Update to SCons 1.2.0.

third_party/scons/scons-local/SCons/Action.py

 """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.
 
@@ skipping 12 matching lines @@
 
 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.
-        This is what gets MD5 checksumm'ed to decide if a target needs
-        to be rebuilt because its action changed.
+        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 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 3603 2008/10/10 05:46:45 scons"
+__revision__ = "src/engine/SCons/Action.py 3842 2008/12/20 22:59:52 scons"
 
 import cPickle
 import dis
 import os
-import os.path
 import string
 import sys
 import subprocess
 
 from SCons.Debug import logInstanceCreation
 import SCons.Errors
 import SCons.Executor
 import SCons.Util
+import SCons.Subst
 
-class _Null:
+# we use these a lot, so try to optimize them
+is_String = SCons.Util.is_String
+is_List = SCons.Util.is_List
+
+class _null:
     pass
 
-_null = _Null
-
 print_actions = 1
 execute_actions = 1
 print_actions_presub = 0
 
 def rfile(n):
     try:
         return n.rfile()
     except AttributeError:
         return n
 
@@ skipping 40 matching lines @@
                 # 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. 
+                    # Should be a pickable Python object.
                     try:
                         return cPickle.dumps(obj)
                     except (cPickle.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. 
-    # 
+    # 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(',(' + string.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(',(' + string.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)) + ')')
 
@@ skipping 19 matching lines @@
         closure = []
 
     #xxx = [_object_contents(x.cell_contents) for x in closure]
     try:
         xxx = map(lambda x: _object_contents(x.cell_contents), closure)
     except AttributeError:
         xxx = []
     contents.append(',(' + string.join(xxx, ',') + ')')
 
     return string.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_action(act, *args, **kw):
+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 SCons.Util.is_List(act):
-        return apply(CommandAction, (act,)+args, kw)
+
+    if is_List(act):
+        #TODO(1.5) return CommandAction(act, **kw)
+        return apply(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 apply(action_type, (act,)+args, kw)
-    if SCons.Util.is_String(act):
+        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 apply(LazyAction, (var,)+args, kw)
+            return LazyAction(var, kw)
         commands = string.split(str(act), '\n')
         if len(commands) == 1:
-            return apply(CommandAction, (commands[0],)+args, kw)
-        else:
-            listCmdActions = map(lambda x, args=args, kw=kw:
-                                 apply(CommandAction, (x,)+args, kw),
-                                 commands)
-            return ListAction(listCmdActions)
+            #TODO(1.5) return CommandAction(commands[0], **kw)
+            return apply(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 None
+    elif len(acts) == 1:
+        return acts[0]
+    else:
+        return ListAction(acts)
+
 def Action(act, *args, **kw):
     """A factory for action objects."""
-    if SCons.Util.is_List(act):
-        acts = map(lambda a, args=args, kw=kw:
-                          apply(_do_create_action, (a,)+args, kw),
-                   act)
-        acts = filter(None, acts)
-        if len(acts) == 1:
-            return acts[0]
-        else:
-            return ListAction(acts)
-    else:
-        return apply(_do_create_action, (act,)+args, kw)
+    # 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:
     """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 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.varlist
+        if is_String(vl): vl = (vl,)
+        for v in vl:
+            result.append(env.subst('${'+v+'}'))
+        return string.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 = string.split(str(self), '\n')
         self.presub_env = None      # don't need this any more
         return lines
 
     def get_executor(self, env, overrides, tlist, slist, executor_kw):
         """Return the Executor for this Action."""
         return SCons.Executor.Executor(self, env, overrides,
                                        tlist, slist, executor_kw)
 
 class _ActionAction(ActionBase):
     """Base class for actions that create output objects."""
-    def __init__(self, strfunction=_null, presub=_null, chdir=None, exitstatfunc=None, **kw):
-        if not strfunction is _null:
-            self.strfunction = strfunction
+    def __init__(self, cmdstr=_null, strfunction=_null, varlist=(),
+                       presub=_null, chdir=None, exitstatfunc=None,
+                 **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
 
     def print_cmd_line(self, s, target, source, env):
         sys.stdout.write(s + "\n")
 
     def __call__(self, target, source, env,
                                exitstatfunc=_null,
                                presub=_null,
                                show=_null,
                                execute=_null,
                                chdir=_null):
-        if not SCons.Util.is_List(target):
+        if not is_List(target):
             target = [target]
-        if not SCons.Util.is_List(source):
+        if not is_List(source):
             source = [source]
 
