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-rw-r--r--libs2/yaml/resolver.py227
1 files changed, 227 insertions, 0 deletions
diff --git a/libs2/yaml/resolver.py b/libs2/yaml/resolver.py
new file mode 100644
index 000000000..528fbc0ea
--- /dev/null
+++ b/libs2/yaml/resolver.py
@@ -0,0 +1,227 @@
+
+__all__ = ['BaseResolver', 'Resolver']
+
+from error import *
+from nodes import *
+
+import re
+
+class ResolverError(YAMLError):
+ pass
+
+class BaseResolver(object):
+
+ DEFAULT_SCALAR_TAG = u'tag:yaml.org,2002:str'
+ DEFAULT_SEQUENCE_TAG = u'tag:yaml.org,2002:seq'
+ DEFAULT_MAPPING_TAG = u'tag:yaml.org,2002:map'
+
+ yaml_implicit_resolvers = {}
+ yaml_path_resolvers = {}
+
+ def __init__(self):
+ self.resolver_exact_paths = []
+ self.resolver_prefix_paths = []
+
+ 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))
+ add_implicit_resolver = classmethod(add_implicit_resolver)
+
+ 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, basestring) \
+ and node_check is not None:
+ raise ResolverError("Invalid node checker: %s" % node_check)
+ if not isinstance(index_check, (basestring, 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
+ add_path_resolver = classmethod(add_path_resolver)
+
+ 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, basestring):
+ 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, basestring):
+ 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 == u'':
+ resolvers = self.yaml_implicit_resolvers.get(u'', [])
+ else:
+ resolvers = self.yaml_implicit_resolvers.get(value[0], [])
+ resolvers += self.yaml_implicit_resolvers.get(None, [])
+ for tag, regexp in 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(
+ u'tag:yaml.org,2002:bool',
+ re.compile(ur'''^(?:yes|Yes|YES|no|No|NO
+ |true|True|TRUE|false|False|FALSE
+ |on|On|ON|off|Off|OFF)$''', re.X),
+ list(u'yYnNtTfFoO'))
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:float',
+ re.compile(ur'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
+ |\.[0-9_]+(?:[eE][-+][0-9]+)?
+ |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
+ |[-+]?\.(?:inf|Inf|INF)
+ |\.(?:nan|NaN|NAN))$''', re.X),
+ list(u'-+0123456789.'))
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:int',
+ re.compile(ur'''^(?:[-+]?0b[0-1_]+
+ |[-+]?0[0-7_]+
+ |[-+]?(?:0|[1-9][0-9_]*)
+ |[-+]?0x[0-9a-fA-F_]+
+ |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
+ list(u'-+0123456789'))
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:merge',
+ re.compile(ur'^(?:<<)$'),
+ [u'<'])
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:null',
+ re.compile(ur'''^(?: ~
+ |null|Null|NULL
+ | )$''', re.X),
+ [u'~', u'n', u'N', u''])
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:timestamp',
+ re.compile(ur'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
+ |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
+ (?:[Tt]|[ \t]+)[0-9][0-9]?
+ :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
+ (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
+ list(u'0123456789'))
+
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:value',
+ re.compile(ur'^(?:=)$'),
+ [u'='])
+
+# The following resolver is only for documentation purposes. It cannot work
+# because plain scalars cannot start with '!', '&', or '*'.
+Resolver.add_implicit_resolver(
+ u'tag:yaml.org,2002:yaml',
+ re.compile(ur'^(?:!|&|\*)$'),
+ list(u'!&*'))
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 14:16:20 +0000