Add the feature for comparing two arbitrary commits

jupyterlab_git/git.py

@@ -616,11 +616,17 @@ async def detailed_log(self, selected_hash, path):
             "modified_files": result,
         }
 
-    async def diff(self, path):
+    async def diff(self, path, previous=None, current=None):
         """
         Execute git diff command & return the result.
         """
         cmd = ["git", "diff", "--numstat", "-z"]
+
+        if previous:
+            cmd.append(previous)
+            if current:
+                cmd.append(current)
+
         code, my_output, my_error = await execute(cmd, cwd=path)
 
         if code != 0:

jupyterlab_git/handlers.py

@@ -255,10 +255,19 @@ class GitDiffHandler(GitHandler):
     @tornado.web.authenticated
     async def post(self, path: str = ""):
         """
-        POST request handler, fetches differences between commits & current working
+        POST request handler, fetches differences between two states
         tree.
         """
-        my_output = await self.git.diff(self.url2localpath(path))
+        data = self.get_json_body()
+
+        if data:
+            my_output = await self.git.diff(
+                self.url2localpath(path),
+                data.get("previous"),
+                data.get("current"),
+            )
+        else:
+            my_output = await self.git.diff(self.url2localpath(path))
 
         if my_output["code"] != 0:
             self.set_status(500)

