Initial commit of 001code-html Scratch frontend project.

Includes scratch-gui, scratch-vm, scratch-blocks, scratch-render, scratch-l10n, and deployment config.

Co-authored-by: Cursor <cursoragent@cursor.com>

scratch-blocks/build.py

@@ -0,0 +1,647 @@
+#!/usr/bin/python2.7
+# Compresses the core Blockly files into a single JavaScript file.
+#
+# Copyright 2012 Google Inc.
+# https://developers.google.com/blockly/
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script generates two versions of Blockly's core files:
+#   blockly_compressed.js
+#   blockly_uncompressed.js
+# The compressed file is a concatenation of all of Blockly's core files which
+# have been run through Google's Closure Compiler.  This is done using the
+# online API (which takes a few seconds and requires an Internet connection).
+# The uncompressed file is a script that loads in each of Blockly's core files
+# one by one.  This takes much longer for a browser to load, but is useful
+# when debugging code since line numbers are meaningful and variables haven't
+# been renamed.  The uncompressed file also allows for a faster developement
+# cycle since there is no need to rebuild or recompile, just reload.
+#
+# This script also generates:
+#   blocks_compressed.js: The compressed common blocks.
+#   blocks_horizontal_compressed.js: The compressed Scratch horizontal blocks.
+#   blocks_vertical_compressed.js: The compressed Scratch vertical blocks.
+#   msg/js/<LANG>.js for every language <LANG> defined in msg/js/<LANG>.json.
+
+import sys
+
+import errno, glob, json, os, re, subprocess, threading, codecs, functools, platform
+
+if sys.version_info[0] == 2:
+  import httplib
+  from urllib import urlencode
+else:
+  import http.client as httplib
+  from urllib.parse import urlencode
+  from importlib import reload
+
+REMOTE_COMPILER = "remote"
+
+CLOSURE_DIR = os.path.pardir
+CLOSURE_ROOT = os.path.pardir
+CLOSURE_LIBRARY = "closure-library"
+CLOSURE_COMPILER = REMOTE_COMPILER
+
+CLOSURE_DIR_NPM = "node_modules"
+CLOSURE_ROOT_NPM = os.path.join("node_modules")
+CLOSURE_LIBRARY_NPM = "google-closure-library"
+CLOSURE_COMPILER_NPM = ("google-closure-compiler.cmd" if os.name == "nt" else "google-closure-compiler")
+
+def import_path(fullpath):
+  """Import a file with full path specification.
+  Allows one to import from any directory, something __import__ does not do.
+
+  Args:
+      fullpath:  Path and filename of import.
+
+  Returns:
+      An imported module.
+  """
+  path, filename = os.path.split(fullpath)
+  filename, ext = os.path.splitext(filename)
+  sys.path.append(path)
+  module = __import__(filename)
+  reload(module)  # Might be out of date.
+  del sys.path[-1]
+  return module
+
+def read(filename):
+    f = open(filename)
+    content = "".join(f.readlines())
+    f.close()
+    return content
+
+HEADER = ("// Do not edit this file; automatically generated by build.py.\n"
+          "'use strict';\n")
+
+
+class Gen_uncompressed(threading.Thread):
+  """Generate a JavaScript file that loads Blockly's raw files.
+  Runs in a separate thread.
+  """
+  def __init__(self, search_paths, vertical, closure_env):
+    threading.Thread.__init__(self)
+    self.search_paths = search_paths
+    self.vertical = vertical
+    self.closure_env = closure_env
+
+  def run(self):
+    if self.vertical:
+      target_filename = 'blockly_uncompressed_vertical.js'
+    else:
+      target_filename = 'blockly_uncompressed_horizontal.js'
+    f = open(target_filename, 'w')
+    f.write(HEADER)
+    f.write(self.format_js("""
+var isNodeJS = !!(typeof module !== 'undefined' && module.exports &&
+                  typeof window === 'undefined');
+
+if (isNodeJS) {
+  var window = {};
+  require('{closure_library}');
+}
+
+window.BLOCKLY_DIR = (function() {
+  if (!isNodeJS) {
+    // Find name of current directory.
