third_party/waf/waflib/Context.py

   1 #!/usr/bin/env python
   2 # encoding: utf-8
   3 # Thomas Nagy, 2010-2018 (ita)
   4
   5 """
   6 Classes and functions enabling the command system
   7 """
   8
   9 import os, re, sys
  10 from waflib import Utils, Errors, Logs
  11 import waflib.Node
  12
  13 if sys.hexversion > 0x3040000:
  14         import types
  15         class imp(object):
  16                 new_module = lambda x: types.ModuleType(x)
  17 else:
  18         import imp
  19
  20 # the following 3 constants are updated on each new release (do not touch)
  21 HEXVERSION=0x2001a00
  22 """Constant updated on new releases"""
  23
  24 WAFVERSION="2.0.26"
  25 """Constant updated on new releases"""
  26
  27 WAFREVISION="0fb985ce1932c6f3e7533f435e4ee209d673776e"
  28 """Git revision when the waf version is updated"""
  29
  30 WAFNAME="waf"
  31 """Application name displayed on --help"""
  32
  33 ABI = 20
  34 """Version of the build data cache file format (used in :py:const:`waflib.Context.DBFILE`)"""
  35
  36 DBFILE = '.wafpickle-%s-%d-%d' % (sys.platform, sys.hexversion, ABI)
  37 """Name of the pickle file for storing the build data"""
  38
  39 APPNAME = 'APPNAME'
  40 """Default application name (used by ``waf dist``)"""
  41
  42 VERSION = 'VERSION'
  43 """Default application version (used by ``waf dist``)"""
  44
  45 TOP  = 'top'
  46 """The variable name for the top-level directory in wscript files"""
  47
  48 OUT  = 'out'
  49 """The variable name for the output directory in wscript files"""
  50
  51 WSCRIPT_FILE = 'wscript'
  52 """Name of the waf script files"""
  53
  54 launch_dir = ''
  55 """Directory from which waf has been called"""
  56 run_dir = ''
  57 """Location of the wscript file to use as the entry point"""
  58 top_dir = ''
  59 """Location of the project directory (top), if the project was configured"""
  60 out_dir = ''
  61 """Location of the build directory (out), if the project was configured"""
  62 waf_dir = ''
  63 """Directory containing the waf modules"""
  64
  65 default_encoding = Utils.console_encoding()
  66 """Encoding to use when reading outputs from other processes"""
  67
  68 g_module = None
  69 """
  70 Module representing the top-level wscript file (see :py:const:`waflib.Context.run_dir`)
  71 """
  72
  73 STDOUT = 1
  74 STDERR = -1
  75 BOTH   = 0
  76
  77 classes = []
  78 """
  79 List of :py:class:`waflib.Context.Context` subclasses that can be used as waf commands. The classes
  80 are added automatically by a metaclass.
  81 """
  82
  83 def create_context(cmd_name, *k, **kw):
  84         """
  85         Returns a new :py:class:`waflib.Context.Context` instance corresponding to the given command.
  86         Used in particular by :py:func:`waflib.Scripting.run_command`
  87
  88         :param cmd_name: command name
  89         :type cmd_name: string
  90         :param k: arguments to give to the context class initializer
  91         :type k: list
  92         :param k: keyword arguments to give to the context class initializer
  93         :type k: dict
  94         :return: Context object
  95         :rtype: :py:class:`waflib.Context.Context`
  96         """
  97         for x in classes:
  98                 if x.cmd == cmd_name:
  99                         return x(*k, **kw)
 100         ctx = Context(*k, **kw)
 101         ctx.fun = cmd_name
 102         return ctx
 103
 104 class store_context(type):
 105         """
 106         Metaclass that registers command classes into the list :py:const:`waflib.Context.classes`
 107         Context classes must provide an attribute 'cmd' representing the command name, and a function
 108         attribute 'fun' representing the function name that the command uses.
