Issue 4125 - [emscripten] Convert filter classes to C++

compile

 #!/usr/bin/env python
 
 import json
 import os
 import re
 import subprocess
 import warnings
 
 EMSCRIPTEN_PATH = '../emscripten'
 SOURCE_DIR = './compiled'
@@ skipping 20 matching lines @@
   'NODE_STDOUT_FLUSH_WORKAROUND': 0,
 }
 DEFINES = []
 ADDITIONAL_PARAMS = ['-O3', '-m32', '-std=gnu++14', '--memory-init-file', '0',
     '--emit-symbol-map']
 
 def getenv():
   path = []
   env = {}
   output = subprocess.check_output([
-      '/bin/sh', '-c', os.path.join(EMSCRIPTEN_PATH, 'emsdk_env.sh')])
+      '/bin/bash', '-c', os.path.join(EMSCRIPTEN_PATH, 'emsdk_env.sh')])
   for line in output.splitlines():
     match = re.search(r'^\s*PATH\s*\+=\s*(.*)', line)
     if match:
       path.append(match.group(1))
     match = re.search(r'^\s*(\w+)\s*=\s*(.*)', line)
     if match:
       env[match.group(1)] = match.group(2)
-  env['PATH'] = ':'.join([os.environ['PATH']] + path)
+  env['PATH'] = os.pathsep.join([os.environ['PATH']] + path)
   return env
 
 def generate_bindings(env):
   params = [os.path.join(env['EMSCRIPTEN'], 'emcc'), BINDINGS_FILE,
     '-o', BINDINGS_GENERATOR, '-std=gnu++14', '-DPRINT_BINDINGS',
-    '-s', 'SAFE_HEAP=1', '-s', 'WARN_ON_UNDEFINED_SYMBOLS=0',
+    '-s', 'WARN_ON_UNDEFINED_SYMBOLS=0',
   ]
   subprocess.check_call(params, env=env)
 
   node = subprocess.check_output('which node', env=env, shell=True).strip();
   with open(BINDINGS_OUTPUT, 'w') as file:
     subprocess.check_call([node, BINDINGS_GENERATOR], env=env, stdout=file)
 
 def run_compiler(env):
   params = [
     os.path.join(env['EMSCRIPTEN'], 'emcc'),
     '-o', COMPILER_OUTPUT,
     '--post-js', BINDINGS_OUTPUT,
   ]
   params.extend(SOURCE_FILES)
   params.extend('-D' + flag for flag in DEFINES)
   for key, value in GENERATION_PARAMS.iteritems():
     params.extend(['-s', '%s=%s' % (key, str(value))])
   params.extend(ADDITIONAL_PARAMS)
   subprocess.check_call(params, env=env)
 
 if __name__ == '__main__':
   env = getenv()
   generate_bindings(env)
   run_compiler(env)