1"""Compiles nodes from the parser into Python code.""" 2import typing as t 3from contextlib import contextmanager 4from functools import update_wrapper 5from io import StringIO 6from itertools import chain 7from keyword import iskeyword as is_python_keyword 8 9from markupsafe import escape 10from markupsafe import Markup 11 12from . import nodes 13from .exceptions import TemplateAssertionError 14from .idtracking import Symbols 15from .idtracking import VAR_LOAD_ALIAS 16from .idtracking import VAR_LOAD_PARAMETER 17from .idtracking import VAR_LOAD_RESOLVE 18from .idtracking import VAR_LOAD_UNDEFINED 19from .nodes import EvalContext 20from .optimizer import Optimizer 21from .utils import _PassArg 22from .utils import concat 23from .visitor import NodeVisitor 24 25if t.TYPE_CHECKING: 26 import typing_extensions as te 27 from .environment import Environment 28 29F = t.TypeVar("F", bound=t.Callable[..., t.Any]) 30 31operators = { 32 "eq": "==", 33 "ne": "!=", 34 "gt": ">", 35 "gteq": ">=", 36 "lt": "<", 37 "lteq": "<=", 38 "in": "in", 39 "notin": "not in", 40} 41 42 43def optimizeconst(f: F) -> F: 44 def new_func( 45 self: "CodeGenerator", node: nodes.Expr, frame: "Frame", **kwargs: t.Any 46 ) -> t.Any: 47 # Only optimize if the frame is not volatile 48 if self.optimizer is not None and not frame.eval_ctx.volatile: 49 new_node = self.optimizer.visit(node, frame.eval_ctx) 50 51 if new_node != node: 52 return self.visit(new_node, frame) 53 54 return f(self, node, frame, **kwargs) 55 56 return update_wrapper(t.cast(F, new_func), f) 57 58 59def _make_binop(op: str) -> t.Callable[["CodeGenerator", nodes.BinExpr, "Frame"], None]: 60 @optimizeconst 61 def visitor(self: "CodeGenerator", node: nodes.BinExpr, frame: Frame) -> None: 62 if ( 63 self.environment.sandboxed 64 and op in self.environment.intercepted_binops # type: ignore 65 ): 66 self.write(f"environment.call_binop(context, {op!r}, ") 67 self.visit(node.left, frame) 68 self.write(", ") 69 self.visit(node.right, frame) 70 else: 71 self.write("(") 72 self.visit(node.left, frame) 73 self.write(f" {op} ") 74 self.visit(node.right, frame) 75 76 self.write(")") 77 78 return visitor 79 80 81def _make_unop( 82 op: str, 83) -> t.Callable[["CodeGenerator", nodes.UnaryExpr, "Frame"], None]: 84 @optimizeconst 85 def visitor(self: "CodeGenerator", node: nodes.UnaryExpr, frame: Frame) -> None: 86 if ( 87 self.environment.sandboxed 88 and op in self.environment.intercepted_unops # type: ignore 89 ): 90 self.write(f"environment.call_unop(context, {op!r}, ") 91 self.visit(node.node, frame) 92 else: 93 self.write("(" + op) 94 self.visit(node.node, frame) 95 96 self.write(")") 97 98 return visitor 99 100 101def generate( 102 node: nodes.Template, 103 environment: "Environment", 104 name: t.Optional[str], 105 filename: t.Optional[str], 106 stream: t.Optional[t.TextIO] = None, 107 defer_init: bool = False, 108 optimized: bool = True, 109) -> t.Optional[str]: 110 """Generate the python source for a node tree.""" 111 if not isinstance(node, nodes.Template): 112 raise TypeError("Can't compile non template nodes") 113 114 generator = environment.code_generator_class( 115 environment, name, filename, stream, defer_init, optimized 116 ) 117 generator.visit(node) 118 119 if stream is None: 120 return generator.stream.getvalue() # type: ignore 121 122 return None 123 124 125def has_safe_repr(value: t.Any) -> bool: 126 """Does the node have a safe representation?""" 127 if value is None or value is NotImplemented or value is Ellipsis: 128 return True 129 130 if type(value) in {bool, int, float, complex, range, str, Markup}: 131 return True 132 133 if type(value) in {tuple, list, set, frozenset}: 134 return all(has_safe_repr(v) for v in value) 135 136 if type(value) is dict: 137 return all(has_safe_repr(k) and has_safe_repr(v) for k, v in value.items()) 138 139 return False 140 141 142def find_undeclared( 143 nodes: t.Iterable[nodes.Node], names: t.Iterable[str] 144) -> t.Set[str]: 145 """Check if the names passed are accessed undeclared. The return value 146 is a set of all the undeclared names from the sequence of names found. 147 """ 148 visitor = UndeclaredNameVisitor(names) 149 try: 150 for node in nodes: 151 visitor.visit(node) 152 except VisitorExit: 153 pass 154 return visitor.undeclared 155 156 157class MacroRef: 158 def __init__(self, node: t.Union[nodes.Macro, nodes.CallBlock]) -> None: 159 self.node = node 160 self.accesses_caller = False 161 self.accesses_kwargs = False 162 self.accesses_varargs = False 163 164 165class Frame: 166 """Holds compile time information for us.""" 167 168 def __init__( 169 self, 170 eval_ctx: EvalContext, 171 parent: t.Optional["Frame"] = None, 172 level: t.Optional[int] = None, 173 ) -> None: 174 self.eval_ctx = eval_ctx 175 176 # the parent of this frame 177 self.parent = parent 178 179 if parent is None: 180 self.symbols = Symbols(level=level) 181 182 # in some dynamic inheritance situations the compiler needs to add 183 # write tests around output statements. 184 self.require_output_check = False 185 186 # inside some tags we are using a buffer rather than yield statements. 187 # this for example affects {% filter %} or {% macro %}. If a frame 188 # is buffered this variable points to the name of the list used as 189 # buffer. 190 self.buffer: t.Optional[str] = None 191 192 # the name of the block we're in, otherwise None. 193 self.block: t.Optional[str] = None 194 195 else: 196 self.symbols = Symbols(parent.symbols, level=level) 197 self.require_output_check = parent.require_output_check 198 self.buffer = parent.buffer 199 self.block = parent.block 200 201 # a toplevel frame is the root + soft frames such as if conditions. 202 self.toplevel = False 203 204 # the root frame is basically just the outermost frame, so no if 205 # conditions. This information is used to optimize inheritance 206 # situations. 207 self.rootlevel = False 208 209 # variables set inside of loops and blocks should not affect outer frames, 210 # but they still needs to be kept track of as part of the active context. 211 self.loop_frame = False 212 self.block_frame = False 213 214 # track whether the frame is being used in an if-statement or conditional 215 # expression as it determines which errors should be raised during runtime 216 # or compile time. 217 self.soft_frame = False 218 219 def copy(self) -> "Frame": 220 """Create a copy of the current one.""" 221 rv = object.__new__(self.__class__) 222 rv.__dict__.update(self.__dict__) 223 rv.symbols = self.symbols.copy() 224 return rv 225 226 def inner(self, isolated: bool = False) -> "Frame": 227 """Return an inner frame.""" 228 if isolated: 229 return Frame(self.eval_ctx, level=self.symbols.level + 1) 230 return Frame(self.eval_ctx, self) 231 232 def soft(self) -> "Frame": 233 """Return a soft frame. A soft frame may not be modified as 234 standalone thing as it shares the resources with the frame it 235 was created of, but it's not a rootlevel frame any longer. 236 237 This is only used to implement if-statements and conditional 238 expressions. 239 """ 240 rv = self.copy() 241 rv.rootlevel = False 242 rv.soft_frame = True 243 return rv 244 245 __copy__ = copy 246 247 248class VisitorExit(RuntimeError): 249 """Exception used by the `UndeclaredNameVisitor` to signal a stop.""" 250 251 252class DependencyFinderVisitor(NodeVisitor): 253 """A visitor that collects filter and test calls.""" 254 255 def __init__(self) -> None: 256 self.filters: t.Set[str] = set() 257 self.tests: t.Set[str] = set() 258 259 def visit_Filter(self, node: nodes.Filter) -> None: 260 self.generic_visit(node) 261 self.filters.add(node.name) 262 263 def visit_Test(self, node: nodes.Test) -> None: 264 self.generic_visit(node) 265 self.tests.add(node.name) 266 267 def visit_Block(self, node: nodes.Block) -> None: 268 """Stop visiting at blocks.""" 269 270 271class UndeclaredNameVisitor(NodeVisitor): 272 """A visitor that checks if a name is accessed without being 273 declared. This is different from the frame visitor as it will 274 not stop at closure frames. 