The Tor Browser: netwerk/cache/nsMemoryCacheDevice.cpp@6474c204b198 (annotated)

netwerk/cache/nsMemoryCacheDevice.cpp@6474c204b198 (annotated)

netwerk/cache/nsMemoryCacheDevice.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* vim: set ts=8 sts=4 et sw=4 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsCache.h"
 #include "nsMemoryCacheDevice.h"
 #include "nsCacheService.h"
 #include "nsICacheService.h"
 #include "nsICacheVisitor.h"
 #include "nsIStorageStream.h"
 #include "nsCRT.h"
 #include "nsReadableUtils.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/Telemetry.h"
 #include <algorithm>
 // 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),
       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
             int32_t memoryRecovered = (int32_t)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_2> timer;
     nsCacheEntry * entry = mMemCacheEntries.GetEntry(key);
     if (!entry)  return nullptr;
     // 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,
                                               uint32_t          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, uint32_t(-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,
                                                uint32_t           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, uint32_t(-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(int64_t 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, int32_t deltaSize)
 {
     if (entry->IsStreamData()) {
         // we have the right to refuse or pre-evict
         uint32_t  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(int32_t  softLimit, int32_t  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
     int32_t memoryRecovered = (int32_t)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;
     uint32_t now = SecondsFromPRTime(PR_Now());
     uint64_t entryCost = 0;
     uint64_t 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 = (uint64_t)
                     (now - entry->LastFetched()) * entry->DataSize() /
                     std::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, int32_t  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))
     int32_t  size       = deltaSize + (int32_t)entry->DataSize();
     int32_t  fetchCount = std::max(1, entry->FetchCount());
     return std::min((int)mozilla::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;
 }
 static bool
 IsEntryPrivate(nsCacheEntry* entry, void* args)
 {
     return entry->IsPrivate();
 }
 struct ClientIDArgs {
     const char* clientID;
     uint32_t prefixLength;
 };
 static bool
 EntryMatchesClientID(nsCacheEntry* entry, void* args)
 {
     const char * clientID = static_cast<ClientIDArgs*>(args)->clientID;
     uint32_t prefixLength = static_cast<ClientIDArgs*>(args)->prefixLength;
     const char * key = entry->Key()->get();
     return !clientID || nsCRT::strncmp(clientID, key, prefixLength) == 0;
 }
 nsresult
 nsMemoryCacheDevice::DoEvictEntries(bool (*matchFn)(nsCacheEntry* entry, void* args), void* args)
 {
     nsCacheEntry * entry;
     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);
             if (!matchFn(entry, args))
                 continue;
             if (entry->IsInUse()) {
                 nsresult rv = nsCacheService::DoomEntry(entry);
                 if (NS_FAILED(rv)) {
                     CACHE_LOG_WARNING(("memCache->DoEvictEntries() aborted: rv =%x", rv));
                     return rv;
                 }
             } else {
                 EvictEntry(entry, DELETE_ENTRY);
             }
         }
     }
     return NS_OK;
 }
 nsresult
 nsMemoryCacheDevice::EvictEntries(const char * clientID)
 {
     ClientIDArgs args = {clientID, clientID ? uint32_t(strlen(clientID)) : 0};
     return DoEvictEntries(&EntryMatchesClientID, &args);
 }
 nsresult
 nsMemoryCacheDevice::EvictPrivateEntries()
 {
     return DoEvictEntries(&IsEntryPrivate, nullptr);
 }
 // WARNING: SetCapacity can get called before Init()
 void
 nsMemoryCacheDevice::SetCapacity(int32_t  capacity)
 {
     int32_t hardLimit = capacity * 1024;  // convert k into bytes
     int32_t softLimit = (hardLimit * 9) / 10;
     AdjustMemoryLimits(softLimit, hardLimit);
 }
 void
 nsMemoryCacheDevice::SetMaxEntrySize(int32_t 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, uint32_t number, void * arg)
 {
     int32_t *entryCount = (int32_t *)arg;
     ++(*entryCount);
     return PL_DHASH_NEXT;
 }
 void
 nsMemoryCacheDevice::CheckEntryCount()
 {
     if (!mInitialized)  return;
     int32_t 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");
     int32_t entryCount = 0;
     mMemCacheEntries.VisitEntries(CountEntry, &entryCount);
     NS_ASSERTION(mEntryCount == entryCount, "### mem cache badness");
 }
 #endif
 /******************************************************************************
  * nsMemoryCacheDeviceInfo - for implementing about:cache
  *****************************************************************************/
 NS_IMPL_ISUPPORTS(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(uint32_t * result)
 {
     NS_ENSURE_ARG_POINTER(result);
     // XXX compare calculated count vs. mEntryCount
     *result = (uint32_t)mDevice->mEntryCount;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsMemoryCacheDeviceInfo::GetTotalSize(uint32_t * result)
 {
     NS_ENSURE_ARG_POINTER(result);
     *result = (uint32_t)mDevice->mTotalSize;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsMemoryCacheDeviceInfo::GetMaximumSize(uint32_t * result)
 {
     NS_ENSURE_ARG_POINTER(result);
     *result = (uint32_t)mDevice->mHardLimit;
     return NS_OK;
 }

The Tor Browser / annotate

netwerk/cache/nsMemoryCacheDevice.cpp@6474c204b198 (annotated)

netwerk/cache/nsMemoryCacheDevice.cpp