From 4a9481e2f160001822c808c1c667d29aeb1700c0 Mon Sep 17 00:00:00 2001
From: Matteo Collina <matteo.collina@gmail.com>
Date: Tue, 17 Sep 2013 09:17:47 +0200
Subject: [PATCH] Added a basic solution based on level-sublevel.

---
 problems/queue/setup.js    |  7 ++++++
 problems/queue/solution.js | 45 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/problems/queue/setup.js b/problems/queue/setup.js
index e69de29..ddeb2fa 100644
--- a/problems/queue/setup.js
+++ b/problems/queue/setup.js
@@ -0,0 +1,7 @@
+
+function setup(run, callback) {
+  console.log(arguments)
+}
+
+module.exports       = setup
+module.exports.async = true
diff --git a/problems/queue/solution.js b/problems/queue/solution.js
index e69de29..b85741e 100644
--- a/problems/queue/solution.js
+++ b/problems/queue/solution.js
@@ -0,0 +1,45 @@
+var sublevel = require('level-sublevel')
+
+function Queue(db, name) {
+  if (!(this instanceof Queue)) return new Queue(db, name)
+
+  this._db = sublevel(db).sublevel(name)
+}
+
+module.exports = Queue
+
+Queue.prototype.push = function(element, callback) {
+  var key = (new Date()).toISOString()
+
+  this._db.put(key, element, callback)
+
+  return this;
+}
+
+Queue.prototype.shift = function(callback) {
+  var stream = this._db.createReadStream({
+                 limit: 1
+               })
+
+    , db = this._db
+
+  stream.once('data', function(data) {
+    db.del(data.key, function(err) {
+      callback(err, data.value)
+    })
+  })
+
+  stream.once('error', callback)
+
+  return this;
+}
+
+Queue.prototype.clear = function(callback) {
+  this._db.createReadStream()
+      .pipe(this._db.createWriteStream({
+              type: 'del'
+            }))
+      .on('close', callback)
+
+  return this;
+}