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Diffstat (limited to 'src/jinja2/nodes.py')
| -rw-r--r-- | src/jinja2/nodes.py | 1204 |
1 files changed, 1204 insertions, 0 deletions
diff --git a/src/jinja2/nodes.py b/src/jinja2/nodes.py new file mode 100644 index 0000000..b2f88d9 --- /dev/null +++ b/src/jinja2/nodes.py @@ -0,0 +1,1204 @@ +"""AST nodes generated by the parser for the compiler. Also provides +some node tree helper functions used by the parser and compiler in order +to normalize nodes. +""" +import inspect +import operator +import typing as t +from collections import deque + +from markupsafe import Markup + +from .utils import _PassArg + +if t.TYPE_CHECKING: + import typing_extensions as te + from .environment import Environment + +_NodeBound = t.TypeVar("_NodeBound", bound="Node") + +_binop_to_func: t.Dict[str, t.Callable[[t.Any, t.Any], t.Any]] = { + "*": operator.mul, + "/": operator.truediv, + "//": operator.floordiv, + "**": operator.pow, + "%": operator.mod, + "+": operator.add, + "-": operator.sub, +} + +_uaop_to_func: t.Dict[str, t.Callable[[t.Any], t.Any]] = { + "not": operator.not_, + "+": operator.pos, + "-": operator.neg, +} + +_cmpop_to_func: t.Dict[str, t.Callable[[t.Any, t.Any], t.Any]] = { + "eq": operator.eq, + "ne": operator.ne, + "gt": operator.gt, + "gteq": operator.ge, + "lt": operator.lt, + "lteq": operator.le, + "in": lambda a, b: a in b, + "notin": lambda a, b: a not in b, +} + + +class Impossible(Exception): + """Raised if the node could not perform a requested action.""" + + +class NodeType(type): + """A metaclass for nodes that handles the field and attribute + inheritance. fields and attributes from the parent class are + automatically forwarded to the child.""" + + def __new__(mcs, name, bases, d): # type: ignore + for attr in "fields", "attributes": + storage = [] + storage.extend(getattr(bases[0] if bases else object, attr, ())) + storage.extend(d.get(attr, ())) + assert len(bases) <= 1, "multiple inheritance not allowed" + assert len(storage) == len(set(storage)), "layout conflict" + d[attr] = tuple(storage) + d.setdefault("abstract", False) + return type.__new__(mcs, name, bases, d) + + +class EvalContext: + """Holds evaluation time information. Custom attributes can be attached + to it in extensions. + """ + + def __init__( + self, environment: "Environment", template_name: t.Optional[str] = None + ) -> None: + self.environment = environment + if callable(environment.autoescape): + self.autoescape = environment.autoescape(template_name) + else: + self.autoescape = environment.autoescape + self.volatile = False + + def save(self) -> t.Mapping[str, t.Any]: + return self.__dict__.copy() + + def revert(self, old: t.Mapping[str, t.Any]) -> None: + self.__dict__.clear() + self.__dict__.update(old) + + +def get_eval_context(node: "Node", ctx: t.Optional[EvalContext]) -> EvalContext: + if ctx is None: + if node.environment is None: + raise RuntimeError( + "if no eval context is passed, the node must have an" + " attached environment." + ) + return EvalContext(node.environment) + return ctx + + +class Node(metaclass=NodeType): + """Baseclass for all Jinja nodes. There are a number of nodes available + of different types. There are four major types: + + - :class:`Stmt`: statements + - :class:`Expr`: expressions + - :class:`Helper`: helper nodes + - :class:`Template`: the outermost wrapper node + + All nodes have fields and attributes. Fields may be other nodes, lists, + or arbitrary values. Fields are passed to the constructor as regular + positional arguments, attributes as keyword arguments. Each node has + two attributes: `lineno` (the line number of the node) and `environment`. + The `environment` attribute is set at the end of the parsing process for + all nodes automatically. + """ + + fields: t.Tuple[str, ...] = () + attributes: t.Tuple[str, ...] = ("lineno", "environment") + abstract = True + + lineno: int + environment: t.Optional["Environment"] + + def __init__(self, *fields: t.Any, **attributes: t.Any) -> None: + if self.abstract: + raise TypeError("abstract nodes are not instantiable") + if fields: + if len(fields) != len(self.fields): + if not self.fields: + raise TypeError(f"{type(self).__name__!r} takes 0 arguments") + raise TypeError( + f"{type(self).