Add support for documentHighlight in vim8

autoload/LanguageClient.vim

@@ -290,6 +290,11 @@ function! s:MatchDelete(ids) abort
 endfunction
 
 function! s:ApplySemanticHighlights(bufnr, ns_id, clears, highlights) abort
+    " TODO: implement this for vim8
+    if !has('nvim')
+      return
+    endif
+
     for clear in a:clears
         call nvim_buf_clear_namespace(a:bufnr, a:ns_id, clear.line_start, clear.line_end)
     endfor
@@ -300,10 +305,45 @@ function! s:ApplySemanticHighlights(bufnr, ns_id, clears, highlights) abort
 endfunction
 
 " Batch version of nvim_buf_add_highlight
-function! s:AddHighlights(source, highlights) abort
+function! s:AddHighlights(namespace_id, highlights) abort
+  if has('nvim')
+    for hl in a:highlights
+        call nvim_buf_add_highlight(0, a:namespace_id, hl.group, hl.line, hl.character_start, hl.character_end)
+    endfor
+  else
+    let match_ids = []
     for hl in a:highlights
-        call nvim_buf_add_highlight(0, a:source, hl.group, hl.line, hl.character_start, hl.character_end)
+      let match_id = matchaddpos(hl.group, [[hl.line + 1, hl.character_start + 1, hl.character_end - hl.character_start]])
+      let match_ids = add(match_ids, match_id)
+    endfor
+
+    call setbufvar(bufname(), 'document_highlight_match_ids', match_ids)
+  endif
+endfunction
+
+function! s:SetHighlights(highlights) abort
+  call s:ClearHighlights()
+  if has('nvim')
+    let s:namespace_id = nvim_create_namespace('__LCN_DOCUMENT_HIGHLIGHTS__')
+    call s:AddHighlights(s:namespace_id, a:highlights)
+  else
+    call s:AddHighlights(0, a:highlights)
+  endif
+endfunction
+
+function! s:ClearHighlights() abort
+  if has('nvim')
+    let s:namespace_id = nvim_create_namespace('__LCN_DOCUMENT_HIGHLIGHTS__')
+    call nvim_buf_clear_namespace(0, s:namespace_id, 0, -1)
+  else
+    let match_ids = get(b:, 'document_highlight_match_ids', [])
+    for mid in match_ids
+      " call inside a try/catch to avoid error for manually cleared matches
+      try | call matchdelete(mid) | catch
+      endtry
     endfor
+    call setbufvar(bufname(), 'document_highlight_match_ids', [])
+  endif
 endfunction
 
 " Get an variable value.

src/language_server_protocol.rs

@@ -1,7 +1,7 @@
 use crate::language_client::LanguageClient;
 use crate::sign::Sign;
 use crate::vim::{try_get, Mode};
-use crate::{extensions::java, viewport::Viewport};
+use crate::{extensions::java, viewport::Viewport, vim::Highlight};
 use crate::{
     rpcclient::RpcClient,
     types::*,
@@ -508,74 +508,15 @@ impl LanguageClient {
                 })
                 .collect::<Result<Vec<_>>>()?;
 
-            let buffer = self.vim()?.get_bufnr(&filename, params)?;
-
-            // The following code needs to be inside the critical section as a whole to update
-            // everything correctly and not leave hanging highlights.
-            self.update(|state| {
-                let source = if let Some(hs) = state.document_highlight_source {
-                    if hs.buffer == buffer {
-                        // If we want to highlight in the same buffer as last time, we can reuse
-                        // the previous source.
-                        Some(hs.source)
-                    } else {
-                        // Clear the highlight in the previous buffer.
-                        state.vim.rpcclient.notify(
-                            "nvim_buf_clear_highlight",
-                            json!([hs.buffer, hs.source, 0, -1]),
-                        )?;
-
-                        None
-                    }
-                } else {
-                    None
-                };
-
-                let source = match source {
-                    Some(source) => source,
-                    None => {
-                        // Create a new source.
-                        let source = state.vim.rpcclient.call(
-                            "nvim_buf_add_highlight",
-                            json!([buffer, 0, "Error", 1, 1, 1]),
-                        )?;
-                        state.document_highlight_source = Some(HighlightSource { buffer, source });
-                        source
-                    }
-                };
-
-                state
-                    .vim
-                    .rpcclient
-                    .notify("nvim_buf_clear_highlight", json!([buffer, source, 0, -1]))?;
-                state
-                    .vim
-                    .rpcclient
-                    .notify("s:AddHighlights", json!([source, highlights]))?;
-
-                Ok(())
-            })?;
+            self.vim()?.set_highlights(&highlights)?;
         }
 
         Ok(result)
     }
 
     #[tracing::instrument(level = "info", skip(self))]
     pub fn clear_document_highlight(&self, _params: &Value) -> Result<()> {
-        // The following code needs to be inside the critical section as a whole to update
-        // everything correctly and not leave hanging highlights.
-        self.update(|state| {
-            if let Some(HighlightSource { buffer, source }) = state.document_highlight_source.take()
-            {
-                state
-                    .vim
-                    .rpcclient
-                    .notify("nvim_buf_clear_highlight", json!([buffer, source, 0, -1]))?;
-            }
-            Ok(())
-        })?;
-
-        Ok(())
+        self.vim()?.clear_highlights()
     }
 
