Fixes #3316 [folding] Opening a large file freezes VSCode due to folding decorations

src/vs/editor/contrib/folding/browser/folding.ts

@@ -17,17 +17,14 @@ import * as editorCommon from 'vs/editor/common/editorCommon';
 import {CommonEditorRegistry, ContextKey, EditorActionDescriptor} from 'vs/editor/common/editorCommonExtensions';
 import {ICodeEditor, IEditorMouseEvent} from 'vs/editor/browser/editorBrowser';
 import {EditorBrowserRegistry} from 'vs/editor/browser/editorBrowserExtensions';
-import {IFoldingRange, toString as rangeToString} from 'vs/editor/contrib/folding/common/foldingRange';
-import {computeRanges} from 'vs/editor/contrib/folding/common/indentFoldStrategy';
-
-let log = function(msg: string) {
-	//console.log(msg);
-};
+import {IFoldingRange} from 'vs/editor/contrib/folding/common/foldingRange';
+import {computeRanges, limitByIndent} from 'vs/editor/contrib/folding/common/indentFoldStrategy';
 
 class CollapsibleRegion {
 
 	private decorationIds: string[];
 	private _isCollapsed: boolean;
+	private _indent: number;
 
 	private _lastRange: IFoldingRange;
 
@@ -40,6 +37,10 @@ class CollapsibleRegion {
 		return this._isCollapsed;
 	}
 
+	public get indent(): number {
+		return this._indent;
+	}
+
 	public setCollapsed(isCollaped: boolean, changeAccessor:editorCommon.IModelDecorationsChangeAccessor): void {
 		this._isCollapsed = isCollaped;
 		if (this.decorationIds.length > 0) {
@@ -78,6 +79,7 @@ class CollapsibleRegion {
 	public update(newRange:IFoldingRange, model:editorCommon.IModel, changeAccessor:editorCommon.IModelDecorationsChangeAccessor): void {
 		this._lastRange = newRange;
 		this._isCollapsed = !!newRange.isCollapsed;
+		this._indent = newRange.indent;
 
 		let newDecorations : editorCommon.IModelDeltaDecoration[] = [];
 
@@ -176,7 +178,7 @@ export class FoldingController implements editorCommon.IEditorContribution {
 			if (d.isCollapsed) {
 				var range = d.getDecorationRange(model);
 				if (range) {
-					collapsedRegions.push({ startLineNumber: range.startLineNumber, endLineNumber: range.endLineNumber, isCollapsed: true});
+					collapsedRegions.push({ startLineNumber: range.startLineNumber, endLineNumber: range.endLineNumber, indent: d.indent, isCollapsed: true});
 				}
 			}
 		});
@@ -202,9 +204,7 @@ export class FoldingController implements editorCommon.IEditorContribution {
 		if (!model) {
 			return;
 		}
-
-		regions = regions.sort((r1, r2) => r1.startLineNumber - r2.startLineNumber);
-		log('imput ranges ' + regions.map(rangeToString).join(', '));
+		regions = limitByIndent(regions, 10000).sort((r1, r2) => r1.startLineNumber - r2.startLineNumber);
 
 		this.editor.changeDecorations(changeAccessor => {
 
@@ -215,19 +215,16 @@ export class FoldingController implements editorCommon.IEditorContribution {
 				let dec = this.decorations[i];
 				let decRange = dec.getDecorationRange(model);
 				if (!decRange) {
-					log('range no longer valid, was ' + dec.toString());
 					dec.dispose(changeAccessor);
 					i++;
 				} else {
 					while (k < regions.length && decRange.startLineNumber > regions[k].startLineNumber) {
-						log('new range ' + rangeToString(regions[k]));
 						newDecorations.push(new CollapsibleRegion(regions[k], model, changeAccessor));
 						k++;
 					}
 					if (k < regions.length) {
 						let currRange = regions[k];
 						if (decRange.startLineNumber < currRange.startLineNumber) {
-							log('range no longer valid, was ' + dec.toString());
 							dec.dispose(changeAccessor);
 							i++;
 						} else if (decRange.startLineNumber === currRange.startLineNumber) {
@@ -241,12 +238,10 @@ export class FoldingController implements editorCommon.IEditorContribution {
 				}
 			}
 			while (i < this.decorations.length) {
-				log('range no longer valid, was ' + this.decorations[i].toString());
 				this.decorations[i].dispose(changeAccessor);
 				i++;
 			}
 			while (k < regions.length) {
-				log('new range ' + rangeToString(regions[k]));
 				newDecorations.push(new CollapsibleRegion(regions[k], model, changeAccessor));
 				k++;
 			}