+    var scripts = document.getElementsByTagName('script');
+    var re = new RegExp('(.+)[\\/]blockly_uncompressed(_vertical|_horizontal|)\\.js$');
+    for (var i = 0, script; script = scripts[i]; i++) {
+      var match = re.exec(script.src);
+      if (match) {
+        return match[1];
+      }
+    }
+    alert('Could not detect Blockly\\'s directory name.');
+  }
+  return '';
+})();
+
+window.BLOCKLY_BOOT = function() {
+  var dir = '';
+  if (isNodeJS) {
+    require('{closure_library}');
+    dir = 'blockly';
+  } else {
+    // Execute after Closure has loaded.
+    if (!window.goog) {
+      alert('Error: Closure not found.  Read this:\\n' +
+            'developers.google.com/blockly/guides/modify/web/closure');
+    }
+    if (window.BLOCKLY_DIR.search(/node_modules/)) {
+      dir = '..';
+    } else {
+      dir = window.BLOCKLY_DIR.match(/[^\\/]+$/)[0];
+    }
+  }
+"""))
+    add_dependency = []
+    base_path = calcdeps.FindClosureBasePath(self.search_paths)
+    for dep in calcdeps.BuildDependenciesFromFiles(self.search_paths):
+      add_dependency.append(calcdeps.GetDepsLine(dep, base_path))
+    add_dependency.sort()  # Deterministic build.
+    add_dependency = '\n'.join(add_dependency)
+    # Find the Blockly directory name and replace it with a JS variable.
+    # This allows blockly_uncompressed.js to be compiled on one computer and be
+    # used on another, even if the directory name differs.
+    m = re.search('[\\/]([^\\/]+)[\\/]core[\\/]blockly.js', add_dependency)
+    add_dependency = re.sub('([\\/])' + re.escape(m.group(1)) +
+        '([\\/]core[\\/])', '\\1" + dir + "\\2', add_dependency)
+    f.write(add_dependency + '\n')
+
+    provides = []
+    for dep in calcdeps.BuildDependenciesFromFiles(self.search_paths):
+      # starts with '../' or 'node_modules/'
+      if not dep.filename.startswith(self.closure_env["closure_root"] + os.sep):
+        provides.extend(dep.provides)
+    provides.sort()  # Deterministic build.
+    f.write('\n')
+    f.write('// Load Blockly.\n')
+    for provide in provides:
+      f.write("goog.require('%s');\n" % provide)
+
+    f.write(self.format_js("""
+delete this.BLOCKLY_DIR;
+delete this.BLOCKLY_BOOT;
+};
+
+if (isNodeJS) {
+  window.BLOCKLY_BOOT();
+  module.exports = Blockly;
+} else {
+  // Delete any existing Closure (e.g. Soy's nogoog_shim).
+  document.write('<script>var goog = undefined;</script>');
+  // Load fresh Closure Library.
+  document.write('<script src="' + window.BLOCKLY_DIR +
+      '/{closure_dir}/{closure_library}/closure/goog/base.js"></script>');
+  document.write('<script>window.BLOCKLY_BOOT();</script>');
+}
+"""))
+    f.close()
+    print("SUCCESS: " + target_filename)
+
+  def format_js(self, code):
+    """Format JS in a way that python's format method can work with to not
+    consider brace-wrapped sections to be format replacements while still
+    replacing known keys.
+    """
+
+    key_whitelist = self.closure_env.keys()
+
+    keys_pipe_separated = functools.reduce(lambda accum, key: accum + "|" + key, key_whitelist)
+    begin_brace = re.compile(r"\{(?!%s)" % (keys_pipe_separated,))
+
+    end_brace = re.compile(r"\}")
+    def end_replacement(match):
+      try:
+        maybe_key = match.string[match.string[:match.start()].rindex("{") + 1:match.start()]
+      except ValueError:
+        return "}}"
+
+      if maybe_key and maybe_key in key_whitelist:
+        return "}"
+      else:
+        return "}}"
+
+    return begin_brace.sub("{{", end_brace.sub(end_replacement, code)).format(**self.closure_env)
+
+class Gen_compressed(threading.Thread):
+  """Generate a JavaScript file that contains all of Blockly's core and all
+  required parts of Closure, compiled together.
