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- import typing as t
- from . import nodes
- from .visitor import NodeVisitor
- VAR_LOAD_PARAMETER = "param"
- VAR_LOAD_RESOLVE = "resolve"
- VAR_LOAD_ALIAS = "alias"
- VAR_LOAD_UNDEFINED = "undefined"
- def find_symbols(
- nodes: t.Iterable[nodes.Node], parent_symbols: t.Optional["Symbols"] = None
- ) -> "Symbols":
- sym = Symbols(parent=parent_symbols)
- visitor = FrameSymbolVisitor(sym)
- for node in nodes:
- visitor.visit(node)
- return sym
- def symbols_for_node(
- node: nodes.Node, parent_symbols: t.Optional["Symbols"] = None
- ) -> "Symbols":
- sym = Symbols(parent=parent_symbols)
- sym.analyze_node(node)
- return sym
- class Symbols:
- def __init__(
- self, parent: t.Optional["Symbols"] = None, level: t.Optional[int] = None
- ) -> None:
- if level is None:
- if parent is None:
- level = 0
- else:
- level = parent.level + 1
- self.level: int = level
- self.parent = parent
- self.refs: t.Dict[str, str] = {}
- self.loads: t.Dict[str, t.Any] = {}
- self.stores: t.Set[str] = set()
- def analyze_node(self, node: nodes.Node, **kwargs: t.Any) -> None:
- visitor = RootVisitor(self)
- visitor.visit(node, **kwargs)
- def _define_ref(
- self, name: str, load: t.Optional[t.Tuple[str, t.Optional[str]]] = None
- ) -> str:
- ident = f"l_{self.level}_{name}"
- self.refs[name] = ident
- if load is not None:
- self.loads[ident] = load
- return ident
- def find_load(self, target: str) -> t.Optional[t.Any]:
- if target in self.loads:
- return self.loads[target]
- if self.parent is not None:
- return self.parent.find_load(target)
- return None
- def find_ref(self, name: str) -> t.Optional[str]:
- if name in self.refs:
- return self.refs[name]
- if self.parent is not None:
- return self.parent.find_ref(name)
- return None
- def ref(self, name: str) -> str:
- rv = self.find_ref(name)
- if rv is None:
- raise AssertionError(
- "Tried to resolve a name to a reference that was"
- f" unknown to the frame ({name!r})"
- )
- return rv
- def copy(self) -> "Symbols":
- rv = t.cast(Symbols, object.__new__(self.__class__))
- rv.__dict__.update(self.__dict__)
- rv.refs = self.refs.copy()
- rv.loads = self.loads.copy()
- rv.stores = self.stores.copy()
- return rv
- def store(self, name: str) -> None:
- self.stores.add(name)
- # If we have not see the name referenced yet, we need to figure
- # out what to set it to.
- if name not in self.refs:
- # If there is a parent scope we check if the name has a
- # reference there. If it does it means we might have to alias
- # to a variable there.
- if self.parent is not None:
- outer_ref = self.parent.find_ref(name)
- if outer_ref is not None:
- self._define_ref(name, load=(VAR_LOAD_ALIAS, outer_ref))
- return
- # Otherwise we can just set it to undefined.
- self._define_ref(name, load=(VAR_LOAD_UNDEFINED, None))
- def declare_parameter(self, name: str) -> str:
- self.stores.add(name)
- return self._define_ref(name, load=(VAR_LOAD_PARAMETER, None))
- def load(self, name: str) -> None:
- if self.find_ref(name) is None:
- self._define_ref(name, load=(VAR_LOAD_RESOLVE, name))
- def branch_update(self, branch_symbols: t.Sequence["Symbols"]) -> None:
- stores: t.Dict[str, int] = {}
- for branch in branch_symbols:
- for target in branch.stores:
- if target in self.stores:
- continue
- stores[target] = stores.get(target, 0) + 1
- for sym in branch_symbols:
- self.refs.update(sym.refs)
- self.loads.update(sym.loads)
- self.stores.update(sym.stores)
- for name, branch_count in stores.items():
- if branch_count == len(branch_symbols):
- continue
- target = self.find_ref(name) # type: ignore
- assert target is not None, "should not happen"
- if self.parent is not None:
- outer_target = self.parent.find_ref(name)
- if outer_target is not None:
- self.loads[target] = (VAR_LOAD_ALIAS, outer_target)
- continue
- self.loads[target] = (VAR_LOAD_RESOLVE, name)
- def dump_stores(self) -> t.Dict[str, str]:
- rv: t.Dict[str, str] = {}
- node: t.Optional["Symbols"] = self
- while node is not None:
- for name in sorted(node.stores):
- if name not in rv:
- rv[name] = self.find_ref(name) # type: ignore
- node = node.parent
- return rv
- def dump_param_targets(self) -> t.Set[str]:
- rv = set()
- node: t.Optional["Symbols"] = self
- while node is not None:
- for target, (instr, _) in self.loads.items():
- if instr == VAR_LOAD_PARAMETER:
- rv.add(target)
- node = node.parent
- return rv
- class RootVisitor(NodeVisitor):
- def __init__(self, symbols: "Symbols") -> None:
- self.sym_visitor = FrameSymbolVisitor(symbols)
- def _simple_visit(self, node: nodes.Node, **kwargs: t.Any) -> None:
