netwerk/cache/nsDiskCacheBinding.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsCache.h"
   8 #include <limits.h>
   9
  10 #include "nscore.h"
  11 #include "nsDiskCacheBinding.h"
  12 #include "nsCacheService.h"
  13
  14
  15
  16 /******************************************************************************
  17  *  static hash table callback functions
  18  *
  19  *****************************************************************************/
  20 struct HashTableEntry : PLDHashEntryHdr {
  21     nsDiskCacheBinding *  mBinding;
  22 };
  23
  24
  25 static PLDHashNumber
  26 HashKey( PLDHashTable *table, const void *key)
  27 {
  28     return (PLDHashNumber) NS_PTR_TO_INT32(key);
  29 }
  30
  31
  32 static bool
  33 MatchEntry(PLDHashTable *              /* table */,
  34             const PLDHashEntryHdr *       header,
  35             const void *                  key)
  36 {
  37     HashTableEntry * hashEntry = (HashTableEntry *) header;
  38     return (hashEntry->mBinding->mRecord.HashNumber() == (PLDHashNumber) NS_PTR_TO_INT32(key));
  39 }
  40
  41 static void
  42 MoveEntry(PLDHashTable *           /* table */,
  43           const PLDHashEntryHdr *     src,
  44           PLDHashEntryHdr       *     dst)
  45 {
  46     ((HashTableEntry *)dst)->mBinding = ((HashTableEntry *)src)->mBinding;
  47 }
  48
  49
  50 static void
  51 ClearEntry(PLDHashTable *      /* table */,
  52            PLDHashEntryHdr *      header)
  53 {
  54     ((HashTableEntry *)header)->mBinding = nullptr;
  55 }
  56
  57
  58 /******************************************************************************
  59  *  Utility Functions
  60  *****************************************************************************/
  61 nsDiskCacheBinding *
  62 GetCacheEntryBinding(nsCacheEntry * entry)
  63 {
  64     return (nsDiskCacheBinding *) entry->Data();
  65 }
  66
  67
  68 /******************************************************************************
  69  *  nsDiskCacheBinding
  70  *****************************************************************************/
  71
  72 NS_IMPL_THREADSAFE_ISUPPORTS0(nsDiskCacheBinding)
  73
  74 nsDiskCacheBinding::nsDiskCacheBinding(nsCacheEntry* entry, nsDiskCacheRecord * record)
  75     :   mCacheEntry(entry)
  76     ,   mStreamIO(nullptr)
  77     ,   mDeactivateEvent(nullptr)
  78 {
  79     NS_ASSERTION(record->ValidRecord(), "bad record");
  80     PR_INIT_CLIST(this);
  81     mRecord     = *record;
  82     mDoomed     = entry->IsDoomed();
  83     mGeneration = record->Generation();    // 0 == uninitialized, or data & meta using block files
  84 }
  85
  86 nsDiskCacheBinding::~nsDiskCacheBinding()
  87 {
  88     // Grab the cache lock since the binding is stored in nsCacheEntry::mData
  89     // and it is released using nsCacheService::ReleaseObject_Locked() which
  90     // releases the object outside the cache lock.
  91     nsCacheServiceAutoLock lock(LOCK_TELEM(NSDISKCACHEBINDING_DESTRUCTOR));
  92
  93     NS_ASSERTION(PR_CLIST_IS_EMPTY(this), "binding deleted while still on list");
  94     if (!PR_CLIST_IS_EMPTY(this))
  95         PR_REMOVE_LINK(this);       // XXX why are we still on a list?
  96
  97     // sever streamIO/binding link
  98     if (mStreamIO) {
  99         if (NS_FAILED(mStreamIO->ClearBinding()))
 100             nsCacheService::DoomEntry(mCacheEntry);
 101         NS_RELEASE(mStreamIO);
 102     }
 103 }
 104
 105 nsresult
 106 nsDiskCacheBinding::EnsureStreamIO()
 107 {
 108     if (!mStreamIO) {
 109         mStreamIO = new nsDiskCacheStreamIO(this);
 110         if (!mStreamIO)  return NS_ERROR_OUT_OF_MEMORY;
 111         NS_ADDREF(mStreamIO);
 112     }
 113     return NS_OK;
 114 }
 115
 116
 117 /******************************************************************************
 118  *  nsDiskCacheBindery
 119  *
 120  *  Keeps track of bound disk cache entries to detect for collisions.
