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| 1 # -*- coding: utf-8 -*- | |
| 2 """ | |
| 3 jinja2.runtime | |
| 4 ~~~~~~~~~~~~~~ | |
| 5 | |
| 6 Runtime helpers. | |
| 7 | |
| 8 :copyright: (c) 2010 by the Jinja Team. | |
| 9 :license: BSD. | |
| 10 """ | |
| 11 from itertools import chain | |
| 12 from jinja2.nodes import EvalContext, _context_function_types | |
| 13 from jinja2.utils import Markup, soft_unicode, escape, missing, concat, \ | |
| 14 internalcode, object_type_repr | |
| 15 from jinja2.exceptions import UndefinedError, TemplateRuntimeError, \ | |
| 16 TemplateNotFound | |
| 17 from jinja2._compat import next, imap, text_type, iteritems, \ | |
| 18 implements_iterator, implements_to_string, string_types, PY2 | |
| 19 | |
| 20 | |
| 21 # these variables are exported to the template runtime | |
| 22 __all__ = ['LoopContext', 'TemplateReference', 'Macro', 'Markup', | |
| 23 'TemplateRuntimeError', 'missing', 'concat', 'escape', | |
| 24 'markup_join', 'unicode_join', 'to_string', 'identity', | |
| 25 'TemplateNotFound'] | |
| 26 | |
| 27 #: the name of the function that is used to convert something into | |
| 28 #: a string. We can just use the text type here. | |
| 29 to_string = text_type | |
| 30 | |
| 31 #: the identity function. Useful for certain things in the environment | |
| 32 identity = lambda x: x | |
| 33 | |
| 34 _last_iteration = object() | |
| 35 | |
| 36 | |
| 37 def markup_join(seq): | |
| 38 """Concatenation that escapes if necessary and converts to unicode.""" | |
| 39 buf = [] | |
| 40 iterator = imap(soft_unicode, seq) | |
| 41 for arg in iterator: | |
| 42 buf.append(arg) | |
| 43 if hasattr(arg, '__html__'): | |
| 44 return Markup(u'').join(chain(buf, iterator)) | |
| 45 return concat(buf) | |
| 46 | |
| 47 | |
| 48 def unicode_join(seq): | |
| 49 """Simple args to unicode conversion and concatenation.""" | |
| 50 return concat(imap(text_type, seq)) | |
| 51 | |
| 52 | |
| 53 def new_context(environment, template_name, blocks, vars=None, | |
| 54 shared=None, globals=None, locals=None): | |
| 55 """Internal helper to for context creation.""" | |
| 56 if vars is None: | |
| 57 vars = {} | |
| 58 if shared: | |
| 59 parent = vars | |
| 60 else: | |
| 61 parent = dict(globals or (), **vars) | |
| 62 if locals: | |
| 63 # if the parent is shared a copy should be created because | |
| 64 # we don't want to modify the dict passed | |
| 65 if shared: | |
| 66 parent = dict(parent) | |
| 67 for key, value in iteritems(locals): | |
| 68 if key[:2] == 'l_' and value is not missing: | |
| 69 parent[key[2:]] = value | |
| 70 return Context(environment, parent, template_name, blocks) | |
| 71 | |
| 72 | |
| 73 class TemplateReference(object): | |
| 74 """The `self` in templates.""" | |
| 75 | |
| 76 def __init__(self, context): | |
| 77 self.__context = context | |
| 78 | |
| 79 def __getitem__(self, name): | |
| 80 blocks = self.__context.blocks[name] | |
| 81 return BlockReference(name, self.__context, blocks, 0) | |
| 82 | |
| 83 def __repr__(self): | |
| 84 return '<%s %r>' % ( | |
| 85 self.__class__.__name__, | |
| 86 self.__context.name | |
| 87 ) | |
| 88 | |
| 89 | |
| 90 class Context(object): | |
| 91 """The template context holds the variables of a template. It stores the | |
| 92 values passed to the template and also the names the template exports. | |
| 93 Creating instances is neither supported nor useful as it's created | |
| 94 automatically at various stages of the template evaluation and should not | |
| 95 be created by hand. | |
| 96 | |