 109         """
 110         def __init__(cls, name, bases, dct):
 111                 super(store_context, cls).__init__(name, bases, dct)
 112                 name = cls.__name__
 113
 114                 if name in ('ctx', 'Context'):
 115                         return
 116
 117                 try:
 118                         cls.cmd
 119                 except AttributeError:
 120                         raise Errors.WafError('Missing command for the context class %r (cmd)' % name)
 121
 122                 if not getattr(cls, 'fun', None):
 123                         cls.fun = cls.cmd
 124
 125                 classes.insert(0, cls)
 126
 127 ctx = store_context('ctx', (object,), {})
 128 """Base class for all :py:class:`waflib.Context.Context` classes"""
 129
 130 class Context(ctx):
 131         """
 132         Default context for waf commands, and base class for new command contexts.
 133
 134         Context objects are passed to top-level functions::
 135
 136                 def foo(ctx):
 137                         print(ctx.__class__.__name__) # waflib.Context.Context
 138
 139         Subclasses must define the class attributes 'cmd' and 'fun':
 140
 141         :param cmd: command to execute as in ``waf cmd``
 142         :type cmd: string
 143         :param fun: function name to execute when the command is called
 144         :type fun: string
 145
 146         .. inheritance-diagram:: waflib.Context.Context waflib.Build.BuildContext waflib.Build.InstallContext waflib.Build.UninstallContext waflib.Build.StepContext waflib.Build.ListContext waflib.Configure.ConfigurationContext waflib.Scripting.Dist waflib.Scripting.DistCheck waflib.Build.CleanContext
 147            :top-classes: waflib.Context.Context
 148         """
 149
 150         errors = Errors
 151         """
 152         Shortcut to :py:mod:`waflib.Errors` provided for convenience
 153         """
 154
 155         tools = {}
 156         """
 157         A module cache for wscript files; see :py:meth:`Context.Context.load`
 158         """
 159
 160         def __init__(self, **kw):
 161                 try:
 162                         rd = kw['run_dir']
 163                 except KeyError:
 164                         rd = run_dir
 165
 166                 # binds the context to the nodes in use to avoid a context singleton
 167                 self.node_class = type('Nod3', (waflib.Node.Node,), {})
 168                 self.node_class.__module__ = 'waflib.Node'
 169                 self.node_class.ctx = self
 170
 171                 self.root = self.node_class('', None)
 172                 self.cur_script = None
 173                 self.path = self.root.find_dir(rd)
 174
 175                 self.stack_path = []
 176                 self.exec_dict = {'ctx':self, 'conf':self, 'bld':self, 'opt':self}
 177                 self.logger = None
 178
 179         def finalize(self):
 180                 """
 181                 Called to free resources such as logger files
 182                 """
 183                 try:
 184                         logger = self.logger
 185                 except AttributeError:
 186                         pass
 187                 else:
 188                         Logs.free_logger(logger)
 189                         delattr(self, 'logger')
 190
 191         def load(self, tool_list, *k, **kw):
 192                 """
 193                 Loads a Waf tool as a module, and try calling the function named :py:const:`waflib.Context.Context.fun`
 194                 from it.  A ``tooldir`` argument may be provided as a list of module paths.
 195
 196                 :param tool_list: list of Waf tool names to load
 197                 :type tool_list: list of string or space-separated string
 198                 """
 199                 tools = Utils.to_list(tool_list)
 200                 path = Utils.to_list(kw.get('tooldir', ''))
 201                 with_sys_path = kw.get('with_sys_path', True)
 202
 203                 for t in tools:
 204                         module = load_tool(t, path, with_sys_path=with_sys_path)
 205                         fun = getattr(module, kw.get('name', self.fun), None)
 206                         if fun:
 207                                 fun(self)
 208
 209         def execute(self):
 210                 """
 211                 Here, it calls the function name in the top-level wscript file. Most subclasses
 212                 redefine this method to provide additional functionality.
 213                 """
 214                 self.recurse([os.path.dirname(g_module.root_path)])
 215
 216         def pre_recurse(self, node):
 217                 """
 218                 Method executed immediately before a folder is read by :py:meth:`waflib.Context.Context.recurse`.
 219                 The current script is bound as a Node object on ``self.cur_script``, and the current path
 220                 is bound to ``self.path``
 221
 222                 :param node: script
 223                 :type node: :py:class:`waflib.Node.Node`
 224                 """
 225                 self.stack_path.append(self.cur_script)
 226
 227                 self.cur_script = node
 228                 self.path = node.parent
 229
 230         def post_recurse(self, node):
 231                 """
 232                 Restores ``self.cur_script`` and ``self.path`` right after :py:meth:`waflib.Context.Context.recurse` terminates.
