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Diffstat (limited to 'src/VBox/Runtime/common/misc/handletable.h')
| -rw-r--r-- | src/VBox/Runtime/common/misc/handletable.h | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/misc/handletable.h b/src/VBox/Runtime/common/misc/handletable.h new file mode 100644 index 00000000..7ae0c38a --- /dev/null +++ b/src/VBox/Runtime/common/misc/handletable.h @@ -0,0 +1,257 @@ +/* $Id: handletable.h $ */ +/** @file + * IPRT - Handle Tables, internal header. + */ + +/* + * Copyright (C) 2008-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + +#ifndef IPRT_INCLUDED_SRC_common_misc_handletable_h +#define IPRT_INCLUDED_SRC_common_misc_handletable_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + + +/******************************************************************************* +* Defined Constants And Macros * +*******************************************************************************/ +/** The number of entries in the 2nd level lookup table. */ +#define RTHT_LEVEL2_ENTRIES 2048 + +/** The number of (max) 1st level entries requiring dynamic allocation of the + * 1st level table. If the max number is below this threshold, the 1st level + * table will be allocated as part of the handle table structure. */ +#define RTHT_LEVEL1_DYN_ALLOC_THRESHOLD 256 + +/** Checks whether a object pointer is really a free entry or not. */ +#define RTHT_IS_FREE(pvObj) ( ((uintptr_t)(pvObj) & 3) == 3 ) + +/** Sets RTHTENTRYFREE::iNext. */ +#define RTHT_SET_FREE_IDX(pFree, idx) \ + do { \ + (pFree)->iNext = ((uintptr_t)((uint32_t)(idx)) << 2) | 3U; \ + } while (0) + +/** Gets the index part of RTHTENTRYFREE::iNext. */ +#define RTHT_GET_FREE_IDX(pFree) ( (uint32_t)((pFree)->iNext >> 2) ) + +/** @def NIL_RTHT_INDEX + * The NIL handle index for use in the free list. (The difference between + * 32-bit and 64-bit hosts here comes down to the shifting performed for + * RTHTENTRYFREE::iNext.) */ +#if ARCH_BITS == 32 +# define NIL_RTHT_INDEX ( UINT32_C(0x3fffffff) ) +#elif ARCH_BITS >= 34 +# define NIL_RTHT_INDEX ( UINT32_C(0xffffffff) ) +#else +# error "Missing or unsupported ARCH_BITS." +#endif + + +/******************************************************************************* +* Structures and Typedefs * +*******************************************************************************/ + +/** + * Handle table entry, simple variant. + */ +typedef struct RTHTENTRY +{ + /** The object. */ + void *pvObj; +} RTHTENTRY; +/** Pointer to a handle table entry, simple variant. */ +typedef RTHTENTRY *PRTHTENTRY; + + +/** + * Handle table entry, context variant. + */ +typedef struct RTHTENTRYCTX +{ + /** The object. */ + void *pvObj; + /** The context. */ + void *pvCtx; +} RTHTENTRYCTX; +/** Pointer to a handle table entry, context variant. */ +typedef RTHTENTRYCTX *PRTHTENTRYCTX; + + +/** + * Free handle table entry, shared by all variants. + */ +typedef struct RTHTENTRYFREE +{ + /** The index of the next handle, special format. + * In order to distinguish free and used handle table entries we exploit + * the heap alignment and use the lower two bits to do this. Used entries + * will have these bits set to 0, while free entries will have tem set + * to 3. Use the RTHT_GET_FREE_IDX and RTHT_SET_FREE_IDX macros to access + * this field. */ + uintptr_t iNext; +} RTHTENTRYFREE; +/** Pointer to a free handle table entry. */ +typedef RTHTENTRYFREE *PRTHTENTRYFREE; + +AssertCompile(sizeof(RTHTENTRYFREE) <= sizeof(RTHTENTRY)); +AssertCompile(sizeof(RTHTENTRYFREE) <= sizeof(RTHTENTRYCTX)); +AssertCompileMemberOffset(RTHTENTRYFREE, iNext, 