melib/imap: don't fail utterly if cache fails on fetch

Show notice to user, and then try a fresh fetch. Also try resetting the
cache if possible.

5 files changed, 228 insertions, 55 deletions

diff --git a/melib/src/backends/imap.rs b/melib/src/backends/imap.rs
index a74c5854..b9dc95b8 100644
--- a/melib/src/backends/imap.rs
+++ b/melib/src/backends/imap.rs
@@ -298,6 +298,27 @@ impl MailBackend for ImapType {
         &mut self,
         mailbox_hash: MailboxHash,
     ) -> Result<Pin<Box<dyn Stream<Item = Result<Vec<Envelope>>> + Send + 'static>>> {
+        let cache_handle = {
+            #[cfg(feature = "sqlite3")]
+            if self.uid_store.keep_offline_cache {
+                match cache::Sqlite3Cache::get(self.uid_store.clone()).chain_err_summary(|| {
+                    format!(
+                        "Could not initialize cache for IMAP account {}",
+                        self.uid_store.account_name
+                    )
+                }) {
+                    Ok(v) => Some(v),
+                    Err(err) => {
+                        (self.uid_store.event_consumer)(self.uid_store.account_hash, err.into());
+                        None
+                    }
+                }
+            } else {
+                None
+            }
+            #[cfg(not(feature = "sqlite3"))]
+            None
+        };
         let mut state = FetchState {
             stage: if self.uid_store.keep_offline_cache {
                 FetchStage::InitialCache
@@ -307,6 +328,7 @@ impl MailBackend for ImapType {
             connection: self.connection.clone(),
             mailbox_hash,
             uid_store: self.uid_store.clone(),
+            cache_handle,
         };
 
         Ok(Box::pin(async_stream::try_stream! {
@@ -1455,6 +1477,7 @@ struct FetchState {
     connection: Arc<FutureMutex<ImapConnection>>,
     mailbox_hash: MailboxHash,
     uid_store: Arc<UIDStore>,
+    cache_handle: Option<Box<dyn cache::ImapCache>>,
 }
 
 async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
@@ -1468,6 +1491,17 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                     .await
                     .init_mailbox(state.mailbox_hash)
                     .await?;
+                if let Some(ref mut cache_handle) = state.cache_handle {
+                    if let Err(err) = cache_handle
+                        .update_mailbox(state.mailbox_hash, &select_response)
+                        .chain_err_summary(|| {
+                            format!("Could not update cache for mailbox {}.", state.mailbox_hash)
+                        })
+                    {
+                        (state.uid_store.event_consumer)(state.uid_store.account_hash, err.into());
+                    }
+                }
+
                 if select_response.exists == 0 {
                     state.stage = FetchStage::Finished;
                     return Ok(Vec::new());
@@ -1478,36 +1512,57 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                 continue;
             }
             FetchStage::InitialCache => {
-                if let Some(cached_payload) = cache::fetch_cached_envs(state).await? {
-                    state.stage = FetchStage::ResyncCache;
-                    debug!(
-                        "fetch_hlpr fetch_cached_envs payload {} len for mailbox_hash {}",
-                        cached_payload.len(),
-                        state.mailbox_hash
-                    );
-                    let (mailbox_exists, unseen) = {
-                        let f = &state.uid_store.mailboxes.lock().await[&state.mailbox_hash];
-                        (f.exists.clone(), f.unseen.clone())
-                    };
-                    unseen.lock().unwrap().insert_existing_set(
-                        cached_payload
-                            .iter()
-                            .filter_map(|env| {
-                                if !env.is_seen() {
-                                    Some(env.hash())
-                                } else {
-                                    None
-                                }
-                            })
-                            .collect(),
-                    );
-                    mailbox_exists.lock().unwrap().insert_existing_set(
-                        cached_payload.iter().map(|env| env.hash()).collect::<_>(),
-                    );
-                    return Ok(cached_payload);
+                match cache::fetch_cached_envs(state).await {
+                    Err(err) => {
+                        crate::log(
+                            format!(
+                                "IMAP cache error: could not fetch cache for {}. Reason: {}",
+                                state.uid_store.account_name, err
+                            ),
+                            crate::ERROR,
+                        );
+                        /* Try resetting the database */
+                        if let Some(ref mut cache_handle) = state.cache_handle {
+                            if let Err(err) = cache_handle.reset() {
+                                crate::log(format!("IMAP cache error: could not reset cache for {}. Reason: {}", state.uid_store.account_name, err), crate::ERROR);
+                            }
+                        }
+                        state.stage = FetchStage::InitialFresh;
+                        continue;
+                    }
+                    Ok(None) => {
+                        state.stage = FetchStage::InitialFresh;
+                        continue;
+                    }
+                    Ok(Some(cached_payload)) => {
+                        state.stage = FetchStage::ResyncCache;
+                        debug!(
+                            "fetch_hlpr fetch_cached_envs payload {} len for mailbox_hash {}",
+                            cached_payload.len(),
+                            state.mailbox_hash
+                        );
+                        let (mailbox_exists, unseen) = {
+                            let f = &state.uid_store.mailboxes.lock().await[&state.mailbox_hash];
+                            (f.exists.clone(), f.unseen.clone())
+                        };
+                        unseen.lock().unwrap().insert_existing_set(
+                            cached_payload
+                                .iter()
+                                .filter_map(|env| {
+                                    if !env.is_seen() {
+                                        Some(env.hash())
+                                    } else {
+                                        None
+                                    }
+                                })
+                                .collect(),
+                        );
+                        mailbox_exists.lock().unwrap().insert_existing_set(
+                            cached_payload.iter().map(|env| env.hash()).collect::<_>(),
+                        );
+                        return Ok(cached_payload);
+                    }
                 }
-                state.stage = FetchStage::InitialFresh;
-                continue;
             }
             FetchStage::ResyncCache => {
                 let mailbox_hash = state.mailbox_hash;
@@ -1526,6 +1581,7 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                     ref connection,
                     mailbox_hash,
                     ref uid_store,
+                    ref mut cache_handle,
                 } = state;
                 let mailbox_hash = *mailbox_hash;
                 let mut our_unseen: BTreeSet<EnvelopeHash> = BTreeSet::default();
@@ -1608,17 +1664,21 @@ async fn fetch_hlpr(state: &mut FetchState) -> Result<Vec<Envelope>> {
                             }
                         }
                     }
-                    #[cfg(feature = "sqlite3")]
-                    if uid_store.keep_offline_cache {
-                        let mut cache_handle = cache::Sqlite3Cache::get(uid_store.clone())?;
-                        debug!(cache_handle
+                    if let Some(ref mut cache_handle) = cache_handle {
+                        if let Err(err) = debug!(cache_handle
                             .insert_envelopes(mailbox_hash, &v)
                             .chain_err_summary(|| {
                                 format!(
                                     "Could not save envelopes in cache for mailbox {}",
                                     mailbox_path
                                 )
-                            }))?;
+                            }))
+                        {
+                            (state.uid_store.event_consumer)(
+                                state.uid_store.account_hash,
+                                err.into(),
+                            );
+                        }
                     }
 
