add file-diff (#2398)

frontend/src/pages/file-history/main-panel.js

@@ -3,7 +3,9 @@ import PropTypes from 'prop-types';
 import Prism from 'prismjs';
 import Loading from '../../components/loading';
 import CommonToolbar from '../../components/toolbar/common-toolbar';
+import DiffViewer from '@seafile/seafile-editor/dist/diff-viewer/diff-viewer'
 import '../../css/initial-style.css';
+
 require('@seafile/seafile-editor/src/lib/code-hight-package');
 
 const contentClass = 'markdown-viewer-render-content';
@@ -33,10 +35,7 @@ class MainPanel extends React.Component {
             { 
               this.props.renderingContent ? 
                 (<div className={contentClass + ' article'}><Loading /></div>) : 
-                (<div 
-                  className={contentClass + ' article'}
-                  dangerouslySetInnerHTML={{ __html: this.props.content }}
-                />)
+                (<div className={contentClass + ' article'}><DiffViewer markdownContent={this.props.markdownContent} markdownContent1={this.props.markdownContentOld}/></div>)
             }
           </div>
         </div>

frontend/src/pages/file-history/side-panel.js

@@ -124,9 +124,9 @@ class SidePanel extends React.Component {
     this.onHideContextMenu();
   }
 
-  onHistoryItemClick =(item) => {
+  onHistoryItemClick =(item, preCommitID) => {
     this.setState({currentItem: item});
-    this.props.onHistoryItemClick(item);
+    this.props.onHistoryItemClick(item, preCommitID);
   }
 
   render() {
@@ -154,6 +154,7 @@ class SidePanel extends React.Component {
                 reloadMore={this.reloadMore}
                 currentItem={this.state.currentItem}
                 onHistoryItemClick={this.onHistoryItemClick}
+                setDiffContent={this.props.setDiffContent}
               />
             }
             <HistoryListMenu