-        if exitstatfunc is _null: exitstatfunc = self.exitstatfunc
         if presub is _null:
             presub = self.presub
-        if presub is _null:
-            presub = print_actions_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 SCons.Util.is_String(chdir):
+                if not is_String(chdir):
                     chdir = str(target[0].dir)
         if presub:
             t = string.join(map(str, target), ' and ')
             l = string.join(self.presub_lines(env), '\n  ')
             out = "Building %s with action:\n  %s\n" % (t, l)
             sys.stdout.write(out)
-        s = None
+        cmd = None
         if show and self.strfunction:
-            s = self.strfunction(target, source, env)
-            if s:
+            cmd = self.strfunction(target, source, env)
+            if cmd:
                 if chdir:
-                    s = ('os.chdir(%s)\n' % repr(chdir)) + s
+                    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(s, target, source, env)
+                print_func(cmd, target, source, env)
         stat = 0
         if execute:
             if chdir:
                 os.chdir(chdir)
             try:
                 stat = self.execute(target, source, env)
                 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 s and 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 string.join(cl)
 
-# 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 it, but I'm sure it'll have
-# to be tweaked to get the full desired functionality.
+# 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
-# one special arg, 'error', to tell what to do with exceptions.
+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(env, cmd, error = 'ignore', **kw):
-    """Do setup for a subprocess.Popen() call"""
+    """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')
 
-    # If the env has no ENV, get a default
-    try:
-        ENV = env['ENV']
-    except KeyError:
-        global default_ENV
-        if default_ENV is None:
-            # Unbelievably expensive.  What it really should do
-            # is run the platform setup to get the default ENV.
-            # Fortunately, it should almost never happen.
-            default_ENV = SCons.Environment.Environment(tools=[])['ENV']
-        ENV = default_ENV
-    
+    # Figure out what shell environment to use
+    ENV = kw.get('env', None)
+    if ENV is None: ENV = get_default_ENV(env)
+
     # Ensure that the ENV values are all strings:
     new_env = {}
-    # It's a string 99.44% of the time, so optimize this
-    is_String = SCons.Util.is_String
     for key, value in ENV.items():
-        if is_String(value):
-            # Call str() even though it's a "string" because it might be
-            # a *Unicode* string, which makes subprocess.Popen() gag.
+        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] = string.join(map(str, value), os.pathsep)
+        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)
-        elif SCons.Util.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)
-            ENV[key] = string.join(map(str, value), os.pathsep)
-        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)
     kw['env'] = new_env
 
     try:
         #FUTURE return subprocess.Popen(cmd, **kw)
         return apply(subprocess.Popen, (cmd,), kw)
     except EnvironmentError, e:
         if error == 'raise': raise
         # return a dummy Popen instance that only returns error
-        class popen:
+        class dummyPopen:
             def __init__(self, e): self.exception = e
             def communicate(self): return ('','')
             def wait(self): return -self.exception.errno
             stdin = None
             class f:
                 def read(self): return ''
                 def readline(self): return ''
             stdout = stderr = f()
-        return popen(e)
+        return dummyPopen(e)
 
 class CommandAction(_ActionAction):
     """Class for command-execution actions."""
-    def __init__(self, cmd, cmdstr=None, *args, **kw):
+    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')
 
-        if not cmdstr is None:
-            if callable(cmdstr):
-                args = (cmdstr,)+args
-            elif not SCons.Util.is_String(cmdstr):
-                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.')
-
-        apply(_ActionAction.__init__, (self,)+args, kw)
-        if SCons.Util.is_List(cmd):
-            if filter(SCons.Util.is_List, cmd):
+        #TODO(1.5) _ActionAction.__init__(self, **kw)
+        apply(_ActionAction.__init__, (self,), kw)
+        if is_List(cmd):
+            if filter(is_List, cmd):
                 raise TypeError, "CommandAction should be given only " \
                       "a single command"
         self.cmd_list = cmd
-        self.cmdstr = cmdstr
 
     def __str__(self):
-        if SCons.Util.is_List(self.cmd_list):
+        if is_List(self.cmd_list):
             return string.join(map(str, self.cmd_list), ' ')
         return str(self.cmd_list)
 
     def process(self, target, source, env):
         result = env.subst_list(self.cmd_list, 0, target, source)
         silent = None
         ignore = None
         while 1:
             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):
-        if not self.cmdstr is None:
+        if self.cmdstr is None:
+            return None
+        if self.cmdstr is not _null:
             from SCons.Subst import SUBST_RAW
             c = env.subst(self.cmdstr, SUBST_RAW, target, source)
             if c:
                 return c
         cmd_list, ignore, silent = self.process(target, source, env)
         if silent:
             return ''
         return _string_from_cmd_list(cmd_list[0])
 
     def execute(self, target, source, env):
         """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.
         """
-        from SCons.Subst import escape_list
-        import SCons.Util
+        escape_list = SCons.Subst.escape_list
         flatten_sequence = SCons.Util.flatten_sequence
-        is_String = SCons.Util.is_String
-        is_List = SCons.Util.is_List
 
         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)
 