                     for FetchResponse {
diff --git a/melib/src/backends/imap/cache.rs b/melib/src/backends/imap/cache.rs
index 53ec5d9b..ad2b1301 100644
--- a/melib/src/backends/imap/cache.rs
+++ b/melib/src/backends/imap/cache.rs
@@ -54,7 +54,8 @@ pub struct CachedEnvelope {
     pub modsequence: Option<ModSequence>,
 }
 
-pub trait ImapCache: Send {
+pub trait ImapCache: Send + core::fmt::Debug {
+    fn reset(&mut self) -> Result<()>;
     fn mailbox_state(&mut self, mailbox_hash: MailboxHash) -> Result<Option<()>>;
 
     fn find_envelope(
@@ -69,6 +70,12 @@ pub trait ImapCache: Send {
         refresh_events: &[(UID, RefreshEvent)],
     ) -> Result<()>;
 
+    fn update_mailbox(
+        &mut self,
+        mailbox_hash: MailboxHash,
+        select_response: &SelectResponse,
+    ) -> Result<()>;
+
     fn insert_envelopes(
         &mut self,
         mailbox_hash: MailboxHash,
@@ -99,6 +106,7 @@ mod sqlite3_m {
 
     type Sqlite3UID = i32;
 
+    #[derive(Debug)]
     pub struct Sqlite3Cache {
         connection: crate::sqlite3::Connection,
         loaded_mailboxes: BTreeSet<MailboxHash>,
@@ -178,6 +186,10 @@ mod sqlite3_m {
     }
 
     impl ImapCache for Sqlite3Cache {
+        fn reset(&mut self) -> Result<()> {
+            sqlite3::reset_db(&DB_DESCRIPTION, Some(self.uid_store.account_name.as_str()))
+        }
+
         fn mailbox_state(&mut self, mailbox_hash: MailboxHash) -> Result<Option<()>> {
             if self.loaded_mailboxes.contains(&mailbox_hash) {
                 return Ok(Some(()));
@@ -293,6 +305,64 @@ mod sqlite3_m {
             Ok(())
         }
 
