src/imap/command/examined.rs

@@ -111,15 +111,17 @@ impl<'a> ExaminedContext<'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/index.rs

@@ -1,7 +1,7 @@
 use std::num::NonZeroU32;
 
 use anyhow::{anyhow, bail, Result};
-use imap_codec::imap_types::sequence::{self, SequenceSet};
+use imap_codec::imap_types::sequence::{self, Sequence, SequenceSet, SeqOrUid};
 
 use crate::mail::uidindex::{ImapUid, UidIndex};
 use crate::mail::unique_ident::UniqueIdent;
@@ -87,9 +87,47 @@ impl<'a> Index<'a> {
     }
 }
 
+#[derive(Clone)]
 pub struct MailIndex<'a> {
     pub i: NonZeroU32,
     pub uid: ImapUid,
     pub uuid: UniqueIdent,
     pub flags: &'a Vec<String>,
 }
+
+impl<'a> MailIndex<'a> {
+    // The following functions are used to implement the SEARCH command    
+    pub fn is_in_sequence_i(&self, seq: &Sequence) -> bool {
+        match seq {
+            Sequence::Single(SeqOrUid::Asterisk) => true,
+            Sequence::Single(SeqOrUid::Value(target)) => target == &self.i,
+            Sequence::Range(SeqOrUid::Asterisk, SeqOrUid::Value(x)) 
+                | Sequence::Range(SeqOrUid::Value(x), SeqOrUid::Asterisk) => x <= &self.i,
+            Sequence::Range(SeqOrUid::Value(x1), SeqOrUid::Value(x2)) => if x1 < x2 {
+                x1 <= &self.i && &self.i <= x2
+            } else {
+                x1 >= &self.i && &self.i >= x2
+            },
+            Sequence::Range(SeqOrUid::Asterisk, SeqOrUid::Asterisk) => true,
+        }
+    }
+
+    pub fn is_in_sequence_uid(&self, seq: &Sequence) -> bool {
+        match seq {
+            Sequence::Single(SeqOrUid::Asterisk) => true,
+            Sequence::Single(SeqOrUid::Value(target)) => target == &self.uid,
+            Sequence::Range(SeqOrUid::Asterisk, SeqOrUid::Value(x))
+                | Sequence::Range(SeqOrUid::Value(x),SeqOrUid::Asterisk) => x <= &self.uid,
+            Sequence::Range(SeqOrUid::Value(x1), SeqOrUid::Value(x2)) => if x1 < x2 {
+                x1 <= &self.uid && &self.uid <= x2
+            } else {
+                x1 >= &self.uid && &self.uid >= x2
+            },
+            Sequence::Range(SeqOrUid::Asterisk, SeqOrUid::Asterisk) => true,
+        }
+    }
+
+    pub fn is_flag_set(&self, flag: &str) -> bool {
+        self.flags.iter().any(|candidate| candidate.as_str() == flag)
+    }
+}

src/imap/mail_view.rs

@@ -52,6 +52,44 @@ impl<'a> MailView<'a> {
         })
     }
 
+    pub fn filter(&self, ap: &AttributesProxy) -> Result<(Body<'static>, SeenFlag)> {
+        let mut seen = SeenFlag::DoNothing;
+        let res_attrs = ap
+            .attrs
+            .iter()
+            .map(|attr| match attr {
+                MessageDataItemName::Uid => Ok(self.uid()),
+                MessageDataItemName::Flags => Ok(self.flags()),
+                MessageDataItemName::Rfc822Size => self.rfc_822_size(),
+                MessageDataItemName::Rfc822Header => self.rfc_822_header(),
+                MessageDataItemName::Rfc822Text => self.rfc_822_text(),
+                MessageDataItemName::Rfc822 => self.rfc822(),
+                MessageDataItemName::Envelope => Ok(self.envelope()),
+                MessageDataItemName::Body => self.body(),
+                MessageDataItemName::BodyStructure => self.body_structure(),
+                MessageDataItemName::BodyExt {
+                    section,
+                    partial,
+                    peek,
+                } => {
+                    let (body, has_seen) = self.body_ext(section, partial, peek)?;
+                    seen = has_seen;
+                    Ok(body)
+                }
+                MessageDataItemName::InternalDate => self.internal_date(),
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+
+        Ok((
+            Body::Data(Data::Fetch {
+                seq: self.in_idx.i,
+                items: res_attrs.try_into()?,
+            }),
+            seen,
+        ))
+    }
+
+    // Private function, mainly for filter!
     fn uid(&self) -> MessageDataItem<'static> {
         MessageDataItem::Uid(self.in_idx.uid.clone())
     }
@@ -168,42 +206,6 @@ impl<'a> MailView<'a> {
         Ok(MessageDataItem::InternalDate(DateTime::unvalidated(dt)))
     }
 
