first cut/experiment of icon/resouce loading, #75061

src/vs/workbench/browser/web.main.ts

@@ -29,6 +29,7 @@ import { IWorkspaceInitializationPayload } from 'vs/platform/workspaces/common/w
 import { WorkspaceService } from 'vs/workbench/services/configuration/browser/configurationService';
 import { ConfigurationCache } from 'vs/workbench/services/configuration/browser/configurationCache';
 import { ConfigurationFileService } from 'vs/workbench/services/configuration/common/configuration';
+import { WebResources } from 'vs/workbench/browser/web.resources';
 
 interface IWindowConfiguration {
 	settingsUri: URI;
@@ -61,6 +62,9 @@ class CodeRendererMain extends Disposable {
 		// Layout
 		this._register(addDisposableListener(window, EventType.RESIZE, () => this.workbench.layout()));
 
+		// Resource Loading
+		this._register(new WebResources(<IFileService>services.serviceCollection.get(IFileService)));
+
 		// Workbench Lifecycle
 		this._register(this.workbench.onShutdown(() => this.dispose()));
 
@@ -188,4 +192,4 @@ function toResource(path: string): URI {
 		authority: document.location.host,
 		path
 	});
-}
\ No newline at end of file
+}

src/vs/workbench/browser/web.resources.ts

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { IFileService } from 'vs/platform/files/common/files';
+import { URI } from 'vs/base/common/uri';
+
+export class WebResources {
+
+	private readonly _regexp = /url\(('|")?(vscode-remote:\/\/.*?)\1\)/g;
+	private readonly _cache = new Map<string, string>();
+	private readonly _observer: MutationObserver;
+
+	constructor(@IFileService private readonly _fileService: IFileService) {
+		this._observer = new MutationObserver(r => this._handleMutation(r));
+
+		// todo@joh add observer to more than head-element
+		// todo@joh explore alternative approach
+		this._observer.observe(document.head, { subtree: true, childList: true });
+	}
+
+	dispose(): void {
+		this._observer.disconnect();
+		this._cache.forEach(value => URL.revokeObjectURL(value));
+	}
+
+	private _handleMutation(records: MutationRecord[]): void {
+		for (const record of records) {
+			if (record.target.nodeName === 'STYLE') {
+				// style-element directly modified
+				this._handleStyleNode(record.target);
+
+			} else if (record.target.nodeName === 'HEAD' && record.type === 'childList') {
+				// style-element added to head
+				record.addedNodes.forEach(node => {
+					if (node.nodeName === 'STYLE') {
+						this._handleStyleNode(node);
+					}
+				});
+			}
+		}
+	}
+
+	private _handleStyleNode(target: Node): void {
+
+		if (!target.textContent) {
+			return;
+		}
+
+		const positions: number[] = [];
+		const promises: Promise<any>[] = [];
+
+		let match: RegExpMatchArray | null = null;
+		while (match = this._regexp.exec(target.textContent)) {
+
+			const remoteUrl = match[2];
+			positions.push(match.index! + 'url('.length + match[1].length);
+			positions.push(remoteUrl.length);
+
+			if (this._cache.has(remoteUrl)) {
+				promises.push(Promise.resolve());
+
+			} else {
+				promises.push(this._fileService.readFile(URI.parse(remoteUrl, true)).then(file => {
+					// todo@joh hack
+					const type = /\.woff$/.test(remoteUrl) ? 'application/font-woff' : 'image/svg+xml';
+					this._cache.set(remoteUrl, URL.createObjectURL(new Blob([file.value.buffer], { type })));
+				}));
+			}
+		}
+
+		if (promises.length === 0) {
+			return;
+		}
+
+		let content = target.textContent;
+
+		Promise.all(promises).then(() => {
+
+			if (target.textContent !== content) {
+				return;
+			}
+
+			for (let i = positions.length - 1; i >= 0; i -= 2) {
+				const start = positions[i - 1];
+				const len = positions[i];
+				const url = this._cache.get(content.substr(start, len));
+				content = content.substring(0, start) + url + content.substring(start + len);
+			}
+
+			target.textContent = content;
+
+		}).catch(e => {
+			console.error(e);
+		});
+	}
+}