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#!/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 (
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 = {
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
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 = '' = ''
# 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 = '' # give a name to the target (static+shlib with the same targetname ambiguity)
# provide a unique id
self.idx = self.bld.idx[] = self.bld.idx.get(, 0) + 1
for key, val in kwargs.iteritems():
setattr(self, key, val)
def __str__(self):
return ("<task_gen '%s' of type %s defined in %s>"
% ( or, 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:
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)
# 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
# topological sort
out = []
while tmp:
e = tmp.pop()
if e in keys: out.append(e)
nlst = prec[e]
except KeyError:
del prec[e]
for x in nlst:
for y in prec:
if x in prec[y]:
if prec: raise Utils.WafError("graph has a cycle %s" % str(prec))
self.meths = out
# then we run the methods in order
debug('task_gen: posting %s %d', self, id(self))
for x in out:
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))
def post(self):
"runs the code to create the tasks, do not subclass"
if not
if isinstance(, list): = ' '.join(
else: =
if getattr(self, 'posted', None):
#error("OBJECT ALREADY POSTED" + str( self))
debug('task_gen: posted %s',
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:
if tgt:
return task
def name_to_obj(self, name):
return self.bld.name_to_obj(name, self.env)
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))
for name in self.bld.cache_dir_contents[]:
# ignore hidden files
if name.startswith('.'):
(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)
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']:
elif x in ["path", "features"]:
setattr(newobj, x, getattr(self, x))
setattr(newobj, x, copy.copy(getattr(self, x)))
newobj.__class__ = self.__class__
if isinstance(env, str):
newobj.env = self.bld.all_envs[env].copy()
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):
for x in Utils.to_list(var):
task_gen.mappings[x] = func
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]:
def declare_chain(name='', action='', ext_in='', ext_out='', reentrant=True, color='BLUE',
install=0, before=[], after=[], decider=None, rule=None, scan=None):
see Tools/ 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)
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)
ext = ext_out
if isinstance(ext, str):
out_source = node.change_ext(ext)
if reentrant:
elif isinstance(ext, list):
out_source = [node.change_ext(x) for x in ext]
if reentrant:
for i in xrange((reentrant is True) and len(out_source) or reentrant):
# 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)
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:
def sayHi(self):
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)
return func
def feature(*k):
def deco(func):
setattr(task_gen, func.__name__, func)
for name in k:
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]:
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__]:
return func
return deco
def extension(var):
def deco(func):
setattr(task_gen, func.__name__, func)
for x in Utils.to_list(var):
task_gen.mappings[x] = func
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)
node = find_resource(filename)
if not node: raise Utils.WafError("source not found: '%s' in '%s'" % (filename, str(self.path)))
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)
def exec_rule(self):
"""Process the attribute rule, when provided the method apply_core will be disabled
if not getattr(self, 'rule', None):
# someone may have removed it already
except ValueError:
# 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
# create the task class
name = getattr(self, 'name', None) or or self.rule
if not isinstance(name, str):
name = str(self.idx)
cls = Task.task_type_from_func(name, func, getattr(self, 'vars', vars2))
# now create one instance
tsk = self.create_task(name)
dep_vars = getattr(self, 'dep_vars', ['ruledeps'])
if dep_vars:
tsk.dep_vars = dep_vars
if isinstance(self.rule, str):
tsk.env.ruledeps = self.rule
# only works if the function is in a global module such as a waf tool
tsk.env.ruledeps = Utils.h_fun(self.rule)
# 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(]
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()))
if self.allnodes:
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):
if getattr(self, 'always', None):
for x in ['after', 'before', 'ext_in', 'ext_out']:
setattr(cls, x, getattr(self, x, []))
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(features='javac seq')
bld(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':
if getattr(self, 'seq_start', None):
# all the tasks previously declared must be run before these
if getattr(self.bld, 'prev', None):
for x in self.bld.prev.tasks:
for y in self.tasks:
self.bld.prev = self
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