From d3c156a087f3c767fc0d2376abd7c1d304161d47 Mon Sep 17 00:00:00 2001
From: Quentin Dufour <quentin@deuxfleurs.fr>
Date: Fri, 5 Jan 2024 15:26:57 +0100
Subject: [PATCH] Select what to fecth for search

---
 Cargo.lock               |  2 +-
 Cargo.toml               |  2 +-
 src/imap/mailbox_view.rs |  9 ++++++++-
 src/imap/search.rs       | 30 ++++++++++++++++++++++++++----
 4 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a6a01b9..2c264f2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1723,7 +1723,7 @@ dependencies = [
  "httpdate",
  "itoa",
  "pin-project-lite 0.2.13",
- "socket2 0.5.5",
+ "socket2 0.4.10",
  "tokio",
  "tower-service",
  "tracing",
diff --git a/Cargo.toml b/Cargo.toml
index b110a6a..68a46e3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -58,7 +58,7 @@ aws-sdk-s3 = "1.9.0"
 eml-codec = { git = "https://git.deuxfleurs.fr/Deuxfleurs/eml-codec.git", branch = "main" }
 smtp-message = { git = "http://github.com/Alexis211/kannader", branch = "feature/lmtp" }
 smtp-server = { git = "http://github.com/Alexis211/kannader", branch = "feature/lmtp" }
-imap-codec = { version = "1.0.0", features = ["quirk_crlf_relaxed", "bounded-static", "ext_condstore_qresync"] }
+imap-codec = { version = "1.0.0", features = ["bounded-static", "ext_condstore_qresync"] }
 imap-flow = { git = "https://github.com/duesee/imap-flow.git", rev = "e45ce7bb6ab6bda3c71a0c7b05e9b558a5902e90" }
 
 [dev-dependencies]
diff --git a/src/imap/mailbox_view.rs b/src/imap/mailbox_view.rs
index 5311635..4d0858f 100644
--- a/src/imap/mailbox_view.rs
+++ b/src/imap/mailbox_view.rs
@@ -344,12 +344,19 @@ impl MailboxView {
         search_key: &SearchKey<'a>,
         uid: bool,
     ) -> Result<Vec<Body<'static>>> {
-        let (seq_set, seq_type) = search::Criteria(search_key).to_sequence_set();
+        // 1. Compute the subset of sequence identifiers we need to fetch
+        let query = search::Criteria(search_key);
+        let (seq_set, seq_type) = query.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(),
         };
+
+        // 2. Compute wether we will need to fetch the mail meta and/or the body
+        let _need_meta = query.need_meta();
+        let _need_body = query.need_body();
+
         Ok(vec![Body::Data(Data::Search(mail_u32))])
     }
 
diff --git a/src/imap/search.rs b/src/imap/search.rs
index bf1d30e..ef89288 100644
--- a/src/imap/search.rs
+++ b/src/imap/search.rs
@@ -69,12 +69,34 @@ impl<'a> Criteria<'a> {
         }
     }
 
-    fn need_meta(&self) {
-        unimplemented!();
+    /// 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 {
+        use SearchKey::*;
+        match self.0 {
+            // IMF Headers
+            Bcc(_) | Cc(_) | From(_) | Header(..) | SentBefore(_) | SentOn(_) | SentSince(_) | Subject(_) | To(_) => true,
+            // Internal Date is also stored in MailMeta
+            Before(_) | On(_) | Since(_) => true,
+            // 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,
+        }
     }
 
-    fn need_body(&self) {
-        unimplemented!();
+    pub fn need_body(&self) -> bool {
+        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,
+        }
     }
 }