1 files changed, 107 insertions, 0 deletions
diff --git a/.config/nvim/lsp/clangd.lua b/.config/nvim/lsp/clangd.lua
new file mode 100644
index 0000000..01ae2e1
--- /dev/null
+++ b/.config/nvim/lsp/clangd.lua
@@ -0,0 +1,107 @@
+-- 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)
+    local method_name = 'textDocument/switchSourceHeader'
+    local client = vim.lsp.get_clients({ bufnr = bufnr, name = 'clangd' })[1]
+    if not client 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)
+    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()
+    local bufnr = vim.api.nvim_get_current_buf()
+    local clangd_client = vim.lsp.get_clients({ bufnr = bufnr, name = 'clangd' })[1]
+    if not clangd_client or not clangd_client.supports_method('textDocument/symbolInfo') 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, clangd_client.offset_encoding)
+    clangd_client.request('textDocument/symbolInfo', params, function(err, res)
+        if err or #res == 0 then
+            -- Clangd always returns an error, there is not 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,
+            border = 'single',
+            title = 'Symbol Info',
+        })
+    end, bufnr)
+end
+
+return {
+    mason = false,
+    cmd = {
+        'clangd',
+        '--background-index',
+        '--clang-tidy',
+        '--header-insertion=iwyu',
+        '--completion-style=detailed',
+        '--function-arg-placeholders',
+        '--fallback-style=llvm',
+    },
+    filetypes = { 'c', 'cpp', 'objc', 'objcpp', 'cuda', 'proto' },
+    root_markers = {
+        '.clangd',
+        '.clang-tidy',
+        '.clang-format',
+        'compile_commands.json',
+        'compile_flags.txt',
+        'configure.ac', -- AutoTools
+        '.git',
+    },
+    init_options = {
+        usePlaceholders = true,
+        completeUnimported = true,
+        clangdFileStatus = true,
+    },
+    capabilities = {
+        textDocument = {
+            completion = {
+                editsNearCursor = true,
+            },
+        },
+        offsetEncoding = { 'utf-8', 'utf-16' },
+    },
+    on_attach = function()
+        vim.api.nvim_buf_create_user_command(0, 'ClangdSwitchSourceHeader', function()
+            switch_source_header(0)
+        end, { desc = 'Switch between source/header' })
+
+        vim.api.nvim_buf_create_user_command(0, 'ClangdShowSymbolInfo', function()
+            symbol_info()
+        end, { desc = 'Show symbol info' })
+
+        vim.keymap.set('n', 'H', '<cmd>ClangdSwitchSourceHeader<cr>', { desc = '[H]eader and Source Switcher' })
+        vim.keymap.set('n', 'K', '<cmd>lua require("pretty_hover").hover()<cr>', { desc = 'Documentation Hover' })
+        -- TODO: do I need pretty_hover? maybe that's what causes issues?
+    end,
+}