     #[tracing::instrument(level = "info", skip(self))]
@@ -3139,41 +3080,7 @@ impl LanguageClient {
                 .collect())
         })?;
 
-        if Some(highlights.clone())
-            != self.get(|state| state.highlights_placed.get(&filename).cloned())?
-            && self.get(|state| state.is_nvim)?
-        {
-            let source = if let Some(source) = self.get(|state| state.highlight_source)? {
-                source
-            } else {
-                let source = self
-                    .vim()?
-                    .rpcclient
-                    .call("nvim_buf_add_highlight", json!([0, 0, "Error", 1, 1, 1]))?;
-                self.update(|state| {
-                    state.highlight_source = Some(source);
-                    Ok(())
-                })?;
-                source
-            };
-
-            self.update(|state| {
-                state
-                    .highlights_placed
-                    .insert(filename.clone(), highlights.clone());
-                Ok(())
-            })?;
-
-            self.vim()?.rpcclient.notify(
-                "nvim_buf_clear_highlight",
-                json!([0, source, current_viewport.start, current_viewport.end]),
-            )?;
-
-            self.vim()?
-                .rpcclient
-                .notify("s:AddHighlights", json!([source, highlights]))?;
-        }
-
+        self.vim()?.set_highlights(&highlights)?;
         self.draw_virtual_texts(&params)?;
 
         Ok(())

src/types.rs

@@ -5,7 +5,7 @@ use crate::{
     vim::Vim,
     watcher::FSWatch,
 };
-use crate::{logger::Logger, viewport::Viewport};
+use crate::{logger::Logger, viewport::Viewport, vim::Highlight};
 use anyhow::{anyhow, Result};
 use jsonrpc_core::Params;
 use log::*;
@@ -119,12 +119,6 @@ pub enum Call {
     Notification(LanguageId, jsonrpc_core::Notification),
 }
 
-#[derive(Clone, Copy, Serialize)]
-pub struct HighlightSource {
-    pub buffer: Bufnr,
-    pub source: u64,
-}
-
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum UseVirtualText {
     Diagnostics,
@@ -169,7 +163,6 @@ pub struct State {
     pub highlights_placed: HashMap<String, Vec<Highlight>>,
     // TODO: make file specific.
     pub highlight_match_ids: Vec<u32>,
-    pub document_highlight_source: Option<HighlightSource>,
     pub user_handlers: HashMap<String, String>,
     #[serde(skip_serializing)]
     pub watchers: HashMap<String, FSWatch>,
@@ -259,7 +252,6 @@ impl State {
             highlights: HashMap::new(),
             highlights_placed: HashMap::new(),
             highlight_match_ids: Vec::new(),
-            document_highlight_source: None,
             user_handlers: HashMap::new(),
             watchers: HashMap::new(),
             watcher_rxs: HashMap::new(),
@@ -506,22 +498,6 @@ pub struct TextDocumentSemanticHighlightState {
     pub highlights: Option<Vec<Highlight>>,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct Highlight {
-    pub line: u64,
-    pub character_start: u64,
-    pub character_end: u64,
-    pub group: String,
-    pub text: String,
-}
-
-impl PartialEq for Highlight {
-    fn eq(&self, other: &Self) -> bool {
-        // Quick check whether highlight should be updated.
-        self.text == other.text && self.group == other.group
-    }
-}
-
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ClearNamespace {
     pub line_start: u64,

src/vim.rs

@@ -1,5 +1,5 @@
-use crate::rpcclient::RpcClient;
 use crate::{
+    rpcclient::RpcClient,
     sign::Sign,
     types::{Bufnr, QuickfixEntry, VimExp, VirtualText},
     utils::Canonicalize,
@@ -23,6 +23,21 @@ pub fn try_get<'a, R: Deserialize<'a>>(key: &str, params: &'a Value) -> Result<O
     }
 }
 
+#[derive(Clone, Copy, Serialize)]
+pub struct HighlightSource {
+    pub buffer: Bufnr,
+    pub source: u64,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Highlight {
+    pub line: u64,
+    pub character_start: u64,
+    pub character_end: u64,
+    pub group: String,
+    pub text: String,
+}
+
 #[derive(PartialEq)]
 pub enum Mode {
     Normal,
@@ -223,6 +238,21 @@ impl Vim {
         Ok(())
     }
 
+    /// clears all highlights in the current buffer.
+    pub fn clear_highlights(&self) -> Result<()> {
+        self.rpcclient.notify("s:ClearHighlights", json!([]))
+    }
+
+    /// replaces the highlights of the current document with the passed highlights.
+    pub fn set_highlights(&self, highlights: &[Highlight]) -> Result<()> {
+        if highlights.is_empty() {
+            return Ok(());
+        }
+
+        self.rpcclient
+            .notify("s:SetHighlights", json!([highlights]))
+    }
+
     pub fn create_namespace(&self, name: &str) -> Result<i64> {
         self.rpcclient.call("nvim_create_namespace", [name])
     }