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

compile

Index: compile
===================================================================
new file mode 100755
--- /dev/null
+++ b/compile
@@ -0,0 +1,273 @@
+#!/usr/bin/env python
+
+import json
+import os
+import re
+import subprocess
+import warnings
+
+EMSCRIPTEN_PATH = '../emscripten'
+SOURCE_DIR = './compiled'
+SOURCE_FILES = [
+  os.path.join(SOURCE_DIR, f)
+  for f in os.listdir(SOURCE_DIR)
+  if f.endswith('.cpp')
+]
+API_FILE = os.path.join(SOURCE_DIR, 'api.cpp')
+API_OUTPUT = os.path.join(SOURCE_DIR, 'api.js')
+COMPILER_OUTPUT = './lib/compiled.js'
+GENERATION_PARAMS = {
+  'SHELL_FILE': "'%s'" % os.path.abspath(os.path.join(SOURCE_DIR, 'shell.js')),
+  'TOTAL_MEMORY': 16*1024*1024,
+  'TOTAL_STACK': 1*1024*1024,
+  'ALLOW_MEMORY_GROWTH': 1,
+  'NO_EXIT_RUNTIME': 1,
+  'DISABLE_EXCEPTION_CATCHING': 0,
+  'NO_DYNAMIC_EXECUTION': 1,
+  'NO_BROWSER': 1,
+  'NO_FILESYSTEM': 1,
+  'INVOKE_RUN': 0,
+  'NODE_STDOUT_FLUSH_WORKAROUND': 0,
+}
+DEFINES = ['DEBUG']
+ADDITIONAL_PARAMS = ['-O3', '-m32', '-std=gnu++11', '--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')])
+  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)
+  return env
+
+def generate_api(env):
+  params = [os.path.join(env['EMSCRIPTEN'], 'emcc'), '-E', API_FILE]
+  params.extend(ADDITIONAL_PARAMS)
+  output = subprocess.check_output(params, env=env)
+
+  differentiators = {}
+  differentiator = None
+
+  cls = None
+  method = None
+
+  def wrap_call(func, is_instance, result_type, string_args, arg_count=10):
+    params = ['arg%i' % i for i in range(arg_count)]
+    prefix = '''\
+function(%s)
+{
+''' % ', '.join(params)
+    suffix = '''\
+  return result;
+}'''
+
+    if result_type == 'string' or len(string_args):
+      prefix += '  var sp = Runtime.stackSave();\n'
+      suffix = '  Runtime.stackRestore(sp);\n' + suffix
+
+    for pos in string_args:
+      params[pos] = 'createString(%s)' % params[pos]
+
+    if is_instance:
+      params.insert(0, 'this._pointer')
+
+    if result_type == 'primitive':
+      prefix += '  var result = _%s(%s);\n' % (func, ', '.join(params))
+    elif result_type == 'string':
+      prefix += '  var result = createString();\n'
+      params.insert(0, 'result')
+      prefix += '  _%s(%s);\n' % (func, ', '.join(params))
+      prefix += '  result = getStringData(result);\n'
+    else:
+      prefix += '  var pointer = _%s(%s);\n' % (func, ', '.join(params))
+      if result_type in differentiators:
+        prefix += '  var type = _%s(pointer);\n' % differentiator['func']
+        prefix += '  if (type in %s_mapping)\n' % result_type
+        prefix += '    var result = new (exports[%s_mapping[type]])(pointer);\n' % result_type
+        prefix += '  else\n'
+        prefix += '    throw new Error("Unexpected %s type: " + type);\n' % result_type
+      else:
+        prefix += '  var result = %s(pointer);\n' % result_type
+
+    return prefix + suffix
+
+  def property_descriptor(property):
+    if property['type'] == 'static':
+      return 'value: %s' % property['getter']
+
+    result = 'get: %s' % wrap_call(
+      property['getter'], is_instance=True, result_type=property['type'],
+      string_args=[], arg_count=0
+    )
+    if property['setter'] is not None:
+      result += ', set: %s' % wrap_call(
+        property['setter'], is_instance=True, result_type='primitive',
+        string_args=[0] if property['type'] == 'string' else [],
+        arg_count=1
+      )
+    return result
+
+  def method_descriptor(method):
+    return wrap_call(
+      method['func'], is_instance=(method['type'] == 'instance'),
+      result_type=method['result'], string_args=method['string_args']
+    )
+
+  def write_class(file, cls):
+    name = cls['name']
+    if name in differentiators:
+      print >>file, 'var %s_mapping = %s;' % (
+          name, json.dumps(differentiators[name]['mapping'], sort_keys=True))
+
+    print >>file, 'exports.%s = createClass(%s);' % (
+        name, 'exports.' + cls['superclass'] if cls['superclass'] else '')
+    for property in cls['properties']:
+      print >>file, 'Object.defineProperty(exports.%s.prototype, "%s", {%s});' % (
+          name, property['name'], property_descriptor(property))
+    for method in cls['methods']:
