WIP Refactor, code is broken

7 files changed, 541 insertions, 0 deletions

diff --git a/src/imap/command.rs b/src/imap/command.rs
new file mode 100644
index 0000000..adf2f90
--- /dev/null
+++ b/src/imap/command.rs
@@ -0,0 +1,29 @@
+use anyhow::{Error, Result};
+use boitalettres::errors::Error as BalError;
+use boitalettres::proto::{Request, Response};
+use imap_codec::types::core::{AString, Tag};
+use imap_codec::types::fetch_attributes::MacroOrFetchAttributes;
+use imap_codec::types::mailbox::{ListMailbox, Mailbox as MailboxCodec};
+use imap_codec::types::response::{Capability, Code, Data, Response as ImapRes, Status};
+use imap_codec::types::sequence::SequenceSet;
+
+use crate::mailbox::Mailbox;
+use crate::session;
+
+pub struct Command<'a> {
+    tag: Tag,
+    session: &'a mut session::Instance,
+}
+
+// @FIXME better handle errors, our conversions are bad due to my fork of BàL
+// @FIXME store the IMAP state in the session as an enum.
+impl<'a> Command<'a> {
+    pub fn new(tag: Tag, session: &'a mut session::Instance) -> Self {
+        Self { tag, session }
+    }
+
+
+
+
+
+}
diff --git a/src/imap/command/anonymous.rs b/src/imap/command/anonymous.rs
new file mode 100644
index 0000000..e4222f7
--- /dev/null
+++ b/src/imap/command/anonymous.rs
@@ -0,0 +1,60 @@
+
+use boitalettres::proto::{Request, Response};
+use crate::login::ArcLoginProvider;
+use crate::imap::Context;
+
+//--- dispatching
+
+pub async fn dispatch(ctx: Context) -> Result<Response> {
+    match ctx.req.body {
+        CommandBody::Capability => anonymous::capability(ctx).await,
+        CommandBody::Login { username, password } => anonymous::login(ctx, username, password).await,
+        _ => Status::no(Some(ctx.req.tag.clone()), None, "This command is not available in the ANONYMOUS state.")
+            .map(|s| vec![ImapRes::Status(s)])
+            .map_err(Error::msg),
+    }
+}
+
+//--- Command controllers
+
+pub async fn capability(ctx: Context) -> Result<Response> {
+    let capabilities = vec![Capability::Imap4Rev1, Capability::Idle];
+    let res = vec![
+        ImapRes::Data(Data::Capability(capabilities)),
+        ImapRes::Status(
+            Status::ok(Some(ctx.req.tag.clone()), None, "Server capabilities")
+            .map_err(Error::msg)?,
+            ),
+    ];
+    Ok(res)
+}
+
+pub async fn login(ctx: Context, username: AString, password: AString) -> Result<Response> {
+    let (u, p) = (String::try_from(username)?, String::try_from(password)?);
+    tracing::info!(user = %u, "command.login");
+
+    let creds = match ctx.login_provider.login(&u, &p).await {
+        Err(e) => {
+            tracing::debug!(error=%e, "authentication failed");
+            return Ok(vec![ImapRes::Status(
+                    Status::no(Some(ctx.req.tag.clone()), None, "Authentication failed")
+                    .map_err(Error::msg)?,
+                    )]);
+        }
+        Ok(c) => c,
+    };
+
+    let user = flow::User {
+        creds,
+        name: u.clone(),
+    };
+    ctx.state.authenticate(user)?;
+
+    tracing::info!(username=%u, "connected");
+    Ok(vec![
+       //@FIXME we could send a capability status here too
+       ImapRes::Status(
+           Status::ok(Some(ctx.req.tag.clone()), None, "completed").map_err(Error::msg)?,
+           ),
+    ])
+}
diff --git a/src/imap/command/authenticated.rs b/src/imap/command/authenticated.rs
new file mode 100644
index 0000000..188fc56
--- /dev/null
+++ b/src/imap/command/authenticated.rs
@@ -0,0 +1,91 @@
+pub async fn dispatch(ctx: Context) -> Result<Response> {
+    match req.body {
+        CommandBody::Capability => anonymous::capability().await, // we use the same implem for now
+        CommandBody::Lsub { reference, mailbox_wildcard, } => authenticated::lsub(reference, mailbox_wildcard).await,
+        CommandBody::List { reference, mailbox_wildcard, } => authenticated::list(reference, mailbox_wildcard).await,
+        CommandBody::Select { mailbox } => authenticated::select(user, mailbox).await.and_then(|(mailbox, response)| {
+            self.state.select(mailbox);
+            Ok(response)
+        }),
+        _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the AUTHENTICATED state.")
