From fc2d9a684dac1a4b0bbb93a51a499c5607402fa1 Mon Sep 17 00:00:00 2001
From: Manos Pitsidianakis <el13635@mail.ntua.gr>
Date: Mon, 18 Nov 2019 13:00:43 +0200
Subject: [PATCH] melib/imap: set has_attachments based on BODYSTRUCTURE

fetch BODYSTRUCTURE along with ENVELOPE from server and set
has_attachments based on the MIME structure of the envelope.

Notes: BODYSTRUCTURE returns the MIME structure of the envelope without
the data, so if it includes a multipart/mixed it *should* have
attachments.
ENVELOPE returns basic headers of the message like Sender, Subject, Date
etc.
---
 melib/src/backends/imap.rs                 |  2 +-
 melib/src/backends/imap/protocol_parser.rs | 15 ++++++++++++++-
 melib/src/email.rs                         |  5 +++++
 melib/src/email/parser.rs                  |  7 +++++++
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/melib/src/backends/imap.rs b/melib/src/backends/imap.rs
index 8cc7aed3..42305545 100644
--- a/melib/src/backends/imap.rs
+++ b/melib/src/backends/imap.rs
@@ -179,7 +179,7 @@ impl MailBackend for ImapType {
                 while exists > 1 {
                     let mut envelopes = vec![];
                     exit_on_error!(&tx,
-                                   conn.send_command(format!("UID FETCH {}:{} (UID FLAGS ENVELOPE)", std::cmp::max(exists.saturating_sub(20000), 1), exists).as_bytes())
+                                   conn.send_command(format!("UID FETCH {}:{} (UID FLAGS ENVELOPE BODYSTRUCTURE)", std::cmp::max(exists.saturating_sub(20000), 1), exists).as_bytes())
                                    conn.read_response(&mut response)
                     );
                     debug!(
diff --git a/melib/src/backends/imap/protocol_parser.rs b/melib/src/backends/imap/protocol_parser.rs
index 6d806aa9..ca286acd 100644
--- a/melib/src/backends/imap/protocol_parser.rs
+++ b/melib/src/backends/imap/protocol_parser.rs
@@ -1,4 +1,5 @@
 use super::*;
+use crate::email::parser::BytesExt;
 use nom::{digit, is_digit, rest, IResult};
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};
@@ -597,8 +598,20 @@ named!(
             >> uid_flags: permutation!(preceded!(ws!(tag!("UID ")), map_res!(digit, |s| { usize::from_str(unsafe { std::str::from_utf8_unchecked(s) }) })), opt!(preceded!(ws!(tag!("FLAGS ")), delimited!(tag!("("), byte_flags, tag!(")")))))
             >> tag!(" ENVELOPE ")
             >> env: ws!(envelope)
+            >> tag!("BODYSTRUCTURE ")
+            >> bodystructure: take_until!(")\r\n")
             >> tag!(")\r\n")
-            >> ((uid_flags.0, uid_flags.1, env))
+            >> ({
+                let mut env = env;
+                debug!(unsafe { std::str::from_utf8_unchecked(bodystructure) });
+                let has_attachments = bodystructure_has_attachments(bodystructure);
+                env.set_has_attachments(has_attachments);
+                (uid_flags.0, uid_flags.1, env)
+            })
         )
     )
 );
+
+pub fn bodystructure_has_attachments(input: &[u8]) -> bool {
+    input.rfind(b" \"mixed\" ").is_some() || input.rfind(b" \"MIXED\" ").is_some()
+}
diff --git a/melib/src/email.rs b/melib/src/email.rs
index 20f83aeb..494ba4e7 100644
--- a/melib/src/email.rs
+++ b/melib/src/email.rs
@@ -588,6 +588,11 @@ impl Envelope {
     pub fn is_seen(&self) -> bool {
         self.flags.contains(Flag::SEEN)
     }
+
+    pub fn set_has_attachments(&mut self, new_val: bool) {
+        self.has_attachments = new_val;
+    }
+
     pub fn has_attachments(&self) -> bool {
         self.has_attachments
     }
diff --git a/melib/src/email/parser.rs b/melib/src/email/parser.rs
index 747ac747..ef03353e 100644
--- a/melib/src/email/parser.rs
+++ b/melib/src/email/parser.rs
@@ -53,6 +53,7 @@ pub trait BytesExt {
     fn ltrim(&self) -> &Self;
     fn trim(&self) -> &Self;
     fn find(&self, needle: &[u8]) -> Option<usize>;
+    fn rfind(&self, needle: &[u8]) -> Option<usize>;
     fn replace(&self, from: &[u8], to: &[u8]) -> Vec<u8>;
 }
 
@@ -79,6 +80,12 @@ impl BytesExt for [u8] {
         self.windows(needle.len())
             .position(|window| window == needle)
     }
+
+    fn rfind(&self, needle: &[u8]) -> Option<usize> {
+        self.windows(needle.len())
+            .rposition(|window| window == needle)
+    }
+
     fn replace(&self, from: &[u8], to: &[u8]) -> Vec<u8> {
         let mut ret = self.to_vec();
         if let Some(idx) = self.find(from) {