+        fn update_mailbox(
+            &mut self,
+            mailbox_hash: MailboxHash,
+            select_response: &SelectResponse,
+        ) -> Result<()> {
+            if self.mailbox_state(mailbox_hash)?.is_none() {
+                return self.clear(mailbox_hash, select_response);
+            }
+
+            if let Some(Ok(highestmodseq)) = select_response.highestmodseq {
+                self.connection
+                    .execute(
+                        "UPDATE mailbox SET flags=?1, highestmodseq =?2 where mailbox_hash = ?3;",
+                        sqlite3::params![
+                            select_response
+                                .flags
+                                .1
+                                .iter()
+                                .map(|s| s.as_str())
+                                .collect::<Vec<&str>>()
+                                .join("\0")
+                                .as_bytes(),
+                            highestmodseq,
+                            mailbox_hash as i64
+                        ],
+                    )
+                    .chain_err_summary(|| {
+                        format!(
+                            "Could not update mailbox {} in header_cache of account {}",
+                            mailbox_hash, self.uid_store.account_name
+                        )
+                    })?;
+            } else {
+                self.connection
+                    .execute(
+                        "UPDATE mailbox SET flags=?1 where mailbox_hash = ?2;",
+                        sqlite3::params![
+                            select_response
+                                .flags
+                                .1
+                                .iter()
+                                .map(|s| s.as_str())
+                                .collect::<Vec<&str>>()
+                                .join("\0")
+                                .as_bytes(),
+                            mailbox_hash as i64
+                        ],
+                    )
+                    .chain_err_summary(|| {
+                        format!(
+                            "Could not update mailbox {} in header_cache of account {}",
+                            mailbox_hash, self.uid_store.account_name
+                        )
+                    })?;
+            }
+            Ok(())
+        }
+
         fn envelopes(&mut self, mailbox_hash: MailboxHash) -> Result<Option<Vec<EnvelopeHash>>> {
             debug!("envelopes mailbox_hash {}", mailbox_hash);
             if debug!(self.mailbox_state(mailbox_hash)?.is_none()) {
@@ -581,6 +651,7 @@ pub(super) async fn fetch_cached_envs(state: &mut FetchState) -> Result<Option<V
         ref mut connection,
         mailbox_hash,
         ref uid_store,
+        cache_handle: _,
     } = state;
     debug!(uid_store.keep_offline_cache);
     let mailbox_hash = *mailbox_hash;
@@ -638,6 +709,8 @@ pub use default_m::*;
 
 #[cfg(not(feature = "sqlite3"))]
 mod default_m {
+    use super::*;
+    #[derive(Debug)]
     pub struct DefaultCache;
 
     impl DefaultCache {
@@ -647,6 +720,10 @@ mod default_m {
     }
 
     impl ImapCache for DefaultCache {
+        fn reset(&mut self) -> Result<()> {
+            Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
+        }
+
         fn mailbox_state(&mut self, _mailbox_hash: MailboxHash) -> Result<Option<()>> {
             Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
         }
@@ -671,6 +748,14 @@ mod default_m {
             Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
         }
 
+        fn update_mailbox(
+            &mut self,
+            _mailbox_hash: MailboxHash,
+            _select_response: &SelectResponse,
+        ) -> Result<()> {
+            Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
+        }
+
         fn update(
             &mut self,
             _mailbox_hash: MailboxHash,
@@ -686,5 +771,13 @@ mod default_m {
         ) -> Result<Option<CachedEnvelope>> {
             Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
         }
+
+        fn rfc822(
+            &mut self,
+            _identifier: std::result::Result<UID, EnvelopeHash>,
+            _mailbox_hash: MailboxHash,
+        ) -> Result<Option<Vec<u8>>> {
+            Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
+        }
     }
 }
diff --git a/melib/src/backends/imap/cache/sync.rs b/melib/src/backends/imap/cache/sync.rs
index 7569fc82..1ff2e968 100644
--- a/melib/src/backends/imap/cache/sync.rs
+++ b/melib/src/backends/imap/cache/sync.rs
@@ -37,8 +37,6 @@ impl ImapConnection {
             return Ok(None);
         }
 
