diff options
Diffstat (limited to 'src/buildstream/node.pyx')
-rw-r--r-- | src/buildstream/node.pyx | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/buildstream/node.pyx b/src/buildstream/node.pyx index ea63151b9..98a785868 100644 --- a/src/buildstream/node.pyx +++ b/src/buildstream/node.pyx @@ -329,6 +329,45 @@ cdef class ScalarNode(Node): .format(provenance, path, bool.__name__, self.value), LoadErrorReason.INVALID_DATA) + cpdef object as_enum(self, object constraint): + """Get the value of the node as an enum member from `constraint` + + The constraint must be a :class:`buildstream.types.FastEnum` or a plain python Enum. + + For example you could do: + + .. code-block:: python + + from buildstream.types import FastEnum + + class SupportedCompressions(FastEnum): + NONE = "none" + GZIP = "gzip" + XZ = "xz" + + + x = config.get_scalar('compress').as_enum(SupportedCompressions) + + if x == SupportedCompressions.GZIP: + print("Using GZIP") + + Args: + constraint (:class:`buildstream.types.FastEnum` or :class:`Enum`): an enum from which to extract the value + for the current node. + + Returns: + :class:`FastEnum` or :class:`Enum`: the value contained in the node, as a member of `constraint` + """ + try: + return constraint(self.value) + except ValueError: + provenance = self.get_provenance() + path = provenance._toplevel._find(self)[-1] + valid_values = [str(v.value) for v in constraint] + raise LoadError("{}: Value of '{}' should be one of '{}'".format( + provenance, path, ", ".join(valid_values)), + LoadErrorReason.INVALID_DATA) + cpdef int as_int(self) except *: """Get the value of the node as an integer. @@ -511,6 +550,44 @@ cdef class MappingNode(Node): cdef ScalarNode scalar = self.get_scalar(key, default) return scalar.as_bool() + cpdef object get_enum(self, str key, object constraint, object default=_sentinel): + """Get the value of the node as an enum member from `constraint` + + Args: + key (str): key for which to get the value + constraint (:class:`buildstream.types.FastEnum` or :class:`Enum`): an enum from which to extract the value + for the current node. + default (object): default value to return if `key` is not in the mapping + + Raises: + :class:`buildstream._exceptions.LoadError`: if the value is not is not found or not part of the + provided enum. + + Returns: + :class:`buildstream.types.Enum` or :class:`Enum`: the value contained in the node, as a member of + `constraint` + """ + cdef object value = self.value.get(key, _sentinel) + + if value is _sentinel: + if default is _sentinel: + provenance = self.get_provenance() + raise LoadError("{}: Dictionary did not contain expected key '{}'".format(provenance, key), + LoadErrorReason.INVALID_DATA) + + if default is None: + return None + else: + return constraint(default) + + if type(value) is not ScalarNode: + provenance = value.get_provenance() + raise LoadError("{}: Value of '{}' is not of the expected type 'scalar'" + .format(provenance, key), + LoadErrorReason.INVALID_DATA) + + return (<ScalarNode> value).as_enum(constraint) + cpdef int get_int(self, str key, object default=_sentinel) except *: """get_int(key, default=sentinel) |