system_libs.py

import os, json, logging, zipfile, glob
import shared
from subprocess import Popen, CalledProcessError
import multiprocessing
from tools.shared import check_call

stdout = None
stderr = None

def call_process(cmd):
  proc = Popen(cmd, stdout=stdout, stderr=stderr)
  proc.communicate()
  if proc.returncode != 0:
    # Deliberately do not use CalledProcessError, see issue #2944
    raise Exception('Command \'%s\' returned non-zero exit status %s' % (' '.join(cmd), proc.returncode))

CORES = int(os.environ.get('EMCC_CORES') or multiprocessing.cpu_count())

def run_commands(commands):
  cores = min(len(commands), CORES)
  if cores <= 1:
    for command in commands:
      call_process(command)
  else:
    pool = multiprocessing.Pool(processes=cores)
    pool.map(call_process, commands, chunksize=1)

def calculate(temp_files, in_temp, stdout_, stderr_, forced=[]):
  global stdout, stderr
  stdout = stdout_
  stderr = stderr_

  # Check if we need to include some libraries that we compile. (We implement libc ourselves in js, but
  # compile a malloc implementation and stdlibc++.)

  def read_symbols(path, exclude=None):
    symbols = map(lambda line: line.strip().split(' ')[1], open(path).readlines())
    if exclude:
      symbols = filter(lambda symbol: symbol not in exclude, symbols)
    return set(symbols)

  default_opts = []

  # XXX We also need to add libc symbols that use malloc, for example strdup. It's very rare to use just them and not
  #     a normal malloc symbol (like free, after calling strdup), so we haven't hit this yet, but it is possible.
  libc_symbols = read_symbols(shared.path_from_root('system', 'lib', 'libc.symbols'))
  libcxx_symbols = read_symbols(shared.path_from_root('system', 'lib', 'libcxx', 'symbols'), exclude=libc_symbols)
  libcxxabi_symbols = read_symbols(shared.path_from_root('system', 'lib', 'libcxxabi', 'symbols'), exclude=libc_symbols)
  gl_symbols = read_symbols(shared.path_from_root('system', 'lib', 'gl.symbols'))
  pthreads_symbols = read_symbols(shared.path_from_root('system', 'lib', 'pthreads.symbols'))

  # XXX we should disable EMCC_DEBUG when building libs, just like in the relooper

  def build_libc(lib_filename, files, lib_opts):
    o_s = []
    musl_internal_includes = ['-I', shared.path_from_root('system', 'lib', 'libc', 'musl', 'src', 'internal'), '-I', shared.path_from_root('system', 'lib', 'libc', 'musl', 'arch', 'js')]
    commands = []
    # Hide several musl warnings that produce a lot of spam to unit test build server logs.
    # TODO: When updating musl the next time, feel free to recheck which of their warnings might have been fixed, and which ones of these could be cleaned up.
    c_opts = ['-Wno-dangling-else', '-Wno-unknown-pragmas', '-Wno-shift-op-parentheses', '-Wno-string-plus-int', '-Wno-logical-op-parentheses', '-Wno-bitwise-op-parentheses', '-Wno-visibility', '-Wno-pointer-sign']
    for src in files:
      o = in_temp(os.path.basename(src) + '.o')
      commands.append([shared.PYTHON, shared.EMCC, shared.path_from_root('system', 'lib', src), '-o', o] + musl_internal_includes + default_opts + c_opts + lib_opts)
      o_s.append(o)
    run_commands(commands)
    shared.Building.link(o_s, in_temp(lib_filename))
    return in_temp(lib_filename)

  def build_libcxx(src_dirname, lib_filename, files, lib_opts, has_noexcept_version=False):
    o_s = []
    commands = []
    opts = default_opts + lib_opts
    if has_noexcept_version and shared.Settings.DISABLE_EXCEPTION_CATCHING:
      opts += ['-fno-exceptions']
    for src in files:
      o = in_temp(src + '.o')
      srcfile = shared.path_from_root(src_dirname, src)
      commands.append([shared.PYTHON, shared.EMXX, srcfile, '-o', o, '-std=c++11'] + opts)
      o_s.append(o)
    run_commands(commands)
    if lib_filename.endswith('.bc'):
      shared.Building.link(o_s, in_temp(lib_filename))
    elif lib_filename.endswith('.a'):
      shared.Building.emar('cr', in_temp(lib_filename), o_s)
    else:
      raise Exception('unknown suffix ' + lib_filename)
    return in_temp(lib_filename)

