Merge branch 'caldav'

1 files changed, 478 insertions, 0 deletions

diff --git a/aero-proto/src/imap/search.rs b/aero-proto/src/imap/search.rs
new file mode 100644
index 0000000..3634a3a
--- /dev/null
+++ b/aero-proto/src/imap/search.rs
@@ -0,0 +1,478 @@
+use std::num::{NonZeroU32, NonZeroU64};
+
+use imap_codec::imap_types::core::Vec1;
+use imap_codec::imap_types::search::{MetadataItemSearch, SearchKey};
+use imap_codec::imap_types::sequence::{SeqOrUid, Sequence, SequenceSet};
+
+use aero_collections::mail::query::QueryScope;
+
+use crate::imap::index::MailIndex;
+use crate::imap::mail_view::MailView;
+
+pub enum SeqType {
+    Undefined,
+    NonUid,
+    Uid,
+}
+impl SeqType {
+    pub fn is_uid(&self) -> bool {
+        matches!(self, Self::Uid)
+    }
+}
+
+pub struct Criteria<'a>(pub &'a SearchKey<'a>);
+impl<'a> Criteria<'a> {
+    /// Returns a set of email identifiers that is greater or equal
+    /// to the set of emails to return
+    pub fn to_sequence_set(&self) -> (SequenceSet, SeqType) {
+        match self.0 {
+            SearchKey::All => (sequence_set_all(), SeqType::Undefined),
+            SearchKey::SequenceSet(seq_set) => (seq_set.clone(), SeqType::NonUid),
+            SearchKey::Uid(seq_set) => (seq_set.clone(), SeqType::Uid),
+            SearchKey::Not(_inner) => {
+                tracing::debug!(
+                    "using NOT in a search request is slow: it selects all identifiers"
+                );
+                (sequence_set_all(), SeqType::Undefined)
+            }
+            SearchKey::Or(left, right) => {
+                tracing::debug!("using OR in a search request is slow: no deduplication is done");
+                let (base, base_seqtype) = Self(&left).to_sequence_set();
+                let (ext, ext_seqtype) = Self(&right).to_sequence_set();
+
+                // Check if we have a UID/ID conflict in fetching: now we don't know how to handle them
+                match (base_seqtype, ext_seqtype) {
+                    (SeqType::Uid, SeqType::NonUid) | (SeqType::NonUid, SeqType::Uid) => {
+                        (sequence_set_all(), SeqType::Undefined)
+                    }
+                    (SeqType::Undefined, x) | (x, _) => {
+                        let mut new_vec = base.0.into_inner();
+                        new_vec.extend_from_slice(ext.0.as_ref());
+                        let seq = SequenceSet(
+                            Vec1::try_from(new_vec)
+                                .expect("merging non empty vec lead to non empty vec"),
+                        );
+                        (seq, x)
+                    }
+                }
+            }
+            SearchKey::And(search_list) => {
+                tracing::debug!(
+                    "using AND in a search request is slow: no intersection is performed"
+                );
+                // As we perform no intersection, we don't care if we mix uid or id.
+                // We only keep the smallest range, being it ID or UID, depending of
+                // which one has the less items. This is an approximation as UID ranges
+                // can have holes while ID ones can't.
+                search_list
+                    .as_ref()
+                    .iter()
+                    .map(|crit| Self(&crit).to_sequence_set())
+                    .min_by(|(x, _), (y, _)| {
+                        let x_size = approx_sequence_set_size(x);
+                        let y_size = approx_sequence_set_size(y);
+                        x_size.cmp(&y_size)
+                    })
+                    .unwrap_or((sequence_set_all(), SeqType::Undefined))
+            }
+            _ => (sequence_set_all(), SeqType::Undefined),
+        }
+    }
+
+    /// Not really clever as we can have cases where we filter out
+    /// the email before needing to inspect its meta.
+    /// But for now we are seeking the most basic/stupid algorithm.
+    pub fn query_scope(&self) -> QueryScope {
+        use SearchKey::*;
+        match self.0 {
+            // Combinators
+            And(and_list) => and_list
+                .as_ref()
+                .iter()
+                .fold(QueryScope::Index, |prev, sk| {
+                    prev.union(&Criteria(sk).query_scope())
+                }),
+            Not(inner) => Criteria(inner).query_scope(),
+            Or(left, right) => Criteria(left)
+                .query_scope()
+                .union(&Criteria(right).query_scope()),
+            All => QueryScope::Index,
+
+            // IMF Headers
+            Bcc(_) | Cc(_) | From(_) | Header(..) | SentBefore(_) | SentOn(_) | SentSince(_)
+            | Subject(_) | To(_) => QueryScope::Partial,
+            // Internal Date is also stored in MailMeta
+            Before(_) | On(_) | Since(_) => QueryScope::Partial,
+            // Message size is also stored in MailMeta
+            Larger(_) | Smaller(_) => QueryScope::Partial,
+            // Text and Body require that we fetch the full content!
