Add indexing to deletion

storage_engine/src/cursor.rs

@@ -400,7 +400,6 @@ pub trait CursorWithWriteAccessToIndex<T>: CursorWithAccessToIndex<T> + CursorWi
     }
         
     async fn insert_entry(&mut self, entry: Entry<T>) -> Result<FilePosition> 
-        // TODO: Why is 'async_trait necessary?
         where T: Encode + Decode + Ord + Send + Sync + 'async_trait
     {
         let file_position = self.append_entry_no_indexing(&entry).await?;
@@ -415,6 +414,18 @@ pub trait CursorWithWriteAccessToIndex<T>: CursorWithAccessToIndex<T> + CursorWi
 
         Ok(file_position)
     }
+
+    async fn delete_entry_values_from_indexes(&mut self, entry: EntryDetailed<T>) -> Result<()>
+        where T: Encode + Decode + Ord + Send + Sync + 'async_trait
+    {
+        for (column, (value, should_index)) in entry.data.into_iter().zip(self.header().indexed_columns.clone()).enumerate() {
+            if should_index {
+                // SAFETY: If should_index is true, then the column is indexable.
+                self.delete_from_index(column as Column, value, entry.file_position).await?
+            }
+        }
+        Ok(())
+    }
 }
 
 
@@ -591,26 +602,39 @@ impl <'cursor, T> WriteCursor<'cursor, T>
 
     // ===Deletion===
     pub async fn mark_deleted_at(&mut self, file_position: FilePosition) -> Result<()> 
-        where T: Send + Decode + Encode
+        where T: Encode + Decode + Ord + Send + Sync
     {
         self.seek_to(file_position).await?;
         let mut entry_header = self.read_entry_header().await?;
         if entry_header.is_deleted {
             Ok(())
         } else {
+            // Update store and entry headers
             self.increment_deleted_count().await?;
             self.seek_to(file_position).await?;
 
             entry_header.is_deleted = true;
             self.set_new_entry_header(entry_header.into()).await?;
 
+            // Update index
+            self.seek_to(file_position).await?;
+            match self.next().await? {
+                Some(entry) => {
+                    self.delete_entry_values_from_indexes(entry).await?
+                },
+                None => {
+                    // SAFETY: We just modified its header, so it must exist.
+                    unreachable!()
+                }
+            }
+
             self.attempt_garbage_collection_if_necessary().await?;
             Ok(())
         }
     }
 
     async fn find_first_eq_bruteforce_and_delete(&mut self, column: Column, t0: &T) -> Result<Option<EntryDetailed<T>>> 
-        where T: Decode + Encode + PartialEq + Send + Sync
+        where T: Encode + Decode + Ord + Send + Sync
     {
         let maybe_entry = self.find_first_eq_bruteforce(column, t0).await?;
         if let Some(entry) = maybe_entry {
@@ -621,6 +645,28 @@ impl <'cursor, T> WriteCursor<'cursor, T>
         }
     }
 
+    // ===Indexing===
+    // WARNING: Assumes the column is NOT indexable.
+    pub async fn attach_index(&mut self, column: Column) -> Result<()> 
+        where T: Ord + Decode + Encode + Send + Sync
+    {
+        // New Index
+        let index = Store::create_empty_index_at(&self.header, column).await?;
+        self.indexes[column as usize] = Some(index);
+
+        // Mark column as indexed
+        self.header.make_column_indexed(column);
+        self.set_header(&self.header.clone()).await?;
+
+        // Build index
+        self.seek_to_start_of_data().await?;
+        while let Some((_, file_position, value)) = self.next_alive_at_column(column).await? {
+            self.insert_into_index(column, value, file_position).await?
+        }
+
+        Ok(())
+    }
+
     // ===Garbage Collection===
     async fn attempt_garbage_collection_if_necessary(&mut self) -> Result<()> 
         where T: Send + Decode + Encode
@@ -701,34 +747,5 @@ impl <'cursor, T> WriteCursor<'cursor, T>
 
         Ok(cursor_to_intermediate)
     }
-
-    // ===Indexing===
-    // WARNING: Assumes the column is NOT indexable.
-    pub async fn attach_index(&mut self, column: Column) -> Result<()> 
-        where T: Ord + Decode + Encode + Send + Sync
-    {
-        // New Index
-        let index = Store::create_empty_index_at(&self.header, column).await?;
-        self.indexes[column as usize] = Some(index);
-
-        // Mark column as indexed
-        self.header.make_column_indexed(column);
-        self.set_header(&self.header.clone()).await?;
-
-        // Build index
-        self.seek_to_start_of_data().await?;
-        while let Some((_, file_position, value)) = self.next_alive_at_column(column).await? {
-            self.insert_into_index(column, value, file_position).await?
-        }
-
-        Ok(())
-    }
-
-    async fn delete_from_index(&mut self, t: T, file_position: FilePosition) -> Result<Option<FilePosition>> 
-        where T: Encode + Decode + Ord + Send + Sync
-    {
-        // let x = self.primary_index.delete(t, file_position).await?;
-        todo!()
-    }
 }