text: """SCons.Tool.applelink
  
  Tool-specific initialization for Apple's gnu-like linker.
  
  There normally shouldn't be any need to import this module directly.
  It will usually be imported through the generic SCons.Tool.Tool()
  selection method.
  
  """
  
  #
  # Copyright (c) 2001 - 2019 The SCons Foundation
  #
  # Permission is hereby granted, free of charge, to any person obtaining
  # a copy of this software and associated documentation files (the
  # "Software"), to deal in the Software without restriction, including
  # without limitation the rights to use, copy, modify, merge, publish,
  # distribute, sublicense, and/or sell copies of the Software, and to
  # permit persons to whom the Software is furnished to do so, subject to
  # the following conditions:
  #
  # The above copyright notice and this permission notice shall be included
  # in all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
  # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
  # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  #
  
  __revision__ = "src/engine/SCons/Tool/applelink.py 72ae09dc35ac2626f8ff711d8c4b30b6138e08e3 2019-08-08 14:50:06 bdeegan"
  
  import SCons.Util
  
  # Even though the Mac is based on the GNU toolchain, it doesn't understand
  # the -rpath option, so we use the "link" tool instead of "gnulink".
  from . import link
  
  
  class AppleLinkInvalidCurrentVersionException(Exception):
      pass
  
  class AppleLinkInvalidCompatibilityVersionException(Exception):
      pass
  
  
  def _applelib_versioned_lib_suffix(env, suffix, version):
      """For suffix='.dylib' and version='0.1.2' it returns '.0.1.2.dylib'"""
      Verbose = False
      if Verbose:
          print("_applelib_versioned_lib_suffix: suffix={!r}".format(suffix))
          print("_applelib_versioned_lib_suffix: version={!r}".format(version))
      if version not in suffix:
          suffix = "." + version + suffix
      if Verbose:
          print("_applelib_versioned_lib_suffix: return suffix={!r}".format(suffix))
      return suffix
  
  
  def _applelib_versioned_lib_soname(env, libnode, version, prefix, suffix, name_func):
      """For libnode='/optional/dir/libfoo.X.Y.Z.dylib' it returns 'libfoo.X.dylib'"""
      Verbose = False
      if Verbose:
          print("_applelib_versioned_lib_soname: version={!r}".format(version))
      name = name_func(env, libnode, version, prefix, suffix)
      if Verbose:
          print("_applelib_versioned_lib_soname: name={!r}".format(name))
      major = version.split('.')[0]
      (libname,_suffix) = name.split('.')
      soname = '.'.join([libname, major, _suffix])
      if Verbose:
          print("_applelib_versioned_lib_soname: soname={!r}".format(soname))
      return soname
  
  def _applelib_versioned_shlib_soname(env, libnode, version, prefix, suffix):
      return _applelib_versioned_lib_soname(env, libnode, version, prefix, suffix, link._versioned_shlib_name)
  
  
  # User programmatically describes how SHLIBVERSION maps to values for compat/current.
  _applelib_max_version_values = (65535, 255, 255)
  def _applelib_check_valid_version(version_string):
      """
      Check that the version # is valid.
      X[.Y[.Z]]
      where X 0-65535
      where Y either not specified or 0-255
      where Z either not specified or 0-255
      :param version_string:
      :return:
      """
      parts = version_string.split('.')
      if len(parts) > 3:
          return False, "Version string has too many periods [%s]"%version_string
      if len(parts) <= 0:
          return False, "Version string unspecified [%s]"%version_string
  
      for (i, p) in enumerate(parts):
          try:
              p_i = int(p)
          except ValueError:
              return False, "Version component %s (from %s) is not a number"%(p, version_string)
          if p_i < 0 or p_i > _applelib_max_version_values[i]:
              return False, "Version component %s (from %s) is not valid value should be between 0 and %d"%(p, version_string, _applelib_max_version_values[i])
  
      return True, ""
  
  
  def _applelib_currentVersionFromSoVersion(source, target, env, for_signature):
      """
      A generator function to create the -Wl,-current_version flag if needed.
      If env['APPLELINK_NO_CURRENT_VERSION'] contains a true value no flag will be generated
      Otherwise if APPLELINK_CURRENT_VERSION is not specified, env['SHLIBVERSION']
      will be used.
  
