The Tor Browser: netwerk/cache/nsDiskCacheBinding.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsDiskCacheBinding.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsDiskCacheBinding.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * 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 "mozilla/MemoryReporting.h"
 #include "nsCache.h"
 #include <limits.h>
 #include "nscore.h"
 #include "nsDiskCacheBinding.h"
 #include "nsCacheService.h"
 /******************************************************************************
  *  static hash table callback functions
  *
  *****************************************************************************/
 struct HashTableEntry : PLDHashEntryHdr {
     nsDiskCacheBinding *  mBinding;
 };
 static PLDHashNumber
 HashKey( PLDHashTable *table, const void *key)
 {
     return (PLDHashNumber) NS_PTR_TO_INT32(key);
 }
 static bool
 MatchEntry(PLDHashTable *              /* table */,
             const PLDHashEntryHdr *       header,
             const void *                  key)
 {
     HashTableEntry * hashEntry = (HashTableEntry *) header;
     return (hashEntry->mBinding->mRecord.HashNumber() == (PLDHashNumber) NS_PTR_TO_INT32(key));
 }
 static void
 MoveEntry(PLDHashTable *           /* table */,
           const PLDHashEntryHdr *     src,
           PLDHashEntryHdr       *     dst)
 {
     ((HashTableEntry *)dst)->mBinding = ((HashTableEntry *)src)->mBinding;
 }
 static void
 ClearEntry(PLDHashTable *      /* table */,
            PLDHashEntryHdr *      header)
 {
     ((HashTableEntry *)header)->mBinding = nullptr;
 }
 /******************************************************************************
  *  Utility Functions
  *****************************************************************************/
 nsDiskCacheBinding *
 GetCacheEntryBinding(nsCacheEntry * entry)
 {
     return (nsDiskCacheBinding *) entry->Data();
 }
 /******************************************************************************
  *  nsDiskCacheBinding
  *****************************************************************************/
 NS_IMPL_ISUPPORTS0(nsDiskCacheBinding)
 nsDiskCacheBinding::nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record)
     :   mCacheEntry(entry)
     ,   mStreamIO(nullptr)
     ,   mDeactivateEvent(nullptr)
 {
     NS_ASSERTION(record->ValidRecord(), "bad record");
     PR_INIT_CLIST(this);
     mRecord     = *record;
     mDoomed     = entry->IsDoomed();
     mGeneration = record->Generation();    // 0 == uninitialized, or data & meta using block files
 }
 nsDiskCacheBinding::~nsDiskCacheBinding()
 {
     // Grab the cache lock since the binding is stored in nsCacheEntry::mData
     // and it is released using nsCacheService::ReleaseObject_Locked() which
     // releases the object outside the cache lock.
     nsCacheServiceAutoLock lock(LOCK_TELEM(NSDISKCACHEBINDING_DESTRUCTOR));
     NS_ASSERTION(PR_CLIST_IS_EMPTY(this), "binding deleted while still on list");
     if (!PR_CLIST_IS_EMPTY(this))
         PR_REMOVE_LINK(this);       // XXX why are we still on a list?
     // sever streamIO/binding link
     if (mStreamIO) {
         if (NS_FAILED(mStreamIO->ClearBinding()))
             nsCacheService::DoomEntry(mCacheEntry);
         NS_RELEASE(mStreamIO);
     }
 }
 nsresult
 nsDiskCacheBinding::EnsureStreamIO()
 {
     if (!mStreamIO) {
         mStreamIO = new nsDiskCacheStreamIO(this);
         if (!mStreamIO)  return NS_ERROR_OUT_OF_MEMORY;
         NS_ADDREF(mStreamIO);
     }
     return NS_OK;
 }
 /******************************************************************************
  *  nsDiskCacheBindery
  *
  *  Keeps track of bound disk cache entries to detect for collisions.
