[EDIT] FILE: idtracking.py

from ._compat import iteritems 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(object): 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 = "l_%d_%s" % (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 unknown to the frame (%r)" % name ) 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 iteritems(stores): 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 iteritems(self.loads): 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( "Cannot find symbols for %r" % node.__class__.__name__ ) 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."""
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