refactor: get rid of ImapActionResult

src/download.rs

@@ -3,13 +3,13 @@
 use std::cmp::max;
 use std::collections::BTreeMap;
 
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, bail, Result};
 use deltachat_derive::{FromSql, ToSql};
 use serde::{Deserialize, Serialize};
 
 use crate::config::Config;
 use crate::context::Context;
-use crate::imap::{session::Session, ImapActionResult};
+use crate::imap::session::Session;
 use crate::message::{Message, MsgId, Viewtype};
 use crate::mimeparser::{MimeMessage, Part};
 use crate::tools::time;
@@ -154,7 +154,7 @@ pub(crate) async fn download_msg(
         return Err(anyhow!("Call download_full() again to try over."));
     };
 
-    match session
+    session
         .fetch_single_msg(
             context,
             &server_folder,
@@ -162,13 +162,8 @@ pub(crate) async fn download_msg(
             server_uid,
             msg.rfc724_mid.clone(),
         )
-        .await
+        .await?;
-    {
+    Ok(())
-        ImapActionResult::RetryLater | ImapActionResult::Failed => {
-            Err(anyhow!("Call download_full() again to try over."))
-        }
-        ImapActionResult::Success => Ok(()),
-    }
 }
 
 impl Session {
@@ -183,20 +178,19 @@ impl Session {
         uidvalidity: u32,
         uid: u32,
         rfc724_mid: String,
-    ) -> ImapActionResult {
+    ) -> Result<()> {
-        if let Some(imapresult) = self
+        if uid == 0 {
-            .prepare_imap_operation_on_msg(context, folder, uid)
+            bail!("Attempt to fetch UID 0");
-            .await
-        {
-            return imapresult;
         }
 
+        self.select_folder(context, Some(folder)).await?;
+
         // we are connected, and the folder is selected
         info!(context, "Downloading message {}/{} fully...", folder, uid);
 
         let mut uid_message_ids: BTreeMap<u32, String> = BTreeMap::new();
         uid_message_ids.insert(uid, rfc724_mid);
-        let (last_uid, _received) = match self
+        let (last_uid, _received) = self
             .fetch_many_msgs(
                 context,
                 folder,
@@ -206,16 +200,11 @@ impl Session {
                 false,
                 false,
             )
-            .await
+            .await?;
-        {
-            Ok(res) => res,
-            Err(_) => return ImapActionResult::Failed,
-        };
         if last_uid.is_none() {
-            ImapActionResult::Failed
+            bail!("Failed to fetch UID {uid}");
-        } else {
-            ImapActionResult::Success
         }
+        Ok(())
     }
 }
 

src/imap.rs

@@ -54,13 +54,6 @@ use session::Session;
 
 pub(crate) const GENERATED_PREFIX: &str = "GEN_";
 
-#[derive(Debug, Display, Clone, Copy, PartialEq, Eq)]
-pub enum ImapActionResult {
-    Failed,
-    RetryLater,
-    Success,
-}
-
 const RFC724MID_UID: &str = "(UID BODY.PEEK[HEADER.FIELDS (\
                              MESSAGE-ID \
                              X-MICROSOFT-ORIGINAL-MESSAGE-ID\
@@ -1475,33 +1468,6 @@ impl Session {
         Ok(())
     }
 
-    pub(crate) async fn prepare_imap_operation_on_msg(
-        &mut self,
-        context: &Context,
-        folder: &str,
-        uid: u32,
-    ) -> Option<ImapActionResult> {
-        if uid == 0 {
-            return Some(ImapActionResult::RetryLater);
-        }
-
-        match self.select_folder(context, Some(folder)).await {
-            Ok(_) => None,
-            Err(select_folder::Error::ConnectionLost) => {
-                warn!(context, "Lost imap connection");
-                Some(ImapActionResult::RetryLater)
-            }
-            Err(select_folder::Error::BadFolderName(folder_name)) => {
-                warn!(context, "invalid folder name: {:?}", folder_name);
-                Some(ImapActionResult::Failed)
-            }
-            Err(err) => {
-                warn!(context, "failed to select folder {:?}: {:#}", folder, err);
-                Some(ImapActionResult::RetryLater)
-            }
-        }
-    }
-
     /// Attempts to configure mvbox.
     ///
     /// Tries to find any folder in the given list of `folders`. If none is found, tries to create

src/imap/select_folder.rs

@@ -52,7 +52,7 @@ impl ImapSession {
     /// Selects a folder, possibly updating uid_validity and, if needed,
     /// expunging the folder to remove delete-marked messages.
     /// Returns whether a new folder was selected.
-    pub(super) async fn select_folder(
+    pub(crate) async fn select_folder(
         &mut self,
         context: &Context,
         folder: Option<&str>,
@@ -256,7 +256,7 @@ impl ImapSession {
 }
 
 #[derive(PartialEq, Debug, Copy, Clone, Eq)]
-pub(super) enum NewlySelected {
+pub(crate) enum NewlySelected {
     /// The folder was newly selected during this call to select_folder().
     Yes,
     /// No SELECT command was run because the folder already was selected