Method emplace

src/jrd/cch.cpp:5400–5480

}

inline BufferDesc* BCBHashTable::emplace(BufferDesc* bdb, const PageNumber& page, bool remove)
{
#ifndef HASH_USE_CDS_LIST
	// bcb_syncObject should be locked in EX mode

	BufferDesc* bdb2 = find(page);
	if (!bdb2)
	{
		if (remove)
			QUE_DELETE(bdb->bdb_que);

		que& mod_que = m_chains[hash(page)];
		QUE_INSERT(mod_que, bdb->bdb_que);
	}
	return bdb2;
#else // HASH_USE_CDS_LIST

	BufferDesc* bdb2 = nullptr;
	BdbList& list = m_chains[hash(page)];

/*
	// Original libcds have no update(key, value), use this code with it

	auto ret = list.update(page, [bdb, &bdb2](bool bNew, BdbList::value_type& val)
		{
			if (bNew)
				val.second = bdb;
			else
				while (!(bdb2 = val.second))
					cds::backoff::pause();
		},
		true);
*/

	auto ret = list.update(page, bdb, [&bdb2](bool bNew, BdbList::value_type& val)
		{
			// someone might have put a page buffer in the chain concurrently, so
			// we store it for the further investigation
			if (!bNew)
				bdb2 = val.second;
		},
		true);
	fb_assert(ret.first);

	// if we have inserted the page buffer that we found (empty or oldest)
	if (bdb2 == nullptr)
	{
		fb_assert(ret.second);
#ifdef DEV_BUILD
		auto p1 = list.get(page);
		fb_assert(!p1.empty() && p1->first == page && p1->second == bdb);
#endif

		if (remove)
		{
			// remove the page buffer from old hash slot
			const PageNumber oldPage = bdb->bdb_page;
			BdbList& oldList = m_chains[hash(oldPage)];