550 lines
15 KiB
C++
550 lines
15 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* The contents of this file are subject to the Mozilla Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* rights and limitations under the License.
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*
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* The Original Code is nsMemoryCacheDevice.cpp, released February 22, 2001.
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*
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* The Initial Developer of the Original Code is Netscape Communications
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* Corporation. Portions created by Netscape are
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* Copyright (C) 2001 Netscape Communications Corporation. All
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* Rights Reserved.
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*
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* Contributor(s):
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* Gordon Sheridan, <gordon@netscape.com>
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* Patrick C. Beard <beard@netscape.com>
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* Brian Ryner <bryner@netscape.com>
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*/
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#include "nsMemoryCacheDevice.h"
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#include "nsCacheService.h"
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#include "nsICacheService.h"
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#include "nsIStorageStream.h"
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#include "nsICacheVisitor.h"
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#include "nsCRT.h"
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// The memory cache implements the "LRU-SP" caching algorithm described in
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// "LRU-SP: A Size-Adjusted and Popularity-Aware LRU Replacement Algorithm
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// for Web Caching" by Kai Cheng and Yahiko Kambayashi.
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// We keep ceil(log2(mHardLimit+1)) LRU queues. The queues hold exponentially
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// increasing ranges of floor(log2((size/nref))) values for entries.
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const char *gMemoryDeviceID = "memory";
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nsMemoryCacheDevice::nsMemoryCacheDevice()
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: mInitialized(PR_FALSE),
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mEvictionList(nsnull),
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mEvictionThreshold(40 * 1024),
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mHardLimit(4 * 1024 * 1024), // set default memory limit, in case prefs aren't available
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mTotalSize(0),
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mInactiveSize(0),
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mEntryCount(0),
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mMaxEntryCount(0),
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mQueueCount(0)
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{
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// mEvictionList is created lazily to avoid re-creating it if the
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// capacity is set immediately.
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}
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nsMemoryCacheDevice::~nsMemoryCacheDevice()
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{
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Shutdown();
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}
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nsresult
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nsMemoryCacheDevice::Init()
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{
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if (mInitialized) return NS_ERROR_ALREADY_INITIALIZED;
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nsresult rv = mMemCacheEntries.Init();
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// set some default memory limits, in case prefs aren't available
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mSoftLimit = (mHardLimit * 9) / 10;
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mInitialized = NS_SUCCEEDED(rv);
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return rv;
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}
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nsresult
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nsMemoryCacheDevice::Shutdown()
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{
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NS_ASSERTION(mInitialized, "### attempting to shutdown while not initialized.\n");
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NS_ENSURE_TRUE(mInitialized, NS_ERROR_NOT_INITIALIZED);
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mMemCacheEntries.Shutdown();
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// evict all entries
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nsCacheEntry * entry, * next;
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for (int i = mQueueCount - 1; i >= 0; --i) {
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entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
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while (entry != &mEvictionList[i]) {
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NS_ASSERTION(entry->IsInUse() == PR_FALSE, "### shutting down with active entries.\n");
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next = (nsCacheEntry *)PR_NEXT_LINK(entry);
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PR_REMOVE_AND_INIT_LINK(entry);
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// update statistics
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PRInt32 memoryRecovered = (PRInt32)entry->Size();
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mTotalSize -= memoryRecovered;
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mInactiveSize -= memoryRecovered;
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--mEntryCount;
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delete entry;
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entry = next;
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}
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}
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/*
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* we're not factoring in changes to meta data yet...
