1 files changed, 103 insertions, 0 deletions
diff --git a/.config/nvim/lsp/clangd.lua b/.config/nvim/lsp/clangd.lua
new file mode 100644
index 0000000..c06cefa
--- /dev/null
+++ b/.config/nvim/lsp/clangd.lua
@@ -0,0 +1,103 @@
+---@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",
+		"--fallback-style=gnu"
+	},
+	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,
+}