Merge branch 'joh/editors'

2026-04-25 19:18:59 +01:00 · 2017-03-06 12:40:47 +01:00
parent 1645d0d150
commit 1239cebb70
22 changed files with 1310 additions and 997 deletions
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -13,6 +13,7 @@ import * as errors from 'vs/base/common/errors';
 import product from 'vs/platform/node/product';
 import pkg from 'vs/platform/node/package';
 import { ExtHostFileSystemEventService } from 'vs/workbench/api/node/extHostFileSystemEventService';
+import { ExtHostDocumentsAndEditors } from 'vs/workbench/api/node/extHostDocumentsAndEditors';
 import { ExtHostDocuments } from 'vs/workbench/api/node/extHostDocuments';
 import { ExtHostDocumentSaveParticipant } from 'vs/workbench/api/node/extHostDocumentSaveParticipant';
 import { ExtHostConfiguration } from 'vs/workbench/api/node/extHostConfiguration';
@@ -28,7 +29,7 @@ import { ExtHostCommands } from 'vs/workbench/api/node/extHostCommands';
 import { ExtHostOutputService } from 'vs/workbench/api/node/extHostOutputService';
 import { ExtHostTerminalService } from 'vs/workbench/api/node/extHostTerminalService';
 import { ExtHostMessageService } from 'vs/workbench/api/node/extHostMessageService';
-import { ExtHostEditors } from 'vs/workbench/api/node/extHostEditors';
+import { ExtHostEditors } from 'vs/workbench/api/node/extHostTextEditors';
 import { ExtHostLanguages } from 'vs/workbench/api/node/extHostLanguages';
 import { ExtHostLanguageFeatures } from 'vs/workbench/api/node/extHostLanguageFeatures';
 import { ExtHostApiCommands } from 'vs/workbench/api/node/extHostApiCommands';
@@ -97,9 +98,10 @@ export function createApiFactory(initData: IInitData, threadService: IThreadServ
 	// Addressable instances
 	const col = new InstanceCollection();
 	const extHostHeapService = col.define(ExtHostContext.ExtHostHeapService).set<ExtHostHeapService>(new ExtHostHeapService());
-	const extHostDocuments = col.define(ExtHostContext.ExtHostDocuments).set<ExtHostDocuments>(new ExtHostDocuments(threadService));
+	const extHostDocumentsAndEditors = col.define(ExtHostContext.ExtHostDocumentsAndEditors).set<ExtHostDocumentsAndEditors>(new ExtHostDocumentsAndEditors(threadService));
+	const extHostDocuments = col.define(ExtHostContext.ExtHostDocuments).set<ExtHostDocuments>(new ExtHostDocuments(threadService, extHostDocumentsAndEditors));
 	const extHostDocumentSaveParticipant = col.define(ExtHostContext.ExtHostDocumentSaveParticipant).set<ExtHostDocumentSaveParticipant>(new ExtHostDocumentSaveParticipant(extHostDocuments, threadService.get(MainContext.MainThreadWorkspace)));
-	const extHostEditors = col.define(ExtHostContext.ExtHostEditors).set<ExtHostEditors>(new ExtHostEditors(threadService, extHostDocuments));
+	const extHostEditors = col.define(ExtHostContext.ExtHostEditors).set<ExtHostEditors>(new ExtHostEditors(threadService, extHostDocumentsAndEditors));
 	const extHostCommands = col.define(ExtHostContext.ExtHostCommands).set<ExtHostCommands>(new ExtHostCommands(threadService, extHostEditors, extHostHeapService));
 	const extHostExplorers = col.define(ExtHostContext.ExtHostExplorers).set<ExtHostTreeExplorers>(new ExtHostTreeExplorers(threadService, extHostCommands));
 	const extHostConfiguration = col.define(ExtHostContext.ExtHostConfiguration).set<ExtHostConfiguration>(new ExtHostConfiguration(threadService.get(MainContext.MainThreadConfiguration), initData.configuration));
--- a/src/vs/workbench/api/node/extHost.contribution.ts
+++ b/src/vs/workbench/api/node/extHost.contribution.ts
@@ -36,6 +36,7 @@ import { MainThreadFileSystemEventService } from './mainThreadFileSystemEventSer
 import { MainThreadSCM } from './mainThreadSCM';

 // --- other interested parties
+import { MainThreadDocumentsAndEditors } from './mainThreadDocumentsAndEditors';
 import { JSONValidationExtensionPoint } from 'vs/platform/jsonschemas/common/jsonValidationExtensionPoint';
 import { LanguageConfigurationFileHandler } from 'vs/editor/node/languageConfigurationExtensionPoint';
 import { SaveParticipant } from './mainThreadSaveParticipant';
@@ -62,13 +63,15 @@ export class ExtHostContribution implements IWorkbenchContribution {
 			return this.instantiationService.createInstance(ctor);
 		};

+		const documentsAndEditors = this.instantiationService.createInstance(MainThreadDocumentsAndEditors);
+
 		// Addressable instances
 		const col = new InstanceCollection();
 		col.define(MainContext.MainThreadCommands).set(create(MainThreadCommands));
 		col.define(MainContext.MainThreadConfiguration).set(create(MainThreadConfiguration));
 		col.define(MainContext.MainThreadDiagnostics).set(create(MainThreadDiagnostics));
-		col.define(MainContext.MainThreadDocuments).set(create(MainThreadDocuments));
-		col.define(MainContext.MainThreadEditors).set(create(MainThreadEditors));
+		col.define(MainContext.MainThreadDocuments).set(this.instantiationService.createInstance(MainThreadDocuments, documentsAndEditors));
+		col.define(MainContext.MainThreadEditors).set(this.instantiationService.createInstance(MainThreadEditors, documentsAndEditors));
 		col.define(MainContext.MainThreadErrors).set(create(MainThreadErrors));
 		col.define(MainContext.MainThreadExplorers).set(create(MainThreadTreeExplorers));
 		col.define(MainContext.MainThreadLanguageFeatures).set(create(MainThreadLanguageFeatures));
--- a/src/vs/workbench/api/node/extHost.protocol.ts
+++ b/src/vs/workbench/api/node/extHost.protocol.ts
@@ -35,7 +35,7 @@ import { IWorkspaceConfigurationValues } from 'vs/workbench/services/configurati
 import { IPickOpenEntry, IPickOptions } from 'vs/platform/quickOpen/common/quickOpen';
 import { SaveReason } from 'vs/workbench/services/textfile/common/textfiles';
 import { IWorkspaceSymbol } from 'vs/workbench/parts/search/common/search';
-import { IApplyEditsOptions, IUndoStopOptions, TextEditorRevealType, ITextEditorConfigurationUpdate, IResolvedTextEditorConfiguration, ISelectionChangeEvent } from './mainThreadEditorsTracker';
+import { IApplyEditsOptions, IUndoStopOptions, TextEditorRevealType, ITextEditorConfigurationUpdate, IResolvedTextEditorConfiguration, ISelectionChangeEvent } from './mainThreadEditor';

 import { InternalTreeExplorerNodeContent } from 'vs/workbench/parts/explorers/common/treeExplorerViewModel';

@@ -290,12 +290,10 @@ export interface IModelAddedData {
 }
 export abstract class ExtHostDocumentsShape {
 	$provideTextDocumentContent(handle: number, uri: URI): TPromise<string> { throw ni(); }
-	$acceptModelAdd(initData: IModelAddedData): void { throw ni(); }
 	$acceptModelModeChanged(strURL: string, oldModeId: string, newModeId: string): void { throw ni(); }
 	$acceptModelSaved(strURL: string): void { throw ni(); }
 	$acceptModelDirty(strURL: string): void { throw ni(); }
 	$acceptModelReverted(strURL: string): void { throw ni(); }
-	$acceptModelRemoved(strURL: string): void { throw ni(); }
 	$acceptModelChanged(strURL: string, events: editorCommon.IModelContentChangedEvent2[], isDirty: boolean): void { throw ni(); }
 }

@@ -314,14 +312,24 @@ export interface ITextEditorPositionData {
 	[id: string]: EditorPosition;
 }
 export abstract class ExtHostEditorsShape {
-	$acceptTextEditorAdd(data: ITextEditorAddData): void { throw ni(); }
 	$acceptOptionsChanged(id: string, opts: IResolvedTextEditorConfiguration): void { throw ni(); }
 	$acceptSelectionsChanged(id: string, event: ISelectionChangeEvent): void { throw ni(); }
-	$acceptActiveEditorAndVisibleEditors(id: string, visibleIds: string[]): void { throw ni(); }
 	$acceptEditorPositionData(data: ITextEditorPositionData): void { throw ni(); }
-	$acceptTextEditorRemove(id: string): void { throw ni(); }
 }

+export interface IDocumentsAndEditorsDelta {
+	removedDocuments?: string[];
+	addedDocuments?: IModelAddedData[];
+	removedEditors?: string[];
+	addedEditors?: ITextEditorAddData[];
+	newActiveEditor?: string;
+}
+
+export abstract class ExtHostDocumentsAndEditorsShape {
+	$acceptDocumentsAndEditorsDelta(delta: IDocumentsAndEditorsDelta): void { throw ni(); }
+}
+
+
 export abstract class ExtHostTreeExplorersShape {
 	$provideRootNode(providerId: string): TPromise<InternalTreeExplorerNodeContent> { throw ni(); };
 	$resolveChildren(providerId: string, node: InternalTreeExplorerNodeContent): TPromise<InternalTreeExplorerNodeContent[]> { throw ni(); }
@@ -432,6 +440,7 @@ export const ExtHostContext = {
 	ExtHostCommands: createExtId<ExtHostCommandsShape>('ExtHostCommands', ExtHostCommandsShape),
 	ExtHostConfiguration: createExtId<ExtHostConfigurationShape>('ExtHostConfiguration', ExtHostConfigurationShape),
 	ExtHostDiagnostics: createExtId<ExtHostDiagnosticsShape>('ExtHostDiagnostics', ExtHostDiagnosticsShape),
+	ExtHostDocumentsAndEditors: createExtId<ExtHostDocumentsAndEditorsShape>('ExtHostDocumentsAndEditors', ExtHostDocumentsAndEditorsShape),
 	ExtHostDocuments: createExtId<ExtHostDocumentsShape>('ExtHostDocuments', ExtHostDocumentsShape),
 	ExtHostDocumentSaveParticipant: createExtId<ExtHostDocumentSaveParticipantShape>('ExtHostDocumentSaveParticipant', ExtHostDocumentSaveParticipantShape),
 	ExtHostEditors: createExtId<ExtHostEditorsShape>('ExtHostEditors', ExtHostEditorsShape),
--- a/src/vs/workbench/api/node/extHostCommands.ts
+++ b/src/vs/workbench/api/node/extHostCommands.ts
@@ -8,7 +8,7 @@ import { IThreadService } from 'vs/workbench/services/thread/common/threadServic
 import { validateConstraint } from 'vs/base/common/types';
 import { ICommandHandlerDescription } from 'vs/platform/commands/common/commands';
 import { TPromise } from 'vs/base/common/winjs.base';
-import { ExtHostEditors } from 'vs/workbench/api/node/extHostEditors';
+import { ExtHostEditors } from 'vs/workbench/api/node/extHostTextEditors';
 import * as extHostTypes from 'vs/workbench/api/node/extHostTypes';
 import * as extHostTypeConverter from 'vs/workbench/api/node/extHostTypeConverters';
 import { cloneAndChange } from 'vs/base/common/objects';
@@ -102,7 +102,7 @@ export class ExtHostCommands extends ExtHostCommandsShape {
 			return TPromise.wrapError<T>(`Contributed command '${id}' does not exist.`);
 		}