  *
  *****************************************************************************/
 const PLDHashTableOps nsDiskCacheBindery::ops =
 {
     PL_DHashAllocTable,
     PL_DHashFreeTable,
     HashKey,
     MatchEntry,
     MoveEntry,
     ClearEntry,
     PL_DHashFinalizeStub
 };
 nsDiskCacheBindery::nsDiskCacheBindery()
     : initialized(false)
 {
 }
 nsDiskCacheBindery::~nsDiskCacheBindery()
 {
     Reset();
 }
 nsresult
 nsDiskCacheBindery::Init()
 {
     nsresult rv = NS_OK;
     PL_DHashTableInit(&table, &ops, nullptr, sizeof(HashTableEntry), 0);
     initialized = true;
     return rv;
 }
 void
 nsDiskCacheBindery::Reset()
 {
     if (initialized) {
         PL_DHashTableFinish(&table);
         initialized = false;
     }
 }
 nsDiskCacheBinding *
 nsDiskCacheBindery::CreateBinding(nsCacheEntry *       entry,
                                   nsDiskCacheRecord *  record)
 {
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     nsCOMPtr<nsISupports> data = entry->Data();
     if (data) {
         NS_ERROR("cache entry already has bind data");
         return nullptr;
     }
     nsDiskCacheBinding * binding = new nsDiskCacheBinding(entry, record);
     if (!binding)  return nullptr;
     // give ownership of the binding to the entry
     entry->SetData(binding);
     // add binding to collision detection system
     nsresult rv = AddBinding(binding);
     if (NS_FAILED(rv)) {
         entry->SetData(nullptr);
         return nullptr;
     }
     return binding;
 }
 /**
  *  FindActiveEntry :  to find active colliding entry so we can doom it
  */
 nsDiskCacheBinding *
 nsDiskCacheBindery::FindActiveBinding(uint32_t  hashNumber)
 {
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     // find hash entry for key
     HashTableEntry * hashEntry;
     hashEntry =
       (HashTableEntry *) PL_DHashTableOperate(&table,
                                               (void*)(uintptr_t) hashNumber,
                                               PL_DHASH_LOOKUP);
     if (PL_DHASH_ENTRY_IS_FREE(hashEntry)) return nullptr;
     // walk list looking for active entry
     NS_ASSERTION(hashEntry->mBinding, "hash entry left with no binding");
     nsDiskCacheBinding * binding = hashEntry->mBinding;
     while (binding->mCacheEntry->IsDoomed()) {
         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
         if (binding == hashEntry->mBinding)  return nullptr;
     }
     return binding;
 }
 /**
  *  AddBinding
  *
  *  Called from FindEntry() if we read an entry off of disk
  *      - it may already have a generation number
  *      - a generation number conflict is an error
  *
  *  Called from BindEntry()
  *      - a generation number needs to be assigned
  */
 nsresult
 nsDiskCacheBindery::AddBinding(nsDiskCacheBinding * binding)
 {
     NS_ENSURE_ARG_POINTER(binding);
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     // find hash entry for key
     HashTableEntry * hashEntry;
     hashEntry = (HashTableEntry *)
       PL_DHashTableOperate(&table,
                            (void *)(uintptr_t) binding->mRecord.HashNumber(),
                            PL_DHASH_ADD);
     if (!hashEntry) return NS_ERROR_OUT_OF_MEMORY;
     if (hashEntry->mBinding == nullptr) {
         hashEntry->mBinding = binding;
         if (binding->mGeneration == 0)
             binding->mGeneration = 1;   // if generation uninitialized, set it to 1
         return NS_OK;
     }
     // insert binding in generation order
     nsDiskCacheBinding * p  = hashEntry->mBinding;
     bool     calcGeneration = (binding->mGeneration == 0);  // do we need to calculate generation?