+            Text(_) | Body(_) => QueryScope::Full,
+
+            _ => QueryScope::Index,
+        }
+    }
+
+    pub fn is_modseq(&self) -> bool {
+        use SearchKey::*;
+        match self.0 {
+            And(and_list) => and_list
+                .as_ref()
+                .iter()
+                .any(|child| Criteria(child).is_modseq()),
+            Or(left, right) => Criteria(left).is_modseq() || Criteria(right).is_modseq(),
+            Not(child) => Criteria(child).is_modseq(),
+            ModSeq { .. } => true,
+            _ => false,
+        }
+    }
+
+    /// Returns emails that we now for sure we want to keep
+    /// but also a second list of emails we need to investigate further by
+    /// fetching some remote data
+    pub fn filter_on_idx<'b>(
+        &self,
+        midx_list: &[&'b MailIndex<'b>],
+    ) -> (Vec<&'b MailIndex<'b>>, Vec<&'b MailIndex<'b>>) {
+        let (p1, p2): (Vec<_>, Vec<_>) = midx_list
+            .iter()
+            .map(|x| (x, self.is_keep_on_idx(x)))
+            .filter(|(_midx, decision)| decision.is_keep())
+            .map(|(midx, decision)| (*midx, decision))
+            .partition(|(_midx, decision)| matches!(decision, PartialDecision::Keep));
+
+        let to_keep = p1.into_iter().map(|(v, _)| v).collect();
+        let to_fetch = p2.into_iter().map(|(v, _)| v).collect();
+        (to_keep, to_fetch)
+    }
+
+    // ----
+
+    /// Here we are doing a partial filtering: we do not have access
+    /// to the headers or to the body, so every time we encounter a rule
+    /// based on them, we need to keep it.
+    ///
+    /// @TODO Could be optimized on a per-email basis by also returning the QueryScope
+    /// when more information is needed!
+    fn is_keep_on_idx(&self, midx: &MailIndex) -> PartialDecision {
+        use SearchKey::*;
+        match self.0 {
+            // Combinator logic
+            And(expr_list) => expr_list
+                .as_ref()
+                .iter()
+                .fold(PartialDecision::Keep, |acc, cur| {
+                    acc.and(&Criteria(cur).is_keep_on_idx(midx))
+                }),
+            Or(left, right) => {
+                let left_decision = Criteria(left).is_keep_on_idx(midx);
+                let right_decision = Criteria(right).is_keep_on_idx(midx);
+                left_decision.or(&right_decision)
+            }
+            Not(expr) => Criteria(expr).is_keep_on_idx(midx).not(),
+            All => PartialDecision::Keep,
+
+            // Sequence logic
+            maybe_seq if is_sk_seq(maybe_seq) => is_keep_seq(maybe_seq, midx).into(),
+            maybe_flag if is_sk_flag(maybe_flag) => is_keep_flag(maybe_flag, midx).into(),
+            ModSeq {
+                metadata_item,
+                modseq,
+            } => is_keep_modseq(metadata_item, modseq, midx).into(),
+
+            // All the stuff we can't evaluate yet
+            Bcc(_) | Cc(_) | From(_) | Header(..) | SentBefore(_) | SentOn(_) | SentSince(_)
+            | Subject(_) | To(_) | Before(_) | On(_) | Since(_) | Larger(_) | Smaller(_)
+            | Text(_) | Body(_) => PartialDecision::Postpone,
+
+            unknown => {
+                tracing::error!("Unknown filter {:?}", unknown);
+                PartialDecision::Discard
+            }
+        }
+    }
+
+    /// @TODO we re-eveluate twice the same logic. The correct way would be, on each pass,
+    /// to simplify the searck query, by removing the elements that were already checked.
+    /// For example if we have AND(OR(seqid(X), body(Y)), body(X)), we can't keep for sure
+    /// the email, as body(x) might be false. So we need to check it. But as seqid(x) is true,
+    /// we could simplify the request to just body(x) and truncate the first OR. Today, we are
+    /// not doing that, and thus we reevaluate everything.
+    pub fn is_keep_on_query(&self, mail_view: &MailView) -> bool {
+        use SearchKey::*;
+        match self.0 {
+            // Combinator logic
+            And(expr_list) => expr_list
+                .as_ref()
+                .iter()
+                .all(|cur| Criteria(cur).is_keep_on_query(mail_view)),
+            Or(left, right) => {
+                Criteria(left).is_keep_on_query(mail_view)
+                    || Criteria(right).is_keep_on_query(mail_view)
+            }
+            Not(expr) => !Criteria(expr).is_keep_on_query(mail_view),
+            All => true,
+
+            //@FIXME Reevaluating our previous logic...
