From 7b1c46e0f8aa7468fe8538ee489790dce96d2b4b Mon Sep 17 00:00:00 2001
From: Oliver Beddows <oliver@lisk.io>
Date: Mon, 1 Aug 2016 11:17:35 +0200
Subject: [PATCH] Closes #119. Adding snapshot functionality.

---
 app.js            | 16 ++++++++++++++++
 modules/loader.js |  3 ++-
 modules/round.js  | 10 ++++++++++
 sql/round.js      |  2 ++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/app.js b/app.js
index 6e70fdff945..f8d64f88afb 100644
--- a/app.js
+++ b/app.js
@@ -31,6 +31,7 @@ program
 	.option("-b, --blockchain <path>", "blockchain db path")
 	.option("-x, --peers [peers...]", "peers list")
 	.option("-l, --log <level>", "log level")
+	.option("-s, --snapshot <round>", "verify snapshot")
 	.parse(process.argv);
 
 if (program.config) {
@@ -63,6 +64,16 @@ if (program.log) {
 	appConfig.consoleLogLevel = program.log;
 }
 
+if (program.snapshot) {
+	appConfig.loading.snapshot = Math.abs(
+		Math.floor(program.snapshot)
+	);
+}
+
+if (appConfig.loading.snapshot != null) {
+	appConfig.loading.verifyOnLoading = true;
+}
+
 var config = {
 	"db": appConfig.db,
 	"modules": {
@@ -113,6 +124,11 @@ d.run(function () {
 					charset: "alphanumeric"
 				});
 
+				if (appConfig.loading.snapshot != null) {
+					appConfig.loading.verifyOnLoading = false;
+					delete appConfig.loading.snapshot;
+				}
+
 				fs.writeFile("./config.json", JSON.stringify(appConfig, null, 4), "utf8", function (err) {
 					cb(err, appConfig);
 				});
diff --git a/modules/loader.js b/modules/loader.js
index 99757c03a72..cbfaad839b6 100644
--- a/modules/loader.js
+++ b/modules/loader.js
@@ -23,9 +23,10 @@ private.syncIntervalId = null;
 // Constructor
 function Loader(cb, scope) {
 	library = scope;
-	private.genesisBlock = private.loadingLastBlock = library.genesisblock;
 	self = this;
 	self.__private = private;
+	self.__private.genesisBlock = self.__private.loadingLastBlock = library.genesisblock;
+	self.__private.snapshot = library.config.loading.snapshot;
 	private.attachApi();
 
 	setImmediate(cb, null, self);
diff --git a/modules/round.js b/modules/round.js
index 2ec57077c4c..e8607d30df9 100644
--- a/modules/round.js
+++ b/modules/round.js
@@ -24,6 +24,7 @@ function Round(cb, scope) {
 	library = scope;
 	self = this;
 	self.__private = private;
+	self.__private.snapshot = library.config.loading.snapshot;
 	setImmediate(cb, null, self);
 }
 
@@ -140,6 +141,10 @@ function RoundPromiser (scope, t) {
 				return t;
 			});
 	}
+
+	this.truncate = function () {
+		return t.none(sql.truncate, { height: scope.block.height });
+	}
 }
 
 // Public methods
@@ -273,6 +278,11 @@ Round.prototype.tick = function (block, done) {
 					delete private.rewardsByRound[round];
 					delete private.delegatesByRound[round];
 					library.bus.message("finishRound", round);
+					if (private.snapshot == round) {
+						promised.truncate().then(function () {
+							process.exit();
+						});
+					}
 				});
 			}
 		});
diff --git a/sql/round.js b/sql/round.js
index babd2b1b205..3fe04ba72ad 100644
--- a/sql/round.js
+++ b/sql/round.js
@@ -1,6 +1,8 @@
 const RoundSql = {
   flush: 'DELETE FROM mem_round WHERE "round" = (${round})::bigint;',
 
+  truncate: 'DELETE FROM blocks WHERE "height" > (${height})::bigint;',
+
   updateMissedBlocks: 'UPDATE mem_accounts SET "missedblocks" = "missedblocks" + 1 WHERE "address" IN ($1:csv);',
 
   getVotes: 'SELECT d."delegate", d."amount" FROM (SELECT m."delegate", SUM(m."amount") AS "amount", "round" FROM mem_round m GROUP BY m."delegate", m."round") AS d WHERE "round" = (${round})::bigint',