C++ Counter64::decrement方法代码示例

ClientCursor::~ClientCursor() {
    // Cursors must be unpinned and deregistered from their cursor manager before being deleted.
    invariant(!_operationUsingCursor);
    invariant(_disposed);

    cursorStatsOpen.decrement();
    if (isNoTimeout()) {
        cursorStatsOpenNoTimeout.decrement();
    }
}

void CursorCache::removeRef(long long id) {
    verify(id);
    stdx::lock_guard<stdx::mutex> lk(_mutex);
    _refs.erase(id);
    _refsNS.erase(id);
    cursorStatsSingleTarget.decrement();
}

void ClientCursorPin::deleteUnderlying() {
    invariant(_cursor);
    invariant(_cursor->_operationUsingCursor);
    // Note the following subtleties of this method's implementation:
    // - We must unpin the cursor before destruction, since it is an error to delete a pinned
    //   cursor.
    // - In addition, we must deregister the cursor before unpinning, since it is an
    //   error to unpin a registered cursor without holding the cursor manager lock (note that
    //   we can't simply unpin with the cursor manager lock here, since we need to guarantee
    //   exclusive ownership of the cursor when we are deleting it).

    // Note it's not safe to dereference _cursor->_cursorManager unless we know we haven't been
    // killed. If we're not locked we assume we haven't been killed because we're working with the
    // global cursor manager which never kills cursors.
    dassert(_opCtx->lockState()->isCollectionLockedForMode(_cursor->_nss.ns(), MODE_IS) ||
            _cursor->_cursorManager->isGlobalManager());

    if (!_cursor->getExecutor()->isMarkedAsKilled()) {
        _cursor->_cursorManager->deregisterCursor(_cursor);
    }

    // Make sure the cursor is disposed and unpinned before being destroyed.
    _cursor->dispose(_opCtx);
    _cursor->_operationUsingCursor = nullptr;
    delete _cursor;

    cursorStatsOpenPinned.decrement();
    _cursor = nullptr;
}

void CursorCache::removeRef(long long id) {
    verify(id);
    scoped_lock lk(_mutex);
    _refs.erase(id);
    _refsNS.erase(id);
    cursorStatsSingleTarget.decrement();
}

void ClientCursorPin::release() {
    if (!_cursor)
        return;

    // Note it's not safe to dereference _cursor->_cursorManager unless we know we haven't been
    // killed. If we're not locked we assume we haven't been killed because we're working with the
    // global cursor manager which never kills cursors.
    dassert(_opCtx->lockState()->isCollectionLockedForMode(_cursor->_nss.ns(), MODE_IS) ||
            _cursor->_cursorManager->isGlobalManager());

    invariant(_cursor->_operationUsingCursor);

    if (_cursor->getExecutor()->isMarkedAsKilled()) {
        // The ClientCursor was killed while we had it.  Therefore, it is our responsibility to
        // call dispose() and delete it.
        deleteUnderlying();
    } else {
        // Unpin the cursor under the collection cursor manager lock.
        _cursor->_cursorManager->unpin(_opCtx, _cursor);
        cursorStatsOpenPinned.decrement();
    }

    _cursor = nullptr;
}

void CursorCache::gotKillCursors(Message& m) {
    LastError::get(cc()).disable();
    DbMessage dbmessage(m);
    int n = dbmessage.pullInt();

    if (n > 2000) {
        (n < 30000 ? warning() : error()) << "receivedKillCursors, n=" << n << endl;
    }

    uassert(13286, "sent 0 cursors to kill", n >= 1);
    uassert(13287, "too many cursors to kill", n < 30000);
    massert(18632,
            str::stream() << "bad kill cursors size: " << m.dataSize(),
            m.dataSize() == 8 + (8 * n));


    ConstDataCursor cursors(dbmessage.getArray(n));

    ClientBasic* client = ClientBasic::getCurrent();
    AuthorizationSession* authSession = AuthorizationSession::get(client);
    for (int i = 0; i < n; i++) {
        long long id = cursors.readAndAdvance<LittleEndian<int64_t>>();
        LOG(_myLogLevel) << "CursorCache::gotKillCursors id: " << id << endl;

        if (!id) {
            warning() << " got cursor id of 0 to kill" << endl;
            continue;
        }

        string server;
        {
            stdx::lock_guard<stdx::mutex> lk(_mutex);

            MapSharded::iterator i = _cursors.find(id);
            if (i != _cursors.end()) {
                Status authorizationStatus =
                    authSession->checkAuthForKillCursors(NamespaceString(i->second->getNS()), id);
                audit::logKillCursorsAuthzCheck(
                    client,
                    NamespaceString(i->second->getNS()),
                    id,
                    authorizationStatus.isOK() ? ErrorCodes::OK : ErrorCodes::Unauthorized);
                if (authorizationStatus.isOK()) {
                    _cursorsMaxTimeMS.erase(i->second->getId());
                    _cursors.erase(i);
                }
                continue;
            }

            MapNormal::iterator refsIt = _refs.find(id);
            MapNormal::iterator refsNSIt = _refsNS.find(id);
            if (refsIt == _refs.end()) {
                warning() << "can't find cursor: " << id << endl;
                continue;
            }
            verify(refsNSIt != _refsNS.end());
            Status authorizationStatus =
                authSession->checkAuthForKillCursors(NamespaceString(refsNSIt->second), id);
            audit::logKillCursorsAuthzCheck(client,
                                            NamespaceString(refsNSIt->second),
                                            id,
                                            authorizationStatus.isOK() ? ErrorCodes::OK
                                                                       : ErrorCodes::Unauthorized);
            if (!authorizationStatus.isOK()) {
                continue;
            }
            server = refsIt->second;
            _refs.erase(refsIt);
            _refsNS.erase(refsNSIt);
            cursorStatsSingleTarget.decrement();
        }

        LOG(_myLogLevel) << "CursorCache::found gotKillCursors id: " << id << " server: " << server
                         << endl;

        verify(server.size());
        ScopedDbConnection conn(server);
        conn->killCursor(id);
        conn.done();
    }
}

ShardedClientCursor::~ShardedClientCursor() {
    verify(_cursor);
    delete _cursor;
    _cursor = 0;
    cursorStatsMultiTarget.decrement();
}