From 28e2130870d4855d760581086a2bce83c4e39cce Mon Sep 17 00:00:00 2001
From: Joao Moreno <joao.moreno@microsoft.com>
Date: Fri, 22 Jun 2018 22:52:50 +0200
Subject: [PATCH] tree with iterators

---
 src/vs/base/common/tree.ts           | 26 ++++++++-
 src/vs/base/test/common/tree.test.ts | 81 ++++++++++++++--------------
 2 files changed, 65 insertions(+), 42 deletions(-)

diff --git a/src/vs/base/common/tree.ts b/src/vs/base/common/tree.ts
index 5475a8fb573..9fc081e5ef2 100644
--- a/src/vs/base/common/tree.ts
+++ b/src/vs/base/common/tree.ts
@@ -6,17 +6,37 @@
 'use strict';
 
 import { tail2, last } from 'vs/base/common/arrays';
+import { IIterator, map, iter, collect } from 'vs/base/common/iterator';
+
+export interface ITreeElement<T> {
+	readonly element: T;
+	readonly children: IIterator<ITreeElement<T>>;
+}
 
 export interface ITreeNode<T> {
 	readonly element: T;
 	readonly children: ITreeNode<T>[];
 }
 
+function asNode<T>(element: ITreeElement<T>): ITreeNode<T> {
+	return {
+		element: element.element,
+		children: collect(map(element.children, asNode))
+	};
+}
+
+function asElement<T>(element: ITreeNode<T>): ITreeElement<T> {
+	return {
+		element: element.element,
+		children: map(iter(element.children), asElement)
+	};
+}
+
 export class Tree<T> {
 
 	private root: ITreeNode<T> = { element: undefined, children: [] };
 
-	splice(start: number[], deleteCount: number, nodes: ITreeNode<T>[] = []): ITreeNode<T>[] {
+	splice(start: number[], deleteCount: number, elements: IIterator<ITreeElement<T>>): IIterator<ITreeElement<T>> {
 		if (start.length === 0) {
 			throw new Error('Invalid tree location');
 		}
@@ -24,8 +44,10 @@ export class Tree<T> {
 		const [rest, index] = tail2(start);
 		const parentPath = this.getNodePath(rest);
 		const parent = last(parentPath);
+		const nodes = collect(map(elements, asNode));
+		const deletedNodes = parent.children.splice(index, deleteCount, ...nodes);
 
-		return parent.children.splice(index, deleteCount, ...nodes);
+		return map(iter(deletedNodes), asElement);
 	}
 
 	getElement(location: number[]): T {
diff --git a/src/vs/base/test/common/tree.test.ts b/src/vs/base/test/common/tree.test.ts
index f750300dc52..9289fe8ed76 100644
--- a/src/vs/base/test/common/tree.test.ts
+++ b/src/vs/base/test/common/tree.test.ts
@@ -5,6 +5,7 @@
 
 import * as assert from 'assert';
 import { Tree } from 'vs/base/common/tree';
+import { iter } from 'vs/base/common/iterator';
 
 suite('Base Tree', () => {
 
@@ -19,11 +20,11 @@ suite('Base Tree', () => {
 	test('insert', () => {
 		const tree = new Tree<number>();
 
-		tree.splice([0], 0, [
-			{ element: 0, children: [] },
-			{ element: 1, children: [] },
-			{ element: 2, children: [] }
-		]);
+		tree.splice([0], 0, iter([
+			{ element: 0, children: iter([]) },
+			{ element: 1, children: iter([]) },
+			{ element: 2, children: iter([]) }
+		]));
 
 		const nodes = tree.getNodes();
 		assert.deepEqual(nodes.length, 3);
@@ -35,17 +36,17 @@ suite('Base Tree', () => {
 	test('deep insert', () => {
 		const tree = new Tree<number>();
 
-		tree.splice([0], 0, [
+		tree.splice([0], 0, iter([
 			{
-				element: 0, children: [
-					{ element: 10, children: [] },
-					{ element: 11, children: [] },
-					{ element: 12, children: [] },
-				]
+				element: 0, children: iter([
+					{ element: 10, children: iter([]) },
+					{ element: 11, children: iter([]) },
+					{ element: 12, children: iter([]) },
+				])
 			},
-			{ element: 1, children: [] },
-			{ element: 2, children: [] }
-		]);
+			{ element: 1, children: iter([]) },
+			{ element: 2, children: iter([]) }
+		]));
 
 		const nodes = tree.getNodes();
 		assert.deepEqual(nodes.length, 3);
@@ -61,13 +62,13 @@ suite('Base Tree', () => {
 	test('delete', () => {
 		const tree = new Tree<number>();
 
-		tree.splice([0], 0, [
-			{ element: 0, children: [] },
-			{ element: 1, children: [] },
-			{ element: 2, children: [] }
-		]);
+		tree.splice([0], 0, iter([
+			{ element: 0, children: iter([]) },
+			{ element: 1, children: iter([]) },
+			{ element: 2, children: iter([]) }
+		]));
 
-		tree.splice([0], 3, []);
+		tree.splice([0], 3, iter([]));
 
 		const nodes = tree.getNodes();
 		assert.equal(nodes.length, 0);
@@ -76,19 +77,19 @@ suite('Base Tree', () => {
 	test('nested delete', () => {
 		const tree = new Tree<number>();
 
-		tree.splice([0], 0, [
+		tree.splice([0], 0, iter([
 			{
-				element: 0, children: [
-					{ element: 10, children: [] },
-					{ element: 11, children: [] },
-					{ element: 12, children: [] },
-				]
+				element: 0, children: iter([
+					{ element: 10, children: iter([]) },
+					{ element: 11, children: iter([]) },
+					{ element: 12, children: iter([]) },
+				])
 			},
-			{ element: 1, children: [] },
-			{ element: 2, children: [] }
-		]);
+			{ element: 1, children: iter([]) },
+			{ element: 2, children: iter([]) }
+		]));
 
-		tree.splice([0, 1], 1, []);
+		tree.splice([0, 1], 1, iter([]));
 
 		const nodes = tree.getNodes();
 		assert.deepEqual(nodes.length, 3);
@@ -103,19 +104,19 @@ suite('Base Tree', () => {
 	test('deep delete', () => {
 		const tree = new Tree<number>();
 
-		tree.splice([0], 0, [
+		tree.splice([0], 0, iter([
 			{
-				element: 0, children: [
-					{ element: 10, children: [] },
-					{ element: 11, children: [] },
-					{ element: 12, children: [] },
-				]
+				element: 0, children: iter([
+					{ element: 10, children: iter([]) },
+					{ element: 11, children: iter([]) },
+					{ element: 12, children: iter([]) },
+				])
 			},
-			{ element: 1, children: [] },
-			{ element: 2, children: [] }
-		]);
+			{ element: 1, children: iter([]) },
+			{ element: 2, children: iter([]) }
+		]));
 
-		tree.splice([0], 1, []);
+		tree.splice([0], 1, iter([]));
 
 		const nodes = tree.getNodes();
 		assert.deepEqual(nodes.length, 2);