feat(lsp): Add codelens support

1 files changed, 231 insertions, 0 deletions

diff --git a/runtime/lua/vim/lsp/codelens.lua b/runtime/lua/vim/lsp/codelens.lua
new file mode 100644
index 0000000000..fbd37e3830
--- /dev/null
+++ b/runtime/lua/vim/lsp/codelens.lua
@@ -0,0 +1,231 @@
+local util = require('vim.lsp.util')
+local api = vim.api
+local M = {}
+
+--- bufnr → true|nil
+--- to throttle refreshes to at most one at a time
+local active_refreshes = {}
+
+--- bufnr -> client_id -> lenses
+local lens_cache_by_buf = setmetatable({}, {
+  __index = function(t, b)
+    local key = b > 0 and b or api.nvim_get_current_buf()
+    return rawget(t, key)
+  end
+})
+
+local namespaces = setmetatable({}, {
+  __index = function(t, key)
+    local value = api.nvim_create_namespace('vim_lsp_codelens:' .. key)
+    rawset(t, key, value)
+    return value
+  end;
+})
+
+--@private
+M.__namespaces = namespaces
+
+
+--@private
+local function execute_lens(lens, bufnr, client_id)
+  local line = lens.range.start.line
+  api.nvim_buf_clear_namespace(bufnr, namespaces[client_id], line, line + 1)
+
+  -- Need to use the client that returned the lens → must not use buf_request
+  local client = vim.lsp.get_client_by_id(client_id)
+  assert(client, 'Client is required to execute lens, client_id=' .. client_id)
+  client.request('workspace/executeCommand', lens.command, function(...)
+    local result = vim.lsp.handlers['workspace/executeCommand'](...)
+    M.refresh()
+    return result
+  end, bufnr)
+end
+
+
+--- Return all lenses for the given buffer
+---
+---@return table (`CodeLens[]`)
+function M.get(bufnr)
+  local lenses_by_client = lens_cache_by_buf[bufnr]
+  if not lenses_by_client then return {} end
+  local lenses = {}
+  for _, client_lenses in pairs(lenses_by_client) do
+    vim.list_extend(lenses, client_lenses)
+  end
+  return lenses
+end
+
+
+--- Run the code lens in the current line
+---
+function M.run()
+  local line = api.nvim_win_get_cursor(0)[1]
+  local bufnr = api.nvim_get_current_buf()
+  local options = {}
+  local lenses_by_client = lens_cache_by_buf[bufnr] or {}
+  for client, lenses in pairs(lenses_by_client) do
+    for _, lens in pairs(lenses) do
+      if lens.range.start.line == (line - 1) then
+        table.insert(options, {client=client, lens=lens})
+      end
+    end
+  end
+  if #options == 0 then
+    vim.notify('No executable codelens found at current line')
+  elseif #options == 1 then
+    local option = options[1]
+    execute_lens(option.lens, bufnr, option.client)
+  else
+    local options_strings = {"Code lenses:"}
+    for i, option in ipairs(options) do
+       table.insert(options_strings, string.format('%d. %s', i, option.lens.command.title))
+    end
+    local choice = vim.fn.inputlist(options_strings)
+    if choice < 1 or choice > #options then
+      return
+    end
+    local option = options[choice]
+    execute_lens(option.lens, bufnr, option.client)
+  end
+end
+
+
+--- Display the lenses using virtual text
+---
+---@param lenses table of lenses to display (`CodeLens[] | null`)
+---@param bufnr number
+---@param client_id number
+function M.display(lenses, bufnr, client_id)
+  if not lenses or not next(lenses) then
+    return
+  end
+  local lenses_by_lnum = {}
+  for _, lens in pairs(lenses) do
+    local line_lenses = lenses_by_lnum[lens.range.start.line]
+    if not line_lenses then
+      line_lenses = {}
+      lenses_by_lnum[lens.range.start.line] = line_lenses
+    end
+    table.insert(line_lenses, lens)
+  end
+  local ns = namespaces[client_id]
+  local num_lines = api.nvim_buf_line_count(bufnr)
+  for i = 0, num_lines do
+    local line_lenses = lenses_by_lnum[i]
+    api.nvim_buf_clear_namespace(bufnr, ns, i, i + 1)
+    local chunks = {}
+    for _, lens in pairs(line_lenses or {}) do
+      local text = lens.command and lens.command.title or 'Unresolved lens ...'
