From 5b3f6bb042da52413c53749d28dcf7311b0c0f49 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 6 Oct 2016 01:18:08 -0700
Subject: [PATCH] miner: better stopping and starting.

---
 lib/miner/miner.js      | 127 +++++++++++++++++++++++++---------------
 lib/miner/minerblock.js |   8 +--
 2 files changed, 82 insertions(+), 53 deletions(-)

diff --git a/lib/miner/miner.js b/lib/miner/miner.js
index e6aaf4f1..c66cd884 100644
--- a/lib/miner/miner.js
+++ b/lib/miner/miner.js
@@ -43,7 +43,9 @@ function Miner(options) {
   this.logger = options.logger || this.chain.logger;
 
   this.running = false;
+  this.stopping = false;
   this.attempt = null;
+  this.since = 0;
 
   this.version = -1;
   this.address = Address(options.address);
@@ -62,10 +64,6 @@ utils.inherits(Miner, AsyncObject);
 Miner.prototype._init = function _init() {
   var self = this;
 
-  this.chain.on('tip', function(tip) {
-    self.restart();
-  });
-
   this.on('block', function(block) {
     // Emit the block hex as a failsafe (in case we can't send it)
     self.logger.info('Found block: %d (%s).', block.height, block.rhash);
@@ -105,9 +103,17 @@ Miner.prototype._open = co(function* open() {
  * @returns {Promise}
  */
 
-Miner.prototype._close = function close() {
-  return Promise.resolve(null);
-};
+Miner.prototype._close = co(function* close() {
+  if (!this.running)
+    return;
+
+  if (this.stopping) {
+    yield this._onStop();
+    return;
+  }
+
+  yield this.stop();
+});
 
 /**
  * Start mining.
@@ -115,80 +121,104 @@ Miner.prototype._close = function close() {
  */
 
 Miner.prototype.start = co(function* start() {
-  var attempt, block;
+  var block;
 
   assert(!this.running, 'Miner is already running.');
 
   this.running = true;
+  this.stopping = false;
 
-  while (!block) {
-    if (!this.running)
-      return;
+  for (;;) {
+    this.attempt = null;
 
     try {
-      attempt = yield this.createBlock();
+      this.attempt = yield this.createBlock();
     } catch (e) {
-      this.running = false;
+      if (this.stopping)
+        break;
       this.emit('error', e);
-      return;
+      continue;
     }
 
-    if (!this.running)
-      return;
-
-    this.attempt = attempt;
+    if (this.stopping)
+      break;
 
     try {
-      block = yield attempt.mineAsync();
+      block = yield this.attempt.mineAsync();
     } catch (e) {
+      if (this.stopping)
+        break;
       this.emit('error', e);
-      this.restart();
-      return;
+      continue;
     }
+
+    if (this.stopping)
+      break;
+
+    if (!block)
+      continue;
+
+    try {
+      yield this.chain.add(block);
+    } catch (e) {
+      if (this.stopping)
+        break;
+      this.emit('error', e);
+      continue;
+    }
+
+    if (this.stopping)
+      break;
+
+    this.emit('block', block);
   }
 
-  try {
-    yield this.chain.add(block);
-  } catch (e) {
-    this.emit('error', e);
-    this.restart();
-    return;
-  }
-
-  this.emit('block', block);
+  this.emit('done');
 });
 
 /**
  * Stop mining.
  */
 
-Miner.prototype.stop = function stop() {
+Miner.prototype.stop = co(function* stop() {
   assert(this.running, 'Miner is not running.');
+  assert(!this.stopping, 'Miner is already stopping.');
+
+  this.stopping = true;
+
+  if (this.attempt)
+    this.attempt.destroy();
+
+  yield this._onDone();
 
   this.running = false;
+  this.stopping = false;
+  this.attempt = null;
 
-  if (this.attempt) {
-    this.attempt.destroy();
-    this.attempt = null;
-  }
-};
+  this.emit('stop');
+});
 
 /**
- * Restart miner.
+ * Wait for `done` event.
  */
 
-Miner.prototype.restart = function restart() {
+Miner.prototype._onDone = co(function* _onDone() {
   var self = this;
+  return new Promise(function(resolve, reject) {
+    self.once('done', resolve);
+  });
+});
 
-  if (!this.running)
-    return;
+/**
+ * Wait for `stop` event.
+ */
 
-  this.stop();
-
-  setTimeout(function() {
-    self.start();
-  }, 500);
-};
+Miner.prototype._onStop = co(function* _onStop() {
+  var self = this;
+  return new Promise(function(resolve, reject) {
+    self.once('stop', resolve);
+  });
+});
 
 /**
  * Create a block "attempt".
@@ -268,7 +298,10 @@ Miner.prototype.notifyEntry = function notifyEntry() {
   if (!this.attempt)
     return;
 
-  this.attempt.since++;
+  if (++this.since > 20) {
+    this.since = 0;
+    this.attempt.destroy();
+  }
 };
 
 /**
diff --git a/lib/miner/minerblock.js b/lib/miner/minerblock.js
index 3464344e..6c399828 100644
--- a/lib/miner/minerblock.js
+++ b/lib/miner/minerblock.js
@@ -61,7 +61,6 @@ function MinerBlock(options) {
   this.address = options.address;
   this.network = Network.get(options.network);
   this.destroyed = false;
-  this.since = 0;
 
   this.sigops = 0;
   this.weight = 0;
@@ -366,13 +365,10 @@ MinerBlock.prototype.findNonceAsync = co(function* findNonceAsync() {
     data = block.abbr();
     nonce = yield workers.pool.mine(data, target, min, max);
 
-    if (this.destroyed)
-      throw new Error('Miner was interrupted.');
-
     if (nonce !== -1)
       break;
 
-    if (this.since > 20)
+    if (this.destroyed)
       return nonce;
 
     block.nonce = max;
@@ -434,7 +430,7 @@ MinerBlock.prototype.mineAsync = co(function* mineAsync() {
     if (nonce !== -1)
       break;
 
-    if (this.since > 20)
+    if (this.destroyed)
       return;
 
     this.iterate();