text: """SCons.Action
  
  This encapsulates information about executing any sort of action that
  can build one or more target Nodes (typically files) from one or more
  source Nodes (also typically files) given a specific Environment.
  
  The base class here is ActionBase.  The base class supplies just a few
  OO utility methods and some generic methods for displaying information
  about an Action in response to the various commands that control printing.
  
  A second-level base class is _ActionAction.  This extends ActionBase
  by providing the methods that can be used to show and perform an
  action.  True Action objects will subclass _ActionAction; Action
  factory class objects will subclass ActionBase.
  
  The heavy lifting is handled by subclasses for the different types of
  actions we might execute:
  
      CommandAction
      CommandGeneratorAction
      FunctionAction
      ListAction
  
  The subclasses supply the following public interface methods used by
  other modules:
  
      __call__()
          THE public interface, "calling" an Action object executes the
          command or Python function.  This also takes care of printing
          a pre-substitution command for debugging purposes.
  
      get_contents()
          Fetches the "contents" of an Action for signature calculation
          plus the varlist.  This is what gets MD5 checksummed to decide
          if a target needs to be rebuilt because its action changed.
  
      genstring()
          Returns a string representation of the Action *without*
          command substitution, but allows a CommandGeneratorAction to
          generate the right action based on the specified target,
          source and env.  This is used by the Signature subsystem
          (through the Executor) to obtain an (imprecise) representation
          of the Action operation for informative purposes.
  
  
  Subclasses also supply the following methods for internal use within
  this module:
  
      __str__()
          Returns a string approximation of the Action; no variable
          substitution is performed.
  
      execute()
          The internal method that really, truly, actually handles the
          execution of a command or Python function.  This is used so
          that the __call__() methods can take care of displaying any
          pre-substitution representations, and *then* execute an action
          without worrying about the specific Actions involved.
  
      get_presig()
          Fetches the "contents" of a subclass for signature calculation.
          The varlist is added to this to produce the Action's contents.
  
      strfunction()
          Returns a substituted string representation of the Action.
          This is used by the _ActionAction.show() command to display the
          command/function that will be executed to generate the target(s).
  
  There is a related independent ActionCaller class that looks like a
  regular Action, and which serves as a wrapper for arbitrary functions
  that we want to let the user specify the arguments to now, but actually
  execute later (when an out-of-date check determines that it's needed to
  be executed, for example).  Objects of this class are returned by an
  ActionFactory class that provides a __call__() method as a convenient
  way for wrapping up the functions.
  
  """
  
  # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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/Action.py 5023 2010/06/14 22:05:46 scons"
  
  import SCons.compat
  
  import dis
  import os
  # compat layer imports "cPickle" for us if it's available.
  import pickle
  import re
  import sys
  import subprocess
  
  from SCons.Debug import logInstanceCreation
  import SCons.Errors
  import SCons.Executor
  import SCons.Util
  import SCons.Subst
  
  # we use these a lot, so try to optimize them
  is_String = SCons.Util.is_String
  is_List = SCons.Util.is_List
  
  class _null(object):
      pass
  
  print_actions = 1
  execute_actions = 1
  print_actions_presub = 0
  
  def rfile(n):
      try:
          return n.rfile()
      except AttributeError:
          return n
  
  def default_exitstatfunc(s):
      return s
  
  try:
      SET_LINENO = dis.SET_LINENO
      HAVE_ARGUMENT = dis.HAVE_ARGUMENT
  except AttributeError:
      remove_set_lineno_codes = lambda x: x
  else:
      def remove_set_lineno_codes(code):
          result = []
          n = len(code)
          i = 0
          while i < n:
              c = code[i]
              op = ord(c)
              if op >= HAVE_ARGUMENT:
                  if op != SET_LINENO:
                      result.append(code[i:i+3])
                  i = i+3
              else:
                  result.append(c)
                  i = i+1
          return ''.join(result)
  
  strip_quotes = re.compile('^[\'"](.*)[\'"]$')
  
  
  def _callable_contents(obj):
      """Return the signature contents of a callable Python object.
      """
      try:
          # Test if obj is a method.
          return _function_contents(obj.im_func)
  
      except AttributeError:
          try:
              # Test if obj is a callable object.
              return _function_contents(obj.__call__.im_func)
  
          except AttributeError:
              try:
                  # Test if obj is a code object.
                  return _code_contents(obj)
  
              except AttributeError:
                      # Test if obj is a function object.
                      return _function_contents(obj)
  
  
  def _object_contents(obj):
      """Return the signature contents of any Python object.
  
