extension.js

// Dependencies
const fs = require("fs").promises
const vscode = require("vscode")
const ignore = require("ignore")
const path = require("path")

// Core
class GitignoreDecorationProvider {
	constructor() {
		this._onDidChangeFileDecorations = new vscode.EventEmitter()
		this.onDidChangeFileDecorations = this._onDidChangeFileDecorations.event
		this.ignoreCaches = new Map()
		this.sortedCaches = []
		this.watchers = []
		this.init().catch((err)=>{
			console.log("Error:", err)
		})
	}

	async init() {
		await this.refreshIgnoreCaches()
		this.setupWatchers()
	}

	async refreshIgnoreCaches() {
		this.ignoreCaches.clear()
		const workspaceFolders = vscode.workspace.workspaceFolders
		if (!workspaceFolders) return

		const ignoreFiles = await vscode.workspace.findFiles("**/.gitignore", "**/node_modules/**")
		for (const file of ignoreFiles) await this.loadGitignore(file.fsPath)
		this.updateSortedCaches()
		this._onDidChangeFileDecorations.fire(undefined)
	}

	async loadGitignore(gitignorePath) {
		try {
			const content = await fs.readFile(gitignorePath, "utf8")
			const ig = ignore().add(content)
			this.ignoreCaches.set(path.dirname(gitignorePath), {
				ig,
				path: gitignorePath
			})
		} catch  {
			console.log(`Error loading gitignore ${gitignorePath}:`, err)
		}
	}

	updateSortedCaches() {
		this.sortedCaches = Array.from(this.ignoreCaches.entries()).sort((a, b) => b[0].length - a[0].length)
	}

	setupWatchers() {
		this.watchers.forEach(w => w.dispose())
		this.watchers = []

		const watcher = vscode.workspace.createFileSystemWatcher("**/.gitignore")
		watcher.onDidCreate(uri => this.handleGitignoreChange(uri))
		watcher.onDidChange(uri => this.handleGitignoreChange(uri))
		watcher.onDidDelete(uri => this.handleGitignoreDelete(uri))
		this.watchers.push(watcher)

		const workspaceWatcher = vscode.workspace.onDidChangeWorkspaceFolders(() => this.refreshIgnoreCaches())
		this.watchers.push(workspaceWatcher)
	}

	async handleGitignoreChange(uri) {
		await this.loadGitignore(uri.fsPath)
		this.updateSortedCaches()
		this._onDidChangeFileDecorations.fire(undefined)
	}

	handleGitignoreDelete(uri) {
		this.ignoreCaches.delete(path.dirname(uri.fsPath))
		this.updateSortedCaches()
		this._onDidChangeFileDecorations.fire(undefined)
	}

	provideFileDecoration(uri) {
		if (uri.scheme !== "file") return

		const fsPath = uri.fsPath
		
		for (const [dir, cache] of this.sortedCaches) {
			if (fsPath.startsWith(dir)) {
				const relativePath = path.relative(dir, fsPath)
				if (relativePath && !relativePath.startsWith("..")) {
					const normalizedPath = relativePath.split(path.sep).join("/")
					
					const result = cache.ig.test(normalizedPath)
					if (result.ignored) {
						return {
							badge: "GI",
							tooltip: "Ignored by .gitignore",
							color: new vscode.ThemeColor("errorForeground"),
							propagate: true
						}
					} else if (result.unignored) {
						return null
					}
				}
			}
		}
		return null
	}

	dispose() {
		this.watchers.forEach(w => w.dispose())
		this._onDidChangeFileDecorations.dispose()
	}
}

// Main
/**
 * @param {vscode.ExtensionContext} context
 */
function activate(context) {
	console.log("gitignore-marker is now active.")
	const decorationProvider = new GitignoreDecorationProvider()
	context.subscriptions.push(vscode.window.registerFileDecorationProvider(decorationProvider))
	context.subscriptions.push(decorationProvider)
	const refreshCommand = vscode.commands.registerCommand("gitignore-marker.refresh", () => {
		decorationProvider.refreshIgnoreCaches()
	})
	context.subscriptions.push(refreshCommand)
}

function deactivate() {}

module.exports = {
	activate,
	deactivate
}