feat: add allocation-free scalar path visitors

Cargo.toml

@@ -41,14 +41,14 @@ serde_json = { version = "1.0", default-features = false, features = ["std"] }
 zmij = "1.0"
 
 [dev-dependencies]
+criterion = "0.5.1"
 goldenfile = "1.8"
-serde_json = "1.0"
 json-deserializer = "0.4.4"
-simd-json = "0.15.0"
+json-five = "0.3.0"
 mockalloc = "0.1.2"
-criterion = "0.5.1"
 proptest = "1.7"
-json-five = "0.3.0"
+serde_json = "1.0"
+simd-json = "0.15.0"
 
 [features]
 default = ["databend", "preserve_order", "arbitrary_precision"]

benches/strip_nulls.rs

@@ -40,7 +40,7 @@ fn strip_value_nulls(val: &mut Value<'_>) {
             }
         }
         Value::Object(ref mut obj) => {
-            for (_, v) in obj.iter_mut() {
+            for v in obj.values_mut() {
                 strip_value_nulls(v);
             }
             obj.retain(|_, v| !matches!(v, Value::Null));

src/core/databend/ser.rs

@@ -1031,7 +1031,7 @@ impl<'a> Encoder<'a> {
         let (mut object_len, mut jentry_index) = self.base_encoder.encode_object_header(obj.len());
 
         // encode all keys first
-        for (key, _) in obj.iter() {
+        for key in obj.keys() {
             let len = key.len();
             object_len += len;
             self.base_encoder.buf.extend_from_slice(key.as_bytes());
@@ -1040,7 +1040,7 @@ impl<'a> Encoder<'a> {
         }
 
         // encode all values
-        for (_, value) in obj.iter() {
+        for value in obj.values() {
             let jentry = self.encode_value(value);
             object_len += jentry.length as usize;
             self.base_encoder.replace_jentry(jentry, &mut jentry_index);