Caching code cleanup

font-src/caching/index.js

@@ -0,0 +1,46 @@
+"use strict";
+
+const fs = require("fs-extra");
+const zlib = require("zlib");
+
+const EDITION = "Iosevka.PTCache.1";
+
+class Cache {
+	constructor() {
+		this.ptSource = {};
+		this.ptSink = {};
+	}
+	loadRep(rep) {
+		if (!rep || rep.edition !== EDITION) return;
+		this.ptSource = rep.pt;
+	}
+	toRep() {
+		return { edition: EDITION, pt: this.ptSink };
+	}
+	// Path conversion cache
+	getPT(ck) {
+		return this.ptSource[ck];
+	}
+	savePT(ck, val) {
+		this.ptSink[ck] = val;
+	}
+}
+
+exports.load = async function (argv) {
+	let cache = new Cache();
+	if (argv.oCache && fs.existsSync(argv.oCache)) {
+		cache.loadRep(unzip(await fs.readFile(argv.oCache)));
+	}
+	return cache;
+};
+
+exports.save = async function savePTCache(argv, cache) {
+	if (argv.oCache) await fs.writeFile(argv.oCache, zip(cache.toRep()));
+};
+
+function unzip(buf) {
+	return JSON.parse(zlib.gunzipSync(buf));
+}
+function zip(obj) {
+	return zlib.gzipSync(Buffer.from(JSON.stringify(obj), "utf-8"));
+}