-		let {callback, thisArg, description} = command;
+		let { callback, thisArg, description } = command;

 		if (description) {
 			for (let i = 0; i < description.args.length; i++) {
@@ -140,7 +140,7 @@ export class ExtHostCommands extends ExtHostCommandsShape {
 	$getContributedCommandHandlerDescriptions(): TPromise<{ [id: string]: string | ICommandHandlerDescription }> {
 		const result: { [id: string]: string | ICommandHandlerDescription } = Object.create(null);
 		this._commands.forEach((command, id) => {
-			let {description} = command;
+			let { description } = command;
 			if (description) {
 				result[id] = description;
 			}
--- a/src/vs/workbench/api/node/extHostDocumentData.ts
+++ b/src/vs/workbench/api/node/extHostDocumentData.ts
@@ -0,0 +1,244 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { regExpLeadsToEndlessLoop } from 'vs/base/common/strings';
+import { MirrorModel2 } from 'vs/editor/common/model/mirrorModel2';
+import URI from 'vs/base/common/uri';
+import { Range, Position } from 'vs/workbench/api/node/extHostTypes';
+import * as vscode from 'vscode';
+import { getWordAtText, ensureValidWordDefinition } from 'vs/editor/common/model/wordHelper';
+import { MainThreadDocumentsShape } from './extHost.protocol';
+import { ITextSource } from 'vs/editor/common/model/textSource';
+
+const _modeId2WordDefinition = new Map<string, RegExp>();
+export function setWordDefinitionFor(modeId: string, wordDefinition: RegExp): void {
+	_modeId2WordDefinition.set(modeId, wordDefinition);
+}
+export function getWordDefinitionFor(modeId: string): RegExp {
+	return _modeId2WordDefinition.get(modeId);
+}
+
+export class ExtHostDocumentData extends MirrorModel2 {
+
+	private _proxy: MainThreadDocumentsShape;
+	private _languageId: string;
+	private _isDirty: boolean;
+	private _textLines: vscode.TextLine[];
+	private _document: vscode.TextDocument;
+
+	constructor(proxy: MainThreadDocumentsShape, uri: URI, lines: string[], eol: string,
+		languageId: string, versionId: number, isDirty: boolean) {
+
+		super(uri, lines, eol, versionId);
+		this._proxy = proxy;
+		this._languageId = languageId;
+		this._isDirty = isDirty;
+		this._textLines = [];
+	}
+
+	dispose(): void {
+		this._textLines.length = 0;
+		this._isDirty = false;
+		super.dispose();
+	}
+
+	equalLines({ lines }: ITextSource): boolean {
+		const len = lines.length;
+		if (len !== this._lines.length) {
+			return false;
+		}
+		for (let i = 0; i < len; i++) {
+			if (lines[i] !== this._lines[i]) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	get document(): vscode.TextDocument {
+		if (!this._document) {
+			const data = this;
+			this._document = {
+				get uri() { return data._uri; },
+				get fileName() { return data._uri.fsPath; },
+				get isUntitled() { return data._uri.scheme !== 'file'; },
+				get languageId() { return data._languageId; },
+				get version() { return data._versionId; },
+				get isDirty() { return data._isDirty; },
+				save() { return data._proxy.$trySaveDocument(data._uri); },
+				getText(range?) { return range ? data._getTextInRange(range) : data.getText(); },
+				get lineCount() { return data._lines.length; },
+				lineAt(lineOrPos) { return data.lineAt(lineOrPos); },
+				offsetAt(pos) { return data.offsetAt(pos); },
+				positionAt(offset) { return data.positionAt(offset); },
+				validateRange(ran) { return data.validateRange(ran); },
+				validatePosition(pos) { return data.validatePosition(pos); },
+				getWordRangeAtPosition(pos, regexp?) { return data.getWordRangeAtPosition(pos, regexp); }
+			};
+		}
+		return this._document;
+	}
+
+	_acceptLanguageId(newLanguageId: string): void {
+		this._languageId = newLanguageId;
+	}
+
+	_acceptIsDirty(isDirty: boolean): void {
+		this._isDirty = isDirty;
+	}
+
+	private _getTextInRange(_range: vscode.Range): string {
+		let range = this.validateRange(_range);
+
+		if (range.isEmpty) {
+			return '';
+		}
+
+		if (range.isSingleLine) {
+			return this._lines[range.start.line].substring(range.start.character, range.end.character);
+		}
+
+		let lineEnding = this._eol,
+			startLineIndex = range.start.line,
+			endLineIndex = range.end.line,
+			resultLines: string[] = [];
+
+		resultLines.push(this._lines[startLineIndex].substring(range.start.character));
+		for (let i = startLineIndex + 1; i < endLineIndex; i++) {
+			resultLines.push(this._lines[i]);
+		}
+		resultLines.push(this._lines[endLineIndex].substring(0, range.end.character));
+
+		return resultLines.join(lineEnding);
+	}
+
+	lineAt(lineOrPosition: number | vscode.Position): vscode.TextLine {
+
+		let line: number;
+		if (lineOrPosition instanceof Position) {
+			line = lineOrPosition.line;
+		} else if (typeof lineOrPosition === 'number') {
+			line = lineOrPosition;
+		}
+
+		if (line < 0 || line >= this._lines.length) {
+			throw new Error('Illegal value for `line`');
+		}
+
+		let result = this._textLines[line];
+		if (!result || result.lineNumber !== line || result.text !== this._lines[line]) {
+
+			const text = this._lines[line];
+			const firstNonWhitespaceCharacterIndex = /^(\s*)/.exec(text)[1].length;
+			const range = new Range(line, 0, line, text.length);
+			const rangeIncludingLineBreak = line < this._lines.length - 1
+				? new Range(line, 0, line + 1, 0)
+				: range;
+
+			result = Object.freeze({
+				lineNumber: line,
+				range,
+				rangeIncludingLineBreak,
+				text,
+				firstNonWhitespaceCharacterIndex, //TODO@api, rename to 'leadingWhitespaceLength'
+				isEmptyOrWhitespace: firstNonWhitespaceCharacterIndex === text.length
+			});
+
+			this._textLines[line] = result;
+		}
+
+		return result;
+	}
+
+	offsetAt(position: vscode.Position): number {
+		position = this.validatePosition(position);
+		this._ensureLineStarts();
+		return this._lineStarts.getAccumulatedValue(position.line - 1) + position.character;
+	}
+
+	positionAt(offset: number): vscode.Position {
+		offset = Math.floor(offset);
+		offset = Math.max(0, offset);
+
+		this._ensureLineStarts();
+		let out = this._lineStarts.getIndexOf(offset);
+
+		let lineLength = this._lines[out.index].length;
+
+		// Ensure we return a valid position
+		return new Position(out.index, Math.min(out.remainder, lineLength));
+	}
+
+	// ---- range math
+
+	validateRange(range: vscode.Range): vscode.Range {
+		if (!(range instanceof Range)) {
+			throw new Error('Invalid argument');
+		}
+
+		let start = this.validatePosition(range.start);
+		let end = this.validatePosition(range.end);
+
+		if (start === range.start && end === range.end) {
+			return range;
+		}
+		return new Range(start.line, start.character, end.line, end.character);
+	}
+
+	validatePosition(position: vscode.Position): vscode.Position {
+		if (!(position instanceof Position)) {
+			throw new Error('Invalid argument');
+		}
+
+		let { line, character } = position;
+		let hasChanged = false;
+
+		if (line < 0) {
+			line = 0;
+			character = 0;
+			hasChanged = true;
+		}
+		else if (line >= this._lines.length) {
+			line = this._lines.length - 1;
+			character = this._lines[line].length;
+			hasChanged = true;
+		}
+		else {
+			let maxCharacter = this._lines[line].length;
+			if (character < 0) {
+				character = 0;
+				hasChanged = true;
+			}
+			else if (character > maxCharacter) {
+				character = maxCharacter;
+				hasChanged = true;
+			}
+		}
+
+		if (!hasChanged) {
+			return position;
+		}
+		return new Position(line, character);
+	}
+
+	getWordRangeAtPosition(_position: vscode.Position, regexp?: RegExp): vscode.Range {
+		let position = this.validatePosition(_position);
+		if (!regexp || regExpLeadsToEndlessLoop(regexp)) {
+			regexp = getWordDefinitionFor(this._languageId);
+		}
+		let wordAtText = getWordAtText(
+			position.character + 1,
+			ensureValidWordDefinition(regexp),
+			this._lines[position.line],
+			0
+		);
+
+		if (wordAtText) {
+			return new Range(position.line, wordAtText.startColumn - 1, position.line, wordAtText.endColumn - 1);
+		}
+		return undefined;
+	}
+}
--- a/src/vs/workbench/api/node/extHostDocuments.ts
+++ b/src/vs/workbench/api/node/extHostDocuments.ts
@@ -5,82 +5,74 @@
 'use strict';

 import { onUnexpectedError } from 'vs/base/common/errors';
-import { regExpLeadsToEndlessLoop } from 'vs/base/common/strings';
 import * as editorCommon from 'vs/editor/common/editorCommon';
-import { MirrorModel2 } from 'vs/editor/common/model/mirrorModel2';
 import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
 import Event, { Emitter } from 'vs/base/common/event';
 import URI from 'vs/base/common/uri';
-import { IDisposable } from 'vs/base/common/lifecycle';
-import { Range, Position, Disposable } from 'vs/workbench/api/node/extHostTypes';
+import { IDisposable, dispose } from 'vs/base/common/lifecycle';
+import { Disposable } from 'vs/workbench/api/node/extHostTypes';
 import * as TypeConverters from './extHostTypeConverters';
 import { TPromise } from 'vs/base/common/winjs.base';
 import * as vscode from 'vscode';
 import { asWinJsPromise } from 'vs/base/common/async';
-import { getWordAtText, ensureValidWordDefinition } from 'vs/editor/common/model/wordHelper';
-import { MainContext, MainThreadDocumentsShape, ExtHostDocumentsShape, IModelAddedData } from './extHost.protocol';
-import { ITextSource, TextSource } from 'vs/editor/common/model/textSource';
-
-const _modeId2WordDefinition = new Map<string, RegExp>();
-
-function setWordDefinitionFor(modeId: string, wordDefinition: RegExp): void {
-	_modeId2WordDefinition.set(modeId, wordDefinition);
-}
-
-function getWordDefinitionFor(modeId: string): RegExp {
-	return _modeId2WordDefinition.get(modeId);
-}
+import { TextSource } from 'vs/editor/common/model/textSource';
+import { MainContext, MainThreadDocumentsShape, ExtHostDocumentsShape } from './extHost.protocol';
+import { ExtHostDocumentData, setWordDefinitionFor } from './extHostDocumentData';
+import { ExtHostDocumentsAndEditors } from './extHostDocumentsAndEditors';

 export class ExtHostDocuments extends ExtHostDocumentsShape {

 	private static _handlePool: number = 0;

-	private _onDidAddDocumentEventEmitter: Emitter<vscode.TextDocument>;
-	public onDidAddDocument: Event<vscode.TextDocument>;
+	private _onDidAddDocument = new Emitter<vscode.TextDocument>();
+	private _onDidRemoveDocument = new Emitter<vscode.TextDocument>();
+	private _onDidChangeDocument = new Emitter<vscode.TextDocumentChangeEvent>();
+	private _onDidSaveDocument = new Emitter<vscode.TextDocument>();

-	private _onDidRemoveDocumentEventEmitter: Emitter<vscode.TextDocument>;
-	public onDidRemoveDocument: Event<vscode.TextDocument>;
+	readonly onDidAddDocument: Event<vscode.TextDocument> = this._onDidAddDocument.event;
+	readonly onDidRemoveDocument: Event<vscode.TextDocument> = this._onDidRemoveDocument.event;
+	readonly onDidChangeDocument: Event<vscode.TextDocumentChangeEvent> = this._onDidChangeDocument.event;
+	readonly onDidSaveDocument: Event<vscode.TextDocument> = this._onDidSaveDocument.event;

-	private _onDidChangeDocumentEventEmitter: Emitter<vscode.TextDocumentChangeEvent>;
-	public onDidChangeDocument: Event<vscode.TextDocumentChangeEvent>;
-
-	private _onDidSaveDocumentEventEmitter: Emitter<vscode.TextDocument>;
-	public onDidSaveDocument: Event<vscode.TextDocument>;
-
-	private _documentData = new Map<string, ExtHostDocumentData>();
+	private _toDispose: IDisposable[];
+	private _proxy: MainThreadDocumentsShape;
+	private _documentsAndEditors: ExtHostDocumentsAndEditors;
 	private _documentLoader = new Map<string, TPromise<ExtHostDocumentData>>();
 	private _documentContentProviders = new Map<number, vscode.TextDocumentContentProvider>();

-	private _proxy: MainThreadDocumentsShape;

-	constructor(threadService: IThreadService) {
+	constructor(threadService: IThreadService, documentsAndEditors: ExtHostDocumentsAndEditors) {
 		super();
 		this._proxy = threadService.get(MainContext.MainThreadDocuments);
+		this._documentsAndEditors = documentsAndEditors;

-		this._onDidAddDocumentEventEmitter = new Emitter<vscode.TextDocument>();
-		this.onDidAddDocument = this._onDidAddDocumentEventEmitter.event;
+		this._toDispose = [
+			this._documentsAndEditors.onDidRemoveDocuments(documents => {
+				for (const data of documents) {
+					this._onDidRemoveDocument.fire(data.document);
+				}
+			}),
+			this._documentsAndEditors.onDidAddDocuments(documents => {
+				for (const data of documents) {
+					this._onDidAddDocument.fire(data.document);
+				}
+			})
+		];
+	}