+  Uses the Closure Compiler's online API.
+  Runs in a separate thread.
+  """
+  def __init__(self, search_paths_vertical, search_paths_horizontal, closure_env):
+    threading.Thread.__init__(self)
+    self.search_paths_vertical = search_paths_vertical
+    self.search_paths_horizontal = search_paths_horizontal
+    self.closure_env = closure_env
+
+  def run(self):
+    self.gen_core(True)
+    self.gen_core(False)
+    self.gen_blocks("horizontal")
+    self.gen_blocks("vertical")
+    self.gen_blocks("common")
+
+  def gen_core(self, vertical):
+    if vertical:
+      target_filename = 'blockly_compressed_vertical.js'
+      search_paths = self.search_paths_vertical
+    else:
+      target_filename = 'blockly_compressed_horizontal.js'
+      search_paths = self.search_paths_horizontal
+    # Define the parameters for the POST request.
+    params = [
+      ("compilation_level", "SIMPLE"),
+
+      # remote will filter this out
+      ("language_in", "ECMASCRIPT_2017"),
+      ("language_out", "ECMASCRIPT5"),
+      ("rewrite_polyfills", "false"),
+      ("define", "goog.DEBUG=false"),
+
+      # local will filter this out
+      ("use_closure_library", "true"),
+    ]
+
+    # Read in all the source files.
+    filenames = calcdeps.CalculateDependencies(search_paths,
+      [os.path.join("core", "blockly.js")])
+    filenames.sort()  # Deterministic build.
+    for filename in filenames:
+      # Append filenames as false arguments the step before compiling will
+      # either transform them into arguments for local or remote compilation
+      params.append(("js_file", filename))
+
+    self.do_compile(params, target_filename, filenames, "")
+
+  def gen_blocks(self, block_type):
+    if block_type == "horizontal":
+      target_filename = "blocks_compressed_horizontal.js"
+      filenames = glob.glob(os.path.join("blocks_horizontal", "*.js"))
+    elif block_type == "vertical":
+      target_filename = "blocks_compressed_vertical.js"
+      filenames = glob.glob(os.path.join("blocks_vertical", "*.js"))
+    elif block_type == "common":
+      target_filename = "blocks_compressed.js"
+      filenames = glob.glob(os.path.join("blocks_common", "*.js"))
+
+    # glob.glob ordering is platform-dependent and not necessary deterministic
+    filenames.sort()  # Deterministic build.
+
+    # Define the parameters for the POST request.
+    params = [
+      ("compilation_level", "SIMPLE"),
+    ]
+
+    # Read in all the source files.
+    # Add Blockly.Blocks to be compatible with the compiler.
+    params.append(("js_file", os.path.join("build", "gen_blocks.js")))
+    # Add Blockly.Colours for use of centralized colour bank
+    filenames.append(os.path.join("core", "colours.js"))
+    filenames.append(os.path.join("core", "constants.js"))
+
+    for filename in filenames:
+      # Append filenames as false arguments the step before compiling will
+      # either transform them into arguments for local or remote compilation
+      params.append(("js_file", filename))
+
+    # Remove Blockly.Blocks to be compatible with Blockly.