| 97 The context is immutable. Modifications on :attr:`parent` **must not** | |
| 98 happen and modifications on :attr:`vars` are allowed from generated | |
| 99 template code only. Template filters and global functions marked as | |
| 100 :func:`contextfunction`\s get the active context passed as first argument | |
| 101 and are allowed to access the context read-only. | |
| 102 | |
| 103 The template context supports read only dict operations (`get`, | |
| 104 `keys`, `values`, `items`, `iterkeys`, `itervalues`, `iteritems`, | |
| 105 `__getitem__`, `__contains__`). Additionally there is a :meth:`resolve` | |
| 106 method that doesn't fail with a `KeyError` but returns an | |
| 107 :class:`Undefined` object for missing variables. | |
| 108 """ | |
| 109 __slots__ = ('parent', 'vars', 'environment', 'eval_ctx', 'exported_vars', | |
| 110 'name', 'blocks', '__weakref__') | |
| 111 | |
| 112 def __init__(self, environment, parent, name, blocks): | |
| 113 self.parent = parent | |
| 114 self.vars = {} | |
| 115 self.environment = environment | |
| 116 self.eval_ctx = EvalContext(self.environment, name) | |
| 117 self.exported_vars = set() | |
| 118 self.name = name | |
| 119 | |
| 120 # create the initial mapping of blocks. Whenever template inheritance | |
| 121 # takes place the runtime will update this mapping with the new blocks | |
| 122 # from the template. | |
| 123 self.blocks = dict((k, [v]) for k, v in iteritems(blocks)) | |
| 124 | |
| 125 def super(self, name, current): | |
| 126 """Render a parent block.""" | |
| 127 try: | |
| 128 blocks = self.blocks[name] | |
| 129 index = blocks.index(current) + 1 | |
| 130 blocks[index] | |
| 131 except LookupError: | |
| 132 return self.environment.undefined('there is no parent block ' | |
| 133 'called %r.' % name, | |
| 134 name='super') | |
| 135 return BlockReference(name, self, blocks, index) | |
| 136 | |
| 137 def get(self, key, default=None): | |
| 138 """Returns an item from the template context, if it doesn't exist | |
| 139 `default` is returned. | |
| 140 """ | |
| 141 try: | |
| 142 return self[key] | |
| 143 except KeyError: | |
| 144 return default | |
| 145 | |
| 146 def resolve(self, key): | |
| 147 """Looks up a variable like `__getitem__` or `get` but returns an | |
| 148 :class:`Undefined` object with the name of the name looked up. | |
| 149 """ | |
| 150 if key in self.vars: | |
| 151 return self.vars[key] | |
| 152 if key in self.parent: | |
| 153 return self.parent[key] | |
| 154 return self.environment.undefined(name=key) | |
| 155 | |
| 156 def get_exported(self): | |
| 157 """Get a new dict with the exported variables.""" | |
| 158 return dict((k, self.vars[k]) for k in self.exported_vars) | |
| 159 | |
| 160 def get_all(self): | |
| 161 """Return a copy of the complete context as dict including the | |
| 162 exported variables. | |
| 163 """ | |
| 164 return dict(self.parent, **self.vars) | |
| 165 | |
| 166 @internalcode | |
| 167 def call(__self, __obj, *args, **kwargs): | |
| 168 """Call the callable with the arguments and keyword arguments | |
| 169 provided but inject the active context or environment as first | |
| 170 argument if the callable is a :func:`contextfunction` or | |
| 171 :func:`environmentfunction`. | |
| 172 """ | |
| 173 if __debug__: | |
| 174 __traceback_hide__ = True | |
| 175 | |
| 176 # Allow callable classes to take a context | |
| 177 fn = __obj.__call__ | |
| 178 for fn_type in ('contextfunction', | |
| 179 'evalcontextfunction', | |
| 180 'environmentfunction'): | |
| 181 if hasattr(fn, fn_type): | |
