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python_types.py
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python_types.py
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"""
Backend for generating Python types that match the spec.
"""
from __future__ import absolute_import, division, print_function, unicode_literals
import itertools
import os
import re
import shutil
_MYPY = False
if _MYPY:
import typing # noqa: F401 # pylint: disable=import-error,unused-import,useless-suppression
# Hack to get around some of Python 2's standard library modules that
# accept ascii-encodable unicode literals in lieu of strs, but where
# actually passing such literals results in errors with mypy --py2. See
# <https://github.com/python/typeshed/issues/756> and
# <https://github.com/python/mypy/issues/2536>.
import importlib
argparse = importlib.import_module(str('argparse')) # type: typing.Any
from stone.ir import AnnotationType, ApiNamespace # noqa: F401 # pylint: disable=unused-import
from stone.ir import (
get_custom_annotations_for_alias,
get_custom_annotations_recursive,
is_alias,
is_boolean_type,
is_bytes_type,
is_list_type,
is_map_type,
is_nullable_type,
is_numeric_type,
is_string_type,
is_struct_type,
is_tag_ref,
is_timestamp_type,
is_union_type,
is_user_defined_type,
is_void_type,
RedactedBlot,
RedactedHash,
Struct,
Union,
unwrap,
unwrap_aliases,
unwrap_nullable,
)
from stone.ir import DataType # noqa: F401 # pylint: disable=unused-import
from stone.backend import CodeBackend
from stone.backends.python_helpers import (
class_name_for_annotation_type,
class_name_for_data_type,
check_route_name_conflict,
emit_pass_if_nothing_emitted,
fmt_class,
fmt_func,
fmt_namespace,
fmt_namespaced_var,
fmt_obj,
fmt_var,
generate_imports_for_referenced_namespaces,
generate_module_header,
validators_import,
)
from stone.backends.python_type_mapping import map_stone_type_to_python_type
# Matches format of Stone doc tags
doc_sub_tag_re = re.compile(':(?P<tag>[A-z]*):`(?P<val>.*?)`')
_cmdline_parser = argparse.ArgumentParser(prog='python-types-backend')
_cmdline_parser.add_argument(
'-r',
'--route-method',
help=('A string used to construct the location of a Python method for a '
'given route; use {ns} as a placeholder for namespace name and '
'{route} for the route name. This is used to translate Stone doc '
'references to routes to references in Python docstrings.'),
)
class PythonTypesBackend(CodeBackend):
"""Generates Python modules to represent the input Stone spec."""
cmdline_parser = _cmdline_parser
# Instance var of the current namespace being generated
cur_namespace = None # type: typing.Optional[ApiNamespace]
preserve_aliases = True
def generate(self, api):
"""
Generates a module for each namespace.
Each namespace will have Python classes to represent data types and
routes in the Stone spec.
"""
rsrc_folder = os.path.join(os.path.dirname(__file__), 'python_rsrc')
self.logger.info('Copying stone_validators.py to output folder')
shutil.copy(os.path.join(rsrc_folder, 'stone_validators.py'),
self.target_folder_path)
self.logger.info('Copying stone_serializers.py to output folder')
shutil.copy(os.path.join(rsrc_folder, 'stone_serializers.py'),
self.target_folder_path)
self.logger.info('Copying stone_base.py to output folder')
shutil.copy(os.path.join(rsrc_folder, 'stone_base.py'),
self.target_folder_path)
for namespace in api.namespaces.values():
reserved_namespace_name = fmt_namespace(namespace.name)
with self.output_to_relative_path('{}.py'.format(reserved_namespace_name)):
self._generate_base_namespace_module(api, namespace)
if reserved_namespace_name != namespace.name:
with self.output_to_relative_path('{}.py'.format(namespace.name)):
self._generate_dummy_namespace_module(reserved_namespace_name)
def _generate_base_namespace_module(self, api, namespace):
"""Creates a module for the namespace. All data types and routes are
represented as Python classes."""
self.cur_namespace = namespace
generate_module_header(self)
if namespace.doc is not None:
self.emit('"""')
self.emit_raw(namespace.doc)
self.emit('"""')
self.emit()
self.emit_raw(validators_import)
# Generate import statements for all referenced namespaces.
self._generate_imports_for_referenced_namespaces(namespace)
for annotation_type in namespace.annotation_types:
self._generate_annotation_type_class(namespace, annotation_type)
for data_type in namespace.linearize_data_types():
if isinstance(data_type, Struct):
self._generate_struct_class(namespace, data_type)
elif isinstance(data_type, Union):
self._generate_union_class(namespace, data_type)
else:
raise TypeError('Cannot handle type %r' % type(data_type))
for alias in namespace.linearize_aliases():
self._generate_alias_definition(namespace, alias)