+            maybe_seq if is_sk_seq(maybe_seq) => is_keep_seq(maybe_seq, &mail_view.in_idx),
+            maybe_flag if is_sk_flag(maybe_flag) => is_keep_flag(maybe_flag, &mail_view.in_idx),
+            ModSeq {
+                metadata_item,
+                modseq,
+            } => is_keep_modseq(metadata_item, modseq, &mail_view.in_idx).into(),
+
+            // Filter on mail meta
+            Before(search_naive) => match mail_view.stored_naive_date() {
+                Ok(msg_naive) => &msg_naive < search_naive.as_ref(),
+                _ => false,
+            },
+            On(search_naive) => match mail_view.stored_naive_date() {
+                Ok(msg_naive) => &msg_naive == search_naive.as_ref(),
+                _ => false,
+            },
+            Since(search_naive) => match mail_view.stored_naive_date() {
+                Ok(msg_naive) => &msg_naive > search_naive.as_ref(),
+                _ => false,
+            },
+
+            // Message size is also stored in MailMeta
+            Larger(size_ref) => {
+                mail_view
+                    .query_result
+                    .metadata()
+                    .expect("metadata were fetched")
+                    .rfc822_size
+                    > *size_ref as usize
+            }
+            Smaller(size_ref) => {
+                mail_view
+                    .query_result
+                    .metadata()
+                    .expect("metadata were fetched")
+                    .rfc822_size
+                    < *size_ref as usize
+            }
+
+            // Filter on well-known headers
+            Bcc(txt) => mail_view.is_header_contains_pattern(&b"bcc"[..], txt.as_ref()),
+            Cc(txt) => mail_view.is_header_contains_pattern(&b"cc"[..], txt.as_ref()),
+            From(txt) => mail_view.is_header_contains_pattern(&b"from"[..], txt.as_ref()),
+            Subject(txt) => mail_view.is_header_contains_pattern(&b"subject"[..], txt.as_ref()),
+            To(txt) => mail_view.is_header_contains_pattern(&b"to"[..], txt.as_ref()),
+            Header(hdr, txt) => mail_view.is_header_contains_pattern(hdr.as_ref(), txt.as_ref()),
+
+            // Filter on Date header
+            SentBefore(search_naive) => mail_view
+                .imf()
+                .map(|imf| imf.naive_date().ok())
+                .flatten()
+                .map(|msg_naive| &msg_naive < search_naive.as_ref())
+                .unwrap_or(false),
+            SentOn(search_naive) => mail_view
+                .imf()
+                .map(|imf| imf.naive_date().ok())
+                .flatten()
+                .map(|msg_naive| &msg_naive == search_naive.as_ref())
+                .unwrap_or(false),
+            SentSince(search_naive) => mail_view
+                .imf()
+                .map(|imf| imf.naive_date().ok())
+                .flatten()
+                .map(|msg_naive| &msg_naive > search_naive.as_ref())
+                .unwrap_or(false),
+
+            // Filter on the full content of the email
+            Text(txt) => mail_view
+                .content
+                .as_msg()
+                .map(|msg| {
+                    msg.raw_part
+                        .windows(txt.as_ref().len())
+                        .any(|win| win == txt.as_ref())
+                })
+                .unwrap_or(false),
+            Body(txt) => mail_view
+                .content
+                .as_msg()
+                .map(|msg| {
+                    msg.raw_body
+                        .windows(txt.as_ref().len())
+                        .any(|win| win == txt.as_ref())
+                })
+                .unwrap_or(false),
+
+            unknown => {
+                tracing::error!("Unknown filter {:?}", unknown);
+                false
+            }
+        }
+    }
+}
+
+// ---- Sequence things ----
+fn sequence_set_all() -> SequenceSet {
+    SequenceSet::from(Sequence::Range(
+        SeqOrUid::Value(NonZeroU32::MIN),
+        SeqOrUid::Asterisk,
+    ))
+}
+
+// This is wrong as sequences can overlap
+fn approx_sequence_set_size(seq_set: &SequenceSet) -> u64 {
+    seq_set.0.as_ref().iter().fold(0u64, |acc, seq| {
+        acc.saturating_add(approx_sequence_size(seq))
+    })
+}
+
+// This is wrong as sequence UID can have holes,
+// as we don't know the number of messages in the mailbox also
