| from .visitor import NodeVisitor | |
| VAR_LOAD_PARAMETER = "param" | |
| VAR_LOAD_RESOLVE = "resolve" | |
| VAR_LOAD_ALIAS = "alias" | |
| VAR_LOAD_UNDEFINED = "undefined" | |
| def find_symbols(nodes, parent_symbols=None): | |
| sym = Symbols(parent=parent_symbols) | |
| visitor = FrameSymbolVisitor(sym) | |
| for node in nodes: | |
| visitor.visit(node) | |
| return sym | |
| def symbols_for_node(node, parent_symbols=None): | |
| sym = Symbols(parent=parent_symbols) | |
| sym.analyze_node(node) | |
| return sym | |
| class Symbols: | |
| def __init__(self, parent=None, level=None): | |
| if level is None: | |
| if parent is None: | |
| level = 0 | |
| else: | |
| level = parent.level + 1 | |
| self.level = level | |
| self.parent = parent | |
| self.refs = {} | |
| self.loads = {} | |
| self.stores = set() | |
| def analyze_node(self, node, **kwargs): | |
| visitor = RootVisitor(self) | |
| visitor.visit(node, **kwargs) | |
| def _define_ref(self, name, load=None): | |
| 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): | |
| if target in self.loads: | |
| return self.loads[target] | |
| if self.parent is not None: | |
| return self.parent.find_load(target) | |
| def find_ref(self, name): | |
| if name in self.refs: | |
| return self.refs[name] | |
| if self.parent is not None: | |
| return self.parent.find_ref(name) | |
| def ref(self, name): | |
| 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): | |
| rv = 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): | |
| 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): | |
| self.stores.add(name) | |
| return self._define_ref(name, load=(VAR_LOAD_PARAMETER, None)) | |
| def load(self, name): | |
| target = self.find_ref(name) | |
| if target is None: | |
| self._define_ref(name, load=(VAR_LOAD_RESOLVE, name)) | |
| def branch_update(self, branch_symbols): | |
| stores = {} | |
| 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) | |
| 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): | |
| rv = {} | |
| node = self | |
| while node is not None: | |
| for name in node.stores: | |
| if name not in rv: | |
| rv[name] = self.find_ref(name) | |
| node = node.parent | |
| return rv | |
| def dump_param_targets(self): | |
| rv = set() | |
| node = 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): | |
| self.sym_visitor = FrameSymbolVisitor(symbols) | |
| def _simple_visit(self, node, **kwargs): | |
| for child in node.iter_child_nodes(): | |
| self.sym_visitor.visit(child) | |
| visit_Template = ( | |
| visit_Block | |
| ) = ( | |
| visit_Macro | |
| ) = ( | |
| visit_FilterBlock | |
| ) = visit_Scope = visit_If = visit_ScopedEvalContextModifier = _simple_visit | |
| def visit_AssignBlock(self, node, **kwargs): | |
| for child in node.body: | |
| self.sym_visitor.visit(child) | |
| def visit_CallBlock(self, node, **kwargs): | |
| for child in node.iter_child_nodes(exclude=("call",)): | |
| self.sym_visitor.visit(child) | |
| def visit_OverlayScope(self, node, **kwargs): | |
| for child in node.body: | |
| self.sym_visitor.visit(child) | |
| def visit_For(self, node, for_branch="body", **kwargs): | |
| 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") | |
| for item in branch or (): | |
| self.sym_visitor.visit(item) | |
| def visit_With(self, node, **kwargs): | |
| 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, *args, **kwargs): | |
| raise NotImplementedError( | |
| f"Cannot find symbols for {node.__class__.__name__!r}" | |
| ) | |
| class FrameSymbolVisitor(NodeVisitor): | |
| """A visitor for `Frame.inspect`.""" | |
| def __init__(self, symbols): | |
| self.symbols = symbols | |
| def visit_Name(self, node, store_as_param=False, **kwargs): | |
| """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, **kwargs): | |
| self.symbols.load(node.name) | |
| def visit_If(self, node, **kwargs): | |
| self.visit(node.test, **kwargs) | |
| original_symbols = self.symbols | |
| def inner_visit(nodes): | |
| 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, **kwargs): | |
| self.symbols.store(node.name) | |
| def visit_Import(self, node, **kwargs): | |
| self.generic_visit(node, **kwargs) | |
| self.symbols.store(node.target) | |
| def visit_FromImport(self, node, **kwargs): | |
| 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, **kwargs): | |
| """Visit assignments in the correct order.""" | |
| self.visit(node.node, **kwargs) | |
| self.visit(node.target, **kwargs) | |
| def visit_For(self, node, **kwargs): | |
| """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, **kwargs): | |
| self.visit(node.call, **kwargs) | |
| def visit_FilterBlock(self, node, **kwargs): | |
| self.visit(node.filter, **kwargs) | |
| def visit_With(self, node, **kwargs): | |
| for target in node.values: | |
| self.visit(target) | |
| def visit_AssignBlock(self, node, **kwargs): | |
| """Stop visiting at block assigns.""" | |
| self.visit(node.target, **kwargs) | |
| def visit_Scope(self, node, **kwargs): | |
| """Stop visiting at scopes.""" | |
| def visit_Block(self, node, **kwargs): | |
| """Stop visiting at blocks.""" | |
| def visit_OverlayScope(self, node, **kwargs): | |
| """Do not visit into overlay scopes.""" |