| 182 __obj = fn | |
| 183 break | |
| 184 | |
| 185 if isinstance(__obj, _context_function_types): | |
| 186 if getattr(__obj, 'contextfunction', 0): | |
| 187 args = (__self,) + args | |
| 188 elif getattr(__obj, 'evalcontextfunction', 0): | |
| 189 args = (__self.eval_ctx,) + args | |
| 190 elif getattr(__obj, 'environmentfunction', 0): | |
| 191 args = (__self.environment,) + args | |
| 192 try: | |
| 193 return __obj(*args, **kwargs) | |
| 194 except StopIteration: | |
| 195 return __self.environment.undefined('value was undefined because ' | |
| 196 'a callable raised a ' | |
| 197 'StopIteration exception') | |
| 198 | |
| 199 def derived(self, locals=None): | |
| 200 """Internal helper function to create a derived context.""" | |
| 201 context = new_context(self.environment, self.name, {}, | |
| 202 self.parent, True, None, locals) | |
| 203 context.vars.update(self.vars) | |
| 204 context.eval_ctx = self.eval_ctx | |
| 205 context.blocks.update((k, list(v)) for k, v in iteritems(self.blocks)) | |
| 206 return context | |
| 207 | |
| 208 def _all(meth): | |
| 209 proxy = lambda self: getattr(self.get_all(), meth)() | |
| 210 proxy.__doc__ = getattr(dict, meth).__doc__ | |
| 211 proxy.__name__ = meth | |
| 212 return proxy | |
| 213 | |
| 214 keys = _all('keys') | |
| 215 values = _all('values') | |
| 216 items = _all('items') | |
| 217 | |
| 218 # not available on python 3 | |
| 219 if PY2: | |
| 220 iterkeys = _all('iterkeys') | |
| 221 itervalues = _all('itervalues') | |
| 222 iteritems = _all('iteritems') | |
| 223 del _all | |
| 224 | |
| 225 def __contains__(self, name): | |
| 226 return name in self.vars or name in self.parent | |
| 227 | |
| 228 def __getitem__(self, key): | |
| 229 """Lookup a variable or raise `KeyError` if the variable is | |
| 230 undefined. | |
| 231 """ | |
| 232 item = self.resolve(key) | |
| 233 if isinstance(item, Undefined): | |
| 234 raise KeyError(key) | |
| 235 return item | |
| 236 | |
| 237 def __repr__(self): | |
| 238 return '<%s %s of %r>' % ( | |
| 239 self.__class__.__name__, | |
| 240 repr(self.get_all()), | |
| 241 self.name | |
| 242 ) | |
| 243 | |
| 244 | |
| 245 # register the context as mapping if possible | |
| 246 try: | |
| 247 from collections import Mapping | |
| 248 Mapping.register(Context) | |
| 249 except ImportError: | |
| 250 pass | |
| 251 | |
| 252 | |
| 253 class BlockReference(object): | |
| 254 """One block on a template reference.""" | |
| 255 | |
| 256 def __init__(self, name, context, stack, depth): | |
| 257 self.name = name | |
| 258 self._context = context | |
| 259 self._stack = stack | |
| 260 self._depth = depth | |
| 261 | |
| 262 @property | |
| 263 def super(self): | |
| 264 """Super the block.""" | |
| 265 if self._depth + 1 >= len(self._stack): | |
| 266 return self._context.environment. \ | |
| 267 undefined('there is no parent block called %r.' % | |
| 268 self.name, name='super') | |
| 269 return BlockReference(self.name, self._context, self._stack, | |
| 270 self._depth + 1) | |
| 271 | |
| 272 @internalcode | |
| 273 def __call__(self): | |
| 274 rv = concat(self._stack[self._depth](self._context)) | |
| 275 if self._context.eval_ctx.autoescape: | |
| 276 rv = Markup(rv) | |
| 277 return rv | |
| 278 | |
| 279 | |
| 280 class LoopContext(object): | |
| 281 """A loop context for dynamic iteration.""" | |
| 282 | |
| 283 def __init__(self, iterable, recurse=None, depth0=0): | |
| 284 self._iterator = iter(iterable) | |
| 285 self._recurse = recurse | |
| 286 self._after = self._safe_next() | |