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* NS_ASSERTION(mTotalSize == 0, "### mem cache leaking entries?\n");
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*/
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NS_ASSERTION(mInactiveSize == 0, "### mem cache leaking entries?\n");
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NS_ASSERTION(mEntryCount == 0, "### mem cache leaking entries?\n");
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mInitialized = PR_FALSE;
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delete[] mEvictionList;
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mEvictionList = nsnull;
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return NS_OK;
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}
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const char *
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nsMemoryCacheDevice::GetDeviceID()
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{
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return gMemoryDeviceID;
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}
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nsCacheEntry *
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nsMemoryCacheDevice::FindEntry(nsCString * key)
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{
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nsCacheEntry * entry = mMemCacheEntries.GetEntry(key);
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if (!entry) return nsnull;
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// move entry to the tail of an eviction list
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PR_REMOVE_AND_INIT_LINK(entry);
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EnsureEvictionLists();
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PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, 0)]);
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mInactiveSize -= entry->Size();
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return entry;
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}
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nsresult
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nsMemoryCacheDevice::DeactivateEntry(nsCacheEntry * entry)
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{
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if (entry->IsDoomed()) {
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#if debug
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// XXX verify we've removed it from mMemCacheEntries & eviction list
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#endif
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// update statistics
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mTotalSize -= entry->Size();
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--mEntryCount;
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delete entry;
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return NS_OK;
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}
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nsCacheEntry * ourEntry = mMemCacheEntries.GetEntry(entry->Key());
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NS_ASSERTION(ourEntry, "DeactivateEntry called for an entry we don't have!");
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NS_ASSERTION(entry == ourEntry, "entry doesn't match ourEntry");
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if (ourEntry != entry)
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return NS_ERROR_INVALID_POINTER;
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mInactiveSize += entry->Size();
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EvictEntriesIfNecessary();
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return NS_OK;
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}
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nsresult
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nsMemoryCacheDevice::BindEntry(nsCacheEntry * entry)
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{
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if (!entry->IsDoomed()) {
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NS_ASSERTION(PR_CLIST_IS_EMPTY(entry),"entry is already on a list!");
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// append entry to the eviction list
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EnsureEvictionLists();
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PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, 0)]);
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// add entry to hashtable of mem cache entries
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nsresult rv = mMemCacheEntries.AddEntry(entry);
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if (NS_FAILED(rv)) {
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PR_REMOVE_AND_INIT_LINK(entry);
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return rv;
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}
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}
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// add size of entry to memory totals
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++mEntryCount;
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if (mMaxEntryCount < mEntryCount) mMaxEntryCount = mEntryCount;
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mTotalSize += entry->Size();
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EvictEntriesIfNecessary();
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return NS_OK;
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}
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void
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nsMemoryCacheDevice::DoomEntry(nsCacheEntry * entry)
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{
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// XXX debug code to verify we have entry
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mMemCacheEntries.RemoveEntry(entry);
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// remove entry from our eviction list
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PR_REMOVE_AND_INIT_LINK(entry);
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}
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nsresult
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nsMemoryCacheDevice::OpenInputStreamForEntry( nsCacheEntry * entry,
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nsCacheAccessMode mode,
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PRUint32 offset,
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nsIInputStream ** result)
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{
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NS_ENSURE_ARG_POINTER(entry);
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NS_ENSURE_ARG_POINTER(result);
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nsCOMPtr<nsISupports> data;
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nsCOMPtr<nsIStorageStream> storage;
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nsresult rv = entry->GetData(getter_AddRefs(data));
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if (NS_FAILED(rv))
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return rv;
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if (data) {
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storage = do_QueryInterface(data, &rv);
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if (NS_FAILED(rv))
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return rv;
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}
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else {
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rv = NS_NewStorageStream(4096, PRUint32(-1), getter_AddRefs(storage));
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if (NS_FAILED(rv))
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return rv;
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entry->SetData(storage);
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}
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return storage->NewInputStream(offset, result);
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}
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nsresult
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nsMemoryCacheDevice::OpenOutputStreamForEntry( nsCacheEntry * entry,
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nsCacheAccessMode mode,
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PRUint32 offset,
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nsIOutputStream ** result)
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{
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NS_ENSURE_ARG_POINTER(entry);
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NS_ENSURE_ARG_POINTER(result);
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nsCOMPtr<nsISupports> data;
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nsCOMPtr<nsIStorageStream> storage;
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nsresult rv = entry->GetData(getter_AddRefs(data));
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if (NS_FAILED(rv))
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return rv;
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if (data) {
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storage = do_QueryInterface(data, &rv);
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if (NS_FAILED(rv))
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return rv;
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}
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else {
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rv = NS_NewStorageStream(4096, PRUint32(-1), getter_AddRefs(storage));
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if (NS_FAILED(rv))
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return rv;
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entry->SetData(storage);
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}
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return storage->GetOutputStream(offset, result);
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}
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nsresult
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nsMemoryCacheDevice::GetFileForEntry( nsCacheEntry * entry,
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nsIFile ** result )
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{
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return NS_ERROR_NOT_IMPLEMENTED;
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}
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nsresult
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nsMemoryCacheDevice::OnDataSizeChange( nsCacheEntry * entry, PRInt32 deltaSize)
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{
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if (entry->IsStreamData()) {
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// we have the right to refuse or pre-evict
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PRUint32 newSize = entry->DataSize() + deltaSize;
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if ((PRInt32) newSize > mSoftLimit) {
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nsresult rv = nsCacheService::DoomEntry(entry);
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NS_ASSERTION(NS_SUCCEEDED(rv),"DoomEntry() failed.");
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return NS_ERROR_ABORT;
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}
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}
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// adjust our totals
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mTotalSize += deltaSize;
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if (!entry->IsDoomed()) {
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// move entry to the tail of the appropriate eviction list
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PR_REMOVE_AND_INIT_LINK(entry);
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EnsureEvictionLists();
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PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, deltaSize)]);
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}
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EvictEntriesIfNecessary();
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return NS_OK;
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}
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void
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nsMemoryCacheDevice::AdjustMemoryLimits(PRInt32 softLimit, PRInt32 hardLimit)
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{
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mSoftLimit = softLimit;
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mHardLimit = hardLimit;
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// First, evict entries that won't fit into the new cache size.