__name__!r} takes 0 or {len(self.fields)}" + f" argument{'s' if len(self.fields) != 1 else ''}" + ) + for name, arg in zip(self.fields, fields): + setattr(self, name, arg) + for attr in self.attributes: + setattr(self, attr, attributes.pop(attr, None)) + if attributes: + raise TypeError(f"unknown attribute {next(iter(attributes))!r}") + + def iter_fields( + self, + exclude: t.Optional[t.Container[str]] = None, + only: t.Optional[t.Container[str]] = None, + ) -> t.Iterator[t.Tuple[str, t.Any]]: + """This method iterates over all fields that are defined and yields + ``(key, value)`` tuples. Per default all fields are returned, but + it's possible to limit that to some fields by providing the `only` + parameter or to exclude some using the `exclude` parameter. Both + should be sets or tuples of field names. + """ + for name in self.fields: + if ( + (exclude is None and only is None) + or (exclude is not None and name not in exclude) + or (only is not None and name in only) + ): + try: + yield name, getattr(self, name) + except AttributeError: + pass + + def iter_child_nodes( + self, + exclude: t.Optional[t.Container[str]] = None, + only: t.Optional[t.Container[str]] = None, + ) -> t.Iterator["Node"]: + """Iterates over all direct child nodes of the node. This iterates + over all fields and yields the values of they are nodes. If the value + of a field is a list all the nodes in that list are returned. + """ + for _, item in self.iter_fields(exclude, only): + if isinstance(item, list): + for n in item: + if isinstance(n, Node): + yield n + elif isinstance(item, Node): + yield item + + def find(self, node_type: t.Type[_NodeBound]) -> t.Optional[_NodeBound]: + """Find the first node of a given type. If no such node exists the + return value is `None`. + """ + for result in self.find_all(node_type): + return result + + return None + + def find_all( + self, node_type: t.Union[t.Type[_NodeBound], t.Tuple[t.Type[_NodeBound], ...]] + ) -> t.Iterator[_NodeBound]: + """Find all the nodes of a given type. If the type is a tuple, + the check is performed for any of the tuple items. + """ + for child in self.iter_child_nodes(): + if isinstance(child, node_type): + yield child # type: ignore + yield from child.find_all(node_type) + + def set_ctx(self, ctx: str) -> "Node": + """Reset the context of a node and all child nodes. Per default the + parser will all generate nodes that have a 'load' context as it's the + most common one. This method is used in the parser to set assignment + targets and other nodes to a store context. + """ + todo = deque([self]) + while todo: + node = todo.popleft() + if "ctx" in node.fields: + node.ctx = ctx # type: ignore + todo.extend(node.iter_child_nodes()) + return self + + def set_lineno(self, lineno: int, override: bool = False) -> "Node": + """Set the line numbers of the node and children.""" + todo = deque([self]) + while todo: + node = todo.popleft() + if "lineno" in node.attributes: + if node.lineno is None or override: + node.lineno = lineno + todo.extend(node.iter_child_nodes()) + return self + + def set_environment(self, environment: "Environment") -> "Node": + """Set the environment for all nodes.""" + todo = deque([self]) + while todo: + node = todo.popleft() + node.environment = environment + todo.extend(node.iter_child_nodes()) + return self + + def __eq__(self, other: t.Any) -> bool: + if type(self) is not type(other): + return NotImplemented + + return tuple(self.iter_fields()) == tuple(other.iter_fields()) + + __hash__ = object.__hash__ + + def __repr__(self) -> str: + args_str = ", ".join(f"{a}={getattr(self, a, None)!r}" for a in self.fields) + return f"{type(self).__name__}({args_str})" + + def dump(self) -> str: + def _dump(node: t.Union[Node, t.Any]) -> None: + if not isinstance(node, Node): + buf.append(repr(node)) + return + + buf.append(f"nodes.{type(node).__name__}(") + if not node.fields: + buf.append(")") + return + for idx, field in enumerate(node.fields): + if idx: + buf.append(", ") + value = getattr(node, field) + if isinstance(value, list): + buf.append("[") + for idx, item in enumerate(value): + if idx: + buf.append(", ") + _dump(item) + buf.append("]") + else: + _dump(value) + buf.append(")") + + buf: t.List[str] = [] + _dump(self) + return "".join(buf) + + +class Stmt(Node): + """Base node for all statements.""" + + abstract = True + + +class Helper(Node): + """Nodes that exist in a specific context only.""" + + abstract = True + + +class Template(Node): + """Node that represents a template. This must be the outermost