      We have to handle the case where object contains a code object
      since it can be pickled directly.
      """
      try:
          # Test if obj is a method.
          return _function_contents(obj.im_func)
  
      except AttributeError:
          try:
              # Test if obj is a callable object.
              return _function_contents(obj.__call__.im_func)
  
          except AttributeError:
              try:
                  # Test if obj is a code object.
                  return _code_contents(obj)
  
              except AttributeError:
                  try:
                      # Test if obj is a function object.
                      return _function_contents(obj)
  
                  except AttributeError:
                      # Should be a pickable Python object.
                      try:
                          return pickle.dumps(obj)
                      except (pickle.PicklingError, TypeError):
                          # This is weird, but it seems that nested classes
                          # are unpickable. The Python docs say it should
                          # always be a PicklingError, but some Python
                          # versions seem to return TypeError.  Just do
                          # the best we can.
                          return str(obj)
  
  
  def _code_contents(code):
      """Return the signature contents of a code object.
  
      By providing direct access to the code object of the
      function, Python makes this extremely easy.  Hooray!
  
      Unfortunately, older versions of Python include line
      number indications in the compiled byte code.  Boo!
      So we remove the line number byte codes to prevent
      recompilations from moving a Python function.
      """
  
      contents = []
  
      # The code contents depends on the number of local variables
      # but not their actual names.
      contents.append("%s,%s" % (code.co_argcount, len(code.co_varnames)))
      try:
          contents.append(",%s,%s" % (len(code.co_cellvars), len(code.co_freevars)))
      except AttributeError:
          # Older versions of Python do not support closures.
          contents.append(",0,0")
  
      # The code contents depends on any constants accessed by the
      # function. Note that we have to call _object_contents on each
      # constants because the code object of nested functions can
      # show-up among the constants.
      #
      # Note that we also always ignore the first entry of co_consts
      # which contains the function doc string. We assume that the
      # function does not access its doc string.
      contents.append(',(' + ','.join(map(_object_contents,code.co_consts[1:])) + ')')
  
      # The code contents depends on the variable names used to
      # accessed global variable, as changing the variable name changes
      # the variable actually accessed and therefore changes the
      # function result.
      contents.append(',(' + ','.join(map(_object_contents,code.co_names)) + ')')
  
  
      # The code contents depends on its actual code!!!
      contents.append(',(' + str(remove_set_lineno_codes(code.co_code)) + ')')
  
      return ''.join(contents)
  
  
  def _function_contents(func):
      """Return the signature contents of a function."""
  
      contents = [_code_contents(func.func_code)]
  
      # The function contents depends on the value of defaults arguments
      if func.func_defaults:
          contents.append(',(' + ','.join(map(_object_contents,func.func_defaults)) + ')')
      else:
          contents.append(',()')
  
      # The function contents depends on the closure captured cell values.
      try:
          closure = func.func_closure or []
      except AttributeError:
          # Older versions of Python do not support closures.
          closure = []
  
      #xxx = [_object_contents(x.cell_contents) for x in closure]
      try:
          xxx = [_object_contents(x.cell_contents) for x in closure]
      except AttributeError:
          xxx = []
      contents.append(',(' + ','.join(xxx) + ')')
  
      return ''.join(contents)
  
  
  def _actionAppend(act1, act2):
      # This function knows how to slap two actions together.
      # Mainly, it handles ListActions by concatenating into
      # a single ListAction.
      a1 = Action(act1)
      a2 = Action(act2)
      if a1 is None or a2 is None:
          raise TypeError("Cannot append %s to %s" % (type(act1), type(act2)))
      if isinstance(a1, ListAction):
          if isinstance(a2, ListAction):
              return ListAction(a1.list + a2.list)
          else:
              return ListAction(a1.list + [ a2 ])
      else:
          if isinstance(a2, ListAction):
              return ListAction([ a1 ] + a2.list)
          else:
              return ListAction([ a1, a2 ])
  
  def _do_create_keywords(args, kw):
      """This converts any arguments after the action argument into
      their equivalent keywords and adds them to the kw argument.
      """
      v = kw.get('varlist', ())
      # prevent varlist="FOO" from being interpreted as ['F', 'O', 'O']
      if is_String(v): v = (v,)
      kw['varlist'] = tuple(v)
      if args:
          # turn positional args into equivalent keywords
          cmdstrfunc = args[0]
          if cmdstrfunc is None or is_String(cmdstrfunc):
              kw['cmdstr'] = cmdstrfunc
          elif callable(cmdstrfunc):
              kw['strfunction'] = cmdstrfunc
          else:
              raise SCons.Errors.UserError(
                  'Invalid command display variable type. '
                  'You must either pass a string or a callback which '
                  'accepts (target, source, env) as parameters.')
          if len(args) > 1:
              kw['varlist'] = args[1:] + kw['varlist']
      if kw.get('strfunction', _null) is not _null \
                        and kw.get('cmdstr', _null) is not _null:
          raise SCons.Errors.UserError(
              'Cannot have both strfunction and cmdstr args to Action()')
  
  def _do_create_action(act, kw):
      """This is the actual "implementation" for the
      Action factory method, below.  This handles the
      fact that passing lists to Action() itself has
      different semantics than passing lists as elements
      of lists.
  
