handletable.cpp@ 10788

Last change on this file since 10788 was 10788, checked in by vboxsync, 16 years ago
IPRT: Implemented the context variant of the handle table.
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1	/* $Id: handletable.cpp 10788 2008-07-21 16:44:33Z vboxsync $ */
2	/** @file
3	* IPRT - Handle Tables.
4	*/
5
6	/*
7	* Copyright (C) 2008 Sun Microsystems, Inc.
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	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*******************************************************************************
32	* Header Files *
33	*******************************************************************************/
34	#include <iprt/handletable.h>
35	#include <iprt/mem.h>
36	#include <iprt/spinlock.h>
37	#include <iprt/err.h>
38	#include <iprt/assert.h>
39	#include <iprt/param.h>
40	#include <iprt/string.h>
41	#include <iprt/asm.h>
42	#include "internal/magics.h"
43
44
45	/*******************************************************************************
46	* Defined Constants And Macros *
47	*******************************************************************************/
48	/** The number of entries in the 2nd level lookup table. */
49	#define RTHT_LEVEL2_ENTRIES 2048
50
51	/** The number of (max) 1st level entries requiring dynamic allocation of the
52	* 1st level table. If the max number is below this threshold, the 1st level
53	* table will be allocated as part of the handle table structure. */
54	#define RTHT_LEVEL1_DYN_ALLOC_THRESHOLD 256
55
56	/** Checks whether a object pointer is really a free entry or not. */
57	#define RTHT_IS_FREE(pvObj) ( ((uintptr_t)(pvObj) & 3) == 3 )
58
59	/** Sets RTHTENTRYFREE::iNext. */
60	#define RTHT_SET_FREE_IDX(pFree, idx) \
61	do { \
62	(pFree)->iNext = ((uintptr_t)((uint32_t)(idx)) << 2) \| 3U; \
63	} while (0)
64
65	/** Gets the index part of RTHTENTRYFREE::iNext. */
66	#define RTHT_GET_FREE_IDX(pFree) ( (uint32_t)((pFree)->iNext >> 2) )
67
68	/** @def NIL_RTHT_INDEX
69	* The NIL handle index for use in the free list. (The difference between
70	* 32-bit and 64-bit hosts here comes down to the shifting performed for
71	* RTHTENTRYFREE::iNext.) */
72	#if ARCH_BITS == 32
73	# define NIL_RTHT_INDEX ( UINT32_C(0x3fffffff) )
74	#elif ARCH_BITS >= 34
75	# define NIL_RTHT_INDEX ( UINT32_C(0xffffffff) )
76	#else
77	# error "Missing or unsupported ARCH_BITS."
78	#endif
79
80
81	/*******************************************************************************
82	* Structures and Typedefs *
83	*******************************************************************************/
84
85	/**
86	* Handle table entry, simple variant.
87	*/
88	typedef struct RTHTENTRY
89	{
90	/** The object. */
91	void *pvObj;
92	} RTHTENTRY;
93	/** Pointer to a handle table entry, simple variant. */
94	typedef RTHTENTRY *PRTHTENTRY;
95
96
97	/**
98	* Handle table entry, context variant.
99	*/
100	typedef struct RTHTENTRYCTX
101	{
102	/** The object. */
103	void *pvObj;
104	/** The context. */
105	void *pvCtx;
106	} RTHTENTRYCTX;
107	/** Pointer to a handle table entry, context variant. */
108	typedef RTHTENTRYCTX *PRTHTENTRYCTX;
109
110
111	/**
112	* Free handle table entry, shared by all variants.
113	*/
114	typedef struct RTHTENTRYFREE
115	{
116	/** The index of the next handle, special format.
117	* In order to distinguish free and used handle table entries we exploit
118	* the heap alignment and use the lower two bits to do this. Used entries
119	* will have these bits set to 0, while free entries will have tem set
120	* to 3. Use the RTHT_GET_FREE_IDX and RTHT_SET_FREE_IDX macros to access
121	* this field. */
122	uintptr_t iNext;
123	} RTHTENTRYFREE;
124	/** Pointer to a free handle table entry. */
125	typedef RTHTENTRYFREE *PRTHTENTRYFREE;
126
127	AssertCompile(sizeof(RTHTENTRYFREE) <= sizeof(RTHTENTRY));
128	AssertCompile(sizeof(RTHTENTRYFREE) <= sizeof(RTHTENTRYCTX));
129	AssertCompileMemberOffset(RTHTENTRYFREE, iNext, 0);
130	AssertCompileMemberOffset(RTHTENTRY, pvObj, 0);
131	AssertCompileMemberOffset(RTHTENTRYCTX, pvObj, 0);
132
133
134	/**
135	* Internal handle table structure.
