use IRawText and compare before pretending things have changed, #18664

src/vs/workbench/api/node/extHost.protocol.ts

@@ -122,7 +122,7 @@ export abstract class MainThreadDocumentsShape {
 	$tryCreateDocument(options?: { language: string; }): TPromise<any> { throw ni(); }
 	$tryOpenDocument(uri: URI): TPromise<any> { throw ni(); }
 	$registerTextContentProvider(handle: number, scheme: string): void { throw ni(); }
-	$onVirtualDocumentChange(uri: URI, value: string): void { throw ni(); }
+	$onVirtualDocumentChange(uri: URI, value: editorCommon.IRawText): void { throw ni(); }
 	$unregisterTextContentProvider(handle: number): void { throw ni(); }
 	$trySaveDocument(uri: URI): TPromise<boolean> { throw ni(); }
 }

src/vs/workbench/api/node/extHostDocuments.ts

@@ -7,6 +7,7 @@
 import { onUnexpectedError } from 'vs/base/common/errors';
 import { regExpLeadsToEndlessLoop } from 'vs/base/common/strings';
 import * as editorCommon from 'vs/editor/common/editorCommon';
+import { RawText } from 'vs/editor/common/model/textModel';
 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';
@@ -126,7 +127,27 @@ export class ExtHostDocuments extends ExtHostDocumentsShape {
 			subscription = provider.onDidChange(uri => {
 				if (this._documentData.has(uri.toString())) {
 					this.$provideTextDocumentContent(handle, <URI>uri).then(value => {
-						return this._proxy.$onVirtualDocumentChange(<URI>uri, value);
+
+						const document = this._documentData.get(uri.toString());
+						if (!document) {
+							// disposed in the meantime
+							return;
+						}
+
+						// create lines and compare
+						const raw = RawText.fromString(value, {
+							defaultEOL: editorCommon.DefaultEndOfLine.CRLF,
+							tabSize: 0,
+							detectIndentation: false,
+							insertSpaces: false,
+							trimAutoWhitespace: false
+						});
+
+						// broadcast event when content changed
+						if (!document.equalLines(raw)) {
+							return this._proxy.$onVirtualDocumentChange(<URI>uri, raw);
+						}
+
 					}, onUnexpectedError);
 				}
 			});
@@ -241,6 +262,19 @@ export class ExtHostDocumentData extends MirrorModel2 {
 		super.dispose();
 	}
 
+	equalLines({lines}: editorCommon.IRawText): 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;

src/vs/workbench/api/node/mainThreadDocuments.ts

@@ -8,6 +8,7 @@ import { toErrorMessage } from 'vs/base/common/errorMessage';
 import { EmitterEvent } from 'vs/base/common/eventEmitter';
 import { IModelService } from 'vs/editor/common/services/modelService';
 import * as editorCommon from 'vs/editor/common/editorCommon';
+import { RawText } from 'vs/editor/common/model/textModel';
 import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
 import URI from 'vs/base/common/uri';
 import { IDisposable, dispose } from 'vs/base/common/lifecycle';
@@ -237,10 +238,26 @@ export class MainThreadDocuments extends MainThreadDocumentsShape {
 		}
 	}
 
-	$onVirtualDocumentChange(uri: URI, value: string): void {
+	$onVirtualDocumentChange(uri: URI, value: editorCommon.IRawText): void {
 		const model = this._modelService.getModel(uri);
-		if (model) {
-			model.setValue(value);
+		if (!model) {
+			return;
+		}
+		// fetch the raw text from the ext host but
+		// reuse the current options
+		const {options} = RawText.fromStringWithModelOptions('', model);
+		const raw = <editorCommon.IRawText>{
+			options,
+			lines: value.lines,
+			length: value.length,
+			BOM: value.BOM,
+			EOL: value.EOL,
+			containsRTL: value.containsRTL,
+			isBasicASCII: value.isBasicASCII,
+		};
+
+		if (!model.equals(raw)) {
+			model.setValueFromRawText(raw);
 		}
 	}
 }