Restore blockchain from database

lib/blockchain.js

@@ -4,21 +4,19 @@ var bitcore = require('bitcore');
 var $ = bitcore.util.preconditions;
 var _ = bitcore.deps._;
 
+var NULL = '0000000000000000000000000000000000000000000000000000000000000000';
+
 function BlockChain() {
-  this.tip = '0000000000000000000000000000000000000000000000000000000000000000';
+  this.tip = NULL;
-  this.work = {
+  this.work = { NULL: 0 };
-    '0000000000000000000000000000000000000000000000000000000000000000': 0
+  this.height = { NULL: -1 };
-  };
+  this.hashByHeight = { '-1': NULL };
-  this.height = {
-    '0000000000000000000000000000000000000000000000000000000000000000': -1
-  };
-  this.hashByHeight = {
-    '-1': '0000000000000000000000000000000000000000000000000000000000000000'
-  };
   this.next = {};
   this.prev = {};
 }
 
+BlockChain.NULL = NULL;
+
 BlockChain.fromObject = function(obj) {
   var blockchain = new BlockChain();
   blockchain.tip = obj.tip;

lib/node.js

@@ -61,11 +61,14 @@ var BitcoreNode = function(bus, networkMonitor, blockService, transactionService
       return;
     }
     var blockchainChanges = self.blockchain.proposeNewBlock(block);
-    var height = self.blockchain.height[block.id];
+
-    if (height % 100 === 0) {
+    // Annotate block with extra data from the chain
-    console.log('block', block.id, 'height', height);
+    block.height = self.blockchain.height[block.id];
+    block.work = self.blockchain.work[block.id];
+
+    if (block.height % 100 === 0) {
+      console.log('block', block.id, 'height', block.height);
     }
-    block.height = height;
 
     return Promise.each(blockchainChanges.unconfirmed, function(hash) {
         return self.blockService.unconfirm(self.blockCache[hash]);

lib/services/block.js

@@ -9,6 +9,7 @@ var Transaction = bitcore.Transaction;
 var config = require('config');
 
 var errors = require('../errors');
+var BlockChain = require('../blockchain');
 
 var $ = bitcore.util.preconditions;
 var JSUtil = bitcore.util.js;
@@ -40,7 +41,7 @@ var Index = {
   next: 'nxt-', // nxt-<hash> -> hash for the next block in the main chain that is a child
   height: 'bh-', // bh-<hash> -> height (-1 means disconnected)
   tip: 'tip', // tip -> { hash: hex, height: int }, the latest tip
-  blockchain: 'chain'
+  work: 'wk-' // wk-<hash> -> amount of work for block
 };
 _.extend(Index, {
   getNextBlock: helper(Index.next),
@@ -220,29 +221,20 @@ BlockService.prototype.onBlock = function(block) {
     });
 };
 
-/**
- * Save a new block
- *
- * @param {bitcore.Block} block
- * @return {Promise<Block>} a promise of the same block, for chaining
- */
-BlockService.prototype.unconfirm = function(block) {
-  // TODO: unconfirm previous tip, confirm new tip. 
-};
-
 
 /**
  * Set a block as the current tip of the blockchain
  *
  * @param {bitcore.Block} block
+ * @param {Array=} ops
  * @return {Promise<Block>} a promise of the same block, for chaining
  */
-BlockService.prototype.confirm = function(block) {
+BlockService.prototype.confirm = function(block, ops) {
   $.checkArgument(block instanceof bitcore.Block);
 
   var self = this;
 
-  var ops = [];
+  ops = ops || [];
 
   //console.log(0);
   return Promise.try(function() {
@@ -250,7 +242,10 @@ BlockService.prototype.confirm = function(block) {
       self._setNextBlock(ops, block.header.prevHash, block);
 
       //console.log(3);
-      self._setBlockHeight(ops, block, block.height);
+      self._setBlockHeight(ops, block);
+
+      //console.log(3);
+      self._setBlockWork(ops, block);
 