+    remove = "var Blockly={Blocks:{}};"
+    self.do_compile(params, target_filename, filenames, remove)
+
+  def do_compile(self, params, target_filename, filenames, remove):
+    if self.closure_env["closure_compiler"] == REMOTE_COMPILER:
+      do_compile = self.do_compile_remote
+    else:
+      do_compile = self.do_compile_local
+    json_data = do_compile(params, target_filename)
+
+    if self.report_errors(target_filename, filenames, json_data):
+      self.write_output(target_filename, remove, json_data)
+      self.report_stats(target_filename, json_data)
+
+  def do_compile_local(self, params, target_filename):
+      filter_keys = ["use_closure_library"]
+
+      # Drop arg if arg is js_file else add dashes
+      dash_params = []
+      for (arg, value) in params:
+        dash_params.append((value,) if arg == "js_file" else ("--" + arg, value))
+
+      # Flatten dash_params into dash_args if their keys are not in filter_keys
+      dash_args = []
+      for pair in dash_params:
+        if pair[0][2:] not in filter_keys:
+          dash_args.extend(pair)
+
+      # Build the final args array by prepending CLOSURE_COMPILER_NPM to
+      # dash_args and dropping any falsy members
+      args = []
+      for group in [[CLOSURE_COMPILER_NPM], dash_args]:
+        args.extend(filter(lambda item: item, group))
+
+      # On Windows, the command line is too long, so we save the arguments to a file instead
+      use_flagfile = platform.system() == "Windows"
+      if platform.system() == "Windows":
+        flagfile_name = target_filename + ".config"
+        with open(flagfile_name, "w") as f:
+          # \ needs to be escaped still
+          f.write(" ".join(args[1:]).replace("\\", "\\\\"))
+        args = [CLOSURE_COMPILER_NPM, "--flagfile", flagfile_name]
+
+      proc = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+      (stdout, stderr) = proc.communicate()
+
+      if use_flagfile:
+        os.remove(flagfile_name)
+
+      # Build the JSON response.
+      filesizes = [os.path.getsize(value) for (arg, value) in params if arg == "js_file"]
+      return dict(
+        compiledCode=stdout,
+        statistics=dict(
+          originalSize=functools.reduce(lambda v, size: v + size, filesizes, 0),
+          compressedSize=len(stdout),
+        )
+      )
+
+  def do_compile_remote(self, params, target_filename):
+      filter_keys = [
+        "language_in",
+        "language_out",
+        "rewrite_polyfills",
+        "define",
+      ]
+
+      params.extend([
+        ("output_format", "json"),
+        ("output_info", "compiled_code"),
+        ("output_info", "warnings"),
+        ("output_info", "errors"),
+        ("output_info", "statistics"),
+      ])
+
+      # Send the request to Google.
+      remoteParams = []
+      for (arg, value) in params:
+        if not arg in filter_keys:
+          if arg == "js_file":
+            if not value.startswith(self.closure_env["closure_root"] + os.sep):
+              remoteParams.append(("js_code", read(value)))
+          # Change the normal compilation_level value SIMPLE to the remove
+          # service's SIMPLE_OPTIMIZATIONS
+          elif arg == "compilation_level" and value == "SIMPLE":
+            remoteParams.append((arg, "SIMPLE_OPTIMIZATIONS"))
+          else:
+            remoteParams.append((arg, value))
+
+      headers = {"Content-type": "application/x-www-form-urlencoded"}
+      conn = httplib.HTTPSConnection("closure-compiler.appspot.com")
+      conn.request("POST", "/compile", urlencode(remoteParams), headers)
+      response = conn.getresponse()
+      # Decode is necessary for Python 3.4 compatibility
+      json_str = response.read().decode("utf-8")
+      conn.close()
+
+      # Parse the JSON response.
+      return json.loads(json_str)
+
+  def report_errors(self, target_filename, filenames, json_data):
+    def file_lookup(name):
+      if not name.startswith("Input_"):
+        return "???"
+      n = int(name[6:]) - 1
+      return filenames[n]
+
+    if "serverErrors" in json_data:
+      errors = json_data["serverErrors"]
+      for error in errors:
+        print("SERVER ERROR: %s" % target_filename)
+        print(error["error"])
+    elif "errors" in json_data:
+      errors = json_data["errors"]
+      for error in errors:
+        print("FATAL ERROR")
+        print(error["error"])
+        if error["file"]:
+          print("%s at line %d:" % (
+              file_lookup(error["file"]), error["lineno"]))
+          print(error["line"])
+          print((" " * error["charno"]) + "^")
+        sys.exit(1)
+    else:
+      if "warnings" in json_data:
+        warnings = json_data["warnings"]
+        for warning in warnings:
+          print("WARNING")
+          print(warning["warning"])
+          if warning["file"]:
+            print("%s at line %d:" % (
+                file_lookup(warning["file"]), warning["lineno"]))
+            print(warning["line"])
+            print((" " * warning["charno"]) + "^")
+        print()
+
+      return True
+
+    return False
+
+  def write_output(self, target_filename, remove, json_data):
+      if "compiledCode" not in json_data:
+        print("FATAL ERROR: Compiler did not return compiledCode.")
