js2c.py

#!/usr/bin/env python
#
# Copyright 2006-2008 the V8 project authors. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#     * Neither the name of Google Inc. nor the names of its
#       contributors may be used to endorse or promote products derived
#       from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# This is a utility for converting JavaScript source code into C-style
# char arrays. It is used for embedded JavaScript code in the V8
# library.

import os
import re
import sys


def ToCArray(elements, step=10):
  slices = (elements[i:i+step] for i in range(0, len(elements), step))
  slices = map(lambda s: ','.join(str(x) for x in s), slices)
  return ',\n'.join(slices)

def ReadFile(filename):
  file = open(filename, "rt")
  try:
    lines = file.read()
  finally:
    file.close()
  return lines


def ReadLines(filename):
  result = []
  for line in open(filename, "rt"):
    if '#' in line:
      line = line[:line.index('#')]
    line = line.strip()
    if len(line) > 0:
      result.append(line)
  return result


def ExpandConstants(lines, constants):
  for key, value in constants.items():
    lines = lines.replace(key, str(value))
  return lines


def ExpandMacros(lines, macros):
  def expander(s):
    return ExpandMacros(s, macros)
  for name, macro in macros.items():
    name_pattern = re.compile("\\b%s\\(" % name)
    pattern_match = name_pattern.search(lines, 0)
    while pattern_match is not None:
      # Scan over the arguments
      height = 1
      start = pattern_match.start()
      end = pattern_match.end()
      assert lines[end - 1] == '('
      last_match = end
      arg_index = [0]  # Wrap state into array, to work around Python "scoping"
      mapping = {}
      def add_arg(str):
        # Remember to expand recursively in the arguments
        if arg_index[0] >= len(macro.args):
          return
        replacement = expander(str.strip())
        mapping[macro.args[arg_index[0]]] = replacement
        arg_index[0] += 1
      while end < len(lines) and height > 0:
        # We don't count commas at higher nesting levels.
        if lines[end] == ',' and height == 1:
          add_arg(lines[last_match:end])
          last_match = end + 1
        elif lines[end] in ['(', '{', '[']:
          height = height + 1
        elif lines[end] in [')', '}', ']']:
          height = height - 1
        end = end + 1
      # Remember to add the last match.
      add_arg(lines[last_match:end-1])
      if arg_index[0] < len(macro.args) -1:
        lineno = lines.count(os.linesep, 0, start) + 1
        raise Exception('line %s: Too few arguments for macro "%s"' % (lineno, name))
      result = macro.expand(mapping)
      # Replace the occurrence of the macro with the expansion
      lines = lines[:start] + result + lines[end:]
      pattern_match = name_pattern.search(lines, start + len(result))
  return lines


class TextMacro:
  def __init__(self, args, body):
    self.args = args
    self.body = body
  def expand(self, mapping):
    result = self.body
    for key, value in mapping.items():
        result = result.replace(key, value)
    return result

class PythonMacro:
  def __init__(self, args, fun):
    self.args = args
    self.fun = fun
  def expand(self, mapping):
    args = []
    for arg in self.args:
      args.append(mapping[arg])
    return str(self.fun(*args))

CONST_PATTERN = re.compile('^const\s+([a-zA-Z0-9_]+)\s*=\s*([^;]*);$')
MACRO_PATTERN = re.compile('^macro\s+([a-zA-Z0-9_]+)\s*\(([^)]*)\)\s*=\s*([^;]*);$')
PYTHON_MACRO_PATTERN = re.compile('^python\s+macro\s+([a-zA-Z0-9_]+)\s*\(([^)]*)\)\s*=\s*([^;]*);$')

def ReadMacros(lines):
  constants = { }
  macros = { }
  for line in lines:
    hash = line.find('#')
    if hash != -1: line = line[:hash]
    line = line.strip()
    if len(line) == 0:
      continue
    const_match = CONST_PATTERN.match(line)
    if const_match:
      name = const_match.group(1)
      value = const_match.group(2).strip()
      constants[name] = value
    else:
      macro_match = MACRO_PATTERN.match(line)
      if macro_match:
        name = macro_match.group(1)
        args = [s.strip() for s in macro_match.group(2).split(',')]
        body = macro_match.group(3).strip()
        macros[name] = TextMacro(args, body)
      else:
        python_match = PYTHON_MACRO_PATTERN.match(line)
        if python_match:
          name = python_match.group(1)
          args = [s.strip() for s in python_match.group(2).split(',')]
          body = python_match.group(3).strip()
          fun = eval("lambda " + ",".join(args) + ': ' + body)
          macros[name] = PythonMacro(args, fun)
        else:
          raise Exception("Illegal line: " + line)
  return (constants, macros)


