use std::collections::{BTreeMap, HashMap};
use std::sync::{Arc, Weak};
use anyhow::{anyhow, bail, Result};
use k2v_client::{CausalityToken, K2vClient, K2vValue};
use lazy_static::lazy_static;
use serde::{Deserialize, Serialize};
use tokio::sync::watch;
use crate::cryptoblob::{open_deserialize, seal_serialize};
use crate::login::{Credentials, StorageCredentials};
use crate::mail::incoming::incoming_mail_watch_process;
use crate::mail::mailbox::Mailbox;
use crate::mail::uidindex::ImapUidvalidity;
use crate::mail::unique_ident::{gen_ident, UniqueIdent};
use crate::time::now_msec;
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";
const MAILBOX_LIST_PK: &str = "mailboxes";
const MAILBOX_LIST_SK: &str = "list";
use crate::storage::*;
pub struct User {
pub username: String,
pub creds: Credentials,
pub k2v: K2vClient,
pub mailboxes: std::sync::Mutex<HashMap<UniqueIdent, Weak<Mailbox>>>,
tx_inbox_id: watch::Sender<Option<(UniqueIdent, ImapUidvalidity)>>,
}
impl User {
pub async fn new(username: String, creds: Credentials) -> Result<Arc<Self>> {
let cache_key = (username.clone(), creds.storage.clone());
{
let cache = USER_CACHE.lock().unwrap();
if let Some(u) = cache.get(&cache_key).and_then(Weak::upgrade) {
return Ok(u);
}
}
let user = Self::open(username, creds).await?;
let mut cache = USER_CACHE.lock().unwrap();
if let Some(concurrent_user) = cache.get(&cache_key).and_then(Weak::upgrade) {
drop(user);
Ok(concurrent_user)
} else {
cache.insert(cache_key, Arc::downgrade(&user));
Ok(user)
}
}
/// Lists user's available mailboxes
pub async fn list_mailboxes(&self) -> Result<Vec<String>> {
let (list, _ct) = self.load_mailbox_list().await?;
Ok(list.existing_mailbox_names())
}
/// Opens an existing mailbox given its IMAP name.
pub async fn open_mailbox(&self, name: &str) -> Result<Option<Arc<Mailbox>>> {
let (mut list, ct) = self.load_mailbox_list().await?;
eprintln!("List of mailboxes:");
for ent in list.0.iter() {
eprintln!(" - {:?}", ent);
}
if let Some((uidvalidity, Some(mbid))) = list.get_mailbox(name) {
let mb = self.open_mailbox_by_id(mbid, uidvalidity).await?;
let mb_uidvalidity = mb.current_uid_index().await.uidvalidity;
if mb_uidvalidity > uidvalidity {
list.update_uidvalidity(name, mb_uidvalidity);
self.save_mailbox_list(&list, ct).await?;
}
Ok(Some(mb))
} else {
Ok(None)
}
}
/// Check whether mailbox exists
pub async fn has_mailbox(&self, name: &str) -> Result<bool> {
let (list, _ct) = self.load_mailbox_list().await?;
Ok(list.has_mailbox(name))
}
/// Creates a new mailbox in the user's IMAP namespace.
pub async fn create_mailbox(&self, name: &str) -> Result<()> {
if name.ends_with(MAILBOX_HIERARCHY_DELIMITER) {
bail!("Invalid mailbox name: {}", name);
}
let (mut list, ct) = self.load_mailbox_list().await?;
match list.create_mailbox(name) {
CreatedMailbox::Created(_, _) => {
self.save_mailbox_list(&list, ct).await?;
Ok(())
}
CreatedMailbox::Existed(_, _) => Err(anyhow!("Mailbox {} already exists", name)),
}
}
/// Deletes a mailbox in the user's IMAP namespace.
pub async fn delete_mailbox(&self, name: &str) -> Result<()> {
if name == INBOX {
bail!("Cannot delete INBOX");
}
let (mut list, ct) = self.load_mailbox_list().await?;
if list.has_mailbox(name) {
// TODO: actually delete mailbox contents
list.set_mailbox(name, None);
self.save_mailbox_list(&list, ct).await?;
Ok(())
} else {
bail!("Mailbox {} does not exist", name);
}
}
/// Renames a mailbox in the user's IMAP namespace.