-    pub fn filter(&self, ap: &AttributesProxy) -> Result<(Body<'static>, SeenFlag)> {
-        let mut seen = SeenFlag::DoNothing;
-        let res_attrs = ap
-            .attrs
-            .iter()
-            .map(|attr| match attr {
-                MessageDataItemName::Uid => Ok(self.uid()),
-                MessageDataItemName::Flags => Ok(self.flags()),
-                MessageDataItemName::Rfc822Size => self.rfc_822_size(),
-                MessageDataItemName::Rfc822Header => self.rfc_822_header(),
-                MessageDataItemName::Rfc822Text => self.rfc_822_text(),
-                MessageDataItemName::Rfc822 => self.rfc822(),
-                MessageDataItemName::Envelope => Ok(self.envelope()),
-                MessageDataItemName::Body => self.body(),
-                MessageDataItemName::BodyStructure => self.body_structure(),
-                MessageDataItemName::BodyExt {
-                    section,
-                    partial,
-                    peek,
-                } => {
-                    let (body, has_seen) = self.body_ext(section, partial, peek)?;
-                    seen = has_seen;
-                    Ok(body)
-                }
-                MessageDataItemName::InternalDate => self.internal_date(),
-            })
-            .collect::<Result<Vec<_>, _>>()?;
-
-        Ok((
-            Body::Data(Data::Fetch {
-                seq: self.in_idx.i,
-                items: res_attrs.try_into()?,
-            }),
-            seen,
-        ))
-    }
 }
 
 pub enum SeenFlag {

src/imap/mailbox_view.rs

@@ -319,12 +319,18 @@ impl MailboxView {
         let selection = self.index().fetch(&seq_set, seq_type.is_uid())?;
 
         // 3. Filter the selection based on the ID / UID / Flags
+        let selection = crit.filter_on_idx(&selection);
 
-        // 4. If needed, filter the selection based on the metadata
-        let _need_meta = crit.need_meta();
+        // 4. Fetch additional info about the emails
+        let query_scope = crit.query_scope();
+        let uuids = selection
+            .iter()
+            .map(|midx| midx.uuid)
+            .collect::<Vec<_>>();
+        let query_result = self.0.query(&uuids, query_scope).fetch().await?;
 
         // 5. If needed, filter the selection based on the body
-        let _need_body = crit.need_body();
+        let selection = crit.filter_on_query(&selection, &query_result);
 
         // 6. Format the result according to the client's taste:
         // either return UID or ID.

src/imap/search.rs

@@ -3,6 +3,9 @@ use imap_codec::imap_types::search::SearchKey;
 use imap_codec::imap_types::sequence::{SeqOrUid, Sequence, SequenceSet};
 use std::num::NonZeroU32;
 
+use crate::mail::query::{QueryScope, QueryResult};
+use crate::imap::index::MailIndex;
+
 pub enum SeqType {
     Undefined,
     NonUid,
@@ -54,6 +57,10 @@ impl<'a> Criteria<'a> {
                 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()
@@ -72,31 +79,119 @@ impl<'a> Criteria<'a> {
     /// 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 need_meta(&self) -> bool {
+    pub fn query_scope(&self) -> QueryScope {
         use SearchKey::*;
         match self.0 {
             // IMF Headers
             Bcc(_) | Cc(_) | From(_) | Header(..) | SentBefore(_) | SentOn(_) | SentSince(_)
-            | Subject(_) | To(_) => true,
+            | Subject(_) | To(_) => QueryScope::Partial,
             // Internal Date is also stored in MailMeta
-            Before(_) | On(_) | Since(_) => true,
+            Before(_) | On(_) | Since(_) => QueryScope::Partial,
             // Message size is also stored in MailMeta
-            Larger(_) | Smaller(_) => true,
-            And(and_list) => and_list.as_ref().iter().any(|sk| Criteria(sk).need_meta()),
-            Not(inner) => Criteria(inner).need_meta(),
-            Or(left, right) => Criteria(left).need_meta() || Criteria(right).need_meta(),
-            _ => false,
+            Larger(_) | Smaller(_) => QueryScope::Partial,
+            // Text and Body require that we fetch the full content!
+            Text(_) | Body(_) => QueryScope::Full,
+            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()),
+            _ => QueryScope::Index,
         }
     }
 