      The former will create a ListAction, the latter
      will create a CommandAction by converting the inner
      list elements to strings."""
  
      if isinstance(act, ActionBase):
          return act
  
      if is_List(act):
          return CommandAction(act, **kw)
  
      if callable(act):
          try:
              gen = kw['generator']
              del kw['generator']
          except KeyError:
              gen = 0
          if gen:
              action_type = CommandGeneratorAction
          else:
              action_type = FunctionAction
          return action_type(act, kw)
  
      if is_String(act):
          var=SCons.Util.get_environment_var(act)
          if var:
              # This looks like a string that is purely an Environment
              # variable reference, like "$FOO" or "${FOO}".  We do
              # something special here...we lazily evaluate the contents
              # of that Environment variable, so a user could put something
              # like a function or a CommandGenerator in that variable
              # instead of a string.
              return LazyAction(var, kw)
          commands = str(act).split('\n')
          if len(commands) == 1:
              return CommandAction(commands[0], **kw)
          # The list of string commands may include a LazyAction, so we
          # reprocess them via _do_create_list_action.
          return _do_create_list_action(commands, kw)
      return None
  
  def _do_create_list_action(act, kw):
      """A factory for list actions.  Convert the input list into Actions
      and then wrap them in a ListAction."""
      acts = []
      for a in act:
          aa = _do_create_action(a, kw)
          if aa is not None: acts.append(aa)
      if not acts:
          return ListAction([])
      elif len(acts) == 1:
          return acts[0]
      else:
          return ListAction(acts)
  
  def Action(act, *args, **kw):
      """A factory for action objects."""
      # Really simple: the _do_create_* routines do the heavy lifting.
      _do_create_keywords(args, kw)
      if is_List(act):
          return _do_create_list_action(act, kw)
      return _do_create_action(act, kw)
  
  class ActionBase(object):
      """Base class for all types of action objects that can be held by
      other objects (Builders, Executors, etc.)  This provides the
      common methods for manipulating and combining those actions."""
  
      def __cmp__(self, other):
          return cmp(self.__dict__, other)
  
      def no_batch_key(self, env, target, source):
          return None
  
      batch_key = no_batch_key
  
      def genstring(self, target, source, env):
          return str(self)
  
      def get_contents(self, target, source, env):
          result = [ self.get_presig(target, source, env) ]
          # This should never happen, as the Action() factory should wrap
          # the varlist, but just in case an action is created directly,
          # we duplicate this check here.
          vl = self.get_varlist(target, source, env)
          if is_String(vl): vl = (vl,)
          for v in vl:
              result.append(env.subst('${'+v+'}'))
          return ''.join(result)
  
      def __add__(self, other):
          return _actionAppend(self, other)
  
      def __radd__(self, other):
          return _actionAppend(other, self)
  
      def presub_lines(self, env):
          # CommandGeneratorAction needs a real environment
          # in order to return the proper string here, since
          # it may call LazyAction, which looks up a key
          # in that env.  So we temporarily remember the env here,
          # and CommandGeneratorAction will use this env
          # when it calls its _generate method.
          self.presub_env = env
          lines = str(self).split('\n')
          self.presub_env = None      # don't need this any more
          return lines
  
      def get_varlist(self, target, source, env, executor=None):
          return self.varlist
  
      def get_targets(self, env, executor):
          """
          Returns the type of targets ($TARGETS, $CHANGED_TARGETS) used
          by this action.
          """
          return self.targets
  
  class _ActionAction(ActionBase):
      """Base class for actions that create output objects."""
      def __init__(self, cmdstr=_null, strfunction=_null, varlist=(),
                         presub=_null, chdir=None, exitstatfunc=None,
                         batch_key=None, targets='$TARGETS',
                   **kw):
          self.cmdstr = cmdstr
          if strfunction is not _null:
              if strfunction is None:
                  self.cmdstr = None
              else:
                  self.strfunction = strfunction
          self.varlist = varlist
          self.presub = presub
          self.chdir = chdir
          if not exitstatfunc:
              exitstatfunc = default_exitstatfunc
          self.exitstatfunc = exitstatfunc
  
          self.targets = targets
  
          if batch_key:
              if not callable(batch_key):
                  # They have set batch_key, but not to their own
                  # callable.  The default behavior here will batch
                  # *all* targets+sources using this action, separated
                  # for each construction environment.
                  def default_batch_key(self, env, target, source):
                      return (id(self), id(env))
                  batch_key = default_batch_key
              SCons.Util.AddMethod(self, batch_key, 'batch_key')
  
      def print_cmd_line(self, s, target, source, env):
          sys.stdout.write(s + u"\n")
  
      def __call__(self, target, source, env,
                                 exitstatfunc=_null,
                                 presub=_null,
                                 show=_null,
                                 execute=_null,
                                 chdir=_null,
                                 executor=None):
          if not is_List(target):
              target = [target]
          if not is_List(source):
              source = [source]
  
