feat(refactor): highlight usages module

lua/nvim-treesitter/refactor/highlight_definitions.lua

@@ -0,0 +1,93 @@
+-- This module highlights reference usages and the corresponding
+-- definition on cursor hold.
+
+local parsers = require'nvim-treesitter.parsers'
+local ts_utils = require'nvim-treesitter.ts_utils'
+local locals = require'nvim-treesitter.locals'
+local api = vim.api
+local cmd = api.nvim_command
+
+local M = {}
+
+local usage_namespace = api.nvim_create_namespace('nvim-treesitter-usages')
+
+local function find_usages(node, scope_node)
+  local usages = {}
+  local node_text = ts_utils.get_node_text(node)[1]
+
+  if not node_text or #node_text < 1 then return end
+
+  for _, def in ipairs(locals.collect_locals(bufnr, scope_node)) do
+    if def.reference 
+      and def.reference.node 
+      and ts_utils.get_node_text(def.reference.node)[1] == node_text then
+      
+      table.insert(usages, def.reference.node)
+    end
+  end
+
+  return usages
+end
+
+function M.highlight_usages(bufnr)
+  M.clear_usage_highlights(bufnr)
+
+  local node_at_point = ts_utils.get_node_at_cursor()
+
+  if not node_at_point then return end
+
+  local def_node, scope = ts_utils.find_definition(node_at_point, bufnr)
+  local usages = find_usages(node_at_point, scope)
+
+  for _, usage_node in ipairs(usages) do
+    local start_row, start_col, _, end_col = usage_node:range()
+
+    if usage_node ~= node_at_point then
+      api.nvim_buf_add_highlight(
+        bufnr, 
+        usage_namespace, 
+        'Visual', 
+        start_row,
+        start_col,
+        end_col)
+    end
+  end
+
+  if def_node then
+    local start_row, start_col, _, end_col = def_node:range()
+
+    if def_node ~= node_at_point then
+      api.nvim_buf_add_highlight(
+        bufnr, 
+        usage_namespace, 
+        'Search', 
+        start_row,
+        start_col,
+        end_col)
+    end
+  end
+end
+
+function M.clear_usage_highlights(bufnr)
+  api.nvim_buf_clear_namespace(bufnr, usage_namespace, 0, -1)
+end
+
+function M.attach(bufnr)
+  local bufnr = bufnr or api.nvim_get_current_buf()
+
+  cmd(string.format('augroup NvimTreesitterUsages_%d', bufnr))
+  cmd 'au!'
+  cmd(string.format([[autocmd CursorHold <buffer=%d> lua require'nvim-treesitter.refactor.highlight_definitions'.highlight_usages(%d)]], bufnr, bufnr))
+  cmd(string.format([[autocmd CursorMoved <buffer=%d> lua require'nvim-treesitter.refactor.highlight_definitions'.clear_usage_highlights(%d)]], bufnr, bufnr))
+  cmd(string.format([[autocmd InsertEnter <buffer=%d> lua require'nvim-treesitter.refactor.highlight_definitions'.clear_usage_highlights(%d)]], bufnr, bufnr))
+  cmd 'augroup END'
+end
+
+function M.detach(bufnr)
+  M.clear_usage_highlights(bufnr)
+  cmd(string.format('autocmd! NvimTreesitterUsages_%d CursorHold', bufnr))
+  cmd(string.format('autocmd! NvimTreesitterUsages_%d CursorMoved', bufnr))
+  cmd(string.format('autocmd! NvimTreesitterUsages_%d InsertEnter', bufnr))
+end
+
+return M