275 """ 276 277 def __init__(self, names: t.Iterable[str]) -> None: 278 self.names = set(names) 279 self.undeclared: t.Set[str] = set() 280 281 def visit_Name(self, node: nodes.Name) -> None: 282 if node.ctx == "load" and node.name in self.names: 283 self.undeclared.add(node.name) 284 if self.undeclared == self.names: 285 raise VisitorExit() 286 else: 287 self.names.discard(node.name) 288 289 def visit_Block(self, node: nodes.Block) -> None: 290 """Stop visiting a blocks.""" 291 292 293class CompilerExit(Exception): 294 """Raised if the compiler encountered a situation where it just 295 doesn't make sense to further process the code. Any block that 296 raises such an exception is not further processed. 297 """ 298 299 300class CodeGenerator(NodeVisitor): 301 def __init__( 302 self, 303 environment: "Environment", 304 name: t.Optional[str], 305 filename: t.Optional[str], 306 stream: t.Optional[t.TextIO] = None, 307 defer_init: bool = False, 308 optimized: bool = True, 309 ) -> None: 310 if stream is None: 311 stream = StringIO() 312 self.environment = environment 313 self.name = name 314 self.filename = filename 315 self.stream = stream 316 self.created_block_context = False 317 self.defer_init = defer_init 318 self.optimizer: t.Optional[Optimizer] = None 319 320 if optimized: 321 self.optimizer = Optimizer(environment) 322 323 # aliases for imports 324 self.import_aliases: t.Dict[str, str] = {} 325 326 # a registry for all blocks. Because blocks are moved out 327 # into the global python scope they are registered here 328 self.blocks: t.Dict[str, nodes.Block] = {} 329 330 # the number of extends statements so far 331 self.extends_so_far = 0 332 333 # some templates have a rootlevel extends. In this case we 334 # can safely assume that we're a child template and do some 335 # more optimizations. 336 self.has_known_extends = False 337 338 # the current line number 339 self.code_lineno = 1 340 341 # registry of all filters and tests (global, not block local) 342 self.tests: t.Dict[str, str] = {} 343 self.filters: t.Dict[str, str] = {} 344 345 # the debug information 346 self.debug_info: t.List[t.Tuple[int, int]] = [] 347 self._write_debug_info: t.Optional[int] = None 348 349 # the number of new lines before the next write() 350 self._new_lines = 0 351 352 # the line number of the last written statement 353 self._last_line = 0 354 355 # true if nothing was written so far. 356 self._first_write = True 357 358 # used by the `temporary_identifier` method to get new 359 # unique, temporary identifier 360 self._last_identifier = 0 361 362 # the current indentation 363 self._indentation = 0 364 365 # Tracks toplevel assignments 366 self._assign_stack: t.List[t.Set[str]] = [] 367 368 # Tracks parameter definition blocks 369 self._param_def_block: t.List[t.Set[str]] = [] 370 371 # Tracks the current context. 372 self._context_reference_stack = ["context"] 373 374 @property 375 def optimized(self) -> bool: 376 return self.optimizer is not None 377 378 # -- Various compilation helpers 379 380 def fail(self, msg: str, lineno: int) -> "te.NoReturn": 381 """Fail with a :exc:`TemplateAssertionError`.""" 382 raise TemplateAssertionError(msg, lineno, self.name, self.filename) 383 384 def temporary_identifier(self) -> str: 385 """Get a new unique identifier.""" 386 self._last_identifier += 1 387 return f"t_{self._last_identifier}" 388 389 def buffer(self, frame: Frame) -> None: 390 """Enable buffering for the frame from that point onwards.""" 391 frame.buffer = self.temporary_identifier() 392 self.writeline(f"{frame.buffer} = []") 393 394 def return_buffer_contents( 395 self, frame: Frame, force_unescaped: bool = False 396 ) -> None: 397 """Return the buffer contents of the frame.""" 398 if not force_unescaped: 399 if frame.eval_ctx.volatile: 400 self.writeline("if context.eval_ctx.autoescape:") 401 self.indent() 402 self.writeline(f"return Markup(concat({frame.buffer}))") 403 self.outdent() 404 self.writeline("else:") 405 self.indent() 406 self.writeline(f"return concat({frame.buffer})") 407 self.outdent() 408 return 409 elif frame.eval_ctx.autoescape: 410 self.writeline(f"return Markup(concat({frame.buffer}))") 411 return 412 self.writeline(f"return concat({frame.buffer})") 413 414 def indent(self) -> None: 415 """Indent by one.""" 416 self._indentation += 1 417 418 def outdent(self, step: int = 1) -> None: 419 """Outdent by step.""" 420 self._indentation -= step 421 422 def start_write(self, frame: Frame, node: t.Optional[nodes.Node] = None) -> None: 423 """Yield or write into the frame buffer.""" 424 if frame.buffer is None: 425 self.writeline("yield ", node) 426 else: 427 self.writeline(f"{frame.buffer}.append(", node) 428 429 def end_write(self, frame: Frame) -> None: 430 """End the writing process started by `start_write`.""" 431 if frame.buffer is not None: 432 self.write(")") 433 434 def simple_write( 435 self, s: str, frame: Frame, node: t.Optional[nodes.Node] = None 436 ) -> None: 437 """Simple shortcut for start_write + write + end_write.""" 438 self.start_write(frame, node) 439 self.write(s) 440 self.end_write(frame) 441 442 def blockvisit(self, nodes: t.Iterable[nodes.Node], frame: Frame) -> None: 443 """Visit a list of nodes as block in a frame. If the current frame 444 is no buffer a dummy ``if 0: yield None`` is written automatically. 445 """ 446 try: 447 self.writeline("pass") 448 for node in nodes: 449 self.visit(node, frame) 450 except CompilerExit: 451 pass 452 453 def write(self, x: str) -> None: 454 """Write a string into the output stream.""" 455 if self._new_lines: 456 if not self._first_write: 457 self.stream.write("\n" * self._new_lines) 458 self.code_lineno += self._new_lines 459 if self._write_debug_info is not None: 460 self.debug_info.append((self._write_debug_info, self.code_lineno)) 461 self._write_debug_info = None 462 self._first_write = False 463 self.stream.write(" " * self._indentation) 464 self._new_lines = 0 465 self.stream.write(x) 466 467 def writeline( 468 self, x: str, node: t.Optional[nodes.Node] = None, extra: int = 0 469 ) -> None: 470 """Combination of newline and write.""" 471 self.newline(node, extra) 472 self.write(x) 473 474 def newline(self, node: t.Optional[nodes.Node] = None, extra: int = 0) -> None: 475 """Add one or more newlines before the next write.""" 476 self._new_lines = max(self._new_lines, 1 + extra) 477 if node is not None and node.lineno != self._last_line: 478 self._write_debug_info = node.lineno 479 self._last_line = node.lineno 480 481 def signature( 482 self, 483 node: t.Union[nodes.Call, nodes.Filter, nodes.Test], 484 frame: Frame, 485 extra_kwargs: t.Optional[t.Mapping[str, t.Any]] = None, 486 ) -> None: 487 """Writes a function call to the stream for the current node. 488 A leading comma is added automatically. The extra keyword 489 arguments may not include python keywords otherwise a syntax 490 error could occur. The extra keyword arguments should be given 491 as python dict. 492 """ 493 # if any of the given keyword arguments is a python keyword 494 # we have to make sure that no invalid call is created. 495 kwarg_workaround = any( 496 is_python_keyword(t.cast(str, k)) 497 for k in chain((x.key for x in node.kwargs), extra_kwargs or ()) 498 ) 499 500 for arg in node.args: 501 self.write(", ") 502 self.visit(arg, frame) 503 504 if not kwarg_workaround: 505 for kwarg in node.kwargs: 506 self.write(", ") 507 self.visit(kwarg, frame) 508 if extra_kwargs is not None: 509 for key, value in extra_kwargs.items(): 510 self.write(f", {key}={value}") 511 if node.dyn_args: 512 self.write(", *") 513 self.visit(node.dyn_args, frame) 514 515 if kwarg_workaround: 516 if node.dyn_kwargs is not None: 517 self.write(", **dict({") 518 else: 519 self.write(", **{") 520 for kwarg in node.kwargs: 521 self.write(f"{kwarg.key!r}: ") 522 self.visit(kwarg.value, frame) 523 self.write(", ") 524 if extra_kwargs is not None: 525 for key, value in extra_kwargs.items(): 526 self.write(f"{key!r}: {value}, ") 527 if node.dyn_kwargs is not None: 528 self.write("}, **") 529 self.visit(node.dyn_kwargs, frame) 530 self.write(")") 531 else: 532 self.write("}") 533 534 elif node.dyn_kwargs is not None: 535 self.write(", **") 536 self.visit(node.dyn_kwargs, frame) 537 538 def pull_dependencies(self, nodes: t.Iterable[nodes.Node]) -> None: 539 """Find all filter and test names used in the template and 540 assign them to variables in the compiled namespace. Checking 541 that the names are registered with the environment is done when 542 compiling the Filter and Test nodes. If the node is in an If or 543 CondExpr node, the check is done at runtime instead. 