[wallet] Move CMerkleTx functions into CWalletTx

CMerkleTx only exists as a base class for CWalletTx and for wallet file
serialization/deserialization. Move CMerkleTx methods into CWalletTx,
but leave class hierarchy and serialization logic in place.

Author: jnewbery

src/wallet/wallet.cpp

@@ -228,7 +228,7 @@ WalletCreationStatus CreateWallet(interfaces::Chain& chain, const SecureString&
 
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
-const uint256 CMerkleTx::ABANDON_HASH(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
+const uint256 CWalletTx::ABANDON_HASH(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
 
 /** @defgroup mapWallet
  *
@@ -4627,7 +4627,7 @@ CKeyPool::CKeyPool(const CPubKey& vchPubKeyIn, bool internalIn)
     m_pre_split = false;
 }
 
-void CMerkleTx::SetMerkleBranch(const uint256& block_hash, int posInBlock)
+void CWalletTx::SetMerkleBranch(const uint256& block_hash, int posInBlock)
 {
     // Update the tx's hashBlock
     hashBlock = block_hash;
@@ -4636,15 +4636,15 @@ void CMerkleTx::SetMerkleBranch(const uint256& block_hash, int posInBlock)
     nIndex = posInBlock;
 }
 
-int CMerkleTx::GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const
+int CWalletTx::GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const
 {
     if (hashUnset())
         return 0;
 
     return locked_chain.getBlockDepth(hashBlock) * (nIndex == -1 ? -1 : 1);
 }
 
-int CMerkleTx::GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const
+int CWalletTx::GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const
 {
     if (!IsCoinBase())
         return 0;
@@ -4653,7 +4653,7 @@ int CMerkleTx::GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const
     return std::max(0, (COINBASE_MATURITY+1) - chain_depth);
 }
 
-bool CMerkleTx::IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const
+bool CWalletTx::IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const
 {
     // note GetBlocksToMaturity is 0 for non-coinbase tx
     return GetBlocksToMaturity(locked_chain) > 0;

src/wallet/wallet.h

@@ -364,13 +364,13 @@ struct COutputEntry
     int vout;
 };
 
-/** A transaction with a merkle branch linking it to the block chain. */
+/** Legacy class used for deserializing vtxPrev for backwards compatibility.
+ * vtxPrev was removed in commit 93a18a3650292afbb441a47d1fa1b94aeb0164e3,
+ * but old wallet.dat files may still contain vtxPrev vectors of CMerkleTxs.
+ * These need to get deserialized for field alignment when deserializing
+ * a CWalletTx, but the deserialized values are discarded.**/
 class CMerkleTx
 {
-private:
-  /** Constant used in hashBlock to indicate tx has been abandoned */
-    static const uint256 ABANDON_HASH;
-
 public:
     CTransactionRef tx;
     uint256 hashBlock;
@@ -416,30 +416,6 @@ class CMerkleTx
         READWRITE(nIndex);
     }
 
-    void SetMerkleBranch(const uint256& block_hash, int posInBlock);
-
-    /**
-     * Return depth of transaction in blockchain:
-     * <0  : conflicts with a transaction this deep in the blockchain
-     *  0  : in memory pool, waiting to be included in a block
-     * >=1 : this many blocks deep in the main chain
-     */
-    int GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const;
-    bool IsInMainChain(interfaces::Chain::Lock& locked_chain) const { return GetDepthInMainChain(locked_chain) > 0; }
-
-    /**
-     * @return number of blocks to maturity for this transaction:
-     *  0 : is not a coinbase transaction, or is a mature coinbase transaction
-     * >0 : is a coinbase transaction which matures in this many blocks
-     */
-    int GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const;
-    bool hashUnset() const { return (hashBlock.IsNull() || hashBlock == ABANDON_HASH); }
-    bool isAbandoned() const { return (hashBlock == ABANDON_HASH); }
-    void setAbandoned() { hashBlock = ABANDON_HASH; }
-
-    const uint256& GetHash() const { return tx->GetHash(); }
-    bool IsCoinBase() const { return tx->IsCoinBase(); }
-    bool IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const;
 };
 
 //Get the marginal bytes of spending the specified output
@@ -454,6 +430,9 @@ class CWalletTx : public CMerkleTx
 private:
     const CWallet* pwallet;
 
+  /** Constant used in hashBlock to indicate tx has been abandoned */
+    static const uint256 ABANDON_HASH;
+
 public:
     /**
      * Key/value map with information about the transaction.
@@ -630,6 +609,31 @@ class CWalletTx : public CMerkleTx
     // that we still have the runtime check "AssertLockHeld(pwallet->cs_wallet)"
     // in place.
     std::set<uint256> GetConflicts() const NO_THREAD_SAFETY_ANALYSIS;
+
+    void SetMerkleBranch(const uint256& block_hash, int posInBlock);
+
+    /**
+     * Return depth of transaction in blockchain:
+     * <0  : conflicts with a transaction this deep in the blockchain
+     *  0  : in memory pool, waiting to be included in a block
+     * >=1 : this many blocks deep in the main chain
+     */
+    int GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const;
+    bool IsInMainChain(interfaces::Chain::Lock& locked_chain) const { return GetDepthInMainChain(locked_chain) > 0; }
+
+    /**
+     * @return number of blocks to maturity for this transaction:
+     *  0 : is not a coinbase transaction, or is a mature coinbase transaction
+     * >0 : is a coinbase transaction which matures in this many blocks
+     */
+    int GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const;
+    bool hashUnset() const { return (hashBlock.IsNull() || hashBlock == ABANDON_HASH); }
+    bool isAbandoned() const { return (hashBlock == ABANDON_HASH); }
+    void setAbandoned() { hashBlock = ABANDON_HASH; }
+
+    const uint256& GetHash() const { return tx->GetHash(); }
+    bool IsCoinBase() const { return tx->IsCoinBase(); }
+    bool IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const;
 };
 
 class COutput