feat: IMAP COMPRESS support

Author: link2xt

Cargo.lock

@@ -41,7 +41,7 @@ ratelimit = { path = "./deltachat-ratelimit" }
 anyhow = { workspace = true }
 async-broadcast = "0.7.1"
 async-channel = { workspace = true }
-async-imap = { version = "0.10.1", default-features = false, features = ["runtime-tokio"] }
+async-imap = { git = "https://github.com/async-email/async-imap.git", default-features = false, features = ["runtime-tokio", "compress"], branch = "link2xt/imap-compress" }
 async-native-tls = { version = "0.5", default-features = false, features = ["runtime-tokio"] }
 async-smtp = { version = "0.9", default-features = false, features = ["runtime-tokio"] }
 async_zip = { version = "0.0.12", default-features = false, features = ["deflate", "fs"] }

Cargo.toml

@@ -25,6 +25,10 @@ pub(crate) struct Capabilities {
     /// <https://tools.ietf.org/html/rfc5464>
     pub can_metadata: bool,
 
+    /// True if the server has COMPRESS=DEFLATE capability as defined in
+    /// <https://tools.ietf.org/html/rfc4978>
+    pub can_compress: bool,
+
     /// True if the server supports XDELTAPUSH capability.
     /// This capability means setting /private/devicetoken IMAP METADATA
     /// on the INBOX results in new mail notifications

src/imap/capabilities.rs

@@ -69,6 +69,7 @@ async fn determine_capabilities(
         can_check_quota: caps.has_str("QUOTA"),
         can_condstore: caps.has_str("CONDSTORE"),
         can_metadata: caps.has_str("METADATA"),
+        can_compress: caps.has_str("COMPRESS=DEFLATE"),
         can_push: caps.has_str("XDELTAPUSH"),
         is_chatmail: caps.has_str("XCHATMAIL"),
         server_id,
@@ -90,7 +91,19 @@ impl Client {
             .await
             .map_err(|(err, _client)| err)?;
         let capabilities = determine_capabilities(&mut session).await?;
-        Ok(Session::new(session, capabilities))
+
+        if capabilities.can_compress {
+            let compressed_session = session
+                .compress(|s| {
+                    let session_stream: Box<dyn SessionStream> = Box::new(s);
+                    session_stream
+                })
+                .await
+                .context("Failed to enable IMAP compression")?;
+            Ok(Session::new(compressed_session, capabilities))
+        } else {
+            Ok(Session::new(session, capabilities))
+        }
     }
 
     pub(crate) async fn authenticate(

src/imap/client.rs

@@ -50,6 +50,11 @@ impl<T: SessionStream> SessionStream for ShadowsocksStream<T> {
         self.stream.get_mut().set_read_timeout(timeout)
     }
 }
+impl<T: SessionStream> SessionStream for async_imap::deflate::DeflateStream<T> {
+    fn set_read_timeout(&mut self, _timeout: Option<Duration>) {
+        //self.stream.get_mut().set_read_timeout(timeout)
+    }
+}
 
 /// Session stream with a read buffer.
 pub(crate) trait SessionBufStream: SessionStream + AsyncBufRead {}