target comments from @flub and @dignifiedquire

src/chat.rs

@@ -1608,8 +1608,7 @@ pub fn shall_attach_selfavatar(context: &Context, chat_id: u32) -> Result<bool,
         return Ok(false);
     }
 
-    let resend_every_days = 14;
-    let timestamp_some_days_ago = time() - resend_every_days * 24 * 60 * 60;
+    let timestamp_some_days_ago = time() - DC_RESEND_USER_AVATAR_DAYS * 24 * 60 * 60;
     let needs_attach = context.sql.query_map(
         "SELECT c.selfavatar_sent
            FROM chats_contacts cc

src/constants.rs

@@ -58,6 +58,9 @@ pub const DC_GCM_ADDDAYMARKER: u32 = 0x01;
 pub const DC_GCL_VERIFIED_ONLY: usize = 0x01;
 pub const DC_GCL_ADD_SELF: usize = 0x02;
 
+// unchanged user avatars are resent to the recipients every some days
+pub const DC_RESEND_USER_AVATAR_DAYS: i64 = 14;
+
 // values for DC_PARAM_FORCE_PLAINTEXT
 pub(crate) const DC_FP_NO_AUTOCRYPT_HEADER: i32 = 2;
 pub(crate) const DC_FP_ADD_AUTOCRYPT_HEADER: i32 = 1;
@@ -119,6 +122,10 @@ pub const DC_CONTACT_ID_INFO: u32 = 2;
 pub const DC_CONTACT_ID_DEVICE: u32 = 5;
 pub const DC_CONTACT_ID_LAST_SPECIAL: u32 = 9;
 
+// decorative address that is used for DC_CONTACT_ID_DEVICE
+// when an api that returns an email is called.
+pub const DC_CONTACT_ID_DEVICE_ADDR: &str = "device@localhost";
+
 // Flags for empty server job
 
 pub const DC_EMPTY_MVBOX: u32 = 0x01;

src/contact.rs

@@ -168,7 +168,7 @@ impl Contact {
                 .unwrap_or_default();
         } else if contact_id == DC_CONTACT_ID_DEVICE {
             res.name = context.stock_str(StockMessage::DeviceMessages).to_string();
-            res.addr = "device@localhost".to_string();
+            res.addr = DC_CONTACT_ID_DEVICE_ADDR.to_string();
         }
         Ok(res)
     }

src/dc_receive_imf.rs

@@ -897,7 +897,7 @@ fn create_or_lookup_group(
                 );
 
                 mime_parser.is_system_message = SystemMessage::GroupNameChanged;
-            } else if let Some(value) = mime_parser.get(HeaderDef::ChatContent).cloned() {
+            } else if let Some(value) = mime_parser.get(HeaderDef::ChatContent) {
                 if value == "group-avatar-changed" && mime_parser.group_avatar != AvatarAction::None
                 {
                     // this is just an explicit message containing the group-avatar,

test-data/message/mail_with_user_avatar.eml

@@ -23,6 +23,15 @@ Content-Type: image/png
 Content-Disposition: attachment; filename="avatar.png"
 Content-Transfer-Encoding: base64
 
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+wVKHvd493Bzt7+PdPq7wd6nHKqMKZUTAAAAANQTFRF/sYAhYATyAAAAAlwSFlzAAAuIwAALiMBeKU/
+dgAAAAd0SU1FB+MMCBY0D29+N8YAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAA
+AADElEQVQI12NgIA0AAAAwAAHHqoWOAAAAAElFTkSuQmCC
 
 --luTiGu6GBoVLCvTkzVtmZmwsmhkNMw--