feat(lsp): move inlay_hint() to vim.lsp (#24130)

Allows to keep more functions hidden and gives a path forward for
further inlay_hint related functions - like applying textEdits.

See https://github.com/neovim/neovim/pull/23984#pullrequestreview-1486624668

1 files changed, 313 insertions, 0 deletions

diff --git a/runtime/lua/vim/lsp/inlay_hint.lua b/runtime/lua/vim/lsp/inlay_hint.lua
new file mode 100644
index 0000000000..1af18bbc61
--- /dev/null
+++ b/runtime/lua/vim/lsp/inlay_hint.lua
@@ -0,0 +1,313 @@
+local util = require('vim.lsp.util')
+local log = require('vim.lsp.log')
+local api = vim.api
+local M = {}
+
+---@class lsp._inlay_hint.bufstate
+---@field version integer
+---@field client_hint table<integer, table<integer, lsp.InlayHint[]>> client_id -> (lnum -> hints)
+---@field enabled boolean Whether inlay hints are enabled for the buffer
+---@field timer uv.uv_timer_t? Debounce timer associated with the buffer
+---@field applied table<integer, integer> Last version of hints applied to this line
+
+---@type table<integer, lsp._inlay_hint.bufstate>
+local bufstates = {}
+
+local namespace = api.nvim_create_namespace('vim_lsp_inlayhint')
+local augroup = api.nvim_create_augroup('vim_lsp_inlayhint', {})
+
+--- Reset the request debounce timer of a buffer
+---@private
+local function reset_timer(reset_bufnr)
+  local timer = bufstates[reset_bufnr].timer
+  if timer then
+    bufstates[reset_bufnr].timer = nil
+    if not timer:is_closing() then
+      timer:stop()
+      timer:close()
+    end
+  end
+end
+
+--- |lsp-handler| for the method `textDocument/inlayHint`
+--- Store hints for a specific buffer and client
+---@private
+function M.on_inlayhint(err, result, ctx, _)
+  if err then
+    local _ = log.error() and log.error('inlayhint', err)
+    return
+  end
+  local bufnr = ctx.bufnr
+  if util.buf_versions[bufnr] ~= ctx.version then
+    return
+  end
+  local client_id = ctx.client_id
+  if not result then
+    return
+  end
+  local bufstate = bufstates[bufnr]
+  if not (bufstate.client_hint and bufstate.version) then
+    bufstate.client_hint = vim.defaulttable()
+    bufstate.version = ctx.version
+  end
+  local hints_by_client = bufstate.client_hint
+  local client = vim.lsp.get_client_by_id(client_id)
+
+  local new_hints_by_lnum = vim.defaulttable()
+  local num_unprocessed = #result
+  if num_unprocessed == 0 then
+    hints_by_client[client_id] = {}
+    bufstate.version = ctx.version
+    api.nvim__buf_redraw_range(bufnr, 0, -1)
+    return
+  end
+
+  local lines = api.nvim_buf_get_lines(bufnr, 0, -1, false)
+  ---@private
+  local function pos_to_byte(position)
+    local col = position.character
+    if col > 0 then
+      local line = lines[position.line + 1] or ''
+      local ok, convert_result
+      ok, convert_result = pcall(util._str_byteindex_enc, line, col, client.offset_encoding)
+      if ok then
+        return convert_result
+      end
+      return math.min(#line, col)
+    end
+    return col
+  end
+
+  for _, hint in ipairs(result) do
+    local lnum = hint.position.line
+    hint.position.character = pos_to_byte(hint.position)
+    table.insert(new_hints_by_lnum[lnum], hint)
+  end
+
+  hints_by_client[client_id] = new_hints_by_lnum
+  bufstate.version = ctx.version
+  api.nvim__buf_redraw_range(bufnr, 0, -1)
+end
+
+---@private
+local function resolve_bufnr(bufnr)
+  return bufnr > 0 and bufnr or api.nvim_get_current_buf()
+end
+
+--- Refresh inlay hints for a buffer
+---
+---@param opts (nil|table) Optional arguments
+---  - bufnr (integer, default: 0): Buffer whose hints to refresh
+---  - only_visible (boolean, default: false): Whether to only refresh hints for the visible regions of the buffer
+---
+---@private
+local function refresh(opts)
+  opts = opts or {}
+  local bufnr = resolve_bufnr(opts.bufnr or 0)
+  local bufstate = bufstates[bufnr]
+  if not (bufstate and bufstate.enabled) then
+    return
+  end
+  local only_visible = opts.only_visible or false
+  local buffer_windows = {}
+  for _, winid in ipairs(api.nvim_list_wins()) do
+    if api.nvim_win_get_buf(winid) == bufnr then
+      table.insert(buffer_windows, winid)
+    end
+  end
+  for _, window in ipairs(buffer_windows) do
+    local first = vim.fn.line('w0', window)
+    local last = vim.fn.line('w$', window)
+    local params = {
+      textDocument = util.make_text_document_params(bufnr),
+      range = {
+        start = { line = first - 1, character = 0 },
+        ['end'] = { line = last, character = 0 },
+      },
+    }
+    vim.lsp.buf_request(bufnr, 'textDocument/inlayHint', params)
+  end
+  if not only_visible then
+    local params = {
+      textDocument = util.make_text_document_params(bufnr),
+      range = {
+        start = { line = 0, character = 0 },
+        ['end'] = { line = api.nvim_buf_line_count(bufnr), character = 0 },
+      },
+    }
+    vim.lsp.buf_request(bufnr, 'textDocument/inlayHint', params)
+  end
+end
+