136	*/
137	typedef struct RTHANDLETABLEINT
138	{
139	/** Magic value (RTHANDLETABLE_MAGIC). */
140	uint32_t u32Magic;
141	/** The handle table flags specified to RTHandleTableCreateEx. */
142	uint32_t fFlags;
143	/** The base handle value (i.e. the first handle). */
144	uint32_t uBase;
145	/** The current number of handle table entries. */
146	uint32_t cCur;
147	/** The spinlock handle (NIL if RTHANDLETABLE_FLAGS_LOCKED wasn't used). */
148	RTSPINLOCK hSpinlock;
149	/** The level one lookup table. */
150	void **papvLevel1;
151	/** The retainer callback. Can be NULL. */
152	PFNRTHANDLETABLERETAIN pfnRetain;
153	/** The user argument to the retainer. */
154	void *pvRetainUser;
155	/** The max number of handles. */
156	uint32_t cMax;
157	/** The number of handles currently allocated. (for optimizing destruction) */
158	uint32_t cCurAllocated;
159	/** The current number of 1st level entries. */
160	uint32_t cLevel1;
161	/** Head of the list of free handle entires (index). */
162	uint32_t iFreeHead;
163	/** Tail of the list of free handle entires (index). */
164	uint32_t iFreeTail;
165	} RTHANDLETABLEINT;
166	/** Pointer to an handle table structure. */
167	typedef RTHANDLETABLEINT *PRTHANDLETABLEINT;
168
169
170	/**
171	* Looks up a simple index.
172	*
173	* @returns Pointer to the handle table entry on success, NULL on failure.
174	* @param pThis The handle table structure.
175	* @param i The index to look up.
176	*/
177	DECLINLINE(PRTHTENTRY) rtHandleTableLookupSimpleIdx(PRTHANDLETABLEINT pThis, uint32_t i)
178	{
179	if (i < pThis->cCur)
180	{
181	PRTHTENTRY paTable = (PRTHTENTRY)pThis->papvLevel1[i / RTHT_LEVEL2_ENTRIES];
182	if (paTable)
183	return &paTable[i % RTHT_LEVEL2_ENTRIES];
184	}
185	return NULL;
186	}
187
188
189	/**
190	* Looks up a simple handle.
191	*
192	* @returns Pointer to the handle table entry on success, NULL on failure.
193	* @param pThis The handle table structure.
194	* @param h The handle to look up.
195	*/
196	DECLINLINE(PRTHTENTRY) rtHandleTableLookupSimple(PRTHANDLETABLEINT pThis, uint32_t h)
197	{
198	return rtHandleTableLookupSimpleIdx(pThis, h - pThis->uBase);
199	}
200
201
202	/**
203	* Looks up a context index.
204	*
205	* @returns Pointer to the handle table entry on success, NULL on failure.
206	* @param pThis The handle table structure.
207	* @param i The index to look up.
208	*/
209	DECLINLINE(PRTHTENTRYCTX) rtHandleTableLookupWithCtxIdx(PRTHANDLETABLEINT pThis, uint32_t i)
210	{
211	if (i < pThis->cCur)
212	{
213	PRTHTENTRYCTX paTable = (PRTHTENTRYCTX)pThis->papvLevel1[i / RTHT_LEVEL2_ENTRIES];
214	if (paTable)
215	return &paTable[i % RTHT_LEVEL2_ENTRIES];
216	}
217	return NULL;
218	}
219
220
221	/**
222	* Looks up a context handle.
223	*
224	* @returns Pointer to the handle table entry on success, NULL on failure.
225	* @param pThis The handle table structure.
226	* @param h The handle to look up.
227	*/
228	DECLINLINE(PRTHTENTRYCTX) rtHandleTableLookupWithCtx(PRTHANDLETABLEINT pThis, uint32_t h)
229	{
230	return rtHandleTableLookupWithCtxIdx(pThis, h - pThis->uBase);
231	}
232
233
234	/**
235	* Locks the handle table.
236	*
237	* @param pThis The handle table structure.
238	* @param pTmp The spinlock temp variable.
