param.h>
39	#include <iprt/string.h>
40	#include <iprt/asm.h>
41	#include "internal/magics.h"
42	#include "handletable.h"
43
44
45	RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void pvObj, uint32_t ph)
46	{
47	/* validate the input */
48	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
49	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
50	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
51	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), VERR_INVALID_FUNCTION);
52	AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
53	AssertPtrReturn(ph, VERR_INVALID_POINTER);
54	*ph = pThis->uBase - 1;
55
56	/*
57	* Allocation loop.
58	*/
59	RTSPINLOCKTMP Tmp /= no init /;
60	rtHandleTableLock(pThis, &Tmp);
61
62	int rc;
63	do
64	{
65	/*
66	* Try grab a free entry from the head of the free list.
67	*/
68	uint32_t i = pThis->iFreeHead;
69	if (i != NIL_RTHT_INDEX)
70	{
71	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, i);
72	Assert(pFree);
73	if (i == pThis->iFreeTail)
74	pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
75	else
76	pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
77	pThis->cCurAllocated++;
78	Assert(pThis->cCurAllocated <= pThis->cCur);
79
80	/*
81	* Setup the entry and return.
82	*/
83	PRTHTENTRY pEntry = (PRTHTENTRY)pFree;
84	pEntry->pvObj = pvObj;
85	*ph = i + pThis->uBase;
86	rc = VINF_SUCCESS;
87	}
88	/*
89	* Must expand the handle table, unless it's full.
90	*/
91	else if (pThis->cCur >= pThis->cMax)
92	{
93	rc = VERR_NO_MORE_HANDLES;
94	Assert(pThis->cCur == pThis->cCurAllocated);
95	}
96	else
97	{
98	/*
99	* Do we have to expand the 1st level table too?
100	*/
101	uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
102	uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
103	? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
104	: 0;
105	if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
106	cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
107	Assert(!cLevel1 \|\| pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
108
109	/* leave the lock (never do fancy stuff from behind a spinlock). */
110	rtHandleTableUnlock(pThis, &Tmp);
111
112	/*
113	* Do the allocation(s).
114	*/
115	rc = VERR_TRY_AGAIN;
116	void **papvLevel1 = NULL;
117	if (cLevel1)
118	{
119	papvLevel1 = (void *)RTMemAlloc(sizeof(void ) * cLevel1);
120	if (!papvLevel1)
121	return VERR_NO_MEMORY;
122	}
123
124	PRTHTENTRY paTable = (PRTHTENTRY)RTMemAlloc(sizeof(paTable) RTHT_LEVEL2_ENTRIES);
125	if (!paTable)
126	{
127	RTMemFree(papvLevel1);
128	return VERR_NO_MEMORY;
129	}
130
131	/* re-enter the lock. */
132	rtHandleTableLock(pThis, &Tmp);
133
134	/*
135	* Insert the new bits, but be a bit careful as someone might have
136	* raced us expanding the table.
137	*/
138	/* deal with the 1st level lookup expansion first */
139	if (cLevel1)
140	{
141	Assert(papvLevel1);
142	if (cLevel1 > pThis->cLevel1)
143	{
144	/* Replace the 1st level table. */
145	memcpy(papvLevel1, pThis->papvLevel1, sizeof(void ) pThis->cLevel1);
146	memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void ) (cLevel1 - pThis->cLevel1));
147	pThis->cLevel1 = cLevel1;
148	void **papvTmp = pThis->papvLevel1;
149	pThis->papvLevel1 = papvLevel1;
150	papvLevel1 = papvTmp;
151	}
152
153	/* free the obsolete one (outside the lock of course) */
154	rtHandleTableUnlock(pThis, &Tmp);
155	RTMemFree(papvLevel1);
156	rtHandleTableLock(pThis, &Tmp);
157	}
158
159	/* insert the table we allocated. */
160	uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
161	if ( iLevel1New < pThis->cLevel1
162	&& pThis->cCur < pThis->cMax)
163	{
164	pThis->papvLevel1[iLevel1New] = paTable;
165
166	/* link all entries into a free list. */
167	Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
168	for (i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
169	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
170	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
171
172	/* join the free list with the other. */
173	if (pThis->iFreeTail == NIL_RTHT_INDEX)
174	pThis->iFreeHead = pThis->cCur;
175	else
176	{
177	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
178	Assert(pPrev);
179	RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
180	}
181	pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
182
183	pThis->cCur += RTHT_LEVEL2_ENTRIES;
184	}
185	else
186	{
187	/* free the table (raced someone, and we lost). */
188	rtHandleTableUnlock(pThis, &Tmp);
189	RTMemFree(paTable);
190	rtHandleTableLock(pThis, &Tmp);
191	}
192
193	rc = VERR_TRY_AGAIN;
194	}
195	} while (rc == VERR_TRY_AGAIN);
196
197	rtHandleTableUnlock(pThis, &Tmp);
198
199	return rc;
200	}
201	RT_EXPORT_SYMBOL(RTHandleTableAlloc);
202
203
204	RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h)
205	{
206	/* validate the input */
207	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
208	AssertPtrReturn(pThis, NULL);
209	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
210	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
211
212	void *pvObj = NULL;
213
214	/* acquire the lock */
215	RTSPINLOCKTMP Tmp /= no init /;
216	rtHandleTableLock(pThis, &Tmp);
217
218	/*
219	* Perform the lookup and retaining.
220	*/
221	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
222	if (pEntry)
223	{
224	pvObj = pEntry->pvObj;
225	if (!RTHT_IS_FREE(pvObj))
226	{
227	if (pThis->pfnRetain)
228	{
229	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
230	if (RT_FAILURE(rc))
231	pvObj = NULL;
232	}
233	}
234	else
235	pvObj = NULL;
236	}
237
238	/* release the lock */
239	rtHandleTableUnlock(pThis, &Tmp);
240	return pvObj;
241	}
242	RT_EXPORT_SYMBOL(RTHandleTableLookup);
243
244
245	RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h)
246	{
247	/* validate the input */
248	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
249	AssertPtrReturn(pThis, NULL);
250	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
251	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
252
253	void *pvObj = NULL;
254
255	/* acquire the lock */
256	RTSPINLOCKTMP Tmp /= no init /;
257	rtHandleTableLock(pThis, &Tmp);
258
259	/*
260	* Perform the lookup and retaining.
261	*/
262	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
263	if (pEntry)
264	{
265	pvObj = pEntry->pvObj;
266	if (!RTHT_IS_FREE(pvObj))
267	{
268	if (pThis->pfnRetain)
269	{
270	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
271	if (RT_FAILURE(rc))
272	pvObj = NULL;
273	}
274
275	/*
276	* Link it into the free list.
277	*/
278	if (pvObj)
279	{
280	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
281	RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
282
283	uint32_t const i = h - pThis->uBase;
284	if (pThis->iFreeTail == NIL_RTHT_INDEX)
285	pThis->iFreeHead = pThis->iFreeTail = i;
286	else
287	{
288	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
289	Assert(pPrev);
290	RTHT_SET_FREE_IDX(pPrev, i);
291	pThis->iFreeTail = i;
292	}
293
294	Assert(pThis->cCurAllocated > 0);
295	pThis->cCurAllocated--;
296	}
297	}
298	else
299	pvObj = NULL;
300	}
301
302	/* release the lock */
303	rtHandleTableUnlock(pThis, &Tmp);
304	return pvObj;
305	}
306	RT_EXPORT_SYMBOL(RTHandleTableFree);
307

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source: vbox/trunk/src/VBox/Runtime/common/misc/handletablesimple.cpp@ 34497

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