From 615c1adfb07b9b466173166dc2e53ace540e4b32 Mon Sep 17 00:00:00 2001 From: James O'Beirne Date: Wed, 16 Jun 2021 16:27:20 -0400 Subject: refactor: wrap CCoinsViewCursor in unique_ptr Specifically with CCoinsViewDB, if a raw cursor is allocated and not freed, a cryptic leveldb assertion failure occurs on CCoinsViewDB destruction. See: https://github.com/google/leveldb/issues/142#issuecomment-414418135 --- src/coins.cpp | 4 ++-- src/coins.h | 6 +++--- src/rpc/blockchain.cpp | 4 ++-- src/test/fuzz/coins_view.cpp | 4 ++-- src/txdb.cpp | 5 +++-- src/txdb.h | 6 +++--- 6 files changed, 15 insertions(+), 14 deletions(-) diff --git a/src/coins.cpp b/src/coins.cpp index d52851cadd..ce0b131de6 100644 --- a/src/coins.cpp +++ b/src/coins.cpp @@ -13,7 +13,7 @@ bool CCoinsView::GetCoin(const COutPoint &outpoint, Coin &coin) const { return f uint256 CCoinsView::GetBestBlock() const { return uint256(); } std::vector CCoinsView::GetHeadBlocks() const { return std::vector(); } bool CCoinsView::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return false; } -CCoinsViewCursor *CCoinsView::Cursor() const { return nullptr; } +std::unique_ptr CCoinsView::Cursor() const { return nullptr; } bool CCoinsView::HaveCoin(const COutPoint &outpoint) const { @@ -28,7 +28,7 @@ uint256 CCoinsViewBacked::GetBestBlock() const { return base->GetBestBlock(); } std::vector CCoinsViewBacked::GetHeadBlocks() const { return base->GetHeadBlocks(); } void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; } bool CCoinsViewBacked::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); } -CCoinsViewCursor *CCoinsViewBacked::Cursor() const { return base->Cursor(); } +std::unique_ptr CCoinsViewBacked::Cursor() const { return base->Cursor(); } size_t CCoinsViewBacked::EstimateSize() const { return base->EstimateSize(); } CCoinsViewCache::CCoinsViewCache(CCoinsView *baseIn) : CCoinsViewBacked(baseIn), cachedCoinsUsage(0) {} diff --git a/src/coins.h b/src/coins.h index 816b4864a3..3151a260d9 100644 --- a/src/coins.h +++ b/src/coins.h @@ -180,7 +180,7 @@ public: virtual bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock); //! Get a cursor to iterate over the whole state - virtual CCoinsViewCursor *Cursor() const; + virtual std::unique_ptr Cursor() const; //! As we use CCoinsViews polymorphically, have a virtual destructor virtual ~CCoinsView() {} @@ -204,7 +204,7 @@ public: std::vector GetHeadBlocks() const override; void SetBackend(CCoinsView &viewIn); bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override; - CCoinsViewCursor *Cursor() const override; + std::unique_ptr Cursor() const override; size_t EstimateSize() const override; }; @@ -237,7 +237,7 @@ public: uint256 GetBestBlock() const override; void SetBestBlock(const uint256 &hashBlock); bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override; - CCoinsViewCursor* Cursor() const override { + std::unique_ptr Cursor() const override { throw std::logic_error("CCoinsViewCache cursor iteration not supported."); } diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp index 63897e0e05..4d4d3fb7d0 100644 --- a/src/rpc/blockchain.cpp +++ b/src/rpc/blockchain.cpp @@ -2391,7 +2391,7 @@ static RPCHelpMan scantxoutset() LOCK(cs_main); CChainState& active_chainstate = chainman.ActiveChainstate(); active_chainstate.ForceFlushStateToDisk(); - pcursor = std::unique_ptr(active_chainstate.CoinsDB().Cursor()); + pcursor = active_chainstate.CoinsDB().Cursor(); CHECK_NONFATAL(pcursor); tip = active_chainstate.m_chain.Tip(); CHECK_NONFATAL(tip); @@ -2590,7 +2590,7 @@ UniValue CreateUTXOSnapshot(NodeContext& node, CChainState& chainstate, CAutoFil throw JSONRPCError(RPC_INTERNAL_ERROR, "Unable to read UTXO set"); } - pcursor = std::unique_ptr(chainstate.CoinsDB().Cursor()); + pcursor = chainstate.CoinsDB().Cursor(); tip = chainstate.m_blockman.LookupBlockIndex(stats.hashBlock); CHECK_NONFATAL(tip); } diff --git a/src/test/fuzz/coins_view.cpp b/src/test/fuzz/coins_view.cpp index 42f19d16c6..f452696689 100644 --- a/src/test/fuzz/coins_view.cpp +++ b/src/test/fuzz/coins_view.cpp @@ -183,8 +183,8 @@ FUZZ_TARGET_INIT(coins_view, initialize_coins_view) } { - const CCoinsViewCursor* coins_view_cursor = backend_coins_view.Cursor(); - assert(coins_view_cursor == nullptr); + std::unique_ptr coins_view_cursor = backend_coins_view.Cursor(); + assert(!coins_view_cursor); (void)backend_coins_view.EstimateSize(); (void)backend_coins_view.GetBestBlock(); (void)backend_coins_view.GetHeadBlocks(); diff --git a/src/txdb.cpp b/src/txdb.cpp index 762f71feb1..bd0e9f7317 100644 --- a/src/txdb.cpp +++ b/src/txdb.cpp @@ -168,9 +168,10 @@ bool CBlockTreeDB::ReadLastBlockFile(int &nFile) { return Read(DB_LAST_BLOCK, nFile); } -CCoinsViewCursor *CCoinsViewDB::Cursor() const +std::unique_ptr CCoinsViewDB::Cursor() const { - CCoinsViewDBCursor *i = new CCoinsViewDBCursor(const_cast(*m_db).NewIterator(), GetBestBlock()); + auto i = std::make_unique( + const_cast(*m_db).NewIterator(), GetBestBlock()); /* It seems that there are no "const iterators" for LevelDB. Since we only need read operations on it, use a const-cast to get around that restriction. */ diff --git a/src/txdb.h b/src/txdb.h index 0cf7e2f1b8..e1096ffeba 100644 --- a/src/txdb.h +++ b/src/txdb.h @@ -60,7 +60,7 @@ public: uint256 GetBestBlock() const override; std::vector GetHeadBlocks() const override; bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override; - CCoinsViewCursor *Cursor() const override; + std::unique_ptr Cursor() const override; //! Attempt to update from an older database format. Returns whether an error occurred. bool Upgrade(); @@ -74,6 +74,8 @@ public: class CCoinsViewDBCursor: public CCoinsViewCursor { public: + CCoinsViewDBCursor(CDBIterator* pcursorIn, const uint256 &hashBlockIn): + CCoinsViewCursor(hashBlockIn), pcursor(pcursorIn) {} ~CCoinsViewDBCursor() {} bool GetKey(COutPoint &key) const override; @@ -84,8 +86,6 @@ public: void Next() override; private: - CCoinsViewDBCursor(CDBIterator* pcursorIn, const uint256 &hashBlockIn): - CCoinsViewCursor(hashBlockIn), pcursor(pcursorIn) {} std::unique_ptr pcursor; std::pair keyTmp; -- cgit v1.2.3