1 files changed, 55 insertions, 3 deletions

diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index b7c7b7f75d..21e0dbfd1f 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -269,7 +269,7 @@ function M.convert_input_to_markdown_lines(input, contents)
       end
     end
   end
-  if contents[1] == '' or contents[1] == nil then
+  if (contents[1] == '' or contents[1] == nil) and #contents == 1 then
     return {}
   end
   return contents
@@ -569,7 +569,8 @@ do
   local all_buffer_diagnostics = {}
 
   local diagnostic_ns = api.nvim_create_namespace("vim_lsp_diagnostics")
-
+  local reference_ns = api.nvim_create_namespace("vim_lsp_references")
+  local sign_ns = 'vim_lsp_signs'
   local underline_highlight_name = "LspDiagnosticsUnderline"
   vim.cmd(string.format("highlight default %s gui=underline cterm=underline", underline_highlight_name))
   for kind, _ in pairs(protocol.DiagnosticSeverity) do
@@ -603,6 +604,11 @@ do
   function M.buf_clear_diagnostics(bufnr)
     validate { bufnr = {bufnr, 'n', true} }
     bufnr = bufnr == 0 and api.nvim_get_current_buf() or bufnr
+
+    -- clear sign group
+    vim.fn.sign_unplace(sign_ns, {buffer=bufnr})
+
+    -- clear virtual text namespace
     api.nvim_buf_clear_namespace(bufnr, diagnostic_ns, 0, -1)
   end
 
@@ -683,7 +689,6 @@ do
     end
   end
 
-
   function M.buf_diagnostics_underline(bufnr, diagnostics)
     for _, diagnostic in ipairs(diagnostics) do
       local start = diagnostic.range["start"]
@@ -705,6 +710,25 @@ do
     end
   end
 
+  function M.buf_clear_references(bufnr)
+    validate { bufnr = {bufnr, 'n', true} }
+    api.nvim_buf_clear_namespace(bufnr, reference_ns, 0, -1)
+  end
+
+  function M.buf_highlight_references(bufnr, references)
+    validate { bufnr = {bufnr, 'n', true} }
+    for _, reference in ipairs(references) do
+      local start_pos = {reference["range"]["start"]["line"], reference["range"]["start"]["character"]}
+      local end_pos = {reference["range"]["end"]["line"], reference["range"]["end"]["character"]}
+      local document_highlight_kind = {
+        [protocol.DocumentHighlightKind.Text] = "LspReferenceText";
+        [protocol.DocumentHighlightKind.Read] = "LspReferenceRead";
+        [protocol.DocumentHighlightKind.Write] = "LspReferenceWrite";
+      }
+      highlight_range(bufnr, reference_ns, document_highlight_kind[reference["kind"]], start_pos, end_pos)
+    end
+  end
+
   function M.buf_diagnostics_virtual_text(bufnr, diagnostics)
     local buffer_line_diagnostics = all_buffer_diagnostics[bufnr]
     if not buffer_line_diagnostics then
@@ -725,6 +749,34 @@ do
       api.nvim_buf_set_virtual_text(bufnr, diagnostic_ns, line, virt_texts, {})
     end
   end
+  function M.buf_diagnostics_count(kind)
+    local bufnr = vim.api.nvim_get_current_buf()
+    local buffer_line_diagnostics = all_buffer_diagnostics[bufnr]
+    if not buffer_line_diagnostics then return end
+    local count = 0
+    for _, line_diags in pairs(buffer_line_diagnostics) do
+      for _, diag in ipairs(line_diags) do
+        if protocol.DiagnosticSeverity[kind] == diag.severity then count = count + 1 end
+      end
+    end
+    return count
+  end
+  function M.buf_diagnostics_signs(bufnr, diagnostics)
+    vim.fn.sign_define('LspDiagnosticsErrorSign', {text=vim.g['LspDiagnosticsErrorSign'] or 'E', texthl='LspDiagnosticsError', linehl='', numhl=''})
+    vim.fn.sign_define('LspDiagnosticsWarningSign', {text=vim.g['LspDiagnosticsWarningSign'] or 'W', texthl='LspDiagnosticsWarning', linehl='', numhl=''})
+    vim.fn.sign_define('LspDiagnosticsInformationSign', {text=vim.g['LspDiagnosticsInformationSign'] or 'I', texthl='LspDiagnosticsInformation', linehl='', numhl=''})
+    vim.fn.sign_define('LspDiagnosticsHintSign', {text=vim.g['LspDiagnosticsHintSign'] or 'H', texthl='LspDiagnosticsHint', linehl='', numhl=''})
+
+    for _, diagnostic in ipairs(diagnostics) do
+      local diagnostic_severity_map = {
+        [protocol.DiagnosticSeverity.Error] = "LspDiagnosticsErrorSign";
+        [protocol.DiagnosticSeverity.Warning] = "LspDiagnosticsWarningSign";
+        [protocol.DiagnosticSeverity.Information] = "LspDiagnosticsInformationSign";
+        [protocol.DiagnosticSeverity.Hint] = "LspDiagnosticsHintSign";
+      }
+      vim.fn.sign_place(0, sign_ns, diagnostic_severity_map[diagnostic.severity], bufnr, {lnum=(diagnostic.range.start.line+1)})
+    end
+  end
 end
 
 local position_sort = sort_by_key(function(v)