-		this._onDidRemoveDocumentEventEmitter = new Emitter<vscode.TextDocument>();
-		this.onDidRemoveDocument = this._onDidRemoveDocumentEventEmitter.event;
-
-		this._onDidChangeDocumentEventEmitter = new Emitter<vscode.TextDocumentChangeEvent>();
-		this.onDidChangeDocument = this._onDidChangeDocumentEventEmitter.event;
-
-		this._onDidSaveDocumentEventEmitter = new Emitter<vscode.TextDocument>();
-		this.onDidSaveDocument = this._onDidSaveDocumentEventEmitter.event;
+	public dispose(): void {
+		dispose(this._toDispose);
 	}

 	public getAllDocumentData(): ExtHostDocumentData[] {
-		const result: ExtHostDocumentData[] = [];
-		this._documentData.forEach(data => result.push(data));
-		return result;
+		return this._documentsAndEditors.allDocuments();
 	}

 	public getDocumentData(resource: vscode.Uri): ExtHostDocumentData {
 		if (!resource) {
 			return undefined;
 		}
-		const data = this._documentData.get(resource.toString());
+		const data = this._documentsAndEditors.getDocument(resource.toString());
 		if (data) {
 			return data;
 		}
@@ -89,7 +81,7 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {

 	public ensureDocumentData(uri: URI): TPromise<ExtHostDocumentData> {

-		let cached = this._documentData.get(uri.toString());
+		let cached = this._documentsAndEditors.getDocument(uri.toString());
 		if (cached) {
 			return TPromise.as(cached);
 		}
@@ -98,7 +90,7 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 		if (!promise) {
 			promise = this._proxy.$tryOpenDocument(uri).then(() => {
 				this._documentLoader.delete(uri.toString());
-				return this._documentData.get(uri.toString());
+				return this._documentsAndEditors.getDocument(uri.toString());
 			}, err => {
 				this._documentLoader.delete(uri.toString());
 				return TPromise.wrapError(err);
@@ -126,10 +118,10 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 		let subscription: IDisposable;
 		if (typeof provider.onDidChange === 'function') {
 			subscription = provider.onDidChange(uri => {
-				if (this._documentData.has(uri.toString())) {
+				if (this._documentsAndEditors.getDocument(uri.toString())) {
 					this.$provideTextDocumentContent(handle, <URI>uri).then(value => {

-						const document = this._documentData.get(uri.toString());
+						const document = this._documentsAndEditors.getDocument(uri.toString());
 						if (!document) {
 							// disposed in the meantime
 							return;
@@ -158,7 +150,7 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 		});
 	}

-	$provideTextDocumentContent(handle: number, uri: URI): TPromise<string> {
+	public $provideTextDocumentContent(handle: number, uri: URI): TPromise<string> {
 		const provider = this._documentContentProviders.get(handle);
 		if (!provider) {
 			return TPromise.wrapError<string>(`unsupported uri-scheme: ${uri.scheme}`);
@@ -166,57 +158,37 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 		return asWinJsPromise(token => provider.provideTextDocumentContent(uri, token));
 	}

-	public $acceptModelAdd(initData: IModelAddedData): void {
-		let data = new ExtHostDocumentData(this._proxy, initData.url, initData.lines, initData.EOL, initData.modeId, initData.versionId, initData.isDirty);
-		let key = data.document.uri.toString();
-		if (this._documentData.has(key)) {
-			throw new Error('Document `' + key + '` already exists.');
-		}
-		this._documentData.set(key, data);
-		this._onDidAddDocumentEventEmitter.fire(data.document);
-	}
-
 	public $acceptModelModeChanged(strURL: string, oldModeId: string, newModeId: string): void {
-		let data = this._documentData.get(strURL);
+		let data = this._documentsAndEditors.getDocument(strURL);

 		// Treat a mode change as a remove + add

-		this._onDidRemoveDocumentEventEmitter.fire(data.document);
+		this._onDidRemoveDocument.fire(data.document);
 		data._acceptLanguageId(newModeId);
-		this._onDidAddDocumentEventEmitter.fire(data.document);
+		this._onDidAddDocument.fire(data.document);
 	}

 	public $acceptModelSaved(strURL: string): void {
-		let data = this._documentData.get(strURL);
+		let data = this._documentsAndEditors.getDocument(strURL);
 		data._acceptIsDirty(false);
-		this._onDidSaveDocumentEventEmitter.fire(data.document);
+		this._onDidSaveDocument.fire(data.document);
 	}

 	public $acceptModelDirty(strURL: string): void {
-		let document = this._documentData.get(strURL);
+		let document = this._documentsAndEditors.getDocument(strURL);
 		document._acceptIsDirty(true);
 	}

 	public $acceptModelReverted(strURL: string): void {
-		let document = this._documentData.get(strURL);
+		let document = this._documentsAndEditors.getDocument(strURL);
 		document._acceptIsDirty(false);
 	}

-	public $acceptModelRemoved(strURL: string): void {
-		if (!this._documentData.has(strURL)) {
-			throw new Error('Document `' + strURL + '` does not exist.');
-		}
-		let data = this._documentData.get(strURL);
-		this._documentData.delete(strURL);
-		this._onDidRemoveDocumentEventEmitter.fire(data.document);
-		data.dispose();
-	}
-
 	public $acceptModelChanged(strURL: string, events: editorCommon.IModelContentChangedEvent2[], isDirty: boolean): void {
-		let data = this._documentData.get(strURL);
+		let data = this._documentsAndEditors.getDocument(strURL);
 		data._acceptIsDirty(isDirty);
 		data.onEvents(events);
-		this._onDidChangeDocumentEventEmitter.fire({
+		this._onDidChangeDocument.fire({
 			document: data.document,
 			contentChanges: events.map((e) => {
 				return {
@@ -228,229 +200,7 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 		});
 	}

-	setWordDefinitionFor(modeId: string, wordDefinition: RegExp): void {
+	public setWordDefinitionFor(modeId: string, wordDefinition: RegExp): void {
 		setWordDefinitionFor(modeId, wordDefinition);
 	}
 }
-
-export class ExtHostDocumentData extends MirrorModel2 {
-
-	private _proxy: MainThreadDocumentsShape;
-	private _languageId: string;
-	private _isDirty: boolean;
-	private _textLines: vscode.TextLine[];
-	private _document: vscode.TextDocument;
-
-	constructor(proxy: MainThreadDocumentsShape, uri: URI, lines: string[], eol: string,
-		languageId: string, versionId: number, isDirty: boolean) {
-
-		super(uri, lines, eol, versionId);
-		this._proxy = proxy;
-		this._languageId = languageId;
-		this._isDirty = isDirty;
-		this._textLines = [];
-	}
-
-	dispose(): void {
-		this._textLines.length = 0;
-		this._isDirty = false;
-		super.dispose();
-	}
-
-	equalLines({lines}: ITextSource): boolean {
-		const len = lines.length;
-		if (len !== this._lines.length) {
-			return false;
-		}
-		for (let i = 0; i < len; i++) {
-			if (lines[i] !== this._lines[i]) {
-				return false;
-			}
-		}
-		return true;
-	}
-
-	get document(): vscode.TextDocument {
-		if (!this._document) {
-			const data = this;
-			this._document = {
-				get uri() { return data._uri; },
-				get fileName() { return data._uri.fsPath; },
-				get isUntitled() { return data._uri.scheme !== 'file'; },
-				get languageId() { return data._languageId; },
-				get version() { return data._versionId; },
-				get isDirty() { return data._isDirty; },
-				save() { return data._proxy.$trySaveDocument(data._uri); },
-				getText(range?) { return range ? data._getTextInRange(range) : data.getText(); },
-				get lineCount() { return data._lines.length; },
-				lineAt(lineOrPos) { return data.lineAt(lineOrPos); },
-				offsetAt(pos) { return data.offsetAt(pos); },
-				positionAt(offset) { return data.positionAt(offset); },
-				validateRange(ran) { return data.validateRange(ran); },
-				validatePosition(pos) { return data.validatePosition(pos); },
-				getWordRangeAtPosition(pos, regexp?) { return data.getWordRangeAtPosition(pos, regexp); }
-			};
-		}
-		return this._document;
-	}
-
-	_acceptLanguageId(newLanguageId: string): void {
-		this._languageId = newLanguageId;
-	}
-
-	_acceptIsDirty(isDirty: boolean): void {
-		this._isDirty = isDirty;
-	}
-
-	private _getTextInRange(_range: vscode.Range): string {
-		let range = this.validateRange(_range);
-
-		if (range.isEmpty) {
-			return '';
-		}
-
-		if (range.isSingleLine) {
-			return this._lines[range.start.line].substring(range.start.character, range.end.character);
-		}
-
-		let lineEnding = this._eol,
-			startLineIndex = range.start.line,
-			endLineIndex = range.end.line,
-			resultLines: string[] = [];
-
-		resultLines.push(this._lines[startLineIndex].substring(range.start.character));
-		for (let i = startLineIndex + 1; i < endLineIndex; i++) {
-			resultLines.push(this._lines[i]);
-		}
-		resultLines.push(this._lines[endLineIndex].substring(0, range.end.character));
-
-		return resultLines.join(lineEnding);
-	}
-
-	lineAt(lineOrPosition: number | vscode.Position): vscode.TextLine {
-
-		let line: number;
-		if (lineOrPosition instanceof Position) {
-			line = lineOrPosition.line;
-		} else if (typeof lineOrPosition === 'number') {
-			line = lineOrPosition;
-		}
-
-		if (line < 0 || line >= this._lines.length) {
-			throw new Error('Illegal value for `line`');
-		}
-
-		let result = this._textLines[line];
-		if (!result || result.lineNumber !== line || result.text !== this._lines[line]) {
-
-			const text = this._lines[line];
-			const firstNonWhitespaceCharacterIndex = /^(\s*)/.exec(text)[1].length;
-			const range = new Range(line, 0, line, text.length);
-			const rangeIncludingLineBreak = line < this._lines.length - 1
-				? new Range(line, 0, line + 1, 0)
-				: range;
-
-			result = Object.freeze({
-				lineNumber: line,
-				range,
-				rangeIncludingLineBreak,
-				text,
-				firstNonWhitespaceCharacterIndex, //TODO@api, rename to 'leadingWhitespaceLength'
-				isEmptyOrWhitespace: firstNonWhitespaceCharacterIndex === text.length
-			});
-
-			this._textLines[line] = result;
-		}
-
-		return result;
-	}
-
-	offsetAt(position: vscode.Position): number {
-		position = this.validatePosition(position);
-		this._ensureLineStarts();
-		return this._lineStarts.getAccumulatedValue(position.line - 1) + position.character;
-	}
-
-	positionAt(offset: number): vscode.Position {
-		offset = Math.floor(offset);
-		offset = Math.max(0, offset);
-
-		this._ensureLineStarts();
-		let out = this._lineStarts.getIndexOf(offset);
-
-		let lineLength = this._lines[out.index].length;
-
-		// Ensure we return a valid position
-		return new Position(out.index, Math.min(out.remainder, lineLength));
-	}
-
-	// ---- range math
-
-	validateRange(range: vscode.Range): vscode.Range {
-		if (!(range instanceof Range)) {
-			throw new Error('Invalid argument');
-		}
-
-		let start = this.validatePosition(range.start);
-		let end = this.validatePosition(range.end);
-
-		if (start === range.start && end === range.end) {
-			return range;
-		}
-		return new Range(start.line, start.character, end.line, end.character);
-	}
-
-	validatePosition(position: vscode.Position): vscode.Position {
-		if (!(position instanceof Position)) {
-			throw new Error('Invalid argument');
-		}
-
-		let {line, character} = position;
-		let hasChanged = false;
-
-		if (line < 0) {
-			line = 0;
-			character = 0;
-			hasChanged = true;
-		}
-		else if (line >= this._lines.length) {
-			line = this._lines.length - 1;
-			character = this._lines[line].length;
-			hasChanged = true;
-		}
-		else {
-			let maxCharacter = this._lines[line].length;
-			if (character < 0) {
-				character = 0;
-				hasChanged = true;
-			}
-			else if (character > maxCharacter) {
-				character = maxCharacter;
-				hasChanged = true;
-			}
-		}
-
-		if (!hasChanged) {
-			return position;
-		}
-		return new Position(line, character);
-	}
-
-	getWordRangeAtPosition(_position: vscode.Position, regexp?: RegExp): vscode.Range {
-		let position = this.validatePosition(_position);
-		if (!regexp || regExpLeadsToEndlessLoop(regexp)) {
-			regexp = getWordDefinitionFor(this._languageId);
-		}
-		let wordAtText = getWordAtText(
-			position.character + 1,
-			ensureValidWordDefinition(regexp),
-			this._lines[position.line],
-			0
-		);
-
-		if (wordAtText) {
-			return new Range(position.line, wordAtText.startColumn - 1, position.line, wordAtText.endColumn - 1);
-		}
-		return undefined;
-	}
-}
--- a/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts
+++ b/src/vs/workbench/api/node/extHostDocumentsAndEditors.ts
@@ -0,0 +1,148 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import Event, { Emitter } from 'vs/base/common/event';
+import { dispose } from 'vs/base/common/lifecycle';
+import { MainContext, ExtHostDocumentsAndEditorsShape, IDocumentsAndEditorsDelta } from './extHost.protocol';
+import { ExtHostDocumentData } from './extHostDocumentData';
+import { ExtHostTextEditor } from './extHostTextEditor';
+import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
+import * as assert from 'assert';
+import * as typeConverters from './extHostTypeConverters';
+
+export class ExtHostDocumentsAndEditors extends ExtHostDocumentsAndEditorsShape {
+
+	private _activeEditorId: string;
+	private readonly _editors = new Map<string, ExtHostTextEditor>();
+	private readonly _documents = new Map<string, ExtHostDocumentData>();
+
+	private readonly _onDidAddDocuments = new Emitter<ExtHostDocumentData[]>();
+	private readonly _onDidRemoveDocuments = new Emitter<ExtHostDocumentData[]>();
+	private readonly _onDidChangeVisibleTextEditors = new Emitter<ExtHostTextEditor[]>();
+	private readonly _onDidChangeActiveTextEditor = new Emitter<ExtHostTextEditor>();
+
+	readonly onDidAddDocuments: Event<ExtHostDocumentData[]> = this._onDidAddDocuments.event;
+	readonly onDidRemoveDocuments: Event<ExtHostDocumentData[]> = this._onDidRemoveDocuments.event;
+	readonly onDidChangeVisibleTextEditors: Event<ExtHostTextEditor[]> = this._onDidChangeVisibleTextEditors.event;
+	readonly onDidChangeActiveTextEditor: Event<ExtHostTextEditor> = this._onDidChangeActiveTextEditor.event;
+
+	constructor(
+		@IThreadService private _threadService: IThreadService
+	) {
+		super();
+	}
+
+	$acceptDocumentsAndEditorsDelta(delta: IDocumentsAndEditorsDelta): void {
+
+		const removedDocuments: ExtHostDocumentData[] = [];
+		const addedDocuments: ExtHostDocumentData[] = [];
+		const removedEditors: ExtHostTextEditor[] = [];
+
+		if (delta.removedDocuments) {
+			for (const id of delta.removedDocuments) {
+				const data = this._documents.get(id);
+				this._documents.delete(id);
+				removedDocuments.push(data);
+			}
+		}
+
+		if (delta.addedDocuments) {
+			for (const data of delta.addedDocuments) {
+				assert.ok(!this._documents.has(data.url.toString()), `document '${data.url} already exists!'`);
+
+				const documentData = new ExtHostDocumentData(
+					this._threadService.get(MainContext.MainThreadDocuments),
+					data.url,
+					data.lines,
+					data.EOL,
+					data.modeId,
+					data.versionId,
+					data.isDirty
+				);
+				this._documents.set(data.url.toString(), documentData);
+				addedDocuments.push(documentData);
+			}
+		}
+
+		if (delta.removedEditors) {
+			for (const id of delta.removedEditors) {
+				const editor = this._editors.get(id);
+				this._editors.delete(id);
+				removedEditors.push(editor);
+			}
+		}
+
+		if (delta.addedEditors) {
+			for (const data of delta.addedEditors) {
+				assert.ok(this._documents.has(data.document.toString()), `document '${data.document}' does not exist`);
+				assert.ok(!this._editors.has(data.id), `editor '${data.id}' already exists!`);
+
+				const documentData = this._documents.get(data.document.toString());
+				const editor = new ExtHostTextEditor(
+					this._threadService.get(MainContext.MainThreadEditors),
+					data.id,
+					documentData,
+					data.selections.map(typeConverters.toSelection),
+					data.options,
+					typeConverters.toViewColumn(data.editorPosition)
+				);
+				this._editors.set(data.id, editor);
+			}
+		}
+
+		if (delta.newActiveEditor !== undefined) {
+			assert.ok(delta.newActiveEditor === null || this._editors.has(delta.newActiveEditor), `active editor '${delta.newActiveEditor}' does not exist`);
+			this._activeEditorId = delta.newActiveEditor;
+		}
+
+		// now that the internal state is complete, fire events
+		if (delta.removedDocuments) {
+			this._onDidRemoveDocuments.fire(removedDocuments);
+		}
+		if (delta.addedDocuments) {
+			this._onDidAddDocuments.fire(addedDocuments);
+		}
+
+		if (delta.removedEditors || delta.addedEditors) {
+			this._onDidChangeVisibleTextEditors.fire(this.allEditors());
+		}
+		if (delta.newActiveEditor) {
+			this._onDidChangeActiveTextEditor.fire(this.activeEditor());
+		}
+
+		// now that the events are out, dispose removed documents and editors
+		dispose(removedDocuments);
+		dispose(removedEditors);
+	}
+
+	getDocument(strUrl: string): ExtHostDocumentData {
+		return this._documents.get(strUrl);
+	}
+
+	allDocuments(): ExtHostDocumentData[] {
+		const result: ExtHostDocumentData[] = [];
+		this._documents.forEach(data => result.push(data));
+		return result;
+	}
+
+	getEditor(id: string): ExtHostTextEditor {
+		return this._editors.get(id);
+	}
+
+	activeEditor(): ExtHostTextEditor | undefined {
+		if (!this._activeEditorId) {
+			return undefined;
+		} else {
+			return this._editors.get(this._activeEditorId);
+		}
+	}
+
+	allEditors(): ExtHostTextEditor[] {
+		const result: ExtHostTextEditor[] = [];
+		this._editors.forEach(data => result.push(data));
+		return result;
+	}
+}
--- a/src/vs/workbench/api/node/extHostTextEditor.ts
+++ b/src/vs/workbench/api/node/extHostTextEditor.ts
@@ -4,174 +4,19 @@
 *--------------------------------------------------------------------------------------------*/
 'use strict';

