[gnome-shell-extensions] classic: Pre-generate stylesheet

[Marge Bot <marge-bot src gnome org>]

commit 669e7c32a2cbc87b2818490beae0a2e25e799845
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Dec 29 00:18:47 2020 +0100

    classic: Pre-generate stylesheet
    
    We follow the rule of not putting generated files under version
    control, but that means drawing in additional build-time dependencies.
    We can reduce those when building from a released tarball by
    generating the stylesheets at dist time though, so do that.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/150>

 data/meson.build              | 23 ++++++++++++++---------
 meson.build                   |  4 +++-
 meson/generate-stylesheets.py | 13 +++++++++++++
 3 files changed, 30 insertions(+), 10 deletions(-)
---
diff --git a/data/meson.build b/data/meson.build
index 4a02931..27f4287 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -76,15 +76,20 @@ theme_data = [
   'gnome-classic-high-contrast.css'
 ]
 
-style = 'gnome-classic'
-custom_target(style + '.css',
-  input: style + '.scss',
-  output: style + '.css',
-  depend_files: theme_sources,
-  command: [sassc, '-a', '@INPUT@', '@OUTPUT@'],
-  install: true,
-  install_dir: themedir
-)
+stylesheet = 'gnome-classic.css'
+if fs.exists(stylesheet)
+  install_data(stylesheet, install_dir: themedir)
+else
+  sassc = find_program('sassc', required: true)
+  custom_target(stylesheet,
+    input: fs.replace_suffix(stylesheet, '.scss'),
+    output: stylesheet,
+    depend_files: theme_sources,
+    command: [sassc, '-a', '@INPUT@', '@OUTPUT@'],
+    install: true,
+    install_dir: themedir
+  )
+endif
 
 install_data(theme_data, install_dir: themedir)
 
diff --git a/meson.build b/meson.build
index 9e99d74..f1a4108 100644
--- a/meson.build
+++ b/meson.build
@@ -6,6 +6,7 @@ project('gnome-shell-extensions',
 
 gettext_domain = meson.project_name()
 
+fs = import('fs')
 gnome = import('gnome')
 i18n = import('i18n')
 
@@ -86,9 +87,10 @@ foreach e : enabled_extensions
 endforeach
 
 if classic_mode_enabled
-  sassc = find_program('sassc', required: true)
   subdir('data')
 endif
 
 subdir('extensions')
 subdir('po')
+
+meson.add_dist_script('meson/generate-stylesheets.py')
diff --git a/meson/generate-stylesheets.py b/meson/generate-stylesheets.py
new file mode 100644
index 0000000..6e402b6
--- /dev/null
+++ b/meson/generate-stylesheets.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+import os
+from pathlib import PurePath
+import subprocess
+
+sourceroot = os.environ.get('MESON_SOURCE_ROOT')
+distroot = os.environ.get('MESON_DIST_ROOT')
+
+stylesheet_path = PurePath('data/gnome-classic.css')
+src = PurePath(sourceroot, stylesheet_path.with_suffix('.scss'))
+dst = PurePath(distroot, stylesheet_path)
+subprocess.call(['sassc', '-a', src, dst])