pub async fn rename_mailbox(&self, old_name: &str, new_name: &str) -> Result<()> {
let (mut list, ct) = self.load_mailbox_list().await?;
if old_name.ends_with(MAILBOX_HIERARCHY_DELIMITER) {
bail!("Invalid mailbox name: {}", old_name);
}
if new_name.ends_with(MAILBOX_HIERARCHY_DELIMITER) {
bail!("Invalid mailbox name: {}", new_name);
}
if old_name == INBOX {
list.rename_mailbox(old_name, new_name)?;
if !self.ensure_inbox_exists(&mut list, &ct).await? {
self.save_mailbox_list(&list, ct).await?;
}
} else {
let names = list.existing_mailbox_names();
let old_name_w_delim = format!("{}{}", old_name, MAILBOX_HIERARCHY_DELIMITER);
let new_name_w_delim = format!("{}{}", new_name, MAILBOX_HIERARCHY_DELIMITER);
if names
.iter()
.any(|x| x == new_name || x.starts_with(&new_name_w_delim))
{
bail!("Mailbox {} already exists", new_name);
}
for name in names.iter() {
if name == old_name {
list.rename_mailbox(name, new_name)?;
} else if let Some(tail) = name.strip_prefix(&old_name_w_delim) {
let nnew = format!("{}{}", new_name_w_delim, tail);
list.rename_mailbox(name, &nnew)?;
}
}
self.save_mailbox_list(&list, ct).await?;
}
Ok(())
}
// ---- Internal user & mailbox management ----
async fn open(username: String, creds: Credentials) -> Result<Arc<Self>> {
let k2v = creds.k2v_client()?;
let (tx_inbox_id, rx_inbox_id) = watch::channel(None);
let user = Arc::new(Self {
username,
creds: creds.clone(),
k2v,
tx_inbox_id,
mailboxes: std::sync::Mutex::new(HashMap::new()),
});
// Ensure INBOX exists (done inside load_mailbox_list)
user.load_mailbox_list().await?;
tokio::spawn(incoming_mail_watch_process(
Arc::downgrade(&user),
user.creds.clone(),
rx_inbox_id,
));
Ok(user)
}
pub(super) async fn open_mailbox_by_id(
&self,
id: UniqueIdent,
min_uidvalidity: ImapUidvalidity,
) -> Result<Arc<Mailbox>> {
{
let cache = self.mailboxes.lock().unwrap();
if let Some(mb) = cache.get(&id).and_then(Weak::upgrade) {
return Ok(mb);
}
}
let mb = Arc::new(Mailbox::open(&self.creds, id, min_uidvalidity).await?);
let mut cache = self.mailboxes.lock().unwrap();
if let Some(concurrent_mb) = cache.get(&id).and_then(Weak::upgrade) {
drop(mb); // we worked for nothing but at least we didn't starve someone else
Ok(concurrent_mb)
} else {
cache.insert(id, Arc::downgrade(&mb));
Ok(mb)
}
}
// ---- Mailbox list management ----
async fn load_mailbox_list(&self) -> Result<(MailboxList, Option<CausalityToken>)> {
let (mut list, ct) = match self.k2v.read_item(MAILBOX_LIST_PK, MAILBOX_LIST_SK).await {
Err(k2v_client::Error::NotFound) => (MailboxList::new(), None),
Err(e) => return Err(e.into()),
Ok(cv) => {
let mut list = MailboxList::new();
for v in cv.value {
if let K2vValue::Value(vbytes) = v {
let list2 =
open_deserialize::<MailboxList>(&vbytes, &self.creds.keys.master)?;
list.merge(list2);
}
}
(list, Some(cv.causality))
}
};
self.ensure_inbox_exists(&mut list, &ct).await?;
Ok((list, ct))
}
async fn ensure_inbox_exists(
&self,
list: &mut MailboxList,
ct: &Option<CausalityToken>,
) -> Result<bool> {
// If INBOX doesn't exist, create a new mailbox with that name
// and save new mailbox list.
// Also, ensure that the mpsc::watch that keeps track of the
// inbox id is up-to-date.
let saved;
let (inbox_id, inbox_uidvalidity) = match list.create_mailbox(INBOX) {
CreatedMailbox::Created(i, v) => {
self.save_mailbox_list(list, ct.clone()).await?;
saved = true;
(i, v)
}
CreatedMailbox::Existed(i, v) => {
saved = false;
(i, v)
}
};
let inbox_id = Some((inbox_id, inbox_uidvalidity));
if *self.tx_inbox_id.borrow() != inbox_id {
self.tx_inbox_id.send(inbox_id).unwrap();
}
Ok(saved)
}
async fn save_mailbox_list(
&self,
list: &MailboxList,
ct: Option<CausalityToken>,
) -> Result<()> {
let list_blob = seal_serialize(list, &self.creds.keys.master)?;
self.k2v
.insert_item(MAILBOX_LIST_PK, MAILBOX_LIST_SK, list_blob, ct)
.await?;
Ok(())
}
}
// ---- User's mailbox list (serialized in K2V) ----
#[derive(Serialize, Deserialize)]
struct MailboxList(BTreeMap<String, MailboxListEntry>);
#[derive(Serialize, Deserialize, Clone, Copy, Debug)]
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 {
fn new() -> Self {
Self(BTreeMap::new())
}
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);
}
}
}
fn existing_mailbox_names(&self) -> Vec<String> {
self.0
.iter()
.filter(|(_, v)| v.id_lww.1.is_some())
.map(|(k, _)| k.to_string())
.collect()
}
fn has_mailbox(&self, name: &str) -> bool {
matches!(
self.0.get(name),
Some(MailboxListEntry {
id_lww: (_, Some(_)),
..
})
)
}
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).
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)
}
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);
}
}
}
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)
}
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
);
}
}
}
enum CreatedMailbox {
Created(UniqueIdent, ImapUidvalidity),
Existed(UniqueIdent, ImapUidvalidity),
}
// ---- User cache ----
lazy_static! {
static ref USER_CACHE: std::sync::Mutex<HashMap<(String, StorageCredentials), Weak<User>>> =
std::sync::Mutex::new(HashMap::new());
}