src/vs/editor/contrib/folding/common/foldingRange.ts

@@ -8,9 +8,10 @@
 export interface IFoldingRange {
 	startLineNumber:number;
 	endLineNumber:number;
+	indent:number;
 	isCollapsed?:boolean;
 }
 
 export function toString(range: IFoldingRange): string {
-	return (range ? range.startLineNumber + '/' + range.endLineNumber : 'null') + range.isCollapsed ? ' (collapsed)' : '';
+	return (range ? range.startLineNumber + '/' + range.endLineNumber : 'null') + (range.isCollapsed ? ' (collapsed)' : '') + ' - ' + range.indent;
 }
\ No newline at end of file

src/vs/editor/contrib/folding/common/indentFoldStrategy.ts

@@ -33,7 +33,7 @@ export function computeRanges(model: IModel, tabSize: number, minimumRangeSize:
 			// new folding range
 			let endLineNumber = previous.line - 1;
 			if (endLineNumber - line >= minimumRangeSize) {
-				result.push({ startLineNumber: line, endLineNumber });
+				result.push({ startLineNumber: line, endLineNumber, indent: indent });
 			}
 		}
 		if (previous.indent === indent) {
@@ -67,3 +67,31 @@ function computeIndentLevel(line: string, tabSize: number): number {
 	}
 	return indent;
 }
+
+/**
+ * Limits the number of folding ranges by removing ranges with larger indent levels
+ */
+export function limitByIndent(ranges: IFoldingRange[], maxEntries: number): IFoldingRange[] {
+	if (ranges.length <= maxEntries) {
+		return ranges;
+	}
+
+	let indentOccurrences = [];
+	ranges.forEach(r => {
+		if (r.indent < 1000) {
+			indentOccurrences[r.indent] = (indentOccurrences[r.indent] || 0) + 1;
+		}
+	});
+	let maxIndent = indentOccurrences.length;
+	for (let i = 0; i < indentOccurrences.length; i++) {
+		if (indentOccurrences[i]) {
+			maxEntries -= indentOccurrences[i];
+			if (maxEntries < 0) {
+				maxIndent = i;
+				break;
+			}
+		}
+
+	}
+	return ranges.filter(r => r.indent < maxIndent);
+}
\ No newline at end of file

src/vs/editor/contrib/folding/test/indentFold.test.ts

@@ -7,10 +7,10 @@
 import * as assert from 'assert';
 import {Model} from 'vs/editor/common/model/model';
 import {IFoldingRange} from 'vs/editor/contrib/folding/common/foldingRange';
-import {computeRanges} from 'vs/editor/contrib/folding/common/indentFoldStrategy';
+import {computeRanges, limitByIndent} from 'vs/editor/contrib/folding/common/indentFoldStrategy';
 import {DefaultEndOfLine} from 'vs/editor/common/editorCommon';
 
-suite('Folding', () => {
+suite('Indentation Folding', () => {
 	function assertRanges(lines: string[], tabSize: number, expected:IFoldingRange[]): void {
 		let model = new Model(lines.join('\n'), DefaultEndOfLine.LF, null);
 		let actual = computeRanges(model, tabSize);
@@ -19,40 +19,40 @@ suite('Folding', () => {
 		model.dispose();
 	}
 
-	function r(startLineNumber: number, endLineNumber: number): IFoldingRange {
-		return { startLineNumber, endLineNumber };
+	function r(startLineNumber: number, endLineNumber: number, indent: number): IFoldingRange {
+		return { startLineNumber, endLineNumber, indent };
 	}
 
