Display tag similarly to branches

src/components/TagMenu.tsx

@@ -0,0 +1,309 @@
+import { Dialog, showDialog, showErrorMessage } from '@jupyterlab/apputils';
+import List from '@material-ui/core/List';
+import ListItem from '@material-ui/core/ListItem';
+import ClearIcon from '@material-ui/icons/Clear';
+import * as React from 'react';
+import { FixedSizeList, ListChildComponentProps } from 'react-window';
+import { Logger } from '../logger';
+import {
+  filterClass,
+  filterClearClass,
+  filterInputClass,
+  filterWrapperClass,
+  listItemClass,
+  listItemIconClass,
+  wrapperClass
+} from '../style/BranchMenu';
+import { tagIcon } from '../style/icons';
+import { IGitExtension, Level } from '../tokens';
+
+const CHANGES_ERR_MSG =
+  'The repository contains files with uncommitted changes. Please commit or discard these changes before switching to a tag.';
+const ITEM_HEIGHT = 24.8; // HTML element height for a single branch
+const MIN_HEIGHT = 150; // Minimal HTML element height for the tags list
+const MAX_HEIGHT = 400; // Maximal HTML element height for the tags list
+
+/**
+ * Callback invoked upon encountering an error when switching tags.
+ *
+ * @private
+ * @param error - error
+ * @param logger - the logger
+ */
+function onTagError(error: any, logger: Logger): void {
+  if (error.message.includes('following files would be overwritten')) {
+    // Empty log message to hide the executing alert
+    logger.log({
+      message: '',
+      level: Level.INFO
+    });
+    showDialog({
+      title: 'Unable to checkout tag',
+      body: (
+        <React.Fragment>
+          <p>
+            Your changes to the following files would be overwritten by
+            switching:
+          </p>
+          <List>
+            {error.message
+              .split('\n')
+              .slice(1, -3)
+              .map(renderFileName)}
+          </List>
+          <span>
+            Please commit, stash, or discard your changes before you checkout
+            tags.
+          </span>
+        </React.Fragment>
+      ),
+      buttons: [Dialog.okButton({ label: 'Dismiss' })]
+    });
+  } else {
+    logger.log({
+      level: Level.ERROR,
+      message: 'Failed to checkout tag.',
+      error
+    });
+  }
+}
+
+/**
+ * Renders a file name.
+ *
+ * @private
+ * @param filename - file name
+ * @returns React element
+ */
+function renderFileName(filename: string): React.ReactElement {
+  return <ListItem key={filename}>{filename}</ListItem>;
+}
+
+/**
+ * Interface describing component properties.
+ */
+export interface ITagMenuProps {
+  /**
+   * Boolean indicating whether branching is disabled.
+   */
+  branching: boolean;
+
+  /**
+   * Extension logger
+   */
+  logger: Logger;
+
+  /**
+   * Git extension data model.
+   */
+  model: IGitExtension;
+}
+
+/**
+ * Interface describing component state.
+ */
+export interface ITagMenuState {
+  /**
+   * Menu filter.
+   */
+  filter: string;
+
+  /**
+   * Current list of tags.
+   */
+  tags: string[];
+}
+
+/**
+ * React component for rendering a branch menu.
+ */
+export class TagMenu extends React.Component<ITagMenuProps, ITagMenuState> {
+  /**
+   * Returns a React component for rendering a branch menu.
+   *
+   * @param props - component properties
+   * @returns React component
+   */
+  constructor(props: ITagMenuProps) {
+    super(props);
+
+    this.state = {
+      filter: '',
+      tags: []
+    };
+  }
+
+  componentDidMount() {
+    this.props.model
+      .tags()
+      .then(response => {
+        this.setState({
+          tags: response.tags
+        });
+      })
+      .catch(error => {
+        console.error(error);
+        this.setState({
+          tags: []
+        });
+        showErrorMessage('Fail to get the tags.', error);
+      });
+  }
+
+  /**
+   * Renders the component.
