Merge branch 'caldav'

1 files changed, 206 insertions, 0 deletions

diff --git a/aero-collections/src/mail/namespace.rs b/aero-collections/src/mail/namespace.rs
new file mode 100644
index 0000000..0f1db7d
--- /dev/null
+++ b/aero-collections/src/mail/namespace.rs
@@ -0,0 +1,206 @@
+use std::collections::BTreeMap;
+
+use anyhow::{bail, Result};
+use serde::{Deserialize, Serialize};
+
+use aero_bayou::timestamp::now_msec;
+
+use crate::mail::uidindex::ImapUidvalidity;
+use crate::unique_ident::{gen_ident, UniqueIdent};
+
+pub const MAILBOX_HIERARCHY_DELIMITER: char = '.';
+
+/// INBOX is the only mailbox that must always exist.
+/// It is created automatically when the account is created.
+/// IMAP allows the user to rename INBOX to something else,
+/// in this case all messages from INBOX are moved to a mailbox
+/// with the new name and the INBOX mailbox still exists and is empty.
+/// In our implementation, we indeed move the underlying mailbox
+/// to the new name (i.e. the new name has the same id as the previous
+/// INBOX), and we create a new empty mailbox for INBOX.
+pub const INBOX: &str = "INBOX";
+
+/// For convenience purpose, we also create some special mailbox
+/// that are described in RFC6154 SPECIAL-USE
+/// @FIXME maybe it should be a configuration parameter
+/// @FIXME maybe we should have a per-mailbox flag mechanism, either an enum or a string, so we
+/// track which mailbox is used for what.
+/// @FIXME Junk could be useful but we don't have any antispam solution yet so...
+/// @FIXME IMAP supports virtual mailbox. \All or \Flagged are intended to be virtual mailboxes.
+/// \Trash might be one, or not one. I don't know what we should do there.
+pub const DRAFTS: &str = "Drafts";
+pub const ARCHIVE: &str = "Archive";
+pub const SENT: &str = "Sent";
+pub const TRASH: &str = "Trash";
+
+pub(crate) const MAILBOX_LIST_PK: &str = "mailboxes";
+pub(crate) const MAILBOX_LIST_SK: &str = "list";
+
+// ---- User's mailbox list (serialized in K2V) ----
+
+#[derive(Serialize, Deserialize)]
+pub(crate) struct MailboxList(BTreeMap<String, MailboxListEntry>);
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug)]
+pub(crate) struct MailboxListEntry {
+    id_lww: (u64, Option<UniqueIdent>),
+    uidvalidity: ImapUidvalidity,
+}
+
+impl MailboxListEntry {
+    fn merge(&mut self, other: &Self) {
+        // Simple CRDT merge rule
+        if other.id_lww.0 > self.id_lww.0
+            || (other.id_lww.0 == self.id_lww.0 && other.id_lww.1 > self.id_lww.1)
+        {
+            self.id_lww = other.id_lww;
+        }
+        self.uidvalidity = std::cmp::max(self.uidvalidity, other.uidvalidity);
+    }
+}
+
+impl MailboxList {
+    pub(crate) fn new() -> Self {
+        Self(BTreeMap::new())
+    }
+
+    pub(crate) fn merge(&mut self, list2: Self) {
+        for (k, v) in list2.0.into_iter() {
+            if let Some(e) = self.0.get_mut(&k) {
+                e.merge(&v);
+            } else {
+                self.0.insert(k, v);
+            }
+        }
+    }
+
+    pub(crate) fn existing_mailbox_names(&self) -> Vec<String> {
+        self.0
+            .iter()
+            .filter(|(_, v)| v.id_lww.1.is_some())
+            .map(|(k, _)| k.to_string())
+            .collect()
+    }
+
+    pub(crate) fn has_mailbox(&self, name: &str) -> bool {
+        matches!(
+            self.0.get(name),
+            Some(MailboxListEntry {
+                id_lww: (_, Some(_)),
+                ..
+            })
+        )
+    }
+
+    pub(crate) fn get_mailbox(&self, name: &str) -> Option<(ImapUidvalidity, Option<UniqueIdent>)> {
+        self.0.get(name).map(
+            |MailboxListEntry {
+                 id_lww: (_, mailbox_id),
+                 uidvalidity,
+             }| (*uidvalidity, *mailbox_id),
+        )
+    }
+
+    /// Ensures mailbox `name` maps to id `id`.
+    /// If it already mapped to that, returns None.
+    /// If a change had to be done, returns Some(new uidvalidity in mailbox).
+    pub(crate) fn set_mailbox(
+        &mut self,
+        name: &str,
+        id: Option<UniqueIdent>,
+    ) -> Option<ImapUidvalidity> {
+        let (ts, id, uidvalidity) = match self.0.get_mut(name) {
+            None => {
+                if id.is_none() {
+                    return None;
+                } else {
+                    (now_msec(), id, ImapUidvalidity::new(1).unwrap())
+                }
+            }
+            Some(MailboxListEntry {
+                id_lww,
+                uidvalidity,
+            }) => {
+                if id_lww.1 == id {
+                    return None;
+                } else {
+                    (
+                        std::cmp::max(id_lww.0 + 1, now_msec()),
+                        id,
+                        ImapUidvalidity::new(uidvalidity.get() + 1).unwrap(),
+                    )
+                }
+            }
+        };
+
+        self.0.insert(
+            name.into(),
+            MailboxListEntry {
+                id_lww: (ts, id),
+                uidvalidity,
+            },
+        );
+        Some(uidvalidity)
+    }
+
+    pub(crate) fn update_uidvalidity(&mut self, name: &str, new_uidvalidity: ImapUidvalidity) {
+        match self.0.get_mut(name) {
+            None => {
+                self.0.insert(
+                    name.into(),
+                    MailboxListEntry {
+                        id_lww: (now_msec(), None),
+                        uidvalidity: new_uidvalidity,
+                    },
+                );
+            }
+            Some(MailboxListEntry { uidvalidity, .. }) => {
+                *uidvalidity = std::cmp::max(*uidvalidity, new_uidvalidity);
+            }
+        }
+    }
+
+    pub(crate) fn create_mailbox(&mut self, name: &str) -> CreatedMailbox {
+        if let Some(MailboxListEntry {
+            id_lww: (_, Some(id)),
+            uidvalidity,
+        }) = self.0.get(name)
+        {
+            return CreatedMailbox::Existed(*id, *uidvalidity);
+        }
+
+        let id = gen_ident();
+        let uidvalidity = self.set_mailbox(name, Some(id)).unwrap();
+        CreatedMailbox::Created(id, uidvalidity)
+    }
+
+    pub(crate) fn rename_mailbox(&mut self, old_name: &str, new_name: &str) -> Result<()> {
+        if let Some((uidvalidity, Some(mbid))) = self.get_mailbox(old_name) {
+            if self.has_mailbox(new_name) {
+                bail!(
+                    "Cannot rename {} into {}: {} already exists",
+                    old_name,
+                    new_name,
+                    new_name
+                );
+            }
+
+            self.set_mailbox(old_name, None);
+            self.set_mailbox(new_name, Some(mbid));
+            self.update_uidvalidity(new_name, uidvalidity);
+            Ok(())
+        } else {
+            bail!(
+                "Cannot rename {} into {}: {} doesn't exist",
+                old_name,
+                new_name,
+                old_name
+            );
+        }
+    }
+}
+
+pub(crate) enum CreatedMailbox {
+    Created(UniqueIdent, ImapUidvalidity),
+    Existed(UniqueIdent, ImapUidvalidity),
+}