Issue 5535 - Replace our module system with webpack

webpack_runner.js

Index: webpack_runner.js
diff --git a/webpack_runner.js b/webpack_runner.js
new file mode 100644
index 0000000000000000000000000000000000000000..04ecad8cc25b092bccfb8814078127138118fd5b
--- /dev/null
+++ b/webpack_runner.js
@@ -0,0 +1,130 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+const path = require("path");
+const process = require("process");
+
+const MemoryFS = require("memory-fs");
+const webpack = require("webpack");
+
+let {BOUNDARY, BUNDLES, EXTENSION_PATH,
+     RESOLVE_PATHS} = JSON.parse(process.argv[2]);
+
+// Since the cost of starting Node.js and loading all the modules is hugely
+// larger than actually producing bundles we avoid paying it multiple times.
+// To acheive this we output all the required bundles - along with their

[Wladimir Palant, 2017/10/09 10:54:55]

Typo: achieve

[kzar, 2017/10/09 13:52:15]

Done.

+// names - in one go.
+let options = [];
+for (let {BUNDLE_NAME, ENTRY_POINTS} of BUNDLES)
+{
+  options.push({
+    context: EXTENSION_PATH,
+    devtool: "source-map",
+    module: {
+      rules: [{
+        include: path.join(EXTENSION_PATH, "lib", "info.js"),
+        use: ["info-loader"]
+      }]
+    },
+    entry: ENTRY_POINTS,
+    output: {
+      path: "/",
+      filename: BUNDLE_NAME
+    },
+    resolve: {
+      modules: RESOLVE_PATHS,
+      alias: {
+        // Prevent builtin Node.js modules from being used instead of our own
+        // when the names clash. Once relative paths are used this won't be
+        // necessary.
+        url$: "url.js",
+        events$: "events.js",
+        punycode$: "punycode.js"
+      },
+      plugins: [
+        function()
+        {
+          // Our old module system in packagerChrome.py used to prefix
+          // module names with the name of their parent directory and an
+          // underscore - but only when that directory wasn't called
+          // "lib". This plugin is for backwards compatability, but can
+          // be removed once use of that deprecated syntax has been
+          // replaced.
+          this.plugin("described-resolve", (request, callback) =>
+          {
+            let target = request.request;
+
+            let prefix_index = target.indexOf("_");
+            if (prefix_index == -1)
+              return callback();
+
+            let prefix = target.substring(0, prefix_index);
+            if (prefix == "lib")
+              return callback();
+
+            let fixed_target = path.join(prefix,
+                                         target.substring(prefix_index + 1));
+            return this.doResolve(
+              "resolve", Object.assign({}, request, {request: fixed_target}),
+              "Changed prefixed path using legacy buildtools syntax from " +
+              target + " to " + fixed_target,
+              callback
+            );
+          });
+        }
+      ]
+    },
+    resolveLoader: {
+      modules: [path.resolve(__dirname)]
+    }
+  });
+}
+
+// Based on this example
+// https://webpack.js.org/api/node/#custom-file-systems
+let memoryFS = new MemoryFS();
+let webpackCompiler = webpack(options);
+
+webpackCompiler.outputFileSystem = memoryFS;
+webpackCompiler.run((err, stats) =>
+{
+  // Error handling is based on this example
+  // https://webpack.js.org/api/node/#error-handling
+  if (err)
+  {
+    let reason = err.stack || err;
+    if (err.details)
+      reason += "\n" + err.details;
+    throw new Error(reason);
+  }
+  else if (stats.hasErrors())
+    throw new Error(stats.toJson().errors.join("\n"));
+  else
+  {
+    for (let config of options)
+    {
+      let filepath = path.join(config.output.path, config.output.filename);
+      let mappath = filepath + ".map";
+      console.log(filepath, BOUNDARY,
+                  memoryFS.readFileSync(filepath, "utf-8"), BOUNDARY,
+                  mappath, BOUNDARY,
+                  memoryFS.readFileSync(mappath, "utf-8"), BOUNDARY);

[Wladimir Palant, 2017/10/09 10:54:56]

How about printing JSON instead of this boundary hack?

[kzar, 2017/10/09 13:52:15]

Done.

+      memoryFS.unlinkSync(filepath);
+      memoryFS.unlinkSync(mappath);
+    }
+  }
+});