Add rudimentry tracking to not return data before the line changed

Author: alerque

lua/commonmarker/init.lua

@@ -37,7 +37,8 @@ end
 
 local function highlight (buffer, namespace, firstline)
 	local contents = get_contents(buffer)
-	local events = rust.get_offsets(contents)
+	local firstbyte = call_function("line2byte", { firstline })
+	local events = rust.get_offsets(contents, firstbyte)
 	for _, event in ipairs(events) do
 		repeat -- Allow continue in for loop
 			local sline, scol = byte2pos(event.first)

src/lib.rs

@@ -27,14 +27,17 @@ struct MdTag {
 
 type Events = Vec<MdTag>;
 
-fn get_offsets(buffer: String) -> Result<Events> {
+fn get_offsets(buffer: String, firstbyte: usize) -> Result<Events> {
     let options = Options::all();
     let parser = Parser::new_ext(buffer.as_str(), options);
     let mut events = Events::new();
     for (event, range) in parser.into_offset_iter() {
         let first = range.start + 1;
         let last = range.end + 1;
         let mut lang = None;
+        if first < firstbyte {
+            continue;
+        }
         let group = match event {
             Event::Start(tag) => match tag {
                 Tag::Heading(level) => Some(format!("cmarkHeading{}", level)),

src/lua.rs

@@ -5,9 +5,9 @@ fn to_html(_: &Lua, buffer: String) -> LuaResult<String> {
     Ok(super::to_html(buffer).unwrap())
 }
 
-fn get_offsets(lua: &Lua, buffer: String) -> LuaResult<LuaTable> {
+fn get_offsets(lua: &Lua, (buffer, firstbyte): (String, usize)) -> LuaResult<LuaTable> {
     let table = lua.create_table().unwrap();
-    let events = super::get_offsets(buffer).unwrap();
+    let events = super::get_offsets(buffer, firstbyte).unwrap();
     for (i, event) in events.iter().enumerate() {
         let info = lua.create_table().unwrap();
         info.set("group", event.group.as_str()).unwrap();

src/python.rs

@@ -8,8 +8,8 @@ fn to_html(_py: Python, buffer: String) -> PyResult<String> {
 }
 
 #[pyfunction]
-fn get_offsets(_py: Python, buffer: String) -> PyResult<&PyDict> {
-    let events = super::get_offsets(buffer).unwrap();
+fn get_offsets(_py: Python, buffer: String, firstbyte: usize) -> PyResult<&PyDict> {
+    let events = super::get_offsets(buffer, firstbyte).unwrap();
     let pyevents = PyDict::new(_py);
     let mut i: u32 = 1;
     for event in events.iter() {