Code polish

- Fix some typos.
- Added more comments (and documentation) to the code.

src/types/errors.rs

@@ -11,7 +11,7 @@ pub enum HuskError {
     #[error("Cannot find the local trust root")]
     NoLocalTrustRoot,
     #[error("The local trust root is damaged - {0}")]
-    DamangedLocalTrustRoot(String),
+    DamagedLocalTrustRoot(String),
     #[error("Cannot access cert store")]
     NoCertStore,
     #[error("No encryption keys found")]

src/types/husk_context.rs

@@ -1,6 +1,12 @@
 //! HuskContext
 //!
-//! Keep data in HuskContext while processing a mail.
+//! Keep data in `HuskContext` while processing emails. The HuskContext
+//! lives for a complete session with the MTA. A session might contain
+//! more than one email (the session is reused).
+//!
+//! The context of a single mail is stored in a `MailContext`. The
+//! `HuskContext` has a reference to the `MailContext` of the current
+//! email.
 
 use anyhow;
 use sequoia_openpgp::policy::StandardPolicy;
@@ -26,7 +32,7 @@ pub struct HuskContext<'hc> {
 
 impl<'hc> HuskContext<'hc> {
 
-    /// Create a new HuskContext instance
+    /// Create a new HuskContext instance.
     pub fn new(config: &HuskConfig) -> anyhow::Result<HuskContext<'hc>> {
 
         let sequoia_home = Home::new(PathBuf::from(&config.sequoia_home))?;
@@ -48,14 +54,19 @@ impl<'hc> HuskContext<'hc> {
         })
     }
 
-    pub fn set_sender(&mut self, sender: String) {
-        self.mail.set_sender(sender);
-    }
-
+    /// If the `HuskContext` is reused for another email, `reset_mail`
+    /// creates the neccessary context for it.
     pub fn reset_mail(&mut self) {
         self.mail = MailContext::new();
     }
 
+    /// Store the sender of an email in the current `MailContext`.
+    pub fn set_sender(&mut self, sender: String) {
+        self.mail.set_sender(sender);
+    }
+
+    /// Add a recipient to the current `MailContext`, try to fetch the
+    /// corresponding certificate(s).
     pub async fn add_recipient(&mut self, rcpt: String) {
 
         let certs = crypto::get_certificates(self, rcpt.as_str()).await;

src/types/introducer.rs

@@ -108,6 +108,7 @@ use std::fmt::{Display, Formatter};
 impl Display for Introducer {
 
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        // XXX: This is unsafe as ANSI control chars are not handled.
         let uids = self.cert.userids()
             .map(|u| String::from_utf8_lossy(u.userid().value()).to_string())
             .collect::<Vec<String>>()

src/types/mail_context.rs

@@ -1,4 +1,7 @@
 //! Mail Context
+//!
+//! As a mail gets processed by the milter, the `MailContext` is used
+//! to keep the bits and pieces together.
 
 use std::sync::Arc;
 use bytes::{Bytes, BytesMut};