- for child in node.iter_child_nodes():
- self.sym_visitor.visit(child)
- visit_Template = _simple_visit
- visit_Block = _simple_visit
- visit_Macro = _simple_visit
- visit_FilterBlock = _simple_visit
- visit_Scope = _simple_visit
- visit_If = _simple_visit
- visit_ScopedEvalContextModifier = _simple_visit
- def visit_AssignBlock(self, node: nodes.AssignBlock, **kwargs: t.Any) -> None:
- for child in node.body:
- self.sym_visitor.visit(child)
- def visit_CallBlock(self, node: nodes.CallBlock, **kwargs: t.Any) -> None:
- for child in node.iter_child_nodes(exclude=("call",)):
- self.sym_visitor.visit(child)
- def visit_OverlayScope(self, node: nodes.OverlayScope, **kwargs: t.Any) -> None:
- for child in node.body:
- self.sym_visitor.visit(child)
- def visit_For(
- self, node: nodes.For, for_branch: str = "body", **kwargs: t.Any
- ) -> None:
- if for_branch == "body":
- self.sym_visitor.visit(node.target, store_as_param=True)
- branch = node.body
- elif for_branch == "else":
- branch = node.else_
- elif for_branch == "test":
- self.sym_visitor.visit(node.target, store_as_param=True)
- if node.test is not None:
- self.sym_visitor.visit(node.test)
- return
- else:
- raise RuntimeError("Unknown for branch")
- if branch:
- for item in branch:
- self.sym_visitor.visit(item)
- def visit_With(self, node: nodes.With, **kwargs: t.Any) -> None:
- for target in node.targets:
- self.sym_visitor.visit(target)
- for child in node.body:
- self.sym_visitor.visit(child)
- def generic_visit(self, node: nodes.Node, *args: t.Any, **kwargs: t.Any) -> None:
- raise NotImplementedError(f"Cannot find symbols for {type(node).__name__!r}")
- class FrameSymbolVisitor(NodeVisitor):
- """A visitor for `Frame.inspect`."""
- def __init__(self, symbols: "Symbols") -> None:
- self.symbols = symbols
- def visit_Name(
- self, node: nodes.Name, store_as_param: bool = False, **kwargs: t.Any
- ) -> None:
- """All assignments to names go through this function."""
- if store_as_param or node.ctx == "param":
- self.symbols.declare_parameter(node.name)
- elif node.ctx == "store":
- self.symbols.store(node.name)
- elif node.ctx == "load":
- self.symbols.load(node.name)
- def visit_NSRef(self, node: nodes.NSRef, **kwargs: t.Any) -> None:
- self.symbols.load(node.name)
- def visit_If(self, node: nodes.If, **kwargs: t.Any) -> None:
- self.visit(node.test, **kwargs)
- original_symbols = self.symbols
- def inner_visit(nodes: t.Iterable[nodes.Node]) -> "Symbols":
- self.symbols = rv = original_symbols.copy()
- for subnode in nodes:
- self.visit(subnode, **kwargs)
- self.symbols = original_symbols
- return rv
- body_symbols = inner_visit(node.body)
- elif_symbols = inner_visit(node.elif_)
- else_symbols = inner_visit(node.else_ or ())
- self.symbols.branch_update([body_symbols, elif_symbols, else_symbols])
- def visit_Macro(self, node: nodes.Macro, **kwargs: t.Any) -> None:
- self.symbols.store(node.name)
- def visit_Import(self, node: nodes.Import, **kwargs: t.Any) -> None:
- self.generic_visit(node, **kwargs)
- self.symbols.store(node.target)
- def visit_FromImport(self, node: nodes.FromImport, **kwargs: t.Any) -> None:
- self.generic_visit(node, **kwargs)
- for name in node.names:
- if isinstance(name, tuple):
- self.symbols.store(name[1])
- else:
- self.symbols.store(name)
- def visit_Assign(self, node: nodes.Assign, **kwargs: t.Any) -> None:
- """Visit assignments in the correct order."""
- self.visit(node.node, **kwargs)
- self.visit(node.target, **kwargs)
- def visit_For(self, node: nodes.For, **kwargs: t.Any) -> None:
- """Visiting stops at for blocks. However the block sequence
- is visited as part of the outer scope.
- """
- self.visit(node.iter, **kwargs)
- def visit_CallBlock(self, node: nodes.CallBlock, **kwargs: t.Any) -> None:
- self.visit(node.call, **kwargs)
- def visit_FilterBlock(self, node: nodes.FilterBlock, **kwargs: t.Any) -> None:
- self.visit(node.filter, **kwargs)
- def visit_With(self, node: nodes.With, **kwargs: t.Any) -> None:
- for target in node.values:
- self.visit(target)
- def visit_AssignBlock(self, node: nodes.AssignBlock, **kwargs: t.Any) -> None:
- """Stop visiting at block assigns."""
- self.visit(node.target, **kwargs)
- def visit_Scope(self, node: nodes.Scope, **kwargs: t.Any) -> None:
- """Stop visiting at scopes."""
- def visit_Block(self, node: nodes.Block, **kwargs: t.Any) -> None:
- """Stop visiting at blocks."""
- def visit_OverlayScope(self, node: nodes.OverlayScope, **kwargs: t.Any) -> None:
- """Do not visit into overlay scopes."""
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