+      obj = ('exports.%s' if method['type'] == 'class' else 'exports.%s.prototype') % name
+      print >>file, '%s.%s = %s;' % (
+          obj, method['name'], method_descriptor(method))
+    for initializer in cls['class_initializers']:
+      print >>file, '_%s();' % initializer
+
+  def handle_class(name):
+    if cls is not None:
+      write_class(file, cls)
+    differentiator = None
+    return {
+      'name': command[1],
+      'superclass': None,
+      'properties': [],
+      'methods': [],
+      'class_initializers': [],
+    }
+
+  def handle_superclass(name):
+    if cls is None:
+      warnings.warn('Superclass declared outside a class: ' + name)
+      return
+    differentiator = None
+    cls['superclass'] = name
+
+  def handle_class_init(func):
+    if cls is None:
+      warnings.warn('Class initializer declared outside a class: ' + func)
+      return
+    differentiator = None
+    method = None
+    cls['class_initializers'].append(func)
+
+  def handle_differentiator(cls, func):
+    differentiator = {'func': func, 'mapping': {}}
+    differentiators[cls] = differentiator
+    return differentiator
+
+  def handle_differentiator_mapping(value, subclass):
+    if differentiator is None:
+      warnings.warn('Differentiator mapping declared without a differentiator: ' + subclass)
+      return
+    differentiator['mapping'][value] = subclass
+
+  def handle_property(type, name, getter, setter):
+    if cls is None:
+      warnings.warn('Property declared outside a class: ' + name)
+      return
+    method = None
+    differentiator = None
+    cls['properties'].append({
+      'type': type,
+      'name': name,
+      'getter': getter,
+      'setter': setter,
+    })
+
+  def handle_method(type, name, func):
+    if cls is None:
+      warnings.warn('Method declared outside a class: ' + name)
+      return
+    differentiator = None
+    method = {
+      'type': type,
+      'name': name,
+      'func': func,
+      'result': 'primitive',
+      'string_args': [],
+    }
+    cls['methods'].append(method)
+    return method
+
+  def handle_method_result(type):
+    if method is None:
+      warnings.warn('Method result declared without a method definition')
+      return
+    method['result'] = type
+
+  def handle_string_arg(pos):
+    if method is None:
+      warnings.warn('Argument type declared without a method definition')
+      return
+    method['string_args'].append(int(pos))
+
+  with open(API_OUTPUT, 'w') as file:
+    for line in output.splitlines():
+      match = re.search(r'#pragma\s+comment\((.+?)\)', line)
+      if match:
+        command = match.group(1).strip().split()
+        if command[0] == 'class':
+          cls = handle_class(command[1])
+        elif command[0] == 'augments':
+          handle_superclass(command[1])
+        elif command[0] == 'class_init':
+          handle_class_init(command[1])
+        elif command[0] == 'differentiator':
+          differentiator = handle_differentiator(command[1], command[2])
+        elif command[0] == 'differentiator_mapping':
+          handle_differentiator_mapping(command[1], command[2])
+        elif command[0] == 'property':
+          handle_property('primitive', command[1], command[2], command[3] if len(command) > 3 else None)
+        elif command[0] == 'string_property':
+          handle_property('string', command[1], command[2], command[3] if len(command) > 3 else None)
+        elif command[0] == 'static_property':
+          handle_property('static', command[1], command[2], None)
+        elif command[0] == 'method':
+          method = handle_method('instance', command[1], command[2])
+        elif command[0] == 'class_method':
+          method = handle_method('class', command[1], command[2])
+        elif command[0] == 'string_result':
+          handle_method_result('string')
+        elif command[0] == 'pointer_result':
+          handle_method_result(command[1])
+        elif command[0] == 'string_arg':
+          handle_string_arg(command[1])
+        else:
+          warnings.warn('Unknown declaration: ' + str(command))
+
+    if cls is not None:
+      write_class(file, cls)
+
+def run_compiler(env):
+  params = [
+    os.path.join(env['EMSCRIPTEN'], 'emcc'),
+    '-o', COMPILER_OUTPUT,
+    '--post-js', API_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_api(env)
+  run_compiler(env)