          if presub is _null:
              presub = self.presub
              if presub is _null:
                  presub = print_actions_presub
          if exitstatfunc is _null: exitstatfunc = self.exitstatfunc
          if show is _null:  show = print_actions
          if execute is _null:  execute = execute_actions
          if chdir is _null: chdir = self.chdir
          save_cwd = None
          if chdir:
              save_cwd = os.getcwd()
              try:
                  chdir = str(chdir.abspath)
              except AttributeError:
                  if not is_String(chdir):
                      if executor:
                          chdir = str(executor.batches[0].targets[0].dir)
                      else:
                          chdir = str(target[0].dir)
          if presub:
              if executor:
                  target = executor.get_all_targets()
                  source = executor.get_all_sources()
              t = ' and '.join(map(str, target))
              l = '\n  '.join(self.presub_lines(env))
              out = u"Building %s with action:\n  %s\n" % (t, l)
              sys.stdout.write(out)
          cmd = None
          if show and self.strfunction:
              if executor:
                  target = executor.get_all_targets()
                  source = executor.get_all_sources()
              try:
                  cmd = self.strfunction(target, source, env, executor)
              except TypeError:
                  cmd = self.strfunction(target, source, env)
              if cmd:
                  if chdir:
                      cmd = ('os.chdir(%s)\n' % repr(chdir)) + cmd
                  try:
                      get = env.get
                  except AttributeError:
                      print_func = self.print_cmd_line
                  else:
                      print_func = get('PRINT_CMD_LINE_FUNC')
                      if not print_func:
                          print_func = self.print_cmd_line
                  print_func(cmd, target, source, env)
          stat = 0
          if execute:
              if chdir:
                  os.chdir(chdir)
              try:
                  stat = self.execute(target, source, env, executor=executor)
                  if isinstance(stat, SCons.Errors.BuildError):
                      s = exitstatfunc(stat.status)
                      if s:
                          stat.status = s
                      else:
                          stat = s
                  else:
                      stat = exitstatfunc(stat)
              finally:
                  if save_cwd:
                      os.chdir(save_cwd)
          if cmd and save_cwd:
              print_func('os.chdir(%s)' % repr(save_cwd), target, source, env)
  
          return stat
  
  
  def _string_from_cmd_list(cmd_list):
      """Takes a list of command line arguments and returns a pretty
      representation for printing."""
      cl = []
      for arg in map(str, cmd_list):
          if ' ' in arg or '\t' in arg:
              arg = '"' + arg + '"'
          cl.append(arg)
      return ' '.join(cl)
  
  # A fiddlin' little function that has an 'import SCons.Environment' which
  # can't be moved to the top level without creating an import loop.  Since
  # this import creates a local variable named 'SCons', it blocks access to
  # the global variable, so we move it here to prevent complaints about local
  # variables being used uninitialized.
  default_ENV = None
  def get_default_ENV(env):
      global default_ENV
      try:
          return env['ENV']
      except KeyError:
          if not default_ENV:
              import SCons.Environment
              # This is a hideously expensive way to get a default shell
              # environment.  What it really should do is run the platform
              # setup to get the default ENV.  Fortunately, it's incredibly
              # rare for an Environment not to have a shell environment, so
              # we're not going to worry about it overmuch.
              default_ENV = SCons.Environment.Environment()['ENV']
          return default_ENV
  
  # This function is still in draft mode.  We're going to need something like
  # it in the long run as more and more places use subprocess, but I'm sure
  # it'll have to be tweaked to get the full desired functionality.
  # one special arg (so far?), 'error', to tell what to do with exceptions.
  def _subproc(scons_env, cmd, error = 'ignore', **kw):
      """Do common setup for a subprocess.Popen() call"""
      # allow std{in,out,err} to be "'devnull'"
      io = kw.get('stdin')
      if is_String(io) and io == 'devnull':
          kw['stdin'] = open(os.devnull)
      io = kw.get('stdout')
      if is_String(io) and io == 'devnull':
          kw['stdout'] = open(os.devnull, 'w')
      io = kw.get('stderr')
      if is_String(io) and io == 'devnull':
          kw['stderr'] = open(os.devnull, 'w')
  
      # Figure out what shell environment to use
      ENV = kw.get('env', None)
      if ENV is None: ENV = get_default_ENV(scons_env)
  