node that + is passed to the compiler. + """ + + fields = ("body",) + body: t.List[Node] + + +class Output(Stmt): + """A node that holds multiple expressions which are then printed out. + This is used both for the `print` statement and the regular template data. + """ + + fields = ("nodes",) + nodes: t.List["Expr"] + + +class Extends(Stmt): + """Represents an extends statement.""" + + fields = ("template",) + template: "Expr" + + +class For(Stmt): + """The for loop. `target` is the target for the iteration (usually a + :class:`Name` or :class:`Tuple`), `iter` the iterable. `body` is a list + of nodes that are used as loop-body, and `else_` a list of nodes for the + `else` block. If no else node exists it has to be an empty list. + + For filtered nodes an expression can be stored as `test`, otherwise `None`. + """ + + fields = ("target", "iter", "body", "else_", "test", "recursive") + target: Node + iter: Node + body: t.List[Node] + else_: t.List[Node] + test: t.Optional[Node] + recursive: bool + + +class If(Stmt): + """If `test` is true, `body` is rendered, else `else_`.""" + + fields = ("test", "body", "elif_", "else_") + test: Node + body: t.List[Node] + elif_: t.List["If"] + else_: t.List[Node] + + +class Macro(Stmt): + """A macro definition. `name` is the name of the macro, `args` a list of + arguments and `defaults` a list of defaults if there are any. `body` is + a list of nodes for the macro body. + """ + + fields = ("name", "args", "defaults", "body") + name: str + args: t.List["Name"] + defaults: t.List["Expr"] + body: t.List[Node] + + +class CallBlock(Stmt): + """Like a macro without a name but a call instead. `call` is called with + the unnamed macro as `caller` argument this node holds. + """ + + fields = ("call", "args", "defaults", "body") + call: "Call" + args: t.List["Name"] + defaults: t.List["Expr"] + body: t.List[Node] + + +class FilterBlock(Stmt): + """Node for filter sections.""" + + fields = ("body", "filter") + body: t.List[Node] + filter: "Filter" + + +class With(Stmt): + """Specific node for with statements. In older versions of Jinja the + with statement was implemented on the base of the `Scope` node instead. + + .. versionadded:: 2.9.3 + """ + + fields = ("targets", "values", "body") + targets: t.List["Expr"] + values: t.List["Expr"] + body: t.List[Node] + + +class Block(Stmt): + """A node that represents a block. + + .. versionchanged:: 3.0.0 + the `required` field was added. + """ + + fields = ("name", "body", "scoped", "required") + name: str + body: t.List[Node] + scoped: bool + required: bool + + +class Include(Stmt): + """A node that represents the include tag.""" + + fields = ("template", "with_context", "ignore_missing") + template: "Expr" + with_context: bool + ignore_missing: bool + + +class Import(Stmt): + """A node that represents the import tag.""" + + fields = ("template", "target", "with_context") + template: "Expr" + target: str + with_context: bool + + +class FromImport(Stmt): + """A node that represents the from import tag. It's important to not + pass unsafe names to the name attribute. The compiler translates the + attribute lookups directly into getattr calls and does *not* use the + subscript callback of the interface. As exported variables may not + start with double underscores (which the parser asserts) this is not a + problem for regular Jinja code, but if this node is used in an extension + extra care must be taken. + + The list of names may contain tuples if aliases are wanted. + """ + + fields = ("template", "names", "with_context") + template: "Expr" + names: t.List[t.Union[str, t.Tuple[str, str]]] + with_context: bool + + +class ExprStmt(Stmt): + """A statement that evaluates an expression and discards the result.""" + + fields = ("node",) + node: Node + + +class Assign(Stmt): + """Assigns an expression to a target.""" + + fields = ("target", "node") + target: "Expr" + node: Node + + +class AssignBlock(Stmt): + """Assigns a block to a target.""" + + fields = ("target", "filter", "body") + target: "Expr" + filter: t.Optional["Filter"] + body: t.List[Node] + + +class Expr(Node): + """Baseclass for all expressions.""" + + abstract = True + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + """Return the value of the expression as constant or raise + :exc:`Impossible` if this was not possible. + + An :class:`EvalContext` can be provided, if none is given + a default context is