  # libc
  def create_libc(libname):
    logging.debug(' building libc for cache')
    libc_files = [
    ]
    musl_srcdir = shared.path_from_root('system', 'lib', 'libc', 'musl', 'src')
    blacklist = set(
      ['ipc', 'passwd', 'thread', 'signal', 'sched', 'ipc', 'time', 'linux', 'aio', 'exit', 'legacy', 'mq', 'process', 'search', 'setjmp', 'env', 'ldso', 'conf'] + # musl modules
      ['memcpy.c', 'memset.c', 'memmove.c', 'getaddrinfo.c', 'getnameinfo.c', 'inet_addr.c', 'res_query.c', 'gai_strerror.c', 'proto.c', 'gethostbyaddr.c', 'gethostbyaddr_r.c', 'gethostbyname.c', 'gethostbyname2_r.c', 'gethostbyname_r.c', 'gethostbyname2.c', 'usleep.c', 'alarm.c', 'syscall.c'] + # individual files
      ['abs.c', 'cos.c', 'cosf.c', 'cosl.c', 'sin.c', 'sinf.c', 'sinl.c', 'tan.c', 'tanf.c', 'tanl.c', 'acos.c', 'acosf.c', 'acosl.c', 'asin.c', 'asinf.c', 'asinl.c', 'atan.c', 'atanf.c', 'atanl.c', 'atan2.c', 'atan2f.c', 'atan2l.c', 'exp.c', 'expf.c', 'expl.c', 'log.c', 'logf.c', 'logl.c', 'sqrt.c', 'sqrtf.c', 'sqrtl.c', 'fabs.c', 'fabsf.c', 'fabsl.c', 'ceil.c', 'ceilf.c', 'ceill.c', 'floor.c', 'floorf.c', 'floorl.c', 'pow.c', 'powf.c', 'powl.c'] # individual math files
    )
    # TODO: consider using more math code from musl, doing so makes box2d faster
    for dirpath, dirnames, filenames in os.walk(musl_srcdir):
      for f in filenames:
        if f.endswith('.c'):
          if f in blacklist: continue
          dir_parts = os.path.split(dirpath)
          cancel = False
          for part in dir_parts:
            if part in blacklist:
              cancel = True
              break
          if not cancel:
            libc_files.append(os.path.join(musl_srcdir, dirpath, f))
    args = ['-Os']
    if shared.Settings.USE_PTHREADS:
      args += ['-s', 'USE_PTHREADS=1']
      assert '-mt' in libname
    else:
      assert '-mt' not in libname
    return build_libc(libname, libc_files, args)

  def create_pthreads(libname):
    # Add pthread files.
    pthreads_files = [os.path.join('pthread', 'library_pthread.c')]
    pthreads_files += [shared.path_from_root('system', 'lib', 'libc', 'musl', 'src', 'thread', x) for x in ('pthread_attr_destroy.c', 'pthread_condattr_setpshared.c', 'pthread_mutex_lock.c', 'pthread_spin_destroy.c', 'pthread_attr_get.c', 'pthread_cond_broadcast.c', 'pthread_mutex_setprioceiling.c', 'pthread_spin_init.c', 'pthread_attr_init.c', 'pthread_cond_destroy.c', 'pthread_mutex_timedlock.c', 'pthread_spin_lock.c', 'pthread_attr_setdetachstate.c', 'pthread_cond_init.c', 'pthread_mutex_trylock.c', 'pthread_spin_trylock.c', 'pthread_attr_setguardsize.c', 'pthread_cond_signal.c', 'pthread_mutex_unlock.c', 'pthread_spin_unlock.c', 'pthread_attr_setinheritsched.c', 'pthread_cond_timedwait.c', 'pthread_once.c', 'sem_destroy.c', 'pthread_attr_setschedparam.c', 'pthread_cond_wait.c', 'pthread_rwlockattr_destroy.c', 'sem_getvalue.c', 'pthread_attr_setschedpolicy.c', 'pthread_equal.c', 'pthread_rwlockattr_init.c', 'sem_init.c', 'pthread_attr_setscope.c', 'pthread_getspecific.c', 'pthread_rwlockattr_setpshared.c', 'sem_open.c', 'pthread_attr_setstack.c', 'pthread_key_create.c', 'pthread_rwlock_destroy.c', 'sem_post.c', 'pthread_attr_setstacksize.c', 'pthread_mutexattr_destroy.c', 'pthread_rwlock_init.c', 'sem_timedwait.c', 'pthread_barrierattr_destroy.c', 'pthread_mutexattr_init.c', 'pthread_rwlock_rdlock.c', 'sem_trywait.c', 'pthread_barrierattr_init.c', 'pthread_mutexattr_setprotocol.c', 'pthread_rwlock_timedrdlock.c', 'sem_unlink.c', 'pthread_barrierattr_setpshared.c', 'pthread_mutexattr_setpshared.c', 'pthread_rwlock_timedwrlock.c', 'sem_wait.c', 'pthread_barrier_destroy.c', 'pthread_mutexattr_setrobust.c', 'pthread_rwlock_tryrdlock.c', '__timedwait.c', 'pthread_barrier_init.c', 'pthread_mutexattr_settype.c', 'pthread_rwlock_trywrlock.c', 'vmlock.c', 'pthread_barrier_wait.c', 'pthread_mutex_consistent.c', 'pthread_rwlock_unlock.c', '__wait.c', 'pthread_condattr_destroy.c', 'pthread_mutex_destroy.c', 'pthread_rwlock_wrlock.c', 'pthread_condattr_init.c', 'pthread_mutex_getprioceiling.c', 'pthread_setcanceltype.c', 'pthread_condattr_setclock.c', 'pthread_mutex_init.c', 'pthread_setspecific.c')]
    return build_libc(libname, pthreads_files, ['-O2', '-s', 'USE_PTHREADS=1'])