544 545 .. versionchanged:: 3.0 546 Filters and tests in If and CondExpr nodes are checked at 547 runtime instead of compile time. 548 """ 549 visitor = DependencyFinderVisitor() 550 551 for node in nodes: 552 visitor.visit(node) 553 554 for id_map, names, dependency in (self.filters, visitor.filters, "filters"), ( 555 self.tests, 556 visitor.tests, 557 "tests", 558 ): 559 for name in sorted(names): 560 if name not in id_map: 561 id_map[name] = self.temporary_identifier() 562 563 # add check during runtime that dependencies used inside of executed 564 # blocks are defined, as this step may be skipped during compile time 565 self.writeline("try:") 566 self.indent() 567 self.writeline(f"{id_map[name]} = environment.{dependency}[{name!r}]") 568 self.outdent() 569 self.writeline("except KeyError:") 570 self.indent() 571 self.writeline("@internalcode") 572 self.writeline(f"def {id_map[name]}(*unused):") 573 self.indent() 574 self.writeline( 575 f'raise TemplateRuntimeError("No {dependency[:-1]}' 576 f' named {name!r} found.")' 577 ) 578 self.outdent() 579 self.outdent() 580 581 def enter_frame(self, frame: Frame) -> None: 582 undefs = [] 583 for target, (action, param) in frame.symbols.loads.items(): 584 if action == VAR_LOAD_PARAMETER: 585 pass 586 elif action == VAR_LOAD_RESOLVE: 587 self.writeline(f"{target} = {self.get_resolve_func()}({param!r})") 588 elif action == VAR_LOAD_ALIAS: 589 self.writeline(f"{target} = {param}") 590 elif action == VAR_LOAD_UNDEFINED: 591 undefs.append(target) 592 else: 593 raise NotImplementedError("unknown load instruction") 594 if undefs: 595 self.writeline(f"{' = '.join(undefs)} = missing") 596 597 def leave_frame(self, frame: Frame, with_python_scope: bool = False) -> None: 598 if not with_python_scope: 599 undefs = [] 600 for target in frame.symbols.loads: 601 undefs.append(target) 602 if undefs: 603 self.writeline(f"{' = '.join(undefs)} = missing") 604 605 def choose_async(self, async_value: str = "async ", sync_value: str = "") -> str: 606 return async_value if self.environment.is_async else sync_value 607 608 def func(self, name: str) -> str: 609 return f"{self.choose_async()}def {name}" 610 611 def macro_body( 612 self, node: t.Union[nodes.Macro, nodes.CallBlock], frame: Frame 613 ) -> t.Tuple[Frame, MacroRef]: 614 """Dump the function def of a macro or call block.""" 615 frame = frame.inner() 616 frame.symbols.analyze_node(node) 617 macro_ref = MacroRef(node) 618 619 explicit_caller = None 620 skip_special_params = set() 621 args = [] 622 623 for idx, arg in enumerate(node.args): 624 if arg.name == "caller": 625 explicit_caller = idx 626 if arg.name in ("kwargs", "varargs"): 627 skip_special_params.add(arg.name) 628 args.append(frame.symbols.ref(arg.name)) 629 630 undeclared = find_undeclared(node.body, ("caller", "kwargs", "varargs")) 631 632 if "caller" in undeclared: 633 # In older Jinja versions there was a bug that allowed caller 634 # to retain the special behavior even if it was mentioned in 635 # the argument list. However thankfully this was only really 636 # working if it was the last argument. So we are explicitly 637 # checking this now and error out if it is anywhere else in 638 # the argument list. 639 if explicit_caller is not None: 640 try: 641 node.defaults[explicit_caller - len(node.args)] 642 except IndexError: 643 self.fail( 644 "When defining macros or call blocks the " 645 'special "caller" argument must be omitted ' 646 "or be given a default.", 647 node.lineno, 648 ) 649 else: 650 args.append(frame.symbols.declare_parameter("caller")) 651 macro_ref.accesses_caller = True 652 if "kwargs" in undeclared and "kwargs" not in skip_special_params: 653 args.append(frame.symbols.declare_parameter("kwargs")) 654 macro_ref.accesses_kwargs = True 655 if "varargs" in undeclared and "varargs" not in skip_special_params: 656 args.append(frame.symbols.declare_parameter("varargs")) 657 macro_ref.accesses_varargs = True 658 659 # macros are delayed, they never require output checks 660 frame.require_output_check = False 661 frame.symbols.analyze_node(node) 662 self.writeline(f"{self.func('macro')}({', '.join(args)}):", node) 663 self.indent() 664 665 self.buffer(frame) 666 self.enter_frame(frame) 667 668 self.push_parameter_definitions(frame) 669 for idx, arg in enumerate(node.args): 670 ref = frame.symbols.ref(arg.name) 671 self.writeline(f"if {ref} is missing:") 672 self.indent() 673 try: 674 default = node.defaults[idx - len(node.args)] 675 except IndexError: 676 self.writeline( 677 f'{ref} = undefined("parameter {arg.name!r} was not provided",' 678 f" name={arg.name!r})" 679 ) 680 else: 681 self.writeline(f"{ref} = ") 682 self.visit(default, frame) 683 self.mark_parameter_stored(ref) 684 self.outdent() 685 self.pop_parameter_definitions() 686 687 self.blockvisit(node.body, frame) 688 self.return_buffer_contents(frame, force_unescaped=True) 689 self.leave_frame(frame, with_python_scope=True) 690 self.outdent() 691 692 return frame, macro_ref 693 694 def macro_def(self, macro_ref: MacroRef, frame: Frame) -> None: 695 """Dump the macro definition for the def created by macro_body.""" 696 arg_tuple = ", ".join(repr(x.name) for x in macro_ref.node.args) 697 name = getattr(macro_ref.node, "name", None) 698 if len(macro_ref.node.args) == 1: 699 arg_tuple += "," 700 self.write( 701 f"Macro(environment, macro, {name!r}, ({arg_tuple})," 702 f" {macro_ref.accesses_kwargs!r}, {macro_ref.accesses_varargs!r}," 703 f" {macro_ref.accesses_caller!r}, context.eval_ctx.autoescape)" 704 ) 705 706 def position(self, node: nodes.Node) -> str: 707 """Return a human readable position for the node.""" 708 rv = f"line {node.lineno}" 709 if self.name is not None: 710 rv = f"{rv} in {self.name!r}" 711 return rv 712 713 def dump_local_context(self, frame: Frame) -> str: 714 items_kv = ", ".join( 715 f"{name!r}: {target}" 716 for name, target in frame.symbols.dump_stores().items() 717 ) 718 return f"{{{items_kv}}}" 719 720 def write_commons(self) -> None: 721 """Writes a common preamble that is used by root and block functions. 722 Primarily this sets up common local helpers and enforces a generator 723 through a dead branch. 724 """ 725 self.writeline("resolve = context.resolve_or_missing") 726 self.writeline("undefined = environment.undefined") 727 self.writeline("concat = environment.concat") 728 # always use the standard Undefined class for the implicit else of 729 # conditional expressions 730 self.writeline("cond_expr_undefined = Undefined") 731 self.writeline("if 0: yield None") 732 733 def push_parameter_definitions(self, frame: Frame) -> None: 734 """Pushes all parameter targets from the given frame into a local 735 stack that permits tracking of yet to be assigned parameters. In 736 particular this enables the optimization from `visit_Name` to skip 737 undefined expressions for parameters in macros as macros can reference 738 otherwise unbound parameters. 739 """ 740 self._param_def_block.append(frame.symbols.dump_param_targets()) 741 742 def pop_parameter_definitions(self) -> None: 743 """Pops the current parameter definitions set.""" 744 self._param_def_block.pop() 745 746 def mark_parameter_stored(self, target: str) -> None: 747 """Marks a parameter in the current parameter definitions as stored. 748 This will skip the enforced undefined checks. 