Rework standardizer to use --stdin instead of creating temp files (te…

…st is almost twice as fast)

Running lsp_test.rb after this commit: 0.075s - 0.085s
Running before this commit: 0.129s - 0.141s

lib/standard/lsp/routes.rb

@@ -130,13 +130,18 @@ def handle_method_missing(request)
 
       private
 
+      def uri_to_path(uri)
+        # TODO: make this real
+        uri.sub(%r{^file:///}, "")
+      end
+
       def format_file(file_uri)
         text = @text_cache[file_uri]
         if text.nil?
           @logger.puts "Format request arrived before text synchonized; skipping: `#{file_uri}'"
           []
         else
-          new_text = @standardizer.format(text)
+          new_text = @standardizer.format(uri_to_path(file_uri), text)
           if new_text == text
             []
           else
@@ -153,7 +158,7 @@ def format_file(file_uri)
 
       def diagnostic(file_uri, text)
         @text_cache[file_uri] = text
-        offenses = @standardizer.offenses(text)
+        offenses = @standardizer.offenses(uri_to_path(file_uri), text)
 
         lsp_diagnostics = offenses.map { |o|
           code = o[:cop_name]

lib/standard/lsp/standardizer.rb

@@ -1,49 +1,51 @@
 require_relative "../runners/rubocop"
-require "tempfile"
 
 module Standard
   module Lsp
     class Standardizer
       def initialize(config)
-        @template_options = config
-        @runner = Standard::Runners::Rubocop.new
+        @config = config
+        @rubocop_runner = Standard::Runners::Rubocop.new
       end
 
-      def format(text)
-        run_standard(text, format: true)
+      # This abuses the --stdin option of rubocop and reads the formatted text
+      # from the options[:stdin] that rubocop mutates. This depends on
+      # parallel: false as well as the fact that rubocop doesn't otherwise dup
+      # or reassign that options object. Risky business!
+      #
+      # Reassigning options[:stdin] is done here:
+      #   https://github.com/rubocop/rubocop/blob/master/lib/rubocop/cop/team.rb#L131
+      # Printing options[:stdin]
+      #   https://github.com/rubocop/rubocop/blob/master/lib/rubocop/cli/command/execute_runner.rb#L95
+      # Setting `parallel: true` would break this here:
+      #   https://github.com/rubocop/rubocop/blob/master/lib/rubocop/runner.rb#L72
+      def format(path, text)
+        ad_hoc_config = fork_config(path, text, format: true)
+        capture_rubocop_stdout(ad_hoc_config)
+        ad_hoc_config.rubocop_options[:stdin]
       end
 
-      def offenses(text)
-        results = run_standard(text, format: false)
+      def offenses(path, text)
+        results = capture_rubocop_stdout(fork_config(path, text, format: false))
         JSON.parse(results, symbolize_names: true).dig(:files, 0, :offenses)
       end
 
       private
 
-      BASENAME = ["source", ".rb"].freeze
-      def run_standard(text, format:)
-        Tempfile.open(BASENAME) do |temp|
-          temp.write(text)
-          temp.flush
-          stdout = capture_rubocop_stdout(make_config(temp.path, format))
-          format ? File.read(temp.path) : stdout
-        end
-      end
-
-      def make_config(file, format)
-        # Can't make frozen versions of this hash because RuboCop mutates it
+      # Can't make frozen versions of this hash because RuboCop mutates it
+      def fork_config(path, text, format:)
         o = if format
-          {autocorrect: true, formatters: [["Standard::Formatter", nil]], parallel: true, todo_file: nil, todo_ignore_files: [], safe_autocorrect: true}
+          {stdin: text, autocorrect: true, formatters: [["Standard::Formatter", nil]], parallel: false, todo_file: nil, todo_ignore_files: [], safe_autocorrect: true}
         else
-          {autocorrect: false, formatters: [["json"]], parallel: true, todo_file: nil, todo_ignore_files: [], format: "json"}
+          {stdin: text, autocorrect: false, formatters: [["json"]], parallel: false, todo_file: nil, todo_ignore_files: [], format: "json"}
         end
-        Standard::Config.new(@template_options.runner, [file], o, @template_options.rubocop_config_store)
+        Standard::Config.new(@config.runner, [path], o, @config.rubocop_config_store)
       end
 
       def capture_rubocop_stdout(config)
         redir = StringIO.new
         $stdout = redir
-        @runner.call(config)
+        @rubocop_runner.call(config)
         redir.string
       ensure
         $stdout = STDOUT

test/standard/runners/lsp_test.rb

@@ -117,7 +117,7 @@ def test_format
         params: {
           textDocument: {
             languageId: "ruby",
-            text: "def hi\n  [1, 2,\n   3  ]\nend\n",
+            text: "puts 'hi'",
             uri: "file:///path/to/file.rb",
             version: 0
           }
@@ -127,7 +127,7 @@ def test_format
         method: "textDocument/didChange",
         jsonrpc: "2.0",
         params: {
-          contentChanges: [{text: "def goodbye\n  [3, 2,\n   1  ]\n\nend\n"}],
+          contentChanges: [{text: "puts 'bye'"}],
           textDocument: {
             uri: "file:///path/to/file.rb",
             version: 10
@@ -151,10 +151,10 @@ def test_format
       {
         id: 20,
         result: [
-          {newText: "def goodbye\n  [3, 2,\n    1]\nend\n",
+          {newText: "puts \"bye\"\n",
            range: {
              start: {line: 0, character: 0},
-             end: {line: 6, character: 0}
+             end: {line: 1, character: 0}
            }}
         ],
         jsonrpc: "2.0"