| 287 self.index0 = -1 | |
| 288 self.depth0 = depth0 | |
| 289 | |
| 290 # try to get the length of the iterable early. This must be done | |
| 291 # here because there are some broken iterators around where there | |
| 292 # __len__ is the number of iterations left (i'm looking at your | |
| 293 # listreverseiterator!). | |
| 294 try: | |
| 295 self._length = len(iterable) | |
| 296 except (TypeError, AttributeError): | |
| 297 self._length = None | |
| 298 | |
| 299 def cycle(self, *args): | |
| 300 """Cycles among the arguments with the current loop index.""" | |
| 301 if not args: | |
| 302 raise TypeError('no items for cycling given') | |
| 303 return args[self.index0 % len(args)] | |
| 304 | |
| 305 first = property(lambda x: x.index0 == 0) | |
| 306 last = property(lambda x: x._after is _last_iteration) | |
| 307 index = property(lambda x: x.index0 + 1) | |
| 308 revindex = property(lambda x: x.length - x.index0) | |
| 309 revindex0 = property(lambda x: x.length - x.index) | |
| 310 depth = property(lambda x: x.depth0 + 1) | |
| 311 | |
| 312 def __len__(self): | |
| 313 return self.length | |
| 314 | |
| 315 def __iter__(self): | |
| 316 return LoopContextIterator(self) | |
| 317 | |
| 318 def _safe_next(self): | |
| 319 try: | |
| 320 return next(self._iterator) | |
| 321 except StopIteration: | |
| 322 return _last_iteration | |
| 323 | |
| 324 @internalcode | |
| 325 def loop(self, iterable): | |
| 326 if self._recurse is None: | |
| 327 raise TypeError('Tried to call non recursive loop. Maybe you ' | |
| 328 "forgot the 'recursive' modifier.") | |
| 329 return self._recurse(iterable, self._recurse, self.depth0 + 1) | |
| 330 | |
| 331 # a nifty trick to enhance the error message if someone tried to call | |
| 332 # the the loop without or with too many arguments. | |
| 333 __call__ = loop | |
| 334 del loop | |
| 335 | |
| 336 @property | |
| 337 def length(self): | |
| 338 if self._length is None: | |
| 339 # if was not possible to get the length of the iterator when | |
| 340 # the loop context was created (ie: iterating over a generator) | |
| 341 # we have to convert the iterable into a sequence and use the | |
| 342 # length of that. | |
| 343 iterable = tuple(self._iterator) | |
| 344 self._iterator = iter(iterable) | |
| 345 self._length = len(iterable) + self.index0 + 1 | |
| 346 return self._length | |
| 347 | |
| 348 def __repr__(self): | |
| 349 return '<%s %r/%r>' % ( | |
| 350 self.__class__.__name__, | |
| 351 self.index, | |
| 352 self.length | |
| 353 ) | |
| 354 | |
| 355 | |
| 356 @implements_iterator | |
| 357 class LoopContextIterator(object): | |
| 358 """The iterator for a loop context.""" | |
| 359 __slots__ = ('context',) | |
| 360 | |
| 361 def __init__(self, context): | |
| 362 self.context = context | |
| 363 | |
| 364 def __iter__(self): | |
| 365 return self | |
| 366 | |
| 367 def __next__(self): | |
| 368 ctx = self.context | |
| 369 ctx.index0 += 1 | |
| 370 if ctx._after is _last_iteration: | |
| 371 raise StopIteration() | |
| 372 next_elem = ctx._after | |
| 373 ctx._after = ctx._safe_next() | |
| 374 return next_elem, ctx | |
| 375 | |
| 376 | |
| 377 class Macro(object): | |
| 378 """Wraps a macro function.""" | |
| 379 | |
| 380 def __init__(self, environment, func, name, arguments, defaults, | |
| 381 catch_kwargs, catch_varargs, caller): | |
| 382 self._environment = environment | |
| 383 self._func = func | |
| 384 self._argument_count = len(arguments) | |
| 385 self.name = name | |
| 386 self.arguments = arguments | |
| 387 self.defaults = defaults | |