-        try:
-            ENV = env['ENV']
-        except KeyError:
-            global default_ENV
-            if not default_ENV:
-                import SCons.Environment
-                default_ENV = SCons.Environment.Environment()['ENV']
-            ENV = default_ENV
+        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] = string.join(map(str, value), os.pathsep)
@@ skipping 12 matching lines @@
             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_contents(self, target, source, env):
+    def get_presig(self, target, source, env):
         """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 SCons.Util.is_List(cmd):
+        if is_List(cmd):
             cmd = string.join(map(str, cmd))
         else:
             cmd = str(cmd)
         return env.subst_target_source(cmd, SUBST_SIG, target, source)
 
     def get_implicit_deps(self, target, source, env):
         icd = env.get('IMPLICIT_COMMAND_DEPENDENCIES', True)
-        if SCons.Util.is_String(icd) and icd[:1] == '$':
+        if is_String(icd) and icd[:1] == '$':
             icd = env.subst(icd)
         if not icd or icd in ('0', 'None'):
             return []
         from SCons.Subst import SUBST_SIG
         cmd_list = env.subst_list(self.cmd_list, SUBST_SIG, target, source)
         res = []
         for cmd_line in cmd_list:
             if cmd_line:
                 d = env.WhereIs(str(cmd_line[0]))
                 if d:
                     res.append(env.fs.File(d))
         return res
 
 class CommandGeneratorAction(ActionBase):
     """Class for command-generator actions."""
-    def __init__(self, generator, *args, **kw):
+    def __init__(self, generator, kw):
         if __debug__: logInstanceCreation(self, 'Action.CommandGeneratorAction')
         self.generator = generator
-        self.gen_args = args
         self.gen_kw = kw
+        self.varlist = kw.get('varlist', ())
 
     def _generate(self, target, source, env, for_signature):
         # ensure that target is a list, to make it easier to write
         # generator functions:
-        if not SCons.Util.is_List(target):
+        if not is_List(target):
             target = [target]
 
         ret = self.generator(target=target, source=source, env=env, for_signature=for_signature)
-        gen_cmd = apply(Action, (ret,)+self.gen_args, self.gen_kw)
+        #TODO(1.5) gen_cmd = Action(ret, **self.gen_kw)
+        gen_cmd = apply(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 genstring(self, target, source, env):
         return self._generate(target, source, env, 1).genstring(target, source, env)
 
     def __call__(self, target, source, env, exitstatfunc=_null, presub=_null,
                  show=_null, execute=_null, chdir=_null):
         act = self._generate(target, source, env, 0)
         return act(target, source, env, exitstatfunc, presub,
                    show, execute, chdir)
 
-    def get_contents(self, target, source, env):
+    def get_presig(self, target, source, env):
         """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).get_contents(target, source, env)
+        return self._generate(target, source, env, 1).get_presig(target, source, env)
 
     def get_implicit_deps(self, target, source, env):
         return self._generate(target, source, env, 1).get_implicit_deps(target, source, env)
 
 
 
 # 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, *args, **kw):
+    def __init__(self, var, kw):
         if __debug__: logInstanceCreation(self, 'Action.LazyAction')
-        apply(CommandAction.__init__, (self, '$'+var)+args, kw)
+        #FUTURE CommandAction.__init__(self, '${'+var+'}', **kw)
+        apply(CommandAction.__init__, (self, '${'+var+'}'), kw)
         self.var = SCons.Util.to_String(var)
-        self.gen_args = args
         self.gen_kw = kw
 
     def get_parent_class(self, env):
         c = env.get(self.var)
-        if SCons.Util.is_String(c) and not '\n' in c:
+        if is_String(c) and not '\n' in c:
             return CommandAction
         return CommandGeneratorAction
 
     def _generate_cache(self, env):
         c = env.get(self.var, '')
-        gen_cmd = apply(Action, (c,)+self.gen_args, self.gen_kw)
+        #TODO(1.5) gen_cmd = Action(c, **self.gen_kw)
+        gen_cmd = apply(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):
         return self._generate_cache(env)
 
     def __call__(self, target, source, env, *args, **kw):
         args = (self, target, source, env) + args
         c = self.get_parent_class(env)
+        #TODO(1.5) return c.__call__(*args, **kw)
         return apply(c.__call__, args, kw)
 
-    def get_contents(self, target, source, env):
+    def get_presig(self, target, source, env):
         c = self.get_parent_class(env)
-        return c.get_contents(self, target, source, env)
+        return c.get_presig(self, target, source, env)
 
 
 
 class FunctionAction(_ActionAction):
     """Class for Python function actions."""
 