created which requires the nodes to have + an attached environment. + + .. versionchanged:: 2.4 + the `eval_ctx` parameter was added. + """ + raise Impossible() + + def can_assign(self) -> bool: + """Check if it's possible to assign something to this node.""" + return False + + +class BinExpr(Expr): + """Baseclass for all binary expressions.""" + + fields = ("left", "right") + left: Expr + right: Expr + operator: str + abstract = True + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + + # intercepted operators cannot be folded at compile time + if ( + eval_ctx.environment.sandboxed + and self.operator in eval_ctx.environment.intercepted_binops # type: ignore + ): + raise Impossible() + f = _binop_to_func[self.operator] + try: + return f(self.left.as_const(eval_ctx), self.right.as_const(eval_ctx)) + except Exception as e: + raise Impossible() from e + + +class UnaryExpr(Expr): + """Baseclass for all unary expressions.""" + + fields = ("node",) + node: Expr + operator: str + abstract = True + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + + # intercepted operators cannot be folded at compile time + if ( + eval_ctx.environment.sandboxed + and self.operator in eval_ctx.environment.intercepted_unops # type: ignore + ): + raise Impossible() + f = _uaop_to_func[self.operator] + try: + return f(self.node.as_const(eval_ctx)) + except Exception as e: + raise Impossible() from e + + +class Name(Expr): + """Looks up a name or stores a value in a name. + The `ctx` of the node can be one of the following values: + + - `store`: store a value in the name + - `load`: load that name + - `param`: like `store` but if the name was defined as function parameter. + """ + + fields = ("name", "ctx") + name: str + ctx: str + + def can_assign(self) -> bool: + return self.name not in {"true", "false", "none", "True", "False", "None"} + + +class NSRef(Expr): + """Reference to a namespace value assignment""" + + fields = ("name", "attr") + name: str + attr: str + + def can_assign(self) -> bool: + # We don't need any special checks here; NSRef assignments have a + # runtime check to ensure the target is a namespace object which will + # have been checked already as it is created using a normal assignment + # which goes through a `Name` node. + return True + + +class Literal(Expr): + """Baseclass for literals.""" + + abstract = True + + +class Const(Literal): + """All constant values. The parser will return this node for simple + constants such as ``42`` or ``"foo"`` but it can be used to store more + complex values such as lists too. Only constants with a safe + representation (objects where ``eval(repr(x)) == x`` is true). + """ + + fields = ("value",) + value: t.Any + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + return self.value + + @classmethod + def from_untrusted( + cls, + value: t.Any, + lineno: t.Optional[int] = None, + environment: "t.Optional[Environment]" = None, + ) -> "Const": + """Return a const object if the value is representable as + constant value in the generated code, otherwise it will raise + an `Impossible` exception. + """ + from .compiler import has_safe_repr + + if not has_safe_repr(value): + raise Impossible() + return cls(value, lineno=lineno, environment=environment) + + +class TemplateData(Literal): + """A constant template string.""" + + fields = ("data",) + data: str + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> str: + eval_ctx = get_eval_context(self, eval_ctx) + if eval_ctx.volatile: + raise Impossible() + if eval_ctx.autoescape: + return Markup(self.data) + return self.data + + +class Tuple(Literal): + """For loop unpacking and some other things like multiple arguments + for subscripts. Like for :class:`Name` `ctx` specifies if the tuple + is used for loading the names or storing. + """ + + fields = ("items", "ctx") + items: t.List[Expr] + ctx: str + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Tuple[t.Any, ...]: + eval_ctx = get_eval_context(self, eval_ctx) + return tuple(x.as_const(eval_ctx) for x in self.items) + + def can_assign(self) -> bool: + for item in self.items: + if not item.can_assign(): + return False + return True + + +class List(Literal): + """Any list literal such as ``[1, 2, 3]``""" + + fields = ("items",) + items: t.List[Expr] + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.List[t.Any]: + eval_ctx = get_eval_context(self, eval_ctx) + return [x.as_const(eval_ctx) for x in