pjs/netwerk/cache/nsMemoryCacheDevice.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** 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 nsMemoryCacheDevice.cpp, released
* February 22, 2001.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Gordon Sheridan, <gordon@netscape.com>
* Patrick C. Beard <beard@netscape.com>
* Brian Ryner <bryner@brianryner.com>
*
* 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 ***** */
#include "nsMemoryCacheDevice.h"
#include "nsCacheService.h"
#include "nsICacheService.h"
#include "nsIStorageStream.h"
#include "nsICacheVisitor.h"
#include "nsCRT.h"
#include "nsCache.h"
#include "nsReadableUtils.h"
#include "mozilla/Telemetry.h"
// The memory cache implements the "LRU-SP" caching algorithm
// described in "LRU-SP: A Size-Adjusted and Popularity-Aware LRU Replacement
// Algorithm for Web Caching" by Kai Cheng and Yahiko Kambayashi.
// We keep kQueueCount LRU queues, which should be about ceil(log2(mHardLimit))
// The queues hold exponentially increasing ranges of floor(log2((size/nref)))
// values for entries.
// Entries larger than 2^(kQueueCount-1) go in the last queue.
// Entries with no expiration go in the first queue.
const char *gMemoryDeviceID = "memory";
nsMemoryCacheDevice::nsMemoryCacheDevice()
: mInitialized(false),
mEvictionThreshold(PR_INT32_MAX),
mHardLimit(4 * 1024 * 1024), // default, if no pref
mSoftLimit((mHardLimit * 9) / 10), // default, if no pref
mTotalSize(0),
mInactiveSize(0),
mEntryCount(0),
mMaxEntryCount(0),
mMaxEntrySize(-1) // -1 means "no limit"
{
for (int i=0; i<kQueueCount; ++i)
PR_INIT_CLIST(&mEvictionList[i]);
}
nsMemoryCacheDevice::~nsMemoryCacheDevice()
{
Shutdown();
}
nsresult
nsMemoryCacheDevice::Init()
{
if (mInitialized) return NS_ERROR_ALREADY_INITIALIZED;
nsresult rv = mMemCacheEntries.Init();
mInitialized = NS_SUCCEEDED(rv);
return rv;
}
nsresult
nsMemoryCacheDevice::Shutdown()
{
NS_ASSERTION(mInitialized, "### attempting shutdown while not initialized");
NS_ENSURE_TRUE(mInitialized, NS_ERROR_NOT_INITIALIZED);
mMemCacheEntries.Shutdown();
// evict all entries
nsCacheEntry * entry, * next;
for (int i = kQueueCount - 1; i >= 0; --i) {
entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
while (entry != &mEvictionList[i]) {
NS_ASSERTION(!entry->IsInUse(), "### shutting down with active entries");
next = (nsCacheEntry *)PR_NEXT_LINK(entry);
PR_REMOVE_AND_INIT_LINK(entry);
// update statistics
PRInt32 memoryRecovered = (PRInt32)entry->DataSize();
mTotalSize -= memoryRecovered;
mInactiveSize -= memoryRecovered;
--mEntryCount;
delete entry;
entry = next;
}
}
/*
* we're not factoring in changes to meta data yet...
* NS_ASSERTION(mTotalSize == 0, "### mem cache leaking entries?");
*/
NS_ASSERTION(mInactiveSize == 0, "### mem cache leaking entries?");
NS_ASSERTION(mEntryCount == 0, "### mem cache leaking entries?");
mInitialized = false;
return NS_OK;
}
const char *
nsMemoryCacheDevice::GetDeviceID()
{
return gMemoryDeviceID;
}
nsCacheEntry *
nsMemoryCacheDevice::FindEntry(nsCString * key, bool *collision)
{
mozilla::Telemetry::AutoTimer<mozilla::Telemetry::CACHE_MEMORY_SEARCH> timer;
nsCacheEntry * entry = mMemCacheEntries.GetEntry(key);
if (!entry) return nsnull;
// move entry to the tail of an eviction list
PR_REMOVE_AND_INIT_LINK(entry);
PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, 0)]);
mInactiveSize -= entry->DataSize();
return entry;
}
nsresult
nsMemoryCacheDevice::DeactivateEntry(nsCacheEntry * entry)
{
CACHE_LOG_DEBUG(("nsMemoryCacheDevice::DeactivateEntry for entry 0x%p\n",
entry));
if (entry->IsDoomed()) {
#ifdef DEBUG
// XXX verify we've removed it from mMemCacheEntries & eviction list
#endif
delete entry;
CACHE_LOG_DEBUG(("deleted doomed entry 0x%p\n", entry));
return NS_OK;
}
#ifdef DEBUG
nsCacheEntry * ourEntry = mMemCacheEntries.GetEntry(entry->Key());
