snapshot support for getFirstLineText

src/vs/workbench/common/editor/textEditorModel.ts

@@ -91,7 +91,9 @@ export abstract class BaseTextEditorModel extends EditorModel implements ITextEd
 		return this;
 	}
 
-	protected getFirstLineText(value: string | ITextBufferFactory): string {
+	protected getFirstLineText(value: string | ITextBufferFactory | ITextSnapshot): string {
+
+		// string
 		if (typeof value === 'string') {
 			const firstLineText = value.substr(0, 100);
 
@@ -106,9 +108,17 @@ export abstract class BaseTextEditorModel extends EditorModel implements ITextEd
 			}
 
 			return firstLineText.substr(0, Math.min(crIndex, lfIndex));
-		} else {
-			return value.getFirstLineText(100);
 		}
+
+		// text buffer factory
+		const textBufferFactory = value as ITextBufferFactory;
+		if (typeof textBufferFactory.getFirstLineText === 'function') {
+			return textBufferFactory.getFirstLineText(100);
+		}
+
+		// text snapshot
+		const textSnapshot = value as ITextSnapshot;
+		return this.getFirstLineText(textSnapshot.read() || '');
 	}
 
 	/**

src/vs/workbench/common/editor/untitledEditorModel.ts

@@ -10,7 +10,6 @@ import { IEncodingSupport } from 'vs/workbench/common/editor';
 import { BaseTextEditorModel } from 'vs/workbench/common/editor/textEditorModel';
 import URI from 'vs/base/common/uri';
 import { PLAINTEXT_MODE_ID } from 'vs/editor/common/modes/modesRegistry';
-import { EndOfLinePreference } from 'vs/editor/common/model';
 import { CONTENT_CHANGE_EVENT_BUFFER_DELAY } from 'vs/platform/files/common/files';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { IModelService } from 'vs/editor/common/services/modelService';
@@ -113,14 +112,6 @@ export class UntitledEditorModel extends BaseTextEditorModel implements IEncodin
 		return this.versionId;
 	}
 
-	public getValue(): string {
-		if (this.textEditorModel) {
-			return this.textEditorModel.getValue(EndOfLinePreference.TextDefined, true /* Preserve BOM */);
-		}
-
-		return null;
-	}
-
 	public getModeId(): string {
 		if (this.textEditorModel) {
 			return this.textEditorModel.getLanguageIdentifier().language;

src/vs/workbench/services/textfile/common/textFileEditorModel.ts

@@ -188,7 +188,7 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 			return;
 		}
 
-		const firstLineText = this.getFirstLineText(this.textEditorModel.getValue());
+		const firstLineText = this.getFirstLineText(this.textEditorModel.createSnapshot());
 		const mode = this.getOrCreateMode(this.modeService, modeId, firstLineText);
 
 		this.modelService.setMode(this.textEditorModel, mode);