-import URI from 'vs/base/common/uri';
+
 import { readonly, illegalArgument } from 'vs/base/common/errors';
-import { equals as arrayEquals } from 'vs/base/common/arrays';
 import { IdGenerator } from 'vs/base/common/idGenerator';
-import Event, { Emitter } from 'vs/base/common/event';
 import { TPromise } from 'vs/base/common/winjs.base';
-import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
-import { ExtHostDocuments, ExtHostDocumentData } from 'vs/workbench/api/node/extHostDocuments';
-import { Selection, Range, Position, EndOfLine, TextEditorRevealType, TextEditorSelectionChangeKind, TextEditorLineNumbersStyle, SnippetString } from './extHostTypes';
+import { ExtHostDocumentData } from 'vs/workbench/api/node/extHostDocumentData';
+import { Selection, Range, Position, EndOfLine, TextEditorRevealType, TextEditorLineNumbersStyle, SnippetString } from './extHostTypes';
 import { ISingleEditOperation, TextEditorCursorStyle, IRange } from 'vs/editor/common/editorCommon';
-import { IResolvedTextEditorConfiguration, ISelectionChangeEvent, ITextEditorConfigurationUpdate } from 'vs/workbench/api/node/mainThreadEditorsTracker';
+import { IResolvedTextEditorConfiguration, ITextEditorConfigurationUpdate } from 'vs/workbench/api/node/mainThreadEditor';
 import * as TypeConverters from './extHostTypeConverters';
-import { MainContext, MainThreadEditorsShape, ExtHostEditorsShape, ITextEditorAddData, ITextEditorPositionData } from './extHost.protocol';
+import { MainThreadEditorsShape } from './extHost.protocol';
 import * as vscode from 'vscode';

-export class ExtHostEditors extends ExtHostEditorsShape {
-
-	public onDidChangeTextEditorSelection: Event<vscode.TextEditorSelectionChangeEvent>;
-	private _onDidChangeTextEditorSelection: Emitter<vscode.TextEditorSelectionChangeEvent>;
-
-	public onDidChangeTextEditorOptions: Event<vscode.TextEditorOptionsChangeEvent>;
-	private _onDidChangeTextEditorOptions: Emitter<vscode.TextEditorOptionsChangeEvent>;
-
-	public onDidChangeTextEditorViewColumn: Event<vscode.TextEditorViewColumnChangeEvent>;
-	private _onDidChangeTextEditorViewColumn: Emitter<vscode.TextEditorViewColumnChangeEvent>;
-
-	private _editors: Map<string, ExtHostTextEditor>;
-	private _proxy: MainThreadEditorsShape;
-	private _onDidChangeActiveTextEditor: Emitter<vscode.TextEditor>;
-	private _onDidChangeVisibleTextEditors: Emitter<vscode.TextEditor[]>;
-	private _extHostDocuments: ExtHostDocuments;
-	private _activeEditorId: string;
-	private _visibleEditorIds: string[];
-
-	constructor(
-		threadService: IThreadService,
-		extHostDocuments: ExtHostDocuments
-	) {
-		super();
-		this._onDidChangeTextEditorSelection = new Emitter<vscode.TextEditorSelectionChangeEvent>();
-		this.onDidChangeTextEditorSelection = this._onDidChangeTextEditorSelection.event;
-
-		this._onDidChangeTextEditorOptions = new Emitter<vscode.TextEditorOptionsChangeEvent>();
-		this.onDidChangeTextEditorOptions = this._onDidChangeTextEditorOptions.event;
-
-		this._onDidChangeTextEditorViewColumn = new Emitter<vscode.TextEditorViewColumnChangeEvent>();
-		this.onDidChangeTextEditorViewColumn = this._onDidChangeTextEditorViewColumn.event;
-
-		this._extHostDocuments = extHostDocuments;
-		this._proxy = threadService.get(MainContext.MainThreadEditors);
-		this._onDidChangeActiveTextEditor = new Emitter<vscode.TextEditor>();
-		this._onDidChangeVisibleTextEditors = new Emitter<vscode.TextEditor[]>();
-		this._editors = new Map<string, ExtHostTextEditor>();
-
-		this._visibleEditorIds = [];
-	}
-
-	getActiveTextEditor(): vscode.TextEditor {
-		return this._editors.get(this._activeEditorId);
-	}
-
-	getVisibleTextEditors(): vscode.TextEditor[] {
-		return this._visibleEditorIds.map(id => this._editors.get(id));
-	}
-
-	get onDidChangeActiveTextEditor(): Event<vscode.TextEditor> {
-		return this._onDidChangeActiveTextEditor && this._onDidChangeActiveTextEditor.event;
-	}
-
-	get onDidChangeVisibleTextEditors(): Event<vscode.TextEditor[]> {
-		return this._onDidChangeVisibleTextEditors && this._onDidChangeVisibleTextEditors.event;
-	}
-
-	showTextDocument(document: vscode.TextDocument, column: vscode.ViewColumn, preserveFocus: boolean): TPromise<vscode.TextEditor> {
-		return this._proxy.$tryShowTextDocument(<URI>document.uri, TypeConverters.fromViewColumn(column), preserveFocus).then(id => {
-			let editor = this._editors.get(id);
-			if (editor) {
-				return editor;
-			} else {
-				throw new Error(`Failed to show text document ${document.uri.toString()}, should show in editor #${id}`);
-			}
-		});
-	}
-
-	createTextEditorDecorationType(options: vscode.DecorationRenderOptions): vscode.TextEditorDecorationType {
-		return new TextEditorDecorationType(this._proxy, options);
-	}
-
-	// --- called from main thread
-
-	$acceptTextEditorAdd(data: ITextEditorAddData): void {
-		let document = this._extHostDocuments.getDocumentData(data.document);
-		let newEditor = new ExtHostTextEditor(this._proxy, data.id, document, data.selections.map(TypeConverters.toSelection), data.options, TypeConverters.toViewColumn(data.editorPosition));
-		this._editors.set(data.id, newEditor);
-	}
-
-	$acceptOptionsChanged(id: string, opts: IResolvedTextEditorConfiguration): void {
-		let editor = this._editors.get(id);
-		editor._acceptOptions(opts);
-		this._onDidChangeTextEditorOptions.fire({
-			textEditor: editor,
-			options: opts
-		});
-	}
-
-	$acceptSelectionsChanged(id: string, event: ISelectionChangeEvent): void {
-		const kind = TextEditorSelectionChangeKind.fromValue(event.source);
-		const selections = event.selections.map(TypeConverters.toSelection);
-		const textEditor = this._editors.get(id);
-		textEditor._acceptSelections(selections);
-		this._onDidChangeTextEditorSelection.fire({
-			textEditor,
-			selections,
-			kind
-		});
-	}
-
-	$acceptActiveEditorAndVisibleEditors(id: string, visibleIds: string[]): void {
-		let visibleChanged = false;
-		let activeChanged = false;
-
-		if (!arrayEquals(this._visibleEditorIds, visibleIds)) {
-			this._visibleEditorIds = visibleIds;
-			visibleChanged = true;
-		}
-
-		if (this._activeEditorId !== id) {
-			this._activeEditorId = id;
-			activeChanged = true;
-		}
-
-		if (visibleChanged) {
-			this._onDidChangeVisibleTextEditors.fire(this.getVisibleTextEditors());
-		}
-		if (activeChanged) {
-			this._onDidChangeActiveTextEditor.fire(this.getActiveTextEditor());
-		}
-	}
-
-	$acceptEditorPositionData(data: ITextEditorPositionData): void {
-		for (let id in data) {
-			let textEditor = this._editors.get(id);
-			let viewColumn = TypeConverters.toViewColumn(data[id]);
-			if (textEditor.viewColumn !== viewColumn) {
-				textEditor._acceptViewColumn(viewColumn);
-				this._onDidChangeTextEditorViewColumn.fire({ textEditor, viewColumn });
-			}
-		}
-	}
-
-	$acceptTextEditorRemove(id: string): void {
-		// make sure the removed editor is not visible
-		let newVisibleEditors = this._visibleEditorIds.filter(visibleEditorId => visibleEditorId !== id);
-
-		if (this._activeEditorId === id) {
-			// removing the current active editor
-			this.$acceptActiveEditorAndVisibleEditors(undefined, newVisibleEditors);
-		} else {
-			this.$acceptActiveEditorAndVisibleEditors(this._activeEditorId, newVisibleEditors);
-		}
-
-		let editor = this._editors.get(id);
-		editor.dispose();
-		this._editors.delete(id);
-	}
-}
-
-class TextEditorDecorationType implements vscode.TextEditorDecorationType {
+export class TextEditorDecorationType implements vscode.TextEditorDecorationType {

 	private static _Keys = new IdGenerator('TextEditorDecorationType');

