| __all__ = ["BaseResolver", "Resolver"] |
| |
| from .error import * |
| from .nodes import * |
| |
| import re |
| |
| |
| class ResolverError(YAMLError): |
| pass |
| |
| |
| class BaseResolver: |
| |
| DEFAULT_SCALAR_TAG = "tag:yaml.org,2002:str" |
| DEFAULT_SEQUENCE_TAG = "tag:yaml.org,2002:seq" |
| DEFAULT_MAPPING_TAG = "tag:yaml.org,2002:map" |
| |
| yaml_implicit_resolvers = {} |
| yaml_path_resolvers = {} |
| |
| def __init__(self): |
| self.resolver_exact_paths = [] |
| self.resolver_prefix_paths = [] |
| |
| @classmethod |
| def add_implicit_resolver(cls, tag, regexp, first): |
| if not "yaml_implicit_resolvers" in cls.__dict__: |
| implicit_resolvers = {} |
| for key in cls.yaml_implicit_resolvers: |
| implicit_resolvers[key] = cls.yaml_implicit_resolvers[key][:] |
| cls.yaml_implicit_resolvers = implicit_resolvers |
| if first is None: |
| first = [None] |
| for ch in first: |
| cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp)) |
| |
| @classmethod |
| def add_path_resolver(cls, tag, path, kind=None): |
| # Note: `add_path_resolver` is experimental. The API could be changed. |
| # `new_path` is a pattern that is matched against the path from the |
| # root to the node that is being considered. `node_path` elements are |
| # tuples `(node_check, index_check)`. `node_check` is a node class: |
| # `ScalarNode`, `SequenceNode`, `MappingNode` or `None`. `None` |
| # matches any kind of a node. `index_check` could be `None`, a boolean |
| # value, a string value, or a number. `None` and `False` match against |
| # any _value_ of sequence and mapping nodes. `True` matches against |
| # any _key_ of a mapping node. A string `index_check` matches against |
| # a mapping value that corresponds to a scalar key which content is |
| # equal to the `index_check` value. An integer `index_check` matches |
| # against a sequence value with the index equal to `index_check`. |
| if not "yaml_path_resolvers" in cls.__dict__: |
| cls.yaml_path_resolvers = cls.yaml_path_resolvers.copy() |
| new_path = [] |
| for element in path: |
| if isinstance(element, (list, tuple)): |
| if len(element) == 2: |
| node_check, index_check = element |
| elif len(element) == 1: |
| node_check = element[0] |
| index_check = True |
| else: |
| raise ResolverError("Invalid path element: %s" % element) |
| else: |
| node_check = None |
| index_check = element |
| if node_check is str: |
| node_check = ScalarNode |
| elif node_check is list: |
| node_check = SequenceNode |
| elif node_check is dict: |
| node_check = MappingNode |
| elif ( |
| node_check not in [ScalarNode, SequenceNode, MappingNode] |
| and not isinstance(node_check, str) |
| and node_check is not None |
| ): |
| raise ResolverError("Invalid node checker: %s" % node_check) |
| if not isinstance(index_check, (str, int)) and index_check is not None: |
| raise ResolverError("Invalid index checker: %s" % index_check) |
| new_path.append((node_check, index_check)) |
| if kind is str: |
| kind = ScalarNode |
| elif kind is list: |
| kind = SequenceNode |
| elif kind is dict: |
| kind = MappingNode |
| elif kind not in [ScalarNode, SequenceNode, MappingNode] and kind is not None: |
| raise ResolverError("Invalid node kind: %s" % kind) |
| cls.yaml_path_resolvers[tuple(new_path), kind] = tag |
| |
| def descend_resolver(self, current_node, current_index): |
| if not self.yaml_path_resolvers: |
| return |
| exact_paths = {} |
| prefix_paths = [] |
| if current_node: |
| depth = len(self.resolver_prefix_paths) |
| for path, kind in self.resolver_prefix_paths[-1]: |
| if self.check_resolver_prefix( |
| depth, path, kind, current_node, current_index |
| ): |
| if len(path) > depth: |
| prefix_paths.append((path, kind)) |
| else: |
| exact_paths[kind] = self.yaml_path_resolvers[path, kind] |
| else: |
| for path, kind in self.yaml_path_resolvers: |
| if not path: |
| exact_paths[kind] = self.yaml_path_resolvers[path, kind] |
