Fixes another off-by-one issue when diffing with caching

Refactored commands and blame annotations

src/commands/diffWithWorking.ts

@@ -0,0 +1,40 @@
+'use strict'
+import {commands, TextEditor, TextEditorEdit, Uri, window} from 'vscode';
+import {EditorCommand} from './commands';
+import {BuiltInCommands, Commands} from '../constants';
+import GitProvider from '../gitProvider';
+import * as path from 'path';
+
+export default class DiffWithWorkingCommand extends EditorCommand {
+    constructor(private git: GitProvider) {
+        super(Commands.DiffWithWorking);
+    }
+
+    execute(editor: TextEditor, edit: TextEditorEdit, uri?: Uri, repoPath?: string, sha?: string, shaUri?: Uri, line?: number) {
+        line = line || editor.selection.active.line;
+        if (!sha || GitProvider.isUncommitted(sha)) {
+            if (!(uri instanceof Uri)) {
+                if (!editor.document) return;
+                uri = editor.document.uri;
+            }
+
+            return this.git.getBlameForLine(uri.fsPath, line)
+                .catch(ex => console.error('[GitLens.DiffWithWorkingCommand]', `getBlameForLine(${line})`, ex))
+                .then(blame => {
+                    if (!blame) return;
+
+                    const commit = blame.commit;
+                    // If the line is uncommitted, find the previous commit
+                    if (commit.isUncommitted) {
+                        return commands.executeCommand(Commands.DiffWithWorking, commit.uri, commit.repoPath, commit.previousSha, commit.previousUri, blame.line.line + 1);
+                    }
+                    return commands.executeCommand(Commands.DiffWithWorking, commit.uri, commit.repoPath, commit.sha, commit.uri, line)
+                });
+        };
+
+        return this.git.getVersionedFile(shaUri.fsPath, repoPath, sha)
+            .catch(ex => console.error('[GitLens.DiffWithWorkingCommand]', 'getVersionedFile', ex))
+            .then(compare => commands.executeCommand(BuiltInCommands.Diff, Uri.file(compare), uri, `${path.basename(shaUri.fsPath)} (${sha}) ↔ ${path.basename(uri.fsPath)}`)
+                .then(() => commands.executeCommand(BuiltInCommands.RevealLine, {lineNumber: line, at: 'center'})));
+    }
+}