From b2ff359eb70d294532c9ef2a3884951608576f73 Mon Sep 17 00:00:00 2001
From: Manos Pitsidianakis <el13635@mail.ntua.gr>
Date: Sat, 3 Sep 2022 23:44:39 +0300
Subject: [PATCH] melib/imap: add support for CHILDREN extesion RFC 3348

---
 melib/src/backends/imap.rs                 |  1 +
 melib/src/backends/imap/mailbox.rs         | 12 ++++++++++++
 melib/src/backends/imap/protocol_parser.rs |  5 +++++
 3 files changed, 18 insertions(+)

diff --git a/melib/src/backends/imap.rs b/melib/src/backends/imap.rs
index 8e27d470..29812921 100644
--- a/melib/src/backends/imap.rs
+++ b/melib/src/backends/imap.rs
@@ -66,6 +66,7 @@ pub type MessageSequenceNumber = ImapNum;
 
 pub static SUPPORTED_CAPABILITIES: &[&str] = &[
     "AUTH=OAUTH2",
+    "CHILDREN",
     #[cfg(feature = "deflate_compression")]
     "COMPRESS=DEFLATE",
     "CONDSTORE",
diff --git a/melib/src/backends/imap/mailbox.rs b/melib/src/backends/imap/mailbox.rs
index baa918ca..00f5ce0f 100644
--- a/melib/src/backends/imap/mailbox.rs
+++ b/melib/src/backends/imap/mailbox.rs
@@ -33,6 +33,7 @@ pub struct ImapMailbox {
     pub path: String,
     pub name: String,
     pub parent: Option<MailboxHash>,
+    pub has_children: bool,
     pub children: Vec<MailboxHash>,
     pub separator: u8,
     pub usage: Arc<RwLock<SpecialUsageMailbox>>,
@@ -47,6 +48,12 @@ pub struct ImapMailbox {
 }
 
 impl ImapMailbox {
+    pub fn set_has_children(&mut self, has_children: bool) -> &mut Self {
+        self.has_children = has_children;
+
+        self
+    }
+
     pub fn imap_path(&self) -> &str {
         &self.imap_path
     }
@@ -88,6 +95,9 @@ impl BackendMailbox for ImapMailbox {
     }
 
     fn children(&self) -> &[MailboxHash] {
+        if !self.has_children {
+            return &[];
+        }
         &self.children
     }
 
@@ -106,9 +116,11 @@ impl BackendMailbox for ImapMailbox {
     fn permissions(&self) -> MailboxPermissions {
         *self.permissions.lock().unwrap()
     }
+
     fn is_subscribed(&self) -> bool {
         self.is_subscribed
     }
+
     fn set_is_subscribed(&mut self, new_val: bool) -> Result<()> {
         self.is_subscribed = new_val;
         Ok(())
diff --git a/melib/src/backends/imap/protocol_parser.rs b/melib/src/backends/imap/protocol_parser.rs
index ab78b28b..3a865725 100644
--- a/melib/src/backends/imap/protocol_parser.rs
+++ b/melib/src/backends/imap/protocol_parser.rs
@@ -449,6 +449,7 @@ pub fn list_mailbox_result(input: &[u8]) -> IResult<&[u8], ImapMailbox> {
         ({
             let separator: u8 = separator[0];
             let mut f = ImapMailbox::default();
+            f.has_children = true;
             f.no_select = false;
             f.is_subscribed = false;
 
@@ -475,6 +476,10 @@ pub fn list_mailbox_result(input: &[u8]) -> IResult<&[u8], ImapMailbox> {
                     let _ = f.set_special_usage(SpecialUsageMailbox::Flagged);
                 } else if p.eq_ignore_ascii_case(b"\\Archive") {
                     let _ = f.set_special_usage(SpecialUsageMailbox::Archive);
+                } else if p.eq_ignore_ascii_case(b"\\HasChildren") {
+                    f.has_children = true;
+                } else if p.eq_ignore_ascii_case(b"\\HasNoChildren") {
+                    f.has_children = false;
                 }
             }
             f.imap_path = path.to_string();