+   *
+   * @returns React element
+   */
+  render(): React.ReactElement {
+    return (
+      <div className={wrapperClass}>
+        {this._renderFilter()}
+        {this._renderTagList()}
+      </div>
+    );
+  }
+
+  /**
+   * Renders a branch input filter.
+   *
+   * @returns React element
+   */
+  private _renderFilter(): React.ReactElement {
+    return (
+      <div className={filterWrapperClass}>
+        <div className={filterClass}>
+          <input
+            className={filterInputClass}
+            type="text"
+            onChange={this._onFilterChange}
+            value={this.state.filter}
+            placeholder="Filter"
+            title="Filter branch menu"
+          />
+          {this.state.filter ? (
+            <button className={filterClearClass}>
+              <ClearIcon
+                titleAccess="Clear the current filter"
+                fontSize="small"
+                onClick={this._resetFilter}
+              />
+            </button>
+          ) : null}
+        </div>
+      </div>
+    );
+  }
+
+  /**
+   * Renders a
+   *
+   * @returns React element
+   */
+  private _renderTagList(): React.ReactElement {
+    // Perform a "simple" filter... (TODO: consider implementing fuzzy filtering)
+    const filter = this.state.filter;
+    const tags = this.state.tags.filter(tag => !filter || tag.includes(filter));
+    return (
+      <FixedSizeList
+        height={Math.min(
+          Math.max(MIN_HEIGHT, tags.length * ITEM_HEIGHT),
+          MAX_HEIGHT
+        )}
+        itemCount={tags.length}
+        itemData={tags}
+        itemKey={(index, data) => data[index]}
+        itemSize={ITEM_HEIGHT}
+        style={{ overflowX: 'hidden', paddingTop: 0, paddingBottom: 0 }}
+        width={'auto'}
+      >
+        {this._renderItem}
+      </FixedSizeList>
+    );
+  }
+
+  /**
+   * Renders a menu item.
+   *
+   * @param props Row properties
+   * @returns React element
+   */
+  private _renderItem = (props: ListChildComponentProps): JSX.Element => {
+    const { data, index, style } = props;
+    const tag = data[index] as string;
+
+    return (
+      <ListItem
+        button
+        title={`Checkout to tag: ${tag}`}
+        className={listItemClass}
+        onClick={this._onTagClickFactory(tag)}
+        style={style}
+      >
+        <tagIcon.react className={listItemIconClass} tag="span" />
+        {tag}
+      </ListItem>
+    );
+  };
+
+  /**
+   * Callback invoked upon a change to the menu filter.
+   *
+   * @param event - event object
+   */
+  private _onFilterChange = (event: any): void => {
+    this.setState({
+      filter: event.target.value
+    });
+  };
+
+  /**
+   * Callback invoked to reset the menu filter.
+   */
+  private _resetFilter = (): void => {
+    this.setState({
+      filter: ''
+    });
+  };
+
+  /**
+   * Returns a callback which is invoked upon clicking a tag.
+   *
+   * @param branch - tag
+   * @returns callback
+   */
+  private _onTagClickFactory(tag: string) {
+    const self = this;
+    return onClick;
+
+    /**
+     * Callback invoked upon clicking a tag.
+     *
+     * @private
+     * @param event - event object
+     * @returns promise which resolves upon attempting to switch tags
+     */
+    async function onClick(): Promise<void> {
+      if (!self.props.branching) {
+        showErrorMessage('Checkout tags is disabled', CHANGES_ERR_MSG);
+        return;
+      }
+
+      self.props.logger.log({
+        level: Level.RUNNING,
+        message: 'Checking tag out...'
+      });
+
+      try {
+        await self.props.model.checkoutTag(tag);
+      } catch (err) {
+        return onTagError(err, self.props.logger);
+      }
+
+      self.props.logger.log({
+        level: Level.SUCCESS,
+        message: 'Tag checkout.'
+      });
+    }
+  }
+}