Provide an option to insert a final newline (fixes #1666)

src/vs/workbench/api/node/mainThreadSaveParticipant.ts

@@ -7,6 +7,7 @@
 
 import { TPromise } from 'vs/base/common/winjs.base';
 import { sequence } from 'vs/base/common/async';
+import * as strings from 'vs/base/common/strings';
 import { ICodeEditorService } from 'vs/editor/common/services/codeEditorService';
 import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
 import { ISaveParticipant, ITextFileEditorModel, SaveReason } from 'vs/workbench/services/textfile/common/textfiles';
@@ -21,6 +22,7 @@ import { EditOperationsCommand } from 'vs/editor/contrib/format/common/formatCom
 import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { TextFileEditorModel } from 'vs/workbench/services/textfile/common/textFileEditorModel';
 import { ExtHostContext, ExtHostDocumentSaveParticipantShape } from './extHost.protocol';
+import { EditOperation } from 'vs/editor/common/core/editOperation';
 
 interface INamedSaveParticpant extends ISaveParticipant {
 	readonly name: string;
@@ -47,29 +49,18 @@ class TrimWhitespaceParticipant implements INamedSaveParticpant {
 		let prevSelection: Selection[] = [new Selection(1, 1, 1, 1)];
 		const cursors: IPosition[] = [];
 
-		// Find `prevSelection` in any case do ensure a good undo stack when pushing the edit
-		// Collect active cursors in `cursors` only if `isAutoSaved` to avoid having the cursors jump
-		if (model.isAttachedToEditor()) {
-			const allEditors = this.codeEditorService.listCodeEditors();
-			for (let i = 0, len = allEditors.length; i < len; i++) {
-				const editor = allEditors[i];
-				const editorModel = editor.getModel();
-
-				if (!editorModel) {
-					continue; // empty editor
-				}
-
-				if (model === editorModel) {
-					prevSelection = editor.getSelections();
-					if (isAutoSaved) {
-						cursors.push(...prevSelection.map(s => {
-							return {
-								lineNumber: s.positionLineNumber,
-								column: s.positionColumn
-							};
-						}));
-					}
-				}
+		let editor = findEditor(model, this.codeEditorService);
+		if (editor) {
+			// Find `prevSelection` in any case do ensure a good undo stack when pushing the edit
+			// Collect active cursors in `cursors` only if `isAutoSaved` to avoid having the cursors jump
+			prevSelection = editor.getSelections();
+			if (isAutoSaved) {
+				cursors.push(...prevSelection.map(s => {
+					return {
+						lineNumber: s.positionLineNumber,
+						column: s.positionColumn
+					};
+				}));
 			}
 		}
 
@@ -82,6 +73,62 @@ class TrimWhitespaceParticipant implements INamedSaveParticpant {
 	}
 }
 
+function findEditor(model: IModel, codeEditorService: ICodeEditorService): ICommonCodeEditor {
+	if (model.isAttachedToEditor()) {
+		const allEditors = codeEditorService.listCodeEditors();
+		for (let i = 0, len = allEditors.length; i < len; i++) {
+			const editor = allEditors[i];
+			const editorModel = editor.getModel();
+
+			if (!editorModel) {
+				continue; // empty editor
+			}
+
+			if (model === editorModel) {
+				return editor;
+			}
+		}
+	}
+
+	return null;
+}
+
+class FinalNewLineParticipant implements INamedSaveParticpant {
+
+	readonly name = 'FinalNewLineParticipant';
+
+	constructor(
+		@IConfigurationService private configurationService: IConfigurationService,
+		@ICodeEditorService private codeEditorService: ICodeEditorService
+	) {
+		// Nothing
+	}
+
+	public participate(model: ITextFileEditorModel, env: { reason: SaveReason }): any {
+		if (this.configurationService.lookup('files.insertFinalNewline').value) {
+			this.doInsertFinalNewLine(model.textEditorModel);
+		}
+	}
+
+	private doInsertFinalNewLine(model: IModel): void {
+		const lineCount = model.getLineCount();
+		const lastLine = model.getLineContent(lineCount);
+		const lastLineIsEmptyOrWhitespace = strings.lastNonWhitespaceIndex(lastLine) === -1;
+
+		if (lineCount <= 1 || lastLineIsEmptyOrWhitespace) {
+			return;
+		}
+
+		let prevSelection: Selection[] = [new Selection(1, 1, 1, 1)];
+		const editor = findEditor(model, this.codeEditorService);
+		if (editor) {
+			prevSelection = editor.getSelections();
+		}
+
+		model.pushEditOperations(prevSelection, [EditOperation.insert({ lineNumber: lineCount + 1, column: 0 }, model.getEOL())], (edits) => prevSelection);
+	}
+}
+
 class FormatOnSaveParticipant implements INamedSaveParticpant {
 
 	readonly name = 'FormatOnSaveParticipant';
@@ -204,6 +251,7 @@ export class SaveParticipant implements ISaveParticipant {
 
 		this._saveParticipants = [
 			instantiationService.createInstance(TrimWhitespaceParticipant),
+			instantiationService.createInstance(FinalNewLineParticipant),
 			instantiationService.createInstance(FormatOnSaveParticipant),
 			instantiationService.createInstance(ExtHostSaveParticipant)
 		];