      # Ensure that the ENV values are all strings:
      new_env = {}
      for key, value in ENV.items():
          if is_List(value):
              # If the value is a list, then we assume it is a path list,
              # because that's a pretty common list-like value to stick
              # in an environment variable:
              value = SCons.Util.flatten_sequence(value)
              new_env[key] = os.pathsep.join(map(str, value))
          else:
              # It's either a string or something else.  If it's a string,
              # we still want to call str() because it might be a *Unicode*
              # string, which makes subprocess.Popen() gag.  If it isn't a
              # string or a list, then we just coerce it to a string, which
              # is the proper way to handle Dir and File instances and will
              # produce something reasonable for just about everything else:
              new_env[key] = str(value)
      kw['env'] = new_env
  
      try:
          #FUTURE return subprocess.Popen(cmd, **kw)
          return subprocess.Popen(cmd, **kw)
      except EnvironmentError, e:
          if error == 'raise': raise
          # return a dummy Popen instance that only returns error
          class dummyPopen(object):
              def __init__(self, e): self.exception = e
              def communicate(self): return ('','')
              def wait(self): return -self.exception.errno
              stdin = None
              class f(object):
                  def read(self): return ''
                  def readline(self): return ''
              stdout = stderr = f()
          return dummyPopen(e)
  
  class CommandAction(_ActionAction):
      """Class for command-execution actions."""
      def __init__(self, cmd, **kw):
          # Cmd can actually be a list or a single item; if it's a
          # single item it should be the command string to execute; if a
          # list then it should be the words of the command string to
          # execute.  Only a single command should be executed by this
          # object; lists of commands should be handled by embedding
          # these objects in a ListAction object (which the Action()
          # factory above does).  cmd will be passed to
          # Environment.subst_list() for substituting environment
          # variables.
          if __debug__: logInstanceCreation(self, 'Action.CommandAction')
  
          _ActionAction.__init__(self, **kw)
          if is_List(cmd):
              if list(filter(is_List, cmd)):
                  raise TypeError("CommandAction should be given only " \
                        "a single command")
          self.cmd_list = cmd
  
      def __str__(self):
          if is_List(self.cmd_list):
              return ' '.join(map(str, self.cmd_list))
          return str(self.cmd_list)
  
      def process(self, target, source, env, executor=None):
          if executor:
              result = env.subst_list(self.cmd_list, 0, executor=executor)
          else:
              result = env.subst_list(self.cmd_list, 0, target, source)
          silent = None
          ignore = None
          while True:
              try: c = result[0][0][0]
              except IndexError: c = None
              if c == '@': silent = 1
              elif c == '-': ignore = 1
              else: break
              result[0][0] = result[0][0][1:]
          try:
              if not result[0][0]:
                  result[0] = result[0][1:]
          except IndexError:
              pass
          return result, ignore, silent
  
      def strfunction(self, target, source, env, executor=None):
          if self.cmdstr is None:
              return None
          if self.cmdstr is not _null:
              from SCons.Subst import SUBST_RAW
              if executor:
                  c = env.subst(self.cmdstr, SUBST_RAW, executor=executor)
              else:
                  c = env.subst(self.cmdstr, SUBST_RAW, target, source)
              if c:
                  return c
          cmd_list, ignore, silent = self.process(target, source, env, executor)
          if silent:
              return ''
          return _string_from_cmd_list(cmd_list[0])
  
      def execute(self, target, source, env, executor=None):
          """Execute a command action.
  
          This will handle lists of commands as well as individual commands,
          because construction variable substitution may turn a single
          "command" into a list.  This means that this class can actually
          handle lists of commands, even though that's not how we use it
          externally.
          """
          escape_list = SCons.Subst.escape_list
          flatten_sequence = SCons.Util.flatten_sequence
  
          try:
              shell = env['SHELL']
          except KeyError:
              raise SCons.Errors.UserError('Missing SHELL construction variable.')
  
          try:
              spawn = env['SPAWN']
          except KeyError:
              raise SCons.Errors.UserError('Missing SPAWN construction variable.')
          else:
              if is_String(spawn):
                  spawn = env.subst(spawn, raw=1, conv=lambda x: x)
  
          escape = env.get('ESCAPE', lambda x: x)
  
          ENV = get_default_ENV(env)
  
          # Ensure that the ENV values are all strings:
          for key, value in ENV.items():
              if not is_String(value):
                  if is_List(value):
                      # If the value is a list, then we assume it is a
                      # path list, because that's a pretty common list-like
                      # value to stick in an environment variable:
                      value = flatten_sequence(value)
                      ENV[key] = os.pathsep.join(map(str, value))
                  else:
                      # If it isn't a string or a list, then we just coerce
                      # it to a string, which is the proper way to handle
                      # Dir and File instances and will produce something
                      # reasonable for just about everything else:
                      ENV[key] = str(value)
  
          if executor:
              target = executor.get_all_targets()
              source = executor.get_all_sources()
          cmd_list, ignore, silent = self.process(target, list(map(rfile, source)), env, executor)
  
          # Use len() to filter out any "command" that's zero-length.
          for cmd_line in filter(len, cmd_list):
              # Escape the command line for the interpreter we are using.
              cmd_line = escape_list(cmd_line, escape)
              result = spawn(shell, escape, cmd_line[0], cmd_line, ENV)
              if not ignore and result:
                  msg = "Error %s" % result
                  return SCons.Errors.BuildError(errstr=msg,
                                                 status=result,
                                                 action=self,
                                                 command=cmd_line)
          return 0
  
      def get_presig(self, target, source, env, executor=None):
          """Return the signature contents of this action's command line.
  
