feature: support get/set, hget/hset/hgetall command

Cargo.toml

@@ -8,5 +8,7 @@ edition = "2021"
 [dependencies]
 anyhow = "1.0.81"
 bytes = "1.6.0"
+dashmap = "5.5.3"
 enum_dispatch = "0.3.13"
+lazy_static = "1.4.0"
 thiserror = "1.0.58"

src/backend/mod.rs

@@ -0,0 +1,65 @@
+use crate::RespFrame;
+use dashmap::DashMap;
+use std::ops::Deref;
+use std::sync::Arc;
+
+#[derive(Debug, Clone)]
+pub struct Backend(Arc<BackendInner>);
+
+#[derive(Debug)]
+pub struct BackendInner {
+    pub(crate) map: DashMap<String, RespFrame>,
+    pub(crate) hmap: DashMap<String, DashMap<String, RespFrame>>,
+}
+
+impl Deref for Backend {
+    type Target = BackendInner;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Default for Backend {
+    fn default() -> Self {
+        Self(Arc::new(BackendInner::default()))
+    }
+}
+
+impl Default for BackendInner {
+    fn default() -> Self {
+        Self {
+            map: DashMap::new(),
+            hmap: DashMap::new(),
+        }
+    }
+}
+
+impl Backend {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn get(&self, key: &str) -> Option<RespFrame> {
+        self.map.get(key).map(|v| v.value().clone())
+    }
+
+    pub fn set(&self, key: String, value: RespFrame) {
+        self.map.insert(key, value);
+    }
+
+    pub fn hget(&self, key: &str, field: &str) -> Option<RespFrame> {
+        self.hmap
+            .get(key)
+            .and_then(|v| v.get(field).map(|v| v.value().clone()))
+    }
+
+    pub fn hset(&self, key: String, field: String, value: RespFrame) {
+        let hmap = self.hmap.entry(key).or_default();
+        hmap.insert(field, value);
+    }
+
+    pub fn hgetall(&self, key: &str) -> Option<DashMap<String, RespFrame>> {
+        self.hmap.get(key).map(|v| v.clone())
+    }
+}