239	*/
240	DECLINLINE(void) rtHandleTableLock(PRTHANDLETABLEINT pThis, PRTSPINLOCKTMP pTmp)
241	{
242	if (pThis->hSpinlock != NIL_RTSPINLOCK)
243	{
244	RTSPINLOCKTMP const Tmp = RTSPINLOCKTMP_INITIALIZER;
245	*pTmp = Tmp;
246	RTSpinlockAcquire(pThis->hSpinlock, pTmp);
247	}
248	}
249
250
251	/**
252	* Locks the handle table.
253	*
254	* @param pThis The handle table structure.
255	* @param pTmp The spinlock temp variable.
256	*/
257	DECLINLINE(void) rtHandleTableUnlock(PRTHANDLETABLEINT pThis, PRTSPINLOCKTMP pTmp)
258	{
259	if (pThis->hSpinlock != NIL_RTSPINLOCK)
260	RTSpinlockRelease(pThis->hSpinlock, pTmp);
261	}
262
263
264	RTDECL(int) RTHandleTableCreateEx(PRTHANDLETABLE phHandleTable, uint32_t fFlags, uint32_t uBase, uint32_t cMax,
265	PFNRTHANDLETABLERETAIN pfnRetain, void *pvUser)
266	{
267	/*
268	* Validate input.
269	*/
270	AssertPtrReturn(phHandleTable, VERR_INVALID_POINTER);
271	*phHandleTable = NIL_RTHANDLETABLE;
272	AssertPtrNullReturn(pfnRetain, VERR_INVALID_POINTER);
273	AssertReturn(!(fFlags & ~RTHANDLETABLE_FLAGS_MASK), VERR_INVALID_PARAMETER);
274	AssertReturn(cMax > 0, VERR_INVALID_PARAMETER);
275	AssertReturn(UINT32_MAX - cMax >= uBase, VERR_INVALID_PARAMETER);
276
277	/*
278	* Adjust the cMax value so it is a multiple of the 2nd level tables.
279	*/
280	if (cMax >= UINT32_MAX - RTHT_LEVEL2_ENTRIES)
281	cMax = UINT32_MAX - RTHT_LEVEL2_ENTRIES + 1;
282	cMax = ((cMax + RTHT_LEVEL2_ENTRIES - 1) / RTHT_LEVEL2_ENTRIES) * RTHT_LEVEL2_ENTRIES;
283
284	uint32_t const cLevel1 = cMax / RTHT_LEVEL2_ENTRIES;
285	Assert(cLevel1 * RTHT_LEVEL2_ENTRIES == cMax);
286
287	/*
288	* Allocate the structure, include the 1st level lookup table
289	* if it's below the threshold size.
290	*/
291	size_t cb = sizeof(RTHANDLETABLEINT);
292	if (cLevel1 < RTHT_LEVEL1_DYN_ALLOC_THRESHOLD)
293	cb = RT_ALIGN(cb, sizeof(void )) + cLevel1 sizeof(void *);
294	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)RTMemAllocZ(cb);
295	if (!pThis)
296	return VERR_NO_MEMORY;
297
298	/*
299	* Initialize it.
300	*/
301	pThis->u32Magic = RTHANDLETABLE_MAGIC;
302	pThis->fFlags = fFlags;
303	pThis->uBase = uBase;
304	pThis->cCur = 0;
305	pThis->hSpinlock = NIL_RTSPINLOCK;
306	if (cLevel1 < RTHT_LEVEL1_DYN_ALLOC_THRESHOLD)
307	pThis->papvLevel1 = (void *)((uint8_t )pThis + RT_ALIGN(sizeof(pThis), sizeof(void )));
308	else
309	pThis->papvLevel1 = NULL;
310	pThis->pfnRetain = pfnRetain;
311	pThis->pvRetainUser = pvUser;
312	pThis->cMax = cMax;
313	pThis->cCurAllocated = 0;
314	pThis->cLevel1 = cLevel1 < RTHT_LEVEL1_DYN_ALLOC_THRESHOLD ? cLevel1 : 0;
315	pThis->iFreeHead = NIL_RTHT_INDEX;
316	pThis->iFreeTail = NIL_RTHT_INDEX;
317	if (fFlags & RTHANDLETABLE_FLAGS_LOCKED)
318	{
319	int rc = RTSpinlockCreate(&pThis->hSpinlock);
320	if (RT_FAILURE(rc))
321	{
322	RTMemFree(pThis);
323	return rc;
324	}
325	}
326
327	*phHandleTable = pThis;
328	return VINF_SUCCESS;
329	}
330
331
332	RTDECL(int) RTHandleTableCreate(PRTHANDLETABLE phHandleTable)
333	{
334	return RTHandleTableCreateEx(phHandleTable, RTHANDLETABLE_FLAGS_LOCKED, 1, 65534, NULL, NULL);
335	}
336
337
338	RTDECL(int) RTHandleTableDestroy(RTHANDLETABLE hHandleTable, PFNRTHANDLETABLEDELETE pfnDelete, void *pvUser)
339	{
340	/*
341	* Validate input, quitely ignore the NIL handle.
