feat(lsp): target architecture switching command for RustAnalyzer

doc/rustaceanvim.txt

@@ -24,6 +24,9 @@ Commands:
  ':RustAnalyzer stop' - Stop the LSP client.
  ':RustAnalyzer restart' - Restart the LSP client.
  ':RustAnalyzer reloadSettings' - Reload settings for the LSP client.
+ ':RustAnalyzer target <target_arch>' - Set the target architecture for the LSP client.
+
+The ':RustAnalyzer target' command can take a valid rustc target, such as 'wasm32-unknown-unknown', or it can be left empty to set the LSP client to use the default target architecture for the operating system.
 
 The ':RustLsp[!]' command is available after the LSP client has initialized.
 It accepts the following subcommands:

lua/rustaceanvim/init.lua

@@ -16,6 +16,11 @@
 --- ':RustAnalyzer stop' - Stop the LSP client.
 --- ':RustAnalyzer restart' - Restart the LSP client.
 --- ':RustAnalyzer reloadSettings' - Reload settings for the LSP client.
+--- ':RustAnalyzer target <target_arch>' - Set the target architecture for the LSP client.
+
+--- The ':RustAnalyzer target' command can take a valid rustc target,
+--- such as 'wasm32-unknown-unknown', or it can be left empty to set the LSP client
+--- to use the default target architecture for the operating system.
 ---
 ---The ':RustLsp[!]' command is available after the LSP client has initialized.
 ---It accepts the following subcommands:

lua/rustaceanvim/lsp/init.lua

@@ -6,6 +6,7 @@ local rust_analyzer = require('rustaceanvim.rust_analyzer')
 local server_status = require('rustaceanvim.server_status')
 local cargo = require('rustaceanvim.cargo')
 local os = require('rustaceanvim.os')
+local targets = require('rustaceanvim.lsp.targets')
 
 local function override_apply_text_edits()
   local old_func = vim.lsp.util.apply_text_edits
@@ -93,6 +94,45 @@ local function configure_file_watcher(server_cfg)
   end
 end
 
+---LSP restart ininer implementations
+---@param bufnr? number
+---@param set_target_callback? function(client) Optional callback to run for each client before restarting.
+---@return number|nil client_id
+local function restart(bufnr, set_target_callback)
+  bufnr = bufnr or vim.api.nvim_get_current_buf()
+  local clients = M.stop(bufnr)
+  local timer, _, _ = vim.uv.new_timer()
+  if not timer then
+    vim.notify('Failed to init timer for LSP client restart.', vim.log.levels.ERROR)
+    return
+  end
+  local attempts_to_live = 50
+  local stopped_client_count = 0
+  timer:start(200, 100, function()
+    for _, client in ipairs(clients) do
+      if client:is_stopped() then
+        stopped_client_count = stopped_client_count + 1
+        vim.schedule(function()
+          -- Execute the callback, if provided, for additional actions before restarting
+          if set_target_callback then
+            set_target_callback(client)
+          end
+          M.start(bufnr)
+        end)
+      end
+    end
+    if stopped_client_count >= #clients then
+      timer:stop()
+      attempts_to_live = 0
+    elseif attempts_to_live <= 0 then
+      vim.notify('rustaceanvim.lsp: Could not restart all LSP clients.', vim.log.levels.ERROR)
+      timer:stop()
+      attempts_to_live = 0
+    end
+    attempts_to_live = attempts_to_live - 1
+  end)
+end
+
 ---@class rustaceanvim.lsp.StartConfig: rustaceanvim.lsp.ClientConfig
 ---@field root_dir string | nil
 ---@field init_options? table
@@ -249,39 +289,43 @@ M.reload_settings = function(bufnr)
   return clients
 end
 