@@ -467,7 +312,7 @@ export class ExtHostTextEditorOptions implements vscode.TextEditorOptions {

 }

-class ExtHostTextEditor implements vscode.TextEditor {
+export class ExtHostTextEditor implements vscode.TextEditor {

 	private _proxy: MainThreadEditorsShape;
 	private _id: string;
@@ -630,7 +475,7 @@ class ExtHostTextEditor implements vscode.TextEditor {
 			ranges = this._selections.map(TypeConverters.fromRange);

 		} else if (where instanceof Position) {
-			const {lineNumber, column} = TypeConverters.fromPosition(where);
+			const { lineNumber, column } = TypeConverters.fromPosition(where);
 			ranges = [{ startLineNumber: lineNumber, startColumn: column, endLineNumber: lineNumber, endColumn: column }];

 		} else if (where instanceof Range) {
@@ -641,7 +486,7 @@ class ExtHostTextEditor implements vscode.TextEditor {
 				if (posOrRange instanceof Range) {
 					ranges.push(TypeConverters.fromRange(posOrRange));
 				} else {
-					const {lineNumber, column} = TypeConverters.fromPosition(posOrRange);
+					const { lineNumber, column } = TypeConverters.fromPosition(posOrRange);
 					ranges.push({ startLineNumber: lineNumber, startColumn: column, endLineNumber: lineNumber, endColumn: column });
 				}
 			}
--- a/src/vs/workbench/api/node/extHostTextEditors.ts
+++ b/src/vs/workbench/api/node/extHostTextEditors.ts
@@ -0,0 +1,105 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import URI from 'vs/base/common/uri';
+import Event, { Emitter } from 'vs/base/common/event';
+import { TPromise } from 'vs/base/common/winjs.base';
+import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
+import { TextEditorSelectionChangeKind } from './extHostTypes';
+import { IResolvedTextEditorConfiguration, ISelectionChangeEvent } from 'vs/workbench/api/node/mainThreadEditor';
+import * as TypeConverters from './extHostTypeConverters';
+import { TextEditorDecorationType } from './extHostTextEditor';
+import { ExtHostDocumentsAndEditors } from './extHostDocumentsAndEditors';
+import { MainContext, MainThreadEditorsShape, ExtHostEditorsShape, ITextEditorPositionData } from './extHost.protocol';
+import * as vscode from 'vscode';
+
+export class ExtHostEditors extends ExtHostEditorsShape {
+
+	private readonly _onDidChangeTextEditorSelection = new Emitter<vscode.TextEditorSelectionChangeEvent>();
+	private readonly _onDidChangeTextEditorOptions = new Emitter<vscode.TextEditorOptionsChangeEvent>();
+	private readonly _onDidChangeTextEditorViewColumn = new Emitter<vscode.TextEditorViewColumnChangeEvent>();
+	private readonly _onDidChangeActiveTextEditor = new Emitter<vscode.TextEditor>();
+	private readonly _onDidChangeVisibleTextEditors = new Emitter<vscode.TextEditor[]>();
+
+	readonly onDidChangeTextEditorSelection: Event<vscode.TextEditorSelectionChangeEvent> = this._onDidChangeTextEditorSelection.event;
+	readonly onDidChangeTextEditorOptions: Event<vscode.TextEditorOptionsChangeEvent> = this._onDidChangeTextEditorOptions.event;
+	readonly onDidChangeTextEditorViewColumn: Event<vscode.TextEditorViewColumnChangeEvent> = this._onDidChangeTextEditorViewColumn.event;
+	readonly onDidChangeActiveTextEditor: Event<vscode.TextEditor> = this._onDidChangeActiveTextEditor.event;
+	readonly onDidChangeVisibleTextEditors: Event<vscode.TextEditor[]> = this._onDidChangeVisibleTextEditors.event;
+
+
+	private _proxy: MainThreadEditorsShape;
+	private _extHostDocumentsAndEditors: ExtHostDocumentsAndEditors;
+
+	constructor(
+		threadService: IThreadService,
+		extHostDocumentsAndEditors: ExtHostDocumentsAndEditors,
+	) {
+		super();
+		this._proxy = threadService.get(MainContext.MainThreadEditors);
+		this._extHostDocumentsAndEditors = extHostDocumentsAndEditors;
+
+		this._extHostDocumentsAndEditors.onDidChangeVisibleTextEditors(e => this._onDidChangeVisibleTextEditors.fire(e));
+		this._extHostDocumentsAndEditors.onDidChangeActiveTextEditor(e => this._onDidChangeActiveTextEditor.fire(e));
+	}
+
+	getActiveTextEditor(): vscode.TextEditor {
+		return this._extHostDocumentsAndEditors.activeEditor();
+	}
+
+	getVisibleTextEditors(): vscode.TextEditor[] {
+		return this._extHostDocumentsAndEditors.allEditors();
+	}
+
+	showTextDocument(document: vscode.TextDocument, column: vscode.ViewColumn, preserveFocus: boolean): TPromise<vscode.TextEditor> {
+		return this._proxy.$tryShowTextDocument(<URI>document.uri, TypeConverters.fromViewColumn(column), preserveFocus).then(id => {
+			let editor = this._extHostDocumentsAndEditors.getEditor(id);
+			if (editor) {
+				return editor;
+			} else {
+				throw new Error(`Failed to show text document ${document.uri.toString()}, should show in editor #${id}`);
+			}
+		});
+	}
+
+	createTextEditorDecorationType(options: vscode.DecorationRenderOptions): vscode.TextEditorDecorationType {
+		return new TextEditorDecorationType(this._proxy, options);
+	}
+
+	// --- called from main thread
+
+	$acceptOptionsChanged(id: string, opts: IResolvedTextEditorConfiguration): void {
+		let editor = this._extHostDocumentsAndEditors.getEditor(id);
+		editor._acceptOptions(opts);
+		this._onDidChangeTextEditorOptions.fire({
+			textEditor: editor,
+			options: opts
+		});
+	}
+
+	$acceptSelectionsChanged(id: string, event: ISelectionChangeEvent): void {
+		const kind = TextEditorSelectionChangeKind.fromValue(event.source);
+		const selections = event.selections.map(TypeConverters.toSelection);
+		const textEditor = this._extHostDocumentsAndEditors.getEditor(id);
+		textEditor._acceptSelections(selections);
+		this._onDidChangeTextEditorSelection.fire({
+			textEditor,
+			selections,
+			kind
+		});
+	}
+
+	$acceptEditorPositionData(data: ITextEditorPositionData): void {
+		for (let id in data) {
+			let textEditor = this._extHostDocumentsAndEditors.getEditor(id);
+			let viewColumn = TypeConverters.toViewColumn(data[id]);
+			if (textEditor.viewColumn !== viewColumn) {
+				textEditor._acceptViewColumn(viewColumn);
+				this._onDidChangeTextEditorViewColumn.fire({ textEditor, viewColumn });
+			}
+		}
+	}
+}
--- a/src/vs/workbench/api/node/mainThreadDocuments.ts
+++ b/src/vs/workbench/api/node/mainThreadDocuments.ts
@@ -20,8 +20,10 @@ import { ExtHostContext, MainThreadDocumentsShape, ExtHostDocumentsShape } from
 import { ITextModelResolverService } from 'vs/editor/common/services/resolverService';
 import { ICodeEditorService } from 'vs/editor/common/services/codeEditorService';
 import { ITextSource } from 'vs/editor/common/model/textSource';
+import { MainThreadDocumentsAndEditors } from './mainThreadDocumentsAndEditors';

 export class MainThreadDocuments extends MainThreadDocumentsShape {
+
 	private _modelService: IModelService;
 	private _modeService: IModeService;
 	private _textModelResolverService: ITextModelResolverService;
@@ -36,6 +38,7 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 	private _resourceContentProvider: { [handle: number]: IDisposable };

 	constructor(
+		documentsAndEditors: MainThreadDocumentsAndEditors,
 		@IThreadService threadService: IThreadService,
 		@IModelService modelService: IModelService,
 		@IModeService modeService: IModeService,
@@ -57,8 +60,8 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 		this._modelIsSynced = {};

 		this._toDispose = [];
-		modelService.onModelAdded(this._onModelAdded, this, this._toDispose);
-		modelService.onModelRemoved(this._onModelRemoved, this, this._toDispose);
+		this._toDispose.push(documentsAndEditors.onDocumentAdd(models => models.forEach(this._onModelAdded, this)));
+		this._toDispose.push(documentsAndEditors.onDocumentRemove(urls => urls.forEach(this._onModelRemoved, this)));
 		modelService.onModelModeChanged(this._onModelModeChanged, this, this._toDispose);

 		this._toDispose.push(textFileService.models.onModelSaved(e => {
@@ -103,14 +106,6 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 		let modelUrl = model.uri;
 		this._modelIsSynced[modelUrl.toString()] = true;
 		this._modelToDisposeMap[modelUrl.toString()] = model.addBulkListener((events) => this._onModelEvents(modelUrl, events));
-		this._proxy.$acceptModelAdd({
-			url: model.uri,
-			versionId: model.getVersionId(),
-			lines: model.getLinesContent(),
-			EOL: model.getEOL(),
-			modeId: model.getLanguageIdentifier().language,
-			isDirty: this._textFileService.isDirty(modelUrl)
-		});
 	}

 	private _onModelModeChanged(event: { model: editorCommon.IModel; oldModeId: string; }): void {
@@ -122,15 +117,14 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 		this._proxy.$acceptModelModeChanged(model.uri.toString(), oldModeId, model.getLanguageIdentifier().language);
 	}

-	private _onModelRemoved(model: editorCommon.IModel): void {
-		let modelUrl = model.uri;
-		if (!this._modelIsSynced[modelUrl.toString()]) {
+	private _onModelRemoved(modelUrl: string): void {
+
+		if (!this._modelIsSynced[modelUrl]) {
 			return;
 		}
-		delete this._modelIsSynced[modelUrl.toString()];
-		this._modelToDisposeMap[modelUrl.toString()].dispose();
-		delete this._modelToDisposeMap[modelUrl.toString()];
-		this._proxy.$acceptModelRemoved(modelUrl.toString());
+		delete this._modelIsSynced[modelUrl];
+		this._modelToDisposeMap[modelUrl].dispose();
+		delete this._modelToDisposeMap[modelUrl];
 	}