      :param source:
      :param target:
      :param env:
      :param for_signature:
      :return: A string providing the flag to specify the current_version of the shared library
      """
      if env.get('APPLELINK_NO_CURRENT_VERSION', False):
          return ""
      elif env.get('APPLELINK_CURRENT_VERSION', False):
          version_string = env['APPLELINK_CURRENT_VERSION']
      elif env.get('SHLIBVERSION', False):
          version_string = env['SHLIBVERSION']
      else:
          return ""
  
      version_string = ".".join(version_string.split('.')[:3])
  
      valid, reason = _applelib_check_valid_version(version_string)
      if not valid:
          raise AppleLinkInvalidCurrentVersionException(reason)
  
      return "-Wl,-current_version,%s" % version_string
  
  
  def _applelib_compatVersionFromSoVersion(source, target, env, for_signature):
      """
      A generator function to create the -Wl,-compatibility_version flag if needed.
      If env['APPLELINK_NO_COMPATIBILITY_VERSION'] contains a true value no flag will be generated
      Otherwise if APPLELINK_COMPATIBILITY_VERSION is not specified
      the first two parts of env['SHLIBVERSION'] will be used with a .0 appended.
  
      :param source:
      :param target:
      :param env:
      :param for_signature:
      :return: A string providing the flag to specify the compatibility_version of the shared library
      """
      if env.get('APPLELINK_NO_COMPATIBILITY_VERSION', False):
          return ""
      elif env.get('APPLELINK_COMPATIBILITY_VERSION', False):
          version_string = env['APPLELINK_COMPATIBILITY_VERSION']
      elif env.get('SHLIBVERSION', False):
          version_string = ".".join(env['SHLIBVERSION'].split('.')[:2] + ['0'])
      else:
          return ""
  
      if version_string is None:
          return ""
  
      valid, reason = _applelib_check_valid_version(version_string)
      if not valid:
          raise AppleLinkInvalidCompatibilityVersionException(reason)
  
      return "-Wl,-compatibility_version,%s" % version_string
  
  
  def generate(env):
      """Add Builders and construction variables for applelink to an
      Environment."""
      link.generate(env)
  
      env['FRAMEWORKPATHPREFIX'] = '-F'
      env['_FRAMEWORKPATH'] = '${_concat(FRAMEWORKPATHPREFIX, FRAMEWORKPATH, "", __env__, RDirs)}'
  
      env['_FRAMEWORKS'] = '${_concat("-framework ", FRAMEWORKS, "", __env__)}'
      env['LINKCOM'] = env['LINKCOM'] + ' $_FRAMEWORKPATH $_FRAMEWORKS $FRAMEWORKSFLAGS'
      env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -dynamiclib')
      env['SHLINKCOM'] = env['SHLINKCOM'] + ' $_FRAMEWORKPATH $_FRAMEWORKS $FRAMEWORKSFLAGS'
  
  
      # see: http://docstore.mik.ua/orelly/unix3/mac/ch05_04.htm  for proper naming
      link._setup_versioned_lib_variables(env, tool = 'applelink')#, use_soname = use_soname)
      env['LINKCALLBACKS'] = link._versioned_lib_callbacks()
      env['LINKCALLBACKS']['VersionedShLibSuffix'] = _applelib_versioned_lib_suffix
      env['LINKCALLBACKS']['VersionedShLibSoname'] = _applelib_versioned_shlib_soname
  
      env['_APPLELINK_CURRENT_VERSION'] = _applelib_currentVersionFromSoVersion
      env['_APPLELINK_COMPATIBILITY_VERSION'] = _applelib_compatVersionFromSoVersion
      env['_SHLIBVERSIONFLAGS'] = '$_APPLELINK_CURRENT_VERSION $_APPLELINK_COMPATIBILITY_VERSION '
      env['_LDMODULEVERSIONFLAGS'] = '$_APPLELINK_CURRENT_VERSION $_APPLELINK_COMPATIBILITY_VERSION '
  
      # override the default for loadable modules, which are different
      # on OS X than dynamic shared libs.  echoing what XCode does for
      # pre/suffixes:
      env['LDMODULEPREFIX'] = '' 
      env['LDMODULESUFFIX'] = '' 
      env['LDMODULEFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -bundle')
      env['LDMODULECOM'] = '$LDMODULE -o ${TARGET} $LDMODULEFLAGS $SOURCES $_LIBDIRFLAGS $_LIBFLAGS $_FRAMEWORKPATH $_FRAMEWORKS $FRAMEWORKSFLAGS'
  
      env['__SHLIBVERSIONFLAGS'] = '${__libversionflags(__env__,"SHLIBVERSION","_SHLIBVERSIONFLAGS")}'
  
  
  
  def exists(env):
      return env['PLATFORM'] == 'darwin'
  
  # Local Variables:
  # tab-width:4
  # indent-tabs-mode:nil
  # End:
  # vim: set expandtab tabstop=4 shiftwidth=4:
  