1 files changed, 77 insertions, 0 deletions
diff --git a/aero-proto/src/imap/attributes.rs b/aero-proto/src/imap/attributes.rs
new file mode 100644
index 0000000..89446a8
--- /dev/null
+++ b/aero-proto/src/imap/attributes.rs
@@ -0,0 +1,77 @@
+use imap_codec::imap_types::command::FetchModifier;
+use imap_codec::imap_types::fetch::{MacroOrMessageDataItemNames, MessageDataItemName, Section};
+
+/// Internal decisions based on fetched attributes
+/// passed by the client
+
+pub struct AttributesProxy {
+    pub attrs: Vec<MessageDataItemName<'static>>,
+}
+impl AttributesProxy {
+    pub fn new(
+        attrs: &MacroOrMessageDataItemNames<'static>,
+        modifiers: &[FetchModifier],
+        is_uid_fetch: bool,
+    ) -> Self {
+        // Expand macros
+        let mut fetch_attrs = match attrs {
+            MacroOrMessageDataItemNames::Macro(m) => {
+                use imap_codec::imap_types::fetch::Macro;
+                use MessageDataItemName::*;
+                match m {
+                    Macro::All => vec![Flags, InternalDate, Rfc822Size, Envelope],
+                    Macro::Fast => vec![Flags, InternalDate, Rfc822Size],
+                    Macro::Full => vec![Flags, InternalDate, Rfc822Size, Envelope, Body],
+                    _ => {
+                        tracing::error!("unimplemented macro");
+                        vec![]
+                    }
+                }
+            }
+            MacroOrMessageDataItemNames::MessageDataItemNames(a) => a.clone(),
+        };
+
+        // Handle uids
+        if is_uid_fetch && !fetch_attrs.contains(&MessageDataItemName::Uid) {
+            fetch_attrs.push(MessageDataItemName::Uid);
+        }
+
+        // Handle inferred MODSEQ tag
+        let is_changed_since = modifiers
+            .iter()
+            .any(|m| matches!(m, FetchModifier::ChangedSince(..)));
+        if is_changed_since && !fetch_attrs.contains(&MessageDataItemName::ModSeq) {
+            fetch_attrs.push(MessageDataItemName::ModSeq);
+        }
+
+        Self { attrs: fetch_attrs }
+    }
+
+    pub fn is_enabling_condstore(&self) -> bool {
+        self.attrs
+            .iter()
+            .any(|x| matches!(x, MessageDataItemName::ModSeq))
+    }
+
+    pub fn need_body(&self) -> bool {
+        self.attrs.iter().any(|x| match x {
+            MessageDataItemName::Body
+            | MessageDataItemName::Rfc822
+            | MessageDataItemName::Rfc822Text
+            | MessageDataItemName::BodyStructure => true,
+
+            MessageDataItemName::BodyExt {
+                section: Some(section),
+                partial: _,
+                peek: _,
+            } => match section {
+                Section::Header(None)
+                | Section::HeaderFields(None, _)
+                | Section::HeaderFieldsNot(None, _) => false,
+                _ => true,
+            },
+            MessageDataItemName::BodyExt { .. } => true,
+            _ => false,
+        })
+    }
+}