1 files changed, 100 insertions, 0 deletions
diff --git a/.config/nvim/lsp/clangd.lua b/.config/nvim/lsp/clangd.lua
new file mode 100644
index 0000000..07ad347
--- /dev/null
+++ b/.config/nvim/lsp/clangd.lua
@@ -0,0 +1,100 @@
+---@brief
+---
+--- https://clangd.llvm.org/installation.html
+---
+--- - **NOTE:** Clang >= 11 is recommended! See [#23](https://github.com/neovim/nvim-lspconfig/issues/23).
+--- - If `compile_commands.json` lives in a build directory, you should
+---   symlink it to the root of your source tree.
+---   ```
+---   ln -s /path/to/myproject/build/compile_commands.json /path/to/myproject/
+---   ```
+--- - clangd relies on a [JSON compilation database](https://clang.llvm.org/docs/JSONCompilationDatabase.html)
+---   specified as compile_commands.json, see https://clangd.llvm.org/installation#compile_commandsjson
+
+-- https://clangd.llvm.org/extensions.html#switch-between-sourceheader
+local function switch_source_header(bufnr, client)
+  local method_name = 'textDocument/switchSourceHeader'
+  ---@diagnostic disable-next-line:param-type-mismatch
+  if not client or not client:supports_method(method_name) then
+    return vim.notify(('method %s is not supported by any servers active on the current buffer'):format(method_name))
+  end
+  local params = vim.lsp.util.make_text_document_params(bufnr)
+  ---@diagnostic disable-next-line:param-type-mismatch
+  client:request(method_name, params, function(err, result)
+    if err then
+      error(tostring(err))
+    end
+    if not result then
+      vim.notify('corresponding file cannot be determined')
+      return
+    end
+    vim.cmd.edit(vim.uri_to_fname(result))
+  end, bufnr)
+end
+
+local function symbol_info(bufnr, client)
+  local method_name = 'textDocument/symbolInfo'
+  ---@diagnostic disable-next-line:param-type-mismatch
+  if not client or not client:supports_method(method_name) then
+    return vim.notify('Clangd client not found', vim.log.levels.ERROR)
+  end
+  local win = vim.api.nvim_get_current_win()
+  local params = vim.lsp.util.make_position_params(win, client.offset_encoding)
+  ---@diagnostic disable-next-line:param-type-mismatch
+  client:request(method_name, params, function(err, res)
+    if err or #res == 0 then
+      -- Clangd always returns an error, there is no reason to parse it
+      return
+    end
+    local container = string.format('container: %s', res[1].containerName) ---@type string
+    local name = string.format('name: %s', res[1].name) ---@type string
+    vim.lsp.util.open_floating_preview({ name, container }, '', {
+      height = 2,
+      width = math.max(string.len(name), string.len(container)),
+      focusable = false,
+      focus = false,
+      title = 'Symbol Info',
+    })
+  end, bufnr)
+end
+
+---@class ClangdInitializeResult: lsp.InitializeResult
+---@field offsetEncoding? string
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'clangd' },
+  filetypes = { 'c', 'cpp', 'objc', 'objcpp', 'cuda' },
+  root_markers = {
+    '.clangd',
+    '.clang-tidy',
+    '.clang-format',
+    'compile_commands.json',
+    'compile_flags.txt',
+    'configure.ac', -- AutoTools
+    '.git',
+  },
+  capabilities = {
+    textDocument = {
+      completion = {
+        editsNearCursor = true,
+      },
+    },
+    offsetEncoding = { 'utf-8', 'utf-16' },
+  },
+  ---@param init_result ClangdInitializeResult
+  on_init = function(client, init_result)
+    if init_result.offsetEncoding then
+      client.offset_encoding = init_result.offsetEncoding
+    end
+  end,
+  on_attach = function(client, bufnr)
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspClangdSwitchSourceHeader', function()
+      switch_source_header(bufnr, client)
+    end, { desc = 'Switch between source/header' })
+
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspClangdShowSymbolInfo', function()
+      symbol_info(bufnr, client)
+    end, { desc = 'Show symbol info' })
+  end,
+}