nsPreflightCache::CacheEntry*
nsPreflightCache::GetEntry(nsIURI* aURI,
                           nsIPrincipal* aPrincipal,
                           bool aWithCredentials,
                           bool aCreate)
{
  nsCString key;
  if (!GetCacheKey(aURI, aPrincipal, aWithCredentials, key)) {
    NS_WARNING("Invalid cache key!");
    return nsnull;
  }

  CacheEntry* entry;

  if (mTable.Get(key, &entry)) {
    // Entry already existed so just return it. Also update the LRU list.

    // Move to the head of the list.
    PR_REMOVE_LINK(entry);
    PR_INSERT_LINK(entry, &mList);

    return entry;
  }

  if (!aCreate) {
    return nsnull;
  }

  // This is a new entry, allocate and insert into the table now so that any
  // failures don't cause items to be removed from a full cache.
  entry = new CacheEntry(key);
  if (!entry) {
    NS_WARNING("Failed to allocate new cache entry!");
    return nsnull;
  }

  NS_ASSERTION(mTable.Count() <= PREFLIGHT_CACHE_SIZE,
               "Something is borked, too many entries in the cache!");

  // Now enforce the max count.
  if (mTable.Count() == PREFLIGHT_CACHE_SIZE) {
    // Try to kick out all the expired entries.
    PRTime now = PR_Now();
    mTable.Enumerate(RemoveExpiredEntries, &now);

    // If that didn't remove anything then kick out the least recently used
    // entry.
    if (mTable.Count() == PREFLIGHT_CACHE_SIZE) {
      CacheEntry* lruEntry = static_cast<CacheEntry*>(PR_LIST_TAIL(&mList));
      PR_REMOVE_LINK(lruEntry);

      // This will delete 'lruEntry'.
      mTable.Remove(lruEntry->mKey);

      NS_ASSERTION(mTable.Count() == PREFLIGHT_CACHE_SIZE - 1,
                   "Somehow tried to remove an entry that was never added!");
    }
  }
  
  if (!mTable.Put(key, entry)) {
    // Failed, clean up the new entry.
    delete entry;

    NS_WARNING("Failed to add entry to the CORS preflight cache!");
    return nsnull;
  }

  PR_INSERT_LINK(entry, &mList);

  return entry;
}
Ejemplo n.º 2
0
nsPreflightCache::CacheEntry*
nsPreflightCache::GetEntry(nsIURI* aURI,
                           nsIPrincipal* aPrincipal,
                           bool aWithCredentials,
                           bool aCreate)
{
  nsCString key;
  if (!GetCacheKey(aURI, aPrincipal, aWithCredentials, key)) {
    NS_WARNING("Invalid cache key!");
    return nullptr;
  }

  CacheEntry* entry;

  if (mTable.Get(key, &entry)) {
    // Entry already existed so just return it. Also update the LRU list.

    // Move to the head of the list.
    entry->removeFrom(mList);
    mList.insertFront(entry);

    return entry;
  }

  if (!aCreate) {
    return nullptr;
  }

  // This is a new entry, allocate and insert into the table now so that any
  // failures don't cause items to be removed from a full cache.
  entry = new CacheEntry(key);
  if (!entry) {
    NS_WARNING("Failed to allocate new cache entry!");
    return nullptr;
  }

  NS_ASSERTION(mTable.Count() <= PREFLIGHT_CACHE_SIZE,
               "Something is borked, too many entries in the cache!");

  // Now enforce the max count.
  if (mTable.Count() == PREFLIGHT_CACHE_SIZE) {
    // Try to kick out all the expired entries.
    TimeStamp now = TimeStamp::NowLoRes();
    for (auto iter = mTable.Iter(); !iter.Done(); iter.Next()) {
      nsAutoPtr<CacheEntry>& entry = iter.Data();
      entry->PurgeExpired(now);

      if (entry->mHeaders.IsEmpty() &&
          entry->mMethods.IsEmpty()) {
        // Expired, remove from the list as well as the hash table.
        entry->removeFrom(sPreflightCache->mList);
        iter.Remove();
      }
    }

    // If that didn't remove anything then kick out the least recently used
    // entry.
    if (mTable.Count() == PREFLIGHT_CACHE_SIZE) {
      CacheEntry* lruEntry = static_cast<CacheEntry*>(mList.popLast());
      MOZ_ASSERT(lruEntry);

      // This will delete 'lruEntry'.
      mTable.Remove(lruEntry->mKey);

      NS_ASSERTION(mTable.Count() == PREFLIGHT_CACHE_SIZE - 1,
                   "Somehow tried to remove an entry that was never added!");
    }
  }
  
  mTable.Put(key, entry);
  mList.insertFront(entry);

  return entry;
}