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EvictEntriesIfNecessary();
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// Create the eviction list array at the new size and then insert
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// all of the entries into it.
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PRInt32 oldQueueCount = mQueueCount;
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PRCList* oldEvictionList = mEvictionList;
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CreateEvictionLists();
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for (PRInt32 i = PR_MIN(oldQueueCount, mQueueCount) - 1; i >= 0; --i) {
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nsCacheEntry* entry = (nsCacheEntry*) PR_LIST_HEAD(&oldEvictionList[i]);
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while (entry != &oldEvictionList[i]) {
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nsCacheEntry* next = (nsCacheEntry*) PR_NEXT_LINK(entry);
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PR_APPEND_LINK(entry, &mEvictionList[i]);
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entry = next;
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}
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}
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delete[] oldEvictionList;
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}
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void
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nsMemoryCacheDevice::EvictEntry(nsCacheEntry * entry)
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{
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// remove entry from our hashtable
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mMemCacheEntries.RemoveEntry(entry);
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// remove entry from the eviction list
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PR_REMOVE_AND_INIT_LINK(entry);
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// update statistics
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PRInt32 memoryRecovered = (PRInt32)entry->Size();
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mTotalSize -= memoryRecovered;
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mInactiveSize -= memoryRecovered;
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--mEntryCount;
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delete entry;
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}
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void
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nsMemoryCacheDevice::EvictEntriesIfNecessary(void)
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{
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nsCacheEntry * entry, * next;
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if ((mTotalSize < mHardLimit) && (mInactiveSize < mSoftLimit))
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return;
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for (int i = mQueueCount - 1; i >= 0; --i) {
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entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
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while (entry != &mEvictionList[i]) {
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if (entry->IsInUse()) {
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entry = (nsCacheEntry *)PR_NEXT_LINK(entry);
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continue;
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}
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next = (nsCacheEntry *)PR_NEXT_LINK(entry);
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EvictEntry(entry);
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entry = next;
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if ((mTotalSize < mHardLimit) && (mInactiveSize < mSoftLimit))
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return;
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}
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}
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}
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int
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nsMemoryCacheDevice::EvictionList(nsCacheEntry * entry, PRInt32 deltaSize)
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{
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PRInt32 size = deltaSize + (PRInt32)entry->Size();
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// favor items which never expire by putting them in the lowest-index queue
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if (entry->ExpirationTime() == NO_EXPIRATION_TIME)
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return 0;
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// compute which eviction queue this entry should go into, based on
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// floor(log2(size/nref))
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return PR_FloorLog2(size / (entry->FetchCount() + 1));
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}
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nsresult
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nsMemoryCacheDevice::Visit(nsICacheVisitor * visitor)
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{
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nsMemoryCacheDeviceInfo * deviceInfo = new nsMemoryCacheDeviceInfo(this);
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nsCOMPtr<nsICacheDeviceInfo> deviceRef(deviceInfo);
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if (!deviceInfo) return NS_ERROR_OUT_OF_MEMORY;
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PRBool keepGoing;
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nsresult rv = visitor->VisitDevice(gMemoryDeviceID, deviceInfo, &keepGoing);
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if (NS_FAILED(rv)) return rv;
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if (!keepGoing)
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return NS_OK;
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nsCacheEntry * entry;
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nsCOMPtr<nsICacheEntryInfo> entryRef;
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for (int i = mQueueCount - 1; i >= 0; --i) {
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entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
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while (entry != &mEvictionList[i]) {
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nsCacheEntryInfo * entryInfo = new nsCacheEntryInfo(entry);
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if (!entryInfo) return NS_ERROR_OUT_OF_MEMORY;
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entryRef = entryInfo;