+            .map(|s| vec![ImapRes::Status(s)])
+            .map_err(Error::msg),
+    },
+}
+
+    pub async fn lsub(
+        &self,
+        reference: MailboxCodec,
+        mailbox_wildcard: ListMailbox,
+    ) -> Result<Response> {
+        Ok(vec![ImapRes::Status(
+            Status::bad(Some(self.tag.clone()), None, "Not implemented").map_err(Error::msg)?,
+        )])
+    }
+
+    pub async fn list(
+        &self,
+        reference: MailboxCodec,
+        mailbox_wildcard: ListMailbox,
+    ) -> Result<Response> {
+        Ok(vec![ImapRes::Status(
+            Status::bad(Some(self.tag.clone()), None, "Not implemented").map_err(Error::msg)?,
+        )])
+    }
+
+    /*
+      * TRACE BEGIN ---
+
+
+    Example:    C: A142 SELECT INBOX
+                S: * 172 EXISTS
+                S: * 1 RECENT
+                S: * OK [UNSEEN 12] Message 12 is first unseen
+                S: * OK [UIDVALIDITY 3857529045] UIDs valid
+                S: * OK [UIDNEXT 4392] Predicted next UID
+                S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
+                S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
+                S: A142 OK [READ-WRITE] SELECT completed
+
+      * TRACE END ---
+      */
+    pub async fn select(&mut self, mailbox: MailboxCodec) -> Result<Response> {
+        let name = String::try_from(mailbox)?;
+        let user = match self.session.user.as_ref() {
+            Some(u) => u,
+            _ => {
+                return Ok(vec![ImapRes::Status(
+                    Status::no(Some(self.tag.clone()), None, "Not implemented")
+                        .map_err(Error::msg)?,
+                )])
+            }
+        };
+
+        let mut mb = Mailbox::new(&user.creds, name.clone())?;
+        tracing::info!(username=%user.name, mailbox=%name, "mailbox.selected");
+
+        let sum = mb.summary().await?;
+        tracing::trace!(summary=%sum, "mailbox.summary");
+
+        let body = vec![Data::Exists(sum.exists.try_into()?), Data::Recent(0)];
+
+        self.session.selected = Some(mb);
+
+        let r_unseen = Status::ok(None, Some(Code::Unseen(0)), "").map_err(Error::msg)?;
+        let r_permanentflags = Status::ok(None, Some(Code::
+
+        Ok(vec![
+            ImapRes::Data(Data::Exists(0)),
+            ImapRes::Data(Data::Recent(0)),
+            ImapRes::Data(Data::Flags(vec![]),
+            ImapRes::Status(),
+            ImapRes::Status(),
+            ImapRes::Status()
+                Status::ok(
+                    Some(self.tag.clone()),
+                    Some(Code::ReadWrite),
+                    "Select completed",
+                )
+                .map_err(Error::msg)?,
+        )])
+    }
diff --git a/src/imap/command/selected.rs b/src/imap/command/selected.rs
new file mode 100644
index 0000000..b320ec2
--- /dev/null
+++ b/src/imap/command/selected.rs
@@ -0,0 +1,10 @@
+    pub async fn fetch(
+        &self,
+        sequence_set: SequenceSet,
+        attributes: MacroOrFetchAttributes,
+        uid: bool,
+    ) -> Result<Response> {
+        Ok(vec![ImapRes::Status(
+            Status::bad(Some(self.tag.clone()), None, "Not implemented").map_err(Error::msg)?,
+        )])
+    }
diff --git a/src/imap/flow.rs b/src/imap/flow.rs
new file mode 100644
index 0000000..8ba75bc
--- /dev/null
+++ b/src/imap/flow.rs
@@ -0,0 +1,50 @@
+use crate::mailbox::Mailbox;
+
+pub struct User {
+    pub name: String,
+    pub creds: Credentials,
+}
+
+pub enum State {
+    NotAuthenticated,
+    Authenticated(User),
+    Selected(User, Mailbox),
+    Logout
+}
+pub enum Error {
+    ForbiddenTransition,
+}
+
+// See RFC3501 section 3.