+--- |lsp-handler| for the method `textDocument/inlayHint/refresh`
+---@private
+function M.on_refresh(err, _, ctx, _)
+  if err then
+    return vim.NIL
+  end
+  for _, bufnr in ipairs(vim.lsp.get_buffers_by_client_id(ctx.client_id)) do
+    for _, winid in ipairs(api.nvim_list_wins()) do
+      if api.nvim_win_get_buf(winid) == bufnr then
+        refresh({ bufnr = bufnr })
+        break
+      end
+    end
+  end
+
+  return vim.NIL
+end
+
+--- Clear inlay hints
+---@param bufnr (integer) Buffer handle, or 0 for current
+---@private
+local function clear(bufnr)
+  bufnr = resolve_bufnr(bufnr)
+  if not bufstates[bufnr] then
+    return
+  end
+  reset_timer(bufnr)
+  local bufstate = bufstates[bufnr]
+  local client_lens = (bufstate or {}).client_hint or {}
+  local client_ids = vim.tbl_keys(client_lens)
+  for _, iter_client_id in ipairs(client_ids) do
+    if bufstate then
+      bufstate.client_hint[iter_client_id] = {}
+    end
+  end
+  api.nvim_buf_clear_namespace(bufnr, namespace, 0, -1)
+  api.nvim__buf_redraw_range(bufnr, 0, -1)
+end
+
+---@private
+local function make_request(request_bufnr)
+  reset_timer(request_bufnr)
+  refresh({ bufnr = request_bufnr })
+end
+
+--- Enable inlay hints for a buffer
+---@param bufnr (integer) Buffer handle, or 0 for current
+---@private
+local function enable(bufnr)
+  bufnr = resolve_bufnr(bufnr)
+  local bufstate = bufstates[bufnr]
+  if not (bufstate and bufstate.enabled) then
+    bufstates[bufnr] = { enabled = true, timer = nil, applied = {} }
+    refresh({ bufnr = bufnr })
+    api.nvim_buf_attach(bufnr, true, {
+      on_lines = function(_, cb_bufnr)
+        if not bufstates[cb_bufnr].enabled then
+          return true
+        end
+        reset_timer(cb_bufnr)
+        bufstates[cb_bufnr].timer = vim.defer_fn(function()
+          make_request(cb_bufnr)
+        end, 200)
+      end,
+      on_reload = function(_, cb_bufnr)
+        clear(cb_bufnr)
+        if bufstates[cb_bufnr] and bufstates[cb_bufnr].enabled then
+          bufstates[cb_bufnr] = { enabled = true, applied = {} }
+        end
+        refresh({ bufnr = cb_bufnr })
+      end,
+      on_detach = function(_, cb_bufnr)
+        clear(cb_bufnr)
+        bufstates[cb_bufnr] = nil
+      end,
+    })
+    api.nvim_create_autocmd('LspDetach', {
+      buffer = bufnr,
+      callback = function(opts)
+        clear(opts.buf)
+      end,
+      once = true,
+      group = augroup,
+    })
+  end
+end
+
+--- Disable inlay hints for a buffer
+---@param bufnr (integer) Buffer handle, or 0 for current
+---@private
+local function disable(bufnr)
+  bufnr = resolve_bufnr(bufnr)
+  if bufstates[bufnr] and bufstates[bufnr].enabled then
+    clear(bufnr)
+    bufstates[bufnr].enabled = nil
+    bufstates[bufnr].timer = nil
+  end
+end
+
+--- Toggle inlay hints for a buffer
+---@param bufnr (integer) Buffer handle, or 0 for current
+---@private
+local function toggle(bufnr)
+  bufnr = resolve_bufnr(bufnr)
+  local bufstate = bufstates[bufnr]
+  if bufstate and bufstate.enabled then
+    M.disable(bufnr)
+  else
+    M.enable(bufnr)
+  end
+end
+
+api.nvim_set_decoration_provider(namespace, {
+  on_win = function(_, _, bufnr, topline, botline)
+    local bufstate = bufstates[bufnr]
+    if not bufstate then
+      return
+    end
+
+    if bufstate.version ~= util.buf_versions[bufnr] then
+      return
+    end
+    local hints_by_client = bufstate.client_hint
+
+    for lnum = topline, botline do
+      if bufstate.applied[lnum] ~= bufstate.version then
+        api.nvim_buf_clear_namespace(bufnr, namespace, lnum, lnum + 1)
+        for _, hints_by_lnum in pairs(hints_by_client) do
+          local line_hints = hints_by_lnum[lnum] or {}
+          for _, hint in pairs(line_hints) do
+            local text = ''
+            if type(hint.label) == 'string' then
+              text = hint.label
+            else
+              for _, part in ipairs(hint.label) do
+                text = text .. part.value
+              end
+            end
+            local vt = {}
+            if hint.paddingLeft then
+              vt[#vt + 1] = { ' ' }
+            end
+            vt[#vt + 1] = { text, 'LspInlayHint' }
+            if hint.paddingRight then
+              vt[#vt + 1] = { ' ' }
+            end
+            api.nvim_buf_set_extmark(bufnr, namespace, lnum, hint.position.character, {
+              virt_text_pos = 'inline',
+              ephemeral = false,
+              virt_text = vt,
+              hl_mode = 'combine',
+            })
+          end
+        end
+        bufstate.applied[lnum] = bufstate.version
+      end
+    end
+  end,
+})
+
+return setmetatable(M, {
+  __call = function(_, bufnr, enable_)
+    vim.validate({ enable = { enable_, { 'boolean', 'nil' } }, bufnr = { bufnr, 'number' } })
+    if enable_ then
+      enable(bufnr)
+    elseif enable_ == false then
+      disable(bufnr)
+    else
+      toggle(bufnr)
+    end
+  end,
+})