self.items] + + +class Dict(Literal): + """Any dict literal such as ``{1: 2, 3: 4}``. The items must be a list of + :class:`Pair` nodes. + """ + + fields = ("items",) + items: t.List["Pair"] + + def as_const( + self, eval_ctx: t.Optional[EvalContext] = None + ) -> t.Dict[t.Any, t.Any]: + eval_ctx = get_eval_context(self, eval_ctx) + return dict(x.as_const(eval_ctx) for x in self.items) + + +class Pair(Helper): + """A key, value pair for dicts.""" + + fields = ("key", "value") + key: Expr + value: Expr + + def as_const( + self, eval_ctx: t.Optional[EvalContext] = None + ) -> t.Tuple[t.Any, t.Any]: + eval_ctx = get_eval_context(self, eval_ctx) + return self.key.as_const(eval_ctx), self.value.as_const(eval_ctx) + + +class Keyword(Helper): + """A key, value pair for keyword arguments where key is a string.""" + + fields = ("key", "value") + key: str + value: Expr + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Tuple[str, t.Any]: + eval_ctx = get_eval_context(self, eval_ctx) + return self.key, self.value.as_const(eval_ctx) + + +class CondExpr(Expr): + """A conditional expression (inline if expression). (``{{ + foo if bar else baz }}``) + """ + + fields = ("test", "expr1", "expr2") + test: Expr + expr1: Expr + expr2: t.Optional[Expr] + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + if self.test.as_const(eval_ctx): + return self.expr1.as_const(eval_ctx) + + # if we evaluate to an undefined object, we better do that at runtime + if self.expr2 is None: + raise Impossible() + + return self.expr2.as_const(eval_ctx) + + +def args_as_const( + node: t.Union["_FilterTestCommon", "Call"], eval_ctx: t.Optional[EvalContext] +) -> t.Tuple[t.List[t.Any], t.Dict[t.Any, t.Any]]: + args = [x.as_const(eval_ctx) for x in node.args] + kwargs = dict(x.as_const(eval_ctx) for x in node.kwargs) + + if node.dyn_args is not None: + try: + args.extend(node.dyn_args.as_const(eval_ctx)) + except Exception as e: + raise Impossible() from e + + if node.dyn_kwargs is not None: + try: + kwargs.update(node.dyn_kwargs.as_const(eval_ctx)) + except Exception as e: + raise Impossible() from e + + return args, kwargs + + +class _FilterTestCommon(Expr): + fields = ("node", "name", "args", "kwargs", "dyn_args", "dyn_kwargs") + node: Expr + name: str + args: t.List[Expr] + kwargs: t.List[Pair] + dyn_args: t.Optional[Expr] + dyn_kwargs: t.Optional[Expr] + abstract = True + _is_filter = True + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + + if eval_ctx.volatile: + raise Impossible() + + if self._is_filter: + env_map = eval_ctx.environment.filters + else: + env_map = eval_ctx.environment.tests + + func = env_map.get(self.name) + pass_arg = _PassArg.from_obj(func) # type: ignore + + if func is None or pass_arg is _PassArg.context: + raise Impossible() + + if eval_ctx.environment.is_async and ( + getattr(func, "jinja_async_variant", False) is True + or inspect.iscoroutinefunction(func) + ): + raise Impossible() + + args, kwargs = args_as_const(self, eval_ctx) + args.insert(0, self.node.as_const(eval_ctx)) + + if pass_arg is _PassArg.eval_context: + args.insert(0, eval_ctx) + elif pass_arg is _PassArg.environment: + args.insert(0, eval_ctx.environment) + + try: + return func(*args, **kwargs) + except Exception as e: + raise Impossible() from e + + +class Filter(_FilterTestCommon): + """Apply a filter to an expression. ``name`` is the name of the + filter, the other fields are the same as :class:`Call`. + + If ``node`` is ``None``, the filter is being used in a filter block + and is applied to the content of the block. + """ + + node: t.Optional[Expr] # type: ignore + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + if self.node is None: + raise Impossible() + + return super().as_const(eval_ctx=eval_ctx) + + +class Test(_FilterTestCommon): + """Apply a test to an expression. ``name`` is the name of the test, + the other field are the same as :class:`Call`. + + .. versionchanged:: 3.0 + ``as_const`` shares the same logic for filters and tests. Tests + check for volatile, async, and ``@pass_context`` etc. + decorators. + """ + + _is_filter = False + + +class Call(Expr): + """Calls an expression. `args` is a list of arguments, `kwargs` a list + of keyword arguments (list of :class:`Keyword` nodes), and `dyn_args` + and `dyn_kwargs` has to be either `None` or a node that is used as + node for dynamic positional (``*args``) or keyword (``**kwargs``) + arguments. + """ + + fields = ("node", "args", "kwargs", "dyn_args", "dyn_kwargs") + node: Expr + args: t.List[Expr] + kwargs: t.List[Keyword] + dyn_args: t.Optional[Expr] + dyn_kwargs: t.Optional[Expr] + + +class Getitem(Expr): + """Get an attribute or item from an expression and prefer the item.""" + + fields = ("node", "arg", "ctx") + node: Expr + arg: Expr + ctx: str + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + if self.ctx != "load": + raise Impossible() + + eval_ctx = get_eval_context(self, eval_ctx) + + try: + return eval_ctx.environment.getitem( + self.node.as_const(eval_ctx), self.arg.as_const(eval_ctx) + ) + except Exception as e: + raise Impossible() from e + + +class Getattr(Expr): + """Get an attribute or item from an expression that is a ascii-only + bytestring and prefer the attribute. + """ + + fields = ("node", "attr", "ctx") + node: Expr + attr: str + ctx: str + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + if self.ctx != "load": + raise Impossible() + + eval_ctx = get_eval_context(self, eval_ctx) + + try: + return eval_ctx.environment.getattr(self.node.as_const(eval_ctx), self.attr) + except Exception as e: + raise Impossible() from e + + +class Slice(Expr): + """Represents a slice object. This must only be used as argument for + :class:`Subscript`. + """ + + fields = ("start", "stop", "step") + start: t.Optional[Expr] + stop: t.Optional[Expr] + step: t.Optional[Expr] + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> slice: + eval_ctx = get_eval_context(self, eval_ctx) + + def const(obj: t.Optional[Expr]) -> t.Optional[t.Any]: + if obj is None: + return None + return obj.as_const(eval_ctx) + + return slice(const(self.start), const(self.stop), const(self.step)) + + +class Concat(Expr): + """Concatenates the list of expressions provided after converting + them to strings. + """ + + fields = ("nodes",) + nodes: t.List[Expr] + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> str: + eval_ctx = get_eval_context(self, eval_ctx) + return "".join(str(x.as_const(eval_ctx)) for x in self.nodes) + + +class Compare(Expr): + """Compares an expression with some other expressions. `ops` must be a + list of :class:`Operand`\\s. + """ + + fields = ("expr", "ops") + expr: Expr + ops: t.List["Operand"] + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + result = value = self.expr.as_const(eval_ctx) + + try: + for op in self.ops: + new_value = op.expr.as_const(eval_ctx) + result = _cmpop_to_func[op.op](value, new_value) + + if not result: + return False + + value = new_value + except Exception as e: + raise Impossible() from e + + return result + + +class Operand(Helper): + """Holds an operator and an expression.""" + + fields = ("op", "expr") + op: str + expr: Expr + + +class Mul(BinExpr): + """Multiplies the left with the right node.""" + + operator = "*" + + +class Div(BinExpr): + """Divides the left by the right node.""" + + operator = "/" + + +class FloorDiv(BinExpr): + """Divides the left by the right node and converts the + result into an integer by truncating. + """ + + operator = "//" + + +class Add(BinExpr): + """Add the left to the right node.""" + + operator = "+" + + +class Sub(BinExpr): + """Subtract the right from the left node.""" + + operator = "-" + + +class Mod(BinExpr): + """Left modulo right.""" + + operator = "%" + + +class Pow(BinExpr): + """Left to the power of right.""" + + operator = "**" + + +class And(BinExpr): + """Short circuited AND.""" + + operator = "and" + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + return self.left.as_const(eval_ctx) and self.right.as_const(eval_ctx) + + +class Or(BinExpr): + """Short circuited OR.""" + + operator = "or" + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> t.Any: + eval_ctx = get_eval_context(self, eval_ctx) + return self.left.as_const(eval_ctx) or self.right.as_const(eval_ctx) + + +class Not(UnaryExpr): + """Negate the expression.""" + + operator = "not" + + +class Neg(UnaryExpr): + """Make the expression negative.""" + + operator = "-" + + +class Pos(UnaryExpr): + """Make the expression positive (noop for most expressions)""" + + operator = "+" + + +# Helpers for extensions + + +class EnvironmentAttribute(Expr): + """Loads an attribute from the environment object. This is useful for + extensions that want to call a callback stored on the environment. + """ + + fields = ("name",) + name: str + + +class ExtensionAttribute(Expr): + """Returns the