Move GetLastStake() function from miner to miner status

This replaces the GetLastStake() free function with a method as a member
of the MinerStatus class. This function relies on the miner status state
and doesn't belong in the miner code.

Author: cyrossignol

src/gridcoin/staking/status.cpp

@@ -95,6 +95,61 @@ EfficiencyReport MinerStatus::GetEfficiencyReport() const
     return m_efficiency;
 }
 
+std::optional<CWalletTx> MinerStatus::GetLastStake(CWallet& wallet)
+{
+    CWalletTx stake_tx;
+    uint256 cached_stake_tx_hash;
+
+    {
+        LOCK(m_cs);
+        cached_stake_tx_hash = m_last_pos_tx_hash;
+    }
+
+    if (!cached_stake_tx_hash.IsNull()) {
+        if (wallet.GetTransaction(cached_stake_tx_hash, stake_tx)) {
+            return stake_tx;
+        }
+    }
+
+    const auto is_my_confirmed_stake = [](const CWalletTx& tx) {
+        return tx.IsCoinStake() && tx.IsFromMe() && tx.GetDepthInMainChain() > 0;
+    };
+
+    {
+        LOCK2(cs_main, wallet.cs_wallet);
+
+        if (wallet.mapWallet.empty()) {
+            return std::nullopt;
+        }
+
+        auto latest_iter = wallet.mapWallet.cbegin();
+
+        for (auto iter = latest_iter; iter != wallet.mapWallet.cend(); ++iter) {
+            if (iter->second.nTime > latest_iter->second.nTime
+                && is_my_confirmed_stake(iter->second))
+            {
+                latest_iter = iter;
+            }
+        }
+
+        if (latest_iter == wallet.mapWallet.cbegin()
+            && !is_my_confirmed_stake(latest_iter->second))
+        {
+            return std::nullopt;
+        }
+
+        cached_stake_tx_hash = latest_iter->first;
+        stake_tx = latest_iter->second;
+    }
+
+    {
+        LOCK(m_cs);
+        m_last_pos_tx_hash = cached_stake_tx_hash;
+    }
+
+    return stake_tx;
+}
+
 std::string MinerStatus::FormatErrors() const
 {
     return FormatErrors(m_error_flags);

src/gridcoin/staking/status.h

@@ -159,6 +159,17 @@ class MinerStatus
     //!
     EfficiencyReport GetEfficiencyReport() const;
 
+    //!
+    //! \brief Get the coinstake transaction of the last block mined by this
+    //! node.
+    //!
+    //! \param wallet Used to search for the transaction if not cached.
+    //!
+    //! \return The most recent coinstake transaction or none if the node never
+    //! mined a block before.
+    //!
+    std::optional<CWalletTx> GetLastStake(CWallet& wallet);
+
     //!
     //! \brief Get a string representation of a set of miner status errors.
     //!

src/miner.cpp

@@ -172,61 +172,6 @@ class TxPriorityCompare
     }
 };
 
-std::optional<CWalletTx> GetLastStake(CWallet& wallet)
-{
-    CWalletTx stake_tx;
-    uint256 cached_stake_tx_hash;
-
-    {
-        LOCK(g_miner_status.lock);
-        cached_stake_tx_hash = g_miner_status.m_last_pos_tx_hash;
-    }
-
-    if (!cached_stake_tx_hash.IsNull()) {
-        if (wallet.GetTransaction(cached_stake_tx_hash, stake_tx)) {
-            return stake_tx;
-        }
-    }
-
-    const auto is_my_confirmed_stake = [](const CWalletTx& tx) {
-        return tx.IsCoinStake() && tx.IsFromMe() && tx.GetDepthInMainChain() > 0;
-    };
-
-    {
-        LOCK2(cs_main, wallet.cs_wallet);
-
-        if (wallet.mapWallet.empty()) {
-            return std::nullopt;
-        }
-
-        auto latest_iter = wallet.mapWallet.cbegin();
-
-        for (auto iter = wallet.mapWallet.cbegin(); iter != wallet.mapWallet.cend(); ++iter) {
-            if (iter->second.nTime > latest_iter->second.nTime
-                && is_my_confirmed_stake(iter->second))
-            {
-                latest_iter = iter;
-            }
-        }
-
-        if (latest_iter == wallet.mapWallet.cbegin()
-            && !is_my_confirmed_stake(latest_iter->second))
-        {
-            return std::nullopt;
-        }
-
-        cached_stake_tx_hash = latest_iter->first;
-        stake_tx = latest_iter->second;
-    }
-
-    {
-        LOCK(g_miner_status.lock);
-        g_miner_status.m_last_pos_tx_hash = cached_stake_tx_hash;
-    }
-
-    return stake_tx;
-}
-
 // CreateRestOfTheBlock: collect transactions into block and fill in header
 bool CreateRestOfTheBlock(CBlock &block, CBlockIndex* pindexPrev)
 {

src/miner.h

@@ -21,8 +21,6 @@ extern unsigned int nMinerSleep;
 // It will be converted to Halfords in GetNumberOfStakeOutputs by multiplying by COIN.
 static const int64_t MIN_STAKE_SPLIT_VALUE_GRC = 800;
 
-std::optional<CWalletTx> GetLastStake(CWallet& wallet);
-
 void SplitCoinStakeOutput(CBlock &blocknew, int64_t &nReward, bool &fEnableStakeSplit, bool &fEnableSideStaking, SideStakeAlloc &vSideStakeAlloc, double &dEfficiency);
 unsigned int GetNumberOfStakeOutputs(int64_t &nValue, int64_t &nMinStakeSplitValue, double &dEfficiency);
 SideStakeAlloc GetSideStakingStatusAndAlloc();

src/rpc/mining.cpp

@@ -158,7 +158,7 @@ UniValue getlaststake(const UniValue& params, bool fHelp)
             "\n"
             "Fetch information about this wallet's last staked block.\n");
 
-    const std::optional<CWalletTx> stake_tx = GetLastStake(*pwalletMain);
+    const std::optional<CWalletTx> stake_tx = g_miner_status.GetLastStake(*pwalletMain);
 
     if (!stake_tx) {
         throw JSONRPCError(RPC_WALLET_ERROR, "No prior staked blocks found.");