src/imap/command/selected.rs

@@ -136,15 +136,17 @@ impl<'a> SelectedContext<'a> {
 
     pub async fn search(
         self,
-        _charset: &Option<Charset<'a>>,
-        _criteria: &SearchKey<'a>,
-        _uid: &bool,
+        charset: &Option<Charset<'a>>,
+        criteria: &SearchKey<'a>,
+        uid: &bool,
     ) -> Result<(Response<'static>, flow::Transition)> {
+        let found = self.mailbox.search(charset, criteria, *uid).await?;
         Ok((
             Response::build()
                 .to_req(self.req)
-                .message("Not implemented")
-                .bad()?,
+                .set_body(found)
+                .message("SEARCH completed")
+                .ok()?,
             flow::Transition::None,
         ))
     }

src/imap/mailbox_view.rs

@@ -5,15 +5,18 @@ use anyhow::{anyhow, bail, Error, Result};
 
 use futures::stream::{FuturesOrdered, StreamExt};
 
+use imap_codec::imap_types::core::Charset;
 use imap_codec::imap_types::fetch::{MacroOrMessageDataItemNames, MessageDataItem};
 use imap_codec::imap_types::flag::{Flag, FlagFetch, FlagPerm, StoreResponse, StoreType};
 use imap_codec::imap_types::response::{Code, Data, Status};
+use imap_codec::imap_types::search::SearchKey;
 use imap_codec::imap_types::sequence::{self, SequenceSet};
 
 use crate::imap::attributes::AttributesProxy;
 use crate::imap::flags;
 use crate::imap::mail_view::SeenFlag;
 use crate::imap::response::Body;
+use crate::imap::search;
 use crate::imap::selectors::MailSelectionBuilder;
 use crate::mail::mailbox::Mailbox;
 use crate::mail::uidindex::{ImapUid, ImapUidvalidity, UidIndex};
@@ -308,6 +311,7 @@ impl MailboxView {
             .iter()
             .filter_map(|mv| mv.filter(&ap).ok().map(|(body, seen)| (mv, body, seen)))
             .collect::<Vec<_>>();
+
         // Register seen flags
         let future_flags = filtered_view
             .iter()
@@ -333,6 +337,22 @@ impl MailboxView {
         Ok(command_body)
     }
 
+    /// A very naive search implementation...
+    pub async fn search<'a>(
+        &self,
+        _charset: &Option<Charset<'a>>,
+        search_key: &SearchKey<'a>,
+        uid: bool,
+    ) -> Result<Vec<Body<'static>>> {
+        let (seq_set, seq_type) = search::Criteria(search_key).to_sequence_set();
+        let mailids = MailIdentifiersList(self.get_mail_ids(&seq_set, seq_type.is_uid())?);
+        let mail_u32 = match uid {
+            true => mailids.uids(),
+            _ => mailids.ids(),
+        };
+        Ok(vec![Body::Data(Data::Search(mail_u32))])
+    }
+
     // ----
 
     // Gets the IMAP ID, the IMAP UIDs and, the Aerogramme UUIDs of mails identified by a SequenceSet of
@@ -525,6 +545,12 @@ pub struct MailIdentifiers {
 pub struct MailIdentifiersList(Vec<MailIdentifiers>);
 
 impl MailIdentifiersList {
+    fn ids(&self) -> Vec<NonZeroU32> {
+        self.0.iter().map(|mi| mi.i).collect()
+    }
+    fn uids(&self) -> Vec<ImapUid> {
+        self.0.iter().map(|mi| mi.uid).collect()
+    }
     fn uuids(&self) -> Vec<UniqueIdent> {
         self.0.iter().map(|mi| mi.uuid).collect()
     }

src/imap/mod.rs

@@ -8,6 +8,7 @@ mod mail_view;
 mod mailbox_view;
 mod mime_view;
 mod response;
+mod search;
 mod selectors;
 mod session;
 

src/imap/search.rs

@@ -0,0 +1,107 @@
+use imap_codec::imap_types::core::NonEmptyVec;
+use imap_codec::imap_types::search::SearchKey;
+use imap_codec::imap_types::sequence::{SeqOrUid, Sequence, SequenceSet};
+use std::num::NonZeroU32;
+
+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(
+                            NonEmptyVec::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"
+                );
+                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),
+        }
+    }
+
+    fn need_meta(&self) {
+        unimplemented!();
+    }
+
+    fn need_body(&self) {
+        unimplemented!();
+    }
+}
+
+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
+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)
+        }
+    }
+}