          This strips $(-$) and everything in between the string,
          since those parts don't affect signatures.
          """
          from SCons.Subst import SUBST_SIG
          cmd = self.cmd_list
          if is_List(cmd):
              cmd = ' '.join(map(str, cmd))
          else:
              cmd = str(cmd)
          if executor:
              return env.subst_target_source(cmd, SUBST_SIG, executor=executor)
          else:
              return env.subst_target_source(cmd, SUBST_SIG, target, source)
  
      def get_implicit_deps(self, target, source, env, executor=None):
          icd = env.get('IMPLICIT_COMMAND_DEPENDENCIES', True)
          if is_String(icd) and icd[:1] == '$':
              icd = env.subst(icd)
          if not icd or icd in ('0', 'None'):
              return []
          from SCons.Subst import SUBST_SIG
          if executor:
              cmd_list = env.subst_list(self.cmd_list, SUBST_SIG, executor=executor)
          else:
              cmd_list = env.subst_list(self.cmd_list, SUBST_SIG, target, source)
          res = []
          for cmd_line in cmd_list:
              if cmd_line:
                  d = str(cmd_line[0])
                  m = strip_quotes.match(d)
                  if m:
                      d = m.group(1)
                  d = env.WhereIs(d)
                  if d:
                      res.append(env.fs.File(d))
          return res
  
  class CommandGeneratorAction(ActionBase):
      """Class for command-generator actions."""
      def __init__(self, generator, kw):
          if __debug__: logInstanceCreation(self, 'Action.CommandGeneratorAction')
          self.generator = generator
          self.gen_kw = kw
          self.varlist = kw.get('varlist', ())
          self.targets = kw.get('targets', '$TARGETS')
  
      def _generate(self, target, source, env, for_signature, executor=None):
          # ensure that target is a list, to make it easier to write
          # generator functions:
          if not is_List(target):
              target = [target]
  
          if executor:
              target = executor.get_all_targets()
              source = executor.get_all_sources()
          ret = self.generator(target=target,
                               source=source,
                               env=env,
                               for_signature=for_signature)
          gen_cmd = Action(ret, **self.gen_kw)
          if not gen_cmd:
              raise SCons.Errors.UserError("Object returned from command generator: %s cannot be used to create an Action." % repr(ret))
          return gen_cmd
  
      def __str__(self):
          try:
              env = self.presub_env
          except AttributeError:
              env = None
          if env is None:
              env = SCons.Defaults.DefaultEnvironment()
          act = self._generate([], [], env, 1)
          return str(act)
  
      def batch_key(self, env, target, source):
          return self._generate(target, source, env, 1).batch_key(env, target, source)
  
      def genstring(self, target, source, env, executor=None):
          return self._generate(target, source, env, 1, executor).genstring(target, source, env)
  
      def __call__(self, target, source, env, exitstatfunc=_null, presub=_null,
                   show=_null, execute=_null, chdir=_null, executor=None):
          act = self._generate(target, source, env, 0, executor)
          if act is None:
              raise UserError("While building `%s': "
                              "Cannot deduce file extension from source files: %s"
                  % (repr(list(map(str, target))), repr(list(map(str, source)))))
          return act(target, source, env, exitstatfunc, presub,
                     show, execute, chdir, executor)
  
      def get_presig(self, target, source, env, executor=None):
          """Return the signature contents of this action's command line.
  
          This strips $(-$) and everything in between the string,
          since those parts don't affect signatures.
          """
          return self._generate(target, source, env, 1, executor).get_presig(target, source, env)
  
      def get_implicit_deps(self, target, source, env, executor=None):
          return self._generate(target, source, env, 1, executor).get_implicit_deps(target, source, env)
  
      def get_varlist(self, target, source, env, executor=None):
          return self._generate(target, source, env, 1, executor).get_varlist(target, source, env, executor)
  
      def get_targets(self, env, executor):
          return self._generate(None, None, env, 1, executor).get_targets(env, executor)
  
  
  
  # A LazyAction is a kind of hybrid generator and command action for
  # strings of the form "$VAR".  These strings normally expand to other
  # strings (think "$CCCOM" to "$CC -c -o $TARGET $SOURCE"), but we also
  # want to be able to replace them with functions in the construction
  # environment.  Consequently, we want lazy evaluation and creation of
  # an Action in the case of the function, but that's overkill in the more
  # normal case of expansion to other strings.
  #
  # So we do this with a subclass that's both a generator *and*
  # a command action.  The overridden methods all do a quick check
  # of the construction variable, and if it's a string we just call
  # the corresponding CommandAction method to do the heavy lifting.
  # If not, then we call the same-named CommandGeneratorAction method.
  # The CommandGeneratorAction methods work by using the overridden
  # _generate() method, that is, our own way of handling "generation" of
  # an action based on what's in the construction variable.
  