-        self.select_mailbox(mailbox_hash, &mut String::new(), false)
-            .await?;
         match self.sync_policy {
             SyncPolicy::None => Ok(None),
             SyncPolicy::Basic => self.resync_basic(cache_handle, mailbox_hash).await,
@@ -87,15 +85,10 @@ impl ImapConnection {
         debug!("build_cache {}", mailbox_hash);
         let mut response = String::with_capacity(8 * 1024);
         // 1 get uidvalidity, highestmodseq
-        self.select_mailbox(mailbox_hash, &mut response, true)
-            .await?;
-        let select_response =
-            protocol_parser::select_response(&response).chain_err_summary(|| {
-                format!(
-                    "Could not parse select response for mailbox {}",
-                    mailbox_hash
-                )
-            })?;
+        let select_response = self
+            .select_mailbox(mailbox_hash, &mut response, true)
+            .await?
+            .unwrap();
         self.uid_store
             .uidvalidity
             .lock()
@@ -159,9 +152,10 @@ impl ImapConnection {
         let mut new_unseen = BTreeSet::default();
         debug!("current_uidvalidity is {}", current_uidvalidity);
         debug!("max_uid is {}", max_uid);
-        self.select_mailbox(mailbox_hash, &mut response, true)
-            .await?;
-        let select_response = protocol_parser::select_response(&response)?;
+        let select_response = self
+            .select_mailbox(mailbox_hash, &mut response, true)
+            .await?
+            .unwrap();
         debug!(
             "select_response.uidvalidity is {}",
             select_response.uidvalidity
@@ -171,6 +165,7 @@ impl ImapConnection {
             cache_handle.clear(mailbox_hash, &select_response)?;
             return Ok(None);
         }
+        cache_handle.update_mailbox(mailbox_hash, &select_response)?;
 
         // 2.  tag1 UID FETCH <lastseenuid+1>:* <descriptors>
         self.send_command(
@@ -403,9 +398,10 @@ impl ImapConnection {
         debug!("current_uidvalidity is {}", cached_uidvalidity);
         debug!("max_uid is {}", cached_max_uid);
         // 1. check UIDVALIDITY. If fail, discard cache and rebuild
-        self.select_mailbox(mailbox_hash, &mut response, true)
-            .await?;
-        let select_response = protocol_parser::select_response(&response)?;
+        let select_response = self
+            .select_mailbox(mailbox_hash, &mut response, true)
+            .await?
+            .unwrap();
         debug!(
             "select_response.uidvalidity is {}",
             select_response.uidvalidity
@@ -436,6 +432,7 @@ impl ImapConnection {
             }
             return self.resync_basic(cache_handle, mailbox_hash).await;
         }
+        cache_handle.update_mailbox(mailbox_hash, &select_response)?;
         let new_highestmodseq = select_response.highestmodseq.unwrap().unwrap();
         let mut refresh_events = vec![];
         // 1b) Check the mailbox HIGHESTMODSEQ.
@@ -662,8 +659,7 @@ impl ImapConnection {
          * returns READ-ONLY for both cases) */
         let mut select_response = self
             .select_mailbox(mailbox_hash, &mut response, true)
-            .await
-            .chain_err_summary(|| format!("Could not select mailbox {}", mailbox_path))?
+            .await?
             .unwrap();
         debug!(
             "mailbox: {} select_response: {:?}",
diff --git a/melib/src/backends/imap/connection.rs b/melib/src/backends/imap/connection.rs
index 444e2b1f..877347dc 100644
--- a/melib/src/backends/imap/connection.rs
+++ b/melib/src/backends/imap/connection.rs
@@ -762,7 +762,9 @@ impl ImapConnection {
         self.read_response(ret, RequiredResponses::SELECT_REQUIRED)
             .await?;
         debug!("select response {}", ret);
-        let select_response = protocol_parser::select_response(&ret)?;
+        let select_response = protocol_parser::select_response(&ret).chain_err_summary(|| {
+            format!("Could not parse select response for mailbox {}", imap_path)
+        })?;
         {
             if self.uid_store.keep_offline_cache {
                 #[cfg(not(feature = "sqlite3"))]
diff --git a/melib/src/sqlite3.rs b/melib/src/sqlite3.rs
index b001aae1..79ab77f2 100644
--- a/melib/src/sqlite3.rs
+++ b/melib/src/sqlite3.rs
@@ -96,6 +96,28 @@ pub fn open_or_create_db(
     Ok(conn)
 }
 
+/// Return database to a clean slate.
+pub fn reset_db(description: &DatabaseDescription, identifier: Option<&str>) -> Result<()> {
+    let db_path = if let Some(id) = identifier {
+        db_path(&format!("{}_{}", id, description.name))
+    } else {
+        db_path(description.name)
+    }?;
+    if !db_path.exists() {
+        return Ok(());
+    }
+    log(
+        format!(
+            "Resetting {} database in {}",
+            description.name,
+            db_path.display()
+        ),
+        crate::INFO,
+    );
+    std::fs::remove_file(&db_path)?;
+    Ok(())
+}
+
 impl ToSql for Envelope {
     fn to_sql(&self) -> rusqlite::Result<ToSqlOutput> {
         let v: Vec<u8> = bincode::serialize(self).map_err(|e| {