+// https://datatracker.ietf.org/doc/html/rfc3501#page-13
+impl State {
+    pub fn authenticate(&mut self, user: User) -> Result<(), Error> {
+        self = match state {
+            State::NotAuthenticated => State::Authenticated(user),
+            _ => return Err(ForbiddenTransition),
+        };
+        Ok(())
+    }
+
+    pub fn logout(&mut self) -> Self {
+        self = State::Logout;
+        Ok(())
+    }
+
+    pub fn select(&mut self, mailbox: Mailbox) -> Result<(), Error> {
+        self = match state {
+            State::Authenticated(user) => State::Selected(user, mailbox),
+            _ => return Err(ForbiddenTransition),
+        };
+        Ok(())
+    }
+
+    pub fn unselect(state: State) -> Result<(), Error> {
+        self = match state {
+            State::Selected(user, _) => State::Authenticated(user),
+            _ => return Err(ForbiddenTransition),
+        };
+        Ok(())
+    }
+}
+
diff --git a/src/imap/mod.rs b/src/imap/mod.rs
new file mode 100644
index 0000000..45480ce
--- /dev/null
+++ b/src/imap/mod.rs
@@ -0,0 +1,100 @@
+mod session;
+mod flow;
+mod command;
+
+use std::sync::Arc;
+use std::task::{Context, Poll};
+
+use anyhow::Result;
+use boitalettres::errors::Error as BalError;
+use boitalettres::proto::{Request, Response};
+use boitalettres::server::accept::addr::AddrStream;
+use boitalettres::server::Server as ImapServer;
+use futures::future::BoxFuture;
+use futures::future::FutureExt;
+use tower::Service;
+
+use crate::LoginProvider;
+
+/// Server is a thin wrapper to register our Services in BàL
+pub struct Server(ImapServer<AddrIncoming, service::Instance>);
+pub async fn new(
+    config: ImapConfig,
+    login: Arc<dyn LoginProvider + Send + Sync>,
+) -> Result<Server> {
+
+    //@FIXME add a configuration parameter
+    let incoming = AddrIncoming::new(config.bind_addr).await?;
+    let imap = ImapServer::new(incoming).serve(service::Instance::new(login.clone()));
+
+    tracing::info!("IMAP activated, will listen on {:#}", self.imap.incoming.local_addr);
+    Server(imap)
+}
+impl Server {
+    pub async fn run(&self, mut must_exit: watch::Receiver<bool>) -> Result<()> {
+        tracing::info!("IMAP started!");
+        tokio::select! {
+            s = self => s?,
+            _ = must_exit.changed() => tracing::info!("Stopped IMAP server"),
+        }
+
+        Ok(())
+    }
+}
+
+//---
+
+/// Instance is the main Tokio Tower service that we register in BàL.
+/// It receives new connection demands and spawn a dedicated service.
