Move the ClearDocuments update into its own module

src/update/clear_documents.rs

@@ -0,0 +1,49 @@
+use roaring::RoaringBitmap;
+use crate::Index;
+
+pub struct ClearDocuments<'t, 'u, 'i> {
+    wtxn: &'t mut heed::RwTxn<'u>,
+    index: &'i Index,
+}
+
+impl<'t, 'u, 'i> ClearDocuments<'t, 'u, 'i> {
+    pub fn new(wtxn: &'t mut heed::RwTxn<'u>, index: &'i Index) -> ClearDocuments<'t, 'u, 'i> {
+        ClearDocuments { wtxn, index }
+    }
+
+    pub fn execute(self) -> anyhow::Result<usize> {
+        let Index {
+            main: _main,
+            word_docids,
+            docid_word_positions,
+            word_pair_proximity_docids,
+            documents,
+        } = self.index;
+
+        // We clear the word fst.
+        self.index.put_words_fst(self.wtxn, &fst::Set::default())?;
+
+        // We clear the users ids documents ids.
+        self.index.put_users_ids_documents_ids(self.wtxn, &fst::Map::default())?;
+
+        // We retrieve the documents ids.
+        let documents_ids = self.index.documents_ids(self.wtxn)?;
+
+        // We clear the internal documents ids.
+        self.index.put_documents_ids(self.wtxn, &RoaringBitmap::default())?;
+
+        // We clear the word docids.
+        word_docids.clear(self.wtxn)?;
+
+        // We clear the docid word positions.
+        docid_word_positions.clear(self.wtxn)?;
+
+        // We clear the word pair proximity docids.
+        word_pair_proximity_docids.clear(self.wtxn)?;
+
+        // We clear the documents themselves.
+        documents.clear(self.wtxn)?;
+
+        Ok(documents_ids.len() as usize)
+    }
+}