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-rw-r--r--src/session.rs102
1 files changed, 102 insertions, 0 deletions
diff --git a/src/session.rs b/src/session.rs
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+use std::sync::Arc;
+
+use boitalettres::proto::{Request, Response};
+use boitalettres::errors::Error as BalError;
+use imap_codec::types::command::CommandBody;
+use tokio::sync::{oneshot,mpsc};
+use tokio::sync::mpsc::error::TrySendError;
+use futures::future::BoxFuture;
+use futures::future::FutureExt;
+
+use crate::command;
+use crate::login::Credentials;
+use crate::mailstore::Mailstore;
+use crate::mailbox::Mailbox;
+
+/* This constant configures backpressure in the system,
+ * or more specifically, how many pipelined messages are allowed
+ * before refusing them
+ */
+const MAX_PIPELINED_COMMANDS: usize = 10;
+
+struct Message {
+ req: Request,
+ tx: oneshot::Sender<Response>,
+}
+
+pub struct Manager {
+ tx: mpsc::Sender<Message>,
+}
+
+//@FIXME we should garbage collect the Instance when the Manager is destroyed.
+impl Manager {
+ pub fn new(mailstore: Arc<Mailstore>) -> Self {
+ let (tx, mut rx) = mpsc::channel(MAX_PIPELINED_COMMANDS);
+ tokio::spawn(async move {
+ let mut instance = Instance::new(mailstore, rx);
+ instance.start().await;
+ });
+ Self { tx }
+ }
+
+ pub fn process(&self, req: Request) -> BoxFuture<'static, Result<Response, BalError>> {
+ let (tx, rx) = oneshot::channel();
+ let msg = Message { req, tx };
+
+ // We use try_send on a bounded channel to protect the daemons from DoS.
+ // Pipelining requests in IMAP are a special case: they should not occure often
+ // and in a limited number (like 3 requests). Someone filling the channel
+ // will probably be malicious so we "rate limit" them.
+ match self.tx.try_send(msg) {
+ Ok(()) => (),
+ Err(TrySendError::Full(_)) => return async { Response::bad("Too fast! Send less pipelined requests!") }.boxed(),
+ Err(TrySendError::Closed(_)) => return async { Response::bad("The session task has exited") }.boxed(),
+ };
+
+ // @FIXME add a timeout, handle a session that fails.
+ async {
+ rx.await.or_else(|e| {
+ tracing::warn!("Got error {:#?}", e);
+ Response::bad("No response from the session handler")
+ })
+ }.boxed()
+ }
+}
+
+pub struct Instance {
+ rx: mpsc::Receiver<Message>,
+
+ pub mailstore: Arc<Mailstore>,
+ pub creds: Option<Credentials>,
+ pub selected: Option<Mailbox>,
+}
+impl Instance {
+ fn new(mailstore: Arc<Mailstore>, rx: mpsc::Receiver<Message>) -> Self {
+ Self { mailstore, rx, creds: None, selected: None, }
+ }
+
+ //@FIXME add a function that compute the runner's name from its local info
+ // to ease debug
+ // fn name(&self) -> String { }
+
+ async fn start(&mut self) {
+ //@FIXME add more info about the runner
+ tracing::debug!("starting runner");
+
+ while let Some(msg) = self.rx.recv().await {
+ let mut cmd = command::Command::new(msg.req.tag, self);
+ let _ = match msg.req.body {
+ CommandBody::Capability => cmd.capability().await,
+ CommandBody::Login { username, password } => cmd.login(username, password).await,
+ CommandBody::Lsub { reference, mailbox_wildcard } => cmd.lsub(reference, mailbox_wildcard).await,
+ CommandBody::List { reference, mailbox_wildcard } => cmd.list(reference, mailbox_wildcard).await,
+ CommandBody::Select { mailbox } => cmd.select(mailbox).await,
+ CommandBody::Fetch { sequence_set, attributes, uid } => cmd.fetch(sequence_set, attributes, uid).await,
+ _ => Response::bad("Error in IMAP command received by server."),
+ };
+ }
+
+ //@FIXME add more info about the runner
+ tracing::debug!("exiting runner");
+ }
+}