       //console.log(4);
       self._setBlockByTs(ops, block);
@@ -287,11 +282,19 @@ BlockService.prototype._setNextBlock = function(ops, prevBlockHash, block) {
   });
 };
 
-BlockService.prototype._setBlockHeight = function(ops, block, height) {
+BlockService.prototype._setBlockHeight = function(ops, block) {
   ops.push({
     type: 'put',
     key: Index.getBlockHeight(block),
-    value: height
+    value: block.height
+  });
+};
+
+BlockService.prototype._setBlockWork = function(ops, block) {
+  ops.push({
+    type: 'put',
+    key: Index.getBlockWork(block),
+    value: block.work
   });
 };
 
@@ -333,6 +336,36 @@ BlockService.prototype._setBlockByTs = function(ops, block) {
   */
 };
 
+/**
+ * Unconfirm a block
+ *
+ * @param {bitcore.Block} block
+ * @param {Array=} ops
+ * @return {Promise<Block>} a promise of the same block, for chaining
+ */
+BlockService.prototype.unconfirm = function(block, ops) {
+
+  ops = ops || [];
+
+  return Promise.try(function() {
+
+    self._removeNextBlock(ops, block.header.prevHash, block);
+
+    self._unsetBlockHeight(ops, block, block.height);
+
+    self._dropBlockByTs(ops, block);
+
+    return Promise.all(block.transactions.map(function(transaction) {
+      return self.transactionService._unconfirmTransaction(ops, block, transaction);
+    }));
+
+  }).then(function() {
+
+    return self.database.batchAsync(ops);
+
+  });
+};
+
 /**
  * Retrieve the block hash that forms part of the current main chain that confirmed a given
  * transaction.
@@ -368,24 +401,57 @@ BlockService.prototype.getBlockForTransaction = function(transaction) {
 
 BlockService.prototype.getBlockchain = function() {
   var self = this;
+
   return new Promise(function(resolve, reject) {
-    self.database.getAsync(Index.blockchain).then(function(blockchain) {
+
-      blockchain = BlockChain.fromObject(JSON.parse(blockchain));
+    var blockchain = new BlockChain();
-      return resolve(blockchain);
+
-    }).catch(function(arg) {
+    var fetchBlock = function(blockHash) {
-      if (arg.message.indexOf('Key not found in database') !== -1) {
+      return Promise.all([
-        return resolve();
+        function() {
+          return self.database.getAsync(Index.getPreviousBlock(blockHash)).then(function(prevHash) {
+            blockchain.prev[blockHash] = prevHash;
+            blockchain.next[prevHash] = blockHash;
+          });
+        },
+        function() {
+          return self.database.getAsync(Index.getBlockHeight(blockHash)).then(function(height) {
+            blockchain.height[blockHash] = height;
+            blockchain.hashByHeight[height] = blockHash;
+          });
+        },
+        function() {
+          return self.database.getAsync(Index.getWork(blockHash)).then(function(work) {
+            blockchain.work[blockHash] = work;
+          });
+        }
+      ]).then(function() {
+        return blockHash;
+      });
+    };
+
+    var fetchUnlessGenesis = function(blockHash) {
+      return fetchBlock(blockHash).then(function() {
+        if (blockchain.prev[blockHash] === BlockChain.NULL) {
+          return;
+        } else {
+          return fetchUnlessGenesis(blockchain.prev[blockHash]);
+        }
+      });
+    };
+
+    return self.database.getAsync(Index.tip)
+    .catch(function(err) {
+      if (err.notFound) {
+        return undefined;
       }
-      return reject(arg);
+      throw err;
+    })
+    .then(function(tip) {
+      blockchain.tip = tip;
+      return fetchUnlessGenesis(tip);
     });
   });
 };
 
-BlockService.prototype.saveBlockchain = function(blockchain) {
-  return this.database.putAsync({
-    key: Index.blockchain,
-    value: blockchain.toJSON()
-  });
-};
-
 module.exports = BlockService;