From f25eb48f795cafd63045b05ace75de2f63dfa51e Mon Sep 17 00:00:00 2001
From: TC <th-ch@users.noreply.github.com>
Date: Sun, 12 Apr 2020 14:17:38 +0200
Subject: [PATCH] Generate the adblocker engine only once (by using built-in
 caching)

---
 package.json                 |  3 ++-
 plugins/adblocker/.gitignore |  1 +
 plugins/adblocker/back.js    | 14 ++------------
 plugins/adblocker/blocker.js | 33 +++++++++++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 13 deletions(-)
 create mode 100644 plugins/adblocker/.gitignore
 create mode 100644 plugins/adblocker/blocker.js

diff --git a/package.json b/package.json
index 93e121a3b2..4492c9607f 100644
--- a/package.json
+++ b/package.json
@@ -35,7 +35,8 @@
 		"build": "yarn run clean && build --win --mac --linux",
 		"build:mac": "yarn run clean && build --mac",
 		"build:win": "yarn run clean && build --win",
-		"plugins": "yarn run plugin:autoconfirm",
+		"plugins": "yarn run plugin:adblocker && yarn run plugin:autoconfirm",
+		"plugin:adblocker": "rimraf plugins/adblocker/ad-blocker-engine.bin && node plugins/adblocker/blocker.js",
 		"plugin:autoconfirm": "yarn run generate:package YoutubeNonStop",
 		"release:linux": "yarn run clean && build --linux -p always",
 		"release:mac": "yarn run clean && build --mac -p always",
diff --git a/plugins/adblocker/.gitignore b/plugins/adblocker/.gitignore
new file mode 100644
index 0000000000..af053a2be1
--- /dev/null
+++ b/plugins/adblocker/.gitignore
@@ -0,0 +1 @@
+/ad-blocker-engine.bin
diff --git a/plugins/adblocker/back.js b/plugins/adblocker/back.js
index 99ee613ff5..caf0cc9758 100644
--- a/plugins/adblocker/back.js
+++ b/plugins/adblocker/back.js
@@ -1,12 +1,2 @@
-const { ElectronBlocker } = require("@cliqz/adblocker-electron");
-const { session } = require("electron");
-const fetch = require("node-fetch");
-
-const SOURCES = [
-	"https://raw.githubusercontent.com/kbinani/adblock-youtube-ads/master/signed.txt"
-];
-
-module.exports = () =>
-	ElectronBlocker.fromLists(fetch, SOURCES)
-		.then(blocker => blocker.enableBlockingInSession(session.defaultSession))
-		.catch(err => console.log("Error loading adBlocker", err));
+const { loadAdBlockerEngine } = require("./blocker");
+module.exports = () => loadAdBlockerEngine(true);
diff --git a/plugins/adblocker/blocker.js b/plugins/adblocker/blocker.js
new file mode 100644
index 0000000000..452924f59c
--- /dev/null
+++ b/plugins/adblocker/blocker.js
@@ -0,0 +1,33 @@
+const { promises } = require("fs"); // used for caching
+const path = require("path");
+
+const { ElectronBlocker } = require("@cliqz/adblocker-electron");
+const { session } = require("electron");
+const fetch = require("node-fetch");
+
+const SOURCES = [
+	"https://raw.githubusercontent.com/kbinani/adblock-youtube-ads/master/signed.txt"
+];
+
+const loadAdBlockerEngine = (enableBlocking = false) =>
+	ElectronBlocker.fromLists(
+		fetch,
+		SOURCES,
+		{},
+		{
+			path: path.resolve(__dirname, "ad-blocker-engine.bin"),
+			read: promises.readFile,
+			write: promises.writeFile
+		}
+	)
+		.then(blocker => {
+			if (enableBlocking) {
+				blocker.enableBlockingInSession(session.defaultSession);
+			}
+		})
+		.catch(err => console.log("Error loading adBlocker engine", err));
+
+module.exports = { loadAdBlockerEngine };
+if (require.main === module) {
+	loadAdBlockerEngine(false); // Generate the engine without enabling it
+}