Merge pull request #38683 from Microsoft/ben/30032

cache icon data optimistically like color themes

src/vs/workbench/services/themes/electron-browser/fileIconThemeData.ts

@@ -77,6 +77,39 @@ export class FileIconThemeData implements IFileIconTheme {
 		}
 		return themeData;
 	}
+
+	static fromStorageData(input: string): FileIconThemeData {
+		try {
+			let data = JSON.parse(input);
+			let theme = new FileIconThemeData();
+			for (let key in data) {
+				switch (key) {
+					case 'id':
+					case 'label':
+					case 'description':
+					case 'settingsId':
+					case 'extensionData':
+					case 'path':
+						theme[key] = data[key];
+						break;
+				}
+			}
+			return theme;
+		} catch (e) {
+			return null;
+		}
+	}
+
+	toStorageData() {
+		return JSON.stringify({
+			id: this.id,
+			label: this.label,
+			description: this.description,
+			settingsId: this.settingsId,
+			path: this.path,
+			extensionData: this.extensionData
+		});
+	}
 }
 
 interface IconDefinition {

src/vs/workbench/services/themes/electron-browser/workbenchThemeService.ts

@@ -38,6 +38,7 @@ const DEFAULT_THEME_ID = 'vs-dark vscode-theme-defaults-themes-dark_plus-json';
 const DEFAULT_THEME_SETTING_VALUE = 'Default Dark+';
 
 const PERSISTED_THEME_STORAGE_KEY = 'colorThemeData';
+const PERSISTED_ICON_THEME_STORAGE_KEY = 'iconThemeData';
 
 const defaultThemeExtensionId = 'vscode-theme-defaults';
 const oldDefaultThemeExtensionId = 'vscode-theme-colorful-defaults';
@@ -132,6 +133,20 @@ export class WorkbenchThemeService implements IWorkbenchThemeService {
 		this.updateDynamicCSSRules(themeData);
 		this.applyTheme(themeData, null, true);
 
+		let iconData: FileIconThemeData = null;
+		let persistedIconThemeData = this.storageService.get(PERSISTED_ICON_THEME_STORAGE_KEY);
+		if (persistedIconThemeData) {
+			iconData = FileIconThemeData.fromStorageData(persistedIconThemeData);
+
+			if (iconData) {
+				_applyIconTheme(iconData, () => {
+					this.doSetFileIconTheme(iconData);
+
+					return TPromise.wrap(iconData);
+				});
+			}
+		}
+
 		this.initialize().then(null, errors.onUnexpectedError).then(_ => {
 			this.installConfigurationListener();
 		});
@@ -353,23 +368,15 @@ export class WorkbenchThemeService implements IWorkbenchThemeService {
 			return this.writeFileIconConfiguration(settingsTarget);
 		}
 		let onApply = (newIconTheme: FileIconThemeData) => {
+			this.doSetFileIconTheme(newIconTheme);
+
+			// remember theme data for a quick restore
 			if (newIconTheme) {
-				this.currentIconTheme = newIconTheme;
+				this.storageService.store(PERSISTED_ICON_THEME_STORAGE_KEY, newIconTheme.toStorageData());
 			} else {
-				this.currentIconTheme = FileIconThemeData.noIconTheme();
+				this.storageService.remove(PERSISTED_ICON_THEME_STORAGE_KEY);
 			}
 
-			if (this.container) {
-				if (newIconTheme) {
-					$(this.container).addClass(fileIconsEnabledClass);
-				} else {
-					$(this.container).removeClass(fileIconsEnabledClass);
-				}
-			}
-			if (newIconTheme) {
-				this.sendTelemetry(newIconTheme.id, newIconTheme.extensionData, 'fileIcon');
-			}
-			this.onFileIconThemeChange.fire(this.currentIconTheme);
 			return this.writeFileIconConfiguration(settingsTarget);
 		};
 
@@ -378,6 +385,27 @@ export class WorkbenchThemeService implements IWorkbenchThemeService {
 		});
 	}
 
+	private doSetFileIconTheme(iconThemeData: FileIconThemeData): void {
+		if (iconThemeData) {
+			this.currentIconTheme = iconThemeData;
+		} else {
+			this.currentIconTheme = FileIconThemeData.noIconTheme();
+		}
+
+		if (this.container) {
+			if (iconThemeData) {
+				$(this.container).addClass(fileIconsEnabledClass);
+			} else {
+				$(this.container).removeClass(fileIconsEnabledClass);
+			}
+		}
+		if (iconThemeData) {
+			this.sendTelemetry(iconThemeData.id, iconThemeData.extensionData, 'fileIcon');
+		}
+		this.onFileIconThemeChange.fire(this.currentIconTheme);
+
+	}
+
 	private writeFileIconConfiguration(settingsTarget: ConfigurationTarget): TPromise<IFileIconTheme> {
 		if (!types.isUndefinedOrNull(settingsTarget)) {
 			return this.configurationWriter.writeConfiguration(ICON_THEME_SETTING, this.currentIconTheme.settingsId, settingsTarget).then(_ => this.currentIconTheme);