     if (calcGeneration)  binding->mGeneration = 1;          // initialize to 1 if uninitialized
     while (1) {
         if (binding->mGeneration < p->mGeneration) {
             // here we are
             PR_INSERT_BEFORE(binding, p);
             if (hashEntry->mBinding == p)
                 hashEntry->mBinding = binding;
             break;
         }
         if (binding->mGeneration == p->mGeneration) {
             if (calcGeneration)  ++binding->mGeneration;    // try the next generation
             else {
                 NS_ERROR("### disk cache: generations collide!");
                 return NS_ERROR_UNEXPECTED;
             }
         }
         p = (nsDiskCacheBinding *)PR_NEXT_LINK(p);
         if (p == hashEntry->mBinding) {
             // end of line: insert here or die
             p = (nsDiskCacheBinding *)PR_PREV_LINK(p);  // back up and check generation
             if (p->mGeneration == 255) {
                 NS_WARNING("### disk cache: generation capacity at full");
                 return NS_ERROR_UNEXPECTED;
             }
             PR_INSERT_BEFORE(binding, hashEntry->mBinding);
             break;
         }
     }
     return NS_OK;
 }
 /**
  *  RemoveBinding :  remove binding from collision detection on deactivation
  */
 void
 nsDiskCacheBindery::RemoveBinding(nsDiskCacheBinding * binding)
 {
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     if (!initialized)   return;
     HashTableEntry * hashEntry;
     void           * key = (void *)(uintptr_t)binding->mRecord.HashNumber();
     hashEntry = (HashTableEntry*) PL_DHashTableOperate(&table,
                                                        (void*)(uintptr_t) key,
                                                        PL_DHASH_LOOKUP);
     if (!PL_DHASH_ENTRY_IS_BUSY(hashEntry)) {
         NS_WARNING("### disk cache: binding not in hashtable!");
         return;
     }
     if (binding == hashEntry->mBinding) {
         if (PR_CLIST_IS_EMPTY(binding)) {
             // remove this hash entry
             PL_DHashTableOperate(&table,
                                  (void*)(uintptr_t) binding->mRecord.HashNumber(),
                                  PL_DHASH_REMOVE);
             return;
         } else {
             // promote next binding to head, and unlink this binding
             hashEntry->mBinding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
         }
     }
     PR_REMOVE_AND_INIT_LINK(binding);
 }
 /**
  *  ActiveBinding : PLDHashTable enumerate function to verify active bindings
  */
 PLDHashOperator
 ActiveBinding(PLDHashTable *    table,
               PLDHashEntryHdr * hdr,
               uint32_t          number,
               void *            arg)
 {
     nsDiskCacheBinding * binding = ((HashTableEntry *)hdr)->mBinding;
     NS_ASSERTION(binding, "### disk cache binding = nullptr!");
     nsDiskCacheBinding * head = binding;
     do {
         if (binding->IsActive()) {
            *((bool *)arg) = true;
             return PL_DHASH_STOP;
         }
         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
     } while (binding != head);
     return PL_DHASH_NEXT;
 }
 /**
  *  ActiveBindings : return true if any bindings have open descriptors
  */
 bool
 nsDiskCacheBindery::ActiveBindings()
 {
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     if (!initialized) return false;
     bool    activeBinding = false;
     PL_DHashTableEnumerate(&table, ActiveBinding, &activeBinding);
     return activeBinding;
 }
 struct AccumulatorArg {
     size_t mUsage;
     mozilla::MallocSizeOf mMallocSizeOf;
 };
 PLDHashOperator
 AccumulateHeapUsage(PLDHashTable *table, PLDHashEntryHdr *hdr, uint32_t number,
                     void *arg)
 {
     nsDiskCacheBinding *binding = ((HashTableEntry *)hdr)->mBinding;
     NS_ASSERTION(binding, "### disk cache binding = nsnull!");
     AccumulatorArg *acc = (AccumulatorArg *)arg;
     nsDiskCacheBinding *head = binding;
     do {
         acc->mUsage += acc->mMallocSizeOf(binding);
         if (binding->mStreamIO) {
             acc->mUsage += binding->mStreamIO->SizeOfIncludingThis(acc->mMallocSizeOf);
         }
         /* No good way to get at mDeactivateEvent internals for proper size, so
            we use this as an estimate. */
         if (binding->mDeactivateEvent) {
             acc->mUsage += acc->mMallocSizeOf(binding->mDeactivateEvent);
         }
         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
     } while (binding != head);
     return PL_DHASH_NEXT;
 }
 /**
  * SizeOfExcludingThis: return the amount of heap memory (bytes) being used by the bindery
  */
 size_t
 nsDiskCacheBindery::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf)
 {
     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
     if (!initialized) return 0;
     AccumulatorArg arg;
     arg.mUsage = 0;
     arg.mMallocSizeOf = aMallocSizeOf;
     PL_DHashTableEnumerate(&table, AccumulateHeapUsage, &arg);
     return arg.mUsage;
 }

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netwerk/cache/nsDiskCacheBinding.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsDiskCacheBinding.cpp