342	*/
343	if (hHandleTable == NIL_RTHANDLETABLE)
344	return VINF_SUCCESS;
345	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
346	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
347	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
348	AssertPtrNullReturn(pfnDelete, VERR_INVALID_POINTER);
349
350	/*
351	* Mark the thing as invalid / deleted.
352	* Then kill the lock.
353	*/
354	RTSPINLOCKTMP Tmp;
355	rtHandleTableLock(pThis, &Tmp);
356	ASMAtomicWriteU32(&pThis->u32Magic, ~RTHANDLETABLE_MAGIC);
357	rtHandleTableUnlock(pThis, &Tmp);
358
359	if (pThis->hSpinlock != NIL_RTSPINLOCK)
360	{
361	rtHandleTableLock(pThis, &Tmp);
362	rtHandleTableUnlock(pThis, &Tmp);
363
364	RTSpinlockDestroy(pThis->hSpinlock);
365	pThis->hSpinlock = NIL_RTSPINLOCK;
366	}
367
368	if (pfnDelete)
369	{
370	/*
371	* Walk all the tables looking for used handles.
372	*/
373	uint32_t cLeft = pThis->cCurAllocated;
374	if (pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT)
375	{
376	for (uint32_t i1 = 0; cLeft > 0 && i1 < pThis->cLevel1; i1++)
377	{
378	PRTHTENTRYCTX paTable = (PRTHTENTRYCTX)pThis->papvLevel1[i1];
379	if (paTable)
380	for (uint32_t i = 0; i < RTHT_LEVEL2_ENTRIES; i++)
381	if (!RTHT_IS_FREE(paTable[i].pvObj))
382	{
383	pfnDelete(hHandleTable, pThis->uBase + i + i1 * RTHT_LEVEL2_ENTRIES,
384	paTable[i].pvObj, paTable[i].pvCtx, pvUser);
385	Assert(cLeft > 0);
386	cLeft--;
387	}
388	}
389	}
390	else
391	{
392	for (uint32_t i1 = 0; cLeft > 0 && i1 < pThis->cLevel1; i1++)
393	{
394	PRTHTENTRY paTable = (PRTHTENTRY)pThis->papvLevel1[i1];
395	if (paTable)
396	for (uint32_t i = 0; i < RTHT_LEVEL2_ENTRIES; i++)
397	if (!RTHT_IS_FREE(paTable[i].pvObj))
398	{
399	pfnDelete(hHandleTable, pThis->uBase + i + i1 * RTHT_LEVEL2_ENTRIES,
400	paTable[i].pvObj, NULL, pvUser);
401	Assert(cLeft > 0);
402	cLeft--;
403	}
404	}
405	}
406	Assert(!cLeft);
407	}
408
409	/*
410	* Free the memory.
411	*/
412	for (uint32_t i1 = 0; i1 < pThis->cLevel1; i1++)
413	if (pThis->papvLevel1[i1])
414	{
415	RTMemFree(pThis->papvLevel1[i1]);
416	pThis->papvLevel1[i1] = NULL;
417	}
418
419	if (pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD)
420	RTMemFree(pThis->papvLevel1);
421
422	RTMemFree(pThis);
423
424	return VINF_SUCCESS;
425	}
426
427
428	/**
429	* Allocates a handle from the handle table.
430	*
431	* @returns IPRT status code, almost any.
432	* @retval VINF_SUCCESS on success.
433	* @retval VERR_NO_MEMORY if we failed to extend the handle table.
434	* @retval VERR_NO_MORE_HANDLES if we're out of handles.
435	*
436	* @param hHandleTable The handle to the handle table.
437	* @param pvObj The object to associate with the new handle.
438	* @param ph Where to return the handle on success.
