feat: Use DIR_ASSETS path to locate resource bundles (#47950)

* feat: Use DIR_ASSETS path to locate resource bundles

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* Use DIR_ASSETS for calculating ASAR relative paths

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* Add test to verify 'assets' matches parent dir of 'exe'

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* Add Mac-specific test for assets path (but it is failing)

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* test: Update app.getPath('assets') to expect an exception on Mac

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* docs: Update docs for 'assets' path to indicate that it's only available on Windows + Linux

Co-authored-by: Will Anderson <andersonw@dropbox.com>

* fix: Don't define 'assets' mapping on macOS

Co-authored-by: Will Anderson <andersonw@dropbox.com>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Will Anderson <andersonw@dropbox.com>

docs/api/app.md

@@ -602,6 +602,7 @@ Returns `string` - The current application directory.
     * `%APPDATA%` on Windows
     * `$XDG_CONFIG_HOME` or `~/.config` on Linux
     * `~/Library/Application Support` on macOS
+  * `assets` The directory where app assets such as `resources.pak` are stored. By default this is the same as the folder containing the `exe` path. Available on Windows and Linux only.
   * `userData` The directory for storing your app's configuration files, which
     by default is the `appData` directory appended with your app's name. By
     convention files storing user data should be written to this directory, and
@@ -616,7 +617,7 @@ Returns `string` - The current application directory.
     directory.
   * `temp` Temporary directory.
   * `exe` The current executable file.
-  * `module` The `libchromiumcontent` library.
+  * `module` The location of the Chromium module. By default this is synonymous with `exe`.
   * `desktop` The current user's Desktop directory.
   * `documents` Directory for a user's "My Documents".
   * `downloads` Directory for a user's downloads.

shell/app/electron_main_delegate.cc

@@ -219,7 +219,7 @@ std::string LoadResourceBundle(const std::string& locale) {
   pak_dir =
       base::apple::FrameworkBundlePath().Append(FILE_PATH_LITERAL("Resources"));
 #else
-  base::PathService::Get(base::DIR_MODULE, &pak_dir);
+  base::PathService::Get(base::DIR_ASSETS, &pak_dir);
 #endif
 
   std::string loaded_locale = ui::ResourceBundle::InitSharedInstanceWithLocale(

shell/browser/api/electron_api_app.cc

@@ -383,6 +383,9 @@ int GetPathConstant(std::string_view name) {
   // clang-format off
   constexpr auto Lookup = base::MakeFixedFlatMap<std::string_view, int>({
       {"appData", DIR_APP_DATA},
+#if !BUILDFLAG(IS_MAC)
+      {"assets", base::DIR_ASSETS},
+#endif
 #if BUILDFLAG(IS_POSIX)
       {"cache", base::DIR_CACHE},
 #else

shell/common/asar/archive_win.cc

@@ -26,13 +26,13 @@ const wchar_t kIntegrityCheckResourceType[] = L"Integrity";
 const wchar_t kIntegrityCheckResourceItem[] = L"ElectronAsar";
 
 std::optional<base::FilePath> Archive::RelativePath() const {
-  base::FilePath exe_path;
+  base::FilePath assets_dir;
-  if (!base::PathService::Get(base::FILE_EXE, &exe_path)) {
+  if (!base::PathService::Get(base::DIR_ASSETS, &assets_dir)) {
-    LOG(FATAL) << "Couldn't get exe file path";
+    LOG(FATAL) << "Couldn't get assets directory path";
   }
 
   base::FilePath relative_path;
-  if (!exe_path.DirName().AppendRelativePath(path_, &relative_path)) {
+  if (!assets_dir.AppendRelativePath(path_, &relative_path)) {
     return std::nullopt;
   }
 

shell/common/node_bindings.cc

@@ -456,11 +456,10 @@ base::FilePath GetResourcesPath() {
 #if BUILDFLAG(IS_MAC)
   return MainApplicationBundlePath().Append("Contents").Append("Resources");
 #else
-  auto* command_line = base::CommandLine::ForCurrentProcess();
+  base::FilePath assets_path;
-  base::FilePath exec_path(command_line->GetProgram());
+  base::PathService::Get(base::DIR_ASSETS, &assets_path);
-  base::PathService::Get(base::FILE_EXE, &exec_path);
 
-  return exec_path.DirName().Append(FILE_PATH_LITERAL("resources"));
+  return assets_path.Append(FILE_PATH_LITERAL("resources"));
 #endif
 }
 }  // namespace

spec/api-app-spec.ts

@@ -1109,6 +1109,20 @@ describe('app module', () => {
       expect(paths).to.deep.equal([true, true, true]);
     });
 
+    if (process.platform === 'darwin') {
+      it('throws an error when trying to get the assets path on macOS', () => {
+        expect(() => {
+          app.getPath('assets' as any);
+        }).to.throw(/Failed to get 'assets' path/);
+      });
+    } else {
+      it('returns an assets path that is identical to the module path', () => {
+        const assetsPath = app.getPath('assets');
+        expect(fs.existsSync(assetsPath)).to.be.true();
+        expect(assetsPath).to.equal(path.dirname(app.getPath('module')));
+      });
+    }
+
     it('throws an error when the name is invalid', () => {
       expect(() => {
         app.getPath('does-not-exist' as any);