debug: support variable paging

#9537

src/vs/workbench/parts/debug/common/debugModel.ts

@@ -18,20 +18,6 @@ import { Source } from 'vs/workbench/parts/debug/common/debugSource';
 const MAX_REPL_LENGTH = 10000;
 const UNKNOWN_SOURCE_LABEL = nls.localize('unknownSource', "Unknown Source");
 
-function resolveChildren(debugService: debug.IDebugService, parent: debug.IExpressionContainer): TPromise<Variable[]> {
-	const session = debugService.getActiveSession();
-	// only variables with reference > 0 have children.
-	if (!session || parent.reference <= 0) {
-		return TPromise.as([]);
-	}
-
-	return session.variables({ variablesReference: parent.reference }).then(response => {
-		return arrays.distinct(response.body.variables.filter(v => !!v), v => v.name).map(
-			v => new Variable(parent, v.variablesReference, v.name, v.value, v.type)
-		);
-	}, (e: Error) => [new Variable(parent, 0, null, e.message, null, false)]);
-}
-
 function massageValue(value: string): string {
 	return value ? value.replace(/\n/g, '\\n').replace(/\r/g, '\\r').replace(/\t/g, '\\t') : value;
 }
@@ -53,6 +39,7 @@ export function evaluateExpression(session: debug.IRawDebugSession, stackFrame:
 		if (response.body) {
 			expression.value = response.body.result;
 			expression.reference = response.body.variablesReference;
+			expression.childrenCount = response.body.totalCount;
 		}
 
 		return expression;
@@ -229,21 +216,46 @@ export class KeyValueOutputElement extends OutputElement {
 
 export abstract class ExpressionContainer implements debug.IExpressionContainer {
 
-	private children: TPromise<debug.IExpression[]>;
-	public valueChanged: boolean;
 	public static allValues: { [id: string]: string } = {};
+	// Use chunks to support variable paging #9537
+	private static CHUNK_SIZE = 100;
+
+	public valueChanged: boolean;
+	private children: TPromise<debug.IExpression[]>;
 	private _value: string;
 
-	constructor(public reference: number, private id: string, private cacheChildren: boolean) {
-		this.children = null;
+	constructor(public reference: number, private id: string, private cacheChildren: boolean, public childrenCount: number, private chunkIndex = 0) {
+		// noop
 	}
 
 	public getChildren(debugService: debug.IDebugService): TPromise<debug.IExpression[]> {
-		if (!this.cacheChildren) {
-			return resolveChildren(debugService, this);
+		if (!this.cacheChildren || !this.children) {
+			const session = debugService.getActiveSession();
+			// only variables with reference > 0 have children.
+			if (!session || this.reference <= 0) {
+				this.children = TPromise.as([]);
+			} else {
+				if (this.childrenCount > ExpressionContainer.CHUNK_SIZE) {
+					// There are a lot of children, create fake intermediate values that represent chunks #9537
+					const chunks = [];
+					const numberOfChunks = this.childrenCount / ExpressionContainer.CHUNK_SIZE;
+					for (let i = 0; i < numberOfChunks; i++) {
+						const chunkName = `${i * ExpressionContainer.CHUNK_SIZE}..${(i + 1) * ExpressionContainer.CHUNK_SIZE - 1}`;
+						chunks.push(new Variable(this, this.reference, chunkName, '', ExpressionContainer.CHUNK_SIZE, null, true, i));
+					}
+					this.children = TPromise.as(chunks);
+				} else {
+					this.children = session.variables({
+						variablesReference: this.reference,
+						start: this.chunkIndex * ExpressionContainer.CHUNK_SIZE,
+						count: ExpressionContainer.CHUNK_SIZE
+					}).then(response => {
+						return arrays.distinct(response.body.variables.filter(v => !!v), v => v.name).map(
+							v => new Variable(this, v.variablesReference, v.name, v.value, v.totalCount, v.type)
+						);
+					}, (e: Error) => [new Variable(this, 0, null, e.message, 0, null, false)]);
+				}
 			}
-		if (!this.children) {
-			this.children = resolveChildren(debugService, this);
 		}
 
 		return this.children;
@@ -271,7 +283,7 @@ export class Expression extends ExpressionContainer implements debug.IExpression
 	public available: boolean;
 
 	constructor(public name: string, cacheChildren: boolean, id = uuid.generateUuid()) {
-		super(0, id, cacheChildren);
+		super(0, id, cacheChildren, 0);
 		this.value = Expression.DEFAULT_VALUE;
 		this.available = false;
 	}
@@ -282,16 +294,16 @@ export class Variable extends ExpressionContainer implements debug.IExpression {
 	// Used to show the error message coming from the adapter when setting the value #7807
 	public errorMessage: string;
 