+      table.insert(chunks, {text, 'LspCodeLens' })
+    end
+    if #chunks > 0 then
+      api.nvim_buf_set_virtual_text(bufnr, ns, i, chunks, {})
+    end
+  end
+end
+
+
+--- Store lenses for a specific buffer and client
+---
+---@param lenses table of lenses to store (`CodeLens[] | null`)
+---@param bufnr number
+---@param client_id number
+function M.save(lenses, bufnr, client_id)
+  local lenses_by_client = lens_cache_by_buf[bufnr]
+  if not lenses_by_client then
+    lenses_by_client = {}
+    lens_cache_by_buf[bufnr] = lenses_by_client
+    local ns = namespaces[client_id]
+    api.nvim_buf_attach(bufnr, false, {
+      on_detach = function(b) lens_cache_by_buf[b] = nil end,
+      on_lines = function(_, b, _, first_lnum, last_lnum)
+        api.nvim_buf_clear_namespace(b, ns, first_lnum, last_lnum)
+      end
+    })
+  end
+  lenses_by_client[client_id] = lenses
+end
+
+
+--@private
+local function resolve_lenses(lenses, bufnr, client_id, callback)
+  lenses = lenses or {}
+  local num_lens = vim.tbl_count(lenses)
+  if num_lens == 0 then
+    callback()
+    return
+  end
+
+  --@private
+  local function countdown()
+    num_lens = num_lens - 1
+    if num_lens == 0 then
+      callback()
+    end
+  end
+  local ns = namespaces[client_id]
+  local client = vim.lsp.get_client_by_id(client_id)
+  for _, lens in pairs(lenses or {}) do
+    if lens.command then
+      countdown()
+    else
+      client.request('codeLens/resolve', lens, function(_, _, result)
+        if result and result.command then
+          lens.command = result.command
+          -- Eager display to have some sort of incremental feedback
+          -- Once all lenses got resolved there will be a full redraw for all lenses
+          -- So that multiple lens per line are properly displayed
+          api.nvim_buf_set_virtual_text(
+            bufnr,
+            ns,
+            lens.range.start.line,
+            {{ lens.command.title, 'LspCodeLens' },},
+            {}
+          )
+        end
+        countdown()
+      end, bufnr)
+    end
+  end
+end
+
+
+--- |lsp-handler| for the method `textDocument/codeLens`
+---
+function M.on_codelens(err, _, result, client_id, bufnr)
+  assert(not err, vim.inspect(err))
+
+  M.save(result, bufnr, client_id)
+
+  -- Eager display for any resolved (and unresolved) lenses and refresh them
+  -- once resolved.
+  M.display(result, bufnr, client_id)
+  resolve_lenses(result, bufnr, client_id, function()
+    M.display(result, bufnr, client_id)
+    active_refreshes[bufnr] = nil
+  end)
+end
+
+
+--- Refresh the codelens for the current buffer
+---
+--- It is recommended to trigger this using an autocmd or via keymap.
+---
+--- <pre>
+---   autocmd BufEnter,CursorHold,InsertLeave <buffer> lua vim.lsp.codelens.refresh()
+--- </pre>
+---
+function M.refresh()
+  local params = {
+    textDocument = util.make_text_document_params()
+  }
+  local bufnr = api.nvim_get_current_buf()
+  if active_refreshes[bufnr] then
+    return
+  end
+  active_refreshes[bufnr] = true
+  vim.lsp.buf_request(0, 'textDocument/codeLens', params)
+end
+
+
+return M