1 files changed, 85 insertions, 0 deletions
diff --git a/nikola/plugins/task_create_bundles.py b/nikola/plugins/task_create_bundles.py
new file mode 100644
index 0000000..ebca0b7
--- /dev/null
+++ b/nikola/plugins/task_create_bundles.py
@@ -0,0 +1,85 @@
+import os
+
+try:
+    import webassets
+except ImportError:
+    webassets = None  # NOQA
+
+from nikola.plugin_categories import LateTask
+from nikola import utils
+
+
+class BuildBundles(LateTask):
+    """Bundle assets using WebAssets."""
+
+    name = "build_bundles"
+
+    def set_site(self, site):
+        super(BuildBundles, self).set_site(site)
+        if webassets is None:
+            self.site.config['USE_BUNDLES'] = False
+
+    def gen_tasks(self):
+        """Bundle assets using WebAssets."""
+
+        kw = {
+            'filters': self.site.config['FILTERS'],
+            'output_folder': self.site.config['OUTPUT_FOLDER'],
+            'theme_bundles': get_theme_bundles(self.site.THEMES),
+        }
+
+        def build_bundle(output, inputs):
+            out_dir = os.path.join(kw['output_folder'], os.path.dirname(output))
+            inputs = [i for i in inputs if os.path.isfile(
+                os.path.join(out_dir, i))]
+            cache_dir = os.path.join('cache', 'webassets')
+            if not os.path.isdir(cache_dir):
+                os.makedirs(cache_dir)
+            env = webassets.Environment(out_dir, os.path.dirname(output),
+                cache=cache_dir)
+            bundle = webassets.Bundle(*inputs,
+                output=os.path.basename(output))
+            env.register(output, bundle)
+            # This generates the file
+            env[output].urls()
+
+        flag = False
+        if webassets is not None and self.site.config['USE_BUNDLES'] is not False:
+            for name, files in kw['theme_bundles'].items():
+                output_path = os.path.join(kw['output_folder'], name)
+                dname = os.path.dirname(name)
+                file_dep = [os.path.join('output', dname, fname)
+                    for fname in files]
+                task = {
+                    'file_dep': file_dep,
+                    'basename': self.name,
+                    'name': output_path,
+                    'actions': [(build_bundle, (name, files))],
+                    'targets': [output_path],
+                    'uptodate': [utils.config_changed(kw)]
+                    }
+                flag = True
+                yield utils.apply_filters(task, kw['filters'])
+        if flag is False:  # No page rendered, yield a dummy task
+            yield {
+                'basename': self.name,
+                'uptodate': [True],
+                'name': 'None',
+                'actions': [],
+            }
+
+
+def get_theme_bundles(themes):
+    """Given a theme chain, return the bundle definitions."""
+    bundles = {}
+    for theme_name in themes:
+        bundles_path = os.path.join(
+            utils.get_theme_path(theme_name), 'bundles')
+        if os.path.isfile(bundles_path):
+            with open(bundles_path) as fd:
+                for line in fd:
+                    name, files = line.split('=')
+                    files = [f.strip() for f in files.split(',')]
+                    bundles[name.strip()] = files
+                break
+    return bundles