| 388 self.catch_kwargs = catch_kwargs | |
| 389 self.catch_varargs = catch_varargs | |
| 390 self.caller = caller | |
| 391 | |
| 392 @internalcode | |
| 393 def __call__(self, *args, **kwargs): | |
| 394 # try to consume the positional arguments | |
| 395 arguments = list(args[:self._argument_count]) | |
| 396 off = len(arguments) | |
| 397 | |
| 398 # if the number of arguments consumed is not the number of | |
| 399 # arguments expected we start filling in keyword arguments | |
| 400 # and defaults. | |
| 401 if off != self._argument_count: | |
| 402 for idx, name in enumerate(self.arguments[len(arguments):]): | |
| 403 try: | |
| 404 value = kwargs.pop(name) | |
| 405 except KeyError: | |
| 406 try: | |
| 407 value = self.defaults[idx - self._argument_count + off] | |
| 408 except IndexError: | |
| 409 value = self._environment.undefined( | |
| 410 'parameter %r was not provided' % name, name=name) | |
| 411 arguments.append(value) | |
| 412 | |
| 413 # it's important that the order of these arguments does not change | |
| 414 # if not also changed in the compiler's `function_scoping` method. | |
| 415 # the order is caller, keyword arguments, positional arguments! | |
| 416 if self.caller: | |
| 417 caller = kwargs.pop('caller', None) | |
| 418 if caller is None: | |
| 419 caller = self._environment.undefined('No caller defined', | |
| 420 name='caller') | |
| 421 arguments.append(caller) | |
| 422 if self.catch_kwargs: | |
| 423 arguments.append(kwargs) | |
| 424 elif kwargs: | |
| 425 raise TypeError('macro %r takes no keyword argument %r' % | |
| 426 (self.name, next(iter(kwargs)))) | |
| 427 if self.catch_varargs: | |
| 428 arguments.append(args[self._argument_count:]) | |
| 429 elif len(args) > self._argument_count: | |
| 430 raise TypeError('macro %r takes not more than %d argument(s)' % | |
| 431 (self.name, len(self.arguments))) | |
| 432 return self._func(*arguments) | |
| 433 | |
| 434 def __repr__(self): | |
| 435 return '<%s %s>' % ( | |
| 436 self.__class__.__name__, | |
| 437 self.name is None and 'anonymous' or repr(self.name) | |
| 438 ) | |
| 439 | |
| 440 | |
| 441 @implements_to_string | |
| 442 class Undefined(object): | |
| 443 """The default undefined type. This undefined type can be printed and | |
| 444 iterated over, but every other access will raise an :exc:`UndefinedError`: | |
| 445 | |
| 446 >>> foo = Undefined(name='foo') | |
| 447 >>> str(foo) | |
| 448 '' | |
| 449 >>> not foo | |
| 450 True | |
| 451 >>> foo + 42 | |
| 452 Traceback (most recent call last): | |
| 453 ... | |
| 454 UndefinedError: 'foo' is undefined | |
| 455 """ | |
| 456 __slots__ = ('_undefined_hint', '_undefined_obj', '_undefined_name', | |
| 457 '_undefined_exception') | |
| 458 | |
| 459 def __init__(self, hint=None, obj=missing, name=None, exc=UndefinedError): | |
| 460 self._undefined_hint = hint | |
| 461 self._undefined_obj = obj | |
| 462 self._undefined_name = name | |
| 463 self._undefined_exception = exc | |
| 464 | |
| 465 @internalcode | |
| 466 def _fail_with_undefined_error(self, *args, **kwargs): | |
| 467 """Regular callback function for undefined objects that raises an | |
| 468 `UndefinedError` on call. | |
| 469 """ | |
| 470 if self._undefined_hint is None: | |
| 471 if self._undefined_obj is missing: | |
| 472 hint = '%r is undefined' % self._undefined_name | |
| 473 elif not isinstance(self._undefined_name, string_types): | |
| 474 hint = '%s has no element %r' % ( | |
| 475 object_type_repr(self._undefined_obj), | |
| 476 self._undefined_name | |
| 477 ) | |
| 478 else: | |