TEMPLATE = """
#include "node_native_module.h"
#include "node_internals.h"

namespace node {{

namespace native_module {{

{definitions}

void NativeModuleLoader::LoadJavaScriptSource() {{
  {initializers}
}}

UnionBytes NativeModuleLoader::GetConfig() {{
  return UnionBytes(config_raw, arraysize(config_raw));  // config.gypi
}}

}}  // namespace native_module

}}  // namespace node
"""

ONE_BYTE_STRING = """
static const uint8_t {var}[] = {{ {data} }};
"""

TWO_BYTE_STRING = """
static const uint16_t {var}[] = {{ {data} }};
"""


INITIALIZER = """
source_.emplace(
    "{module}",
    UnionBytes({var}, arraysize({var}))
);
"""

def JS2C(source, target):
  modules = []
  consts = {}
  macros = {}
  macro_lines = []

  for s in source:
    if (os.path.split(str(s))[1]).endswith('macros.py'):
      macro_lines.extend(ReadLines(str(s)))
    else:
      modules.append(s)

  # Process input from all *macro.py files
  (consts, macros) = ReadMacros(macro_lines)

  # Build source code lines
  definitions = []
  initializers = []

  def GetDefinition(var, source):
    # Treat non-ASCII as UTF-8 and convert it to UTF-16.
    if any(ord(c) > 127 for c in source):
      source = map(ord, source.decode('utf-8').encode('utf-16be'))
      source = [source[i] * 256 + source[i+1] for i in range(0, len(source), 2)]
      source = ToCArray(source)
      return TWO_BYTE_STRING.format(var=var, data=source)
    else:
      source = ToCArray(map(ord, source), step=20)
      return ONE_BYTE_STRING.format(var=var, data=source)

  def AddModule(module, source):
    var = '%s_raw' % (module.replace('-', '_').replace('/', '_'))
    definition = GetDefinition(var, source)
    initializer = INITIALIZER.format(module=module,
                                     var=var)
    definitions.append(definition)
    initializers.append(initializer)

  for name in modules:
    lines = ReadFile(str(name))
    lines = ExpandConstants(lines, consts)
    lines = ExpandMacros(lines, macros)

    # On Windows, "./foo.bar" in the .gyp file is passed as "foo.bar"
    # so don't assume there is always a slash in the file path.
    if '/' in name or '\\' in name:
      split = re.split('/|\\\\', name)
      if split[0] == 'deps':
        split = ['internal'] + split
      else:
        split = split[1:]
      name = '/'.join(split)

    # if its a gypi file we're going to want it as json
    # later on anyway, so get it out of the way now
    if name.endswith('.gypi'):
      # Currently only config.gypi is allowed
      assert name == 'config.gypi'
      lines = re.sub(r'\'true\'', 'true', lines)
      lines = re.sub(r'\'false\'', 'false', lines)
      lines = re.sub(r'#.*?\n', '', lines)
      lines = re.sub(r'\'', '"', lines)
      definition = GetDefinition('config_raw', lines)
      definitions.append(definition)
    else:
      AddModule(name.split('.', 1)[0], lines)

  # Emit result
  output = open(str(target[0]), "w")
  output.write(
    TEMPLATE.format(definitions=''.join(definitions),
                    initializers=''.join(initializers)))
  output.close()

def main():
  natives = sys.argv[1]
  source_files = sys.argv[2:]
  if source_files[-2] == '-t':
    global TEMPLATE
    TEMPLATE = source_files[-1]
    source_files = source_files[:-2]
  JS2C(source_files, [natives])

if __name__ == "__main__":
  main()