feat: Simplify the steps to query the database

src/database/database_view.rs

@@ -7,7 +7,9 @@ use serde::de::DeserializeOwned;
 
 use crate::database::{retrieve_data_schema, DocumentKey, DocumentKeyAttr};
 use crate::database::deserializer::Deserializer;
+use crate::rank::criterion::Criterion;
 use crate::database::schema::Schema;
+use crate::rank::QueryBuilder;
 use crate::DocumentId;
 
 pub struct DatabaseView<'a> {
@@ -21,14 +23,26 @@ impl<'a> DatabaseView<'a> {
         Ok(DatabaseView { snapshot, schema })
     }
 
+    pub fn schema(&self) -> &Schema {
+        &self.schema
+    }
+
     pub fn into_snapshot(self) -> Snapshot<&'a DB> {
         self.snapshot
     }
 
+    pub fn snapshot(&self) -> &Snapshot<&'a DB> {
+        &self.snapshot
+    }
+
     pub fn get(&self, key: &[u8]) -> Result<Option<DBVector>, Box<Error>> {
         Ok(self.snapshot.get(key)?)
     }
 
+    pub fn query_builder(&self) -> Result<QueryBuilder<Box<dyn Criterion>>, Box<Error>> {
+        QueryBuilder::new(self)
+    }
+
     // TODO create an enum error type
     pub fn retrieve_document<D>(&self, id: DocumentId) -> Result<D, Box<Error>>
     where D: DeserializeOwned

src/database/mod.rs

@@ -8,7 +8,7 @@ use rocksdb::{DB, DBVector, MergeOperands, SeekKey};
 use rocksdb::rocksdb::{Writable, Snapshot};
 
 pub use self::document_key::{DocumentKey, DocumentKeyAttr};
-pub use self::database_view::DatabaseView;
+pub use self::database_view::{DatabaseView, DocumentIter};
 use self::blob::positive::PositiveBlob;
 use self::update::Update;
 use self::schema::Schema;
@@ -126,7 +126,7 @@ impl fmt::Debug for Database {
         let mut iter = self.0.iter();
         iter.seek(SeekKey::Start);
         let mut first = true;
-        for (key, value) in &mut iter {
+        for (key, _value) in &mut iter {
             if !first { write!(f, ", ")?; }
             first = false;
             let key = String::from_utf8_lossy(&key);

src/database/update/positive/unordered_builder.rs

@@ -1,3 +1,5 @@
+#![allow(unused)]
+
 use std::collections::BTreeMap;
 use std::error::Error;
 use std::io::Write;

src/database/update/positive/update.rs

@@ -107,7 +107,7 @@ struct Serializer<'a, B> {
 macro_rules! forward_to_unserializable_type {
     ($($ty:ident => $se_method:ident,)*) => {
         $(
-            fn $se_method(self, v: $ty) -> Result<Self::Ok, Self::Error> {
+            fn $se_method(self, _v: $ty) -> Result<Self::Ok, Self::Error> {
                 Err(SerializerError::UnserializableType { name: "$ty" })
             }
         )*
@@ -145,11 +145,11 @@ where B: TokenizerBuilder
         f64 => serialize_f64,
     }
 
-    fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
+    fn serialize_str(self, _v: &str) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "str" })
     }
 
-    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "&[u8]" })
     }
 
@@ -375,7 +375,7 @@ where B: TokenizerBuilder
         Ok(())
     }
 
-    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
         Err(SerializerError::UnserializableType { name: "&[u8]" })
     }