749 """ 750 if self._param_def_block: 751 self._param_def_block[-1].discard(target) 752 753 def push_context_reference(self, target: str) -> None: 754 self._context_reference_stack.append(target) 755 756 def pop_context_reference(self) -> None: 757 self._context_reference_stack.pop() 758 759 def get_context_ref(self) -> str: 760 return self._context_reference_stack[-1] 761 762 def get_resolve_func(self) -> str: 763 target = self._context_reference_stack[-1] 764 if target == "context": 765 return "resolve" 766 return f"{target}.resolve" 767 768 def derive_context(self, frame: Frame) -> str: 769 return f"{self.get_context_ref()}.derived({self.dump_local_context(frame)})" 770 771 def parameter_is_undeclared(self, target: str) -> bool: 772 """Checks if a given target is an undeclared parameter.""" 773 if not self._param_def_block: 774 return False 775 return target in self._param_def_block[-1] 776 777 def push_assign_tracking(self) -> None: 778 """Pushes a new layer for assignment tracking.""" 779 self._assign_stack.append(set()) 780 781 def pop_assign_tracking(self, frame: Frame) -> None: 782 """Pops the topmost level for assignment tracking and updates the 783 context variables if necessary. 784 """ 785 vars = self._assign_stack.pop() 786 if ( 787 not frame.block_frame 788 and not frame.loop_frame 789 and not frame.toplevel 790 or not vars 791 ): 792 return 793 public_names = [x for x in vars if x[:1] != "_"] 794 if len(vars) == 1: 795 name = next(iter(vars)) 796 ref = frame.symbols.ref(name) 797 if frame.loop_frame: 798 self.writeline(f"_loop_vars[{name!r}] = {ref}") 799 return 800 if frame.block_frame: 801 self.writeline(f"_block_vars[{name!r}] = {ref}") 802 return 803 self.writeline(f"context.vars[{name!r}] = {ref}") 804 else: 805 if frame.loop_frame: 806 self.writeline("_loop_vars.update({") 807 elif frame.block_frame: 808 self.writeline("_block_vars.update({") 809 else: 810 self.writeline("context.vars.update({") 811 for idx, name in enumerate(vars): 812 if idx: 813 self.write(", ") 814 ref = frame.symbols.ref(name) 815 self.write(f"{name!r}: {ref}") 816 self.write("})") 817 if not frame.block_frame and not frame.loop_frame and public_names: 818 if len(public_names) == 1: 819 self.writeline(f"context.exported_vars.add({public_names[0]!r})") 820 else: 821 names_str = ", ".join(map(repr, public_names)) 822 self.writeline(f"context.exported_vars.update(({names_str}))") 823 824 # -- Statement Visitors 825 826 def visit_Template( 827 self, node: nodes.Template, frame: t.Optional[Frame] = None 828 ) -> None: 829 assert frame is None, "no root frame allowed" 830 eval_ctx = EvalContext(self.environment, self.name) 831 832 from .runtime import exported, async_exported 833 834 if self.environment.is_async: 835 exported_names = sorted(exported + async_exported) 836 else: 837 exported_names = sorted(exported) 838 839 self.writeline("from jinja2.runtime import " + ", ".join(exported_names)) 840 841 # if we want a deferred initialization we cannot move the 842 # environment into a local name 843 envenv = "" if self.defer_init else ", environment=environment" 844 845 # do we have an extends tag at all? If not, we can save some 846 # overhead by just not processing any inheritance code. 847 have_extends = node.find(nodes.Extends) is not None 848 849 # find all blocks 850 for block in node.find_all(nodes.Block): 851 if block.name in self.blocks: 852 self.fail(f"block {block.name!r} defined twice", block.lineno) 853 self.blocks[block.name] = block 854 855 # find all imports and import them 856 for import_ in node.find_all(nodes.ImportedName): 857 if import_.importname not in self.import_aliases: 858 imp = import_.importname 859 self.import_aliases[imp] = alias = self.temporary_identifier() 860 if "." in imp: 861 module, obj = imp.rsplit(".", 1) 862 self.writeline(f"from {module} import {obj} as {alias}") 863 else: 864 self.writeline(f"import {imp} as {alias}") 865 866 # add the load name 867 self.writeline(f"name = {self.name!r}") 868 869 # generate the root render function. 870 self.writeline( 871 f"{self.func('root')}(context, missing=missing{envenv}):", extra=1 872 ) 873 self.indent() 874 self.write_commons() 875 876 # process the root 877 frame = Frame(eval_ctx) 878 if "self" in find_undeclared(node.body, ("self",)): 879 ref = frame.symbols.declare_parameter("self") 880 self.writeline(f"{ref} = TemplateReference(context)") 881 frame.symbols.analyze_node(node) 882 frame.toplevel = frame.rootlevel = True 883 frame.require_output_check = have_extends and not self.has_known_extends 884 if have_extends: 885 self.writeline("parent_template = None") 886 self.enter_frame(frame) 887 self.pull_dependencies(node.body) 888 self.blockvisit(node.body, frame) 889 self.leave_frame(frame, with_python_scope=True) 890 self.outdent() 891 892 # make sure that the parent root is called. 893 if have_extends: 894 if not self.has_known_extends: 895 self.indent() 896 self.writeline("if parent_template is not None:") 897 self.indent() 898 if not self.environment.is_async: 899 self.writeline("yield from parent_template.root_render_func(context)") 900 else: 901 self.writeline( 902 "async for event in parent_template.root_render_func(context):" 903 ) 904 self.indent() 905 self.writeline("yield event") 906 self.outdent() 907 self.outdent(1 + (not self.has_known_extends)) 908 909 # at this point we now have the blocks collected and can visit them too. 910 for name, block in self.blocks.items(): 911 self.writeline( 912 f"{self.func('block_' + name)}(context, missing=missing{envenv}):", 913 block, 914 1, 915 ) 916 self.indent() 917 self.write_commons() 918 # It's important that we do not make this frame a child of the 919 # toplevel template. This would cause a variety of 920 # interesting issues with identifier tracking. 921 block_frame = Frame(eval_ctx) 922 block_frame.block_frame = True 923 undeclared = find_undeclared(block.body, ("self", "super")) 924 if "self" in undeclared: 925 ref = block_frame.symbols.declare_parameter("self") 926 self.writeline(f"{ref} = TemplateReference(context)") 927 if "super" in undeclared: 928 ref = block_frame.symbols.declare_parameter("super") 929 self.writeline(f"{ref} = context.super({name!r}, block_{name})") 930 block_frame.symbols.analyze_node(block) 931 block_frame.block = name 932 self.writeline("_block_vars = {}") 933 self.enter_frame(block_frame) 934 self.pull_dependencies(block.body) 935 self.blockvisit(block.body, block_frame) 936 self.leave_frame(block_frame, with_python_scope=True) 937 self.outdent() 938 939 blocks_kv_str = ", ".join(f"{x!r}: block_{x}" for x in self.blocks) 940 self.writeline(f"blocks = {{{blocks_kv_str}}}", extra=1) 941 debug_kv_str = "&".join(f"{k}={v}" for k, v in self.debug_info) 942 self.writeline(f"debug_info = {debug_kv_str!r}") 943 944 def visit_Block(self, node: nodes.Block, frame: Frame) -> None: 945 """Call a block and register it for the template.""" 946 level = 0 947 if frame.toplevel: 948 # if we know that we are a child template, there is no need to 949 # check if we are one 950 if self.has_known_extends: 951 return 952 if self.extends_so_far > 0: 953 self.writeline("if parent_template is None:") 954 self.indent() 955 level += 1 956 957 if node.scoped: 958 context = self.derive_context(frame) 959 else: 960 context = self.get_context_ref() 961 962 if node.required: 963 self.writeline(f"if len(context.blocks[{node.name!r}]) <= 1:", node) 964 self.indent() 965 self.writeline( 966 f'raise TemplateRuntimeError("Required block {node.name!r} not found")', 967 node, 968 ) 969 self.outdent() 970 971 if not self.environment.is_async and frame.buffer is None: 972 self.writeline( 973 f"yield from context.blocks[{node.name!r}][0]({context})", node 974 ) 975 else: 976 self.writeline( 977 f"{self.choose_async()}for event in" 978 f" context.blocks[{node.name!r}][0]({context}):", 979 node, 980 ) 981 self.indent() 982 self.simple_write("event", frame) 983 self.outdent() 984 985 self.outdent(level) 986 987 def visit_Extends(self, node: nodes.Extends, frame: Frame) -> None: 988 """Calls the extender.""" 