  # libcxx
  def create_libcxx(libname):
    logging.debug('building libcxx for cache')
    libcxx_files = [
      'algorithm.cpp',
      'condition_variable.cpp',
      'future.cpp',
      'iostream.cpp',
      'memory.cpp',
      'random.cpp',
      'stdexcept.cpp',
      'system_error.cpp',
      'utility.cpp',
      'bind.cpp',
      'debug.cpp',
      'hash.cpp',
      'mutex.cpp',
      'string.cpp',
      'thread.cpp',
      'valarray.cpp',
      'chrono.cpp',
      'exception.cpp',
      'ios.cpp',
      'locale.cpp',
      'regex.cpp',
      'strstream.cpp'
    ]
    return build_libcxx(os.path.join('system', 'lib', 'libcxx'), libname, libcxx_files, ['-Oz', '-I' + shared.path_from_root('system', 'lib', 'libcxxabi', 'include')], has_noexcept_version=True)

  # libcxxabi - just for dynamic_cast for now
  def create_libcxxabi(libname):
    logging.debug('building libcxxabi for cache')
    libcxxabi_files = [
      'abort_message.cpp',
      'cxa_aux_runtime.cpp',
      'cxa_default_handlers.cpp',
      'cxa_demangle.cpp',
      'cxa_exception_storage.cpp',
      'cxa_new_delete.cpp',
      'cxa_handlers.cpp',
      'exception.cpp',
      'stdexcept.cpp',
      'typeinfo.cpp',
      'private_typeinfo.cpp',
      os.path.join('..', '..', 'libcxx', 'new.cpp'),
    ]
    return build_libcxx(os.path.join('system', 'lib', 'libcxxabi', 'src'), libname, libcxxabi_files, ['-Oz', '-I' + shared.path_from_root('system', 'lib', 'libcxxabi', 'include')])

  # gl
  def create_gl(libname): # libname is ignored, this is just one .o file
    o = in_temp('gl.o')
    check_call([shared.PYTHON, shared.EMCC, shared.path_from_root('system', 'lib', 'gl.c'), '-o', o])
    return o

  def create_dlmalloc(out_name, clflags):
    o = in_temp(out_name)
    check_call([shared.PYTHON, shared.EMCC, shared.path_from_root('system', 'lib', 'dlmalloc.c'), '-o', o] + clflags)
    return o

  def create_dlmalloc_singlethreaded(libname):
    return create_dlmalloc(libname, ['-O2'])

  def create_dlmalloc_singlethreaded_tracing(libname):
    return create_dlmalloc(libname, ['-O2', '--tracing'])

  def create_dlmalloc_multithreaded(libname):
    return create_dlmalloc(libname, ['-O2', '-s', 'USE_PTHREADS=1'])

  def create_dlmalloc_multithreaded_tracing(libname):
    return create_dlmalloc(libname, ['-O2', '-s', 'USE_PTHREADS=1', '--tracing'])

  def create_dlmalloc_split(libname):
    dlmalloc_o = in_temp('dl' + libname)
    check_call([shared.PYTHON, shared.EMCC, shared.path_from_root('system', 'lib', 'dlmalloc.c'), '-o', dlmalloc_o, '-O2', '-DMSPACES', '-DONLY_MSPACES'])
    split_malloc_o = in_temp('sm' + libname)
    check_call([shared.PYTHON, shared.EMCC, shared.path_from_root('system', 'lib', 'split_malloc.cpp'), '-o', split_malloc_o, '-O2'])
    lib = in_temp(libname)
    shared.Building.link([dlmalloc_o, split_malloc_o], lib)
    return lib