 233
 234                 :param node: script
 235                 :type node: :py:class:`waflib.Node.Node`
 236                 """
 237                 self.cur_script = self.stack_path.pop()
 238                 if self.cur_script:
 239                         self.path = self.cur_script.parent
 240
 241         def recurse(self, dirs, name=None, mandatory=True, once=True, encoding=None):
 242                 """
 243                 Runs user-provided functions from the supplied list of directories.
 244                 The directories can be either absolute, or relative to the directory
 245                 of the wscript file
 246
 247                 The methods :py:meth:`waflib.Context.Context.pre_recurse` and
 248                 :py:meth:`waflib.Context.Context.post_recurse` are called immediately before
 249                 and after a script has been executed.
 250
 251                 :param dirs: List of directories to visit
 252                 :type dirs: list of string or space-separated string
 253                 :param name: Name of function to invoke from the wscript
 254                 :type  name: string
 255                 :param mandatory: whether sub wscript files are required to exist
 256                 :type  mandatory: bool
 257                 :param once: read the script file once for a particular context
 258                 :type once: bool
 259                 """
 260                 try:
 261                         cache = self.recurse_cache
 262                 except AttributeError:
 263                         cache = self.recurse_cache = {}
 264
 265                 for d in Utils.to_list(dirs):
 266
 267                         if not os.path.isabs(d):
 268                                 # absolute paths only
 269                                 d = os.path.join(self.path.abspath(), d)
 270
 271                         WSCRIPT     = os.path.join(d, WSCRIPT_FILE)
 272                         WSCRIPT_FUN = WSCRIPT + '_' + (name or self.fun)
 273
 274                         node = self.root.find_node(WSCRIPT_FUN)
 275                         if node and (not once or node not in cache):
 276                                 cache[node] = True
 277                                 self.pre_recurse(node)
 278                                 try:
 279                                         function_code = node.read('r', encoding)
 280                                         exec(compile(function_code, node.abspath(), 'exec'), self.exec_dict)
 281                                 finally:
 282                                         self.post_recurse(node)
 283                         elif not node:
 284                                 node = self.root.find_node(WSCRIPT)
 285                                 tup = (node, name or self.fun)
 286                                 if node and (not once or tup not in cache):
 287                                         cache[tup] = True
 288                                         self.pre_recurse(node)
 289                                         try:
 290                                                 wscript_module = load_module(node.abspath(), encoding=encoding)
 291                                                 user_function = getattr(wscript_module, (name or self.fun), None)
 292                                                 if not user_function:
 293                                                         if not mandatory:
 294                                                                 continue
 295                                                         raise Errors.WafError('No function %r defined in %s' % (name or self.fun, node.abspath()))
 296                                                 user_function(self)
 297                                         finally:
 298                                                 self.post_recurse(node)
 299                                 elif not node:
 300                                         if not mandatory:
 301                                                 continue
 302                                         try:
 303                                                 os.listdir(d)
 304                                         except OSError:
 305                                                 raise Errors.WafError('Cannot read the folder %r' % d)
 306                                         raise Errors.WafError('No wscript file in directory %s' % d)
 307
 308         def log_command(self, cmd, kw):
 309                 if Logs.verbose:
 310                         fmt = os.environ.get('WAF_CMD_FORMAT')
 311                         if fmt == 'string':
 312                                 if not isinstance(cmd, str):
 313                                         cmd = Utils.shell_escape(cmd)
 314                         Logs.debug('runner: %r', cmd)
 315                         Logs.debug('runner_env: kw=%s', kw)
 316
 317         def exec_command(self, cmd, **kw):
 318                 """
 319                 Runs an external process and returns the exit status::
 320
 321                         def run(tsk):
 322                                 ret = tsk.generator.bld.exec_command('touch foo.txt')
 323                                 return ret
 324
 325                 If the context has the attribute 'log', then captures and logs the process stderr/stdout.
 326                 Unlike :py:meth:`waflib.Context.Context.cmd_and_log`, this method does not return the
 327                 stdout/stderr values captured.
