From 8e7583a32f7297fe2ea81c45fe319dd76e080b31 Mon Sep 17 00:00:00 2001
From: Manos Pitsidianakis <el13635@mail.ntua.gr>
Date: Sun, 29 Nov 2020 19:33:23 +0200
Subject: [PATCH] melib/imap: don't clear mailbox counts before fetching

---
 melib/src/backends.rs      | 13 ++++---------
 melib/src/backends/imap.rs | 27 +++++++++++++++++++--------
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/melib/src/backends.rs b/melib/src/backends.rs
index 8e8e8f81f..4b01d47a7 100644
--- a/melib/src/backends.rs
+++ b/melib/src/backends.rs
@@ -647,15 +647,10 @@ impl LazyCountSet {
         }
     }
 
-    pub fn insert_existing_set(&mut self, set: BTreeSet<EnvelopeHash>) -> bool {
-        if self.not_yet_seen < set.len() {
-            false
-        } else {
-            let old_len = self.set.len();
-            self.set.extend(set.into_iter());
-            self.not_yet_seen -= self.set.len() - old_len;
-            true
-        }
+    pub fn insert_existing_set(&mut self, set: BTreeSet<EnvelopeHash>) {
+        let old_len = self.set.len();
+        self.set.extend(set.into_iter());
+        self.not_yet_seen = self.not_yet_seen.saturating_sub(self.set.len() - old_len);
     }
 
     #[inline(always)]
diff --git a/melib/src/backends/imap.rs b/melib/src/backends/imap.rs
index 135ab90ff..cd4b809c3 100644
--- a/melib/src/backends/imap.rs
+++ b/melib/src/backends/imap.rs
@@ -343,12 +343,24 @@ impl MailBackend for ImapType {
             cache_handle,
         };
 
+        /* do this in a closure to prevent recursion limit error in async_stream macro */
+        let prepare_cl = |f: &ImapMailbox| {
+            f.set_warm(true);
+            if let Ok(mut exists) = f.exists.lock() {
+                let total = exists.len();
+                exists.clear();
+                exists.set_not_yet_seen(total);
+            }
+            if let Ok(mut unseen) = f.unseen.lock() {
+                let total = unseen.len();
+                unseen.clear();
+                unseen.set_not_yet_seen(total);
+            }
+        };
         Ok(Box::pin(async_stream::try_stream! {
             {
                 let f = &state.uid_store.mailboxes.lock().await[&mailbox_hash];
-                f.exists.lock().unwrap().clear();
-                f.unseen.lock().unwrap().clear();
-                f.set_warm(true);
+                prepare_cl(f);
                 if f.no_select {
                     yield vec![];
                     return;
@@ -1629,7 +1641,7 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                             let f = &state.uid_store.mailboxes.lock().await[&state.mailbox_hash];
                             (f.exists.clone(), f.unseen.clone())
                         };
-                        unseen.lock().unwrap().insert_set(
+                        unseen.lock().unwrap().insert_existing_set(
                             cached_payload
                                 .iter()
                                 .filter_map(|env| {
@@ -1641,10 +1653,9 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                                 })
                                 .collect(),
                         );
-                        mailbox_exists
-                            .lock()
-                            .unwrap()
-                            .insert_set(cached_payload.iter().map(|env| env.hash()).collect::<_>());
+                        mailbox_exists.lock().unwrap().insert_existing_set(
+                            cached_payload.iter().map(|env| env.hash()).collect::<_>(),
+                        );
                         return Ok(cached_payload);
                     }
                 }