expire command

src/client.rs

@@ -170,6 +170,34 @@ impl Client {
         Ok(ttl)
     }
 
+    pub async fn expire(&mut self, key: &str, seconds: u64) -> Result<bool> {
+        let mut bytes = BytesMut::new();
+        bytes.put_u16(6);
+        bytes.put_slice(b"expire");
+
+        let key_length: u16 = key
+            .len()
+            .try_into()
+            .map_err(|_| AppError::KeyLength(key.len()))?;
+
+        bytes.put_u16(key_length);
+        bytes.put_slice(key.as_bytes());
+
+        bytes.put_u64(seconds);
+
+        self.connection.write(bytes.into()).await?;
+
+        let mut r = self.get_response().await?;
+
+        let success = match r.try_get_u8()? {
+            1 => true,
+            0 => false,
+            _ => return Err(AppError::InvalidCommandResponse),
+        };
+
+        Ok(success)
+    }
+
     async fn get_response(&mut self) -> Result<Bytes> {
         self.connection
             .read_bytes()

src/commands/expire.rs

@@ -0,0 +1,37 @@
+use std::io::Cursor;
+
+use bytes::{Buf as _, Bytes};
+
+use crate::{Result, connection::Connection, database::Database, errors::AppError};
+
+#[derive(Debug, Clone)]
+pub struct Expire {
+    key: String,
+    seconds: u64,
+}
+
+impl Expire {
+    pub async fn execute(self, db: &Database, connection: &mut Connection) -> Result<()> {
+        let value = db.expire(&self.key, self.seconds).await?;
+
+        connection
+            .write(Bytes::from_static(if value { &[1] } else { &[0] }))
+            .await?;
+
+        Ok(())
+    }
+
+    pub fn parse(bytes: &mut Cursor<&[u8]>) -> Result<Self> {
+        let key_length = bytes.try_get_u16()? as usize;
+
+        if bytes.remaining() < key_length {
+            return Err(AppError::IncompleteCommandBuffer);
+        }
+
+        let key = String::from_utf8(bytes.copy_to_bytes(key_length).to_vec())?;
+
+        let seconds = bytes.try_get_u64()?;
+
+        Ok(Self { key, seconds })
+    }
+}

src/commands/mod.rs

@@ -1,4 +1,5 @@
 mod delete;
+mod expire;
 mod get;
 mod has;
 mod set;
@@ -8,6 +9,7 @@ use std::io::Cursor;
 
 use bytes::{Buf, BytesMut};
 use delete::Delete;
+use expire::Expire;
 use get::Get;
 use has::Has;
 use set::Set;
@@ -22,6 +24,7 @@ pub enum Command {
     Delete(Delete),
     Has(Has),
     Ttl(Ttl),
+    Expire(Expire),
 }
 
 impl Command {
@@ -32,6 +35,7 @@ impl Command {
             Command::Delete(delete) => delete.execute(db, connection).await,
             Command::Has(has) => has.execute(db, connection).await,
             Command::Ttl(ttl) => ttl.execute(db, connection).await,
+            Command::Expire(expire) => expire.execute(db, connection).await,
         }
     }
 
@@ -56,6 +60,7 @@ impl Command {
             "delete" => Self::Delete(Delete::parse(bytes)?),
             "has" => Self::Has(Has::parse(bytes)?),
             "ttl" => Self::Ttl(Ttl::parse(bytes)?),
+            "expire" => Self::Expire(Expire::parse(bytes)?),
             _ => return Err(AppError::UnknownCommand(command_name)),
         };
 

src/database.rs

@@ -1,6 +1,7 @@
 use std::{
     collections::{BTreeMap, BTreeSet},
     sync::Arc,
+    time::Duration,
 };
 
 use bytes::{BufMut, Bytes, BytesMut};
@@ -138,6 +139,44 @@ impl Database {
             .flatten()
     }
 
+    pub async fn expire(&self, key: &str, seconds: u64) -> Result<bool> {
+        let mut state = self.state.lock().await;
+
+        let expiration = Instant::now() + Duration::from_secs(seconds);
+
+        let notify =
+            state
+                .expirations
+                .iter()
+                .next()
+                .is_none_or(|&(instant, ref next_expiration_key)| {
+                    next_expiration_key == &key || instant > expiration
+                });
+
+        let key = Yarn::copy(key);
+
+        let Some(value) = state.entries.get_mut(&key) else {
+            return Ok(false);
+        };
+
+        let previous_expiration = value.expiration.take();
+        value.expiration = Some(expiration);
+
+        if let Some(previous_expiration) = previous_expiration {
+            state
+                .expirations
+                .remove(&(previous_expiration, key.clone()));
+        };
+
+        state.expirations.insert((expiration, key));
+
+        if notify {
+            self.notify.notify_one();
+        }
+
+        Ok(true)
+    }
+
     pub async fn shutdown(&mut self) {
         self.state.lock().await.shutdown = true;
         self.notify.notify_one();

src/tests.rs

@@ -27,9 +27,13 @@ async fn expiration() -> Result<(), Box<dyn std::error::Error>> {
     assert!(client.has("test-key").await.unwrap());
     assert_eq!(client.ttl("test-key").await.unwrap(), Some(1));
 
+    assert!(client.expire("test-key", 2).await?);
+
     tokio::time::sleep(Duration::from_secs(2)).await;
     assert!(!client.has("test-key").await.unwrap());
 
+    assert!(!client.expire("test-key", 10).await?);
+
     shutdown_tx.send(()).unwrap();
 
     server_handle.await??;