chain: refactor undo coins.

lib/blockchain/chaindb.js

@@ -856,27 +856,6 @@ ChainDB.prototype.hasCoins = function hasCoins(hash) {
   return this.db.has(layout.c(hash));
 };
 
-/**
- * Get a view of the existing coins necessary to verify a block.
- * @param {Block} block
- * @returns {Promise} - Returns {@link CoinView}.
- */
-
-ChainDB.prototype.getCoinView = co(function* getCoinView(block, callback) {
-  var view = new CoinView();
-  var prevout = block.getPrevout();
-  var i, prev, coins;
-
-  for (i = 0; i < prevout.length; i++) {
-    prev = prevout[i];
-    coins = yield this.getCoins(prev);
-    if (coins)
-      view.add(coins);
-  }
-
-  return view;
-});
-
 /**
  * Get coins necessary to be resurrected during a reorg.
  * @param {Hash} hash
@@ -890,32 +869,6 @@ ChainDB.prototype.getUndoCoins = co(function* getUndoCoins(hash) {
   return UndoCoins.fromRaw(data);
 });
 
-/**
- * Get a coin view containing unspent coins as
- * well as the coins to be resurrected for a reorg.
- * (Note: fills block with undo coins).
- * @param {Block} block
- * @returns {Promise} - Returns {@link CoinView}.
- */
-
-ChainDB.prototype.getUndoView = co(function* getUndoView(block) {
-  var view = yield this.getCoinView(block);
-  var undo = yield this.getUndoCoins(block.hash());
-  var index = 0;
-  var i, j, tx, input;
-
-  for (i = 1; i < block.txs.length; i++) {
-    tx = block.txs[i];
-    for (j = 0; j < tx.inputs.length; j++) {
-      input = tx.inputs[j];
-      input.coin = undo.apply(index++, view, input.prevout);
-      assert(input.coin);
-    }
-  }
-
-  return view;
-});
-
 /**
  * Retrieve a block from the database (not filled with coins).
  * @param {Hash} hash
@@ -972,11 +925,24 @@ ChainDB.prototype.getRawBlock = co(function* getRawBlock(block) {
 
 ChainDB.prototype.getFullBlock = co(function* getFullBlock(hash) {
   var block = yield this.getBlock(hash);
+  var i, j, view, undo, tx, input;
 
   if (!block)
     return;
 
-  yield this.getUndoView(block);
+  view = new CoinView();
+  undo = yield this.getUndoCoins(block.hash());
+
+  for (i = block.txs.length - 1; i > 0; i--) {
+    tx = block.txs[i];
+    for (j = tx.inputs.length - 1; j >= 0; j--) {
+      input = tx.inputs[j];
+      input.coin = undo.apply(view, input.prevout);
+    }
+  }
+
+  // Undo coins should be empty.
+  assert(undo.items.length === 0, 'Undo coins data inconsistency.');
 
   return block;
 });
@@ -1709,6 +1675,7 @@ ChainDB.prototype.connectBlock = co(function* connectBlock(block, view) {
   if (this.chain.isGenesis(block))
     return;
 
+  // Update chain state value.
   for (i = 0; i < block.txs.length; i++) {
     tx = block.txs[i];
 
@@ -1740,6 +1707,7 @@ ChainDB.prototype.connectBlock = co(function* connectBlock(block, view) {
   if (!view.undo.isEmpty())
     this.put(layout.u(block.hash()), view.undo.toRaw());
 
+  // Prune height-288 if pruning is enabled.
   yield this.pruneBlock(block);
 });
 
@@ -1750,27 +1718,21 @@ ChainDB.prototype.connectBlock = co(function* connectBlock(block, view) {
  */
 
 ChainDB.prototype.disconnectBlock = co(function* disconnectBlock(block) {
-  var i, j, view, tx, input, output;
+  var i, j, view, undo, tx, input, output;
 
   if (this.options.spv)
     return;
 
-  view = yield this.getUndoView(block);
+  view = new CoinView();
+  undo = yield this.getUndoCoins(block.hash());
 
   this.pending.disconnect(block);
 
+  // Disconnect all transactions.
   for (i = block.txs.length - 1; i >= 0; i--) {
     tx = block.txs[i];
 
-    if (i > 0) {
+    for (j = tx.outputs.length - 1; j >= 0; j--) {
-      for (j = 0; j < tx.inputs.length; j++) {
-        input = tx.inputs[j];
-        assert(input.coin);
-        this.pending.add(input.coin);
-      }
-    }
-
-    for (j = 0; j < tx.outputs.length; j++) {
       output = tx.outputs[j];
 
       if (output.script.isUnspendable())
@@ -1782,10 +1744,23 @@ ChainDB.prototype.disconnectBlock = co(function* disconnectBlock(block) {
     // Remove any created coins.
     view.removeTX(tx);
 
+    if (i > 0) {
+      yield view.ensureInputs(this, tx);
+
+      for (j = tx.inputs.length - 1; j >= 0; j--) {
+        input = tx.inputs[j];
+        input.coin = undo.apply(view, input.prevout);
+        this.pending.add(input.coin);
+      }
+    }
+
     // Remove from transaction index.
     this.unindexTX(tx);
   }
 
+  // Undo coins should be empty.
+  assert(undo.items.length === 0, 'Undo coins data inconsistency.');
+
   // Commit new coin state.
   this.saveView(view);
 

lib/blockchain/coinview.js

@@ -19,11 +19,11 @@ var UndoCoins = require('./undocoins');
  * @property {Object} coins
  */
 
