diff options
Diffstat (limited to 'buildstream/_yaml.py')
| -rw-r--r-- | buildstream/_yaml.py | 1570 |
1 files changed, 967 insertions, 603 deletions
diff --git a/buildstream/_yaml.py b/buildstream/_yaml.py index 4c2ae2b4d..1512a3cb8 100644 --- a/buildstream/_yaml.py +++ b/buildstream/_yaml.py @@ -1,5 +1,6 @@ # # Copyright (C) 2018 Codethink Limited +# Copyright (C) 2019 Bloomberg LLP # # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public @@ -16,147 +17,111 @@ # # Authors: # Tristan Van Berkom <tristan.vanberkom@codethink.co.uk> +# Daniel Silverstone <daniel.silverstone@codethink.co.uk> +# James Ennis <james.ennis@codethink.co.uk> import sys -import collections import string -from copy import deepcopy from contextlib import ExitStack +from collections import OrderedDict, namedtuple +from collections.abc import Mapping, Sequence +from copy import deepcopy +from itertools import count from ruamel import yaml -from ruamel.yaml.representer import SafeRepresenter, RoundTripRepresenter -from ruamel.yaml.constructor import RoundTripConstructor from ._exceptions import LoadError, LoadErrorReason -# This overrides the ruamel constructor to treat everything as a string -RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:int', RoundTripConstructor.construct_yaml_str) -RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:float', RoundTripConstructor.construct_yaml_str) - -# We store information in the loaded yaml on a DictProvenance -# stored in all dictionaries under this key -PROVENANCE_KEY = '__bst_provenance_info' - -# Provides information about file for provenance +# Without this, pylint complains about all the `type(foo) is blah` checks +# because it feels isinstance() is more idiomatic. Sadly, it is much slower to +# do `isinstance(foo, blah)` for reasons I am unable to fathom. As such, we +# blanket disable the check for this module. # -# Args: -# name (str): Full path to the file -# shortname (str): Relative path to the file -# project (Project): Project where the shortname is relative from -class ProvenanceFile(): - def __init__(self, name, shortname, project): - self.name = name - self.shortname = shortname - self.project = project +# pylint: disable=unidiomatic-typecheck -# Provenance tracks the origin of a given node in the parsed dictionary. +# Node() # -# Args: -# node (dict, list, value): A binding to the originally parsed value -# filename (str): The filename the node was loaded from -# toplevel (dict): The toplevel of the loaded file, suitable for later dumps -# line (int): The line number where node was parsed -# col (int): The column number where node was parsed -# -class Provenance(): - def __init__(self, filename, node, toplevel, line=0, col=0): - self.filename = filename - self.node = node - self.toplevel = toplevel - self.line = line - self.col = col - - # Convert a Provenance to a string for error reporting - def __str__(self): - filename = self.filename.shortname - if self.filename.project and self.filename.project.junction: - filename = "{}:{}".format(self.filename.project.junction.name, self.filename.shortname) - - return "{} [line {:d} column {:d}]".format(filename, self.line, self.col) - - # Abstract method - def clone(self): - pass # pragma: nocover - - -# A Provenance for dictionaries, these are stored in the copy of the -# loaded YAML tree and track the provenance of all members +# Container for YAML loaded data and its provenance # -class DictProvenance(Provenance): - def __init__(self, filename, node, toplevel, line=None, col=None): - - if line is None or col is None: - # Special case for loading an empty dict - if hasattr(node, 'lc'): - line = node.lc.line + 1 - col = node.lc.col - else: - line = 1 - col = 0 - - super(DictProvenance, self).__init__(filename, node, toplevel, line=line, col=col) - - self.members = {} - - def clone(self): - provenance = DictProvenance(self.filename, self.node, self.toplevel, - line=self.line, col=self.col) - - provenance.members = { - member_name: member.clone() - for member_name, member in self.members.items() - } - return provenance - - -# A Provenance for dict members +# All nodes returned (and all internal lists/strings) have this type (rather +# than a plain tuple, to distinguish them in things like node_sanitize) # -class MemberProvenance(Provenance): - def __init__(self, filename, parent_dict, member_name, toplevel, - node=None, line=None, col=None): - - if parent_dict is not None: - node = parent_dict[member_name] - line, col = parent_dict.lc.value(member_name) - line += 1 - - super(MemberProvenance, self).__init__( - filename, node, toplevel, line=line, col=col) +# Members: +# value (str/list/dict): The loaded value. +# file_index (int): Index within _FILE_LIST (a list of loaded file paths). +# Negative indices indicate synthetic nodes so that +# they can be referenced. +# line (int): The line number within the file where the value appears. +# col (int): The column number within the file where the value appears. +# +# For efficiency, each field should be accessed by its integer index: +# value = Node[0] +# file_index = Node[1] +# line = Node[2] +# column = Node[3] +# +class Node(namedtuple('Node', ['value', 'file_index', 'line', 'column'])): + def __contains__(self, what): + assert False, \ + "BUG: Attempt to do `{} in {}` test".format(what, self) - # Only used if member is a list - self.elements = [] - def clone(self): - provenance = MemberProvenance(self.filename, None, None, self.toplevel, - node=self.node, line=self.line, col=self.col) - provenance.elements = [e.clone() for e in self.elements] - return provenance +# File name handling +_FILE_LIST = [] -# A Provenance for list elements -# -class ElementProvenance(Provenance): - def __init__(self, filename, parent_list, index, toplevel, - node=None, line=None, col=None): +# Purely synthetic node will have None for the file number, have line number +# zero, and a negative column number which comes from inverting the next value +# out of this counter. Synthetic nodes created with a reference node will +# have a file number from the reference node, some unknown line number, and +# a negative column number from this counter. +_SYNTHETIC_COUNTER = count(start=-1, step=-1) - if parent_list is not None: - node = parent_list[index] - line, col = parent_list.lc.item(index) - line += 1 - super(ElementProvenance, self).__init__( - filename, node, toplevel, line=line, col=col) +# Returned from node_get_provenance +class ProvenanceInformation: - # Only used if element is a list - self.elements = [] + __slots__ = ( + "filename", + "shortname", + "displayname", + "line", + "col", + "toplevel", + "node", + "project", + "is_synthetic", + ) - def clone(self): - provenance = ElementProvenance(self.filename, None, None, self.toplevel, - node=self.node, line=self.line, col=self.col) + def __init__(self, nodeish): + self.node = nodeish + if (nodeish is None) or (nodeish[1] is None): + self.filename = "" + self.shortname = "" + self.displayname = "" + self.line = 1 + self.col = 0 + self.toplevel = None + self.project = None + else: + fileinfo = _FILE_LIST[nodeish[1]] + self.filename = fileinfo[0] + self.shortname = fileinfo[1] + self.displayname = fileinfo[2] + # We add 1 here to convert from computerish to humanish + self.line = nodeish[2] + 1 + self.col = nodeish[3] + self.toplevel = fileinfo[3] + self.project = fileinfo[4] + self.is_synthetic = (self.filename == '') or (self.col < 0) - provenance.elements = [e.clone for e in self.elements] - return provenance + # Convert a Provenance to a string for error reporting + def __str__(self): + if self.is_synthetic: + return "{} [synthetic node]".format(self.displayname) + else: + return "{} [line {:d} column {:d}]".format(self.displayname, self.line, self.col) # These exceptions are intended to be caught entirely within @@ -166,17 +131,165 @@ class CompositeError(Exception): def __init__(self, path, message): super(CompositeError, self).