Combine CCoinsViewCache's HaveCoins and const GetCoins into AccessCoins.

The efficient version of CCoinsViewCache::GetCoins only works for known-to-exist
cache entries, requiring a separate HaveCoins call beforehand. This is
inefficient as both perform a hashtable lookup.

Replace the non-mutable GetCoins with AccessCoins, which returns a potentially-NULL
pointer. This also decreases the overloading of GetCoins.

Also replace some copying (inefficient) GetCoins calls with equivalent AccessCoins,
decreasing the copying.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/miner.cpp b/src/miner.cpp
index 96dc80a26d..d05ddbeb1f 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -167,12 +167,13 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
                     nTotalIn += mempool.mapTx[txin.prevout.hash].GetTx().vout[txin.prevout.n].nValue;
                     continue;
                 }
-                const CCoins &coins = view.GetCoins(txin.prevout.hash);
+                const CCoins* coins = view.AccessCoins(txin.prevout.hash);
+                assert(coins);
 
-                int64_t nValueIn = coins.vout[txin.prevout.n].nValue;
+                int64_t nValueIn = coins->vout[txin.prevout.n].nValue;
                 nTotalIn += nValueIn;
 
-                int nConf = pindexPrev->nHeight - coins.nHeight + 1;
+                int nConf = pindexPrev->nHeight - coins->nHeight + 1;
 
                 dPriority += (double)nValueIn * nConf;
             }