Merge pull request #1771 from deltachat/summary-from-context

add dc_chatlist_get_summary2() api

deltachat-ffi/deltachat.h

@@ -2470,6 +2470,28 @@ uint32_t         dc_chatlist_get_msg_id      (const dc_chatlist_t* chatlist, siz
 dc_lot_t*        dc_chatlist_get_summary     (const dc_chatlist_t* chatlist, size_t index, dc_chat_t* chat);
 
 
+/**
+ * Create a chatlist summary item when the chatlist object is already unref()'d.
+ *
+ * This function is similar to dc_chatlist_get_summary(), however,
+ * takes the chat-id and message-id as returned by dc_chatlist_get_chat_id() and dc_chatlist_get_msg_id()
+ * as arguments. The chatlist object itself is not needed directly.
+ *
+ * This maybe useful if you convert the complete object into a different represenation
+ * as done eg. in the node-bindings.
+ * If you have access to the chatlist object in some way, using this function is not recommended,
+ * use dc_chatlist_get_summary() in this case instead.
+ *
+ * @memberof dc_context_t
+ * @param context The context as created by dc_context_new()
+ * @param chat_id Chat to get a summary for.
+ * @param msg_id Messasge to get a summary for.
+ * @return The summary as an dc_lot_t object, see dc_chatlist_get_summary() for details.
+ *     Must be freed using dc_lot_unref().  NULL is never returned.
+ */
+dc_lot_t*        dc_chatlist_get_summary2    (dc_context_t* context, uint32_t chat_id, uint32_t msg_id);
+
+
 /**
  * Helper function to get the associated context object.
  *

deltachat-ffi/src/lib.rs

@@ -38,6 +38,7 @@ mod dc_array;
 
 mod string;
 use self::string::*;
+use deltachat::chatlist::Chatlist;
 
 // as C lacks a good and portable error handling,
 // in general, the C Interface is forgiving wrt to bad parameters.
@@ -2227,6 +2228,24 @@ pub unsafe extern "C" fn dc_chatlist_get_summary(
     })
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_chatlist_get_summary2(
+    context: *mut dc_context_t,
+    chat_id: u32,
+    msg_id: u32,
+) -> *mut dc_lot_t {
+    if context.is_null() {
+        eprintln!("ignoring careless call to dc_chatlist_get_summary2()");
+        return ptr::null_mut();
+    }
+    let ctx = &*context;
+    block_on(async move {
+        let lot =
+            Chatlist::get_summary2(&ctx, ChatId::new(chat_id), MsgId::new(msg_id), None).await;
+        Box::into_raw(Box::new(lot))
+    })
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn dc_chatlist_get_context(
     chatlist: *mut dc_chatlist_t,

src/chatlist.rs

@@ -329,20 +329,30 @@ impl Chatlist {
         // This is because we may want to display drafts here or stuff as
         // "is typing".
         // Also, sth. as "No messages" would not work if the summary comes from a message.
-        let mut ret = Lot::new();
-
         let (chat_id, lastmsg_id) = match self.ids.get(index) {
             Some(ids) => ids,
             None => {
+                let mut ret = Lot::new();
                 ret.text2 = Some("ErrBadChatlistIndex".to_string());
-                return ret;
+                return Lot::new();
             }
         };
 
+        Chatlist::get_summary2(context, *chat_id, *lastmsg_id, chat).await
+    }
+
+    pub async fn get_summary2(
+        context: &Context,
+        chat_id: ChatId,
+        lastmsg_id: MsgId,
+        chat: Option<&Chat>,
+    ) -> Lot {
+        let mut ret = Lot::new();
+
         let chat_loaded: Chat;
         let chat = if let Some(chat) = chat {
             chat
-        } else if let Ok(chat) = Chat::load_from_db(context, *chat_id).await {
+        } else if let Ok(chat) = Chat::load_from_db(context, chat_id).await {
             chat_loaded = chat;
             &chat_loaded
         } else {
@@ -351,7 +361,7 @@ impl Chatlist {
 
         let mut lastcontact = None;
 
-        let lastmsg = if let Ok(lastmsg) = Message::load_from_db(context, *lastmsg_id).await {
+        let lastmsg = if let Ok(lastmsg) = Message::load_from_db(context, lastmsg_id).await {
             if lastmsg.from_id != DC_CONTACT_ID_SELF
                 && (chat.typ == Chattype::Group || chat.typ == Chattype::VerifiedGroup)
             {