Change TextDocument's getText to take an optional range

TextDocument's getText() function has been changed to take an
optional range in the form of getText(range?: Range). This allows
clients to extract a substring within the document instead of the
entire document. Ranges that start at a position smaller than the
document will be adjusted to the beginning of the document. Likewise,
ranges that end beyond the length of the document will be adjusted to
end within the bounds of the document.

Signed-off-by: Remy Suen <remy.suen@gmail.com>

types/src/main.ts

@@ -1460,11 +1460,13 @@ export interface TextDocument {
 	readonly version: number;
 
 	/**
-	 * Get the text of this document.
+	 * Get the text of this document. A substring can be retrieved by
+	 * providing a range.
 	 *
+	 * @param range The interested range within the document to return.
 	 * @return The text of this document.
 	 */
-	getText(): string;
+	getText(range?: Range): string;
 
 	/**
 	 * Converts a zero-based offset to a position.
@@ -1607,7 +1609,12 @@ class FullTextDocument implements TextDocument {
 		return this._version;
 	}
 
-	public getText(): string {
+	public getText(range?: Range): string {
+		if (range) {
+			let start = this.offsetAt(range.start);
+			let end = this.offsetAt(range.end);
+			return this._content.substring(start, end);
+		}
 		return this._content;
 	}
 

types/src/test/textdocument.test.ts

@@ -5,7 +5,7 @@
 'use strict';
 
 import assert = require('assert');
-import { TextDocument, Position } from '../main';
+import { TextDocument, Range, Position } from '../main';
 
 suite('Text Document Lines Model Validator', () => {
 	function newDocument(str: string) {
@@ -62,6 +62,17 @@ suite('Text Document Lines Model Validator', () => {
 		assert.equal(newDocument(str).lineCount, 3);
 	})
 
+	test('getText(Range)', () => {
+		var str = "12345\n12345\n12345";
+		var lm = newDocument(str);
+		assert.equal(lm.getText(), str);
+		assert.equal(lm.getText(Range.create(-1, 0, 0, 5)), "12345");
+		assert.equal(lm.getText(Range.create(0, 0, 0, 5)), "12345");
+		assert.equal(lm.getText(Range.create(0, 4, 1, 1)), "5\n1");
+		assert.equal(lm.getText(Range.create(0, 4, 2, 1)), "5\n12345\n1");
+		assert.equal(lm.getText(Range.create(0, 4, 3, 1)), "5\n12345\n12345");
+		assert.equal(lm.getText(Range.create(0, 0, 3, 5)), str);
+	});
 
 	test('Invalid inputs', () => {
 		var str = "Hello World";