cache & freeze snippet placeholders

src/vs/editor/contrib/snippet/browser/editorSnippets.ts

@@ -67,7 +67,7 @@ class OneSnippet {
 			this._snippetDecoration = accessor.addDecoration(range, OneSnippet._decor.snippet);
 
 			// create a decoration for each placeholder
-			for (const placeholder of this._snippet.getPlaceholders()) {
+			for (const placeholder of this._snippet.placeholders) {
 				const placeholderOffset = this._snippet.offset(placeholder);
 				const placeholderLen = this._snippet.len(placeholder);
 				const range = Range.fromPositions(
@@ -83,7 +83,7 @@ class OneSnippet {
 		this._placeholderGroupsIdx = -1;
 		this._placeholderGroups = [];
 		let lastBucket: Placeholder[];
-		this._snippet.getPlaceholders().sort(Placeholder.compareByIndex).forEach(a => {
+		this._snippet.placeholders.slice(0).sort(Placeholder.compareByIndex).forEach(a => {
 			if (!lastBucket || lastBucket[0].index !== a.index) {
 				lastBucket = [a];
 				this._placeholderGroups.push(lastBucket);
@@ -147,7 +147,7 @@ class OneSnippet {
 	}
 
 	get hasPlaceholder() {
-		return this._snippet.getPlaceholders().length > 0;
+		return this._snippet.placeholders.length > 0;
 	}
 
 	get range() {

src/vs/editor/contrib/snippet/common/snippetParser.ts

@@ -222,9 +222,22 @@ export function walk(marker: Marker[], visitor: (marker: Marker) => boolean): vo
 export class TextmateSnippet {
 
 	readonly marker: Marker[];
+	readonly placeholders: Placeholder[];
 
 	constructor(marker: Marker[]) {
 		this.marker = marker;
+		this.placeholders = [];
+
+		// fill in placeholders
+		walk(marker, candidate => {
+			if (candidate instanceof Placeholder) {
+				this.placeholders.push(candidate);
+			}
+			return true;
+		});
+
+		Object.freeze(this.marker);
+		Object.freeze(this.placeholders);
 	}
 
 	offset(marker: Marker): number {
@@ -254,17 +267,6 @@ export class TextmateSnippet {
 		return ret;
 	}
 
-	getPlaceholders(): Placeholder[] {
-		const ret: Placeholder[] = [];
-		walk(this.marker, candidate => {
-			if (candidate instanceof Placeholder) {
-				ret.push(candidate);
-			}
-			return true;
-		});
-		return ret;
-	}
-
 	get text() {
 		return Marker.toString(this.marker);
 	}

src/vs/editor/contrib/snippet/test/common/snippetParser.test.ts

@@ -343,20 +343,20 @@ suite('SnippetParser', () => {
 
 	test('TextmateSnippet#placeholder', () => {
 		let snippet = SnippetParser.parse('te$1xt');
-		let placeholders = snippet.getPlaceholders();
+		let placeholders = snippet.placeholders;
 		assert.equal(placeholders.length, 1);
 
 		snippet = SnippetParser.parse('te$1xt$1');
-		placeholders = snippet.getPlaceholders();
+		placeholders = snippet.placeholders;
 		assert.equal(placeholders.length, 2);
 
 
 		snippet = SnippetParser.parse('te$1xt$2');
-		placeholders = snippet.getPlaceholders();
+		placeholders = snippet.placeholders;
 		assert.equal(placeholders.length, 2);
 
 		snippet = SnippetParser.parse('${1:bar${2:foo}bar}');
-		placeholders = snippet.getPlaceholders();
+		placeholders = snippet.placeholders;
 		assert.equal(placeholders.length, 2);
 	});
 });