+---Updates the target architecture setting for the LSP client associated with the given buffer.
+---@param bufnr? number The buffer number, defaults to the current buffer
+---@param target? string The target architecture. Defaults to the current buffer's target if not provided.
+M.set_target_arch = function(bufnr, target)
+  local function update_target(client)
+    -- Get the current target from the client's settings
+    local current_target = vim.tbl_get(client, 'config', 'settings', 'rust-analyzer', 'cargo', 'target')
+
+    if not target then
+      if not current_target then
+        vim.notify('Using default OS target architecture.', vim.log.levels.INFO)
+      else
+        vim.notify('Target architecture is already set to the default OS target.', vim.log.levels.INFO)
+      end
+      return
+    end
+
+    if targets.target_is_valid_rustc_target(target) then
+      client.settings['rust-analyzer'].cargo.target = target
+      client.notify('workspace/didChangeConfiguration', { settings = client.config.settings })
+      vim.notify('Target architecture updated successfully to: ' .. target, vim.log.levels.INFO)
+      return
+    else
+      vim.notify('Invalid target architecture provided: ' .. tostring(target), vim.log.levels.ERROR)
+      return
+    end
+  end
+
+  restart(bufnr, update_target)
+end
+
 ---Restart the LSP client.
 ---Fails silently if the buffer's filetype is not one of the filetypes specified in the config.
 ---@param bufnr? number The buffer number (optional), defaults to the current buffer
 ---@return number|nil client_id The LSP client ID after restart
 M.restart = function(bufnr)
-  bufnr = bufnr or vim.api.nvim_get_current_buf()
-  local clients = M.stop(bufnr)
-  local timer, _, _ = vim.uv.new_timer()
-  if not timer then
-    -- TODO: Log error when logging is implemented
-    return
-  end
-  local attempts_to_live = 50
-  local stopped_client_count = 0
-  timer:start(200, 100, function()
-    for _, client in ipairs(clients) do
-      if client:is_stopped() then
-        stopped_client_count = stopped_client_count + 1
-        vim.schedule(function()
-          M.start(bufnr)
-        end)
-      end
-    end
-    if stopped_client_count >= #clients then
-      timer:stop()
-      attempts_to_live = 0
-    elseif attempts_to_live <= 0 then
-      vim.notify('rustaceanvim.lsp: Could not restart all LSP clients.', vim.log.levels.ERROR)
-      timer:stop()
-      attempts_to_live = 0
-    end
-    attempts_to_live = attempts_to_live - 1
-  end)
+  M.restart(bufnr)
 end
 
 ---@enum RustAnalyzerCmd
@@ -290,11 +334,13 @@ local RustAnalyzerCmd = {
   stop = 'stop',
   restart = 'restart',
   reload_settings = 'reloadSettings',
+  target = 'target',
 }
 
 local function rust_analyzer_cmd(opts)
   local fargs = opts.fargs
   local cmd = fargs[1]
+  local arch = fargs[2]
   ---@cast cmd RustAnalyzerCmd
   if cmd == RustAnalyzerCmd.start then
     M.start()
@@ -304,12 +350,14 @@ local function rust_analyzer_cmd(opts)
     M.restart()
   elseif cmd == RustAnalyzerCmd.reload_settings then
     M.reload_settings()
+  elseif cmd == RustAnalyzerCmd.target then
+    M.set_target_arch(nil, arch)
   end
 end
 
 vim.api.nvim_create_user_command('RustAnalyzer', rust_analyzer_cmd, {
   nargs = '+',
-  desc = 'Starts or stops the rust-analyzer LSP client',
+  desc = 'Starts, stops the rust-analyzer LSP client or changes the target',
   complete = function(arg_lead, cmdline, _)
     local clients = rust_analyzer.get_active_rustaceanvim_clients()
     ---@type RustAnalyzerCmd[]

lua/rustaceanvim/lsp/targets.lua

@@ -0,0 +1,43 @@
+local T = {}
+
+local rustc_targets_cache = nil
+
+--- Get rustc targets, use cache if available
+---@return table<string, boolean>
+local function get_rustc_targets()
+  if rustc_targets_cache then
+    return rustc_targets_cache
+  end
+
+  local result = vim.system({ 'rustc', '--print', 'target-list' }):wait()
+  if result.code ~= 0 then
+    error('Failed to retrieve rustc targets: ' .. result.stderr)
+  end
+
+  rustc_targets_cache = {}
+  for line in result.stdout:gmatch('[^\r\n]+') do
+    rustc_targets_cache[line] = true
+  end
+
+  return rustc_targets_cache
+end
+
+--- Validates if the provided target is a valid Rust compiler (rustc) target.
+--- If no target is provided, it defaults to the system's architecture.
+---@param target? string
+---@return boolean
+function T.target_is_valid_rustc_target(target)
+  if target == nil then
+    return true
+  end
+
+  local success, targets = pcall(get_rustc_targets)
+  if not success then
+    vim.notify('Error retrieving rustc targets: ' .. tostring(targets), vim.log.levels.ERROR)
+    return false
+  end
+
+  return targets[target] or false
+end
+
+return T