"""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. This is what the Sig/*.py subsystem uses 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. 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 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__ = "/home/scons/scons/branch.0/baseline/src/engine/SCons/Action.py 0.97.D001 2007/05/17 11:35:19 knight" import dis import os import os.path import string import sys from SCons.Debug import logInstanceCreation import SCons.Errors import SCons.Executor import SCons.Util class _Null: pass _null = _Null print_actions = 1 execute_actions = 1 print_actions_presub = 0 default_ENV = None 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 string.join(result, '') 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): """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 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): 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) 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) return None 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) 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 __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 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): target = [target] if not SCons.Util.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 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): 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 if show and self.strfunction: s = self.strfunction(target, source, env) if s: if chdir: s = ('os.chdir(%s)\n' % repr(chdir)) + s 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) stat = 0 if execute: if chdir: os.chdir(chdir) try: stat = self.execute(target, source, env) stat = exitstatfunc(stat) finally: if save_cwd: os.chdir(save_cwd) if s 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) class CommandAction(_ActionAction): """Class for command-execution actions.""" def __init__(self, cmd, cmdstr=None, *args, **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): 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): 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: 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 flatten = SCons.Util.flatten 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 # 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(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) cmd_list, ignore, silent = self.process(target, map(rfile, source), env) # 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: return result return 0 def get_contents(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): cmd = string.join(map(str, cmd)) else: cmd = str(cmd) return env.subst_target_source(cmd, SUBST_SIG, target, source) class CommandGeneratorAction(ActionBase): """Class for command-generator actions.""" def __init__(self, generator, *args, **kw): if __debug__: logInstanceCreation(self, 'Action.CommandGeneratorAction') self.generator = generator self.gen_args = args self.gen_kw = kw 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): 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) 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 or {} except AttributeError: env = {} 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): """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) # 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 $SOURCE"), but we also # want to be able to replace them with functions in the construction # environment. Consequently, we want lazy evaluation and creation of # an Action in the case of the function, but that's overkill in the more # normal case of expansion to other strings. # # So we do this with a subclass that's both a generator *and* # a command action. The overridden methods all do a quick check # of the construction variable, and if it's a string we just call # the corresponding CommandAction method to do the heavy lifting. # If not, then we call the same-named CommandGeneratorAction method. # The CommandGeneratorAction methods work by using the overridden # _generate() method, that is, our own way of handling "generation" of # an action based on what's in the construction variable. class LazyAction(CommandGeneratorAction, CommandAction): def __init__(self, var, *args, **kw): if __debug__: logInstanceCreation(self, 'Action.LazyAction') apply(CommandAction.__init__, (self, '$'+var)+args, 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: 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) 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) return apply(c.__call__, args, kw) def get_contents(self, target, source, env): c = self.get_parent_class(env) return c.get_contents(self, target, source, env) class FunctionAction(_ActionAction): """Class for Python function actions.""" def __init__(self, execfunction, cmdstr=_null, *args, **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 apply(_ActionAction.__init__, (self,)+args, kw) self.varlist = kw.get('varlist', []) self.cmdstr = cmdstr 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: 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): return '"' + str(s) + '"' return '[' + string.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): rsources = map(rfile, source) 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 raise SCons.Errors.BuildError(node=target, errstr=e.strerror, filename=filename) return result def get_contents(self, target, source, env): """Return the signature contents of this callable action. 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. """ execfunction = self.execfunction try: # Test if execfunction is a function. code = execfunction.func_code.co_code except AttributeError: try: # Test if execfunction is a method. code = execfunction.im_func.func_code.co_code except AttributeError: try: # Test if execfunction is a callable object. code = execfunction.__call__.im_func.func_code.co_code except AttributeError: try: # See if execfunction will do the heavy lifting for us. gc = self.execfunction.get_contents except AttributeError: # This is weird, just do the best we can. contents = str(self.execfunction) else: contents = gc(target, source, env) else: contents = str(code) else: contents = str(code) else: contents = str(code) contents = remove_set_lineno_codes(contents) return contents + env.subst(string.join(map(lambda v: '${'+v+'}', self.varlist))) 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) 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(map(lambda a, env=env: a.presub_lines(env), self.list)) def get_contents(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, show=_null, execute=_null, chdir=_null): for act in self.list: stat = act(target, source, env, exitstatfunc, presub, show, execute, chdir) if stat: return stat return 0 class ActionCaller: """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): # 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 else: return env.subst(s, 0, target, source) 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) 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) return apply(self.parent.strfunc, args, kw) def __str__(self): 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): self.actfunc = actfunc self.strfunc = strfunc def __call__(self, *args, **kw): ac = ActionCaller(self, args, kw) action = Action(ac, strfunction=ac.strfunction) return action