__init__(message) self.path = path + self.message = message + + +class YAMLLoadError(Exception): + pass + + +# Representer for YAML events comprising input to the BuildStream format. +# +# All streams MUST represent a single document which must be a Mapping. +# Anything else is considered an error. +# +# Mappings must only have string keys, values are always represented as +# strings if they are scalar, or else as simple dictionaries and lists. +# +class Representer: + __slots__ = ( + "_file_index", + "state", + "output", + "keys", + ) + + # Initialise a new representer + # + # The file index is used to store into the Node instances so that the + # provenance of the YAML can be tracked. + # + # Args: + # file_index (int): The index of this YAML file + def __init__(self, file_index): + self._file_index = file_index + self.state = "init" + self.output = [] + self.keys = [] + + # Handle a YAML parse event + # + # Args: + # event (YAML Event): The event to be handled + # + # Raises: + # YAMLLoadError: Something went wrong. + def handle_event(self, event): + if getattr(event, "anchor", None) is not None: + raise YAMLLoadError("Anchors are disallowed in BuildStream at line {} column {}" + .format(event.start_mark.line, event.start_mark.column)) + + if event.__class__.__name__ == "ScalarEvent": + if event.tag is not None: + if not event.tag.startswith("tag:yaml.org,2002:"): + raise YAMLLoadError( + "Non-core tag expressed in input. " + + "This is disallowed in BuildStream. At line {} column {}" + .format(event.start_mark.line, event.start_mark.column)) + + handler = "_handle_{}_{}".format(self.state, event.__class__.__name__) + handler = getattr(self, handler, None) + if handler is None: + raise YAMLLoadError( + "Invalid input detected. No handler for {} in state {} at line {} column {}" + .format(event, self.state, event.start_mark.line, event.start_mark.column)) + + if handler is None: + raise YAMLLoadError( + "Invalid input detected. No handler for {} in state {} at line {} column {}" + .format(event, self.state, event.start_mark.line, event.start_mark.column)) + + self.state = handler(event) # pylint: disable=not-callable + + # Get the output of the YAML parse + # + # Returns: + # (Node or None): Return the Node instance of the top level mapping or + # None if there wasn't one. + def get_output(self): + try: + return self.output[0] + except IndexError: + return None + + def _handle_init_StreamStartEvent(self, ev): + return "stream" + + def _handle_stream_DocumentStartEvent(self, ev): + return "doc" + + def _handle_doc_MappingStartEvent(self, ev): + newmap = Node({}, self._file_index, ev.start_mark.line, ev.start_mark.column) + self.output.append(newmap) + return "wait_key" + + def _handle_wait_key_ScalarEvent(self, ev): + self.keys.append(ev.value) + return "wait_value" + + def _handle_wait_value_ScalarEvent(self, ev): + key = self.keys.pop() + self.output[-1][0][key] = \ + Node(ev.value, self._file_index, ev.start_mark.line, ev.start_mark.column) + return "wait_key" + + def _handle_wait_value_MappingStartEvent(self, ev): + new_state = self._handle_doc_MappingStartEvent(ev) + key = self.keys.pop() + self.output[-2][0][key] = self.output[-1] + return new_state + + def _handle_wait_key_MappingEndEvent(self, ev): + # We've finished a mapping, so pop it off the output stack + # unless it's the last one in which case we leave it + if len(self.output) > 1: + self.output.pop() + if type(self.output[-1][0]) is list: + return "wait_list_item" + else: + return "wait_key" + else: + return "doc" + + def _handle_wait_value_SequenceStartEvent(self, ev): + self.output.append(Node([], self._file_index, ev.start_mark.line, ev.start_mark.column)) + self.output[-2][0][self.keys[-1]] = self.output[-1] + return "wait_list_item" + + def _handle_wait_list_item_SequenceStartEvent(self, ev): + self.keys.append(len(self.output[-1][0])) + self.output.append(Node([], self._file_index, ev.start_mark.line, ev.start_mark.column)) + self.output[-2][0].append(self.output[-1]) + return "wait_list_item" + + def _handle_wait_list_item_SequenceEndEvent(self, ev): + # When ending a sequence, we need to pop a key because we retain the + # key until the end so that if we need to mutate the underlying entry + # we can. + key = self.keys.pop() + self.output.pop() + if type(key) is int: + return "wait_list_item" + else: + return "wait_key" + + def _handle_wait_list_item_ScalarEvent(self, ev): + self.output[-1][0].append( + Node(ev.value, self._file_index, ev.start_mark.line, ev.start_mark.column)) + return "wait_list_item" + + def _handle_wait_list_item_MappingStartEvent(self, ev): + new_state = self._handle_doc_MappingStartEvent(ev) + self.output[-2][0].append(self.output[-1]) + return new_state + def _handle_doc_DocumentEndEvent(self, ev): + if len(self.output) != 1: + raise YAMLLoadError("Zero, or more than one document found in YAML stream") + return "stream" -class CompositeTypeError(CompositeError): - def __init__(self, path, expected_type, actual_type): - super(CompositeTypeError, self).__init__( - path, - "Error compositing dictionary key '{}', expected source type '{}' " - "but received type '{}'" - .format(path, expected_type.__name__, actual_type.__name__)) - self.expected_type = expected_type - self.actual_type = actual_type + def _handle_stream_StreamEndEvent(self, ev): + return "init" # Loads a dictionary from some YAML @@ -186,6 +299,7 @@ class CompositeTypeError(CompositeError): # shortname (str): The filename in shorthand for error reporting (or None) # copy_tree (bool): Whether to make a copy, preserving the original toplevels # for later serialization +# project (Project): The (optional) project to associate the parsed YAML with # # Returns (dict): A loaded copy of the YAML file with provenance information # @@ -195,14 +309,22 @@ def load(filename, shortname=None, copy_tree=False, *, project=None): if not shortname: shortname = filename - file = ProvenanceFile(filename, shortname, project) + if (project is not None) and (project.junction is not None): + displayname = "{}:{}".format(project.junction.name, shortname) + else: + displayname = shortname + + file_number = len(_FILE_LIST) + _FILE_LIST.append((filename, shortname, displayname, None, project)) try: - data = None with open(filename) as f: contents = f.read() - data = load_data(contents, file, copy_tree=copy_tree) + data = load_data(contents, + file_index=file_number, + file_name=filename, + copy_tree=copy_tree) return data except FileNotFoundError as e: @@ -216,97 +338,57 @@ def load(filename, shortname=None, copy_tree=False, *, project=None): # Like load(), but doesnt require the data to be in a file # -def load_data(data, file=None, copy_tree=False): +def load_data(data, file_index=None, file_name=None, copy_tree=False): try: - contents = yaml.load(data, yaml.loader.RoundTripLoader, preserve_quotes=True) - except (yaml.scanner.ScannerError, yaml.composer.ComposerError, yaml.parser.ParserError) as e: + rep = Representer(file_index) + for event in yaml.parse(data, Loader=yaml.CBaseLoader): + rep.handle_event(event) + contents = rep.get_output() + except YAMLLoadError as e: raise LoadError(LoadErrorReason.INVALID_YAML, - "Malformed YAML:\n\n{}\n\n{}\n".format(e.problem, e.problem_mark)) from e + "Malformed YAML:\n\n{}\n\n".format(e)) from e + except Exception as e: + raise LoadError(LoadErrorReason.INVALID_YAML, + "Severely malformed YAML:\n\n{}\n\n".format(e)) from e - if not isinstance(contents, dict): + if not isinstance(contents, tuple) or not isinstance(contents[0], dict): # Special case allowance for None, when the loaded file has only comments in it. if contents is None: - contents = {} + contents = Node({}, file_index, 0, 0) else: raise LoadError(LoadErrorReason.INVALID_YAML, "YAML file has content of type '{}' instead of expected type 'dict': {}" - .format(type(contents).__name__, file.name)) + .format(type(contents[0]).__name__, file_name)) + + # Store this away because we'll use it later for "top level" provenance + if file_index is not None: + _FILE_LIST[file_index] = ( + _FILE_LIST[file_index][0], # Filename + _FILE_LIST[file_index][1], # Shortname + _FILE_LIST[file_index][2], # Displayname + contents, + _FILE_LIST[file_index][4], # Project + ) - return node_decorated_copy(file, contents, copy_tree=copy_tree) + if copy_tree: + contents = node_copy(contents) + return contents -# Dumps a previously loaded YAML node to a file +# dump() # -# Args: -# node (dict): A node previously loaded with _yaml.load() above -# filename (str): The YAML file to load +# Write a YAML node structure out to disk. # -def dump(node, filename=None): - with ExitStack() as stack: - if filename: - from . import utils - f = stack.enter_context(utils.save_file_atomic(filename, 'w')) - else: - f = sys.stdout - yaml.round_trip_dump(node, f) - - -# node_decorated_copy() -# -# Create a copy of a loaded dict tree decorated with Provenance -# information, used directly after loading yaml +# This will always call `node_sanitize` on its input, so if you wanted +# to output something close to what you read in, consider using the +# `roundtrip_load` and `roundtrip_dump` function pair instead. # # Args: -# filename (str): The filename -# toplevel (node): The toplevel dictionary node -# copy_tree (bool): Whether to load a copy and preserve the original -# -# Returns: A copy of the toplevel decorated with Provinance -# -def node_decorated_copy(filename, toplevel, copy_tree=False): - if copy_tree: - result = deepcopy(toplevel) - else: - result = toplevel - - node_decorate_dict(filename, result, toplevel, toplevel) - - return result - - -def node_decorate_dict(filename, target, source, toplevel): - provenance = DictProvenance(filename, source, toplevel) - target[PROVENANCE_KEY] = provenance - - for key, value in node_items(source): - member = MemberProvenance(filename, source, key, toplevel) - provenance.members[key] = member - - target_value = target.get(key) - if isinstance(value, collections.abc.Mapping): - node_decorate_dict(filename, target_value, value, toplevel) - elif isinstance(value, list): - member.elements = node_decorate_list(filename, target_value, value, toplevel) - - -def node_decorate_list(filename, target, source, toplevel): - - elements = [] - - for item in source: - idx = source.index(item) - target_item = target[idx] - element = ElementProvenance(filename, source, idx, toplevel) - - if isinstance(item, collections.abc.Mapping): - node_decorate_dict(filename, target_item, item, toplevel) - elif isinstance(item, list): - element.elements = node_decorate_list(filename, target_item, item, toplevel) - - elements.append(element) - - return elements +# contents (any): Content to write out +# filename (str): The (optional) file name to write out to +def dump(contents, filename=None): + roundtrip_dump(node_sanitize(contents), file=filename) # node_get_provenance() @@ -321,15 +403,20 @@ def node_decorate_list(filename, target, source, toplevel): # Returns: The Provenance of the dict, member or list element # def node_get_provenance(node, key=None, indices=None): + assert is_node(node) + + if key is None: + # Retrieving the provenance for this node directly + return ProvenanceInformation(node) - provenance = node.get(PROVENANCE_KEY) - if provenance and key: - provenance = provenance.members.get(key) - if provenance and indices is not None: - for index in indices: - provenance = provenance.elements[index] + if key and not indices: + return ProvenanceInformation(node[0].get(key)) - return provenance + nodeish = node[0].get(key) + for idx in indices: + nodeish = nodeish[0][idx] + + return ProvenanceInformation(nodeish) # A sentinel to be used as a default argument for functions that need @@ -361,41 +448,51 @@ _sentinel = object() # Returned strings are stripped of leading and trailing whitespace # def node_get(node, expected_type, key, indices=None, *, default_value=_sentinel, allow_none=False): - value = node.get(key, default_value) - if value is _sentinel: - provenance = node_get_provenance(node) - raise LoadError(LoadErrorReason.INVALID_DATA, - "{}: Dictionary did not contain expected key '{}'".format(provenance, key)) + assert type(node) is Node path = key - if indices is not None: + if indices is None: + if default_value is _sentinel: + value = node[0].get(key, Node(default_value, None, 0, 0)) + else: + value = node[0].get(key, Node(default_value, None, 0, next(_SYNTHETIC_COUNTER))) + + if value[0] is _sentinel: + provenance = node_get_provenance(node) + raise LoadError(LoadErrorReason.INVALID_DATA, + "{}: Dictionary did not contain expected key '{}'".format(provenance, key)) + else: # Implied type check of the element itself - value = node_get(node, list, key) + # No need to synthesise useful node content as we destructure it immediately + value = Node(node_get(node, list, key), None, 0, 0) for index in indices: - value = value[index] + value = value[0][index] + if type(value) is not Node: + value = (value,) path += '[{:d}]'.format(index) # Optionally allow None as a valid value for any type - if value is None and (allow_none or default_value is None): + if value[0] is None and (allow_none or default_value is None): return None - if not isinstance(value, expected_type): + if (expected_type is not None) and (not isinstance(value[0], expected_type)): # Attempt basic conversions if possible, typically we want to # be able to specify numeric values and convert them to strings, # but we dont want to try converting dicts/lists try: - if (expected_type == bool and isinstance(value, str)): + if (expected_type == bool and isinstance(value[0], str)): # Dont coerce booleans to string, this makes "False" strings evaluate to True - if value in ('True', 'true'): - value = True - elif value in ('False', 'false'): - value = False + # We don't structure into full nodes since there's no need. + if value[0] in ('True', 'true'): + value = (True, None, 0, 0) + elif value[0] in ('False', 'false'): + value = (False, None, 0, 0) else: raise ValueError() elif not (expected_type == list or expected_type == dict or - isinstance(value, (list, dict))): - value = expected_type(value) + isinstance(value[0], (list, dict))): + value = (expected_type(value[0]), None, 0, 0) else: raise ValueError() except (ValueError, TypeError): @@ -404,13 +501,115 @@ def node_get(node, expected_type, key, indices=None, *, default_value=_sentinel, "{}: Value of '{}' is not of the expected type '{}'" .format(provenance, path, expected_type.