-    pub fn need_body(&self) -> bool {
+    pub fn filter_on_idx<'b>(&self, midx_list: &[MailIndex<'b>]) -> Vec<MailIndex<'b>> {
+        midx_list
+            .iter()
+            .filter(|x| self.is_keep_on_idx(x).is_keep())
+            .map(|x| (*x).clone())
+            .collect::<Vec<_>>()
+    }
+
+    pub fn filter_on_query(&self, midx_list: &[MailIndex], query_result: &Vec<QueryResult<'_>>) -> Vec<MailIndex> {
+        unimplemented!();
+    }
+
+    // ----
+    
+    /// 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 {
-            Text(_) | Body(_) => true,
-            And(and_list) => and_list.as_ref().iter().any(|sk| Criteria(sk).need_body()),
-            Not(inner) => Criteria(inner).need_body(),
-            Or(left, right) => Criteria(left).need_body() || Criteria(right).need_body(),
-            _ => false,
+            // 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
+            SequenceSet(seq_set) => seq_set.0.as_ref().iter().fold(PartialDecision::Discard, |acc, seq| {
+                let local_decision: PartialDecision = midx.is_in_sequence_i(seq).into();
+                acc.or(&local_decision)
+            }),
+            Uid(seq_set) => seq_set.0.as_ref().iter().fold(PartialDecision::Discard, |acc, seq| {
+                let local_decision: PartialDecision = midx.is_in_sequence_uid(seq).into();
+                acc.or(&local_decision)
+            }),
+
+            // Flag logic
+            Answered => midx.is_flag_set("\\Answered").into(),
+            Deleted => midx.is_flag_set("\\Deleted").into(),
+            Draft => midx.is_flag_set("\\Draft").into(),
+            Flagged => midx.is_flag_set("\\Flagged").into(),
+            Keyword(kw) => midx.is_flag_set(kw.inner()).into(),
+            New => {
+                let is_recent: PartialDecision = midx.is_flag_set("\\Recent").into();
+                let is_seen: PartialDecision = midx.is_flag_set("\\Seen").into();
+                is_recent.and(&is_seen.not())
+            },
+            Old => {
+                let is_recent: PartialDecision = midx.is_flag_set("\\Recent").into();
+                is_recent.not()
+            },
+            Recent =>  midx.is_flag_set("\\Recent").into(),
+            Seen =>  midx.is_flag_set("\\Seen").into(),
+            Unanswered =>  {
+                let is_answered: PartialDecision = midx.is_flag_set("\\Recent").into();
+                is_answered.not()
+            },
+            Undeleted => {
+                let is_deleted: PartialDecision = midx.is_flag_set("\\Deleted").into();
+                is_deleted.not()
+            },
+            Undraft => {
+                let is_draft: PartialDecision = midx.is_flag_set("\\Draft").into();
+                is_draft.not()
+            },
+            Unflagged => {
+                let is_flagged: PartialDecision = midx.is_flag_set("\\Flagged").into();
+                is_flagged.not()
+            },
+            Unkeyword(kw) => {
+                let is_keyword_set: PartialDecision = midx.is_flag_set(kw.inner()).into();
+                is_keyword_set.not()
+            },
+            Unseen => {
+                let is_seen: PartialDecision = midx.is_flag_set("\\Seen").into();
+                is_seen.not()
+            },
+            
+            // 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,
         }
     }
 }
@@ -128,3 +223,46 @@ fn approx_sequence_size(seq: &Sequence) -> u64 {
         }
     }
 }
+
+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::Postpone, _) | (_, Self::Postpone) => Self::Postpone,
+            (Self::Keep, _) | (_, Self::Keep) => Self::Keep,
+            (Self::Discard, Self::Discard) => Self::Discard,
+        }
+    }
+
+    fn and(&self, other: &Self) -> Self {
+        match (self, other) {
+            (Self::Postpone, _) | (_, Self::Postpone) => Self::Postpone,
+            (Self::Discard, _) | (_, Self::Discard) => Self::Discard,
+            (Self::Keep, Self::Keep) => Self::Keep,
+        }
+    }
+
+    fn is_keep(&self) -> bool {
+        !matches!(self, Self::Discard)
+    }
+}

src/mail/mod.rs

@@ -1,5 +1,4 @@
 use std::convert::TryFrom;
-use std::io::Write;
 
 pub mod incoming;
 pub mod mailbox;

src/mail/query.rs

@@ -19,6 +19,15 @@ pub enum QueryScope {
     Partial,
     Full,
 }
+impl QueryScope {
+    pub fn union(&self, other: &QueryScope) -> QueryScope {
+        match (self, other) {
+            (QueryScope::Full, _) | (_, QueryScope::Full) => QueryScope::Full,
+            (QueryScope::Partial, _) | (_, QueryScope::Partial) => QueryScope::Partial,
+            (QueryScope::Index, QueryScope::Index) => QueryScope::Index,
+        }
+    }
+}
 
 impl<'a, 'b> Query<'a, 'b> {
     pub async fn fetch(&self) -> Result<Vec<QueryResult<'a>>> {