| else: |
| prefix_paths.append((path, kind)) |
| self.resolver_exact_paths.append(exact_paths) |
| self.resolver_prefix_paths.append(prefix_paths) |
| |
| def ascend_resolver(self): |
| if not self.yaml_path_resolvers: |
| return |
| self.resolver_exact_paths.pop() |
| self.resolver_prefix_paths.pop() |
| |
| def check_resolver_prefix(self, depth, path, kind, current_node, current_index): |
| node_check, index_check = path[depth - 1] |
| if isinstance(node_check, str): |
| if current_node.tag != node_check: |
| return |
| elif node_check is not None: |
| if not isinstance(current_node, node_check): |
| return |
| if index_check is True and current_index is not None: |
| return |
| if (index_check is False or index_check is None) and current_index is None: |
| return |
| if isinstance(index_check, str): |
| if not ( |
| isinstance(current_index, ScalarNode) |
| and index_check == current_index.value |
| ): |
| return |
| elif isinstance(index_check, int) and not isinstance(index_check, bool): |
| if index_check != current_index: |
| return |
| return True |
| |
| def resolve(self, kind, value, implicit): |
| if kind is ScalarNode and implicit[0]: |
| if value == "": |
| resolvers = self.yaml_implicit_resolvers.get("", []) |
| else: |
| resolvers = self.yaml_implicit_resolvers.get(value[0], []) |
| wildcard_resolvers = self.yaml_implicit_resolvers.get(None, []) |
| for tag, regexp in resolvers + wildcard_resolvers: |
| if regexp.match(value): |
| return tag |
| implicit = implicit[1] |
| if self.yaml_path_resolvers: |
| exact_paths = self.resolver_exact_paths[-1] |
| if kind in exact_paths: |
| return exact_paths[kind] |
| if None in exact_paths: |
| return exact_paths[None] |
| if kind is ScalarNode: |
| return self.DEFAULT_SCALAR_TAG |
| elif kind is SequenceNode: |
| return self.DEFAULT_SEQUENCE_TAG |
| elif kind is MappingNode: |
| return self.DEFAULT_MAPPING_TAG |
| |
| |
| class Resolver(BaseResolver): |
| pass |
| |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:bool", |
| re.compile( |
| r"""^(?:yes|Yes|YES|no|No|NO |
| |true|True|TRUE|false|False|FALSE |
| |on|On|ON|off|Off|OFF)$""", |
| re.X, |
| ), |
| list("yYnNtTfFoO"), |
| ) |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:float", |
| re.compile( |
| r"""^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)? |
| |\.[0-9][0-9_]*(?:[eE][-+][0-9]+)? |
| |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]* |
| |[-+]?\.(?:inf|Inf|INF) |
| |\.(?:nan|NaN|NAN))$""", |
| re.X, |
| ), |
| list("-+0123456789."), |
| ) |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:int", |
| re.compile( |
| r"""^(?:[-+]?0b[0-1_]+ |
| |[-+]?0[0-7_]+ |
| |[-+]?(?:0|[1-9][0-9_]*) |
| |[-+]?0x[0-9a-fA-F_]+ |
| |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$""", |
| re.X, |
| ), |
| list("-+0123456789"), |
| ) |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:merge", re.compile(r"^(?:<<)$"), ["<"] |
| ) |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:null", |
| re.compile( |
| r"""^(?: ~ |
| |null|Null|NULL |
| | )$""", |
| re.X, |
| ), |
| ["~", "n", "N", ""], |
| ) |
| |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:timestamp", |
| re.compile( |
| r"""^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] |
| |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]? |
| (?:[Tt]|[ \t]+)[0-9][0-9]? |
| :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)? |
| (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$""", |
| re.X, |
| ), |
| list("0123456789"), |
| ) |
| |
| Resolver.add_implicit_resolver("tag:yaml.org,2002:value", re.compile(r"^(?:=)$"), ["="]) |
| |
| # The following resolver is only for documentation purposes. It cannot work |
| # because plain scalars cannot start with '!', '&', or '*'. |
| Resolver.add_implicit_resolver( |
| "tag:yaml.org,2002:yaml", re.compile(r"^(?:!|&|\*)$"), list("!&*") |
| ) |