+        sys.exit(1)
+
+      code = HEADER + "\n" + json_data["compiledCode"].decode("utf-8")
+      code = code.replace(remove, "")
+
+      # Trim down Google's (and only Google's) Apache licences.
+      # The Closure Compiler preserves these.
+      LICENSE = re.compile("""/\\*
+
+ [\\w ]+
+
+ Copyright \\d+ Google Inc.
+ https://developers.google.com/blockly/
+
+ Licensed under the Apache License, Version 2.0 \\(the "License"\\);
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+\\*/""")
+      code = re.sub(LICENSE, "", code)
+
+      stats = json_data["statistics"]
+      original_b = stats["originalSize"]
+      compressed_b = stats["compressedSize"]
+      if original_b > 0 and compressed_b > 0:
+        f = open(target_filename, "w")
+        f.write(code)
+        f.close()
+
+  def report_stats(self, target_filename, json_data):
+      stats = json_data["statistics"]
+      original_b = stats["originalSize"]
+      compressed_b = stats["compressedSize"]
+      if original_b > 0 and compressed_b > 0:
+        original_kb = int(original_b / 1024 + 0.5)
+        compressed_kb = int(compressed_b / 1024 + 0.5)
+        ratio = int(float(compressed_b) / float(original_b) * 100 + 0.5)
+        print("SUCCESS: " + target_filename)
+        print("Size changed from %d KB to %d KB (%d%%)." % (
+            original_kb, compressed_kb, ratio))
+      else:
+        print("UNKNOWN ERROR")
+
+
+class Gen_langfiles(threading.Thread):
+  """Generate JavaScript file for each natural language supported.
+
+  Runs in a separate thread.
+  """
+
+  def __init__(self):
+    threading.Thread.__init__(self)
+
+  def _rebuild(self, srcs, dests):
+    # Determine whether any of the files in srcs is newer than any in dests.
+    try:
+      return (max(os.path.getmtime(src) for src in srcs) >
+              min(os.path.getmtime(dest) for dest in dests))
+    except OSError as e:
+      # Was a file not found?
+      if e.errno == errno.ENOENT:
+        # If it was a source file, we can't proceed.
+        if e.filename in srcs:
+          print("Source file missing: " + e.filename)
+          sys.exit(1)
+        else:
+          # If a destination file was missing, rebuild.
+          return True
+      else:
+        print("Error checking file creation times: " + str(e))
+
+  def run(self):
+    # The files msg/json/{en,qqq,synonyms}.json depend on msg/messages.js.
+    if self._rebuild([os.path.join("msg", "messages.js")],
+                     [os.path.join("msg", "json", f) for f in
+                      ["en.json", "qqq.json", "synonyms.json"]]):
+      try:
+        subprocess.check_call([
+            "python",
+            os.path.join("i18n", "js_to_json.py"),
+            "--input_file", "msg/messages.js",
+            "--output_dir", "msg/json/",
+            "--quiet"])
+      except (subprocess.CalledProcessError, OSError) as e:
+        # Documentation for subprocess.check_call says that CalledProcessError
+        # will be raised on failure, but I found that OSError is also possible.
+        print("Error running i18n/js_to_json.py: ", e)
+        sys.exit(1)
+
+    # Checking whether it is necessary to rebuild the js files would be a lot of
+    # work since we would have to compare each <lang>.json file with each
+    # <lang>.js file.  Rebuilding is easy and cheap, so just go ahead and do it.
+    try:
+      # Use create_messages.py to create .js files from .json files.
