melib: add a `body` field to Attachment

Attachment needs to know the range of bytes where the body part of the
attachment is located. The Attachment.raw field contains the entire
attachment, headers and body. The new Attachment.body fields contains a
`StrBuilder` which contains the offset and length of the body part inside
`raw`.

1 files changed, 4 insertions, 3 deletions

diff --git a/melib/src/email/address.rs b/melib/src/email/address.rs
index dd771d92..4845d328 100644
--- a/melib/src/email/address.rs
+++ b/melib/src/email/address.rs
@@ -129,7 +129,7 @@ impl fmt::Debug for Address {
 }
 
 /// Helper struct to return slices from a struct field on demand.
-#[derive(Clone, Debug, Serialize, Deserialize, Default)]
+#[derive(Clone, Debug, Serialize, Deserialize, Default, PartialEq, Copy)]
 pub struct StrBuilder {
     pub offset: usize,
     pub length: usize,
@@ -146,12 +146,13 @@ pub trait StrBuild {
 }
 
 impl StrBuilder {
-    fn display<'a>(&self, s: &'a [u8]) -> String {
+    pub fn display<'a>(&self, s: &'a [u8]) -> String {
         let offset = self.offset;
         let length = self.length;
         String::from_utf8(s[offset..offset + length].to_vec()).unwrap()
     }
-    fn display_bytes<'a>(&self, b: &'a [u8]) -> &'a [u8] {
+
+    pub fn display_bytes<'a>(&self, b: &'a [u8]) -> &'a [u8] {
         &b[self.offset..(self.offset + self.length)]
     }
 }