src/components/CommitComparisonBox.tsx

@@ -0,0 +1,308 @@
+import { TranslationBundle } from '@jupyterlab/translation';
+import {
+  caretDownIcon,
+  caretRightIcon,
+  fileIcon
+} from '@jupyterlab/ui-components';
+import { CommandRegistry } from '@lumino/commands';
+import * as React from 'react';
+import { FixedSizeList, ListChildComponentProps } from 'react-window';
+import { classes } from 'typestyle';
+import { getDiffProvider } from '../model';
+import {
+  clickableSpanStyle,
+  commitComparisonBoxChangedFileListStyle,
+  commitComparisonBoxDetailStyle
+} from '../style/CommitComparisonBox';
+import {
+  changeStageButtonStyle,
+  sectionAreaStyle,
+  sectionHeaderLabelStyle
+} from '../style/GitStageStyle';
+import {
+  deletionsMadeIcon,
+  diffIcon,
+  insertionsMadeIcon
+} from '../style/icons';
+import {
+  commitClass,
+  commitDetailFileClass,
+  commitDetailHeaderClass,
+  commitOverviewNumbersClass,
+  deletionsIconClass,
+  fileListClass,
+  iconClass,
+  insertionsIconClass
+} from '../style/SinglePastCommitInfo';
+import { Git, IGitExtension } from '../tokens';
+import { ActionButton } from './ActionButton';
+import { FilePath } from './FilePath';
+
+const ITEM_HEIGHT = 24; // File list item height
+
+interface ICommitComparisonBoxHeaderProps {
+  collapsible: boolean;
+  collapsed?: boolean;
+  label?: string;
+  trans: TranslationBundle;
+  onCollapseExpand?: (event: React.MouseEvent<HTMLElement, MouseEvent>) => void;
+  onClickCancel?: (event: React.MouseEvent<HTMLElement, MouseEvent>) => void;
+}
+
+const CommitComparisonBoxHeader: React.VFC<ICommitComparisonBoxHeaderProps> = (
+  props: ICommitComparisonBoxHeaderProps
+) => {
+  return (
+    <div className={sectionAreaStyle} onClick={props.onCollapseExpand}>
+      {props.collapsible && (
+        <button className={changeStageButtonStyle}>
+          {props.collapsed ? <caretRightIcon.react /> : <caretDownIcon.react />}
+        </button>
+      )}
+      <span className={sectionHeaderLabelStyle}>{props.label}</span>
+      {props.onClickCancel && (
+        <span className={clickableSpanStyle} onClick={props.onClickCancel}>
+          {props.trans.__('Cancel')}
+        </span>
+      )}
+    </div>
+  );
+};
+
+interface ICommitComparisonBoxOverviewProps {
+  totalFiles: number;
+  totalInsertions: number;
+  totalDeletions: number;
+  trans: TranslationBundle;
+}
+
+const CommitComparisonBoxOverview: React.VFC<ICommitComparisonBoxOverviewProps> =
+  (props: ICommitComparisonBoxOverviewProps) => {
+    return (
+      <div className={commitClass}>
+        <div className={commitOverviewNumbersClass}>
+          <span title={props.trans.__('# Files Changed')}>
+            <fileIcon.react className={iconClass} tag="span" />
+            {props.totalFiles}
+          </span>
+          <span title={props.trans.__('# Insertions')}>
+            <insertionsMadeIcon.react
+              className={classes(iconClass, insertionsIconClass)}
+              tag="span"
+            />
+            {props.totalInsertions}
+          </span>
+          <span title={props.trans.__('# Deletions')}>
+            <deletionsMadeIcon.react
+              className={classes(iconClass, deletionsIconClass)}
+              tag="span"
+            />
+            {props.totalDeletions}
+          </span>
+        </div>
+      </div>
+    );
+  };
+
+interface ICommitComparisonBoxChangedFileListProps {
+  files: Git.ICommitModifiedFile[];
+  trans: TranslationBundle;
+  onOpenDiff?: (
+    filePath: string,
+    isText: boolean,
+    previousFilePath?: string
+  ) => (event: React.MouseEvent<HTMLLIElement, MouseEvent>) => void;
+}
+
+class CommitComparisonBoxChangedFileList extends React.Component<ICommitComparisonBoxChangedFileListProps> {
+  render() {
+    return (
+      <div className={commitComparisonBoxDetailStyle}>
+        <div className={commitDetailHeaderClass}>
+          {this.props.trans.__('Changed')}
+        </div>
+        {this.props.files.length > 0 && (
+          <FixedSizeList
+            className={classes(
+              commitComparisonBoxChangedFileListStyle,
+              fileListClass
+            )}
+            height={this.props.files.length * ITEM_HEIGHT}
+            innerElementType={'ul'}
+            itemCount={this.props.files.length}
+            itemData={this.props.files}
+            itemKey={(index, data) => data[index].modified_file_path}
+            itemSize={ITEM_HEIGHT}
+            style={{ overflowX: 'hidden' }}
+            width={'auto'}
+          >
+            {this._renderFile}
+          </FixedSizeList>
+        )}
+      </div>
+    );
+  }
+  /**
+   * Renders a modified file.
+   *
+   * @param props Row properties
+   * @returns React element
+   */
+  private _renderFile = (
+    props: ListChildComponentProps<Git.ICommitModifiedFile[]>
+  ): JSX.Element => {
+    const { data, index, style } = props;
+    const file = data[index];
+    const path = file.modified_file_path;
+    const previous = file.previous_file_path;
+    const flg = !!getDiffProvider(path) || !file.is_binary;
+    return (
+      <li
+        className={commitDetailFileClass}
+        onClick={this.props.onOpenDiff(path, flg, previous)}
+        style={style}
+        title={path}
+      >
+        <FilePath filepath={path} filetype={file.type} />
+        {flg ? (
+          <ActionButton
+            icon={diffIcon}
+            title={this.props.trans.__('View file changes')}
+          />
+        ) : null}
+      </li>
+    );
+  };
+}
+
+interface ICommitComparisonBoxBodyProps {
+  files: Git.ICommitModifiedFile[];
+  show: boolean;
+  trans: TranslationBundle;
+  onOpenDiff?: (
+    filePath: string,
+    isText: boolean,
+    previousFilePath?: string
+  ) => (event: React.MouseEvent<HTMLLIElement, MouseEvent>) => void;
+}
+
+const CommitComparisonBoxBody: React.VFC<ICommitComparisonBoxBodyProps> = (
+  props: ICommitComparisonBoxBodyProps
+) => {
+  const totalInsertions = props.files.reduce((acc, file) => {
+    const insertions = Number.parseInt(file.insertion, 10);
+    return acc + (Number.isNaN(insertions) ? 0 : insertions);
+  }, 0);
+  const totalDeletions = props.files.reduce((acc, file) => {
+    const deletions = Number.parseInt(file.deletion, 10);
+    return acc + (Number.isNaN(deletions) ? 0 : deletions);
+  }, 0);
+  return (
+    <React.Fragment>
+      <CommitComparisonBoxOverview
+        totalDeletions={totalDeletions}
+        totalFiles={props.files.length}
+        totalInsertions={totalInsertions}
+        trans={props.trans}
+      />
+      <CommitComparisonBoxChangedFileList
+        files={props.files}
+        onOpenDiff={props.onOpenDiff}
+        trans={props.trans}
+      />
+    </React.Fragment>
+  );
+};
+
+/**
+ * Interface describing ComparisonBox component properties.
+ */
+export interface ICommitComparisonBoxProps {
+  /**
+   * Is this collapsible?
+   */
+  collapsible: boolean;
+
+  /**
+   * Jupyter App commands registry.
+   */
+  commands: CommandRegistry;
+
+  /**
+   * The commit to compare against.
+   */
+  referenceCommit: Git.ISingleCommitInfo | null;
+
+  /**
+   * The commit to compare.
+   */
+  challengerCommit: Git.ISingleCommitInfo | null;
+
+  /**
+   * The commit comparison result.
+   */
+  changedFiles: Git.ICommitModifiedFile[] | null;
+
+  /**
+   * Header text.
+   */
+  header: string;
+
+  /**
+   * Extension data model.
+   */
+  model: IGitExtension;
+
+  /**
+   * The application language translator.
+   */
+  trans: TranslationBundle;
+
+  /**
+   * Returns a callback to be invoked on clicking cancel.
+   */
+  onCancel?: (event: React.MouseEvent<HTMLElement, MouseEvent>) => void;
+
+  /**
+   * Returns a callback to be invoked on click to display a file diff.
+   *
+   * @param filePath file path
+   * @param isText indicates whether the file supports displaying a diff
+   * @param previousFilePath when file has been relocated
+   * @returns callback
+   */
+  onOpenDiff?: (
+    filePath: string,
+    isText: boolean,
+    previousFilePath?: string
+  ) => (event: React.MouseEvent<HTMLLIElement, MouseEvent>) => void;
+}
+
+/**
+ * A component which displays a comparison between two commits.
+ */
+export const CommitComparisonBox: React.VFC<ICommitComparisonBoxProps> = (
+  props: ICommitComparisonBoxProps
+) => {
+  const [collapsed, setCollapsed] = React.useState<boolean>(false);
+  return (
+    <React.Fragment>
+      <CommitComparisonBoxHeader
+        collapsible={props.collapsible}
+        collapsed={collapsed}
+        label={props.header}
+        onCollapseExpand={() => setCollapsed(!collapsed)}
+        onClickCancel={props.onCancel}
+        trans={props.trans}
+      />
+      {!collapsed && props.changedFiles && (
+        <CommitComparisonBoxBody
+          files={props.changedFiles}
+          onOpenDiff={props.onOpenDiff}
+          show={!collapsed}
+          trans={props.trans}
+        />
+      )}
+    </React.Fragment>
+  );
+};