-	constructor(public parent: debug.IExpressionContainer, reference: number, public name: string, value: string, public type: string = null, public available = true) {
-		super(reference, `variable:${ parent.getId() }:${ name }`, true);
+	constructor(public parent: debug.IExpressionContainer, reference: number, public name: string, value: string, childrenCount: number, public type: string = null, public available = true, chunkIndex = 0) {
+		super(reference, `variable:${ parent.getId() }:${ name }`, true, childrenCount, chunkIndex);
 		this.value = massageValue(value);
 	}
 }
 
 export class Scope extends ExpressionContainer implements debug.IScope {
 
-	constructor(private threadId: number, public name: string, reference: number, public expensive: boolean) {
-		super(reference, `scope:${threadId}:${name}:${reference}`, true);
+	constructor(private threadId: number, public name: string, reference: number, public expensive: boolean, childrenCount: number) {
+		super(reference, `scope:${threadId}:${name}:${reference}`, true, childrenCount);
 	}
 }
 
@@ -310,7 +322,7 @@ export class StackFrame implements debug.IStackFrame {
 	public getScopes(debugService: debug.IDebugService): TPromise<debug.IScope[]> {
 		if (!this.scopes) {
 			this.scopes = debugService.getActiveSession().scopes({ frameId: this.frameId }).then(response => {
-				return response.body.scopes.map(rs => new Scope(this.threadId, rs.name, rs.variablesReference, rs.expensive));
+				return response.body.scopes.map(rs => new Scope(this.threadId, rs.name, rs.variablesReference, rs.expensive, rs.totalCount));
 			}, err => []);
 		}
 

src/vs/workbench/parts/debug/electron-browser/debugService.ts

@@ -623,7 +623,8 @@ export class DebugService implements debug.IDebugService {
 				pathFormat: 'path',
 				linesStartAt1: true,
 				columnsStartAt1: true,
-				supportsVariableType: true // #8858
+				supportsVariableType: true, // #8858
+				supportsVariablePaging: false // #9537
 			}).then((result: DebugProtocol.InitializeResponse) => {
 				if (!this.session) {
 					return TPromise.wrapError(new Error(nls.localize('debugAdapterCrash', "Debug adapter process has terminated unexpectedly")));

src/vs/workbench/parts/debug/test/node/debugModel.test.ts

@@ -352,11 +352,11 @@ suite('Debug - Model', () => {
 		assert.equal(debugmodel.getFullExpressionName(new debugmodel.Expression(null, false), type), null);
 		assert.equal(debugmodel.getFullExpressionName(new debugmodel.Expression('son', false), type), 'son');
 
-		const scope = new debugmodel.Scope(1, 'myscope', 1, false);
-		const son = new debugmodel.Variable(new debugmodel.Variable(new debugmodel.Variable(scope, 0, 'grandfather', '75'), 0, 'father', '45'), 0, 'son', '20');
+		const scope = new debugmodel.Scope(1, 'myscope', 1, false, 1);
+		const son = new debugmodel.Variable(new debugmodel.Variable(new debugmodel.Variable(scope, 0, 'grandfather', '75', 1), 0, 'father', '45', 1), 0, 'son', '20', 1);
 		assert.equal(debugmodel.getFullExpressionName(son, type), 'grandfather.father.son');
 
-		const grandson = new debugmodel.Variable(son, 0, '/weird_name', '1');
+		const grandson = new debugmodel.Variable(son, 0, '/weird_name', '1', 0);
 		assert.equal(debugmodel.getFullExpressionName(grandson, type), 'grandfather.father.son[\'/weird_name\']');
 	});
 });