439	*
440	* @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
441	*/
442	RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void pvObj, uint32_t ph);
443
444	/**
445	* Looks up a handle.
446	*
447	* @returns The object pointer on success. NULL on failure.
448	*
449	* @param hHandleTable The handle to the handle table.
450	* @param h The handle to lookup.
451	*
452	* @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
453	*/
454	RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h);
455
456	/**
457	* Looks up and frees a handle.
458	*
459	* @returns The object pointer on success. NULL on failure.
460	*
461	* @param hHandleTable The handle to the handle table.
462	* @param h The handle to lookup.
463	*
464	* @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
465	*/
466	RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h);
467
468
469	RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void pvObj, void pvCtx, uint32_t *ph)
470	{
471	/* validate the input */
472	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
473	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
474	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
475	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, VERR_INVALID_FUNCTION);
476	AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
477	AssertPtrReturn(ph, VERR_INVALID_POINTER);
478	*ph = pThis->uBase - 1;
479
480	/*
481	* Allocation loop.
482	*/
483	RTSPINLOCKTMP Tmp;
484	rtHandleTableLock(pThis, &Tmp);
485
486	int rc;
487	do
488	{
489	/*
490	* Try grab a free entry from the head of the free list.
491	*/
492	uint32_t i = pThis->iFreeHead;
493	if (i != NIL_RTHT_INDEX)
494	{
495	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, i);
496	Assert(pFree);
497	if (i == pThis->iFreeTail)
498	pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
499	else
500	pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
501	pThis->cCurAllocated++;
502	Assert(pThis->cCurAllocated <= pThis->cCur);
503
504	/*
505	* Setup the entry and return.
506	*/
507	PRTHTENTRYCTX pEntry = (PRTHTENTRYCTX)pFree;
508	pEntry->pvObj = pvObj;
509	pEntry->pvCtx = pvCtx;
510	*ph = i + pThis->uBase;
511	rc = VINF_SUCCESS;
512	}
513	/*
514	* Must expand the handle table, unless it's full.
515	*/
516	else if (pThis->cCur >= pThis->cMax)
517	{
518	rc = VERR_NO_MORE_HANDLES;
519	Assert(pThis->cCur == pThis->cCurAllocated);
520	}
521	else
522	{
523	/*
524	* Do we have to expand the 1st level table too?
525	*/
526	uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
527	uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
528	? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
529	: 0;
530	if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
531	cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
532	Assert(!cLevel1 \|\| pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
533
534	/* leave the lock (never do fancy stuff from behind a spinlock). */
535	rtHandleTableUnlock(pThis, &Tmp);
536
537	/*
538	* Do the allocation(s).
539	*/
540	rc = VERR_TRY_AGAIN;
541	void **papvLevel1 = NULL;
542	if (cLevel1)
543	{
544	papvLevel1 = (void *)RTMemAlloc(sizeof(void ) * cLevel1);
545	if (!papvLevel1)
546	return VERR_NO_MEMORY;
547	}
548
549	PRTHTENTRYCTX paTable = (PRTHTENTRYCTX)RTMemAlloc(sizeof(paTable) RTHT_LEVEL2_ENTRIES);
550	if (!paTable)
551	{
552	RTMemFree(papvLevel1);
553	return VERR_NO_MEMORY;
554	}
555
556	/* re-enter the lock. */
557	rtHandleTableLock(pThis, &Tmp);
558
559	/*
560	* Insert the new bits, but be a bit careful as someone might have
561	* raced us expanding the table.
