Add more commands

* exists
* decrby
* mget

src/cmd/key.rs

@@ -16,6 +16,10 @@ pub fn del(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     Ok(conn.db().del(&args[1..]))
 }
 
+pub fn exists(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
+    Ok(conn.db().exists(&args[1..]))
+}
+
 pub fn expire(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     let expires_in: i64 = bytes_to_number(&args[2])?;
 
@@ -30,7 +34,7 @@ pub fn expire(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
         Duration::from_millis(expires_in as u64)
     };
 
-    Ok(conn.db().expire(&args[1], expires_at))
+    Ok(conn.db().add_expiration(&args[1], expires_at))
 }
 
 pub fn expire_at(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
@@ -53,7 +57,7 @@ pub fn expire_at(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
         Duration::from_millis(expires_in as u64)
     };
 
-    Ok(conn.db().expire(&args[1], expires_at))
+    Ok(conn.db().add_expiration(&args[1], expires_at))
 }
 
 pub fn ttl(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
@@ -93,5 +97,5 @@ pub fn expire_time(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
 }
 
 pub fn persist(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
-    Ok(conn.db().persist(&args[1]))
+    Ok(conn.db().remove_expiration(&args[1]))
 }

src/cmd/string.rs

@@ -15,6 +15,11 @@ pub fn decr(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     conn.db().incr(&args[1], -1)
 }
 
+pub fn decr_by(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
+    let by: i64 = (&Value::Blob(args[2].to_owned())).try_into()?;
+    conn.db().incr(&args[1], -1 * by)
+}
+
 pub fn get(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     Ok(conn.db().get(&args[1]))
 }
@@ -23,6 +28,11 @@ pub fn getdel(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     Ok(conn.db().getdel(&args[1]))
 }
 
+pub fn mget(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
+    Ok(conn.db().get_multi(&args[1..]))
+}
+
+
 pub fn set(conn: &Connection, args: &[Bytes]) -> Result<Value, Error> {
     Ok(conn.db().set(&args[1], &Value::Blob(args[2].to_owned())))
 }

src/db/mod.rs

@@ -77,7 +77,7 @@ impl Db {
         }
     }
 
-    pub fn persist(&self, key: &Bytes) -> Value {
+    pub fn remove_expiration(&self, key: &Bytes) -> Value {
         let mut entries = self.entries[self.get_slot(key)].write().unwrap();
         entries
             .get_mut(key)
@@ -89,7 +89,7 @@ impl Db {
             })
     }
 
-    pub fn expire(&self, key: &Bytes, time: Duration) -> Value {
+    pub fn add_expiration(&self, key: &Bytes, time: Duration) -> Value {
         let mut entries = self.entries[self.get_slot(key)].write().unwrap();
         entries
             .get_mut(key)
@@ -114,6 +114,20 @@ impl Db {
         deleted.into()
     }
 
+    pub fn exists(&self, keys: &[Bytes]) -> Value {
+        let mut matches = 0_i64;
+        keys.iter()
+            .map(|key| {
+                let entries = self.entries[self.get_slot(key)].read().unwrap();
+                if entries.get(key).is_some() {
+                    matches += 1;
+                }
+            })
+            .for_each(drop);
+
+        matches.into()
+    }
+
     pub fn get(&self, key: &Bytes) -> Value {
         let entries = self.entries[self.get_slot(key)].read().unwrap();
         entries
@@ -122,6 +136,15 @@ impl Db {
             .map_or(Value::Null, |x| x.get().clone())
     }
 
+    pub fn get_multi(&self, keys: &[Bytes]) -> Value {
+        keys.iter()
+            .map(|key| {
+                let entries = self.entries[self.get_slot(key)].read().unwrap();
+                entries.get(key)
+                    .map_or(Value::Null, |x| x.get().clone())
+            }).collect::<Vec<Value>>().into()
+    }
+
     pub fn getset(&self, key: &Bytes, value: &Value) -> Value {
         let mut entries = self.entries[self.get_slot(key)].write().unwrap();
         entries

src/dispatcher.rs

@@ -28,6 +28,11 @@ dispatcher! {
             ["random" "loading" "stale"],
             -2,
         },
+        exists {
+            cmd::key::exists,
+            ["read" "fast"],
+            -2,
+        },
         expire {
             cmd::key::expire,
             ["read" "write" "fast"],
@@ -80,6 +85,11 @@ dispatcher! {
             ["write" "denyoom" "fast"],
             2,
         },
+        decrby {
+            cmd::string::decr_by,
+            ["write" "denyoom" "fast"],
+            3,
+        },
         get {
             cmd::string::get,
             ["random" "loading" "stale"],
@@ -105,6 +115,11 @@ dispatcher! {
             ["write" "denyoom" "fast"],
             3,
         },
+        mget {
+            cmd::string::mget,
+            ["random" "loading" "stale"],
+            -2,
+        },
         set {
             cmd::string::set,
             ["random" "loading" "stale"],

src/value.rs

@@ -108,3 +108,9 @@ impl From<String> for Value {
         value.as_str().into()
     }
 }
+
+impl From<Vec<Value>> for Value {
+    fn from(value: Vec<Value>) -> Value {
+        Value::Array(value)
+    }
+}