From f8fe689a81f906d1b91bb3220acde2a4ecb14c5b Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 05:01:46 +0200 Subject: Adding upstream version 6.0.4-dfsg. Signed-off-by: Daniel Baumann --- src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h | 208 +++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h (limited to 'src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h') diff --git a/src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h b/src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h new file mode 100644 index 00000000..4266b1b8 --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/ds/nsRecyclingAllocator.h @@ -0,0 +1,208 @@ +/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is mozilla.org code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 2001, 2002 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Suresh Duddi + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +/* + * nsRecyclingAllocator + * + * This allocator is useful when we cycle through a small set of allocations + * repeatedly with minimal overlap. For eg. something we do for every gif + * file read (or) buffers required for decompression of every file from jar. + * + * What this does is keeps around the first set of memory allocated and + * reuses it subsequently. If all buckets are full, this falls back to + * malloc/free + * + * Uses a timer to release all memory allocated if not used for more than + * 10 secs automatically. + * + * Also there is a 4 byte maintenance overhead on every allocation. + * + * This allocator is thread safe. + * + * CAVEATS: As the number of buckets increases, this allocators performance + * will drop. As a general guideline, dont use this for more + * than NS_MAX_BLOCKS + */ + +#ifndef nsRecyclingAllocator_h__ +#define nsRecyclingAllocator_h__ + +#include "nscore.h" +#include "pratom.h" +#include "prlock.h" +#include "nsIRecyclingAllocator.h" +#include "nsIGenericFactory.h" + +#define NS_DEFAULT_RECYCLE_TIMEOUT 10 // secs +#define NS_MAX_BLOCKS 24 +#define NS_ALLOCATOR_OVERHEAD_BYTES (sizeof(Block)) // bytes + +class nsITimer; +class nsIMemory; + +class NS_COM nsRecyclingAllocator { + protected: + struct Block { + PRSize bytes; + }; + + // Make |BlockStoreNode| a |friend| so it can access |Block|. + struct BlockStoreNode; + friend struct BlockStoreNode; + + struct BlockStoreNode { + BlockStoreNode() : bytes(0), block(nsnull), next(nsnull) {}; + PRSize bytes; + Block *block; + BlockStoreNode *next; + }; + +#define DATA(block) ((void *)(((char *)block) + NS_ALLOCATOR_OVERHEAD_BYTES)) +#define DATA_TO_BLOCK(data) ((Block *)((char *)(data) - NS_ALLOCATOR_OVERHEAD_BYTES)) + + // mMaxBlocks: Maximum number of blocks that can be allocated + PRUint32 mMaxBlocks; + + // mBlocks: + // All blocks used or not. + BlockStoreNode *mBlocks; + + // mFreeList + // A linked list of free blocks sorted by increasing order of size + BlockStoreNode* mFreeList; + + // mNotUsedList + // A linked list of BlockStoreNodes that are not used to store + // any block information. When we add blocks into mFreeList, we + // take BlockStoreNode from here. + BlockStoreNode* mNotUsedList; + + // mLock: Thread safety of mFreeList and mNotUsedList + PRLock *mLock; + + // Timer for freeing unused memory + nsITimer *mRecycleTimer; + + // mRecycleAfter: + // Allocator should be untouched for this many seconds for freeing + // unused Blocks. + PRUint32 mRecycleAfter; + + // mTouched: + // says if the allocator touched any bucket. If allocator didn't touch + // any bucket over a time time interval, timer will call FreeUnusedBuckets() + PRInt32 mTouched; + + // mId: + // a string for identifying the user of nsRecyclingAllocator + // User mainly for debug prints + const char *mId; + +#ifdef DEBUG + // mNAllocated: Number of blocks allocated + PRInt32 mNAllocated; +#endif + + public: + + // nbucket : number of buckets to hold. Capped at NS_MAX_BUCKET + // recycleAfter : Try recycling allocated buckets after this many seconds + // id : a string used to identify debug prints. Will not be released. + nsRecyclingAllocator(PRUint32 nbucket = 0, PRUint32 recycleAfter = NS_DEFAULT_RECYCLE_TIMEOUT, + const char *id = NULL); + ~nsRecyclingAllocator(); + + nsresult Init(PRUint32 nbucket, PRUint32 recycleAfter, const char *id); + + // Allocation and free routines + void* Malloc(PRSize size, PRBool zeroit = PR_FALSE); + void Free(void *ptr); + + void* Calloc(PRUint32 items, PRSize size) + { + return Malloc(items * size, PR_TRUE); + } + + // FreeUnusedBuckets - Frees any bucket memory that isn't in use + void FreeUnusedBuckets(); + + protected: + + // Timer callback to trigger unused memory + static void nsRecycleTimerCallback(nsITimer *aTimer, void *aClosure); + + // Freelist management + // FindFreeBlock: return a free block that can hold bytes (best fit) + Block* FindFreeBlock(PRSize bytes); + // AddToFreeList: adds block into our freelist for future retrieval. + // Returns PR_TRUE is addition was successful. PR_FALSE otherewise. + PRBool AddToFreeList(Block* block); + + // Touch will mark that someone used this allocator + // Timer based release will free unused memory only if allocator + // was not touched for mRecycleAfter seconds. + void Touch() { + if (!mTouched) + PR_AtomicSet(&mTouched, 1); + } + void Untouch() { + PR_AtomicSet(&mTouched, 0); + } + + friend void nsRecycleTimerCallback(nsITimer *aTimer, void *aClosure); +}; + +// ---------------------------------------------------------------------- +// Wrapping the recyling allocator with nsIMemory +// ---------------------------------------------------------------------- + +// Wrapping the nsRecyclingAllocator with nsIMemory +class nsRecyclingAllocatorImpl : public nsRecyclingAllocator, public nsIRecyclingAllocator { +public: + NS_DECL_ISUPPORTS + NS_DECL_NSIMEMORY + NS_DECL_NSIRECYCLINGALLOCATOR + + nsRecyclingAllocatorImpl() + { + } + +private: + ~nsRecyclingAllocatorImpl() {} +}; +#endif // nsRecyclingAllocator_h__ -- cgit v1.2.3