🐲 GN(android) Don't run find.py on build/android/ant/empty/res

build/config/android/internal_rules.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/zip.gni")
 import("//third_party/ijar/ijar.gni")
 
 assert(is_android)
@@ skipping 1809 matching lines @@
       zip_path,
       srcjar_path,
       r_text_path,
     ]
 
     _all_resource_dirs = []
     sources = []
 
     if (defined(invoker.resource_dirs)) {
       _all_resource_dirs += invoker.resource_dirs
-      sources_build_rel =
-          exec_script("//build/android/gyp/find.py",
-                      rebase_path(invoker.resource_dirs, root_build_dir),
-                      "list lines")
-      sources += rebase_path(sources_build_rel, ".", root_build_dir)
+
+      # Speed up "gn gen" by short-circuiting the empty directory.
+      if (invoker.resource_dirs != [ "//build/android/ant/empty/res" ] &&
+          invoker.resource_dirs != []) {
+        _sources_build_rel =
+            exec_script("//build/android/gyp/find.py",
+                        rebase_path(invoker.resource_dirs, root_build_dir),
+                        "list lines")
+        sources += rebase_path(_sources_build_rel, ".", root_build_dir)
+      }
     }
 
     if (defined(invoker.generated_resource_dirs)) {
       assert(defined(invoker.generated_resource_files))
       _all_resource_dirs += invoker.generated_resource_dirs
       sources += invoker.generated_resource_files
     }
 
     inputs = [
       build_config,
@@ skipping 370 matching lines @@
 
     args = [
       "--depfile",
       rebase_path(depfile, root_build_dir),
       "--script-output-path",
       rebase_path(generated_script, root_build_dir),
     ]
     args += test_runner_args
   }
 }