-function CoinView(coins) {
+function CoinView() {
   if (!(this instanceof CoinView))
-    return new CoinView(coins);
+    return new CoinView();
 
-  this.coins = coins || {};
+  this.unspent = {};
   this.undo = new UndoCoins();
 }
 
@@ -32,8 +32,8 @@ function CoinView(coins) {
  * @param {Coins} coins
  */
 
-CoinView.prototype.add = function add(coins) {
+CoinView.prototype.addCoins = function addCoins(coins) {
-  this.coins[coins.hash] = coins;
+  this.unspent[coins.hash] = coins;
   return coins;
 };
 
@@ -43,7 +43,8 @@ CoinView.prototype.add = function add(coins) {
  */
 
 CoinView.prototype.addTX = function addTX(tx) {
-  return this.add(Coins.fromTX(tx));
+  var coins = Coins.fromTX(tx);
+  return this.addCoins(coins);
 };
 
 /**
@@ -52,9 +53,9 @@ CoinView.prototype.addTX = function addTX(tx) {
  */
 
 CoinView.prototype.removeTX = function removeTX(tx) {
-  var coins = this.addTX(tx);
+  var coins = Coins.fromTX(tx);
   coins.outputs.length = 0;
-  return coins;
+  return this.addCoins(coins);
 };
 
 /**
@@ -65,7 +66,7 @@ CoinView.prototype.removeTX = function removeTX(tx) {
  */
 
 CoinView.prototype.get = function get(hash, index) {
-  var coins = this.coins[hash];
+  var coins = this.unspent[hash];
   var entry;
 
   if (!coins)
@@ -87,7 +88,7 @@ CoinView.prototype.get = function get(hash, index) {
  */
 
 CoinView.prototype.has = function has(hash, index) {
-  var coins = this.coins[hash];
+  var coins = this.unspent[hash];
 
   if (!coins)
     return false;
@@ -103,7 +104,7 @@ CoinView.prototype.has = function has(hash, index) {
  */
 
 CoinView.prototype.spend = function spend(hash, index) {
-  var coins = this.coins[hash];
+  var coins = this.unspent[hash];
   var entry, undo;
 
   if (!coins)
@@ -133,7 +134,7 @@ CoinView.prototype.spend = function spend(hash, index) {
  */
 
 CoinView.prototype.getCoins = co(function* getCoins(db, hash) {
-  var coins = this.coins[hash];
+  var coins = this.unspent[hash];
 
   if (!coins) {
     coins = yield db.getCoins(hash);
@@ -141,7 +142,7 @@ CoinView.prototype.getCoins = co(function* getCoins(db, hash) {
     if (!coins)
       return;
 
-    this.coins[hash] = coins;
+    this.unspent[hash] = coins;
   }
 
   return coins;
@@ -172,6 +173,21 @@ CoinView.prototype.hasInputs = co(function* hasInputs(db, tx) {
   return true;
 });
 
+/**
+ * Read all input coins into unspent map.
+ * @param {ChainDB} db
+ * @param {TX} tx
+ */
+
+CoinView.prototype.ensureInputs = co(function* ensureInputs(db, tx) {
+  var i, input;
+
+  for (i = 0; i < tx.inputs.length; i++) {
+    input = tx.inputs[i];
+    yield this.getCoins(db, input.prevout.hash);
+  }
+});
+
 /**
  * Spend coins for transaction.
  * @param {TX} tx
@@ -195,13 +211,13 @@ CoinView.prototype.spendCoins = function spendCoins(tx) {
  */
 
 CoinView.prototype.toArray = function toArray() {
-  var keys = Object.keys(this.coins);
+  var keys = Object.keys(this.unspent);
   var out = [];
   var i, hash;
 
   for (i = 0; i < keys.length; i++) {
     hash = keys[i];
-    out.push(this.coins[hash]);
+    out.push(this.unspent[hash]);
   }
 
   return out;

lib/blockchain/undocoins.js

@@ -26,6 +26,9 @@ var decompress = compressor.decompress;
  */
 
 function UndoCoins() {
+  if (!(this instanceof UndoCoins))
+    return new UndoCoins();
+
   this.items = [];
 }
 
@@ -107,14 +110,13 @@ UndoCoins.prototype.top = function top() {
 
 /**
  * Re-apply undo coins to a view, effectively unspending them.
- * @param {Number} i
  * @param {CoinView} view
  * @param {Outpoint} outpoint
  * @returns {Coin}
  */
 
-UndoCoins.prototype.apply = function apply(i, view, outpoint) {
+UndoCoins.prototype.apply = function apply(view, outpoint) {
-  var undo = this.items[i];
+  var undo = this.items.pop();
   var hash = outpoint.hash;
   var index = outpoint.index;
   var coins;
@@ -124,19 +126,21 @@ UndoCoins.prototype.apply = function apply(i, view, outpoint) {
   if (undo.height !== -1) {
     coins = new Coins();
 
-    assert(!view.coins[hash]);
+    assert(!view.unspent[hash]);
-    view.coins[hash] = coins;
+    view.unspent[hash] = coins;
 
     coins.coinbase = undo.coinbase;
     coins.height = undo.height;
     coins.version = undo.version;
   } else {
-    coins = view.coins[hash];
+    coins = view.unspent[hash];
     assert(coins);
   }
 
   coins.add(index, undo.toOutput());
 
+  assert(coins.has(index));
+
   return coins.getCoin(index);
 };