  # Setting this in the environment will avoid checking dependencies and make building big projects a little faster
  # 1 means include everything; otherwise it can be the name of a lib (libcxx, etc.)
  # You can provide 1 to include everything, or a comma-separated list with the ones you want
  force = os.environ.get('EMCC_FORCE_STDLIBS')
  force_all = force == '1'
  force = set((force.split(',') if force else []) + forced)
  if force: logging.debug('forcing stdlibs: ' + str(force))

  # Setting this will only use the forced libs in EMCC_FORCE_STDLIBS. This avoids spending time checking
  # for unresolved symbols in your project files, which can speed up linking, but if you do not have
  # the proper list of actually needed libraries, errors can occur. See below for how we must
  # export all the symbols in deps_info when using this option.
  only_forced = os.environ.get('EMCC_ONLY_FORCED_STDLIBS')
  if only_forced:
    temp_files = []

  # Add in some hacks for js libraries. If a js lib depends on a symbol provided by a C library, it must be
  # added to here, because our deps go only one way (each library here is checked, then we check the next
  # in order - libcxx, libcxextra, etc. - and then we run the JS compiler and provide extra symbols from
  # library*.js files. But we cannot then go back to the C libraries if a new dep was added!
  # TODO: Move all __deps from src/library*.js to deps_info.json, and use that single source of info
  #       both here and in the JS compiler.
  deps_info = json.loads(open(shared.path_from_root('src', 'deps_info.json')).read())
  added = set()
  def add_back_deps(need):
    more = False
    for ident, deps in deps_info.iteritems():
      if ident in need.undefs and not ident in added:
        added.add(ident)
        more = True
        for dep in deps:
          need.undefs.add(dep)
          shared.Settings.EXPORTED_FUNCTIONS.append('_' + dep)
    if more:
      add_back_deps(need) # recurse to get deps of deps

  # Scan symbols
  symbolses = map(lambda temp_file: shared.Building.llvm_nm(temp_file), temp_files)

  if len(symbolses) == 0:
    class Dummy:
      defs = set()
      undefs = set()
    symbolses.append(Dummy())

  # depend on exported functions
  for export in shared.Settings.EXPORTED_FUNCTIONS:
    if shared.Settings.VERBOSE: logging.debug('adding dependency on export %s' % export)
    symbolses[0].undefs.add(export[1:])

  for symbols in symbolses:
    add_back_deps(symbols)

  # If we are only doing forced stdlibs, then we don't know the actual symbols we need,
  # and must assume all of deps_info must be exported. Note that this might cause
  # warnings on exports that do not exist.
  if only_forced:
    for key, value in deps_info.iteritems():
      for dep in value:
        shared.Settings.EXPORTED_FUNCTIONS.append('_' + dep)

  all_needed = set()
  for symbols in symbolses:
    all_needed.update(symbols.undefs)
  for symbols in symbolses:
    all_needed.difference_update(symbols.defs)

  system_libs = [('libcxx',    'a',  create_libcxx,    libcxx_symbols,    ['libcxxabi'], True),
                 ('libcxxabi', 'bc', create_libcxxabi, libcxxabi_symbols, ['libc'],      False),
                 ('gl',        'bc', create_gl,        gl_symbols,        ['libc'],      False)]