 	private _onModelEvents(modelUrl: URI, events: EmitterEvent[]): void {
@@ -246,6 +240,7 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 		if (!model) {
 			return;
 		}
+
 		const raw: ITextSource = {
 			lines: value.lines,
 			length: value.length,
--- a/src/vs/workbench/api/node/mainThreadDocumentsAndEditors.ts
+++ b/src/vs/workbench/api/node/mainThreadDocumentsAndEditors.ts
@@ -0,0 +1,351 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import { IModelService } from 'vs/editor/common/services/modelService';
+import { IModel, ICommonCodeEditor, isCommonCodeEditor, isCommonDiffEditor } from 'vs/editor/common/editorCommon';
+import { compare } from 'vs/base/common/strings';
+import { delta } from 'vs/base/common/arrays';
+import { IDisposable, dispose } from 'vs/base/common/lifecycle';
+import { ICodeEditorService } from 'vs/editor/common/services/codeEditorService';
+import Event, { Emitter, any } from 'vs/base/common/event';
+import { ExtHostContext, ExtHostDocumentsAndEditorsShape, IModelAddedData, ITextEditorAddData, IDocumentsAndEditorsDelta } from './extHost.protocol';
+import { MainThreadTextEditor } from 'vs/workbench/api/node/mainThreadEditor';
+import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
+import { ITextFileService } from 'vs/workbench/services/textfile/common/textfiles';
+import { IWorkbenchEditorService } from 'vs/workbench/services/editor/common/editorService';
+import { Position as EditorPosition, IEditor } from 'vs/platform/editor/common/editor';
+
+namespace cmp {
+	export function compareModels(a: IModel, b: IModel): number {
+		return compare(a.uri.toString(), b.uri.toString());
+	}
+	export function compareEditors(a: EditorAndModel, b: EditorAndModel): number {
+		let ret = compare(a.editor.getId(), b.editor.getId());
+		if (ret === 0) {
+			ret = compare(a.document.uri.toString(), b.document.uri.toString());
+		}
+		return ret;
+	}
+}
+
+class EditorAndModel {
+
+	readonly id: string;
+
+	constructor(
+		readonly editor: ICommonCodeEditor,
+		readonly document: IModel,
+	) {
+		this.id = `${editor.getId()},${document.uri.toString()}`;
+	}
+}
+
+class DocumentAndEditorStateDelta {
+
+	readonly isEmpty: boolean;
+
+	constructor(
+		readonly removedDocuments: IModel[],
+		readonly addedDocuments: IModel[],
+		readonly removedEditors: EditorAndModel[],
+		readonly addedEditors: EditorAndModel[],
+		readonly oldActiveEditor: string,
+		readonly newActiveEditor: string,
+	) {
+		this.isEmpty = this.removedDocuments.length === 0
+			&& this.addedDocuments.length === 0
+			&& this.removedEditors.length === 0
+			&& this.addedEditors.length === 0
+			&& oldActiveEditor === newActiveEditor;
+	}
+
+	toString(): string {
+		let ret = 'DocumentAndEditorStateDelta\n';
+		ret += `\tRemoved Documents: [${this.removedDocuments.map(d => d.uri.toString(true)).join(', ')}]\n`;
+		ret += `\tAdded Documents: [${this.addedDocuments.map(d => d.uri.toString(true)).join(', ')}]\n`;
+		ret += `\tRemoved Editors: [${this.removedEditors.map(e => e.id).join(', ')}]\n`;
+		ret += `\tAdded Editors: [${this.addedEditors.map(e => e.id).join(', ')}]\n`;
+		ret += `\tNew Active Editor: ${this.newActiveEditor}\n`;
+		return ret;
+	}
+}
+
+class DocumentAndEditorState {
+
+	static compute(before: DocumentAndEditorState, after: DocumentAndEditorState): DocumentAndEditorStateDelta {
+		if (!before) {
+			return new DocumentAndEditorStateDelta([], after.documents, [], after.editors, undefined, after.activeEditor);
+		}
+		const documentDelta = delta(before.documents, after.documents, cmp.compareModels);
+		const editorDelta = delta(before.editors, after.editors, cmp.compareEditors);
+		const oldActiveEditor = before.activeEditor !== after.activeEditor ? before.activeEditor : undefined;
+		const newActiveEditor = before.activeEditor !== after.activeEditor ? after.activeEditor : undefined;
+
+		return new DocumentAndEditorStateDelta(
+			documentDelta.removed, documentDelta.added,
+			editorDelta.removed, editorDelta.added,
+			oldActiveEditor, newActiveEditor
+		);
+	}
+
+	constructor(
+		readonly documents: IModel[],
+		readonly editors: EditorAndModel[],
+		readonly activeEditor: string,
+	) {
+		this.documents = documents.sort(cmp.compareModels);
+		this.editors = editors.sort(cmp.compareEditors);
+	}
+}
+
+class MainThreadDocumentAndEditorStateComputer {
+
+	private _toDispose: IDisposable[] = [];
+	private _toDisposeOnEditorRemove = new Map<string, IDisposable>();
+	private _onDidChangeState = new Emitter<DocumentAndEditorStateDelta>();
+	private _currentState: DocumentAndEditorState;
+
+	readonly onDidChangeState: Event<DocumentAndEditorStateDelta> = this._onDidChangeState.event;
+
+	constructor(
+		@IModelService private _modelService: IModelService,
+		@ICodeEditorService private _codeEditorService: ICodeEditorService,
+		@IWorkbenchEditorService private _workbenchEditorService: IWorkbenchEditorService
+	) {
+		this._modelService.onModelAdded(this._updateState, this, this._toDispose);
+		this._modelService.onModelRemoved(this._updateState, this, this._toDispose);
+		this._codeEditorService.onCodeEditorAdd(this._onDidAddEditor, this, this._toDispose);
+		this._codeEditorService.onCodeEditorRemove(this._onDidRemoveEditor, this, this._toDispose);
+		// this._updateState();
+	}
+
+	dispose(): void {
+		this._toDispose = dispose(this._toDispose);
+	}
+
+	private _onDidAddEditor(e: ICommonCodeEditor): void {
+		const listener = any<any>(
+			e.onDidChangeModel,
+			e.onDidFocusEditor,
+			e.onDidBlurEditor
+		)(this._updateState, this);
+		this._toDisposeOnEditorRemove.set(e.getId(), listener);
+		this._updateState();
+	}
+
+	private _onDidRemoveEditor(e: ICommonCodeEditor): void {
+		const sub = this._toDisposeOnEditorRemove.get(e.getId());
+		if (sub) {
+			this._toDisposeOnEditorRemove.delete(e.getId());
+			sub.dispose();
+			this._updateState();
+		}
+	}
+
+	private _updateState(): void {
+
+		// models: ignore too large models
+		const models = this._modelService.getModels();
+		for (let i = 0; i < models.length; i++) {
+			if (models[i].isTooLargeForHavingARichMode()) {
+				models.splice(i, 1);
+				i--;
+			}
+		}
+
+		// editor: only take those that have a not too large model
+		const editors: EditorAndModel[] = [];
+		let activeEditor: string = null;
+
+		for (const editor of this._codeEditorService.listCodeEditors()) {
+			const model = editor.getModel();
+			if (model && !model.isTooLargeForHavingARichMode()
+				&& !model.isDisposed() // model disposed
+				&& Boolean(this._modelService.getModel(model.uri)) // model disposing, the flag didn't flip yet but the model service already removed it
+			) {
+				const apiEditor = new EditorAndModel(editor, model);
+				editors.push(apiEditor);
+				if (editor.isFocused()) {
+					activeEditor = apiEditor.id;
+				}
+			}
+		}
+
+		// active editor: if none of the previous editors had focus we try
+		// to match the action workbench editor with one of editor we have
+		// just computed
+		if (!activeEditor) {
+			const workbenchEditor = this._workbenchEditorService.getActiveEditor();
+			if (workbenchEditor) {
+				const workbenchEditorControl = workbenchEditor.getControl();
+				let candidate: ICommonCodeEditor;
+				if (isCommonCodeEditor(workbenchEditorControl)) {
+					candidate = workbenchEditorControl;
+				} else if (isCommonDiffEditor(workbenchEditorControl)) {
+					candidate = workbenchEditorControl.getModifiedEditor();
+				}
+				if (candidate) {
+					for (const { editor, id } of editors) {
+						if (candidate === editor) {
+							activeEditor = id;
+							break;
+						}
+					}
+				}
+			}
+		}
+
+		// compute new state and compare against old
+		const newState = new DocumentAndEditorState(models, editors, activeEditor);
+		const delta = DocumentAndEditorState.compute(this._currentState, newState);
+		if (!delta.isEmpty) {
+			this._currentState = newState;
+			this._onDidChangeState.fire(delta);
+		}
+	}
+}
+
+export class MainThreadDocumentsAndEditors {
+
+	private _toDispose: IDisposable[];
+	private _proxy: ExtHostDocumentsAndEditorsShape;
+	private _stateComputer: MainThreadDocumentAndEditorStateComputer;
+	private _editors = <{ [id: string]: MainThreadTextEditor }>Object.create(null);
+
+	private _onTextEditorAdd = new Emitter<MainThreadTextEditor[]>();
+	private _onTextEditorRemove = new Emitter<string[]>();
+	private _onDocumentAdd = new Emitter<IModel[]>();
+	private _onDocumentRemove = new Emitter<string[]>();
+
+	readonly onTextEditorAdd: Event<MainThreadTextEditor[]> = this._onTextEditorAdd.event;
+	readonly onTextEditorRemove: Event<string[]> = this._onTextEditorRemove.event;
+	readonly onDocumentAdd: Event<IModel[]> = this._onDocumentAdd.event;
+	readonly onDocumentRemove: Event<string[]> = this._onDocumentRemove.event;
+
+	constructor(
+		@IModelService private _modelService: IModelService,
+		@ITextFileService private _textFileService: ITextFileService,
+		@IWorkbenchEditorService private _workbenchEditorService: IWorkbenchEditorService,
+		@IThreadService threadService: IThreadService,
+		@ICodeEditorService codeEditorService: ICodeEditorService,
+	) {
+		this._proxy = threadService.get(ExtHostContext.ExtHostDocumentsAndEditors);
+		this._stateComputer = new MainThreadDocumentAndEditorStateComputer(_modelService, codeEditorService, _workbenchEditorService);
+		this._toDispose = [
+			this._stateComputer,
+			this._stateComputer.onDidChangeState(this._onDelta, this)
+		];
+	}
+
+	dispose(): void {
+		this._toDispose = dispose(this._toDispose);
+	}
+
+	private _onDelta(delta: DocumentAndEditorStateDelta): void {
+
+		let removedDocuments: string[];
+		let removedEditors: string[] = [];
+		let addedEditors: MainThreadTextEditor[] = [];
+
+		// removed models
+		removedDocuments = delta.removedDocuments.map(m => m.uri.toString());
+
+		// added editors
+		for (const apiEditor of delta.addedEditors) {
+			const mainThreadEditor = new MainThreadTextEditor(apiEditor.id, apiEditor.document,
+				apiEditor.editor, { onGainedFocus() { }, onLostFocus() { } }, this._modelService);
+
+			this._editors[apiEditor.id] = mainThreadEditor;
+			addedEditors.push(mainThreadEditor);
+		}
+
+		// removed editors
+		for (const { id } of delta.removedEditors) {
+			const mainThreadEditor = this._editors[id];
+			if (mainThreadEditor) {
+				mainThreadEditor.dispose();
+				delete this._editors[id];
+				removedEditors.push(id);
+			}
+		}
+
+		let extHostDelta: IDocumentsAndEditorsDelta = Object.create(null);
+		let empty = true;
+		if (delta.newActiveEditor !== undefined) {
+			empty = false;
+			extHostDelta.newActiveEditor = delta.newActiveEditor;
+		}
+		if (removedDocuments.length > 0) {
+			empty = false;
+			extHostDelta.removedDocuments = removedDocuments;
+		}
+		if (removedEditors.length > 0) {
+			empty = false;
+			extHostDelta.removedEditors = removedEditors;
+		}
+		if (delta.addedDocuments.length > 0) {
+			empty = false;
+			extHostDelta.addedDocuments = delta.addedDocuments.map(m => this._toModelAddData(m));
+		}
+		if (delta.addedEditors.length > 0) {
+			empty = false;
+			extHostDelta.addedEditors = addedEditors.map(e => this._toTextEditorAddData(e));
+		}
+
+		if (!empty) {
+			// first update ext host
+			this._proxy.$acceptDocumentsAndEditorsDelta(extHostDelta);
+			// second update dependent state listener
+			this._onDocumentRemove.fire(removedDocuments);
+			this._onDocumentAdd.fire(delta.addedDocuments);
+			this._onTextEditorRemove.fire(removedEditors);
+			this._onTextEditorAdd.fire(addedEditors);
+		}
+	}
+
+	private _toModelAddData(model: IModel): IModelAddedData {
+		return {
+			url: model.uri,
+			versionId: model.getVersionId(),
+			lines: model.getLinesContent(),
+			EOL: model.getEOL(),
+			modeId: model.getLanguageIdentifier().language,
+			isDirty: this._textFileService.isDirty(model.uri)
+		};
+	}
+
+	private _toTextEditorAddData(textEditor: MainThreadTextEditor): ITextEditorAddData {
+		return {
+			id: textEditor.getId(),
+			document: textEditor.getModel().uri,
+			options: textEditor.getConfiguration(),
+			selections: textEditor.getSelections(),
+			editorPosition: this._findEditorPosition(textEditor)
+		};
+	}
+
+	private _findEditorPosition(editor: MainThreadTextEditor): EditorPosition {
+		for (let workbenchEditor of this._workbenchEditorService.getVisibleEditors()) {
+			if (editor.matches(workbenchEditor)) {
+				return workbenchEditor.position;
+			}
+		}
+		return undefined;
+	}
+
+	findTextEditorIdFor(editor: IEditor): string {
+		for (let id in this._editors) {
+			if (this._editors[id].matches(editor)) {
+				return id;
+			}
+		}
+		return undefined;
+	}
+
+	getEditor(id: string): MainThreadTextEditor {
+		return this._editors[id];
+	}
+}
--- a/src/vs/workbench/api/node/mainThreadEditorsTracker.ts
+++ b/src/vs/workbench/api/node/mainThreadEditorsTracker.ts
@@ -7,11 +7,8 @@
 import EditorCommon = require('vs/editor/common/editorCommon');
 import Event, { Emitter } from 'vs/base/common/event';
 import { IEditor } from 'vs/platform/editor/common/editor';
-import { ICodeEditorService } from 'vs/editor/common/services/codeEditorService';
 import { IModelService } from 'vs/editor/common/services/modelService';
 import { IDisposable, dispose } from 'vs/base/common/lifecycle';
-import { RunOnceScheduler } from 'vs/base/common/async';
-import { IdGenerator } from 'vs/base/common/idGenerator';
 import { Range } from 'vs/editor/common/core/range';
 import { Selection } from 'vs/editor/common/core/selection';
 import { SnippetController } from 'vs/editor/contrib/snippet/common/snippetController';
@@ -131,6 +128,10 @@ export class MainThreadTextEditor {
 		return this._model;
 	}