NS_ASSERTION(ourEntry, "DeactivateEntry called for an entry we don't have!");
NS_ASSERTION(entry == ourEntry, "entry doesn't match ourEntry");
if (ourEntry != entry)
return NS_ERROR_INVALID_POINTER;
#endif
mInactiveSize += entry->DataSize();
EvictEntriesIfNecessary();
return NS_OK;
}
nsresult
nsMemoryCacheDevice::BindEntry(nsCacheEntry * entry)
{
if (!entry->IsDoomed()) {
NS_ASSERTION(PR_CLIST_IS_EMPTY(entry),"entry is already on a list!");
// append entry to the eviction list
PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, 0)]);
// add entry to hashtable of mem cache entries
nsresult rv = mMemCacheEntries.AddEntry(entry);
if (NS_FAILED(rv)) {
PR_REMOVE_AND_INIT_LINK(entry);
return rv;
}
// add size of entry to memory totals
++mEntryCount;
if (mMaxEntryCount < mEntryCount) mMaxEntryCount = mEntryCount;
mTotalSize += entry->DataSize();
EvictEntriesIfNecessary();
}
return NS_OK;
}
void
nsMemoryCacheDevice::DoomEntry(nsCacheEntry * entry)
{
#ifdef DEBUG
// debug code to verify we have entry
nsCacheEntry * hashEntry = mMemCacheEntries.GetEntry(entry->Key());
if (!hashEntry) NS_WARNING("no entry for key");
else if (entry != hashEntry) NS_WARNING("entry != hashEntry");
#endif
CACHE_LOG_DEBUG(("Dooming entry 0x%p in memory cache\n", entry));
EvictEntry(entry, DO_NOT_DELETE_ENTRY);
}
nsresult
nsMemoryCacheDevice::OpenInputStreamForEntry( nsCacheEntry * entry,
nsCacheAccessMode mode,
PRUint32 offset,
nsIInputStream ** result)
{
NS_ENSURE_ARG_POINTER(entry);
NS_ENSURE_ARG_POINTER(result);
nsCOMPtr<nsIStorageStream> storage;
nsresult rv;
nsISupports *data = entry->Data();
if (data) {
storage = do_QueryInterface(data, &rv);
if (NS_FAILED(rv))
return rv;
}
else {
rv = NS_NewStorageStream(4096, PRUint32(-1), getter_AddRefs(storage));
if (NS_FAILED(rv))
return rv;
entry->SetData(storage);
}
return storage->NewInputStream(offset, result);
}
nsresult
nsMemoryCacheDevice::OpenOutputStreamForEntry( nsCacheEntry * entry,
nsCacheAccessMode mode,
PRUint32 offset,
nsIOutputStream ** result)
{
NS_ENSURE_ARG_POINTER(entry);
NS_ENSURE_ARG_POINTER(result);
nsCOMPtr<nsIStorageStream> storage;
nsresult rv;
nsISupports *data = entry->Data();
if (data) {
storage = do_QueryInterface(data, &rv);
if (NS_FAILED(rv))
return rv;
}
else {
rv = NS_NewStorageStream(4096, PRUint32(-1), getter_AddRefs(storage));
if (NS_FAILED(rv))
return rv;
entry->SetData(storage);
}
return storage->GetOutputStream(offset, result);
}
nsresult
nsMemoryCacheDevice::GetFileForEntry( nsCacheEntry * entry,
nsIFile ** result )
{
return NS_ERROR_NOT_IMPLEMENTED;
}
bool
nsMemoryCacheDevice::EntryIsTooBig(PRInt64 entrySize)
{
CACHE_LOG_DEBUG(("nsMemoryCacheDevice::EntryIsTooBig "
"[size=%d max=%d soft=%d]\n",
entrySize, mMaxEntrySize, mSoftLimit));
if (mMaxEntrySize == -1)
return entrySize > mSoftLimit;
else
return (entrySize > mSoftLimit || entrySize > mMaxEntrySize);
}
size_t
nsMemoryCacheDevice::TotalSize()
{
return mTotalSize;
}
nsresult
nsMemoryCacheDevice::OnDataSizeChange( nsCacheEntry * entry, PRInt32 deltaSize)
{
if (entry->IsStreamData()) {
// we have the right to refuse or pre-evict
PRUint32 newSize = entry->DataSize() + deltaSize;
if (EntryIsTooBig(newSize)) {
#ifdef DEBUG
nsresult rv =
#endif
nsCacheService::DoomEntry(entry);
NS_ASSERTION(NS_SUCCEEDED(rv),"DoomEntry() failed.");
return NS_ERROR_ABORT;
}
}
// adjust our totals
mTotalSize += deltaSize;
if (!entry->IsDoomed()) {
// move entry to the tail of the appropriate eviction list
PR_REMOVE_AND_INIT_LINK(entry);
PR_APPEND_LINK(entry, &mEvictionList[EvictionList(entry, deltaSize)]);
}
EvictEntriesIfNecessary();
return NS_OK;
}
void
nsMemoryCacheDevice::AdjustMemoryLimits(PRInt32 softLimit, PRInt32 hardLimit)
{
mSoftLimit = softLimit;
mHardLimit = hardLimit;
// First, evict entries that won't fit into the new cache size.