  # malloc dependency is force-added, so when using pthreads, it must be force-added
  # as well, since malloc needs to be thread-safe, so it depends on mutexes.
  if shared.Settings.USE_PTHREADS:
    system_libs += [('libc-mt',                     'bc', create_libc,                           libc_symbols,     [],       False),
                    ('pthreads',                    'bc', create_pthreads,                       pthreads_symbols, ['libc'], False),
                    ('dlmalloc_threadsafe',         'bc', create_dlmalloc_multithreaded,         [],               [],       False),
                    ('dlmalloc_threadsafe_tracing', 'bc', create_dlmalloc_multithreaded_tracing, [],               [],       False)]
    force.add('pthreads')
    if shared.Settings.EMSCRIPTEN_TRACING:
      force.add('dlmalloc_threadsafe_tracing')
    else:
      force.add('dlmalloc_threadsafe')
  else:
    system_libs += [('libc', 'bc', create_libc, libc_symbols, [], False)]

    if shared.Settings.EMSCRIPTEN_TRACING:
      system_libs += [('dlmalloc_tracing', 'bc', create_dlmalloc_singlethreaded_tracing, [], [], False)]
      force.add('dlmalloc_tracing')
    else:
      if shared.Settings.SPLIT_MEMORY:
        system_libs += [('dlmalloc_split', 'bc', create_dlmalloc_split, [], [], False)]
        force.add('dlmalloc_split')
      else:
        system_libs += [('dlmalloc', 'bc', create_dlmalloc_singlethreaded, [], [], False)]
        force.add('dlmalloc')

  # Go over libraries to figure out which we must include
  def maybe_noexcept(name):
    if shared.Settings.DISABLE_EXCEPTION_CATCHING:
      name += '_noexcept'
    return name
  ret = []
  has = need = None

  for shortname, suffix, create, library_symbols, deps, can_noexcept in system_libs:
    force_this = force_all or shortname in force
    if can_noexcept: shortname = maybe_noexcept(shortname)
    if force_this:
      suffix = 'bc' # .a files do not always link in all their parts; don't use them when forced
    name = shortname + '.' + suffix

    if not force_this:
      need = set()
      has = set()
      for symbols in symbolses:
        if shared.Settings.VERBOSE: logging.debug('undefs: ' + str(symbols.undefs))
        for library_symbol in library_symbols:
          if library_symbol in symbols.undefs:
            need.add(library_symbol)
          if library_symbol in symbols.defs:
            has.add(library_symbol)
      for haz in has: # remove symbols that are supplied by another of the inputs
        if haz in need:
          need.remove(haz)
      if shared.Settings.VERBOSE: logging.debug('considering %s: we need %s and have %s' % (name, str(need), str(has)))
    if force_this or (len(need) > 0 and not only_forced):
      # We need to build and link the library in
      logging.debug('including %s' % name)
      def do_create():
        ret = create(name)
        return ret
      libfile = shared.Cache.get(name, do_create, extension=suffix)
      ret.append(libfile)
      force = force.union(deps)
  ret.sort(key=lambda x: x.endswith('.a')) # make sure to put .a files at the end.
  return ret

#---------------------------------------------------------------------------
# emscripten-ports library management (https://github.com/emscripten-ports)
#---------------------------------------------------------------------------

import ports

class Ports:
  @staticmethod
  def build_port(src_path, output_path, includes=[], flags=[], exclude_files=[], exclude_dirs=[]):
      srcs = []
      for root, dirs, files in os.walk(src_path, topdown=False):
        if any((excluded in root) for excluded in exclude_dirs):
          continue
        for file in files:
            if (file.endswith('.c') or file.endswith('.cpp')) and not any((excluded in file) for excluded in exclude_files):
                srcs.append(os.path.join(root, file))
      include_commands = ['-I' + src_path ]
      for include in includes:
          include_commands.append('-I' + include)

      commands = []
      objects = []
      for src in srcs:
        obj = src + '.o'
        commands.append([shared.PYTHON, shared.EMCC, src, '-O2', '-o', obj, '-w'] + include_commands + flags)
        objects.append(obj)

      run_commands(commands)
      shared.Building.link(objects, output_path)

  @staticmethod
  def run_commands(commands): # make easily available for port objects
    run_commands(commands)

  @staticmethod
  def get_dir():
    dirname = os.environ.get('EM_PORTS') or os.path.expanduser(os.path.join('~', '.emscripten_ports'))
    shared.safe_ensure_dirs(dirname)
    return dirname

  @staticmethod
  def erase():
    shared.try_delete(Ports.get_dir())

  @staticmethod
  def get_build_dir():
    return shared.Cache.get_path('ports-builds')

  name_cache = set()

