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TaskGen.py

#!/usr/bin/env python
# encoding: utf-8
# Thomas Nagy, 2005-2008 (ita)

"""
The class task_gen encapsulates the creation of task objects (low-level code)
The instances can have various parameters, but the creation of task nodes (Task.py)
is delayed. To achieve this, various methods are called from the method "apply"

The class task_gen contains lots of methods, and a configuration table:
* the methods to call (self.meths) can be specified dynamically (removing, adding, ..)
* the order of the methods (self.prec or by default task_gen.prec) is configurable
* new methods can be inserted dynamically without pasting old code

Additionally, task_gen provides the method apply_core
* file extensions are mapped to methods: def meth(self, name_or_node)
* if a mapping is not found in self.mappings, it is searched in task_gen.mappings
* when called, the functions may modify self.allnodes to re-add source to process
* the mappings can map an extension or a filename (see the code below)

WARNING: subclasses must reimplement the clone method
"""

import os, traceback, copy
import Build, Task, Utils, Logs, Options
from Logs import debug, error, warn
from Constants import *

typos = {
'sources':'source',
'targets':'target',
'include':'includes',
'define':'defines',
'importpath':'importpaths',
'install_var':'install_path',
'install_subdir':'install_path',
'inst_var':'install_path',
'inst_dir':'install_path',
'feature':'features',
}

00042 class register_obj(type):
      """no decorators for classes, so we use a metaclass
      we store into task_gen.classes the classes that inherit task_gen
      and whose names end in '_taskgen'
      """
      def __init__(cls, name, bases, dict):
            super(register_obj, cls).__init__(name, bases, dict)
            name = cls.__name__
            suffix = '_taskgen'
            if name.endswith(suffix):
                  task_gen.classes[name.replace(suffix, '')] = cls

00054 class task_gen(object):
      """
      Most methods are of the form 'def meth(self):' without any parameters
      there are many of them, and they do many different things:
      * task creation
      * task results installation
      * environment modification
      * attribute addition/removal

      The inheritance approach is complicated
      * mixing several languages at once
      * subclassing is needed even for small changes
      * inserting new methods is complicated

      This new class uses a configuration table:
      * adding new methods easily
      * obtaining the order in which to call the methods
      * postponing the method calls (post() -> apply)

      Additionally, a 'traits' static attribute is provided:
      * this list contains methods
      * the methods can remove or add methods from self.meths
      Example1: the attribute 'staticlib' is set on an instance
      a method set in the list of traits is executed when the
      instance is posted, it finds that flag and adds another method for execution
      Example2: a method set in the list of traits finds the msvc
      compiler (from self.env['MSVC']==1); more methods are added to self.meths
      """

      __metaclass__ = register_obj
      mappings = {}
      mapped = {}
      prec = Utils.DefaultDict(list)
      traits = Utils.DefaultDict(set)
      classes = {}

      def __init__(self, *kw, **kwargs):
            self.prec = Utils.DefaultDict(list)
            "map precedence of function names to call"
            # so we will have to play with directed acyclic graphs
            # detect cycles, etc

            self.source = ''
            self.target = ''

            # list of methods to execute - does not touch it by hand unless you know
            self.meths = []

            # list of mappings extension -> function
            self.mappings = {}

            # list of features (see the documentation on traits)
            self.features = list(kw)

            # not always a good idea
            self.tasks = []

            self.default_chmod = O644
            self.default_install_path = None

            # kind of private, beware of what you put in it, also, the contents are consumed
            self.allnodes = []

            self.bld = kwargs.get('bld', Build.bld)
            self.env = self.bld.env.copy()

            self.path = self.bld.path # emulate chdir when reading scripts
            self.name = '' # give a name to the target (static+shlib with the same targetname ambiguity)

            # provide a unique id
            self.idx = self.bld.idx[self.path.id] = self.bld.idx.get(self.path.id, 0) + 1

            for key, val in kwargs.iteritems():
                  setattr(self, key, val)

            self.bld.task_manager.add_task_gen(self)
            self.bld.all_task_gen.append(self)

      def __str__(self):
            return ("<task_gen '%s' of type %s defined in %s>"
                  % (self.name or self.target, self.__class__.__name__, str(self.path)))

      def __setattr__(self, name, attr):
            real = typos.get(name, name)
            if real != name:
                  warn('typo %s -> %s' % (name, real))
                  if Logs.verbose > 0:
                        traceback.print_stack()
            object.__setattr__(self, real, attr)

      def to_list(self, value):
            "helper: returns a list"
            if isinstance(value, str): return value.split()
            else: return value

      def apply(self):
            "order the methods to execute using self.prec or task_gen.prec"
            keys = set(self.meths)