+	public getCodeEditor(): EditorCommon.ICommonCodeEditor {
+		return this._codeEditor;
+	}
+
 	public hasCodeEditor(codeEditor: EditorCommon.ICommonCodeEditor): boolean {
 		return (this._codeEditor === codeEditor);
 	}
@@ -413,324 +414,3 @@ export class MainThreadTextEditor {
 		return true;
 	}
 }
-
-/**
- * Keeps track of what goes on in the main thread and maps models => text editors
- */
-export class MainThreadEditorsTracker {
-
-	private static _Ids = new IdGenerator('');
-
-	private _toDispose: IDisposable[];
-	private _codeEditorService: ICodeEditorService;
-	private _modelService: IModelService;
-	private _updateMapping: RunOnceScheduler;
-	private _editorModelChangeListeners: { [editorId: string]: IDisposable; };
-
-	private _model2TextEditors: {
-		[modelUri: string]: MainThreadTextEditor[];
-	};
-	private _focusedTextEditorId: string;
-	private _visibleTextEditorIds: string[];
-	private _onTextEditorAdd: Emitter<MainThreadTextEditor>;
-	private _onTextEditorRemove: Emitter<MainThreadTextEditor>;
-	private _onDidChangeFocusedTextEditor: Emitter<string>;
-	private _onDidUpdateTextEditors: Emitter<void>;
-
-	private _focusTracker: IFocusTracker;
-
-	constructor(
-		editorService: ICodeEditorService,
-		modelService: IModelService
-	) {
-		this._codeEditorService = editorService;
-		this._modelService = modelService;
-		this._toDispose = [];
-		this._focusedTextEditorId = null;
-		this._visibleTextEditorIds = [];
-		this._editorModelChangeListeners = Object.create(null);
-		this._model2TextEditors = Object.create(null);
-		this._onTextEditorAdd = new Emitter<MainThreadTextEditor>();
-		this._onTextEditorRemove = new Emitter<MainThreadTextEditor>();
-		this._onDidUpdateTextEditors = new Emitter<void>();
-		this._onDidChangeFocusedTextEditor = new Emitter<string>();
-		this._focusTracker = {
-			onGainedFocus: () => this._updateFocusedTextEditor(),
-			onLostFocus: () => this._updateFocusedTextEditor()
-		};
-
-		this._modelService.onModelAdded(this._onModelAdded, this, this._toDispose);
-		this._modelService.onModelRemoved(this._onModelRemoved, this, this._toDispose);
-
-		this._codeEditorService.onCodeEditorAdd(this._onCodeEditorAdd, this, this._toDispose);
-		this._codeEditorService.onCodeEditorRemove(this._onCodeEditorRemove, this, this._toDispose);
-
-		this._updateMapping = new RunOnceScheduler(() => this._doUpdateMapping(), 0);
-		this._toDispose.push(this._updateMapping);
-	}
-
-	public dispose(): void {
-		this._toDispose = dispose(this._toDispose);
-	}
-
-	private _onModelAdded(model: EditorCommon.IModel): void {
-		this._updateMapping.schedule();
-	}
-
-	private _onModelRemoved(model: EditorCommon.IModel): void {
-		this._updateMapping.schedule();
-	}
-
-	private _onCodeEditorAdd(codeEditor: EditorCommon.ICommonCodeEditor): void {
-		this._editorModelChangeListeners[codeEditor.getId()] = codeEditor.onDidChangeModel(_ => this._updateMapping.schedule());
-		this._updateMapping.schedule();
-	}
-
-	private _onCodeEditorRemove(codeEditor: EditorCommon.ICommonCodeEditor): void {
-		this._editorModelChangeListeners[codeEditor.getId()].dispose();
-		delete this._editorModelChangeListeners[codeEditor.getId()];
-		this._updateMapping.schedule();
-	}
-
-	private _doUpdateMapping(): void {
-		let allModels = this._modelService.getModels();
-		// Same filter as in extHostDocuments
-		allModels = allModels.filter((model) => !model.isTooLargeForHavingARichMode());
-		let allModelsMap: { [modelUri: string]: EditorCommon.IModel; } = Object.create(null);
-		allModels.forEach((model) => {
-			allModelsMap[model.uri.toString()] = model;
-		});
-
-		// Remove text editors for models that no longer exist
-		Object.keys(this._model2TextEditors).forEach((modelUri) => {
-			if (allModelsMap[modelUri]) {
-				// model still exists, will be updated below
-				return;
-			}
-
-			let textEditorsToRemove = this._model2TextEditors[modelUri];
-			delete this._model2TextEditors[modelUri];
-
-			for (let i = 0; i < textEditorsToRemove.length; i++) {
-				this._onTextEditorRemove.fire(textEditorsToRemove[i]);
-				textEditorsToRemove[i].dispose();
-			}
-		});
-
-		// Handle all visible models
-		let visibleModels = this._getVisibleModels();
-		Object.keys(visibleModels).forEach((modelUri) => {
-			let model = visibleModels[modelUri].model;
-			let codeEditors = visibleModels[modelUri].codeEditors;
-
-			if (!this._model2TextEditors[modelUri]) {
-				this._model2TextEditors[modelUri] = [];
-			}
-			let existingTextEditors = this._model2TextEditors[modelUri];
-
-			// Remove text editors if more exist
-			while (existingTextEditors.length > codeEditors.length) {
-				let removedTextEditor = existingTextEditors.pop();
-				this._onTextEditorRemove.fire(removedTextEditor);
-				removedTextEditor.dispose();
-			}
-
-			// Adjust remaining text editors
-			for (let i = 0; i < existingTextEditors.length; i++) {
-				existingTextEditors[i].setCodeEditor(codeEditors[i]);
-			}
-
-			// Create new editors as needed
-			for (let i = existingTextEditors.length; i < codeEditors.length; i++) {
-				let newTextEditor = new MainThreadTextEditor(MainThreadEditorsTracker._Ids.nextId(), model, codeEditors[i], this._focusTracker, this._modelService);
-				existingTextEditors.push(newTextEditor);
-				this._onTextEditorAdd.fire(newTextEditor);
-			}
-		});
-
-		// Handle all not visible models
-		allModels.forEach((model) => {
-			let modelUri = model.uri.toString();
-
-			if (visibleModels[modelUri]) {
-				// model is visible, already handled above
-				return;
-			}
-
-			if (!this._model2TextEditors[modelUri]) {
-				this._model2TextEditors[modelUri] = [];
-			}
-			let existingTextEditors = this._model2TextEditors[modelUri];
-
-			// Remove extra text editors
-			while (existingTextEditors.length > 1) {
-				let removedTextEditor = existingTextEditors.pop();
-				this._onTextEditorRemove.fire(removedTextEditor);
-				removedTextEditor.dispose();
-			}
-
-			// Create new editor if needed or adjust it
-			if (existingTextEditors.length === 0) {
-				let newTextEditor = new MainThreadTextEditor(MainThreadEditorsTracker._Ids.nextId(), model, null, this._focusTracker, this._modelService);
-				existingTextEditors.push(newTextEditor);
-				this._onTextEditorAdd.fire(newTextEditor);
-			} else {
-				existingTextEditors[0].setCodeEditor(null);
-			}
-		});
-
-		this._printState();
-
-		this._visibleTextEditorIds = this._findVisibleTextEditorIds();
-
-		this._updateFocusedTextEditor();
-
-		// this is a sync event
-		this._onDidUpdateTextEditors.fire(undefined);
-	}
-
-	private _updateFocusedTextEditor(): void {
-		this._setFocusedTextEditorId(this._findFocusedTextEditorId());
-	}
-
-	private _findFocusedTextEditorId(): string {
-		let modelUris = Object.keys(this._model2TextEditors);
-		for (let i = 0, len = modelUris.length; i < len; i++) {
-			let editors = this._model2TextEditors[modelUris[i]];
-			for (let j = 0, lenJ = editors.length; j < lenJ; j++) {
-				if (editors[j].isFocused()) {
-					return editors[j].getId();
-				}
-			}
-		}
-
-		return null;
-	}
-
-	private _findVisibleTextEditorIds(): string[] {
-		let result: string[] = [];
-		let modelUris = Object.keys(this._model2TextEditors);
-		for (let i = 0, len = modelUris.length; i < len; i++) {
-			let editors = this._model2TextEditors[modelUris[i]];
-			for (let j = 0, lenJ = editors.length; j < lenJ; j++) {
-				if (editors[j].isVisible()) {
-					result.push(editors[j].getId());
-				}
-			}
-		}
-		result.sort();
-		return result;
-	}
-
-	private _setFocusedTextEditorId(focusedTextEditorId: string): void {
-		if (this._focusedTextEditorId === focusedTextEditorId) {
-			// no change
-			return;
-		}
-
-		this._focusedTextEditorId = focusedTextEditorId;
-		this._printState();
-		this._onDidChangeFocusedTextEditor.fire(this._focusedTextEditorId);
-	}
-
-
-	private _printState(): void {
-		// console.log('----------------------');
-		// Object.keys(this._model2TextEditors).forEach((modelUri) => {
-		// 	let editors = this._model2TextEditors[modelUri];
-
-		// 	console.log(editors.map((e) => {
-		// 		return e.getId() + " (" + (e.getId() === this._focusedTextEditorId ? 'FOCUSED, ': '') + modelUri + ")";
-		// 	}).join('\n'));
-		// });
-	}
-
-	private _getVisibleModels(): IVisibleModels {
-		let r: IVisibleModels = {};
-
-		let allCodeEditors = this._codeEditorService.listCodeEditors();
-
-		// Maintain a certain sorting such that the mapping doesn't change too much all the time
-		allCodeEditors.sort((a, b) => strcmp(a.getId(), b.getId()));
-
-		allCodeEditors.forEach((codeEditor) => {
-			let model = codeEditor.getModel();
-			if (!model || model.isTooLargeForHavingARichMode() || !this._modelService.getModel(model.uri)) {
-				return;
-			}
-
-			let modelUri = model.uri.toString();
-			r[modelUri] = r[modelUri] || {
-				model: model,
-				codeEditors: []
-			};
-			r[modelUri].codeEditors.push(codeEditor);
-		});
-
-		return r;
-	}
-
-	public getFocusedTextEditorId(): string {
-		return this._focusedTextEditorId;
-	}
-
-	public getVisibleTextEditorIds(): string[] {
-		return this._visibleTextEditorIds;
-	}
-
-	public get onTextEditorAdd(): Event<MainThreadTextEditor> {
-		return this._onTextEditorAdd.event;
-	}
-
-	public get onTextEditorRemove(): Event<MainThreadTextEditor> {
-		return this._onTextEditorRemove.event;
-	}
-
-	public get onDidUpdateTextEditors(): Event<void> {
-		return this._onDidUpdateTextEditors.event;
-	}
-
-	public get onChangedFocusedTextEditor(): Event<string> {
-		return this._onDidChangeFocusedTextEditor.event;
-	}
-
-	public findTextEditorIdFor(codeEditor: EditorCommon.ICommonCodeEditor): string {
-		let modelUris = Object.keys(this._model2TextEditors);
-		for (let i = 0, len = modelUris.length; i < len; i++) {
-			let editors = this._model2TextEditors[modelUris[i]];
-			for (let j = 0, lenJ = editors.length; j < lenJ; j++) {
-				if (editors[j].hasCodeEditor(codeEditor)) {
-					return editors[j].getId();
-				}
-			}
-		}
-
-		return null;
-	}
-
-	public registerTextEditorDecorationType(key: string, options: EditorCommon.IDecorationRenderOptions): void {
-		this._codeEditorService.registerDecorationType(key, options);
-	}
-
-	public removeTextEditorDecorationType(key: string): void {
-		this._codeEditorService.removeDecorationType(key);
-	}
-}
-
-interface IVisibleModels {
-	[modelUri: string]: {
-		model: EditorCommon.IModel;
-		codeEditors: EditorCommon.ICommonCodeEditor[];
-	};
-}
-
-function strcmp(a: string, b: string): number {
-	if (a < b) {
-		return -1;
-	}
-	if (a > b) {
-		return 1;
-	}
-	return 0;
-}
-
--- a/src/vs/workbench/api/node/mainThreadEditors.ts
+++ b/src/vs/workbench/api/node/mainThreadEditors.ts
@@ -8,58 +8,47 @@ import URI from 'vs/base/common/uri';
 import { IDisposable, dispose } from 'vs/base/common/lifecycle';
 import { TPromise } from 'vs/base/common/winjs.base';
 import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
-import { ISingleEditOperation, ISelection, IRange, IEditor, EditorType, ICommonCodeEditor, ICommonDiffEditor, IDecorationRenderOptions, IDecorationOptions } from 'vs/editor/common/editorCommon';
+import { ISingleEditOperation, ISelection, IRange, IDecorationRenderOptions, IDecorationOptions } from 'vs/editor/common/editorCommon';
 import { ICodeEditorService } from 'vs/editor/common/services/codeEditorService';
 import { IWorkbenchEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { IEditorGroupService } from 'vs/workbench/services/group/common/groupService';
 import { Position as EditorPosition } from 'vs/platform/editor/common/editor';
-import { IModelService } from 'vs/editor/common/services/modelService';
-import { MainThreadEditorsTracker, TextEditorRevealType, MainThreadTextEditor, IApplyEditsOptions, IUndoStopOptions, ITextEditorConfigurationUpdate } from 'vs/workbench/api/node/mainThreadEditorsTracker';
+import { TextEditorRevealType, MainThreadTextEditor, IApplyEditsOptions, IUndoStopOptions, ITextEditorConfigurationUpdate } from 'vs/workbench/api/node/mainThreadEditor';
+import { MainThreadDocumentsAndEditors } from './mainThreadDocumentsAndEditors';
 import { ITelemetryService } from 'vs/platform/telemetry/common/telemetry';
-import { equals as arrayEquals } from 'vs/base/common/arrays';
 import { equals as objectEquals } from 'vs/base/common/objects';
 import { ExtHostContext, MainThreadEditorsShape, ExtHostEditorsShape, ITextEditorPositionData } from './extHost.protocol';