EvictEntriesIfNecessary();
}
void
nsMemoryCacheDevice::EvictEntry(nsCacheEntry * entry, bool deleteEntry)
{
CACHE_LOG_DEBUG(("Evicting entry 0x%p from memory cache, deleting: %d\n",
entry, deleteEntry));
// remove entry from our hashtable
mMemCacheEntries.RemoveEntry(entry);
// remove entry from the eviction list
PR_REMOVE_AND_INIT_LINK(entry);
// update statistics
PRInt32 memoryRecovered = (PRInt32)entry->DataSize();
mTotalSize -= memoryRecovered;
if (!entry->IsDoomed())
mInactiveSize -= memoryRecovered;
--mEntryCount;
if (deleteEntry) delete entry;
}
void
nsMemoryCacheDevice::EvictEntriesIfNecessary(void)
{
nsCacheEntry * entry;
nsCacheEntry * maxEntry;
CACHE_LOG_DEBUG(("EvictEntriesIfNecessary. mTotalSize: %d, mHardLimit: %d,"
"mInactiveSize: %d, mSoftLimit: %d\n",
mTotalSize, mHardLimit, mInactiveSize, mSoftLimit));
if ((mTotalSize < mHardLimit) && (mInactiveSize < mSoftLimit))
return;
PRUint32 now = SecondsFromPRTime(PR_Now());
PRUint64 entryCost = 0;
PRUint64 maxCost = 0;
do {
// LRU-SP eviction selection: Check the head of each segment (each
// eviction list, kept in LRU order) and select the maximal-cost
// entry for eviction. Cost is time-since-accessed * size / nref.
maxEntry = 0;
for (int i = kQueueCount - 1; i >= 0; --i) {
entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
// If the head of a list is in use, check the next available entry
while ((entry != &mEvictionList[i]) &&
(entry->IsInUse())) {
entry = (nsCacheEntry *)PR_NEXT_LINK(entry);
}
if (entry != &mEvictionList[i]) {
entryCost = (PRUint64)
(now - entry->LastFetched()) * entry->DataSize() /
PR_MAX(1, entry->FetchCount());
if (!maxEntry || (entryCost > maxCost)) {
maxEntry = entry;
maxCost = entryCost;
}
}
}
if (maxEntry) {
EvictEntry(maxEntry, DELETE_ENTRY);
} else {
break;
}
}
while ((mTotalSize >= mHardLimit) || (mInactiveSize >= mSoftLimit));
}
int
nsMemoryCacheDevice::EvictionList(nsCacheEntry * entry, PRInt32 deltaSize)
{
// favor items which never expire by putting them in the lowest-index queue
if (entry->ExpirationTime() == nsICache::NO_EXPIRATION_TIME)
return 0;
// compute which eviction queue this entry should go into,
// based on floor(log2(size/nref))
PRInt32 size = deltaSize + (PRInt32)entry->DataSize();
PRInt32 fetchCount = NS_MAX(1, entry->FetchCount());
return NS_MIN(PR_FloorLog2(size / fetchCount), kQueueCount - 1);
}
nsresult
nsMemoryCacheDevice::Visit(nsICacheVisitor * visitor)
{
nsMemoryCacheDeviceInfo * deviceInfo = new nsMemoryCacheDeviceInfo(this);
nsCOMPtr<nsICacheDeviceInfo> deviceRef(deviceInfo);
if (!deviceInfo) return NS_ERROR_OUT_OF_MEMORY;
bool keepGoing;
nsresult rv = visitor->VisitDevice(gMemoryDeviceID, deviceInfo, &keepGoing);
if (NS_FAILED(rv)) return rv;
if (!keepGoing)
return NS_OK;
nsCacheEntry * entry;
nsCOMPtr<nsICacheEntryInfo> entryRef;
for (int i = kQueueCount - 1; i >= 0; --i) {
entry = (nsCacheEntry *)PR_LIST_HEAD(&mEvictionList[i]);
while (entry != &mEvictionList[i]) {
nsCacheEntryInfo * entryInfo = new nsCacheEntryInfo(entry);
if (!entryInfo) return NS_ERROR_OUT_OF_MEMORY;
entryRef = entryInfo;
rv = visitor->VisitEntry(gMemoryDeviceID, entryInfo, &keepGoing);
entryInfo->DetachEntry();
if (NS_FAILED(rv)) return rv;
if (!keepGoing) break;
entry = (nsCacheEntry *)PR_NEXT_LINK(entry);
}
}
return NS_OK;
}
nsresult
nsMemoryCacheDevice::EvictEntries(const char * clientID)