-    def __init__(self, execfunction, cmdstr=_null, *args, **kw):
+    def __init__(self, execfunction, kw):
         if __debug__: logInstanceCreation(self, 'Action.FunctionAction')
 
-        if not cmdstr is _null:
-            if callable(cmdstr):
-                args = (cmdstr,)+args
-            elif not (cmdstr is None or SCons.Util.is_String(cmdstr)):
-                raise SCons.Errors.UserError(\
-                    'Invalid function display variable type. ' \
-                    'You must either pass a string or a callback which ' \
-                    'accepts (target, source, env) as parameters.')
-
         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)
 
-        apply(_ActionAction.__init__, (self,)+args, kw)
-        self.varlist = kw.get('varlist', [])
-        if SCons.Util.is_String(self.varlist):
-            # prevent varlist="FOO" from being interpreted as ['F', 'O', 'O']
-            self.varlist=[self.varlist]
-        self.cmdstr = cmdstr
+        #TODO(1.5) _ActionAction.__init__(self, **kw)
+        apply(_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):
         if self.cmdstr is None:
             return None
-        if not self.cmdstr is _null:
+        if self.cmdstr is not _null:
             from SCons.Subst import SUBST_RAW
             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)
@@ skipping 15 matching lines @@
         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):
-        rsources = map(rfile, source)
+        exc_info = (None,None,None)
         try:
-            result = self.execfunction(target=target, source=rsources, env=env)
-        except EnvironmentError, e:
-            # If an IOError/OSError happens, raise a BuildError.
-            # Report the name of the file or directory that caused the
-            # error, which might be different from the target being built
-            # (for example, failure to create the directory in which the
-            # target file will appear).
-            try: filename = e.filename
-            except AttributeError: filename = None
-            result = SCons.Errors.BuildError(node=target,
-                                             errstr=e.strerror,
-                                             status=1,
-                                             filename=filename,
-                                             action=self,
-                                             command=self.strfunction(target, source, env))
-        else:
+            rsources = 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:
-                msg = "Error %s" % result
-                result = SCons.Errors.BuildError(errstr=msg,
-                                                 status=result,
-                                                 action=self,
-                                                 command=self.strfunction(target, source, env))
-        return result
+                result = SCons.Errors.convert_to_BuildError(result, exc_info)
+                result.node=target
+                result.action=self
+                result.command=self.strfunction(target, source, env)
 
-    def get_contents(self, 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:
-            contents = self.gc(target, source, env)
+            return self.gc(target, source, env)
         except AttributeError:
-            contents = self.funccontents
-
-        result = [contents]
-        for v in self.varlist:
-            result.append(env.subst('${'+v+'}'))
-
-        return string.join(result, '')
+            return self.funccontents
 
     def get_implicit_deps(self, target, source, env):
         return []
 
 class ListAction(ActionBase):
     """Class for lists of other actions."""
     def __init__(self, list):
         if __debug__: logInstanceCreation(self, 'Action.ListAction')
         def list_of_actions(x):
             if isinstance(x, ActionBase):
                 return x
             return Action(x)
         self.list = map(list_of_actions, list)
+        # our children will have had any varlist
+        # applied; we don't need to do it again
+        self.varlist = ()
 
     def genstring(self, target, source, env):
         return string.join(map(lambda a, t=target, s=source, e=env:
                                   a.genstring(t, s, e),
                                self.list),
                            '\n')
 
     def __str__(self):
         return string.join(map(str, self.list), '\n')
-    
+
     def presub_lines(self, env):
         return SCons.Util.flatten_sequence(
             map(lambda a, env=env: a.presub_lines(env), self.list))
 
-    def get_contents(self, target, source, env):
+    def get_presig(self, target, source, env):
         """Return the signature contents of this action list.
 
         Simple concatenation of the signatures of the elements.
         """
         return string.join(map(lambda x, t=target, s=source, e=env:
                                       x.get_contents(t, s, e),
                                self.list),
                            "")
 
     def __call__(self, target, source, env, exitstatfunc=_null, presub=_null,
@@ skipping 17 matching lines @@
     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 SCons.Util.is_List(s):
+        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 SCons.Util.is_String(s):
+        elif is_String(s):
             return env.subst(s, 1, target, source)
         return self.parent.convert(s)
+
     def subst_args(self, target, source, env):
         return map(lambda x, self=self, t=target, s=source, e=env:
                           self.subst(x, t, s, e),
                    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):
         args = self.subst_args(target, source, env)
         kw = self.subst_kw(target, source, env)
+        #TODO(1.5) return self.parent.actfunc(*args, **kw)
         return apply(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)
+        #TODO(1.5) return self.parent.strfunc(*args, **kw)
         return apply(self.parent.strfunc, args, kw)
+
     def __str__(self):
+        #TODO(1.5) return self.parent.strfunc(*self.args, **self.kw)
         return apply(self.parent.strfunc, self.args, self.kw)
 
 class ActionFactory:
     """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