# Generate the struct->subtype tag mapping at the end so that
# references to later-defined subtypes don't cause errors.
for data_type in namespace.linearize_data_types():
if is_struct_type(data_type):
self._generate_struct_class_reflection_attributes(
namespace, data_type)
if data_type.has_enumerated_subtypes():
self._generate_enumerated_subtypes_tag_mapping(
namespace, data_type)
elif is_union_type(data_type):
self._generate_union_class_reflection_attributes(
namespace, data_type)
self._generate_union_class_symbol_creators(data_type)
self._generate_routes(api.route_schema, namespace)
def _generate_dummy_namespace_module(self, reserved_namespace_name):
generate_module_header(self)
self.emit('# If you have issues importing this module because Python recognizes it as a '
'keyword, use {} instead.'.format(reserved_namespace_name))
self.emit('from .{} import *'.format(reserved_namespace_name))
def _generate_alias_definition(self, namespace, alias):
v = generate_validator_constructor(namespace, alias.data_type)
if alias.doc:
self.emit_wrapped_text(
self.process_doc(alias.doc, self._docf), prefix='# ')
validator_name = '{}_validator'.format(alias.name)
self.emit('{} = {}'.format(validator_name, v))
if alias.redactor:
self._generate_redactor(validator_name, alias.redactor)
unwrapped_dt, _ = unwrap_aliases(alias)
if is_user_defined_type(unwrapped_dt):
# If the alias is to a composite type, we want to alias the
# generated class as well.
self.emit('{} = {}'.format(
alias.name,
class_name_for_data_type(alias.data_type, namespace)))
def _generate_imports_for_referenced_namespaces(self, namespace):
# type: (ApiNamespace) -> None
generate_imports_for_referenced_namespaces(
backend=self,
namespace=namespace
)
def _docf(self, tag, val):
"""
Callback used as the handler argument to process_docs(). This converts
Stone doc references to Sphinx-friendly annotations.
"""
if tag == 'type':
return ':class:`{}`'.format(val)
elif tag == 'route':
if self.args.route_method:
return ':meth:`%s`' % self.args.route_method.format(
ns=self.cur_namespace.name, route=fmt_func(val))
else:
return val
elif tag == 'link':
anchor, link = val.rsplit(' ', 1)
return '`{} <{}>`_'.format(anchor, link)
elif tag == 'val':
if val == 'null':
return 'None'
elif val == 'true' or val == 'false':
return '``{}``'.format(val.capitalize())
else:
return val
elif tag == 'field':
return '``{}``'.format(val)
else:
raise RuntimeError('Unknown doc ref tag %r' % tag)
def _python_type_mapping(self, ns, data_type):
# type: (ApiNamespace, DataType) -> typing.Text
"""Map Stone data types to their most natural equivalent in Python
for documentation purposes."""
return map_stone_type_to_python_type(ns, data_type)
def _class_declaration_for_type(self, ns, data_type):
assert is_user_defined_type(data_type), \
'Expected struct, got %r' % type(data_type)
if data_type.parent_type:
extends = class_name_for_data_type(data_type.parent_type, ns)
else:
if is_struct_type(data_type):
# Use a handwritten base class
extends = 'bb.Struct'
elif is_union_type(data_type):
extends = 'bb.Union'
else:
extends = 'object'
return 'class {}({}):'.format(
class_name_for_data_type(data_type), extends)
#
# Annotation types
#
def _generate_annotation_type_class(self, ns, annotation_type):
# type: (ApiNamespace, AnnotationType) -> None
"""Defines a Python class that represents an annotation type in Stone."""
self.emit('class {}(bb.AnnotationType):'.format(
class_name_for_annotation_type(annotation_type, ns)))
with self.indent():
if annotation_type.has_documented_type_or_params():
self.emit('"""')
if annotation_type.doc:
self.emit_wrapped_text(
self.process_doc(annotation_type.doc, self._docf))
if annotation_type.has_documented_params():
self.emit()
for param in annotation_type.params:
if not param.doc:
continue
self.emit_wrapped_text(':ivar {}: {}'.format(
fmt_var(param.name, True),
self.process_doc(param.doc, self._docf)),
subsequent_prefix=' ')
self.emit('"""')
self.emit()
self._generate_annotation_type_class_slots(annotation_type)
self._generate_annotation_type_class_init(ns, annotation_type)
self._generate_annotation_type_class_properties(ns, annotation_type)
self.emit()
def _generate_annotation_type_class_slots(self, annotation_type):
# type: (AnnotationType) -> None
with self.block('__slots__ =', delim=('[', ']')):
for param in annotation_type.params:
param_name = fmt_var(param.name, True)
self.emit("'_{}',".format(param_name))
self.emit()
def _generate_annotation_type_class_init(self, ns, annotation_type):
# type: (ApiNamespace, AnnotationType) -> None
args = ['self']
for param in annotation_type.params:
param_name = fmt_var(param.name, True)
default_value = (self._generate_python_value(ns, param.default)
if param.has_default else 'None')
args.append('{}={}'.format(param_name, default_value))
self.generate_multiline_list(args, before='def __init__', after=':')
with self.indent():
for param in annotation_type.params:
self.emit('self._{0} = {0}'.format(fmt_var(param.name, True)))
self.emit()
def _generate_annotation_type_class_properties(self, ns, annotation_type):
# type: (ApiNamespace, AnnotationType) -> None
for param in annotation_type.params:
param_name = fmt_var(param.name, True)
prop_name = fmt_func(param.name, True)
self.emit('@property')
self.emit('def {}(self):'.format(prop_name))
with self.indent():
self.emit('"""')
if param.doc:
self.emit_wrapped_text(
self.process_doc(param.doc, self._docf))