+// we gave to guess
+fn approx_sequence_size(seq: &Sequence) -> u64 {
+    match seq {
+        Sequence::Single(_) => 1,
+        Sequence::Range(SeqOrUid::Asterisk, _) | Sequence::Range(_, SeqOrUid::Asterisk) => u64::MAX,
+        Sequence::Range(SeqOrUid::Value(x1), SeqOrUid::Value(x2)) => {
+            let x2 = x2.get() as i64;
+            let x1 = x1.get() as i64;
+            (x2 - x1).abs().try_into().unwrap_or(1)
+        }
+    }
+}
+
+// --- Partial decision things ----
+
+enum PartialDecision {
+    Keep,
+    Discard,
+    Postpone,
+}
+impl From<bool> for PartialDecision {
+    fn from(x: bool) -> Self {
+        match x {
+            true => PartialDecision::Keep,
+            _ => PartialDecision::Discard,
+        }
+    }
+}
+impl PartialDecision {
+    fn not(&self) -> Self {
+        match self {
+            Self::Keep => Self::Discard,
+            Self::Discard => Self::Keep,
+            Self::Postpone => Self::Postpone,
+        }
+    }
+
+    fn or(&self, other: &Self) -> Self {
+        match (self, other) {
+            (Self::Keep, _) | (_, Self::Keep) => Self::Keep,
+            (Self::Postpone, _) | (_, Self::Postpone) => Self::Postpone,
+            (Self::Discard, Self::Discard) => Self::Discard,
+        }
+    }
+
+    fn and(&self, other: &Self) -> Self {
+        match (self, other) {
+            (Self::Discard, _) | (_, Self::Discard) => Self::Discard,
+            (Self::Postpone, _) | (_, Self::Postpone) => Self::Postpone,
+            (Self::Keep, Self::Keep) => Self::Keep,
+        }
+    }
+
+    fn is_keep(&self) -> bool {
+        !matches!(self, Self::Discard)
+    }
+}
+
+// ----- Search Key things ---
+fn is_sk_flag(sk: &SearchKey) -> bool {
+    use SearchKey::*;
+    match sk {
+        Answered | Deleted | Draft | Flagged | Keyword(..) | New | Old | Recent | Seen
+        | Unanswered | Undeleted | Undraft | Unflagged | Unkeyword(..) | Unseen => true,
+        _ => false,
+    }
+}
+
+fn is_keep_flag(sk: &SearchKey, midx: &MailIndex) -> bool {
+    use SearchKey::*;
+    match sk {
+        Answered => midx.is_flag_set("\\Answered"),
+        Deleted => midx.is_flag_set("\\Deleted"),
+        Draft => midx.is_flag_set("\\Draft"),
+        Flagged => midx.is_flag_set("\\Flagged"),
+        Keyword(kw) => midx.is_flag_set(kw.inner()),
+        New => {
+            let is_recent = midx.is_flag_set("\\Recent");
+            let is_seen = midx.is_flag_set("\\Seen");
+            is_recent && !is_seen
+        }
+        Old => {
+            let is_recent = midx.is_flag_set("\\Recent");
+            !is_recent
+        }
+        Recent => midx.is_flag_set("\\Recent"),
+        Seen => midx.is_flag_set("\\Seen"),
+        Unanswered => {
+            let is_answered = midx.is_flag_set("\\Recent");
+            !is_answered
+        }
+        Undeleted => {
+            let is_deleted = midx.is_flag_set("\\Deleted");
+            !is_deleted
+        }
+        Undraft => {
+            let is_draft = midx.is_flag_set("\\Draft");
+            !is_draft
+        }
+        Unflagged => {
+            let is_flagged = midx.is_flag_set("\\Flagged");
+            !is_flagged
+        }
+        Unkeyword(kw) => {
+            let is_keyword_set = midx.is_flag_set(kw.inner());
+            !is_keyword_set
+        }
+        Unseen => {
+            let is_seen = midx.is_flag_set("\\Seen");
+            !is_seen
+        }
+
+        // Not flag logic
+        _ => unreachable!(),
+    }
+}
+
+fn is_sk_seq(sk: &SearchKey) -> bool {
+    use SearchKey::*;
+    match sk {
+        SequenceSet(..) | Uid(..) => true,
+        _ => false,
+    }
+}
+fn is_keep_seq(sk: &SearchKey, midx: &MailIndex) -> bool {
+    use SearchKey::*;
+    match sk {
+        SequenceSet(seq_set) => seq_set
+            .0
+            .as_ref()
+            .iter()
+            .any(|seq| midx.is_in_sequence_i(seq)),
+        Uid(seq_set) => seq_set
+            .0
+            .as_ref()
+            .iter()
+            .any(|seq| midx.is_in_sequence_uid(seq)),
+        _ => unreachable!(),
+    }
+}
+
+fn is_keep_modseq(
+    filter: &Option<MetadataItemSearch>,
+    modseq: &NonZeroU64,
+    midx: &MailIndex,
+) -> bool {
+    if filter.is_some() {
+        tracing::warn!(filter=?filter, "Ignoring search metadata filter as it's not supported yet");
+    }
+    modseq <= &midx.modseq
+}