| 479 hint = '%r has no attribute %r' % ( | |
| 480 object_type_repr(self._undefined_obj), | |
| 481 self._undefined_name | |
| 482 ) | |
| 483 else: | |
| 484 hint = self._undefined_hint | |
| 485 raise self._undefined_exception(hint) | |
| 486 | |
| 487 @internalcode | |
| 488 def __getattr__(self, name): | |
| 489 if name[:2] == '__': | |
| 490 raise AttributeError(name) | |
| 491 return self._fail_with_undefined_error() | |
| 492 | |
| 493 __add__ = __radd__ = __mul__ = __rmul__ = __div__ = __rdiv__ = \ | |
| 494 __truediv__ = __rtruediv__ = __floordiv__ = __rfloordiv__ = \ | |
| 495 __mod__ = __rmod__ = __pos__ = __neg__ = __call__ = \ | |
| 496 __getitem__ = __lt__ = __le__ = __gt__ = __ge__ = __int__ = \ | |
| 497 __float__ = __complex__ = __pow__ = __rpow__ = \ | |
| 498 _fail_with_undefined_error | |
| 499 | |
| 500 def __eq__(self, other): | |
| 501 return type(self) is type(other) | |
| 502 | |
| 503 def __ne__(self, other): | |
| 504 return not self.__eq__(other) | |
| 505 | |
| 506 def __hash__(self): | |
| 507 return id(type(self)) | |
| 508 | |
| 509 def __str__(self): | |
| 510 return u'' | |
| 511 | |
| 512 def __len__(self): | |
| 513 return 0 | |
| 514 | |
| 515 def __iter__(self): | |
| 516 if 0: | |
| 517 yield None | |
| 518 | |
| 519 def __nonzero__(self): | |
| 520 return False | |
| 521 | |
| 522 def __repr__(self): | |
| 523 return 'Undefined' | |
| 524 | |
| 525 | |
| 526 @implements_to_string | |
| 527 class DebugUndefined(Undefined): | |
| 528 """An undefined that returns the debug info when printed. | |
| 529 | |
| 530 >>> foo = DebugUndefined(name='foo') | |
| 531 >>> str(foo) | |
| 532 '{{ foo }}' | |
| 533 >>> not foo | |
| 534 True | |
| 535 >>> foo + 42 | |
| 536 Traceback (most recent call last): | |
| 537 ... | |
| 538 UndefinedError: 'foo' is undefined | |
| 539 """ | |
| 540 __slots__ = () | |
| 541 | |
| 542 def __str__(self): | |
| 543 if self._undefined_hint is None: | |
| 544 if self._undefined_obj is missing: | |
| 545 return u'{{ %s }}' % self._undefined_name | |
| 546 return '{{ no such element: %s[%r] }}' % ( | |
| 547 object_type_repr(self._undefined_obj), | |
| 548 self._undefined_name | |
| 549 ) | |
| 550 return u'{{ undefined value printed: %s }}' % self._undefined_hint | |
| 551 | |
| 552 | |
| 553 @implements_to_string | |
| 554 class StrictUndefined(Undefined): | |
| 555 """An undefined that barks on print and iteration as well as boolean | |
| 556 tests and all kinds of comparisons. In other words: you can do nothing | |
| 557 with it except checking if it's defined using the `defined` test. | |
| 558 | |
| 559 >>> foo = StrictUndefined(name='foo') | |
| 560 >>> str(foo) | |
| 561 Traceback (most recent call last): | |
| 562 ... | |
| 563 UndefinedError: 'foo' is undefined | |
| 564 >>> not foo | |
| 565 Traceback (most recent call last): | |
| 566 ... | |
| 567 UndefinedError: 'foo' is undefined | |
| 568 >>> foo + 42 | |
| 569 Traceback (most recent call last): | |
| 570 ... | |
| 571 UndefinedError: 'foo' is undefined | |
| 572 """ | |
| 573 __slots__ = () | |
| 574 __iter__ = __str__ = __len__ = __nonzero__ = __eq__ = \ | |
| 575 __ne__ = __bool__ = __hash__ = \ | |
| 576 Undefined._fail_with_undefined_error | |
| 577 | |
| 578 | |
| 579 # remove remaining slots attributes, after the metaclass did the magic they | |
| 580 # are unneeded and irritating as they contain wrong data for the subclasses. | |
| 581 del Undefined.__slots__, DebugUndefined.__slots__, StrictUndefined.__slots__ | |
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