  @staticmethod
  def fetch_project(name, url, subdir):
    fullname = os.path.join(Ports.get_dir(), name)

    if name not in Ports.name_cache: # only mention each port once in log
      logging.debug('including port: ' + name)
      logging.debug('    (at ' + fullname + ')')
      Ports.name_cache.add(name)

    class State:
      retrieved = False
      unpacked = False

    def retrieve():
      # if EMCC_LOCAL_PORTS is set, we use a local directory as our ports. This is useful
      # for testing. This env var should be in format
      #     name=dir|tag,name=dir|tag
      # e.g.
      #     sdl2=/home/username/dev/ports/SDL2|SDL2-master
      # so you could run
      #     EMCC_LOCAL_PORTS="sdl2=/home/alon/Dev/ports/SDL2|SDL2-master" ./tests/runner.py browser.test_sdl2_mouse
      # note that tag **must** be the tag in sdl.py, it is where we store to (not where we load from, we just load the local dir)
      local_ports = os.environ.get('EMCC_LOCAL_PORTS')
      if local_ports:
        local_ports = map(lambda pair: pair.split('='), local_ports.split(','))
        for local in local_ports:
          if name == local[0]:
            path, subdir = local[1].split('|')
            logging.warning('grabbing local port: ' + name + ' from ' + path + ', into ' + subdir)
            # zip up the directory, so it looks the same as if we downloaded a zip from the remote server
            z = zipfile.ZipFile(fullname + '.zip', 'w')
            def add_dir(p):
              for f in os.listdir(p):
                full = os.path.join(p, f)
                if os.path.isdir(full):
                  add_dir(full)
                else:
                  if not f.startswith('.'): # ignore hidden files, including .git/ etc.
                    z.write(full, os.path.join(subdir, os.path.relpath(full, path)))
            add_dir(path)
            z.close()
            State.retrieved = True
            return
      # retrieve from remote server
      logging.warning('retrieving port: ' + name + ' from ' + url)
      import urllib2
      f = urllib2.urlopen(url)
      data = f.read()
      open(fullname + '.zip', 'wb').write(data)
      State.retrieved = True

    def check_tag():
      z = zipfile.ZipFile(fullname + '.zip', 'r')
      names = z.namelist()
      if not (names[0].startswith(subdir + '/') or names[0].startswith(subdir + '\\')):
        # current zip file is old, force a retrieve
        return False
      return True

    def unpack():
      logging.warning('unpacking port: ' + name)
      shared.safe_ensure_dirs(fullname)
      z = zipfile.ZipFile(fullname + '.zip', 'r')
      try:
        cwd = os.getcwd()
        os.chdir(fullname)
        z.extractall()
      finally:
        os.chdir(cwd)
      State.unpacked = True

    # main logic

    if not os.path.exists(fullname + '.zip'):
      retrieve()

    if not os.path.exists(fullname):
      unpack()

    if not check_tag():
      logging.warning('local copy of port is not correct, retrieving from remote server')
      shared.try_delete(fullname)
      shared.try_delete(fullname + '.zip')
      retrieve()
      unpack()

    if State.unpacked:
      # we unpacked a new version, clear the build in the cache
      Ports.clear_project_build(name)

  @staticmethod
  def build_project(name, subdir, configure, generated_libs, post_create=None):
    def create():
      logging.warning('building port: ' + name + '...')
      port_build_dir = Ports.get_build_dir()
      shared.safe_ensure_dirs(port_build_dir)
      libs = shared.Building.build_library(name, port_build_dir, None, generated_libs, source_dir=os.path.join(Ports.get_dir(), name, subdir), copy_project=True,
                                           configure=configure, make=['make', '-j' + str(CORES)])
      assert len(libs) == 1
      if post_create: post_create()
      return libs[0]
    return shared.Cache.get(name, create)

  @staticmethod
  def clear_project_build(name):
    shared.try_delete(os.path.join(Ports.get_build_dir(), name))
    shared.try_delete(shared.Cache.get_path(name + '.bc'))

def get_ports(settings):
  ret = []

  ok = False
  try:
    process_dependencies(settings)
    for port in ports.ports:
      ret += port.get(Ports, settings, shared)
    ok = True
  finally:
    if not ok:
      logging.error('a problem occurred when using an emscripten-ports library. try to run    emcc --clear-cache --clear-ports    and then run this command again')

  ret.reverse()
  return ret

def process_dependencies(settings):
  for port in reversed(ports.ports):
    if hasattr(port, "process_dependencies"):
      port.process_dependencies(settings)

def process_args(args, settings):
  process_dependencies(settings)
  for port in ports.ports:
    args = port.process_args(Ports, args, settings, shared)
  return args

def show_ports():
  print 'Available ports:'
  for port in ports.ports:
    print '   ', port.show()