-	test('t1', () => {
+	test('Fold one level', () => {
 		assertRanges([
 			'A',
 			'  A',
 			'  A',
 			'  A'
-		], 4, [r(1, 4)]);
+		], 4, [r(1, 4, 0)]);
 	});
 
-	test('t2', () => {
+	test('Fold two levels', () => {
 		assertRanges([
 			'A',
 			'  A',
 			'  A',
 			'    A',
 			'    A'
-		], 4, [r(1, 5), r(3, 5)] );
+		], 4, [r(1, 5, 0), r(3, 5, 2)] );
 	});
 
-	test('t3', () => {
+	test('Fold three levels', () => {
 		assertRanges([
 			'A',
 			'  A',
 			'    A',
 			'      A',
 			'A'
-		], 4, [r(1, 4), r(2, 4), r(3, 4)] );
+		], 4, [r(1, 4, 0), r(2, 4, 2), r(3, 4, 4)] );
 	});
 
-	test('t4', () => {
+	test('Fold decreasing indent', () => {
 		assertRanges([
 			'    A',
 			'  A',
@@ -60,7 +60,7 @@ suite('Folding', () => {
 		], 4, [] );
 	});
 
-	test('Java', () => {
+	test('Fold Java', () => {
 		assertRanges([
 		/* 1*/	'class A {',
 		/* 2*/	'  void foo() {',
@@ -75,10 +75,10 @@ suite('Folding', () => {
 		/*11*/	'interface B {',
 		/*12*/	'  void bar();',
 		/*13*/	'}',
-		], 4, [r(1, 9), r(2, 4), r(7, 8), r(11, 12)] );
+		], 4, [r(1, 9, 0), r(2, 4, 2), r(7, 8, 2), r(11, 12, 0)] );
 	});
 
-	test('Javadoc', () => {
+	test('Fold Javadoc', () => {
 		assertRanges([
 		/* 1*/	'/**',
 		/* 2*/	' * Comment',
@@ -87,9 +87,9 @@ suite('Folding', () => {
 		/* 5*/	'  void foo() {',
 		/* 6*/	'  }',
 		/* 7*/	'}',
-		], 4, [r(1, 3), r(4, 6)] );
+		], 4, [r(1, 3, 0), r(4, 6, 0)] );
 	});
-	test('Whitespace', () => {
+	test('Fold Whitespace', () => {
 		assertRanges([
 		/* 1*/	'class A {',
 		/* 2*/	'',
@@ -99,8 +99,20 @@ suite('Folding', () => {
 		/* 6*/	'  }',
 		/* 7*/	'      ',
 		/* 8*/	'}',
-		], 4, [r(1, 7), r(3, 5)] );
+		], 4, [r(1, 7, 0), r(3, 5, 2)] );
 	});
 
+	test('Limit By indent', () => {
+		let ranges = [r(1, 4, 0), r(3, 4, 2), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0), r(10, 15, 10), r(11, 12, 2000), r(14, 15, 2000)];
+		assert.deepEqual(limitByIndent(ranges, 8), [r(1, 4, 0), r(3, 4, 2), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0), r(10, 15, 10), r(11, 12, 2000), r(14, 15, 2000)]);
+		assert.deepEqual(limitByIndent(ranges, 7), [r(1, 4, 0), r(3, 4, 2), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0), r(10, 15, 10)]);
+		assert.deepEqual(limitByIndent(ranges, 6), [r(1, 4, 0), r(3, 4, 2), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0), r(10, 15, 10)]);
+		assert.deepEqual(limitByIndent(ranges, 5), [r(1, 4, 0), r(3, 4, 2), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0)]);
+		assert.deepEqual(limitByIndent(ranges, 4), [r(1, 4, 0), r(5, 8, 0), r(6, 7, 1), r(9, 15, 0)]);
+		assert.deepEqual(limitByIndent(ranges, 3), [r(1, 4, 0), r(5, 8, 0), r(9, 15, 0)]);
+		assert.deepEqual(limitByIndent(ranges, 2), []);
+		assert.deepEqual(limitByIndent(ranges, 1), []);
+		assert.deepEqual(limitByIndent(ranges, 0), []);
+	});
 
-});
\ No newline at end of file
+});