Merged in locks (pull request #9)

lock fragment on editor use

app/components/SimpleEditor/SimpleEditorWrapper.jsx

-import { find } from 'lodash'
+import { get, find } from 'lodash'
 import React from 'react'
 import { connect } from 'react-redux'
 import { bindActionCreators } from 'redux'
@@ -13,7 +13,10 @@ export class SimpleEditorWrapper extends React.Component {
 
     this.save = this.save.bind(this)
     this.updateComments = this.updateComments.bind(this)
+
     this._checkRights = this._checkRights.bind(this)
+    this._releaseLock = this._releaseLock.bind(this)
+    this._acquireLock = this._acquireLock.bind(this)
 
     this.state = {
       canEdit: false
@@ -28,6 +31,37 @@ export class SimpleEditorWrapper extends React.Component {
     })
 
     this._checkRights()
+    this._acquireLock()
+  }
+
+  componentDidMount () {
+    window.addEventListener('beforeunload', this._releaseLock)
+  }
+
+  componentWillUnmount () {
+    this._releaseLock()
+    window.removeEventListener('beforeunload', this._releaseLock)
+  }
+
+  _releaseLock () {
+    const { book, fragment, user } = this.props
+    const { updateFragment } = this.props.actions
+    if (get(fragment, 'lock.editor.username') && get(fragment, 'lock.editor.username') === user.username) {
+      fragment.lock = null
+    }
+    updateFragment(book, fragment)
+  }
+
+  _acquireLock () {
+    const { book, fragment, user } = this.props
+    const { updateFragment } = this.props.actions
+
+    fragment.lock = {
+      editor: {
+        username: user.username
+      }
+    }
+    updateFragment(book, fragment)
   }
 
   // componentDidUpdate () {