+struct Instance {
+    login_provider: Arc<dyn LoginProvider + Send + Sync>,
+}
+impl Instance {
+    pub fn new(login_provider: Arc<dyn LoginProvider + Send + Sync>) -> Self {
+        Self { login_provider }
+    }
+}
+impl<'a> Service<&'a AddrStream> for Instance {
+    type Response = Connection;
+    type Error = anyhow::Error;
+    type Future = BoxFuture<'static, Result<Self::Response>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        Poll::Ready(Ok(()))
+    }
+
+    fn call(&mut self, addr: &'a AddrStream) -> Self::Future {
+        tracing::info!(remote_addr = %addr.remote_addr, local_addr = %addr.local_addr, "accept");
+        let lp = self.login_provider.clone();
+        async { Ok(Connection::new(lp)) }.boxed()
+    }
+}
+
+//---
+
+/// Connection is the per-connection Tokio Tower service we register in BàL.
+/// It handles a single TCP connection, and thus has a business logic.
+struct Connection {
+    session: session::Manager,
+}
+impl Connection {
+    pub fn new(login_provider: Arc<dyn LoginProvider + Send + Sync>) -> Self {
+        Self {
+            session: session::Manager::new(login_provider),
+        }
+    }
+}
+impl Service<Request> for Connection {
+    type Response = Response;
+    type Error = BalError;
+    type Future = BoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        Poll::Ready(Ok(()))
+    }
+
+    fn call(&mut self, req: Request) -> Self::Future {
+        tracing::debug!("Got request: {:#?}", req);
+        self.session.process(req)
+    }
+}
diff --git a/src/imap/session.rs b/src/imap/session.rs
new file mode 100644
index 0000000..2035634
--- /dev/null
+++ b/src/imap/session.rs
@@ -0,0 +1,201 @@
+use std::sync::Arc;
+
+use anyhow::Error;
+use boitalettres::errors::Error as BalError;
+use boitalettres::proto::{Request, Response};
+use futures::future::BoxFuture;
+use futures::future::FutureExt;
+use imap_codec::types::command::CommandBody;
+use imap_codec::types::response::{Capability, Code, Data, Response as ImapRes, Status};
+use tokio::sync::mpsc::error::TrySendError;
+use tokio::sync::{mpsc, oneshot};
+
+use crate::command::{anonymous,authenticated,selected};
+use crate::login::Credentials;
+use crate::mailbox::Mailbox;
+use crate::LoginProvider;
+
+/* 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<Result<Response, BalError>>,
+}
+
+//-----
+
+pub struct Manager {
+    tx: mpsc::Sender<Message>,
+}
+
+impl Manager {
+    pub fn new(login_provider: ArcLoginProvider) -> Self {
+        let (tx, rx) = mpsc::channel(MAX_PIPELINED_COMMANDS);
+        tokio::spawn(async move {
+            let mut instance = Instance::new(login_provider, rx);
+            instance.start().await;
+        });
+        Self { tx }
+    }
+
+    pub fn process(&self, req: Request) -> BoxFuture<'static, Result<Response, BalError>> {
+        let (tx, rx) = oneshot::channel();
+        let tag = req.tag.clone();
+        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 {
+                    Status::bad(Some(tag), None, "Too fast! Send less pipelined requests!")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(|e| BalError::Text(e.to_string()))
+                }
+                .boxed()
+            }
+            Err(TrySendError::Closed(_)) => {
+                return async {
+                    Status::bad(Some(tag), None, "The session task has exited")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(|e| BalError::Text(e.to_string()))
+                }
+                .boxed()
+            }
+        };
+
+        // @FIXME add a timeout, handle a session that fails.