 328
 329                 :param cmd: command argument for subprocess.Popen
 330                 :type cmd: string or list
 331                 :param kw: keyword arguments for subprocess.Popen. The parameters input/timeout will be passed to wait/communicate.
 332                 :type kw: dict
 333                 :returns: process exit status
 334                 :rtype: integer
 335                 :raises: :py:class:`waflib.Errors.WafError` if an invalid executable is specified for a non-shell process
 336                 :raises: :py:class:`waflib.Errors.WafError` in case of execution failure
 337                 """
 338                 subprocess = Utils.subprocess
 339                 kw['shell'] = isinstance(cmd, str)
 340                 self.log_command(cmd, kw)
 341
 342                 if self.logger:
 343                         self.logger.info(cmd)
 344
 345                 if 'stdout' not in kw:
 346                         kw['stdout'] = subprocess.PIPE
 347                 if 'stderr' not in kw:
 348                         kw['stderr'] = subprocess.PIPE
 349
 350                 if Logs.verbose and not kw['shell'] and not Utils.check_exe(cmd[0]):
 351                         raise Errors.WafError('Program %s not found!' % cmd[0])
 352
 353                 cargs = {}
 354                 if 'timeout' in kw:
 355                         if sys.hexversion >= 0x3030000:
 356                                 cargs['timeout'] = kw['timeout']
 357                                 if not 'start_new_session' in kw:
 358                                         kw['start_new_session'] = True
 359                         del kw['timeout']
 360                 if 'input' in kw:
 361                         if kw['input']:
 362                                 cargs['input'] = kw['input']
 363                                 kw['stdin'] = subprocess.PIPE
 364                         del kw['input']
 365
 366                 if 'cwd' in kw:
 367                         if not isinstance(kw['cwd'], str):
 368                                 kw['cwd'] = kw['cwd'].abspath()
 369
 370                 encoding = kw.pop('decode_as', default_encoding)
 371
 372                 try:
 373                         ret, out, err = Utils.run_process(cmd, kw, cargs)
 374                 except Exception as e:
 375                         raise Errors.WafError('Execution failure: %s' % str(e), ex=e)
 376
 377                 if out:
 378                         if not isinstance(out, str):
 379                                 out = out.decode(encoding, errors='replace')
 380                         if self.logger:
 381                                 self.logger.debug('out: %s', out)
 382                         else:
 383                                 Logs.info(out, extra={'stream':sys.stdout, 'c1': ''})
 384                 if err:
 385                         if not isinstance(err, str):
 386                                 err = err.decode(encoding, errors='replace')
 387                         if self.logger:
 388                                 self.logger.error('err: %s' % err)
 389                         else:
 390                                 Logs.info(err, extra={'stream':sys.stderr, 'c1': ''})
 391
 392                 return ret
 393
 394         def cmd_and_log(self, cmd, **kw):
 395                 """
 396                 Executes a process and returns stdout/stderr if the execution is successful.
 397                 An exception is thrown when the exit status is non-0. In that case, both stderr and stdout
 398                 will be bound to the WafError object (configuration tests)::
 399
 400                         def configure(conf):
 401                                 out = conf.cmd_and_log(['echo', 'hello'], output=waflib.Context.STDOUT, quiet=waflib.Context.BOTH)
 402                                 (out, err) = conf.cmd_and_log(['echo', 'hello'], output=waflib.Context.BOTH)
 403                                 (out, err) = conf.cmd_and_log(cmd, input='\\n'.encode(), output=waflib.Context.STDOUT)
 404                                 try:
 405                                         conf.cmd_and_log(['which', 'someapp'], output=waflib.Context.BOTH)
 406                                 except Errors.WafError as e:
 407                                         print(e.stdout, e.stderr)
 408
 409                 :param cmd: args for subprocess.Popen
 410                 :type cmd: list or string
 411                 :param kw: keyword arguments for subprocess.Popen. The parameters input/timeout will be passed to wait/communicate.