 export class MainThreadEditors extends MainThreadEditorsShape {

 	private _proxy: ExtHostEditorsShape;
+	private _documentsAndEditors: MainThreadDocumentsAndEditors;
 	private _workbenchEditorService: IWorkbenchEditorService;
 	private _telemetryService: ITelemetryService;
-	private _editorTracker: MainThreadEditorsTracker;
 	private _toDispose: IDisposable[];
 	private _textEditorsListenersMap: { [editorId: string]: IDisposable[]; };
-	private _textEditorsMap: { [editorId: string]: MainThreadTextEditor; };
-	private _activeTextEditor: string;
-	private _visibleEditors: string[];
 	private _editorPositionData: ITextEditorPositionData;

 	constructor(
+		documentsAndEditors: MainThreadDocumentsAndEditors,
+		@ICodeEditorService private _codeEditorService: ICodeEditorService,
 		@IThreadService threadService: IThreadService,
 		@IWorkbenchEditorService workbenchEditorService: IWorkbenchEditorService,
 		@IEditorGroupService editorGroupService: IEditorGroupService,
-		@ITelemetryService telemetryService: ITelemetryService,
-		@ICodeEditorService editorService: ICodeEditorService,
-		@IModelService modelService: IModelService
+		@ITelemetryService telemetryService: ITelemetryService
 	) {
 		super();
 		this._proxy = threadService.get(ExtHostContext.ExtHostEditors);
+		this._documentsAndEditors = documentsAndEditors;
 		this._workbenchEditorService = workbenchEditorService;
 		this._telemetryService = telemetryService;
 		this._toDispose = [];
 		this._textEditorsListenersMap = Object.create(null);
-		this._textEditorsMap = Object.create(null);
-		this._activeTextEditor = null;
-		this._visibleEditors = [];
 		this._editorPositionData = null;

-		this._editorTracker = new MainThreadEditorsTracker(editorService, modelService);
-		this._toDispose.push(this._editorTracker);
+		this._toDispose.push(documentsAndEditors.onTextEditorAdd(editors => editors.forEach(this._onTextEditorAdd, this)));
+		this._toDispose.push(documentsAndEditors.onTextEditorRemove(editors => editors.forEach(this._onTextEditorRemove, this)));

-		this._toDispose.push(this._editorTracker.onTextEditorAdd((textEditor) => this._onTextEditorAdd(textEditor)));
-		this._toDispose.push(this._editorTracker.onTextEditorRemove((textEditor) => this._onTextEditorRemove(textEditor)));
-
-		this._toDispose.push(this._editorTracker.onDidUpdateTextEditors(() => this._updateActiveAndVisibleTextEditors()));
-		this._toDispose.push(this._editorTracker.onChangedFocusedTextEditor((focusedTextEditorId) => this._updateActiveAndVisibleTextEditors()));
 		this._toDispose.push(editorGroupService.onEditorsChanged(() => this._updateActiveAndVisibleTextEditors()));
 		this._toDispose.push(editorGroupService.onEditorsMoved(() => this._updateActiveAndVisibleTextEditors()));
 	}
@@ -81,37 +70,17 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 		toDispose.push(textEditor.onSelectionChanged((event) => {
 			this._proxy.$acceptSelectionsChanged(id, event);
 		}));
-		this._proxy.$acceptTextEditorAdd({
-			id: id,
-			document: textEditor.getModel().uri,
-			options: textEditor.getConfiguration(),
-			selections: textEditor.getSelections(),
-			editorPosition: this._findEditorPosition(textEditor)
-		});

 		this._textEditorsListenersMap[id] = toDispose;
-		this._textEditorsMap[id] = textEditor;
 	}

-	private _onTextEditorRemove(textEditor: MainThreadTextEditor): void {
-		let id = textEditor.getId();
+	private _onTextEditorRemove(id: string): void {
 		dispose(this._textEditorsListenersMap[id]);
 		delete this._textEditorsListenersMap[id];
-		delete this._textEditorsMap[id];
-		this._proxy.$acceptTextEditorRemove(id);
 	}

 	private _updateActiveAndVisibleTextEditors(): void {

-		// active and visible editors
-		let visibleEditors = this._editorTracker.getVisibleTextEditorIds();
-		let activeEditor = this._findActiveTextEditorId();
-		if (activeEditor !== this._activeTextEditor || !arrayEquals(this._visibleEditors, visibleEditors, (a, b) => a === b)) {
-			this._activeTextEditor = activeEditor;
-			this._visibleEditors = visibleEditors;
-			this._proxy.$acceptActiveEditorAndVisibleEditors(this._activeTextEditor, this._visibleEditors);
-		}
-
 		// editor columns
 		let editorPositionData = this._getTextEditorPositionData();
 		if (!objectEquals(this._editorPositionData, editorPositionData)) {
@@ -120,55 +89,12 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 		}
 	}

-	private _findActiveTextEditorId(): string {
-		let focusedTextEditorId = this._editorTracker.getFocusedTextEditorId();
-		if (focusedTextEditorId) {
-			return focusedTextEditorId;
-		}
-
-		let activeEditor = this._workbenchEditorService.getActiveEditor();
-		if (!activeEditor) {
-			return null;
-		}
-
-		let editor = <IEditor>activeEditor.getControl();
-		// Substitute for (editor instanceof ICodeEditor)
-		if (!editor || typeof editor.getEditorType !== 'function') {
-			// Not a text editor...
-			return null;
-		}
-
-		if (editor.getEditorType() === EditorType.ICodeEditor) {
-			return this._editorTracker.findTextEditorIdFor(<ICommonCodeEditor>editor);
-		}
-
-		// Must be a diff editor => use the modified side
-		return this._editorTracker.findTextEditorIdFor((<ICommonDiffEditor>editor).getModifiedEditor());
-	}
-
-	private _findEditorPosition(editor: MainThreadTextEditor): EditorPosition {
-		for (let workbenchEditor of this._workbenchEditorService.getVisibleEditors()) {
-			if (editor.matches(workbenchEditor)) {
-				return workbenchEditor.position;
-			}
-		}
-		return undefined;
-	}
-
 	private _getTextEditorPositionData(): ITextEditorPositionData {
 		let result: ITextEditorPositionData = Object.create(null);
 		for (let workbenchEditor of this._workbenchEditorService.getVisibleEditors()) {
-			let editor = <IEditor>workbenchEditor.getControl();
-			// Substitute for (editor instanceof ICodeEditor)
-			if (!editor || typeof editor.getEditorType !== 'function') {
-				// Not a text editor...
-				continue;
-			}
-			if (editor.getEditorType() === EditorType.ICodeEditor) {
-				let id = this._editorTracker.findTextEditorIdFor(<ICommonCodeEditor>editor);
-				if (id) {
-					result[id] = workbenchEditor.position;
-				}
+			const id = this._documentsAndEditors.findTextEditorIdFor(workbenchEditor);
+			if (id) {
+				result[id] = workbenchEditor.position;
 			}
 		}
 		return result;
@@ -187,43 +113,7 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 			if (!editor) {
 				return undefined;
 			}
-
-			const findEditor = (): string => {
-				// find the editor we have just opened and return the
-				// id we have assigned to it.
-				for (let id in this._textEditorsMap) {
-					if (this._textEditorsMap[id].matches(editor)) {
-						return id;
-					}
-				}
-				return undefined;
-			};
-
-			const syncEditorId = findEditor();
-			if (syncEditorId) {
-				return TPromise.as(syncEditorId);
-			}
-
-			return new TPromise<void>(resolve => {
-				// not very nice but the way it is: changes to the editor state aren't
-				// send to the ext host as they happen but stuff is delayed a little. in
-				// order to provide the real editor on #openTextEditor we need to sync on
-				// that update
-				let subscription: IDisposable;
-				let handle: number;
-				function contd() {
-					subscription.dispose();
-					clearTimeout(handle);
-					resolve(undefined);
-				}
-				subscription = this._editorTracker.onDidUpdateTextEditors(() => {
-					contd();
-				});
-				handle = setTimeout(() => {
-					contd();
-				}, 1000);
-
-			}).then(findEditor);
+			return this._documentsAndEditors.findTextEditorIdFor(editor);
 		});
 	}

@@ -231,7 +121,7 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 		// check how often this is used
 		this._telemetryService.publicLog('api.deprecated', { function: 'TextEditor.show' });

-		let mainThreadEditor = this._textEditorsMap[id];
+		let mainThreadEditor = this._documentsAndEditors.getEditor(id);
 		if (mainThreadEditor) {
 			let model = mainThreadEditor.getModel();
 			return this._workbenchEditorService.openEditor({
@@ -246,7 +136,7 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 		// check how often this is used
 		this._telemetryService.publicLog('api.deprecated', { function: 'TextEditor.hide' });

-		let mainThreadEditor = this._textEditorsMap[id];
+		let mainThreadEditor = this._documentsAndEditors.getEditor(id);
 		if (mainThreadEditor) {
 			let editors = this._workbenchEditorService.getVisibleEditors();
 			for (let editor of editors) {
@@ -259,56 +149,57 @@ export class MainThreadEditors extends MainThreadEditorsShape {
 	}

 	$trySetSelections(id: string, selections: ISelection[]): TPromise<any> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		this._textEditorsMap[id].setSelections(selections);
+		this._documentsAndEditors.getEditor(id).setSelections(selections);
 		return TPromise.as(null);
 	}

 	$trySetDecorations(id: string, key: string, ranges: IDecorationOptions[]): TPromise<any> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		this._textEditorsMap[id].setDecorations(key, ranges);
+		this._documentsAndEditors.getEditor(id).setDecorations(key, ranges);
 		return TPromise.as(null);
 	}

 	$tryRevealRange(id: string, range: IRange, revealType: TextEditorRevealType): TPromise<any> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		this._textEditorsMap[id].revealRange(range, revealType);
+		this._documentsAndEditors.getEditor(id).revealRange(range, revealType);
 		return undefined;
 	}

 	$trySetOptions(id: string, options: ITextEditorConfigurationUpdate): TPromise<any> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		this._textEditorsMap[id].setConfiguration(options);
+		this._documentsAndEditors.getEditor(id).setConfiguration(options);
 		return TPromise.as(null);
 	}

 	$tryApplyEdits(id: string, modelVersionId: number, edits: ISingleEditOperation[], opts: IApplyEditsOptions): TPromise<boolean> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		return TPromise.as(this._textEditorsMap[id].applyEdits(modelVersionId, edits, opts));
+		return TPromise.as(this._documentsAndEditors.getEditor(id).applyEdits(modelVersionId, edits, opts));
 	}

 	$tryInsertSnippet(id: string, template: string, ranges: IRange[], opts: IUndoStopOptions): TPromise<boolean> {
-		if (!this._textEditorsMap[id]) {
+		if (!this._documentsAndEditors.getEditor(id)) {
 			return TPromise.wrapError('TextEditor disposed');
 		}
-		return TPromise.as(this._textEditorsMap[id].insertSnippet(template, ranges, opts));
+		return TPromise.as(this._documentsAndEditors.getEditor(id).insertSnippet(template, ranges, opts));
 	}

 	$registerTextEditorDecorationType(key: string, options: IDecorationRenderOptions): void {
-		this._editorTracker.registerTextEditorDecorationType(key, options);
+		this._codeEditorService.registerDecorationType(key, options);
 	}

 	$removeTextEditorDecorationType(key: string): void {
-		this._editorTracker.removeTextEditorDecorationType(key);
+		this._codeEditorService.removeDecorationType(key);
+
 	}
 }