            # add the methods listed in the features
            self.features = Utils.to_list(self.features)
            for x in self.features + ['*']:
                  st = task_gen.traits[x]
                  if not st:
                        warn('feature %r does not exist - bind at least one method to it' % x)
                  keys.update(st)

            # copy the precedence table
            prec = {}
            prec_tbl = self.prec or task_gen.prec
            for x in prec_tbl:
                  if x in keys:
                        prec[x] = prec_tbl[x]

            # elements disconnected
            tmp = []
            for a in keys:
                  for x in prec.values():
                        if a in x: break
                  else:
                        tmp.append(a)

            # topological sort
            out = []
            while tmp:
                  e = tmp.pop()
                  if e in keys: out.append(e)
                  try:
                        nlst = prec[e]
                  except KeyError:
                        pass
                  else:
                        del prec[e]
                        for x in nlst:
                              for y in prec:
                                    if x in prec[y]:
                                          break
                              else:
                                    tmp.append(x)

            if prec: raise Utils.WafError("graph has a cycle %s" % str(prec))
            out.reverse()
            self.meths = out

            # then we run the methods in order
            debug('task_gen: posting %s %d' % (self, id(self)))
            for x in out:
                  try:
                        v = getattr(self, x)
                  except AttributeError:
                        raise Utils.WafError("tried to retrieve %s which is not a valid method" % x)
                  debug('task_gen: -> %s (%d)' % (x, id(self)))
                  v()

      def post(self):
            "runs the code to create the tasks, do not subclass"
            if not self.name:
                  if isinstance(self.target, list):
                        self.name = ' '.join(self.target)
                  else:
                        self.name = self.target

            if getattr(self, 'posted', None):
                  #error("OBJECT ALREADY POSTED" + str( self))
                  return
            self.apply()
            debug('task_gen: posted %s' % self.name)
            self.posted = True

      def get_hook(self, ext):
            try: return self.mappings[ext]
            except KeyError:
                  try: return task_gen.mappings[ext]
                  except KeyError: return None

      # TODO waf 1.6: always set the environment
      # TODO waf 1.6: create_task(self, name, inputs, outputs)
      def create_task(self, name, src=None, tgt=None, env=None):
            env = env or self.env
            task = Task.TaskBase.classes[name](env.copy(), generator=self)
            if src:
                  task.set_inputs(src)
            if tgt:
                  task.set_outputs(tgt)
            self.tasks.append(task)
            return task

      def name_to_obj(self, name):
            return self.bld.name_to_obj(name, self.env)

00244       def find_sources_in_dirs(self, dirnames, excludes=[], exts=[]):
            """
            The attributes "excludes" and "exts" must be lists to avoid the confusion
            find_sources_in_dirs('a', 'b', 'c') <-> find_sources_in_dirs('a b c')

            do not use absolute paths
            do not use paths outside of the source tree
            the files or folder beginning by . are not returned

            # TODO: remove in Waf 1.6
            """

            err_msg = "'%s' attribute must be a list"
            if not isinstance(excludes, list):
                  raise Utils.WscriptError(err_msg % 'excludes')
            if not isinstance(exts, list):
                  raise Utils.WscriptError(err_msg % 'exts')

            lst = []

            #make sure dirnames is a list helps with dirnames with spaces
            dirnames = self.to_list(dirnames)

            ext_lst = exts or list(self.mappings.keys()) + list(task_gen.mappings.keys())

            for name in dirnames:
                  anode = self.path.find_dir(name)

                  if not anode or not anode.is_child_of(self.bld.srcnode):
                        raise Utils.WscriptError("Unable to use '%s' - either because it's not a relative path" \
                               ", or it's not child of '%s'." % (name, self.bld.srcnode))

                  self.bld.rescan(anode)
                  for name in self.bld.cache_dir_contents[anode.id]:

                        # ignore hidden files
                        if name.startswith('.'):
                              continue

                        (base, ext) = os.path.splitext(name)
                        if ext in ext_lst and not name in lst and not name in excludes:
                              lst.append((anode.relpath_gen(self.path) or '.') + os.path.sep + name)

            lst.sort()
            self.source = self.to_list(self.source)
            if not self.source: self.source = lst
            else: self.source += lst

      def clone(self, env):
            ""
            newobj = task_gen(bld=self.bld)
            for x in self.__dict__:
                  if x in ['env', 'bld']:
                        continue
                  elif x in ["path", "features"]:
                        setattr(newobj, x, getattr(self, x))
                  else:
                        setattr(newobj, x, copy.copy(getattr(self, x)))

            newobj.__class__ = self.__class__
            if isinstance(env, str):
                  newobj.env = self.bld.all_envs[env].copy()
            else:
                  newobj.env = env.copy()

            return newobj

      def get_inst_path(self):
            return getattr(self, '_install_path', getattr(self, 'default_install_path', ''))

      def set_inst_path(self, val):
            self._install_path = val

      install_path = property(get_inst_path, set_inst_path)


      def get_chmod(self):
            return getattr(self, '_chmod', getattr(self, 'default_chmod', O644))

      def set_chmod(self, val):
            self._chmod = val

      chmod = property(get_chmod, set_chmod)

def declare_extension(var, func):
      try:
            for x in Utils.to_list(var):
                  task_gen.mappings[x] = func
      except:
            raise Utils.WscriptError('declare_extension takes either a list or a string %r' % var)
      task_gen.mapped[func.__name__] = func

def declare_order(*k):
      assert(len(k) > 1)
      n = len(k) - 1
      for i in xrange(n):
            f1 = k[i]
            f2 = k[i+1]
            if not f1 in task_gen.prec[f2]:
                  task_gen.prec[f2].append(f1)

def declare_chain(name='', action='', ext_in='', ext_out='', reentrant=1, color='BLUE',
      install=0, before=[], after=[], decider=None, rule=None, scan=None):
      """
      see Tools/flex.py for an example
      while i do not like such wrappers, some people really do
      """

      action = action or rule
      if isinstance(action, str):
            act = Task.simple_task_type(name, action, color=color)
      else:
            act = Task.task_type_from_func(name, action, color=color)
      act.ext_in = tuple(Utils.to_list(ext_in))
      act.ext_out = tuple(Utils.to_list(ext_out))
      act.before = Utils.to_list(before)
      act.after = Utils.to_list(after)
      act.scan = scan

      def x_file(self, node):
            if decider:
                  ext = decider(self, node)
            elif isinstance(ext_out, str):
                  ext = ext_out

            if isinstance(ext, str):
                  out_source = node.change_ext(ext)
                  if reentrant:
                        self.allnodes.append(out_source)
            elif isinstance(ext, list):
                  out_source = [node.change_ext(x) for x in ext]
                  if reentrant:
                        for i in xrange(reentrant):
                              self.allnodes.append(out_source[i])
            else:
                  # XXX: useless: it will fail on Utils.to_list above...
                  raise Utils.WafError("do not know how to process %s" % str(ext))

            tsk = self.create_task(name, node, out_source)

            if node.__class__.bld.is_install:
                  tsk.install = install

      declare_extension(act.ext_in, x_file)

def bind_feature(name, methods):
      lst = Utils.to_list(methods)
      task_gen.traits[name].update(lst)

"""
All the following decorators are registration decorators, i.e add an attribute to current class
 (task_gen and its derivatives), with same name as func, which points to func itself.
For example:
   @taskgen
   def sayHi(self):
        print("hi")
Now taskgen.sayHi() may be called

If python were really smart, it could infer itself the order of methods by looking at the
attributes. A prerequisite for execution is to have the attribute set before.
Intelligent compilers binding aspect-oriented programming and parallelization, what a nice topic for studies.
"""
def taskgen(func):
      setattr(task_gen, func.__name__, func)

def feature(*k):
      def deco(func):
            setattr(task_gen, func.__name__, func)
            for name in k:
                  task_gen.traits[name].update([func.__name__])
            return func
      return deco

def before(*k):
      def deco(func):
            setattr(task_gen, func.__name__, func)
            for fun_name in k:
                  if not func.__name__ in task_gen.prec[fun_name]:
                        task_gen.prec[fun_name].append(func.__name__)
            return func
      return deco

def after(*k):
      def deco(func):
            setattr(task_gen, func.__name__, func)
            for fun_name in k:
                  if not fun_name in task_gen.prec[func.__name__]:
                        task_gen.prec[func.__name__].append(fun_name)
            return func
      return deco

def extension(var):
      def deco(func):
            setattr(task_gen, func.__name__, func)
            try:
                  for x in Utils.to_list(var):
                        task_gen.mappings[x] = func
            except:
                  raise Utils.WafError('extension takes either a list or a string %r' % var)
            task_gen.mapped[func.__name__] = func
            return func
      return deco