+      cmd = [
+          "python",
+          os.path.join("i18n", "create_messages.py"),
+          "--source_lang_file", os.path.join("msg", "json", "en.json"),
+          "--source_synonym_file", os.path.join("msg", "json", "synonyms.json"),
+          "--source_constants_file", os.path.join("msg", "json", "constants.json"),
+          "--key_file", os.path.join("msg", "json", "keys.json"),
+          "--output_dir", os.path.join("msg", "js"),
+          "--quiet"]
+      json_files = glob.glob(os.path.join("msg", "json", "*.json"))
+      json_files = [file for file in json_files if not
+                    (file.endswith(("keys.json", "synonyms.json", "qqq.json", "constants.json")))]
+      cmd.extend(json_files)
+      subprocess.check_call(cmd)
+    except (subprocess.CalledProcessError, OSError) as e:
+      print("Error running i18n/create_messages.py: ", e)
+      sys.exit(1)
+
+    # Output list of .js files created.
+    for f in json_files:
+      # This assumes the path to the current directory does not contain "json".
+      f = f.replace("json", "js")
+      if os.path.isfile(f):
+        print("SUCCESS: " + f)
+      else:
+        print("FAILED to create " + f)
+
+def exclude_vertical(item):
+  return not item.endswith("block_render_svg_vertical.js")
+
+def exclude_horizontal(item):
+  return not item.endswith("block_render_svg_horizontal.js")
+
+if __name__ == "__main__":
+  try:
+    closure_dir = CLOSURE_DIR_NPM
+    closure_root = CLOSURE_ROOT_NPM
+    closure_library = CLOSURE_LIBRARY_NPM
+    closure_compiler = CLOSURE_COMPILER_NPM
+
+    # Load calcdeps from the local library
+    calcdeps = import_path(os.path.join(
+        closure_root, closure_library, "closure", "bin", "calcdeps.py"))
+
+    # Sanity check the local compiler
+    test_args = [closure_compiler, os.path.join("build", "test_input.js")]
+    test_proc = subprocess.Popen(test_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    (stdout, _) = test_proc.communicate()
+    assert stdout.decode("utf-8") == read(os.path.join("build", "test_expect.js"))
+
+    print("Using local compiler: %s ...\n" % CLOSURE_COMPILER_NPM)
+  except (ImportError, AssertionError):
+    if os.path.isdir(os.path.join(os.path.pardir, "closure-library-read-only")):
+      # Dir got renamed when Closure moved from Google Code to GitHub in 2014.
+      print("Error: Closure directory needs to be renamed from"
+            "'closure-library-read-only' to 'closure-library'.\n"
+            "Please rename this directory.")
+    elif os.path.isdir(os.path.join(os.path.pardir, "google-closure-library")):
+      print("Error: Closure directory needs to be renamed from"
+            "'google-closure-library' to 'closure-library'.\n"
+            "Please rename this directory.")
+    else:
+      print("""Error: Closure not found. Usually this means 'npm ci' failed. Try running it again? More resources:
+  developers.google.com/blockly/guides/modify/web/closure""")
+      sys.exit(1)
+
+  search_paths = list(calcdeps.ExpandDirectories(
+      ["core", os.path.join(closure_root, closure_library)]))
+
+  search_paths_horizontal = list(filter(exclude_vertical, search_paths))
+  search_paths_vertical = list(filter(exclude_horizontal, search_paths))
+
+  closure_env = {
+    "closure_dir": closure_dir,
+    "closure_root": closure_root,
+    "closure_library": closure_library,
+    "closure_compiler": closure_compiler,
+  }
+
+  # Run all tasks in parallel threads.
+  # Uncompressed is limited by processor speed.
+  # Compressed is limited by network and server speed.
+  threads = [
+    # Vertical:
+    Gen_uncompressed(search_paths_vertical, True, closure_env),
+    # Horizontal:
+    Gen_uncompressed(search_paths_horizontal, False, closure_env),
+    # Compressed forms of vertical and horizontal.
+    Gen_compressed(search_paths_vertical, search_paths_horizontal, closure_env),
+
+    # This is run locally in a separate thread.
+    # Gen_langfiles()
+  ]
+
+  for thread in threads:
+    thread.start()
+
+  # Need to wait for all threads to finish before the main process ends as in Python 3.12,
+  # once the main interpreter is being shutdown, trying to spawn more child threads will
+  # raise "RuntimeError: can't create new thread at interpreter shutdown"
+  for thread in threads:
+    thread.join()