 121  *
 122  *****************************************************************************/
 123
 124 PLDHashTableOps nsDiskCacheBindery::ops =
 125 {
 126     PL_DHashAllocTable,
 127     PL_DHashFreeTable,
 128     HashKey,
 129     MatchEntry,
 130     MoveEntry,
 131     ClearEntry,
 132     PL_DHashFinalizeStub
 133 };
 134
 135
 136 nsDiskCacheBindery::nsDiskCacheBindery()
 137     : initialized(false)
 138 {
 139 }
 140
 141
 142 nsDiskCacheBindery::~nsDiskCacheBindery()
 143 {
 144     Reset();
 145 }
 146
 147
 148 nsresult
 149 nsDiskCacheBindery::Init()
 150 {
 151     nsresult rv = NS_OK;
 152     initialized = PL_DHashTableInit(&table, &ops, nullptr, sizeof(HashTableEntry), 0);
 153
 154     if (!initialized) rv = NS_ERROR_OUT_OF_MEMORY;
 155
 156     return rv;
 157 }
 158
 159 void
 160 nsDiskCacheBindery::Reset()
 161 {
 162     if (initialized) {
 163         PL_DHashTableFinish(&table);
 164         initialized = false;
 165     }
 166 }
 167
 168
 169 nsDiskCacheBinding *
 170 nsDiskCacheBindery::CreateBinding(nsCacheEntry *       entry,
 171                                   nsDiskCacheRecord *  record)
 172 {
 173     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 174     nsCOMPtr<nsISupports> data = entry->Data();
 175     if (data) {
 176         NS_ERROR("cache entry already has bind data");
 177         return nullptr;
 178     }
 179
 180     nsDiskCacheBinding * binding = new nsDiskCacheBinding(entry, record);
 181     if (!binding)  return nullptr;
 182
 183     // give ownership of the binding to the entry
 184     entry->SetData(binding);
 185
 186     // add binding to collision detection system
 187     nsresult rv = AddBinding(binding);
 188     if (NS_FAILED(rv)) {
 189         entry->SetData(nullptr);
 190         return nullptr;
 191     }
 192
 193     return binding;
 194 }
 195
 196
 197 /**
 198  *  FindActiveEntry :  to find active colliding entry so we can doom it
 199  */
 200 nsDiskCacheBinding *
 201 nsDiskCacheBindery::FindActiveBinding(uint32_t  hashNumber)
 202 {
 203     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 204     // find hash entry for key
 205     HashTableEntry * hashEntry;
 206     hashEntry =
 207       (HashTableEntry *) PL_DHashTableOperate(&table,
 208                                               (void*)(uintptr_t) hashNumber,
 209                                               PL_DHASH_LOOKUP);
 210     if (PL_DHASH_ENTRY_IS_FREE(hashEntry)) return nullptr;
 211
 212     // walk list looking for active entry
 213     NS_ASSERTION(hashEntry->mBinding, "hash entry left with no binding");
 214     nsDiskCacheBinding * binding = hashEntry->mBinding;
 215     while (binding->mCacheEntry->IsDoomed()) {
 216         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
 217         if (binding == hashEntry->mBinding)  return nullptr;
 218     }
 219     return binding;
 220 }
 221
 222
 223 /**
 224  *  AddBinding
 225  *
 226  *  Called from FindEntry() if we read an entry off of disk
 227  *      - it may already have a generation number
 228  *      - a generation number conflict is an error
 229  *
 230  *  Called from BindEntry()
 231  *      - a generation number needs to be assigned
 232  */
 233 nsresult
 234 nsDiskCacheBindery::AddBinding(nsDiskCacheBinding * binding)
 235 {
 236     NS_ENSURE_ARG_POINTER(binding);
 237     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 238
 239     // find hash entry for key
 240     HashTableEntry * hashEntry;
 241     hashEntry = (HashTableEntry *)
 242       PL_DHashTableOperate(&table,
 243                            (void *)(uintptr_t) binding->mRecord.HashNumber(),
 244                            PL_DHASH_ADD);
 245     if (!hashEntry) return NS_ERROR_OUT_OF_MEMORY;
 246
 247     if (hashEntry->mBinding == nullptr) {
 248         hashEntry->mBinding = binding;
 249         if (binding->mGeneration == 0)
 250             binding->mGeneration = 1;   // if generation uninitialized, set it to 1
 251
 252         return NS_OK;
 253     }
 254
 255
 256     // insert binding in generation order
 257     nsDiskCacheBinding * p  = hashEntry->mBinding;
 258     bool     calcGeneration = (binding->mGeneration == 0);  // do we need to calculate generation?
