Optimization: Coin&& to ApplyTxInUndo

sipa · sipa · commit bd83111a0fcf · 2017-06-01T11:56:06.000-07:00
This avoids a prevector copy in ApplyTxInUndo.
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
@@ -17,7 +17,7 @@
 
 #include <boost/test/unit_test.hpp>
 
-int ApplyTxInUndo(const Coin& undo, CCoinsViewCache& view, const COutPoint& out);
+int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out);
 void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight);
 
 namespace
@@ -371,8 +371,8 @@ BOOST_AUTO_TEST_CASE(updatecoins_simulation_test)
             // restore inputs
             if (!tx.IsCoinBase()) {
                 const COutPoint &out = tx.vin[0].prevout;
-                const Coin &undoin = undo.vprevout[0];
-                ApplyTxInUndo(undoin, *(stack.back()), out);
+                Coin coin = undo.vprevout[0];
+                ApplyTxInUndo(std::move(coin), *(stack.back()), out);
             }
             // Store as a candidate for reconnection
             disconnectedids.insert(undohash);
diff --git a/src/validation.cpp b/src/validation.cpp
@@ -1256,7 +1256,7 @@ enum DisconnectResult
  * @param out The out point that corresponds to the tx input.
  * @return A DisconnectResult as an int
  */
-int ApplyTxInUndo(const Coin& undo, CCoinsViewCache& view, const COutPoint& out)
+int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out)
 {
     bool fClean = true;
 
@@ -1277,7 +1277,7 @@ int ApplyTxInUndo(const Coin& undo, CCoinsViewCache& view, const COutPoint& out)
     if (coins->IsAvailable(out.n)) fClean = false; // overwriting existing output
     if (coins->vout.size() < out.n+1)
         coins->vout.resize(out.n+1);
-    coins->vout[out.n] = undo.out;
+    coins->vout[out.n] = std::move(undo.out);
 
     return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
 }
@@ -1326,18 +1326,18 @@ static DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex*
 
         // restore inputs
         if (i > 0) { // not coinbases
-            const CTxUndo &txundo = blockUndo.vtxundo[i-1];
+            CTxUndo &txundo = blockUndo.vtxundo[i-1];
             if (txundo.vprevout.size() != tx.vin.size()) {
                 error("DisconnectBlock(): transaction and undo data inconsistent");
                 return DISCONNECT_FAILED;
             }
             for (unsigned int j = tx.vin.size(); j-- > 0;) {
                 const COutPoint &out = tx.vin[j].prevout;
-                const Coin &undo = txundo.vprevout[j];
-                int res = ApplyTxInUndo(undo, view, out);
+                int res = ApplyTxInUndo(std::move(txundo.vprevout[j]), view, out);
                 if (res == DISCONNECT_FAILED) return DISCONNECT_FAILED;
                 fClean = fClean && res != DISCONNECT_UNCLEAN;
             }
+            // At this point, all of txundo.vprevout should have been moved out.
         }
     }
 

Original file line number	Diff line number	Diff line change
`@@ -1256,7 +1256,7 @@ enum DisconnectResult`
`1256`	`1256`	`* @param out The out point that corresponds to the tx input.`
`1257`	`1257`	`* @return A DisconnectResult as an int`
`1258`	`1258`	`*/`
`1259`		`-int ApplyTxInUndo(const Coin& undo, CCoinsViewCache& view, const COutPoint& out)`
	`1259`	`+int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out)`
`1260`	`1260`	`{`
`1261`	`1261`	`bool fClean = true;`
`1262`	`1262`
`@@ -1277,7 +1277,7 @@ int ApplyTxInUndo(const Coin& undo, CCoinsViewCache& view, const COutPoint& out)`
`1277`	`1277`	`if (coins->IsAvailable(out.n)) fClean = false; // overwriting existing output`
`1278`	`1278`	`if (coins->vout.size() < out.n+1)`
`1279`	`1279`	`coins->vout.resize(out.n+1);`
`1280`		`- coins->vout[out.n] = undo.out;`
	`1280`	`+ coins->vout[out.n] = std::move(undo.out);`
`1281`	`1281`
`1282`	`1282`	`return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;`
`1283`	`1283`	`}`
`@@ -1326,18 +1326,18 @@ static DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex*`
`1326`	`1326`
`1327`	`1327`	`// restore inputs`
`1328`	`1328`	`if (i > 0) { // not coinbases`
`1329`		`- const CTxUndo &txundo = blockUndo.vtxundo[i-1];`
	`1329`	`+ CTxUndo &txundo = blockUndo.vtxundo[i-1];`
`1330`	`1330`	`if (txundo.vprevout.size() != tx.vin.size()) {`
`1331`	`1331`	`error("DisconnectBlock(): transaction and undo data inconsistent");`
`1332`	`1332`	`return DISCONNECT_FAILED;`
`1333`	`1333`	`}`
`1334`	`1334`	`for (unsigned int j = tx.vin.size(); j-- > 0;) {`
`1335`	`1335`	`const COutPoint &out = tx.vin[j].prevout;`
`1336`		`- const Coin &undo = txundo.vprevout[j];`
`1337`		`- int res = ApplyTxInUndo(undo, view, out);`
	`1336`	`+ int res = ApplyTxInUndo(std::move(txundo.vprevout[j]), view, out);`
`1338`	`1337`	`if (res == DISCONNECT_FAILED) return DISCONNECT_FAILED;`
`1339`	`1338`	`fClean = fClean && res != DISCONNECT_UNCLEAN;`
`1340`	`1339`	`}`
	`1340`	`+ // At this point, all of txundo.vprevout should have been moved out.`
`1341`	`1341`	`}`
`1342`	`1342`	`}`
`1343`	`1343`