  class LazyAction(CommandGeneratorAction, CommandAction):
  
      def __init__(self, var, kw):
          if __debug__: logInstanceCreation(self, 'Action.LazyAction')
          #FUTURE CommandAction.__init__(self, '${'+var+'}', **kw)
          CommandAction.__init__(self, '${'+var+'}', **kw)
          self.var = SCons.Util.to_String(var)
          self.gen_kw = kw
  
      def get_parent_class(self, env):
          c = env.get(self.var)
          if is_String(c) and not '\n' in c:
              return CommandAction
          return CommandGeneratorAction
  
      def _generate_cache(self, env):
          if env:
              c = env.get(self.var, '')
          else:
              c = ''
          gen_cmd = Action(c, **self.gen_kw)
          if not gen_cmd:
              raise SCons.Errors.UserError("$%s value %s cannot be used to create an Action." % (self.var, repr(c)))
          return gen_cmd
  
      def _generate(self, target, source, env, for_signature, executor=None):
          return self._generate_cache(env)
  
      def __call__(self, target, source, env, *args, **kw):
          c = self.get_parent_class(env)
          return c.__call__(self, target, source, env, *args, **kw)
  
      def get_presig(self, target, source, env):
          c = self.get_parent_class(env)
          return c.get_presig(self, target, source, env)
  
      def get_varlist(self, target, source, env, executor=None):
          c = self.get_parent_class(env)
          return c.get_varlist(self, target, source, env, executor)
  
  
  class FunctionAction(_ActionAction):
      """Class for Python function actions."""
  
      def __init__(self, execfunction, kw):
          if __debug__: logInstanceCreation(self, 'Action.FunctionAction')
  
          self.execfunction = execfunction
          try:
              self.funccontents = _callable_contents(execfunction)
          except AttributeError:
              try:
                  # See if execfunction will do the heavy lifting for us.
                  self.gc = execfunction.get_contents
              except AttributeError:
                  # This is weird, just do the best we can.
                  self.funccontents = _object_contents(execfunction)
  
          _ActionAction.__init__(self, **kw)
  
      def function_name(self):
          try:
              return self.execfunction.__name__
          except AttributeError:
              try:
                  return self.execfunction.__class__.__name__
              except AttributeError:
                  return "unknown_python_function"
  
      def strfunction(self, target, source, env, executor=None):
          if self.cmdstr is None:
              return None
          if self.cmdstr is not _null:
              from SCons.Subst import SUBST_RAW
              if executor:
                  c = env.subst(self.cmdstr, SUBST_RAW, executor=executor)
              else:
                  c = env.subst(self.cmdstr, SUBST_RAW, target, source)
              if c:
                  return c
          def array(a):
              def quote(s):
                  try:
                      str_for_display = s.str_for_display
                  except AttributeError:
                      s = repr(s)
                  else:
                      s = str_for_display()
                  return s
              return '[' + ", ".join(map(quote, a)) + ']'
          try:
              strfunc = self.execfunction.strfunction
          except AttributeError:
              pass
          else:
              if strfunc is None:
                  return None
              if callable(strfunc):
                  return strfunc(target, source, env)
          name = self.function_name()
          tstr = array(target)
          sstr = array(source)
          return "%s(%s, %s)" % (name, tstr, sstr)
  
      def __str__(self):
          name = self.function_name()
          if name == 'ActionCaller':
              return str(self.execfunction)
          return "%s(target, source, env)" % name
  
      def execute(self, target, source, env, executor=None):
          exc_info = (None,None,None)
          try:
              if executor:
                  target = executor.get_all_targets()
                  source = executor.get_all_sources()
              rsources = list(map(rfile, source))
              try:
                  result = self.execfunction(target=target, source=rsources, env=env)
              except KeyboardInterrupt, e:
                  raise
              except SystemExit, e:
                  raise
              except Exception, e:
                  result = e
                  exc_info = sys.exc_info()
  
              if result:
                  result = SCons.Errors.convert_to_BuildError(result, exc_info)
                  result.node=target
                  result.action=self
                  try:
                      result.command=self.strfunction(target, source, env, executor)
                  except TypeError:
                      result.command=self.strfunction(target, source, env)
  
                  # FIXME: This maintains backward compatibility with respect to
                  # which type of exceptions were returned by raising an
                  # exception and which ones were returned by value. It would
                  # probably be best to always return them by value here, but
                  # some codes do not check the return value of Actions and I do
                  # not have the time to modify them at this point.
                  if (exc_info[1] and
                      not isinstance(exc_info[1],EnvironmentError)):
                      raise result
  
              return result
          finally:
              # Break the cycle between the traceback object and this
              # function stack frame. See the sys.exc_info() doc info for
              # more information about this issue.
              del exc_info
  
  
      def get_presig(self, target, source, env):
          """Return the signature contents of this callable action."""
          try:
              return self.gc(target, source, env)
          except AttributeError:
              return self.funccontents
  
