split py into modules

lektor_groupby/pruner.py

@@ -0,0 +1,39 @@
+'''
+Static collector for build-artifact urls.
+All non-tracked VPATH-urls will be pruned after build.
+'''
+from lektor.builder import Builder  # typing
+from lektor.reporter import reporter  # report_pruned_artifact
+from lektor.utils import prune_file_and_folder
+
+_cache = set()
+# Note: this var is static or otherwise two instances of
+#       this module would prune each others artifacts.
+
+
+def track_not_prune(url: str) -> None:
+    ''' Add url to build cache to prevent pruning. '''
+    _cache.add(url.lstrip('/'))
+
+
+def prune(builder: Builder, vpath: str) -> None:
+    ''' Remove previously generated, unreferenced Artifacts. '''
+    vpath = '@' + vpath.lstrip('@')  # just in case of user error
+    dest_path = builder.destination_path
+    con = builder.connect_to_database()
+    try:
+        with builder.new_build_state() as build_state:
+            for url, file in build_state.iter_artifacts():
+                if url.lstrip('/') in _cache:
+                    continue  # generated in this build-run
+                infos = build_state.get_artifact_dependency_infos(url, [])
+                for artifact_name, _ in infos:
+                    if vpath not in artifact_name:
+                        continue  # we only care about our Virtuals
+                    reporter.report_pruned_artifact(url)
+                    prune_file_and_folder(file.filename, dest_path)
+                    build_state.remove_artifact(url)
+                    break  # there is only one VPATH-entry per source
+    finally:
+        con.close()
+    _cache.clear()