 412                 :type kw: dict
 413                 :returns: a tuple containing the contents of stdout and stderr
 414                 :rtype: string
 415                 :raises: :py:class:`waflib.Errors.WafError` if an invalid executable is specified for a non-shell process
 416                 :raises: :py:class:`waflib.Errors.WafError` in case of execution failure; stdout/stderr/returncode are bound to the exception object
 417                 """
 418                 subprocess = Utils.subprocess
 419                 kw['shell'] = isinstance(cmd, str)
 420                 self.log_command(cmd, kw)
 421
 422                 quiet = kw.pop('quiet', None)
 423                 to_ret = kw.pop('output', STDOUT)
 424
 425                 if Logs.verbose and not kw['shell'] and not Utils.check_exe(cmd[0]):
 426                         raise Errors.WafError('Program %r not found!' % cmd[0])
 427
 428                 kw['stdout'] = kw['stderr'] = subprocess.PIPE
 429                 if quiet is None:
 430                         self.to_log(cmd)
 431
 432                 cargs = {}
 433                 if 'timeout' in kw:
 434                         if sys.hexversion >= 0x3030000:
 435                                 cargs['timeout'] = kw['timeout']
 436                                 if not 'start_new_session' in kw:
 437                                         kw['start_new_session'] = True
 438                         del kw['timeout']
 439                 if 'input' in kw:
 440                         if kw['input']:
 441                                 cargs['input'] = kw['input']
 442                                 kw['stdin'] = subprocess.PIPE
 443                         del kw['input']
 444
 445                 if 'cwd' in kw:
 446                         if not isinstance(kw['cwd'], str):
 447                                 kw['cwd'] = kw['cwd'].abspath()
 448
 449                 encoding = kw.pop('decode_as', default_encoding)
 450
 451                 try:
 452                         ret, out, err = Utils.run_process(cmd, kw, cargs)
 453                 except Exception as e:
 454                         raise Errors.WafError('Execution failure: %s' % str(e), ex=e)
 455
 456                 if not isinstance(out, str):
 457                         out = out.decode(encoding, errors='replace')
 458                 if not isinstance(err, str):
 459                         err = err.decode(encoding, errors='replace')
 460
 461                 if out and quiet != STDOUT and quiet != BOTH:
 462                         self.to_log('out: %s' % out)
 463                 if err and quiet != STDERR and quiet != BOTH:
 464                         self.to_log('err: %s' % err)
 465
 466                 if ret:
 467                         e = Errors.WafError('Command %r returned %r' % (cmd, ret))
 468                         e.returncode = ret
 469                         e.stderr = err
 470                         e.stdout = out
 471                         raise e
 472
 473                 if to_ret == BOTH:
 474                         return (out, err)
 475                 elif to_ret == STDERR:
 476                         return err
 477                 return out
 478
 479         def fatal(self, msg, ex=None):
 480                 """
 481                 Prints an error message in red and stops command execution; this is
 482                 usually used in the configuration section::
 483
 484                         def configure(conf):
 485                                 conf.fatal('a requirement is missing')
 486
 487                 :param msg: message to display
 488                 :type msg: string
 489                 :param ex: optional exception object
 490                 :type ex: exception
 491                 :raises: :py:class:`waflib.Errors.ConfigurationError`
 492                 """
 493                 if self.logger:
 494                         self.logger.info('from %s: %s' % (self.path.abspath(), msg))
 495                 try:
 496                         logfile = self.logger.handlers[0].baseFilename
 497                 except AttributeError:
 498                         pass
 499                 else:
 500                         if os.environ.get('WAF_PRINT_FAILURE_LOG'):
 501                                 # see #1930
 502                                 msg = 'Log from (%s):\n%s\n' % (logfile, Utils.readf(logfile))
 503                         else:
 504                                 msg = '%s\n(complete log in %s)' % (msg, logfile)
 505                 raise self.errors.ConfigurationError(msg, ex=ex)
 506
 507         def to_log(self, msg):
 508                 """