__name__)) + # Now collapse lists, and scalars, to their value, leaving nodes as-is + if type(value[0]) is not dict: + value = value[0] + # Trim it at the bud, let all loaded strings from yaml be stripped of whitespace - if isinstance(value, str): + if type(value) is str: value = value.strip() + elif type(value) is list: + # Now we create a fresh list which unwraps the str and list types + # semi-recursively. + value = __trim_list_provenance(value) + return value +def __trim_list_provenance(value): + ret = [] + for entry in value: + if type(entry) is not Node: + entry = (entry, None, 0, 0) + if type(entry[0]) is list: + ret.append(__trim_list_provenance(entry[0])) + elif type(entry[0]) is dict: + ret.append(entry) + else: + ret.append(entry[0]) + return ret + + +# node_set() +# +# Set an item within the node. If using `indices` be aware that the entry must +# already exist, or else a KeyError will be raised. Use `node_extend_list` to +# create entries before using `node_set` +# +# Args: +# node (tuple): The node +# key (str): The key name +# value: The value +# indices: Any indices to index into the list referenced by key, like in +# `node_get` (must be a list of integers) +# +def node_set(node, key, value, indices=None): + if indices: + node = node[0][key] + key = indices.pop() + for idx in indices: + node = node[0][idx] + if type(value) is Node: + node[0][key] = value + else: + try: + # Need to do this just in case we're modifying a list + old_value = node[0][key] + except KeyError: + old_value = None + if old_value is None: + node[0][key] = Node(value, node[1], node[2], next(_SYNTHETIC_COUNTER)) + else: + node[0][key] = Node(value, old_value[1], old_value[2], old_value[3]) + + +# node_extend_list() +# +# Extend a list inside a node to a given length, using the passed +# default value to fill it out. +# +# Valid default values are: +# Any string +# An empty dict +# An empty list +# +# Args: +# node (node): The node +# key (str): The list name in the node +# length (int): The length to extend the list to +# default (any): The default value to extend with. +def node_extend_list(node, key, length, default): + assert type(default) is str or default in ([], {}) + + list_node = node[0].get(key) + if list_node is None: + list_node = node[0][key] = Node([], node[1], node[2], next(_SYNTHETIC_COUNTER)) + + assert type(list_node[0]) is list + + the_list = list_node[0] + def_type = type(default) + + file_index = node[1] + if the_list: + line_num = the_list[-1][2] + else: + line_num = list_node[2] + + while length > len(the_list): + if def_type is str: + value = default + elif def_type is list: + value = [] + else: + value = {} + + line_num += 1 + + the_list.append(Node(value, file_index, line_num, next(_SYNTHETIC_COUNTER))) + + # node_items() # # A convenience generator for iterating over loaded key/value @@ -424,44 +623,147 @@ def node_get(node, expected_type, key, indices=None, *, default_value=_sentinel, # (anything): The value for the key # def node_items(node): - for key, value in node.items(): - if key == PROVENANCE_KEY: - continue - yield (key, value) + if type(node) is not Node: + node = Node(node, None, 0, 0) + for key, value in node[0].items(): + if type(value) is not Node: + value = Node(value, None, 0, 0) + if type(value[0]) is dict: + yield (key, value) + elif type(value[0]) is list: + yield (key, __trim_list_provenance(value[0])) + else: + yield (key, value[0]) + + +# node_del() +# +# A convenience generator for iterating over loaded key/value +# tuples in a dictionary loaded from project YAML. +# +# Args: +# node (dict): The dictionary node +# key (str): The key we want to remove +# safe (bool): Whether to raise a KeyError if unable +# +def node_del(node, key, safe=False): + try: + del node[0][key] + except KeyError: + if not safe: + raise + +# is_node() +# +# A test method which returns whether or not the passed in value +# is a valid YAML node. It is not valid to call this on a Node +# object which is not a Mapping. +# +# Args: +# maybenode (any): The object to test for nodeness +# +# Returns: +# (bool): Whether or not maybenode was a Node +# +def is_node(maybenode): + # It's a programming error to give this a Node which isn't a mapping + # so assert that. + assert (type(maybenode) is not Node) or (type(maybenode[0]) is dict) + # Now return the type check + return type(maybenode) is Node -# Gives a node a dummy provenance, in case of compositing dictionaries -# where the target is an empty {} -def ensure_provenance(node): - provenance = node.get(PROVENANCE_KEY) - if not provenance: - provenance = DictProvenance(ProvenanceFile('', '', None), node, node) - node[PROVENANCE_KEY] = provenance - return provenance +# new_synthetic_file() +# +# Create a new synthetic mapping node, with an associated file entry +# (in _FILE_LIST) such that later tracking can correctly determine which +# file needs writing to in order to persist the changes. +# +# Args: +# filename (str): The name of the synthetic file to create +# project (Project): The optional project to associate this synthetic file with +# +# Returns: +# (Node): An empty YAML mapping node, whose provenance is to this new +# synthetic file +# +def new_synthetic_file(filename, project=None): + file_index = len(_FILE_LIST) + node = Node({}, file_index, 0, 0) + _FILE_LIST.append((filename, + filename, + "<synthetic {}>".format(filename), + node, + project)) + return node -# is_ruamel_str(): +# new_empty_node() # # Args: -# value: A value loaded from ruamel +# ref_node (Node): Optional node whose provenance should be referenced # -# This returns if the value is "stringish", since ruamel -# has some complex types to represent strings, this is needed -# to avoid compositing exceptions in order to allow various -# string types to be interchangable and acceptable +# Returns +# (Node): A new empty YAML mapping node # -def is_ruamel_str(value): +def new_empty_node(ref_node=None): + if ref_node is not None: + return Node({}, ref_node[1], ref_node[2], next(_SYNTHETIC_COUNTER)) + else: + return Node({}, None, 0, 0) - if isinstance(value, str): - return True - elif isinstance(value, yaml.scalarstring.ScalarString): - return True - return False +# new_node_from_dict() +# +# Args: +# indict (dict): The input dictionary +# +# Returns: +# (Node): A new synthetic YAML tree which represents this dictionary +# +def new_node_from_dict(indict): + ret = {} + for k, v in indict.items(): + vtype = type(v) + if vtype is dict: + ret[k] = new_node_from_dict(v) + elif vtype is list: + ret[k] = __new_node_from_list(v) + else: + ret[k] = Node(str(v), None, 0, next(_SYNTHETIC_COUNTER)) + return Node(ret, None, 0, next(_SYNTHETIC_COUNTER)) + + +# Internal function to help new_node_from_dict() to handle lists +def __new_node_from_list(inlist): + ret = [] + for v in inlist: + vtype = type(v) + if vtype is dict: + ret.append(new_node_from_dict(v)) + elif vtype is list: + ret.append(__new_node_from_list(v)) + else: + ret.append(Node(str(v), None, 0, next(_SYNTHETIC_COUNTER))) + return Node(ret, None, 0, next(_SYNTHETIC_COUNTER)) + + +# node_contains() +# +# Args: +# node (Node): The mapping node to query the contents of +# entry (str): The key to look for in the mapping node +# +# Returns: +# (bool): Whether entry is in the mapping in node. +# +def node_contains(node, entry): + assert type(node) is Node + return entry in node[0] -# is_composite_list +# _is_composite_list # # Checks if the given node is a Mapping with array composition # directives. @@ -477,9 +779,9 @@ def is_ruamel_str(value): # (LoadError): If node was a mapping and contained a mix of # list composition directives and other keys # -def is_composite_list(node): +def _is_composite_list(node): - if isinstance(node, collections.abc.Mapping): + if type(node[0]) is dict: has_directives = False has_keys = False @@ -499,309 +801,156 @@ def is_composite_list(node): return False -# composite_list_prepend -# -# Internal helper for list composition -# -# Args: -# target_node (dict): A simple dictionary -# target_key (dict): The key indicating a literal array to prepend to -# source_node (dict): Another simple dictionary -# source_key (str): The key indicating an array to prepend to the target -# -# Returns: -# (bool): True if a source list was found and compositing occurred -# -def composite_list_prepend(target_node, target_key, source_node, source_key): - - source_list = node_get(source_node, list, source_key, default_value=[]) - if not source_list: - return False - - target_provenance = node_get_provenance(target_node) - source_provenance = node_get_provenance(source_node) - - if target_node.get(target_key) is None: - target_node[target_key] = [] - - source_list = list_copy(source_list) - target_list = target_node[target_key] - - for element in reversed(source_list): - target_list.insert(0, element) - - if not target_provenance.members.get(target_key): - target_provenance.members[target_key] = source_provenance.members[source_key].clone() - else: - for p in reversed(source_provenance.members[source_key].elements): - target_provenance.members[target_key].elements.insert(0, p.clone()) - - return True - - -# composite_list_append +# _compose_composite_list() # -# Internal helper for list composition +# Composes a composite list (i.e. a dict with list composition directives) +# on top of a target list which is a composite list itself. # # Args: -# target_node (dict): A simple dictionary -# target_key (dict): The key indicating a literal array to append to -# source_node (dict): Another simple dictionary -# source_key (str): The key indicating an array to append to the target -# -# Returns: -# (bool): True if a source list was found and compositing occurred -# -def composite_list_append(target_node, target_key, source_node, source_key): - - source_list = node_get(source_node, list, source_key, default_value=[]) - if not source_list: - return False - - target_provenance = node_get_provenance(target_node) - source_provenance = node_get_provenance(source_node) - - if target_node.get(target_key) is None: - target_node[target_key] = [] - - source_list = list_copy(source_list) - target_list = target_node[target_key] - - target_list.extend(source_list) - - if not target_provenance.members.get(target_key): - target_provenance.members[target_key] = source_provenance.members[source_key].clone() +# target (Node): A composite list +# source (Node): A composite list +# +def _compose_composite_list(target, source): + clobber = source[0].get("(=)") + prefix = source[0].get("(<)") + suffix = source[0].get("(>)") + if clobber is not None: + # We want to clobber the target list + # which basically means replacing the target list + # with ourselves + target[0]["(=)"] = clobber + if prefix is not None: + target[0]["(<)"] = prefix + elif "(<)" in target[0]: + target[0]["(<)"][0].clear() + if suffix is not None: + target[0]["(>)"] = suffix + elif "(>)" in target[0]: + target[0]["(>)"][0].clear() else: - target_provenance.members[target_key].elements.extend([ - p.clone() for p in source_provenance.members[source_key].elements - ]) - - return True - - -# composite_list_overwrite -# -# Internal helper for list composition -# -# Args: -# target_node (dict): A simple dictionary -# target_key (dict): The key indicating a literal array to overwrite -# source_node (dict): Another simple dictionary -# source_key (str): The key indicating an array to overwrite the target with -# -# Returns: -# (bool): True if a source list was found and compositing occurred -# -def composite_list_overwrite(target_node, target_key, source_node, source_key): - - # We need to handle the legitimate case of overwriting a list with an empty - # list, hence the slightly odd default_value of [None] rather than []. - source_list = node_get(source_node, list, source_key, default_value=[None]) - if source_list == [None]: - return False - - target_provenance = node_get_provenance(target_node) - source_provenance = node_get_provenance(source_node) - - target_node[target_key] = list_copy(source_list) - target_provenance.members[target_key] = source_provenance.members[source_key].clone() - - return True + # Not clobbering, so prefix the prefix and suffix the suffix + if prefix is not None: + if "(<)" in target[0]: + for v in reversed(prefix[0]): + target[0]["(<)"][0].insert(0, v) + else: + target[0]["(<)"] = prefix + if suffix is not None: + if "(>)" in target[0]: + target[0]["(>)"][0].extend(suffix[0]) + else: + target[0]["(>)"] = suffix -# composite_list(): +# _compose_list() # -# Composite the source value onto the target value, if either -# sides are lists, or dictionaries containing list compositing directives +# Compose a composite list (a dict with composition directives) on top of a +# simple list. # # Args: -# target_node (dict): A simple dictionary -# source_node (dict): Another simple dictionary -# key (str): The key to compose on +# target (Node): The target list to be composed into +# source (Node): The composition list to be composed from # -# Returns: -# (bool): True if both sides were logical lists -# -# Raises: -# (LoadError): If one side was a logical list and the other was not -# -def composite_list(target_node, source_node, key): - target_value = target_node.get(key) - source_value = source_node[key] - - target_key_provenance = node_get_provenance(target_node, key) - source_key_provenance = node_get_provenance(source_node, key) - - # Whenever a literal list is encountered in the source, it - # overwrites the target values and provenance completely. - # - if isinstance(source_value, list): - - source_provenance = node_get_provenance(source_node) - target_provenance = node_get_provenance(target_node) - - # Assert target type - if not (target_value is None or - isinstance(target_value, list) or - is_composite_list(target_value)): - raise LoadError(LoadErrorReason.INVALID_DATA, - "{}: List cannot overwrite value at: {}" - .format(source_key_provenance, target_key_provenance)) - - composite_list_overwrite(target_node, key, source_node, key) - return True - - # When a composite list is