      def get_implicit_deps(self, target, source, env):
          return []
  
  class ListAction(ActionBase):
      """Class for lists of other actions."""
      def __init__(self, actionlist):
          if __debug__: logInstanceCreation(self, 'Action.ListAction')
          def list_of_actions(x):
              if isinstance(x, ActionBase):
                  return x
              return Action(x)
          self.list = list(map(list_of_actions, actionlist))
          # our children will have had any varlist
          # applied; we don't need to do it again
          self.varlist = ()
          self.targets = '$TARGETS'
  
      def genstring(self, target, source, env):
          return '\n'.join([a.genstring(target, source, env) for a in self.list])
  
      def __str__(self):
          return '\n'.join(map(str, self.list))
  
      def presub_lines(self, env):
          return SCons.Util.flatten_sequence(
              [a.presub_lines(env) for a in self.list])
  
      def get_presig(self, target, source, env):
          """Return the signature contents of this action list.
  
          Simple concatenation of the signatures of the elements.
          """
          return "".join([x.get_contents(target, source, env) for x in self.list])
  
      def __call__(self, target, source, env, exitstatfunc=_null, presub=_null,
                   show=_null, execute=_null, chdir=_null, executor=None):
          if executor:
              target = executor.get_all_targets()
              source = executor.get_all_sources()
          for act in self.list:
              stat = act(target, source, env, exitstatfunc, presub,
                         show, execute, chdir, executor)
              if stat:
                  return stat
          return 0
  
      def get_implicit_deps(self, target, source, env):
          result = []
          for act in self.list:
              result.extend(act.get_implicit_deps(target, source, env))
          return result
  
      def get_varlist(self, target, source, env, executor=None):
          result = SCons.Util.OrderedDict()
          for act in self.list:
              for var in act.get_varlist(target, source, env, executor):
                  result[var] = True
          return list(result.keys())
  
  class ActionCaller(object):
      """A class for delaying calling an Action function with specific
      (positional and keyword) arguments until the Action is actually
      executed.
  
      This class looks to the rest of the world like a normal Action object,
      but what it's really doing is hanging on to the arguments until we
      have a target, source and env to use for the expansion.
      """
      def __init__(self, parent, args, kw):
          self.parent = parent
          self.args = args
          self.kw = kw
  
      def get_contents(self, target, source, env):
          actfunc = self.parent.actfunc
          try:
              # "self.actfunc" is a function.
              contents = str(actfunc.func_code.co_code)
          except AttributeError:
              # "self.actfunc" is a callable object.
              try:
                  contents = str(actfunc.__call__.im_func.func_code.co_code)
              except AttributeError:
                  # No __call__() method, so it might be a builtin
                  # or something like that.  Do the best we can.
                  contents = str(actfunc)
          contents = remove_set_lineno_codes(contents)
          return contents
  
      def subst(self, s, target, source, env):
          # If s is a list, recursively apply subst()
          # to every element in the list
          if is_List(s):
              result = []
              for elem in s:
                  result.append(self.subst(elem, target, source, env))
              return self.parent.convert(result)
  
          # Special-case hack:  Let a custom function wrapped in an
          # ActionCaller get at the environment through which the action
          # was called by using this hard-coded value as a special return.
          if s == '$__env__':
              return env
          elif is_String(s):
              return env.subst(s, 1, target, source)
          return self.parent.convert(s)
  
      def subst_args(self, target, source, env):
          return [self.subst(x, target, source, env) for x in self.args]
  
      def subst_kw(self, target, source, env):
          kw = {}
          for key in self.kw.keys():
              kw[key] = self.subst(self.kw[key], target, source, env)
          return kw
  
      def __call__(self, target, source, env, executor=None):
          args = self.subst_args(target, source, env)
          kw = self.subst_kw(target, source, env)
          return self.parent.actfunc(*args, **kw)
  
      def strfunction(self, target, source, env):
          args = self.subst_args(target, source, env)
          kw = self.subst_kw(target, source, env)
          return self.parent.strfunc(*args, **kw)
  
      def __str__(self):
          return self.parent.strfunc(*self.args, **self.kw)
  
  class ActionFactory(object):
      """A factory class that will wrap up an arbitrary function
      as an SCons-executable Action object.
  
      The real heavy lifting here is done by the ActionCaller class.
      We just collect the (positional and keyword) arguments that we're
      called with and give them to the ActionCaller object we create,
      so it can hang onto them until it needs them.
      """
      def __init__(self, actfunc, strfunc, convert=lambda x: x):
          self.actfunc = actfunc
          self.strfunc = strfunc
          self.convert = convert
  
      def __call__(self, *args, **kw):
          ac = ActionCaller(self, args, kw)
          action = Action(ac, strfunction=ac.strfunction)
          return action
  
  # Local Variables:
  # tab-width:4
  # indent-tabs-mode:nil
  # End:
  # vim: set expandtab tabstop=4 shiftwidth=4:
  