989 if not frame.toplevel: 990 self.fail("cannot use extend from a non top-level scope", node.lineno) 991 992 # if the number of extends statements in general is zero so 993 # far, we don't have to add a check if something extended 994 # the template before this one. 995 if self.extends_so_far > 0: 996 # if we have a known extends we just add a template runtime 997 # error into the generated code. We could catch that at compile 998 # time too, but i welcome it not to confuse users by throwing the 999 # same error at different times just "because we can". 1000 if not self.has_known_extends: 1001 self.writeline("if parent_template is not None:") 1002 self.indent() 1003 self.writeline('raise TemplateRuntimeError("extended multiple times")') 1004 1005 # if we have a known extends already we don't need that code here 1006 # as we know that the template execution will end here. 1007 if self.has_known_extends: 1008 raise CompilerExit() 1009 else: 1010 self.outdent() 1011 1012 self.writeline("parent_template = environment.get_template(", node) 1013 self.visit(node.template, frame) 1014 self.write(f", {self.name!r})") 1015 self.writeline("for name, parent_block in parent_template.blocks.items():") 1016 self.indent() 1017 self.writeline("context.blocks.setdefault(name, []).append(parent_block)") 1018 self.outdent() 1019 1020 # if this extends statement was in the root level we can take 1021 # advantage of that information and simplify the generated code 1022 # in the top level from this point onwards 1023 if frame.rootlevel: 1024 self.has_known_extends = True 1025 1026 # and now we have one more 1027 self.extends_so_far += 1 1028 1029 def visit_Include(self, node: nodes.Include, frame: Frame) -> None: 1030 """Handles includes.""" 1031 if node.ignore_missing: 1032 self.writeline("try:") 1033 self.indent() 1034 1035 func_name = "get_or_select_template" 1036 if isinstance(node.template, nodes.Const): 1037 if isinstance(node.template.value, str): 1038 func_name = "get_template" 1039 elif isinstance(node.template.value, (tuple, list)): 1040 func_name = "select_template" 1041 elif isinstance(node.template, (nodes.Tuple, nodes.List)): 1042 func_name = "select_template" 1043 1044 self.writeline(f"template = environment.{func_name}(", node) 1045 self.visit(node.template, frame) 1046 self.write(f", {self.name!r})") 1047 if node.ignore_missing: 1048 self.outdent() 1049 self.writeline("except TemplateNotFound:") 1050 self.indent() 1051 self.writeline("pass") 1052 self.outdent() 1053 self.writeline("else:") 1054 self.indent() 1055 1056 skip_event_yield = False 1057 if node.with_context: 1058 self.writeline( 1059 f"{self.choose_async()}for event in template.root_render_func(" 1060 "template.new_context(context.get_all(), True," 1061 f" {self.dump_local_context(frame)})):" 1062 ) 1063 elif self.environment.is_async: 1064 self.writeline( 1065 "for event in (await template._get_default_module_async())" 1066 "._body_stream:" 1067 ) 1068 else: 1069 self.writeline("yield from template._get_default_module()._body_stream") 1070 skip_event_yield = True 1071 1072 if not skip_event_yield: 1073 self.indent() 1074 self.simple_write("event", frame) 1075 self.outdent() 1076 1077 if node.ignore_missing: 1078 self.outdent() 1079 1080 def _import_common( 1081 self, node: t.Union[nodes.Import, nodes.FromImport], frame: Frame 1082 ) -> None: 1083 self.write(f"{self.choose_async('await ')}environment.get_template(") 1084 self.visit(node.template, frame) 1085 self.write(f", {self.name!r}).") 1086 1087 if node.with_context: 1088 f_name = f"make_module{self.choose_async('_async')}" 1089 self.write( 1090 f"{f_name}(context.get_all(), True, {self.dump_local_context(frame)})" 1091 ) 1092 else: 1093 self.write(f"_get_default_module{self.choose_async('_async')}(context)") 1094 1095 def visit_Import(self, node: nodes.Import, frame: Frame) -> None: 1096 """Visit regular imports.""" 1097 self.writeline(f"{frame.symbols.ref(node.target)} = ", node) 1098 if frame.toplevel: 1099 self.write(f"context.vars[{node.target!r}] = ") 1100 1101 self._import_common(node, frame) 1102 1103 if frame.toplevel and not node.target.startswith("_"): 1104 self.writeline(f"context.exported_vars.discard({node.target!r})") 1105 1106 def visit_FromImport(self, node: nodes.FromImport, frame: Frame) -> None: 1107 """Visit named imports.""" 1108 self.newline(node) 1109 self.write("included_template = ") 1110 self._import_common(node, frame) 1111 var_names = [] 1112 discarded_names = [] 1113 for name in node.names: 1114 if isinstance(name, tuple): 1115 name, alias = name 1116 else: 1117 alias = name 1118 self.writeline( 1119 f"{frame.symbols.ref(alias)} =" 1120 f" getattr(included_template, {name!r}, missing)" 1121 ) 1122 self.writeline(f"if {frame.symbols.ref(alias)} is missing:") 1123 self.indent() 1124 message = ( 1125 "the template {included_template.__name__!r}" 1126 f" (imported on {self.position(node)})" 1127 f" does not export the requested name {name!r}" 1128 ) 1129 self.writeline( 1130 f"{frame.symbols.ref(alias)} = undefined(f{message!r}, name={name!r})" 1131 ) 1132 self.outdent() 1133 if frame.toplevel: 1134 var_names.append(alias) 1135 if not alias.startswith("_"): 1136 discarded_names.append(alias) 1137 1138 if var_names: 1139 if len(var_names) == 1: 1140 name = var_names[0] 1141 self.writeline(f"context.vars[{name!r}] = {frame.symbols.ref(name)}") 1142 else: 1143 names_kv = ", ".join( 1144 f"{name!r}: {frame.symbols.ref(name)}" for name in var_names 1145 ) 1146 self.writeline(f"context.vars.update({{{names_kv}}})") 1147 if discarded_names: 1148 if len(discarded_names) == 1: 1149 self.writeline(f"context.exported_vars.discard({discarded_names[0]!r})") 1150 else: 1151 names_str = ", ".join(map(repr, discarded_names)) 1152 self.writeline( 1153 f"context.exported_vars.difference_update(({names_str}))" 1154 ) 1155 1156 def visit_For(self, node: nodes.For, frame: Frame) -> None: 1157 loop_frame = frame.inner() 1158 loop_frame.loop_frame = True 1159 test_frame = frame.inner() 1160 else_frame = frame.inner() 1161 1162 # try to figure out if we have an extended loop. An extended loop 1163 # is necessary if the loop is in recursive mode if the special loop 1164 # variable is accessed in the body if the body is a scoped block. 1165 extended_loop = ( 1166 node.recursive 1167 or "loop" 1168 in find_undeclared(node.iter_child_nodes(only=("body",)), ("loop",)) 1169 or any(block.scoped for block in node.find_all(nodes.Block)) 1170 ) 1171 1172 loop_ref = None 1173 if extended_loop: 1174 loop_ref = loop_frame.symbols.declare_parameter("loop") 1175 1176 loop_frame.symbols.analyze_node(node, for_branch="body") 1177 if node.else_: 1178 else_frame.symbols.analyze_node(node, for_branch="else") 1179 1180 if node.test: 1181 loop_filter_func = self.temporary_identifier() 1182 test_frame.symbols.analyze_node(node, for_branch="test") 1183 self.writeline(f"{self.func(loop_filter_func)}(fiter):", node.test) 1184 self.indent() 1185 self.enter_frame(test_frame) 1186 self.writeline(self.choose_async("async for ", "for ")) 1187 self.visit(node.target, loop_frame) 1188 self.write(" in ") 1189 self.write(self.choose_async("auto_aiter(fiter)", "fiter")) 1190 self.write(":") 1191 self.indent() 1192 self.writeline("if ", node.test) 1193 self.visit(node.test, test_frame) 1194 self.write(":") 1195 self.indent() 1196 self.writeline("yield ") 1197 self.visit(node.target, loop_frame) 1198 self.outdent(3) 1199 self.leave_frame(test_frame, with_python_scope=True) 1200 1201 # if we don't have an recursive loop we have to find the shadowed 1202 # variables at that point. Because loops can be nested but the loop 1203 # variable is a special one we have to enforce aliasing for it. 1204 if node.recursive: 1205 self.writeline( 1206 f"{self.func('loop')}(reciter, loop_render_func, depth=0):", node 1207 ) 1208 self.indent() 1209 self.buffer(loop_frame) 1210 1211 # Use the same buffer for the else frame 1212 else_frame.buffer = loop_frame.buffer 1213 1214 # make sure the loop variable is a special one and raise a template 1215 # assertion error if a loop tries to write to loop 1216 if extended_loop: 1217 self.writeline(f"{loop_ref} = missing") 1218 1219 for name in node.find_all(nodes.Name): 