[copy link] improved 'copy link to the clipboard' (#4419)

* copy link to the clipboard, and make it shown as a link when pasted
into the seafile markdown editor

frontend/src/components/copy-to-clipboard.js

@@ -0,0 +1,45 @@
+import deselectCurrent from 'toggle-selection';
+
+function copy(text) {
+  let reselectPrevious, range, selection, mark, success = false;
+  try {
+    reselectPrevious = deselectCurrent();
+
+    range = document.createRange();
+    selection = document.getSelection();
+
+    // 'a' is for 'copy a link to seafile markdown editor'
+    mark = document.createElement('a');
+    mark.textContent = text;
+    
+    document.body.appendChild(mark);
+
+    range.selectNode(mark);
+    selection.addRange(range);
+
+    const successful = document.execCommand('copy');
+    if (!successful) {
+      //console.log('copy command was unsuccessful');
+    }
+    success = true;
+  } catch (err) {
+    // console.error('unable to copy using execCommand');
+  } finally {
+    if (selection) {
+      if (typeof selection.removeRange == 'function') {
+        selection.removeRange(range);
+      } else {
+        selection.removeAllRanges();
+      }
+    }
+
+    if (mark) {
+      document.body.removeChild(mark);
+    }
+    reselectPrevious();
+  }
+
+  return success;
+}
+
+export default copy;

frontend/src/components/dialog/internal-link-dialog.js

@@ -2,10 +2,11 @@ import React from 'react';
 import { Button, Modal, ModalHeader, ModalBody, ModalFooter } from 'reactstrap';
 import PropTypes from 'prop-types';
 import toaster from '../toast';
-import copy from '@seafile/seafile-editor/dist/utils/copy-to-clipboard';
+import copy from '../copy-to-clipboard';
 import { gettext } from '../../utils/constants';
 import { seafileAPI } from '../../utils/seafile-api';
 import { Utils } from '../../utils/utils';
+
 import '../../css/internal-link.css';
 
 const propTypes = {

frontend/src/components/dialog/internal-link.js

@@ -2,7 +2,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import { Button } from 'reactstrap';
 import toaster from '../toast';
-import copy from '@seafile/seafile-editor/dist/utils/copy-to-clipboard';
+import copy from '../copy-to-clipboard';
 import { gettext } from '../../utils/constants';
 import { seafileAPI } from '../../utils/seafile-api';
 import { Utils } from '../../utils/utils';

frontend/src/components/dialog/org-admin-invite-user-dialog.js

@@ -3,7 +3,7 @@ import PropTypes from 'prop-types';
 import { Button, Modal, ModalHeader, ModalBody, ModalFooter } from 'reactstrap';
 import { gettext } from '../../utils/constants';
 import toaster from '../toast';
-import copy from '@seafile/seafile-editor/dist//utils/copy-to-clipboard';
+import copy from '../copy-to-clipboard';
 
 const propTypes = {
   toggle: PropTypes.func.isRequired,

frontend/src/components/dialog/share-admin-link.js

@@ -1,7 +1,7 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import { Modal, ModalHeader, ModalBody, ModalFooter, Button } from 'reactstrap';
-import copy from '@seafile/seafile-editor/dist//utils/copy-to-clipboard';
+import copy from '../copy-to-clipboard';
 import { gettext } from '../../utils/constants';
 import toaster from '../../components/toast';
 

frontend/src/components/dialog/view-link-dialog.js

@@ -2,7 +2,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import { Button, Modal, ModalHeader, ModalBody, ModalFooter } from 'reactstrap';
 import toaster from '../toast';
-import copy from '@seafile/seafile-editor/dist/utils/copy-to-clipboard';
+import copy from '../copy-to-clipboard';
 import { gettext } from '../../utils/constants';
 
 const propTypes = {