 259     if (calcGeneration)  binding->mGeneration = 1;          // initialize to 1 if uninitialized
 260     while (1) {
 261
 262         if (binding->mGeneration < p->mGeneration) {
 263             // here we are
 264             PR_INSERT_BEFORE(binding, p);
 265             if (hashEntry->mBinding == p)
 266                 hashEntry->mBinding = binding;
 267             break;
 268         }
 269
 270         if (binding->mGeneration == p->mGeneration) {
 271             if (calcGeneration)  ++binding->mGeneration;    // try the next generation
 272             else {
 273                 NS_ERROR("### disk cache: generations collide!");
 274                 return NS_ERROR_UNEXPECTED;
 275             }
 276         }
 277
 278         p = (nsDiskCacheBinding *)PR_NEXT_LINK(p);
 279         if (p == hashEntry->mBinding) {
 280             // end of line: insert here or die
 281             p = (nsDiskCacheBinding *)PR_PREV_LINK(p);  // back up and check generation
 282             if (p->mGeneration == 255) {
 283                 NS_WARNING("### disk cache: generation capacity at full");
 284                 return NS_ERROR_UNEXPECTED;
 285             }
 286             PR_INSERT_BEFORE(binding, hashEntry->mBinding);
 287             break;
 288         }
 289     }
 290     return NS_OK;
 291 }
 292
 293
 294 /**
 295  *  RemoveBinding :  remove binding from collision detection on deactivation
 296  */
 297 void
 298 nsDiskCacheBindery::RemoveBinding(nsDiskCacheBinding * binding)
 299 {
 300     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 301     if (!initialized)   return;
 302
 303     HashTableEntry * hashEntry;
 304     void           * key = (void *)(uintptr_t)binding->mRecord.HashNumber();
 305
 306     hashEntry = (HashTableEntry*) PL_DHashTableOperate(&table,
 307                                                        (void*)(uintptr_t) key,
 308                                                        PL_DHASH_LOOKUP);
 309     if (!PL_DHASH_ENTRY_IS_BUSY(hashEntry)) {
 310         NS_WARNING("### disk cache: binding not in hashtable!");
 311         return;
 312     }
 313
 314     if (binding == hashEntry->mBinding) {
 315         if (PR_CLIST_IS_EMPTY(binding)) {
 316             // remove this hash entry
 317             PL_DHashTableOperate(&table,
 318                                  (void*)(uintptr_t) binding->mRecord.HashNumber(),
 319                                  PL_DHASH_REMOVE);
 320             return;
 321
 322         } else {
 323             // promote next binding to head, and unlink this binding
 324             hashEntry->mBinding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
 325         }
 326     }
 327     PR_REMOVE_AND_INIT_LINK(binding);
 328 }
 329
 330
 331 /**
 332  *  ActiveBinding : PLDHashTable enumerate function to verify active bindings
 333  */
 334
 335 PLDHashOperator
 336 ActiveBinding(PLDHashTable *    table,
 337               PLDHashEntryHdr * hdr,
 338               uint32_t          number,
 339               void *            arg)
 340 {
 341     nsDiskCacheBinding * binding = ((HashTableEntry *)hdr)->mBinding;
 342     NS_ASSERTION(binding, "### disk cache binding = nullptr!");
 343
 344     nsDiskCacheBinding * head = binding;
 345     do {
 346         if (binding->IsActive()) {
 347            *((bool *)arg) = true;
 348             return PL_DHASH_STOP;
 349         }
 350
 351         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
 352     } while (binding != head);
 353
 354     return PL_DHASH_NEXT;
 355 }
 356
 357
 358 /**
 359  *  ActiveBindings : return true if any bindings have open descriptors
 360  */
 361 bool
 362 nsDiskCacheBindery::ActiveBindings()
 363 {
 364     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 365     if (!initialized) return false;
 366
 367     bool    activeBinding = false;
 368     PL_DHashTableEnumerate(&table, ActiveBinding, &activeBinding);
 369
 370     return activeBinding;
 371 }
 372
 373 struct AccumulatorArg {
 374     size_t mUsage;
 375     nsMallocSizeOfFun mMallocSizeOf;
 376 };
 377
 378 PLDHashOperator
 379 AccumulateHeapUsage(PLDHashTable *table, PLDHashEntryHdr *hdr, uint32_t number,
 380                     void *arg)
 381 {
 382     nsDiskCacheBinding *binding = ((HashTableEntry *)hdr)->mBinding;
 383     NS_ASSERTION(binding, "### disk cache binding = nsnull!");
 384
 385     AccumulatorArg *acc = (AccumulatorArg *)arg;
 386
 387     nsDiskCacheBinding *head = binding;
 388     do {
 389         acc->mUsage += acc->mMallocSizeOf(binding);
 390
 391         if (binding->mStreamIO) {
 392             acc->mUsage += binding->mStreamIO->SizeOfIncludingThis(acc->mMallocSizeOf);
 393         }
 394
 395         /* No good way to get at mDeactivateEvent internals for proper size, so
 396            we use this as an estimate. */
 397         if (binding->mDeactivateEvent) {
 398             acc->mUsage += acc->mMallocSizeOf(binding->mDeactivateEvent);
 399         }
 400
 401         binding = (nsDiskCacheBinding *)PR_NEXT_LINK(binding);
 402     } while (binding != head);
 403
 404     return PL_DHASH_NEXT;
 405 }
 406
 407 /**
 408  * SizeOfExcludingThis: return the amount of heap memory (bytes) being used by the bindery
 409  */
 410 size_t
 411 nsDiskCacheBindery::SizeOfExcludingThis(nsMallocSizeOfFun aMallocSizeOf)
 412 {
 413     NS_ASSERTION(initialized, "nsDiskCacheBindery not initialized");
 414     if (!initialized) return 0;
 415
 416     AccumulatorArg arg;
 417     arg.mUsage = 0;
 418     arg.mMallocSizeOf = aMallocSizeOf;
 419
 420     PL_DHashTableEnumerate(&table, AccumulateHeapUsage, &arg);
 421
 422     return arg.mUsage;
 423 }