1220 if name.ctx == "store" and name.name == "loop": 1221 self.fail( 1222 "Can't assign to special loop variable in for-loop target", 1223 name.lineno, 1224 ) 1225 1226 if node.else_: 1227 iteration_indicator = self.temporary_identifier() 1228 self.writeline(f"{iteration_indicator} = 1") 1229 1230 self.writeline(self.choose_async("async for ", "for "), node) 1231 self.visit(node.target, loop_frame) 1232 if extended_loop: 1233 self.write(f", {loop_ref} in {self.choose_async('Async')}LoopContext(") 1234 else: 1235 self.write(" in ") 1236 1237 if node.test: 1238 self.write(f"{loop_filter_func}(") 1239 if node.recursive: 1240 self.write("reciter") 1241 else: 1242 if self.environment.is_async and not extended_loop: 1243 self.write("auto_aiter(") 1244 self.visit(node.iter, frame) 1245 if self.environment.is_async and not extended_loop: 1246 self.write(")") 1247 if node.test: 1248 self.write(")") 1249 1250 if node.recursive: 1251 self.write(", undefined, loop_render_func, depth):") 1252 else: 1253 self.write(", undefined):" if extended_loop else ":") 1254 1255 self.indent() 1256 self.enter_frame(loop_frame) 1257 1258 self.writeline("_loop_vars = {}") 1259 self.blockvisit(node.body, loop_frame) 1260 if node.else_: 1261 self.writeline(f"{iteration_indicator} = 0") 1262 self.outdent() 1263 self.leave_frame( 1264 loop_frame, with_python_scope=node.recursive and not node.else_ 1265 ) 1266 1267 if node.else_: 1268 self.writeline(f"if {iteration_indicator}:") 1269 self.indent() 1270 self.enter_frame(else_frame) 1271 self.blockvisit(node.else_, else_frame) 1272 self.leave_frame(else_frame) 1273 self.outdent() 1274 1275 # if the node was recursive we have to return the buffer contents 1276 # and start the iteration code 1277 if node.recursive: 1278 self.return_buffer_contents(loop_frame) 1279 self.outdent() 1280 self.start_write(frame, node) 1281 self.write(f"{self.choose_async('await ')}loop(") 1282 if self.environment.is_async: 1283 self.write("auto_aiter(") 1284 self.visit(node.iter, frame) 1285 if self.environment.is_async: 1286 self.write(")") 1287 self.write(", loop)") 1288 self.end_write(frame) 1289 1290 # at the end of the iteration, clear any assignments made in the 1291 # loop from the top level 1292 if self._assign_stack: 1293 self._assign_stack[-1].difference_update(loop_frame.symbols.stores) 1294 1295 def visit_If(self, node: nodes.If, frame: Frame) -> None: 1296 if_frame = frame.soft() 1297 self.writeline("if ", node) 1298 self.visit(node.test, if_frame) 1299 self.write(":") 1300 self.indent() 1301 self.blockvisit(node.body, if_frame) 1302 self.outdent() 1303 for elif_ in node.elif_: 1304 self.writeline("elif ", elif_) 1305 self.visit(elif_.test, if_frame) 1306 self.write(":") 1307 self.indent() 1308 self.blockvisit(elif_.body, if_frame) 1309 self.outdent() 1310 if node.else_: 1311 self.writeline("else:") 1312 self.indent() 1313 self.blockvisit(node.else_, if_frame) 1314 self.outdent() 1315 1316 def visit_Macro(self, node: nodes.Macro, frame: Frame) -> None: 1317 macro_frame, macro_ref = self.macro_body(node, frame) 1318 self.newline() 1319 if frame.toplevel: 1320 if not node.name.startswith("_"): 1321 self.write(f"context.exported_vars.add({node.name!r})") 1322 self.writeline(f"context.vars[{node.name!r}] = ") 1323 self.write(f"{frame.symbols.ref(node.name)} = ") 1324 self.macro_def(macro_ref, macro_frame) 1325 1326 def visit_CallBlock(self, node: nodes.CallBlock, frame: Frame) -> None: 1327 call_frame, macro_ref = self.macro_body(node, frame) 1328 self.writeline("caller = ") 1329 self.macro_def(macro_ref, call_frame) 1330 self.start_write(frame, node) 1331 self.visit_Call(node.call, frame, forward_caller=True) 1332 self.end_write(frame) 1333 1334 def visit_FilterBlock(self, node: nodes.FilterBlock, frame: Frame) -> None: 1335 filter_frame = frame.inner() 1336 filter_frame.symbols.analyze_node(node) 1337 self.enter_frame(filter_frame) 1338 self.buffer(filter_frame) 1339 self.blockvisit(node.body, filter_frame) 1340 self.start_write(frame, node) 1341 self.visit_Filter(node.filter, filter_frame) 1342 self.end_write(frame) 1343 self.leave_frame(filter_frame) 1344 1345 def visit_With(self, node: nodes.With, frame: Frame) -> None: 1346 with_frame = frame.inner() 1347 with_frame.symbols.analyze_node(node) 1348 self.enter_frame(with_frame) 1349 for target, expr in zip(node.targets, node.values): 1350 self.newline() 1351 self.visit(target, with_frame) 1352 self.write(" = ") 1353 self.visit(expr, frame) 1354 self.blockvisit(node.body, with_frame) 1355 self.leave_frame(with_frame) 1356 1357 def visit_ExprStmt(self, node: nodes.ExprStmt, frame: Frame) -> None: 1358 self.newline(node) 1359 self.visit(node.node, frame) 1360 1361 class _FinalizeInfo(t.NamedTuple): 1362 const: t.Optional[t.Callable[..., str]] 1363 src: t.Optional[str] 1364 1365 @staticmethod 1366 def _default_finalize(value: t.Any) -> t.Any: 1367 """The default finalize function if the environment isn't 1368 configured with one. Or, if the environment has one, this is 1369 called on that function's output for constants. 1370 """ 1371 return str(value) 1372 1373 _finalize: t.Optional[_FinalizeInfo] = None 1374 1375 def _make_finalize(self) -> _FinalizeInfo: 1376 """Build the finalize function to be used on constants and at 1377 runtime. Cached so it's only created once for all output nodes. 1378 1379 Returns a ``namedtuple`` with the following attributes: 1380 1381 ``const`` 1382 A function to finalize constant data at compile time. 1383 1384 ``src`` 1385 Source code to output around nodes to be evaluated at 1386 runtime. 1387 """ 1388 if self._finalize is not None: 1389 return self._finalize 1390 1391 finalize: t.Optional[t.Callable[..., t.Any]] 1392 finalize = default = self._default_finalize 1393 src = None 1394 1395 if self.environment.finalize: 1396 src = "environment.finalize(" 1397 env_finalize = self.environment.finalize 1398 pass_arg = { 1399 _PassArg.context: "context", 1400 _PassArg.eval_context: "context.eval_ctx", 1401 _PassArg.environment: "environment", 1402 }.get( 1403 _PassArg.from_obj(env_finalize) # type: ignore 1404 ) 1405 finalize = None 1406 1407 if pass_arg is None: 1408 1409 def finalize(value: t.Any) -> t.Any: # noqa: F811 1410 return default(env_finalize(value)) 1411 1412 else: 1413 src = f"{src}{pass_arg}, " 1414 1415 if pass_arg == "environment": 1416 1417 def finalize(value: t.Any) -> t.Any: # noqa: F811 1418 return default(env_finalize(self.environment, value)) 1419 1420 self._finalize = self._FinalizeInfo(finalize, src) 1421 return self._finalize 1422 1423 def _output_const_repr(self, group: t.Iterable[t.Any]) -> str: 1424 """Given a group of constant values converted from ``Output`` 1425 child nodes, produce a string to write to the template module 1426 source. 1427 """ 1428 return repr(concat(group)) 1429 1430 def _output_child_to_const( 1431 self, node: nodes.Expr, frame: Frame, finalize: _FinalizeInfo 1432 ) -> str: 1433 """Try to optimize a child of an ``Output`` node by trying to 1434 convert it to constant, finalized data at compile time. 1435 1436 If :exc:`Impossible` is raised, the node is not constant and 1437 will be evaluated at runtime. Any other exception will also be 1438 evaluated at runtime for easier debugging. 1439 """ 1440 const = node.as_const(frame.eval_ctx) 1441 1442 if frame.eval_ctx.autoescape: 1443 const = escape(const) 1444 1445 # Template data doesn't go through finalize. 1446 if isinstance(node, nodes.TemplateData): 1447 return str(const) 1448 1449 return finalize.const(const) # type: ignore 1450 1451 def _output_child_pre( 1452 self, node: nodes.Expr, frame: Frame, finalize: _FinalizeInfo 1453 ) -> None: 1454 """Output extra source code before visiting a child of an 1455 ``Output`` node. 1456 """ 1457 if frame.eval_ctx.volatile: 1458 self.write("(escape if context.eval_ctx.autoescape else str)(") 1459 elif frame.eval_ctx.autoescape: 1460 self.write("escape(") 1461 else: 1462 self.write("str(") 1463 1464 if finalize.src is not None: 1465 self.write(finalize.src) 1466 1467 def _output_child_post( 1468 self, node: nodes.Expr, frame: Frame, finalize: _FinalizeInfo 1469 ) -> None: 1470 """Output extra source code after visiting a child of an 1471 ``Output`` node. 1472 """ 1473 self.write(")") 1474 1475 if finalize.src is not None: 1476 self.write(")") 1477 1478 def visit_Output(self, node: nodes.Output, frame: Frame) -> None: 1479 # If an extends is active, don't render outside a block. 