From 82c7f0818a688013d1266f2847657dc3054d468f Mon Sep 17 00:00:00 2001
From: daa <andrey.dubravin@gmail.com>
Date: Sat, 31 Mar 2018 19:56:44 +0300
Subject: [PATCH] Prevent popup blink in case events hide/show come together

---
 src/nvim/handler.rs        |  4 +++-
 src/nvim/redraw_handler.rs | 45 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/src/nvim/handler.rs b/src/nvim/handler.rs
index c6ee331..3c62eae 100644
--- a/src/nvim/handler.rs
+++ b/src/nvim/handler.rs
@@ -19,9 +19,11 @@ impl NvimHandler {
         NvimHandler { shell: shell }
     }
 
-    fn nvim_cb(&self, method: &str, params: Vec<Value>) {
+    fn nvim_cb(&self, method: &str, mut params: Vec<Value>) {
         match method {
             "redraw" => {
+                redraw_handler::remove_uneeded_events(&mut params);
+
                 self.safe_call(move |ui| {
                     let ui = &mut ui.borrow_mut();
                     let mut repaint_mode = RepaintMode::Nothing;
diff --git a/src/nvim/redraw_handler.rs b/src/nvim/redraw_handler.rs
index bef2e3f..f82d55b 100644
--- a/src/nvim/redraw_handler.rs
+++ b/src/nvim/redraw_handler.rs
@@ -116,7 +116,7 @@ pub fn call_gui_event(
         },
         "Command" => {
             ui.on_command(args);
-        },
+        }
         _ => return Err(format!("Unsupported event {}({:?})", method, args)),
     }
     Ok(())
@@ -247,6 +247,30 @@ pub fn call(
     Ok(repaint_mode)
 }
 
+// menu content update call popupmenu_hide followed by popupmenu_show
+// this generates unneded hide event
+// so in case we get both events, just romove one
+pub fn remove_uneeded_events(params: &mut Vec<Value>) {
+    let mut show_popup_finded = false;
+    let mut to_remove = Vec::new();
+
+    for (idx, val) in params.iter().enumerate().rev() {
+        if let Some(args) = val.as_array() {
+            match args[0].as_str() {
+                Some("popupmenu_show") => show_popup_finded = true,
+                Some("popupmenu_hide") if show_popup_finded => {
+                    to_remove.push(idx);
+                }
+                _ => (),
+            }
+        }
+    }
+
+    to_remove.iter().for_each(|&idx| {
+        params.remove(idx);
+    });
+}
+
 pub struct CompleteItem<'a> {
     pub word: &'a str,
     pub kind: &'a str,
@@ -266,3 +290,22 @@ impl<'a> CompleteItem<'a> {
             .collect()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_remove_popup_menu_hide() {
+        // remove only first hide
+        let mut params = vec![
+            Value::from(vec![Value::from("popupmenu_hide")]),
+            Value::from(vec![Value::from("popupmenu_show")]),
+            Value::from(vec![Value::from("popupmenu_hide")]),
+        ];
+
+        remove_uneeded_events(&mut params);
+
+        assert_eq!(2, params.len());
+    }
+}