562	*/
563	/* deal with the 1st level lookup expansion first */
564	if (cLevel1)
565	{
566	Assert(papvLevel1);
567	if (cLevel1 > pThis->cLevel1)
568	{
569	/* Replace the 1st level table. */
570	memcpy(papvLevel1, pThis->papvLevel1, sizeof(void ) pThis->cLevel1);
571	memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void ) (cLevel1 - pThis->cLevel1));
572	pThis->cLevel1 = cLevel1;
573	void **papvTmp = pThis->papvLevel1;
574	pThis->papvLevel1 = papvLevel1;
575	papvLevel1 = papvTmp;
576	}
577
578	/* free the obsolete one (outside the lock of course) */
579	rtHandleTableUnlock(pThis, &Tmp);
580	RTMemFree(papvLevel1);
581	rtHandleTableLock(pThis, &Tmp);
582	}
583
584	/* insert the table we allocated */
585	if (pThis->cCur < pThis->cMax)
586	{
587	uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
588	pThis->papvLevel1[iLevel1New] = paTable;
589
590	/* link all entries into a free list. */
591	Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
592	for (uint32_t i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
593	{
594	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
595	paTable[i].pvCtx = (void *)~(uintptr_t)7;
596	}
597	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
598	paTable[RTHT_LEVEL2_ENTRIES - 1].pvCtx = (void *)~(uintptr_t)7;
599
600	/* join the free list with the other. */
601	if (pThis->iFreeTail == NIL_RTHT_INDEX)
602	pThis->iFreeHead = pThis->cCur;
603	else
604	{
605	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, pThis->iFreeTail);
606	Assert(pPrev);
607	RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
608	}
609	pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
610
611	pThis->cCur += RTHT_LEVEL2_ENTRIES;
612	}
613	else
614	{
615	/* free the table (raced someone, and we lost). */
616	rtHandleTableUnlock(pThis, &Tmp);
617	RTMemFree(paTable);
618	rtHandleTableLock(pThis, &Tmp);
619	}
620
621	rc = VERR_TRY_AGAIN;
622	}
623	} while (rc == VERR_TRY_AGAIN);
624
625	rtHandleTableUnlock(pThis, &Tmp);
626
627	return rc;
628	}
629
630
631	RTDECL(void ) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void pvCtx)
632	{
633	/* validate the input */
634	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
635	AssertPtrReturn(pThis, NULL);
636	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
637	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, NULL);
638
639	void *pvObj = NULL;
640
641	/* acquire the lock */
642	RTSPINLOCKTMP Tmp;
643	rtHandleTableLock(pThis, &Tmp);
644
645	/*
646	* Perform the lookup and retaining.
647	*/
648	PRTHTENTRYCTX pEntry = rtHandleTableLookupWithCtx(pThis, h);
649	if (pEntry && pEntry->pvCtx == pvCtx)
650	{
651	pvObj = pEntry->pvObj;
652	if (!RTHT_IS_FREE(pvObj))
653	{
654	if (pThis->pfnRetain)
655	{
656	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, pvCtx, pThis->pvRetainUser);
657	if (RT_FAILURE(rc))
658	pvObj = NULL;
659	}
660	}
661	else
662	pvObj = NULL;
663	}
664
665	/* release the lock */
666	rtHandleTableUnlock(pThis, &Tmp);
667	return pvObj;
668	}
669
670
671	RTDECL(void ) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void pvCtx)
672	{
673	/* validate the input */
674	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
675	AssertPtrReturn(pThis, NULL);
676	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
677	AssertReturn(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT, NULL);
678
679	void *pvObj = NULL;
680
681	/* acquire the lock */
682	RTSPINLOCKTMP Tmp;
683	rtHandleTableLock(pThis, &Tmp);
684
685	/*
686	* Perform the lookup and retaining.
687	*/
688	PRTHTENTRYCTX pEntry = rtHandleTableLookupWithCtx(pThis, h);
689	if (pEntry && pEntry->pvCtx == pvCtx)
690	{
691	pvObj = pEntry->pvObj;
692	if (!RTHT_IS_FREE(pvObj))
693	{
694	if (pThis->pfnRetain)
695	{
696	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, pvCtx, pThis->pvRetainUser);
697	if (RT_FAILURE(rc))
698	pvObj = NULL;
699	}
700
701	/*
702	* Link it into the free list.
703	*/
704	if (pvObj)
705	{
706	pEntry->pvCtx = (void *)~(uintptr_t)7;
707
708	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
709	RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
710
711	uint32_t const i = h - pThis->uBase;
712	if (pThis->iFreeTail == NIL_RTHT_INDEX)
713	pThis->iFreeHead = pThis->iFreeTail = i;
714	else
715	{
716	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupWithCtxIdx(pThis, pThis->iFreeTail);
717	Assert(pPrev);
718	RTHT_SET_FREE_IDX(pPrev, i);
719	pThis->iFreeTail = i;
720	}
721
722	Assert(pThis->cCurAllocated > 0);
723	pThis->cCurAllocated--;
724	}
725	}
726	else
727	pvObj = NULL;
728	}
729
730	/* release the lock */
731	rtHandleTableUnlock(pThis, &Tmp);
732	return pvObj;
733	}
734

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source: vbox/trunk/src/VBox/Runtime/common/misc/handletable.cpp@ 10788

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