melib/imap: reset imap cache on init error

melib/src/backends/imap.rs

@@ -33,7 +33,7 @@ pub use connection::*;
 mod watch;
 pub use watch::*;
 mod cache;
-use cache::ModSequence;
+use cache::{ImapCacheReset, ModSequence};
 pub mod managesieve;
 mod untagged;
 
@@ -301,14 +301,26 @@ impl MailBackend for ImapType {
             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 {}",
+                        "Could not initialize cache for IMAP account {}. Resetting database.",
                         self.uid_store.account_name
                     )
                 }) {
                     Ok(v) => Some(v),
                     Err(err) => {
                         (self.uid_store.event_consumer)(self.uid_store.account_hash, err.into());
-                        None
+                        match cache::Sqlite3Cache::reset_db(&self.uid_store)
+                            .and_then(|()| cache::Sqlite3Cache::get(self.uid_store.clone()))
+                            .chain_err_summary(|| "Could not reset IMAP cache database.")
+                        {
+                            Ok(v) => Some(v),
+                            Err(err) => {
+                                (self.uid_store.event_consumer)(
+                                    self.uid_store.account_hash,
+                                    err.into(),
+                                );
+                                None
+                            }
+                        }
                     }
                 }
             } else {

melib/src/backends/imap/cache.rs

@@ -93,6 +93,12 @@ pub trait ImapCache: Send + core::fmt::Debug {
     ) -> Result<Option<Vec<u8>>>;
 }
 
+pub trait ImapCacheReset: Send + core::fmt::Debug {
+    fn reset_db(uid_store: &UIDStore) -> Result<()>
+    where
+        Self: Sized;
+}
+
 #[cfg(feature = "sqlite3")]
 pub use sqlite3_m::*;
 
@@ -185,9 +191,15 @@ mod sqlite3_m {
         }
     }
 
+    impl ImapCacheReset for Sqlite3Cache {
+        fn reset_db(uid_store: &UIDStore) -> Result<()> {
+            sqlite3::reset_db(&DB_DESCRIPTION, Some(uid_store.account_name.as_str()))
+        }
+    }
+
     impl ImapCache for Sqlite3Cache {
         fn reset(&mut self) -> Result<()> {
-            sqlite3::reset_db(&DB_DESCRIPTION, Some(self.uid_store.account_name.as_str()))
+            Sqlite3Cache::reset_db(&self.uid_store)
         }
 
         fn mailbox_state(&mut self, mailbox_hash: MailboxHash) -> Result<Option<()>> {
@@ -687,9 +699,15 @@ mod default_m {
         }
     }
 
+    impl ImapCacheReset for DefaultCache {
+        fn reset_db(uid_store: &UIDStore) -> Result<()> {
+            Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
+        }
+    }
+
     impl ImapCache for DefaultCache {
         fn reset(&mut self) -> Result<()> {
-            Err(MeliError::new("melib is not built with any imap cache").set_kind(ErrorKind::Bug))
+            DefaultCache::reset_db(&self.uid_store)
         }
 
         fn mailbox_state(&mut self, _mailbox_hash: MailboxHash) -> Result<Option<()>> {