add dc_msg_get_info_type() to allow drawing a shield in the uis

deltachat-ffi/deltachat.h

@@ -3477,6 +3477,32 @@ int             dc_msg_is_forwarded           (const dc_msg_t* msg);
 int             dc_msg_is_info                (const dc_msg_t* msg);
 
 
+/**
+ * Get the type of an informational message.
+ * If dc_msg_is_info() returns 1, this function returns the type of the informational message.
+ * UIs can display eg. an icon based upon the type.
+ *
+ * Currently, the following types are defined:
+ * - DC_INFO_PROTECTION_ENABLED (11) - Info-message for "Chat is now protected"
+ * - DC_INFO_PROTECTION_DISABLED (12) - Info-message for "Chat is no longer protected"
+ *
+ * Even when you display an icon,
+ * you should still display the text of the informational message using dc_msg_get_text()
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @return One of the DC_INFO* constants.
+ *     0 or other values indicate unspecified types
+ *     or that the message is not an info-message.
+ */
+int             dc_msg_get_info_type          (const dc_msg_t* msg);
+
+
+// DC_INFO* uses the same values as SystemMessage in rust-land
+#define         DC_INFO_PROTECTION_ENABLED     11
+#define         DC_INFO_PROTECTION_DISABLED    12
+
+
 /**
  * Check if a message is still in creation.  A message is in creation between
  * the calls to dc_prepare_msg() and dc_send_msg().

deltachat-ffi/src/lib.rs

@@ -2843,6 +2843,16 @@ pub unsafe extern "C" fn dc_msg_is_info(msg: *mut dc_msg_t) -> libc::c_int {
     ffi_msg.message.is_info().into()
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_info_type(msg: *mut dc_msg_t) -> libc::c_int {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_get_info_type()");
+        return 0;
+    }
+    let ffi_msg = &*msg;
+    ffi_msg.message.get_info_type() as libc::c_int
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn dc_msg_is_increation(msg: *mut dc_msg_t) -> libc::c_int {
     if msg.is_null() {

src/message.rs

@@ -589,6 +589,10 @@ impl Message {
             || cmd != SystemMessage::Unknown && cmd != SystemMessage::AutocryptSetupMessage
     }
 
+    pub fn get_info_type(&self) -> SystemMessage {
+        self.param.get_cmd()
+    }
+
     pub fn is_system_message(&self) -> bool {
         let cmd = self.param.get_cmd();
         cmd != SystemMessage::Unknown