# TODO make certain the decorators may be used here

def apply_core(self):
      """Process the attribute source
      transform the names into file nodes
      try to process the files by name first, later by extension"""
      # get the list of folders to use by the scanners
      # all our objects share the same include paths anyway
      find_resource = self.path.find_resource

      for filename in self.to_list(self.source):
            # if self.mappings or task_gen.mappings contains a file of the same name
            x = self.get_hook(filename)
            if x:
                  x(self, filename)
            else:
                  node = find_resource(filename)
                  if not node: raise Utils.WafError("source not found: '%s' in '%s'" % (filename, str(self.path)))
                  self.allnodes.append(node)

      for node in self.allnodes:
            # self.mappings or task_gen.mappings map the file extension to a function
            x = self.get_hook(node.suffix())

            if not x:
                  raise Utils.WafError("Cannot guess how to process %s (got mappings %r in %r) -> try conf.check_tool(..)?" % \
                        (str(node), self.__class__.mappings.keys(), self.__class__))
            x(self, node)
feature('*')(apply_core)

def exec_rule(self):
      """Process the attribute rule, when provided the method apply_core will be disabled
      """
      if not getattr(self, 'rule', None):
            return

      # someone may have removed it already
      try:
            self.meths.remove('apply_core')
      except ValueError:
            pass

      # get the function and the variables
      func = self.rule
      vars2 = []
      if isinstance(func, str):
            # use the shell by default for user-defined commands
            (func, vars2) = Task.compile_fun('', self.rule, shell=getattr(self, 'shell', True))
            func.code = self.rule
      vars = getattr(self, 'vars', vars2)
      if not vars:
            if isinstance(self.rule, str):
                  vars = self.rule
            else:
                  vars = Utils.h_fun(self.rule)

      # create the task class
      name = getattr(self, 'name', None) or self.target or self.rule
      cls = Task.task_type_from_func(name, func, vars)

      # now create one instance
      tsk = self.create_task(name)

      # we assume that the user knows that without inputs or outputs
      #if not getattr(self, 'target', None) and not getattr(self, 'source', None):
      #     cls.quiet = True

      if getattr(self, 'target', None):
            cls.quiet = True
            tsk.outputs = [self.path.find_or_declare(x) for x in self.to_list(self.target)]

      if getattr(self, 'source', None):
            cls.quiet = True
            tsk.inputs = []
            for x in self.to_list(self.source):
                  y = self.path.find_resource(x)
                  if not y:
                        raise Utils.WafError('input file %r could not be found (%r)' % (x, self.path.abspath()))
                  tsk.inputs.append(y)

      if getattr(self, 'always', None):
            Task.always_run(cls)

      if getattr(self, 'scan', None):
            cls.scan = self.scan

      if getattr(self, 'install_path', None):
            tsk.install_path = self.install_path

      if getattr(self, 'cwd', None):
            tsk.cwd = self.cwd

      if getattr(self, 'on_results', None):
            Task.update_outputs(cls)

      for x in ['after', 'before']:
            setattr(cls, x, getattr(self, x, []))
feature('*')(exec_rule)
before('apply_core')(exec_rule)

def sequence_order(self):
      """
      add a strict sequential constraint between the tasks generated by task generators
      it uses the fact that task generators are posted in order
      it will not post objects which belong to other folders
      there is also an awesome trick for executing the method in last position

      to use:
      bld.new_task_gen(features='javac seq')
      bld.new_task_gen(features='jar seq')

      to start a new sequence, set the attribute seq_start, for example:
      obj.seq_start = True
      """
      if self.meths and self.meths[-1] != 'sequence_order':
            self.meths.append('sequence_order')
            return

      if getattr(self, 'seq_start', None):
            return

      # all the tasks previously declared must be run before these
      if getattr(self.bld, 'prev', None):
            self.bld.prev.post()
            for x in self.bld.prev.tasks:
                  for y in self.tasks:
                        y.set_run_after(x)

      self.bld.prev = self

feature('seq')(sequence_order)


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