Block cache WIP and other fixes

- Block cache is implemented only on Windows for now
- Tracking of background jobs
- More robust sidechain syncing

src/block_cache.h

@@ -0,0 +1,41 @@
+/*
+ * This file is part of the Monero P2Pool <https://github.com/SChernykh/p2pool>
+ * Copyright (c) 2021 SChernykh <https://github.com/SChernykh>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+namespace p2pool {
+
+struct PoolBlock;
+class SideChain;
+class P2PServer;
+
+class BlockCache
+{
+public:
+	BlockCache();
+	~BlockCache();
+
+	void store(const PoolBlock& block);
+	void load_all(SideChain& side_chain, P2PServer& server);
+	void flush();
+
+private:
+	struct Impl;
+	Impl* m_impl;
+};
+
+} // namespace p2pool