1480 if frame.require_output_check: 1481 # A top-level extends is known to exist at compile time. 1482 if self.has_known_extends: 1483 return 1484 1485 self.writeline("if parent_template is None:") 1486 self.indent() 1487 1488 finalize = self._make_finalize() 1489 body: t.List[t.Union[t.List[t.Any], nodes.Expr]] = [] 1490 1491 # Evaluate constants at compile time if possible. Each item in 1492 # body will be either a list of static data or a node to be 1493 # evaluated at runtime. 1494 for child in node.nodes: 1495 try: 1496 if not ( 1497 # If the finalize function requires runtime context, 1498 # constants can't be evaluated at compile time. 1499 finalize.const 1500 # Unless it's basic template data that won't be 1501 # finalized anyway. 1502 or isinstance(child, nodes.TemplateData) 1503 ): 1504 raise nodes.Impossible() 1505 1506 const = self._output_child_to_const(child, frame, finalize) 1507 except (nodes.Impossible, Exception): 1508 # The node was not constant and needs to be evaluated at 1509 # runtime. Or another error was raised, which is easier 1510 # to debug at runtime. 1511 body.append(child) 1512 continue 1513 1514 if body and isinstance(body[-1], list): 1515 body[-1].append(const) 1516 else: 1517 body.append([const]) 1518 1519 if frame.buffer is not None: 1520 if len(body) == 1: 1521 self.writeline(f"{frame.buffer}.append(") 1522 else: 1523 self.writeline(f"{frame.buffer}.extend((") 1524 1525 self.indent() 1526 1527 for item in body: 1528 if isinstance(item, list): 1529 # A group of constant data to join and output. 1530 val = self._output_const_repr(item) 1531 1532 if frame.buffer is None: 1533 self.writeline("yield " + val) 1534 else: 1535 self.writeline(val + ",") 1536 else: 1537 if frame.buffer is None: 1538 self.writeline("yield ", item) 1539 else: 1540 self.newline(item) 1541 1542 # A node to be evaluated at runtime. 1543 self._output_child_pre(item, frame, finalize) 1544 self.visit(item, frame) 1545 self._output_child_post(item, frame, finalize) 1546 1547 if frame.buffer is not None: 1548 self.write(",") 1549 1550 if frame.buffer is not None: 1551 self.outdent() 1552 self.writeline(")" if len(body) == 1 else "))") 1553 1554 if frame.require_output_check: 1555 self.outdent() 1556 1557 def visit_Assign(self, node: nodes.Assign, frame: Frame) -> None: 1558 self.push_assign_tracking() 1559 self.newline(node) 1560 self.visit(node.target, frame) 1561 self.write(" = ") 1562 self.visit(node.node, frame) 1563 self.pop_assign_tracking(frame) 1564 1565 def visit_AssignBlock(self, node: nodes.AssignBlock, frame: Frame) -> None: 1566 self.push_assign_tracking() 1567 block_frame = frame.inner() 1568 # This is a special case. Since a set block always captures we 1569 # will disable output checks. This way one can use set blocks 1570 # toplevel even in extended templates. 1571 block_frame.require_output_check = False 1572 block_frame.symbols.analyze_node(node) 1573 self.enter_frame(block_frame) 1574 self.buffer(block_frame) 1575 self.blockvisit(node.body, block_frame) 1576 self.newline(node) 1577 self.visit(node.target, frame) 1578 self.write(" = (Markup if context.eval_ctx.autoescape else identity)(") 1579 if node.filter is not None: 1580 self.visit_Filter(node.filter, block_frame) 1581 else: 1582 self.write(f"concat({block_frame.buffer})") 1583 self.write(")") 1584 self.pop_assign_tracking(frame) 1585 self.leave_frame(block_frame) 1586 1587 # -- Expression Visitors 1588 1589 def visit_Name(self, node: nodes.Name, frame: Frame) -> None: 1590 if node.ctx == "store" and ( 1591 frame.toplevel or frame.loop_frame or frame.block_frame 1592 ): 1593 if self._assign_stack: 1594 self._assign_stack[-1].add(node.name) 1595 ref = frame.symbols.ref(node.name) 1596 1597 # If we are looking up a variable we might have to deal with the 1598 # case where it's undefined. We can skip that case if the load 1599 # instruction indicates a parameter which are always defined. 1600 if node.ctx == "load": 1601 load = frame.symbols.find_load(ref) 1602 if not ( 1603 load is not None 1604 and load[0] == VAR_LOAD_PARAMETER 1605 and not self.parameter_is_undeclared(ref) 1606 ): 1607 self.write( 1608 f"(undefined(name={node.name!r}) if {ref} is missing else {ref})" 1609 ) 1610 return 1611 1612 self.write(ref) 1613 1614 def visit_NSRef(self, node: nodes.NSRef, frame: Frame) -> None: 1615 # NSRefs can only be used to store values; since they use the normal 1616 # `foo.bar` notation they will be parsed as a normal attribute access 1617 # when used anywhere but in a `set` context 1618 ref = frame.symbols.ref(node.name) 1619 self.writeline(f"if not isinstance({ref}, Namespace):") 1620 self.indent() 1621 self.writeline( 1622 "raise TemplateRuntimeError" 1623 '("cannot assign attribute on non-namespace object")' 1624 ) 1625 self.outdent() 1626 self.writeline(f"{ref}[{node.attr!r}]") 1627 1628 def visit_Const(self, node: nodes.Const, frame: Frame) -> None: 1629 val = node.as_const(frame.eval_ctx) 1630 if isinstance(val, float): 1631 self.write(str(val)) 1632 else: 1633 self.write(repr(val)) 1634 1635 def visit_TemplateData(self, node: nodes.TemplateData, frame: Frame) -> None: 1636 try: 1637 self.write(repr(node.as_const(frame.eval_ctx))) 1638 except nodes.Impossible: 1639 self.write( 1640 f"(Markup if context.eval_ctx.autoescape else identity)({node.data!r})" 1641 ) 1642 1643 def visit_Tuple(self, node: nodes.Tuple, frame: Frame) -> None: 1644 self.write("(") 1645 idx = -1 1646 for idx, item in enumerate(node.items): 1647 if idx: 1648 self.write(", ") 1649 self.visit(item, frame) 1650 self.write(",)" if idx == 0 else ")") 1651 1652 def visit_List(self, node: nodes.List, frame: Frame) -> None: 1653 self.write("[") 1654 for idx, item in enumerate(node.items): 1655 if idx: 1656 self.write(", ") 1657 self.visit(item, frame) 1658 self.write("]") 1659 1660 def visit_Dict(self, node: nodes.Dict, frame: Frame) -> None: 1661 self.write("{") 1662 for idx, item in enumerate(node.items): 1663 if idx: 1664 self.write(", ") 1665 self.visit(item.key, frame) 1666 self.write(": ") 1667 self.visit(item.value, frame) 1668 self.write("}") 1669 1670 visit_Add = _make_binop("+") 1671 visit_Sub = _make_binop("-") 1672 visit_Mul = _make_binop("*") 1673 visit_Div = _make_binop("/") 1674 visit_FloorDiv = _make_binop("//") 1675 visit_Pow = _make_binop("**") 1676 visit_Mod = _make_binop("%") 1677 visit_And = _make_binop("and") 1678 visit_Or = _make_binop("or") 1679 visit_Pos = _make_unop("+") 1680 visit_Neg = _make_unop("-") 1681 visit_Not = _make_unop("not ") 1682 1683 @optimizeconst 1684 def visit_Concat(self, node: nodes.Concat, frame: Frame) -> None: 1685 if frame.eval_ctx.volatile: 1686 func_name = "(markup_join if context.eval_ctx.volatile else str_join)" 1687 elif frame.eval_ctx.autoescape: 1688 func_name = "markup_join" 1689 else: 1690 func_name = "str_join" 1691 self.write(f"{func_name}((") 1692 for arg in node.nodes: 1693 self.visit(arg, frame) 1694 self.write(", ") 1695 self.write("))") 1696 1697 @optimizeconst 1698 def visit_Compare(self, node: nodes.Compare, frame: Frame) -> None: 1699 self.write("(") 1700 self.visit(node.expr, frame) 1701 for op in node.ops: 1702 self.visit(op, frame) 1703 self.write(")") 1704 1705 def visit_Operand(self, node: nodes.Operand, frame: Frame) -> None: 1706 self.write(f" {operators[node.op]} ") 1707 self.visit(node.expr, frame) 1708 1709 @optimizeconst 1710 def visit_Getattr(self, node: nodes.Getattr, frame: Frame) -> None: 1711 if self.environment.is_async: 1712 self.write("(await auto_await(") 1713 1714 self.write("environment.getattr(") 1715 self.visit(node.node, frame) 1716 self.write(f", {node.attr!r})") 1717 1718 if self.environment.is_async: 1719 self.write("))") 1720 1721 @optimizeconst 1722 def visit_Getitem(self, node: nodes.Getitem, frame: Frame) -> None: 1723 # slices bypass the environment getitem method. 