From 35ff86945423f2706bd9ea610bd85c1d0ffe20c1 Mon Sep 17 00:00:00 2001
From: Quentin Dufour <quentin@deuxfleurs.fr>
Date: Tue, 13 Jun 2023 16:22:04 +0200
Subject: [PATCH] Informational fields support

---
 src/headers.rs | 60 +++++++++++++++++++++++++++++++++++++++++++++-----
 src/model.rs   | 12 +++++++++-
 src/parse.rs   |  4 ++++
 3 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/src/headers.rs b/src/headers.rs
index 26f9bcc..9967f56 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -6,14 +6,13 @@ use nom::{
     bytes::complete::tag,
     character::complete::space0,
     combinator::opt,
-    multi::fold_many0,
-    multi::{many0, many1},
+    multi::{many0, many1, fold_many0, separated_list1},
     sequence::tuple,
 };
 
 use crate::whitespace::{fws, perm_crlf};
 use crate::words::vchar_seq;
-use crate::misc_token::unstructured;
+use crate::misc_token::{phrase, unstructured};
 use crate::model::{PermissiveHeaderSection, HeaderDate, MailboxRef, AddressRef};
 use crate::mailbox::mailbox;
 use crate::address::{mailbox_list, address_list, address_list_cfws};
@@ -82,10 +81,25 @@ pub fn header_section(input: &str) -> IResult<&str, PermissiveHeaderSection> {
                     section.references = id_list;
                 }
 
-
+                // 3.6.5.  Informational Fields
                 HeaderField::Subject(title) => {
+                    //    | subject        | 0      | 1          |                            |
                     section.subject = Some(title);
+                }               
+                HeaderField::Comments(coms) => {
+                    //    | comments       | 0      | unlimited  |                            |
+                    section.comments.push(coms);
                 }
+                HeaderField::Keywords(mut kws) => {
+                    //    | keywords       | 0      | unlimited  |                            |
+                    section.keywords.append(&mut kws);
+                }
+
+                // 3.6.6.  Resent Fields
+
+                // 3.6.7.  Trace Fields
+
+                // 3.6.8.  Optional Fields
                 HeaderField::Optional(name, body) => {
                     section.optional.insert(name, body);
                 }
@@ -122,7 +136,7 @@ enum HeaderField<'a> {
     // 3.6.5.  Informational Fields
     Subject(String),
     Comments(String),
-    Keywords(Vec<&'a str>),
+    Keywords(Vec<String>),
 
     // 3.6.6.  Resent Fields
     ResentDate,
@@ -204,11 +218,25 @@ fn header_field(input: &str) -> IResult<&str, HeaderField> {
             (input, HeaderField::References(body))
         },
 
-        // Rest
+        // 3.6.5.  Informational Fields
         "Subject" => {
             let (input, body) = unstructured(input)?;
             (input, HeaderField::Subject(body))
         },
+        "Comments" => {
+            let (input, body) = unstructured(input)?;
+            (input, HeaderField::Comments(body))
+        }
+        "Keywords" => {
+            let (input, body) = separated_list1(tag(","), phrase)(input)?;
+            (input, HeaderField::Keywords(body))
+        }
+
+        // 3.6.6.  Resent Fields
+
+        // 3.6.7.  Trace Fields
+
+        // 3.6.8.  Optional Fields
         _ => {
             let (input, body) = unstructured(input)?;
             (input, HeaderField::Optional(field_name, body))
@@ -364,6 +392,26 @@ mod tests {
             ])))
         );
     }
+
+    // 3.6.5.  Informational Fields
+    fn test_subject() {
+        assert_eq!(
+            header_field("Subject: Aérogramme\r\n"),
+            Ok(("", HeaderField::Subject("Aérogramme".into())))
+        );
+    }
+    fn test_comments() {
+        assert_eq!(
+            header_field("Comments: 😛 easter egg!\r\n"),
+            Ok(("", HeaderField::Comments("😛 easter egg!".into())))
+        );
+    }
+    fn test_keywords() {
+        assert_eq!(
+            header_field("Keywords: fantasque, farfelu, fanfreluche\r\n"),
+            Ok(("", HeaderField::Keywords(vec!["fantasque".into(), "farfelu".into(), "fanfreluche".into()])))
+        );
+    }
 }
 
 
diff --git a/src/model.rs b/src/model.rs
index aa466b0..9c4afa9 100644
--- a/src/model.rs
+++ b/src/model.rs
@@ -88,9 +88,19 @@ pub struct PermissiveHeaderSection<'a> {
     pub msg_id: Option<MessageId<'a>>,
     pub in_reply_to: Vec<MessageId<'a>>,
     pub references: Vec<MessageId<'a>>,
+    
+    // 3.6.5.  Informational Fields
+    pub subject: Option<String>,
+    pub comments: Vec<String>,
+    pub keywords: Vec<String>,
+
+    // 3.6.6.  Resent Fields
+
+    // 3.6.7.  Trace Fields
+
+    // 3.6.8.  Optional Fields
 
     // Rest
-    pub subject: Option<String>,
     pub optional: HashMap<&'a str, String>,
 }
 
diff --git a/src/parse.rs b/src/parse.rs
index d602065..d70968c 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -10,6 +10,10 @@ To: John Doe <jdoe@machine.example>
 Cc: imf2@example.com
 Bcc: (hidden)
 Subject: Re: Saying Hello
+Comments: A simple message
+Comments: Not that complicated
+Keywords: hello, world
+Keywords: salut, le, monde
 Message-ID: <3456@example.net>
 In-Reply-To: <1234@local.machine.example>
 References: <1234@local.machine.example>