encountered in the source, then - # multiple outcomes can occur... - # - elif is_composite_list(source_value): - - # If there is nothing there, then the composite list - # is copied in it's entirety as is, and preserved - # for later composition - # - if target_value is None: - source_provenance = node_get_provenance(source_node) - target_provenance = node_get_provenance(target_node) - - target_node[key] = node_copy(source_value) - target_provenance.members[key] = source_provenance.members[key].clone() - - # If the target is a literal list, then composition - # occurs directly onto that target, leaving the target - # as a literal list to overwrite anything in later composition - # - elif isinstance(target_value, list): - composite_list_overwrite(target_node, key, source_value, '(=)') - composite_list_prepend(target_node, key, source_value, '(<)') - composite_list_append(target_node, key, source_value, '(>)') - - # If the target is a composite list, then composition - # occurs in the target composite list, and the composite - # target list is preserved in dictionary form for further - # composition. - # - elif is_composite_list(target_value): - - if composite_list_overwrite(target_value, '(=)', source_value, '(=)'): - - # When overwriting a target with composition directives, remove any - # existing prepend/append directives in the target before adding our own - target_provenance = node_get_provenance(target_value) +def _compose_list(target, source): + clobber = source[0].get("(=)") + prefix = source[0].get("(<)") + suffix = source[0].get("(>)") + if clobber is not None: + target[0].clear() + target[0].extend(clobber[0]) + if prefix is not None: + for v in reversed(prefix[0]): + target[0].insert(0, v) + if suffix is not None: + target[0].extend(suffix[0]) - for directive in ['(<)', '(>)']: - try: - del target_value[directive] - del target_provenance.members[directive] - except KeyError: - # Ignore errors from deletion of non-existing keys - pass - # Prepend to the target prepend array, and append to the append array - composite_list_prepend(target_value, '(<)', source_value, '(<)') - composite_list_append(target_value, '(>)', source_value, '(>)') - - else: - raise LoadError(LoadErrorReason.INVALID_DATA, - "{}: List cannot overwrite value at: {}" - .format(source_key_provenance, target_key_provenance)) - - # We handled list composition in some way - return True - - # Source value was not a logical list - return False - - -# composite_dict(): +# composite_dict() # -# Composites values in target with values from source +# Compose one mapping node onto another # # Args: -# target (dict): A simple dictionary -# source (dict): Another simple dictionary +# target (Node): The target to compose into +# source (Node): The source to compose from +# path (list): The path to the current composition node # # Raises: CompositeError # -# Unlike the dictionary update() method, nested values in source -# will not obsolete entire subdictionaries in target, instead both -# dictionaries will be recursed and a composition of both will result -# -# This is useful for overriding configuration files and element -# configurations. -# def composite_dict(target, source, path=None): - target_provenance = ensure_provenance(target) - source_provenance = ensure_provenance(source) - - for key, source_value in node_items(source): - - # Track the full path of keys, only for raising CompositeError - if path: - thispath = path + '.' + key - else: - thispath = key - - # Handle list composition separately - if composite_list(target, source, key): - continue - - target_value = target.get(key) - - if isinstance(source_value, collections.abc.Mapping): - - # Handle creating new dicts on target side - if target_value is None: - target_value = {} - target[key] = target_value - - # Give the new dict provenance - value_provenance = source_value.get(PROVENANCE_KEY) - if value_provenance: - target_value[PROVENANCE_KEY] = value_provenance.clone() - - # Add a new provenance member element to the containing dict - target_provenance.members[key] = source_provenance.members[key] - - if not isinstance(target_value, collections.abc.Mapping): - raise CompositeTypeError(thispath, type(target_value), type(source_value)) - - # Recurse into matching dictionary - composite_dict(target_value, source_value, path=thispath) - + if path is None: + path = [] + for k, v in source[0].items(): + path.append(k) + if type(v[0]) is list: + # List clobbers anything list-like + target_value = target[0].get(k) + if not (target_value is None or + type(target_value[0]) is list or + _is_composite_list(target_value)): + raise CompositeError(path, + "{}: List cannot overwrite {} at: {}" + .format(node_get_provenance(source, k), + k, + node_get_provenance(target, k))) + # Looks good, clobber it + target[0][k] = v + elif _is_composite_list(v): + if k not in target[0]: + # Composite list clobbers empty space + target[0][k] = v + elif type(target[0][k][0]) is list: + # Composite list composes into a list + _compose_list(target[0][k], v) + elif _is_composite_list(target[0][k]): + # Composite list merges into composite list + _compose_composite_list(target[0][k], v) + else: + # Else composing on top of normal dict or a scalar, so raise... + raise CompositeError(path, + "{}: Cannot compose lists onto {}".format( + node_get_provenance(v), + node_get_provenance(target[0][k]))) + elif type(v[0]) is dict: + # We're composing a dict into target now + if k not in target[0]: + # Target lacks a dict at that point, make a fresh one with + # the same provenance as the incoming dict + target[0][k] = Node({}, v[1], v[2], v[3]) + if type(target[0]) is not dict: + raise CompositeError(path, + "{}: Cannot compose dictionary onto {}".format( + node_get_provenance(v), + node_get_provenance(target[0][k]))) + composite_dict(target[0][k], v, path) else: - - if target_value is not None: - - # Exception here: depending on how strings were declared ruamel may - # use a different type, but for our purposes, any stringish type will do. - if not (is_ruamel_str(source_value) and is_ruamel_str(target_value)) \ - and not isinstance(source_value, type(target_value)): - raise CompositeTypeError(thispath, type(target_value), type(source_value)) - - # Overwrite simple values, lists and mappings have already been handled - target_provenance.members[key] = source_provenance.members[key].clone() - target[key] = source_value + target_value = target[0].get(k) + if target_value is not None and type(target_value[0]) is not str: + raise CompositeError(path, + "{}: Cannot compose scalar on non-scalar at {}".format( + node_get_provenance(v), + node_get_provenance(target[0][k]))) + target[0][k] = v + path.pop() # Like composite_dict(), but raises an all purpose LoadError for convenience # def composite(target, source): - assert hasattr(source, 'get') + assert type(source[0]) is dict + assert type(target[0]) is dict - source_provenance = node_get_provenance(source) try: composite_dict(target, source) - except CompositeTypeError as e: + except CompositeError as e: + source_provenance = node_get_provenance(source) error_prefix = "" if source_provenance: error_prefix = "{}: ".format(source_provenance) raise LoadError(LoadErrorReason.ILLEGAL_COMPOSITE, - "{}Expected '{}' type for configuration '{}', instead received '{}'" + "{}Failure composing {}: {}" .format(error_prefix, - e.expected_type.