attribute of an extension bound to the environment. + The identifier is the identifier of the :class:`Extension`. + + This node is usually constructed by calling the + :meth:`~jinja2.ext.Extension.attr` method on an extension. + """ + + fields = ("identifier", "name") + identifier: str + name: str + + +class ImportedName(Expr): + """If created with an import name the import name is returned on node + access. For example ``ImportedName('cgi.escape')`` returns the `escape` + function from the cgi module on evaluation. Imports are optimized by the + compiler so there is no need to assign them to local variables. + """ + + fields = ("importname",) + importname: str + + +class InternalName(Expr): + """An internal name in the compiler. You cannot create these nodes + yourself but the parser provides a + :meth:`~jinja2.parser.Parser.free_identifier` method that creates + a new identifier for you. This identifier is not available from the + template and is not treated specially by the compiler. + """ + + fields = ("name",) + name: str + + def __init__(self) -> None: + raise TypeError( + "Can't create internal names. Use the " + "`free_identifier` method on a parser." + ) + + +class MarkSafe(Expr): + """Mark the wrapped expression as safe (wrap it as `Markup`).""" + + fields = ("expr",) + expr: Expr + + def as_const(self, eval_ctx: t.Optional[EvalContext] = None) -> Markup: + eval_ctx = get_eval_context(self, eval_ctx) + return Markup(self.expr.as_const(eval_ctx)) + + +class MarkSafeIfAutoescape(Expr): + """Mark the wrapped expression as safe (wrap it as `Markup`) but + only if autoescaping is active. + + .. versionadded:: 2.5 + """ + + fields = ("expr",) + expr: Expr + + def as_const( + self, eval_ctx: t.Optional[EvalContext] = None + ) -> t.Union[Markup, t.Any]: + eval_ctx = get_eval_context(self, eval_ctx) + if eval_ctx.volatile: + raise Impossible() + expr = self.expr.as_const(eval_ctx) + if eval_ctx.autoescape: + return Markup(expr) + return expr + + +class ContextReference(Expr): + """Returns the current template context. It can be used like a + :class:`Name` node, with a ``'load'`` ctx and will return the + current :class:`~jinja2.runtime.Context` object. + + Here an example that assigns the current template name to a + variable named `foo`:: + + Assign(Name('foo', ctx='store'), + Getattr(ContextReference(), 'name')) + + This is basically equivalent to using the + :func:`~jinja2.pass_context` decorator when using the high-level + API, which causes a reference to the context to be passed as the + first argument to a function. + """ + + +class DerivedContextReference(Expr): + """Return the current template context including locals. Behaves + exactly like :class:`ContextReference`, but includes local + variables, such as from a ``for`` loop. + + .. versionadded:: 2.11 + """ + + +class Continue(Stmt): + """Continue a loop.""" + + +class Break(Stmt): + """Break a loop.""" + + +class Scope(Stmt): + """An artificial scope.""" + + fields = ("body",) + body: t.List[Node] + + +class OverlayScope(Stmt): + """An overlay scope for extensions. This is a largely unoptimized scope + that however can be used to introduce completely arbitrary variables into + a sub scope from a dictionary or dictionary like object. The `context` + field has to evaluate to a dictionary object. + + Example usage:: + + OverlayScope(context=self.call_method('get_context'), + body=[...]) + + .. versionadded:: 2.10 + """ + + fields = ("context", "body") + context: Expr + body: t.List[Node] + + +class EvalContextModifier(Stmt): + """Modifies the eval context. For each option that should be modified, + a :class:`Keyword` has to be added to the :attr:`options` list. + + Example to change the `autoescape` setting:: + + EvalContextModifier(options=[Keyword('autoescape', Const(True))]) + """ + + fields = ("options",) + options: t.List[Keyword] + + +class ScopedEvalContextModifier(EvalContextModifier): + """Modifies the eval context and reverts it later. Works exactly like + :class:`EvalContextModifier` but will only modify the + :class:`~jinja2.nodes.EvalContext` for nodes in the :attr:`body`. + """ + + fields = ("body",) + body: t.List[Node] + + +# make sure nobody creates custom nodes +def _failing_new(*args: t.Any, **kwargs: t.Any) -> "te.NoReturn": + raise TypeError("can't create custom node types") + + +NodeType.__new__ = staticmethod(_failing_new) # type: ignore +del _failing_new |