add installer to build package

src/paths.js

@@ -3,10 +3,36 @@
 const path = require('path')
 const fs = require('fs')
 
-const APP_ROOT = path.resolve(__dirname, '..')
+// Packaged builds run from <portable root>/electron/resources/app.asar:
+// the portable layout (<root>/files) is two levels above the resources dir
+// and files bundled with the release are unpacked next to the asar.
+function computeRoots() {
+  const m = __dirname.match(/^(.*)[/\\]app\.asar([/\\]|$)/)
+  if (m) {
+    const RESOURCES = path.resolve(m[1])
+    const APP_ROOT = path.resolve(RESOURCES, '..', '..')
+    return {
+      RESOURCES,
+      APP_ROOT,
+      // FILES = BUILD/files, so BUILD is the portable root itself.
+      BUILD: process.env.PLWL_BUILD_DIR || APP_ROOT,
+      // Bundled release files live inside the asar (Electron's patched fs
+      // can read them directly from the archive).
+      BUNDLED: fs.existsSync(path.join(RESOURCES, 'app.asar', 'files', 'translations'))
+        ? path.join(RESOURCES, 'app.asar', 'files')
+        : path.join(APP_ROOT, 'files')
+    }
+  }
+  const APP_ROOT = path.resolve(__dirname, '..')
+  return {
+    RESOURCES: APP_ROOT,
+    APP_ROOT,
+    BUILD: process.env.PLWL_BUILD_DIR || path.join(APP_ROOT, 'build'),
+    BUNDLED: path.join(APP_ROOT, 'files')
+  }
+}
 
-const BUILD = process.env.PLWL_BUILD_DIR || path.join(APP_ROOT, 'build')
-const BUNDLED = path.join(APP_ROOT, 'files')
+const { RESOURCES, APP_ROOT, BUILD, BUNDLED } = computeRoots()
 
 const FILES = path.join(BUILD, 'files')
 const DATA = path.join(FILES, 'data')
@@ -53,4 +79,4 @@ function writeJson(file, data) {
   fs.renameSync(tmp, file)
 }
 
-module.exports = { APP_ROOT, BUILD, FILES, DATA, DIRS, ensureDirs, readJson, writeJson }
+module.exports = { RESOURCES, APP_ROOT, BUILD, FILES, DATA, DIRS, ensureDirs, readJson, writeJson }