 509                 Logs information to the logger (if present), or to stderr.
 510                 Empty messages are not printed::
 511
 512                         def build(bld):
 513                                 bld.to_log('starting the build')
 514
 515                 Provide a logger on the context class or override this method if necessary.
 516
 517                 :param msg: message
 518                 :type msg: string
 519                 """
 520                 if not msg:
 521                         return
 522                 if self.logger:
 523                         self.logger.info(msg)
 524                 else:
 525                         sys.stderr.write(str(msg))
 526                         sys.stderr.flush()
 527
 528
 529         def msg(self, *k, **kw):
 530                 """
 531                 Prints a configuration message of the form ``msg: result``.
 532                 The second part of the message will be in colors. The output
 533                 can be disabled easily by setting ``in_msg`` to a positive value::
 534
 535                         def configure(conf):
 536                                 self.in_msg = 1
 537                                 conf.msg('Checking for library foo', 'ok')
 538                                 # no output
 539
 540                 :param msg: message to display to the user
 541                 :type msg: string
 542                 :param result: result to display
 543                 :type result: string or boolean
 544                 :param color: color to use, see :py:const:`waflib.Logs.colors_lst`
 545                 :type color: string
 546                 """
 547                 try:
 548                         msg = kw['msg']
 549                 except KeyError:
 550                         msg = k[0]
 551
 552                 self.start_msg(msg, **kw)
 553
 554                 try:
 555                         result = kw['result']
 556                 except KeyError:
 557                         result = k[1]
 558
 559                 color = kw.get('color')
 560                 if not isinstance(color, str):
 561                         color = result and 'GREEN' or 'YELLOW'
 562
 563                 self.end_msg(result, color, **kw)
 564
 565         def start_msg(self, *k, **kw):
 566                 """
 567                 Prints the beginning of a 'Checking for xxx' message. See :py:meth:`waflib.Context.Context.msg`
 568                 """
 569                 if kw.get('quiet'):
 570                         return
 571
 572                 msg = kw.get('msg') or k[0]
 573                 try:
 574                         if self.in_msg:
 575                                 self.in_msg += 1
 576                                 return
 577                 except AttributeError:
 578                         self.in_msg = 0
 579                 self.in_msg += 1
 580
 581                 try:
 582                         self.line_just = max(self.line_just, len(msg))
 583                 except AttributeError:
 584                         self.line_just = max(40, len(msg))
 585                 for x in (self.line_just * '-', msg):
 586                         self.to_log(x)
 587                 Logs.pprint('NORMAL', "%s :" % msg.ljust(self.line_just), sep='')
 588
 589         def end_msg(self, *k, **kw):
 590                 """Prints the end of a 'Checking for' message. See :py:meth:`waflib.Context.Context.msg`"""
 591                 if kw.get('quiet'):
 592                         return
 593                 self.in_msg -= 1
 594                 if self.in_msg:
 595                         return
 596
 597                 result = kw.get('result') or k[0]
 598
 599                 defcolor = 'GREEN'
 600                 if result is True:
 601                         msg = 'ok'
 602                 elif not result:
 603                         msg = 'not found'
 604                         defcolor = 'YELLOW'
 605                 else:
 606                         msg = str(result)
 607
 608                 self.to_log(msg)
 609                 try:
 610                         color = kw['color']
 611                 except KeyError:
 612                         if len(k) > 1 and k[1] in Logs.colors_lst:
 613                                 # compatibility waf 1.7
 614                                 color = k[1]
 615                         else:
 616                                 color = defcolor
 617                 Logs.pprint(color, msg)
 618
 619         def load_special_tools(self, var, ban=[]):
 620                 """
 621                 Loads third-party extensions modules for certain programming languages
 622                 by trying to list certain files in the extras/ directory. This method
 623                 is typically called once for a programming language group, see for
 624                 example :py:mod:`waflib.Tools.compiler_c`
 625
 626                 :param var: glob expression, for example 'cxx\\_\\*.py'
 627                 :type var: string
 628                 :param ban: list of exact file names to exclude
 629                 :type ban: list of string
 630                 """
 631                 if os.path.isdir(waf_dir):
 632                         lst = self.root.find_node(waf_dir).find_node('waflib/extras').ant_glob(var)
 633                         for x in lst:
 634                                 if not x.name in ban:
 635                                         load_tool(x.name.replace('.py', ''))
 636                 else:
 637                         from zipfile import PyZipFile
 638                         waflibs = PyZipFile(waf_dir)
 639                         lst = waflibs.namelist()
 640                         for x in lst:
 641                                 if not re.match('waflib/extras/%s' % var.replace('*', '.*'), var):
 642                                         continue
 643                                 f = os.path.basename(x)
 644                                 doban = False
 645                                 for b in ban:
 646                                         r = b.replace('*', '.*')
 647                                         if re.match(r, f):
 648                                                 doban = True
 649                                 if not doban:
 650                                         f = f.replace('.py', '')
 651                                         load_tool(f)
 652
 653 cache_modules = {}
 654 """
