chain: refactor input spending.

lib/blockchain/chain.js

@@ -619,12 +619,12 @@ Chain.prototype.verifyDuplicates = co(function* verifyDuplicates(block, prev, st
  */
 
 Chain.prototype.verifyInputs = co(function* verifyInputs(block, prev, state) {
+  var ret = new VerifyResult();
+  var view = new CoinView();
   var height = prev.height + 1;
   var historical = prev.isHistorical();
   var sigops = 0;
   var jobs = [];
-  var ret = new VerifyResult();
-  var view = new CoinView();
   var i, tx, valid;
 
   if (this.options.spv)
@@ -639,15 +639,13 @@ Chain.prototype.verifyInputs = co(function* verifyInputs(block, prev, state) {
 
     // Ensure tx is not double spending an output.
     if (i > 0) {
-      if (!(yield view.hasInputs(this.db, tx))) {
+      if (!(yield view.spendInputs(this.db, tx))) {
         assert(!historical, 'BUG: Spent inputs in historical data!');
         throw new VerifyError(block,
           'invalid',
           'bad-txns-inputs-missingorspent',
           100);
       }
-
-      view.spendCoins(tx);
     }
 
     // Skip everything if we're

lib/blockchain/chaindb.js

@@ -1708,7 +1708,7 @@ ChainDB.prototype.connectBlock = co(function* connectBlock(block, view) {
 
   // Write undo coins (if there are any).
   if (!view.undo.isEmpty())
-    this.put(layout.u(block.hash()), view.undo.toRaw());
+    this.put(layout.u(block.hash()), view.undo.commit());
 
   // Prune height-288 if pruning is enabled.
   yield this.pruneBlock(block);

lib/blockchain/coinview.js

@@ -105,12 +105,23 @@ CoinView.prototype.has = function has(hash, index) {
 
 CoinView.prototype.spend = function spend(hash, index) {
   var coins = this.unspent[hash];
-  var entry, undo;
 
   if (!coins)
     return null;
 
-  entry = coins.spend(index);
+  return this.spendFrom(coins, index);
+};
+
+/**
+ * Remove a coin and return it.
+ * @param {Coins} coins
+ * @param {Number} index
+ * @returns {Coin}
+ */
+
+CoinView.prototype.spendFrom = function spendFrom(coins, index) {
+  var entry = coins.spend(index);
+  var undo;
 
   if (!entry)
     return null;
@@ -191,7 +202,7 @@ CoinView.prototype.ensureInputs = co(function* ensureInputs(db, tx) {
 /**
  * Spend coins for transaction.
  * @param {TX} tx
- * @throws on missing coin
+ * @returns {Boolean}
  */
 
 CoinView.prototype.spendCoins = function spendCoins(tx) {
@@ -200,11 +211,42 @@ CoinView.prototype.spendCoins = function spendCoins(tx) {
   for (i = 0; i < tx.inputs.length; i++) {
     input = tx.inputs[i];
     prevout = input.prevout;
+
     input.coin = this.spend(prevout.hash, prevout.index);
-    assert(input.coin, 'Not all coins available.');
+
+    if (!input.coin)
+      return false;
   }
+
+  return true;
 };
 
+/**
+ * Spend coins for transaction.
+ * @param {TX} tx
+ * @returns {Boolean}
+ */
+
+CoinView.prototype.spendInputs = co(function* spendInputs(db, tx) {
+  var i, input, prevout, coins;
+
+  for (i = 0; i < tx.inputs.length; i++) {
+    input = tx.inputs[i];
+    prevout = input.prevout;
+    coins = yield this.getCoins(db, prevout.hash);
+
+    if (!coins)
+      return false;
+
+    input.coin = this.spendFrom(coins, prevout.index);
+
+    if (!input.coin)
+      return false;
+  }
+
+  return true;
+});
+
 /**
  * Convert collection to an array.
  * @returns {Coins[]}

lib/blockchain/undocoins.js

@@ -99,6 +99,17 @@ UndoCoins.prototype.isEmpty = function isEmpty() {
   return this.items.length === 0;
 };
 
+/**
+ * Render the undo coins.
+ * @returns {Buffer}
+ */
+
+UndoCoins.prototype.commit = function commit() {
+  var raw = this.toRaw();
+  this.items.length = 0;
+  return raw;
+};
+
 /**
  * Retrieve the last undo coin.
  * @returns {UndoCoin}