+        async {
+            match rx.await {
+                Ok(r) => r,
+                Err(e) => {
+                    tracing::warn!("Got error {:#?}", e);
+                    Status::bad(Some(tag), None, "No response from the session handler")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(|e| BalError::Text(e.to_string()))
+                }
+            }
+        }
+        .boxed()
+    }
+}
+
+//-----
+
+pub struct Context<'a> {
+    req: &'a Request,
+    state: &'a mut flow::State,
+    login: ArcLoginProvider,
+}
+
+pub struct Instance {
+    rx: mpsc::Receiver<Message>,
+
+    pub login_provider: ArcLoginProvider,
+    pub state: flow::State,
+}
+impl Instance {
+    fn new(
+        login_provider: ArcLoginProvider,
+        rx: mpsc::Receiver<Message>,
+    ) -> Self {
+        Self {
+            login_provider,
+            rx,
+            state: flow::State::NotAuthenticated,
+        }
+    }
+
+    //@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 ctx = Context { req: &msg.req, state: &mut self.state, login: self.login_provider };
+
+            // Command behavior is modulated by the state.
+            // To prevent state error, we handle the same command in separate code path depending
+            // on the State.
+            let cmd_res =  match self.state {
+                flow::State::NotAuthenticated => anonymous::dispatch(ctx).await, 
+                flow::State::Authenticated(user) => authenticated::dispatch(ctx).await,
+                flow::State::Selected(user, mailbox) => selected::dispatch(ctx).await,
+                flow::State::Logout => Status::bad(Some(ctx.req.tag.clone()), None, "No commands are allowed in the LOGOUT state.")
+                    .map(|s| vec![ImapRes::Status(s)])
+                    .map_err(Error::msg),
+            };
+
+/*
+
+                match req.body {
+                    CommandBody::Capability => anonymous::capability().await,
+                    CommandBody::Login { username, password } => anonymous::login(self.login_provider, username, password).await.and_then(|(user, response)| {
+                        self.state.authenticate(user)?;
+                        Ok(response)
+                    },
+                    _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the ANONYMOUS state.")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(Error::msg),
+
+                },
+                flow::State::Authenticated(user) => match req.body {
+                    CommandBody::Capability => anonymous::capability().await, // we use the same implem for now
+                    CommandBody::Lsub { reference, mailbox_wildcard, } => authenticated::lsub(reference, mailbox_wildcard).await,
+                    CommandBody::List { reference, mailbox_wildcard, } => authenticated::list(reference, mailbox_wildcard).await,
+                    CommandBody::Select { mailbox } => authenticated::select(user, mailbox).await.and_then(|(mailbox, response)| {
+                        self.state.select(mailbox);
+                        Ok(response)
+                    }),
+                    _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the AUTHENTICATED state.")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(Error::msg),
+                },
+                flow::State::Selected(user, mailbox) => match req.body {
+                    CommandBody::Capability => anonymous::capability().await, // we use the same implem for now
+                    CommandBody::Fetch { sequence_set, attributes, uid, } => selected::fetch(sequence_set, attributes, uid).await,
+                    _ => Status::no(Some(msg.req.tag.clone()), None, "This command is not available in the SELECTED state.")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(Error::msg),
+                },
+                flow::State::Logout => Status::bad(Some(msg.req.tag.clone()), None, "No commands are allowed in the LOGOUT state.")
+                    .map(|s| vec![ImapRes::Status(s)])
+                    .map_err(Error::msg),
+            }
+            */
+
+            let imap_res = match cmd_res {
+                Ok(new_state, imap_res) => {
+                    self.state = new_state;
+                    Ok(imap_res)
+                },
+                Err(e) if Ok(be) = e.downcast::<BalError>() => Err(be),
+                Err(e) => {
+                    tracing::warn!(error=%e, "internal.error");
+                    Ok(Status::bad(Some(msg.req.tag.clone()), None, "Internal error")
+                        .map(|s| vec![ImapRes::Status(s)])
+                        .map_err(|e| BalError::Text(e.to_string())))
+                }
+            };
+
+            //@FIXME I think we should quit this thread on error and having our manager watch it,
+            // and then abort the session as it is corrupted.
+            msg.tx.send(imap_res).unwrap_or_else(|e| {
+                tracing::warn!("failed to send imap response to manager: {:#?}", e)
+            });
+        }
+
+        //@FIXME add more info about the runner
+        tracing::debug!("exiting runner");
+    }
+}