{
nsCacheEntry * entry;
PRUint32 prefixLength = (clientID ? strlen(clientID) : 0);
for (int i = kQueueCount - 1; i >= 0; --i) {
PRCList * elem = PR_LIST_HEAD(&mEvictionList[i]);
while (elem != &mEvictionList[i]) {
entry = (nsCacheEntry *)elem;
elem = PR_NEXT_LINK(elem);
const char * key = entry->Key()->get();
if (clientID && nsCRT::strncmp(clientID, key, prefixLength) != 0)
continue;
if (entry->IsInUse()) {
nsresult rv = nsCacheService::DoomEntry(entry);
if (NS_FAILED(rv)) {
CACHE_LOG_WARNING(("memCache->EvictEntries() aborted: rv =%x", rv));
return rv;
}
} else {
EvictEntry(entry, DELETE_ENTRY);
}
}
}
return NS_OK;
}
// WARNING: SetCapacity can get called before Init()
void
nsMemoryCacheDevice::SetCapacity(PRInt32 capacity)
{
PRInt32 hardLimit = capacity * 1024; // convert k into bytes
PRInt32 softLimit = (hardLimit * 9) / 10;
AdjustMemoryLimits(softLimit, hardLimit);
}
void
nsMemoryCacheDevice::SetMaxEntrySize(PRInt32 maxSizeInKilobytes)
{
// Internal unit is bytes. Changing this only takes effect *after* the
// change and has no consequences for existing cache-entries
if (maxSizeInKilobytes >= 0)
mMaxEntrySize = maxSizeInKilobytes * 1024;
else
mMaxEntrySize = -1;
}
#ifdef DEBUG
static PLDHashOperator
CountEntry(PLDHashTable * table, PLDHashEntryHdr * hdr, PRUint32 number, void * arg)
{
PRInt32 *entryCount = (PRInt32 *)arg;
++(*entryCount);
return PL_DHASH_NEXT;
}
void
nsMemoryCacheDevice::CheckEntryCount()
{
if (!mInitialized) return;
PRInt32 evictionListCount = 0;
for (int i=0; i<kQueueCount; ++i) {
PRCList * elem = PR_LIST_HEAD(&mEvictionList[i]);
while (elem != &mEvictionList[i]) {
elem = PR_NEXT_LINK(elem);
++evictionListCount;
}
}
NS_ASSERTION(mEntryCount == evictionListCount, "### mem cache badness");
PRInt32 entryCount = 0;
mMemCacheEntries.VisitEntries(CountEntry, &entryCount);
NS_ASSERTION(mEntryCount == entryCount, "### mem cache badness");
}
#endif
/******************************************************************************
* nsMemoryCacheDeviceInfo - for implementing about:cache
*****************************************************************************/
NS_IMPL_ISUPPORTS1(nsMemoryCacheDeviceInfo, nsICacheDeviceInfo)
NS_IMETHODIMP
nsMemoryCacheDeviceInfo::GetDescription(char ** result)
{
NS_ENSURE_ARG_POINTER(result);
*result = NS_strdup("Memory cache device");
if (!*result) return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
NS_IMETHODIMP
nsMemoryCacheDeviceInfo::GetUsageReport(char ** result)
{
NS_ENSURE_ARG_POINTER(result);
nsCString buffer;
buffer.AssignLiteral(" <tr>\n"
" <th>Inactive storage:</th>\n"
" <td>");
buffer.AppendInt(mDevice->mInactiveSize / 1024);
buffer.AppendLiteral(" KiB</td>\n"
" </tr>\n");
*result = ToNewCString(buffer);
if (!*result) return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
NS_IMETHODIMP
nsMemoryCacheDeviceInfo::GetEntryCount(PRUint32 * result)
{
NS_ENSURE_ARG_POINTER(result);
// XXX compare calculated count vs. mEntryCount
*result = (PRUint32)mDevice->mEntryCount;
return NS_OK;
}
NS_IMETHODIMP
nsMemoryCacheDeviceInfo::GetTotalSize(PRUint32 * result)
{
NS_ENSURE_ARG_POINTER(result);
*result = (PRUint32)mDevice->mTotalSize;
return NS_OK;
}
NS_IMETHODIMP
nsMemoryCacheDeviceInfo::GetMaximumSize(PRUint32 * result)
{
NS_ENSURE_ARG_POINTER(result);
*result = (PRUint32)mDevice->mHardLimit;
return NS_OK;
}