Open readonly files as readonly editors

src/vs/workbench/browser/parts/editor/textDiffEditor.ts

@@ -118,7 +118,8 @@ export class TextDiffEditor extends BaseTextEditor implements ITextDiffEditor {
 
 				// Set Editor Model
 				const diffEditor = this.getControl();
-				diffEditor.setModel((<TextDiffEditorModel>resolvedModel).textDiffEditorModel);
+				const resolvedDiffEditorModel = <TextDiffEditorModel>resolvedModel;
+				diffEditor.setModel(resolvedDiffEditorModel.textDiffEditorModel);
 
 				// Apply Options from TextOptions
 				let optionsGotApplied = false;
@@ -142,6 +143,8 @@ export class TextDiffEditor extends BaseTextEditor implements ITextDiffEditor {
 					this.previousDiffAction.updateEnablement();
 				}));
 
+				this.getControl().updateOptions({ readOnly: resolvedDiffEditorModel.isReadonly() });
+
 				this.updateIgnoreTrimWhitespaceAction();
 			}, error => {
 

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

@@ -66,6 +66,10 @@ export class TextDiffEditorModel extends DiffEditorModel {
 		return !!this._textDiffEditorModel;
 	}
 
+	public isReadonly(): boolean {
+		return this.modifiedModel.isReadonly();
+	}
+
 	public dispose(): void {
 
 		// Free the diff editor model but do not propagate the dispose() call to the two models
@@ -76,4 +80,4 @@ export class TextDiffEditorModel extends DiffEditorModel {
 
 		super.dispose();
 	}
-}
+}

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

@@ -137,6 +137,10 @@ export abstract class BaseTextEditorModel extends EditorModel implements ITextEd
 		return !!this.textEditorModelHandle;
 	}
 
+	public isReadonly(): boolean {
+		return false;
+	}
+
 	public dispose(): void {
 		if (this.modelDisposeListener) {
 			this.modelDisposeListener.dispose(); // dispose this first because it will trigger another dispose() otherwise

src/vs/workbench/parts/files/browser/editors/textFileEditor.ts

@@ -146,6 +146,8 @@ export class TextFileEditor extends BaseTextEditor {
 				if (options && types.isFunction((<TextEditorOptions>options).apply)) {
 					(<TextEditorOptions>options).apply(textEditor, ScrollType.Immediate);
 				}
+
+				textEditor.updateOptions({ readOnly: textFileModel.isReadonly() });
 			}, error => {
 
 				// In case we tried to open a file inside the text editor and the response

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

@@ -698,7 +698,7 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 			// be disposed if we are dirty, but if we are not dirty, save() and dispose() can still be triggered
 			// one after the other without waiting for the save() to complete. If we are disposed(), we risk
 			// saving contents to disk that are stale (see https://github.com/Microsoft/vscode/issues/50942).
-			// To fix this issue, we will not store the contents to disk when we got disposed. 
+			// To fix this issue, we will not store the contents to disk when we got disposed.
 			if (this.disposed) {
 				return void 0;
 			}
@@ -983,6 +983,10 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 		return !types.isUndefinedOrNull(this.lastResolvedDiskStat);
 	}
 
+	public isReadonly(): boolean {
+		return this.lastResolvedDiskStat.isReadonly;
+	}
+
 	/**
 	 * Returns true if the dispose() method of this model has been called.
 	 */

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

@@ -232,6 +232,8 @@ export interface ITextFileEditorModel extends ITextEditorModel, IEncodingSupport
 
 	isResolved(): boolean;
 
+	isReadonly(): boolean;
+
 	isDisposed(): boolean;
 }