0); +AssertCompileMemberOffset(RTHTENTRY, pvObj, 0); +AssertCompileMemberOffset(RTHTENTRYCTX, pvObj, 0); + + +/** + * Internal handle table structure. + */ +typedef struct RTHANDLETABLEINT +{ + /** Magic value (RTHANDLETABLE_MAGIC). */ + uint32_t u32Magic; + /** The handle table flags specified to RTHandleTableCreateEx. */ + uint32_t fFlags; + /** The base handle value (i.e. the first handle). */ + uint32_t uBase; + /** The current number of handle table entries. */ + uint32_t cCur; + /** The spinlock handle (NIL if RTHANDLETABLE_FLAGS_LOCKED wasn't used). */ + RTSPINLOCK hSpinlock; + /** The level one lookup table. */ + void **papvLevel1; + /** The retainer callback. Can be NULL. */ + PFNRTHANDLETABLERETAIN pfnRetain; + /** The user argument to the retainer. */ + void *pvRetainUser; + /** The max number of handles. */ + uint32_t cMax; + /** The number of handles currently allocated. (for optimizing destruction) */ + uint32_t cCurAllocated; + /** The current number of 1st level entries. */ + uint32_t cLevel1; + /** Head of the list of free handle entires (index). */ + uint32_t iFreeHead; + /** Tail of the list of free handle entires (index). */ + uint32_t iFreeTail; +} RTHANDLETABLEINT; +/** Pointer to an handle table structure. */ +typedef RTHANDLETABLEINT *PRTHANDLETABLEINT; + + +/** + * Looks up a simple index. + * + * @returns Pointer to the handle table entry on success, NULL on failure. + * @param pThis The handle table structure. + * @param i The index to look up. + */ +DECLINLINE(PRTHTENTRY) rtHandleTableLookupSimpleIdx(PRTHANDLETABLEINT pThis, uint32_t i) +{ + if (i < pThis->cCur) + { + PRTHTENTRY paTable = (PRTHTENTRY)pThis->papvLevel1[i / RTHT_LEVEL2_ENTRIES]; + if (paTable) + return &paTable[i % RTHT_LEVEL2_ENTRIES]; + } + return NULL; +} + + +/** + * Looks up a simple handle. + * + * @returns Pointer to the handle table entry on success, NULL on failure. + * @param pThis The handle table structure. + * @param h The handle to look up. + */ +DECLINLINE(PRTHTENTRY) rtHandleTableLookupSimple(PRTHANDLETABLEINT pThis, uint32_t h) +{ + return rtHandleTableLookupSimpleIdx(pThis, h - pThis->uBase); +} + + +/** + * Looks up a context index. + * + * @returns Pointer to the handle table entry on success, NULL on failure. + * @param pThis The handle table structure. + * @param i The index to look up. + */ +DECLINLINE(PRTHTENTRYCTX) rtHandleTableLookupWithCtxIdx(PRTHANDLETABLEINT pThis, uint32_t i) +{ + if (i < pThis->cCur) + { + PRTHTENTRYCTX paTable = (PRTHTENTRYCTX)pThis->papvLevel1[i / RTHT_LEVEL2_ENTRIES]; + if (paTable) + return &paTable[i % RTHT_LEVEL2_ENTRIES]; + } + return NULL; +} + + +/** + * Looks up a context handle. + * + * @returns Pointer to the handle table entry on success, NULL on failure. + * @param pThis The handle table structure. + * @param h The handle to look up. + */ +DECLINLINE(PRTHTENTRYCTX) rtHandleTableLookupWithCtx(PRTHANDLETABLEINT pThis, uint32_t h) +{ + return rtHandleTableLookupWithCtxIdx(pThis, h - pThis->uBase); +} + + +/** + * Locks the handle table. + * + * @param pThis The handle table structure. + */ +DECLINLINE(void) rtHandleTableLock(PRTHANDLETABLEINT pThis) +{ + if (pThis->hSpinlock != NIL_RTSPINLOCK) + RTSpinlockAcquire(pThis->hSpinlock); +} + + +/** + * Locks the handle table. + * + * @param pThis The handle table structure. + */ +DECLINLINE(void) rtHandleTableUnlock(PRTHANDLETABLEINT pThis) +{ + if (pThis->hSpinlock != NIL_RTSPINLOCK) + RTSpinlockRelease(pThis->hSpinlock); +} + +#endif /* !IPRT_INCLUDED_SRC_common_misc_handletable_h */ + |