* first action! (#1)

node_modules/run-queue/queue.js

@@ -0,0 +1,95 @@
+'use strict'
+module.exports = RunQueue
+
+var validate = require('aproba')
+
+function RunQueue (opts) {
+  validate('Z|O', [opts])
+  if (!opts) opts = {}
+  this.finished = false
+  this.inflight = 0
+  this.maxConcurrency = opts.maxConcurrency || 1
+  this.queued = 0
+  this.queue = []
+  this.currentPrio = null
+  this.currentQueue = null
+  this.Promise = opts.Promise || global.Promise
+  this.deferred = {}
+}
+
+RunQueue.prototype = {}
+
+RunQueue.prototype.run = function () {
+  if (arguments.length !== 0) throw new Error('RunQueue.run takes no arguments')
+  var self = this
+  var deferred = this.deferred
+  if (!deferred.promise) {
+    deferred.promise = new this.Promise(function (resolve, reject) {
+      deferred.resolve = resolve
+      deferred.reject = reject
+      self._runQueue()
+    })
+  }
+  return deferred.promise
+}
+
+RunQueue.prototype._runQueue = function () {
+  var self = this
+
+  while ((this.inflight < this.maxConcurrency) && this.queued) {
+    if (!this.currentQueue || this.currentQueue.length === 0) {
+      // wait till the current priority is entirely processed before
+      // starting a new one
+      if (this.inflight) return
+      var prios = Object.keys(this.queue)
+      for (var ii = 0; ii < prios.length; ++ii) {
+        var prioQueue = this.queue[prios[ii]]
+        if (prioQueue.length) {
+          this.currentQueue = prioQueue
+          this.currentPrio = prios[ii]
+          break
+        }
+      }
+    }
+
+    --this.queued
+    ++this.inflight
+    var next = this.currentQueue.shift()
+    var args = next.args || []
+
+    // we explicitly construct a promise here so that queue items can throw
+    // or immediately return to resolve
+    var queueEntry = new this.Promise(function (resolve) {
+      resolve(next.cmd.apply(null, args))
+    })
+
+    queueEntry.then(function () {
+      --self.inflight
+      if (self.finished) return
+      if (self.queued <= 0 && self.inflight <= 0) {
+        self.finished = true
+        self.deferred.resolve()
+      }
+      self._runQueue()
+    }, function (err) {
+      self.finished = true
+      self.deferred.reject(err)
+    })
+  }
+}
+
+RunQueue.prototype.add = function (prio, cmd, args) {
+  if (this.finished) throw new Error("Can't add to a finished queue. Create a new queue.")
+  if (Math.abs(Math.floor(prio)) !== prio) throw new Error('Priorities must be a positive integer value.')
+  validate('NFA|NFZ', [prio, cmd, args])
+  prio = Number(prio)
+  if (!this.queue[prio]) this.queue[prio] = []
+  ++this.queued
+  this.queue[prio].push({cmd: cmd, args: args})
+  // if this priority is higher than the one we're currently processing,
+  // switch back to processing its queue.
+  if (this.currentPrio > prio) {
+    this.currentQueue = this.queue[prio]
+    this.currentPrio = prio
+  }
+}