SQL Operations Studio Public Preview 1 (0.23) release source code

src/vs/base/common/iterator.ts

@@ -0,0 +1,106 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+export interface IIterator<T> {
+	next(): T;
+}
+
+export class ArrayIterator<T> implements IIterator<T> {
+
+	private items: T[];
+	protected start: number;
+	protected end: number;
+	protected index: number;
+
+	constructor(items: T[], start: number = 0, end: number = items.length) {
+		this.items = items;
+		this.start = start;
+		this.end = end;
+		this.index = start - 1;
+	}
+
+	public first(): T {
+		this.index = this.start;
+		return this.current();
+	}
+
+	public next(): T {
+		this.index = Math.min(this.index + 1, this.end);
+		return this.current();
+	}
+
+	protected current(): T {
+		if (this.index === this.start - 1 || this.index === this.end) {
+			return null;
+		}
+
+		return this.items[this.index];
+	}
+}
+
+export class ArrayNavigator<T> extends ArrayIterator<T> implements INavigator<T> {
+
+	constructor(items: T[], start: number = 0, end: number = items.length) {
+		super(items, start, end);
+	}
+
+	public current(): T {
+		return super.current();
+	}
+
+	public previous(): T {
+		this.index = Math.max(this.index - 1, this.start - 1);
+		return this.current();
+	}
+
+	public first(): T {
+		this.index = this.start;
+		return this.current();
+	}
+
+	public last(): T {
+		this.index = this.end - 1;
+		return this.current();
+	}
+
+	public parent(): T {
+		return null;
+	}
+
+}
+
+export class MappedIterator<T, R> implements IIterator<R> {
+
+	constructor(protected iterator: IIterator<T>, protected fn: (item: T) => R) {
+		// noop
+	}
+
+	next() { return this.fn(this.iterator.next()); }
+}
+
+export interface INavigator<T> extends IIterator<T> {
+	current(): T;
+	previous(): T;
+	parent(): T;
+	first(): T;
+	last(): T;
+	next(): T;
+}
+
+export class MappedNavigator<T, R> extends MappedIterator<T, R> implements INavigator<R> {
+
+	constructor(protected navigator: INavigator<T>, fn: (item: T) => R) {
+		super(navigator, fn);
+	}
+
+	current() { return this.fn(this.navigator.current()); }
+	previous() { return this.fn(this.navigator.previous()); }
+	parent() { return this.fn(this.navigator.parent()); }
+	first() { return this.fn(this.navigator.first()); }
+	last() { return this.fn(this.navigator.last()); }
+	next() { return this.fn(this.navigator.next()); }
+}