1724 if isinstance(node.arg, nodes.Slice): 1725 self.visit(node.node, frame) 1726 self.write("[") 1727 self.visit(node.arg, frame) 1728 self.write("]") 1729 else: 1730 if self.environment.is_async: 1731 self.write("(await auto_await(") 1732 1733 self.write("environment.getitem(") 1734 self.visit(node.node, frame) 1735 self.write(", ") 1736 self.visit(node.arg, frame) 1737 self.write(")") 1738 1739 if self.environment.is_async: 1740 self.write("))") 1741 1742 def visit_Slice(self, node: nodes.Slice, frame: Frame) -> None: 1743 if node.start is not None: 1744 self.visit(node.start, frame) 1745 self.write(":") 1746 if node.stop is not None: 1747 self.visit(node.stop, frame) 1748 if node.step is not None: 1749 self.write(":") 1750 self.visit(node.step, frame) 1751 1752 @contextmanager 1753 def _filter_test_common( 1754 self, node: t.Union[nodes.Filter, nodes.Test], frame: Frame, is_filter: bool 1755 ) -> t.Iterator[None]: 1756 if self.environment.is_async: 1757 self.write("(await auto_await(") 1758 1759 if is_filter: 1760 self.write(f"{self.filters[node.name]}(") 1761 func = self.environment.filters.get(node.name) 1762 else: 1763 self.write(f"{self.tests[node.name]}(") 1764 func = self.environment.tests.get(node.name) 1765 1766 # When inside an If or CondExpr frame, allow the filter to be 1767 # undefined at compile time and only raise an error if it's 1768 # actually called at runtime. See pull_dependencies. 1769 if func is None and not frame.soft_frame: 1770 type_name = "filter" if is_filter else "test" 1771 self.fail(f"No {type_name} named {node.name!r}.", node.lineno) 1772 1773 pass_arg = { 1774 _PassArg.context: "context", 1775 _PassArg.eval_context: "context.eval_ctx", 1776 _PassArg.environment: "environment", 1777 }.get( 1778 _PassArg.from_obj(func) # type: ignore 1779 ) 1780 1781 if pass_arg is not None: 1782 self.write(f"{pass_arg}, ") 1783 1784 # Back to the visitor function to handle visiting the target of 1785 # the filter or test. 1786 yield 1787 1788 self.signature(node, frame) 1789 self.write(")") 1790 1791 if self.environment.is_async: 1792 self.write("))") 1793 1794 @optimizeconst 1795 def visit_Filter(self, node: nodes.Filter, frame: Frame) -> None: 1796 with self._filter_test_common(node, frame, True): 1797 # if the filter node is None we are inside a filter block 1798 # and want to write to the current buffer 1799 if node.node is not None: 1800 self.visit(node.node, frame) 1801 elif frame.eval_ctx.volatile: 1802 self.write( 1803 f"(Markup(concat({frame.buffer}))" 1804 f" if context.eval_ctx.autoescape else concat({frame.buffer}))" 1805 ) 1806 elif frame.eval_ctx.autoescape: 1807 self.write(f"Markup(concat({frame.buffer}))") 1808 else: 1809 self.write(f"concat({frame.buffer})") 1810 1811 @optimizeconst 1812 def visit_Test(self, node: nodes.Test, frame: Frame) -> None: 1813 with self._filter_test_common(node, frame, False): 1814 self.visit(node.node, frame) 1815 1816 @optimizeconst 1817 def visit_CondExpr(self, node: nodes.CondExpr, frame: Frame) -> None: 1818 frame = frame.soft() 1819 1820 def write_expr2() -> None: 1821 if node.expr2 is not None: 1822 self.visit(node.expr2, frame) 1823 return 1824 1825 self.write( 1826 f'cond_expr_undefined("the inline if-expression on' 1827 f" {self.position(node)} evaluated to false and no else" 1828 f' section was defined.")' 1829 ) 1830 1831 self.write("(") 1832 self.visit(node.expr1, frame) 1833 self.write(" if ") 1834 self.visit(node.test, frame) 1835 self.write(" else ") 1836 write_expr2() 1837 self.write(")") 1838 1839 @optimizeconst 1840 def visit_Call( 1841 self, node: nodes.Call, frame: Frame, forward_caller: bool = False 1842 ) -> None: 1843 if self.environment.is_async: 1844 self.write("(await auto_await(") 1845 if self.environment.sandboxed: 1846 self.write("environment.call(context, ") 1847 else: 1848 self.write("context.call(") 1849 self.visit(node.node, frame) 1850 extra_kwargs = {"caller": "caller"} if forward_caller else None 1851 loop_kwargs = {"_loop_vars": "_loop_vars"} if frame.loop_frame else {} 1852 block_kwargs = {"_block_vars": "_block_vars"} if frame.block_frame else {} 1853 if extra_kwargs: 1854 extra_kwargs.update(loop_kwargs, **block_kwargs) 1855 elif loop_kwargs or block_kwargs: 1856 extra_kwargs = dict(loop_kwargs, **block_kwargs) 1857 self.signature(node, frame, extra_kwargs) 1858 self.write(")") 1859 if self.environment.is_async: 1860 self.write("))") 1861 1862 def visit_Keyword(self, node: nodes.Keyword, frame: Frame) -> None: 1863 self.write(node.key + "=") 1864 self.visit(node.value, frame) 1865 1866 # -- Unused nodes for extensions 1867 1868 def visit_MarkSafe(self, node: nodes.MarkSafe, frame: Frame) -> None: 1869 self.write("Markup(") 1870 self.visit(node.expr, frame) 1871 self.write(")") 1872 1873 def visit_MarkSafeIfAutoescape( 1874 self, node: nodes.MarkSafeIfAutoescape, frame: Frame 1875 ) -> None: 1876 self.write("(Markup if context.eval_ctx.autoescape else identity)(") 1877 self.visit(node.expr, frame) 1878 self.write(")") 1879 1880 def visit_EnvironmentAttribute( 1881 self, node: nodes.EnvironmentAttribute, frame: Frame 1882 ) -> None: 1883 self.write("environment." + node.name) 1884 1885 def visit_ExtensionAttribute( 1886 self, node: nodes.ExtensionAttribute, frame: Frame 1887 ) -> None: 1888 self.write(f"environment.extensions[{node.identifier!r}].{node.name}") 1889 1890 def visit_ImportedName(self, node: nodes.ImportedName, frame: Frame) -> None: 1891 self.write(self.import_aliases[node.importname]) 1892 1893 def visit_InternalName(self, node: nodes.InternalName, frame: Frame) -> None: 1894 self.write(node.name) 1895 1896 def visit_ContextReference( 1897 self, node: nodes.ContextReference, frame: Frame 1898 ) -> None: 1899 self.write("context") 1900 1901 def visit_DerivedContextReference( 1902 self, node: nodes.DerivedContextReference, frame: Frame 1903 ) -> None: 1904 self.write(self.derive_context(frame)) 1905 1906 def visit_Continue(self, node: nodes.Continue, frame: Frame) -> None: 1907 self.writeline("continue", node) 1908 1909 def visit_Break(self, node: nodes.Break, frame: Frame) -> None: 1910 self.writeline("break", node) 1911 1912 def visit_Scope(self, node: nodes.Scope, frame: Frame) -> None: 1913 scope_frame = frame.inner() 1914 scope_frame.symbols.analyze_node(node) 1915 self.enter_frame(scope_frame) 1916 self.blockvisit(node.body, scope_frame) 1917 self.leave_frame(scope_frame) 1918 1919 def visit_OverlayScope(self, node: nodes.OverlayScope, frame: Frame) -> None: 1920 ctx = self.temporary_identifier() 1921 self.writeline(f"{ctx} = {self.derive_context(frame)}") 1922 self.writeline(f"{ctx}.vars = ") 1923 self.visit(node.context, frame) 1924 self.push_context_reference(ctx) 1925 1926 scope_frame = frame.inner(isolated=True) 1927 scope_frame.symbols.analyze_node(node) 1928 self.enter_frame(scope_frame) 1929 self.blockvisit(node.body, scope_frame) 1930 self.leave_frame(scope_frame) 1931 self.pop_context_reference() 1932 1933 def visit_EvalContextModifier( 1934 self, node: nodes.EvalContextModifier, frame: Frame 1935 ) -> None: 1936 for keyword in node.options: 1937 self.writeline(f"context.eval_ctx.{keyword.key} = ") 1938 self.visit(keyword.value, frame) 1939 try: 1940 val = keyword.value.as_const(frame.eval_ctx) 1941 except nodes.Impossible: 1942 frame.eval_ctx.volatile = True 1943 else: 1944 setattr(frame.eval_ctx, keyword.key, val) 1945 1946 def visit_ScopedEvalContextModifier( 1947 self, node: nodes.ScopedEvalContextModifier, frame: Frame 1948 ) -> None: 1949 old_ctx_name = self.temporary_identifier() 1950 saved_ctx = frame.eval_ctx.save() 1951 self.writeline(f"{old_ctx_name} = context.eval_ctx.save()") 1952 self.visit_EvalContextModifier(node, frame) 1953 for child in node.body: 1954 self.visit(child, frame) 1955 frame.eval_ctx.revert(saved_ctx) 1956 self.writeline(f"context.eval_ctx.revert({old_ctx_name})") 1957