 655 Dictionary holding already loaded modules (wscript), indexed by their absolute path.
 656 The modules are added automatically by :py:func:`waflib.Context.load_module`
 657 """
 658
 659 def load_module(path, encoding=None):
 660         """
 661         Loads a wscript file as a python module. This method caches results in :py:attr:`waflib.Context.cache_modules`
 662
 663         :param path: file path
 664         :type path: string
 665         :return: Loaded Python module
 666         :rtype: module
 667         """
 668         try:
 669                 return cache_modules[path]
 670         except KeyError:
 671                 pass
 672
 673         module = imp.new_module(WSCRIPT_FILE)
 674         try:
 675                 code = Utils.readf(path, m='r', encoding=encoding)
 676         except EnvironmentError:
 677                 raise Errors.WafError('Could not read the file %r' % path)
 678
 679         module_dir = os.path.dirname(path)
 680         sys.path.insert(0, module_dir)
 681         try:
 682                 exec(compile(code, path, 'exec'), module.__dict__)
 683         finally:
 684                 sys.path.remove(module_dir)
 685
 686         cache_modules[path] = module
 687         return module
 688
 689 def load_tool(tool, tooldir=None, ctx=None, with_sys_path=True):
 690         """
 691         Imports a Waf tool as a python module, and stores it in the dict :py:const:`waflib.Context.Context.tools`
 692
 693         :type  tool: string
 694         :param tool: Name of the tool
 695         :type  tooldir: list
 696         :param tooldir: List of directories to search for the tool module
 697         :type  with_sys_path: boolean
 698         :param with_sys_path: whether or not to search the regular sys.path, besides waf_dir and potentially given tooldirs
 699         """
 700         if tool == 'java':
 701                 tool = 'javaw' # jython
 702         else:
 703                 tool = tool.replace('++', 'xx')
 704
 705         if not with_sys_path:
 706                 back_path = sys.path
 707                 sys.path = []
 708         try:
 709                 if tooldir:
 710                         assert isinstance(tooldir, list)
 711                         sys.path = tooldir + sys.path
 712                         try:
 713                                 __import__(tool)
 714                         except ImportError as e:
 715                                 e.waf_sys_path = list(sys.path)
 716                                 raise
 717                         finally:
 718                                 for d in tooldir:
 719                                         sys.path.remove(d)
 720                         ret = sys.modules[tool]
 721                         Context.tools[tool] = ret
 722                         return ret
 723                 else:
 724                         if not with_sys_path:
 725                                 sys.path.insert(0, waf_dir)
 726                         try:
 727                                 for x in ('waflib.Tools.%s', 'waflib.extras.%s', 'waflib.%s', '%s'):
 728                                         try:
 729                                                 __import__(x % tool)
 730                                                 break
 731                                         except ImportError:
 732                                                 x = None
 733                                 else: # raise an exception
 734                                         __import__(tool)
 735                         except ImportError as e:
 736                                 e.waf_sys_path = list(sys.path)
 737                                 raise
 738                         finally:
 739                                 if not with_sys_path:
 740                                         sys.path.remove(waf_dir)
 741                         ret = sys.modules[x % tool]
 742                         Context.tools[tool] = ret
 743                         return ret
 744         finally:
 745                 if not with_sys_path:
 746                         sys.path += back_path
 747