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rv = visitor->VisitEntry(gMemoryDeviceID, entryInfo, &keepGoing);
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entryInfo->DetachEntry();
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if (NS_FAILED(rv)) return rv;
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if (!keepGoing) break;
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entry = (nsCacheEntry *)PR_NEXT_LINK(entry);
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}
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}
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return NS_OK;
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}
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nsresult
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nsMemoryCacheDevice::EvictEntries(const char * clientID)
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{
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nsCacheEntry * entry;
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PRUint32 prefixLength = (clientID ? strlen(clientID) : 0);
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for (int i = mQueueCount - 1; i >= 0; --i) {
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PRCList * elem = PR_LIST_HEAD(&mEvictionList[i]);
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while (elem != &mEvictionList[i]) {
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entry = (nsCacheEntry *)elem;
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elem = PR_NEXT_LINK(elem);
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const char * key = entry->Key()->get();
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if (clientID && nsCRT::strncmp(clientID, key, prefixLength) != 0)
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continue;
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if (entry->IsInUse()) {
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nsresult rv = nsCacheService::DoomEntry(entry);
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if (NS_FAILED(rv)) return rv;
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} else {
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EvictEntry(entry);
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}
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}
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}
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return NS_OK;
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}
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void
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nsMemoryCacheDevice::SetCapacity(PRInt32 capacity)
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{
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PRInt32 hardLimit = capacity * 1024; // convert k into bytes
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PRInt32 softLimit = (hardLimit * 9) / 10;
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AdjustMemoryLimits(softLimit, hardLimit);
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}
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inline void
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nsMemoryCacheDevice::EnsureEvictionLists()
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{
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if (!mEvictionList)
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CreateEvictionLists();
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}
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void
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nsMemoryCacheDevice::CreateEvictionLists()
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{
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// Create log2 (mHardLimit + 1) LRU queues
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mQueueCount = PR_CeilingLog2(mHardLimit + 1);
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mEvictionList = new PRCList[mQueueCount];
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for (int i = 0; i < mQueueCount; ++i)
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PR_INIT_CLIST(&mEvictionList[i]);
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}
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/******************************************************************************
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* nsMemoryCacheDeviceInfo - for implementing about:cache
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*****************************************************************************/
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NS_IMPL_ISUPPORTS1(nsMemoryCacheDeviceInfo, nsICacheDeviceInfo);
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NS_IMETHODIMP
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nsMemoryCacheDeviceInfo::GetDescription(char ** result)
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{
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NS_ENSURE_ARG_POINTER(result);
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*result = nsCRT::strdup("Memory cache device");
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if (!*result) return NS_ERROR_OUT_OF_MEMORY;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMemoryCacheDeviceInfo::GetUsageReport(char ** result)
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{
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NS_ENSURE_ARG_POINTER(result);
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*result = nsCRT::strdup("Memory cache usage report:");
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if (!*result) return NS_ERROR_OUT_OF_MEMORY;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMemoryCacheDeviceInfo::GetEntryCount(PRUint32 * result)
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{
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NS_ENSURE_ARG_POINTER(result);
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// XXX compare calculated count vs. mEntryCount
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*result = (PRUint32)mDevice->mEntryCount;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMemoryCacheDeviceInfo::GetTotalSize(PRUint32 * result)
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{
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NS_ENSURE_ARG_POINTER(result);
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*result = (PRUint32)mDevice->mTotalSize;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMemoryCacheDeviceInfo::GetMaximumSize(PRUint32 * result)
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{
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NS_ENSURE_ARG_POINTER(result);
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*result = (PRUint32)mDevice->mHardLimit;
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return NS_OK;
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}
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