1 files changed, 121 insertions, 0 deletions
diff --git a/.config/nvim/lsp/rust_analyzer.lua b/.config/nvim/lsp/rust_analyzer.lua
new file mode 100644
index 0000000..a699c7f
--- /dev/null
+++ b/.config/nvim/lsp/rust_analyzer.lua
@@ -0,0 +1,121 @@
+---@brief
+---
+--- https://github.com/rust-lang/rust-analyzer
+---
+--- rust-analyzer (aka rls 2.0), a language server for Rust
+---
+---
+--- See [docs](https://rust-analyzer.github.io/book/configuration.html) for extra settings. The settings can be used like this:
+--- ```lua
+--- vim.lsp.config('rust_analyzer', {
+---   settings = {
+---     ['rust-analyzer'] = {
+---       diagnostics = {
+---         enable = false;
+---       }
+---     }
+---   }
+--- })
+--- ```
+---
+--- Note: do not set `init_options` for this LS config, it will be automatically populated by the contents of settings["rust-analyzer"] per
+--- https://github.com/rust-lang/rust-analyzer/blob/eb5da56d839ae0a9e9f50774fa3eb78eb0964550/docs/dev/lsp-extensions.md?plain=1#L26.
+
+local function reload_workspace(bufnr)
+  local clients = vim.lsp.get_clients { bufnr = bufnr, name = 'rust_analyzer' }
+  for _, client in ipairs(clients) do
+    vim.notify 'Reloading Cargo Workspace'
+    ---@diagnostic disable-next-line:param-type-mismatch
+    client:request('rust-analyzer/reloadWorkspace', nil, function(err)
+      if err then
+        error(tostring(err))
+      end
+      vim.notify 'Cargo workspace reloaded'
+    end, 0)
+  end
+end
+
+local function is_library(fname)
+  local user_home = vim.fs.normalize(vim.env.HOME)
+  local cargo_home = os.getenv 'CARGO_HOME' or user_home .. '/.cargo'
+  local registry = cargo_home .. '/registry/src'
+  local git_registry = cargo_home .. '/git/checkouts'
+
+  local rustup_home = os.getenv 'RUSTUP_HOME' or user_home .. '/.rustup'
+  local toolchains = rustup_home .. '/toolchains'
+
+  for _, item in ipairs { toolchains, registry, git_registry } do
+    if vim.fs.relpath(item, fname) then
+      local clients = vim.lsp.get_clients { name = 'rust_analyzer' }
+      return #clients > 0 and clients[#clients].config.root_dir or nil
+    end
+  end
+end
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'rust-analyzer' },
+  filetypes = { 'rust' },
+  root_dir = function(bufnr, on_dir)
+    local fname = vim.api.nvim_buf_get_name(bufnr)
+    local reused_dir = is_library(fname)
+    if reused_dir then
+      on_dir(reused_dir)
+      return
+    end
+
+    local cargo_crate_dir = vim.fs.root(fname, { 'Cargo.toml' })
+    local cargo_workspace_root
+
+    if cargo_crate_dir == nil then
+      on_dir(
+        vim.fs.root(fname, { 'rust-project.json' })
+          or vim.fs.dirname(vim.fs.find('.git', { path = fname, upward = true })[1])
+      )
+      return
+    end
+
+    local cmd = {
+      'cargo',
+      'metadata',
+      '--no-deps',
+      '--format-version',
+      '1',
+      '--manifest-path',
+      cargo_crate_dir .. '/Cargo.toml',
+    }
+
+    vim.system(cmd, { text = true }, function(output)
+      if output.code == 0 then
+        if output.stdout then
+          local result = vim.json.decode(output.stdout)
+          if result['workspace_root'] then
+            cargo_workspace_root = vim.fs.normalize(result['workspace_root'])
+          end
+        end
+
+        on_dir(cargo_workspace_root or cargo_crate_dir)
+      else
+        vim.schedule(function()
+          vim.notify(('[rust_analyzer] cmd failed with code %d: %s\n%s'):format(output.code, cmd, output.stderr))
+        end)
+      end
+    end)
+  end,
+  capabilities = {
+    experimental = {
+      serverStatusNotification = true,
+    },
+  },
+  before_init = function(init_params, config)
+    -- See https://github.com/rust-lang/rust-analyzer/blob/eb5da56d839ae0a9e9f50774fa3eb78eb0964550/docs/dev/lsp-extensions.md?plain=1#L26
+    if config.settings and config.settings['rust-analyzer'] then
+      init_params.initializationOptions = config.settings['rust-analyzer']
+    end
+  end,
+  on_attach = function(_, bufnr)
+    vim.api.nvim_buf_create_user_command(bufnr, 'LspCargoReload', function()
+      reload_workspace(bufnr)
+    end, { desc = 'Reload current cargo workspace' })
+  end,
+}