1 files changed, 148 insertions, 0 deletions
diff --git a/node_modules/vue/src/core/observer/scheduler.js b/node_modules/vue/src/core/observer/scheduler.js
new file mode 100644
index 00000000..fce86e5f
--- /dev/null
+++ b/node_modules/vue/src/core/observer/scheduler.js
@@ -0,0 +1,148 @@
+/* @flow */
+
+import type Watcher from './watcher'
+import config from '../config'
+import { callHook, activateChildComponent } from '../instance/lifecycle'
+
+import {
+  warn,
+  nextTick,
+  devtools
+} from '../util/index'
+
+export const MAX_UPDATE_COUNT = 100
+
+const queue: Array<Watcher> = []
+const activatedChildren: Array<Component> = []
+let has: { [key: number]: ?true } = {}
+let circular: { [key: number]: number } = {}
+let waiting = false
+let flushing = false
+let index = 0
+
+/**
+ * Reset the scheduler's state.
+ */
+function resetSchedulerState () {
+  index = queue.length = activatedChildren.length = 0
+  has = {}
+  if (process.env.NODE_ENV !== 'production') {
+    circular = {}
+  }
+  waiting = flushing = false
+}
+
+/**
+ * Flush both queues and run the watchers.
+ */
+function flushSchedulerQueue () {
+  flushing = true
+  let watcher, id
+
+  // Sort queue before flush.
+  // This ensures that:
+  // 1. Components are updated from parent to child. (because parent is always
+  //    created before the child)
+  // 2. A component's user watchers are run before its render watcher (because
+  //    user watchers are created before the render watcher)
+  // 3. If a component is destroyed during a parent component's watcher run,
+  //    its watchers can be skipped.
+  queue.sort((a, b) => a.id - b.id)
+
+  // do not cache length because more watchers might be pushed
+  // as we run existing watchers
+  for (index = 0; index < queue.length; index++) {
+    watcher = queue[index]
+    id = watcher.id
+    has[id] = null
+    watcher.run()
+    // in dev build, check and stop circular updates.
+    if (process.env.NODE_ENV !== 'production' && has[id] != null) {
+      circular[id] = (circular[id] || 0) + 1
+      if (circular[id] > MAX_UPDATE_COUNT) {
+        warn(
+          'You may have an infinite update loop ' + (
+            watcher.user
+              ? `in watcher with expression "${watcher.expression}"`
+              : `in a component render function.`
+          ),
+          watcher.vm
+        )
+        break
+      }
+    }
+  }
+
+  // keep copies of post queues before resetting state
+  const activatedQueue = activatedChildren.slice()
+  const updatedQueue = queue.slice()
+
+  resetSchedulerState()
+
+  // call component updated and activated hooks
+  callActivatedHooks(activatedQueue)
+  callUpdatedHooks(updatedQueue)
+
+  // devtool hook
+  /* istanbul ignore if */
+  if (devtools && config.devtools) {
+    devtools.emit('flush')
+  }
+}
+
+function callUpdatedHooks (queue) {
+  let i = queue.length
+  while (i--) {
+    const watcher = queue[i]
+    const vm = watcher.vm
+    if (vm._watcher === watcher && vm._isMounted) {
+      callHook(vm, 'updated')
+    }
+  }
+}
+
+/**
+ * Queue a kept-alive component that was activated during patch.
+ * The queue will be processed after the entire tree has been patched.
+ */
+export function queueActivatedComponent (vm: Component) {
+  // setting _inactive to false here so that a render function can
+  // rely on checking whether it's in an inactive tree (e.g. router-view)
+  vm._inactive = false
+  activatedChildren.push(vm)
+}
+
+function callActivatedHooks (queue) {
+  for (let i = 0; i < queue.length; i++) {
+    queue[i]._inactive = true
+    activateChildComponent(queue[i], true /* true */)
+  }
+}
+
+/**
+ * Push a watcher into the watcher queue.
+ * Jobs with duplicate IDs will be skipped unless it's
+ * pushed when the queue is being flushed.
+ */
+export function queueWatcher (watcher: Watcher) {
+  const id = watcher.id
+  if (has[id] == null) {
+    has[id] = true
+    if (!flushing) {
+      queue.push(watcher)
+    } else {
+      // if already flushing, splice the watcher based on its id
+      // if already past its id, it will be run next immediately.
+      let i = queue.length - 1
+      while (i > index && queue[i].id > watcher.id) {
+        i--
+      }
+      queue.splice(i + 1, 0, watcher)
+    }
+    // queue the flush
+    if (!waiting) {
+      waiting = true
+      nextTick(flushSchedulerQueue)
+    }
+  }
+}