__name__, e.path, - e.actual_type.__name__)) from e + e.message)) from e # Like composite(target, source), but where target overrides source instead. @@ -809,64 +958,60 @@ def composite(target, source): def composite_and_move(target, source): composite(source, target) - to_delete = [key for key, _ in node_items(target) if key not in source] - for key, value in source.items(): - target[key] = value + to_delete = [key for key in target[0].keys() if key not in source[0]] + for key, value in source[0].items(): + target[0][key] = value for key in to_delete: - del target[key] - - -# SanitizedDict is an OrderedDict that is dumped as unordered mapping. -# This provides deterministic output for unordered mappings. -# -class SanitizedDict(collections.OrderedDict): - pass - - -RoundTripRepresenter.add_representer(SanitizedDict, - SafeRepresenter.represent_dict) + del target[0][key] # Types we can short-circuit in node_sanitize for speed. -__SANITIZE_SHORT_CIRCUIT_TYPES = (int, float, str, bool, tuple) +__SANITIZE_SHORT_CIRCUIT_TYPES = (int, float, str, bool) # node_sanitize() # -# Returnes an alphabetically ordered recursive copy +# Returns an alphabetically ordered recursive copy # of the source node with internal provenance information stripped. # # Only dicts are ordered, list elements are left in order. # -def node_sanitize(node): +def node_sanitize(node, *, dict_type=OrderedDict): + node_type = type(node) + + # If we have an unwrappable node, unwrap it + if node_type is Node: + node = node[0] + node_type = type(node) + # Short-circuit None which occurs ca. twice per element if node is None: return node - node_type = type(node) # Next short-circuit integers, floats, strings, booleans, and tuples if node_type in __SANITIZE_SHORT_CIRCUIT_TYPES: return node - # Now short-circuit lists. Note this is only for the raw list - # type, CommentedSeq and others get caught later. + + # Now short-circuit lists. elif node_type is list: - return [node_sanitize(elt) for elt in node] + return [node_sanitize(elt, dict_type=dict_type) for elt in node] # Finally dict, and other Mappings need special handling - if node_type is dict or isinstance(node, collections.abc.Mapping): - result = SanitizedDict() + elif node_type is dict: + result = dict_type() - key_list = [key for key, _ in node_items(node)] + key_list = [key for key, _ in node.items()] for key in sorted(key_list): - result[key] = node_sanitize(node[key]) + result[key] = node_sanitize(node[key], dict_type=dict_type) return result - # Catch the case of CommentedSeq and friends. This is more rare and so - # we keep complexity down by still using isinstance here. - elif isinstance(node, list): - return [node_sanitize(elt) for elt in node] - # Everything else (such as commented scalars) just gets returned as-is. + # Sometimes we're handed tuples and we can't be sure what they contain + # so we have to sanitize into them + elif node_type is tuple: + return tuple((node_sanitize(v, dict_type=dict_type) for v in node)) + + # Everything else just gets returned as-is. return node @@ -888,8 +1033,7 @@ def node_validate(node, valid_keys): # Probably the fastest way to do this: https://stackoverflow.com/a/23062482 valid_keys = set(valid_keys) - valid_keys.add(PROVENANCE_KEY) - invalid = next((key for key in node if key not in valid_keys), None) + invalid = next((key for key in node[0] if key not in valid_keys), None) if invalid: provenance = node_get_provenance(node, key=invalid) @@ -908,62 +1052,54 @@ def node_validate(node, valid_keys): # These types just have their value copied -__QUICK_TYPES = (str, bool, - yaml.scalarstring.PreservedScalarString, - yaml.scalarstring.SingleQuotedScalarString, - yaml.scalarstring.DoubleQuotedScalarString) - -# These types have to be iterated like a dictionary -__DICT_TYPES = (dict, yaml.comments.CommentedMap) - -# These types have to be iterated like a list -__LIST_TYPES = (list, yaml.comments.CommentedSeq) - -# These are the provenance types, which have to be cloned rather than any other -# copying tactic. -__PROVENANCE_TYPES = (Provenance, DictProvenance, MemberProvenance, ElementProvenance) +__QUICK_TYPES = (str, bool) # These are the directives used to compose lists, we need this because it's # slightly faster during the node_final_assertions checks __NODE_ASSERT_COMPOSITION_DIRECTIVES = ('(>)', '(<)', '(=)') +# node_copy() +# +# Make a deep copy of the given YAML node, preserving provenance. +# +# Args: +# source (Node): The YAML node to copy +# +# Returns: +# (Node): A deep copy of source with provenance preserved. +# def node_copy(source): copy = {} - for key, value in source.items(): - value_type = type(value) - if value_type in __DICT_TYPES: + for key, value in source[0].items(): + value_type = type(value[0]) + if value_type is dict: copy[key] = node_copy(value) - elif value_type in __LIST_TYPES: - copy[key] = list_copy(value) - elif value_type in __PROVENANCE_TYPES: - copy[key] = value.clone() + elif value_type is list: + copy[key] = _list_copy(value) elif value_type in __QUICK_TYPES: copy[key] = value else: raise ValueError("Unable to be quick about node_copy of {}".format(value_type)) - ensure_provenance(copy) - - return copy + return Node(copy, source[1], source[2], source[3]) -def list_copy(source): +# Internal function to help node_copy() but for lists. +def _list_copy(source): copy = [] - for item in source: - item_type = type(item) - if item_type in __DICT_TYPES: + for item in source[0]: + item_type = type(item[0]) + if item_type is dict: copy.append(node_copy(item)) - elif item_type in __LIST_TYPES: - copy.append(list_copy(item)) - elif item_type in __PROVENANCE_TYPES: - copy.append(item.clone()) + elif item_type is list: + copy.append(_list_copy(item)) elif item_type in __QUICK_TYPES: copy.append(item) else: raise ValueError("Unable to be quick about list_copy of {}".format(item_type)) - return copy + return Node(copy, source[1], source[2], source[3]) # node_final_assertions() @@ -978,7 +1114,9 @@ def list_copy(source): # (LoadError): If any assertions fail # def node_final_assertions(node): - for key, value in node_items(node): + assert type(node) is Node + + for key, value in node[0].items(): # Assert that list composition directives dont remain, this # indicates that the user intended to override a list which @@ -989,22 +1127,23 @@ def node_final_assertions(node): raise LoadError(LoadErrorReason.TRAILING_LIST_DIRECTIVE, "{}: Attempt to override non-existing list".format(provenance)) - value_type = type(value) + value_type = type(value[0]) - if value_type in __DICT_TYPES: + if value_type is dict: node_final_assertions(value) - elif value_type in __LIST_TYPES: - list_final_assertions(value) + elif value_type is list: + _list_final_assertions(value) -def list_final_assertions(values): - for value in values: - value_type = type(value) +# Helper function for node_final_assertions(), but for lists. +def _list_final_assertions(values): + for value in values[0]: + value_type = type(value[0]) - if value_type in __DICT_TYPES: + if value_type is dict: node_final_assertions(value) - elif value_type in __LIST_TYPES: - list_final_assertions(value) + elif value_type is list: + _list_final_assertions(value) # assert_symbol_name() @@ -1025,7 +1164,6 @@ def list_final_assertions(values): # Note that dashes are generally preferred for variable names and # usage in YAML, but things such as option names which will be # evaluated with jinja2 cannot use dashes. -# def assert_symbol_name(provenance, symbol_name, purpose, *, allow_dashes=True): valid_chars = string.digits + string.ascii_letters + '_' if allow_dashes: @@ -1051,3 +1189,229 @@ def assert_symbol_name(provenance, symbol_name, purpose, *, allow_dashes=True): raise LoadError(LoadErrorReason.INVALID_SYMBOL_NAME, message, detail=detail) + + +# node_find_target() +# +# Searches the given node tree for the given target node. +# +# This is typically used when trying to walk a path to a given node +# for the purpose of then modifying a similar tree of objects elsewhere +# +# Args: +# node (Node): The node at the root of the tree to search +# target (Node): The node you are looking for in that tree +# +# Returns: +# (list): A path from `node` to `target` or None if `target` is not in the subtree +def node_find_target(node, target): + assert type(node) is Node + assert type(target) is Node + + path = [] + if _walk_find_target(node, path, target): + return path + return None + + +# Helper for node_find_target() which walks a value +def _walk_find_target(node, path, target): + if node[1:] == target[1:]: + return True + elif type(node[0]) is dict: + return _walk_dict_node(node, path, target) + elif type(node[0]) is list: + return _walk_list_node(node, path, target) + return False + + +# Helper for node_find_target() which walks a list +def _walk_list_node(node, path, target): + for i, v in enumerate(node[0]): + path.append(i) + if _walk_find_target(v, path, target): + return True + del path[-1] + return False + + +# Helper for node_find_target() which walks a mapping +def _walk_dict_node(node, path, target): + for k, v in node[0].items(): + path.append(k) + if _walk_find_target(v, path, target): + return True + del path[-1] + return False + + +############################################################################### + +# Roundtrip code + +# Always represent things consistently: + +yaml.RoundTripRepresenter.add_representer(OrderedDict, + yaml.SafeRepresenter.represent_dict) + +# Always parse things consistently + +yaml.RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:int', + yaml.RoundTripConstructor.construct_yaml_str) +yaml.RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:float', + yaml.RoundTripConstructor.construct_yaml_str) +yaml.RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:bool', + yaml.RoundTripConstructor.construct_yaml_str) +yaml.RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:null', + yaml.RoundTripConstructor.construct_yaml_str) +yaml.RoundTripConstructor.add_constructor(u'tag:yaml.org,2002:timestamp', + yaml.RoundTripConstructor.construct_yaml_str) + + +# HardlineDumper +# +# This is a dumper used during roundtrip_dump which forces every scalar to be +# a plain string, in order to match the output format to the input format. +# +# If you discover something is broken, please add a test case to the roundtrip +# test in tests/internals/yaml/roundtrip-test.yaml +# +class HardlineDumper(yaml.RoundTripDumper): + def __init__(self, *args, **kwargs): + yaml.RoundTripDumper.__init__(self, *args, **kwargs) + # For each of YAML 1.1 and 1.2, force everything to be a plain string + for version in [(1, 1), (1, 2), None]: + self.add_version_implicit_resolver( + version, + u'tag:yaml.org,2002:str', + yaml.util.RegExp(r'.*'), + None) + + +# roundtrip_load() +# +# Load a YAML file into memory in a form which allows roundtripping as best +# as ruamel permits. +# +# Note, the returned objects can be treated as Mappings and Lists and Strings +# but replacing content wholesale with plain dicts and lists may result +# in a loss of comments and formatting. +# +# Args: +# filename (str): The file to load in +# allow_missing (bool): Optionally set this to True to allow missing files +# +# Returns: +# (Mapping): The loaded YAML mapping. +# +# Raises: +# (LoadError): If the file is missing, or a directory, this is raised. +# Also if the YAML is malformed. +# +def roundtrip_load(filename, *, allow_missing=False): + try: + with open(filename, "r") as fh: + data = fh.read() + contents = roundtrip_load_data(data, filename=filename) + except FileNotFoundError as e: + if allow_missing: + # Missing files are always empty dictionaries + return {} + else: + raise LoadError(LoadErrorReason.MISSING_FILE, + "Could not find file at {}".format(filename)) from e + except IsADirectoryError as e: + raise LoadError(LoadErrorReason.LOADING_DIRECTORY, + "{} is a directory." + .format(filename)) from e + return contents + + +# roundtrip_load_data() +# +# Parse the given contents as YAML, returning them as a roundtrippable data +# structure. +# +# A lack of content will be returned as an empty mapping. +# +# Args: +# contents (str): The contents to be parsed as YAML +# filename (str): Optional filename to be used in error reports +# +# Returns: +# (Mapping): The loaded YAML mapping +# +# Raises: +# (LoadError): Raised on invalid YAML, or YAML which parses to something other +# than a Mapping +# +def roundtrip_load_data(contents, *, filename=None): + try: + contents = yaml.load(contents, yaml.RoundTripLoader, preserve_quotes=True) + except (yaml.scanner.ScannerError, yaml.composer.ComposerError, yaml.parser.ParserError) as e: + raise LoadError(LoadErrorReason.INVALID_YAML, + "Malformed YAML:\n\n{}\n\n{}\n".format(e.problem, e.problem_mark)) from e + + # Special case empty files at this point + if contents is None: + # We'll make them empty mappings like the main Node loader + contents = {} + + if not isinstance(contents, Mapping): + raise LoadError(LoadErrorReason.INVALID_YAML, + "YAML file has content of type '{}' instead of expected type 'dict': {}" + .format(type(contents).__name__, filename)) + + return contents + + +# roundtrip_dump() +# +# Dumps the given contents as a YAML file. Ideally the contents came from +# parsing with `roundtrip_load` or `roundtrip_load_data` so that they will be +# dumped in the same form as they came from. +# +# If `file` is a string, it is the filename to write to, if `file` has a +# `write` method, it's treated as a stream, otherwise output is to stdout. +# +# Args: +# contents (Mapping or list): The content to write out as YAML. +# file (any): The file to write to +# +def roundtrip_dump(contents, file=None): + assert type(contents) is not Node + + def stringify_dict(thing): + for k, v in thing.items(): + if type(v) is str: + pass + elif isinstance(v, Mapping): + stringify_dict(v) + elif isinstance(v, Sequence): + stringify_list(v) + else: + thing[k] = str(v) + + def stringify_list(thing): + for i, v in enumerate(thing): + if type(v) is str: + pass + elif isinstance(v, Mapping): + stringify_dict(v) + elif isinstance(v, Sequence): + stringify_list(v) + else: + thing[i] = str(v) + + contents = deepcopy(contents) + stringify_dict(contents) + + with ExitStack() as stack: + if type(file) is str: + from . import utils + f = stack.enter_context(utils.save_file_atomic(file, 'w')) + elif hasattr(file, 'write'): + f = file + else: + f = sys.stdout + yaml.round_trip_dump(contents, f, Dumper=HardlineDumper) |