# Sphinx wants an extra line between the text and the
# rtype declaration.
self.emit()
self.emit(':rtype: {}'.format(
self._python_type_mapping(ns, param.data_type)))
self.emit('"""')
self.emit('return self._{}'.format(param_name))
self.emit()
#
# Struct Types
#
def _generate_struct_class(self, ns, data_type):
# type: (ApiNamespace, Struct) -> None
"""Defines a Python class that represents a struct in Stone."""
self.emit(self._class_declaration_for_type(ns, data_type))
with self.indent():
if data_type.has_documented_type_or_fields():
self.emit('"""')
if data_type.doc:
self.emit_wrapped_text(
self.process_doc(data_type.doc, self._docf))
if data_type.has_documented_fields():
self.emit()
for field in data_type.fields:
if not field.doc:
continue
self.emit_wrapped_text(':ivar {}: {}'.format(
fmt_namespaced_var(ns.name, data_type.name, field.name),
self.process_doc(field.doc, self._docf)),
subsequent_prefix=' ')
self.emit('"""')
self.emit()
self._generate_struct_class_slots(data_type)
self._generate_struct_class_has_required_fields(data_type)
self._generate_struct_class_init(data_type)
self._generate_struct_class_properties(ns, data_type)
self._generate_struct_class_custom_annotations(ns, data_type)
self._generate_struct_class_repr(data_type)
if data_type.has_enumerated_subtypes():
validator = 'StructTree'
else:
validator = 'Struct'
self.emit('{0}_validator = bv.{1}({0})'.format(
class_name_for_data_type(data_type),
validator,
))
self.emit()
def _func_args_from_dict(self, d):
"""Given a Python dictionary, creates a string representing arguments
for invoking a function. All arguments with a value of None are
ignored."""
filtered_d = self.filter_out_none_valued_keys(d)
return ', '.join(['%s=%s' % (k, v) for k, v in filtered_d.items()])
def _generate_struct_class_slots(self, data_type):
"""Creates a slots declaration for struct classes.
Slots are an optimization in Python. They reduce the memory footprint
of instances since attributes cannot be added after declaration.
"""
with self.block('__slots__ =', delim=('[', ']')):
for field in data_type.fields:
field_name = fmt_var(field.name)
self.emit("'_%s_value'," % field_name)
self.emit("'_%s_present'," % field_name)
self.emit()
def _generate_struct_class_has_required_fields(self, data_type):
has_required_fields = len(data_type.all_required_fields) > 0
self.emit('_has_required_fields = %r' % has_required_fields)
self.emit()
def _generate_struct_class_reflection_attributes(self, ns, data_type):
"""
Generates two class attributes:
* _all_field_names_: Set of all field names including inherited fields.
* _all_fields_: List of tuples, where each tuple is (name, validator).
If a struct has enumerated subtypes, then two additional attributes are
generated:
* _field_names_: Set of all field names excluding inherited fields.
* _fields: List of tuples, where each tuple is (name, validator), and
excludes inherited fields.
These are needed because serializing a struct with enumerated subtypes
requires knowing the fields defined in each level of the hierarchy.
"""
class_name = class_name_for_data_type(data_type)
if data_type.parent_type:
parent_type_class_name = class_name_for_data_type(
data_type.parent_type, ns)
else:
parent_type_class_name = None
for field in data_type.fields:
field_name = fmt_var(field.name)
validator_name = generate_validator_constructor(ns, field.data_type)
full_validator_name = '{}._{}_validator'.format(class_name, field_name)
self.emit('{} = {}'.format(full_validator_name, validator_name))
if field.redactor:
self._generate_redactor(full_validator_name, field.redactor)
# Generate `_all_field_names_` and `_all_fields_` for every omitted caller (and public).
# As an edge case, we union omitted callers with None in the case when the object has no
# public fields, as we still need to generate public attributes (`_field_names_` etc)
child_omitted_callers = data_type.get_all_omitted_callers() | {None}
parent_omitted_callers = data_type.parent_type.get_all_omitted_callers() if \
data_type.parent_type else set([])
for omitted_caller in sorted(child_omitted_callers | parent_omitted_callers, key=str):
is_public = omitted_caller is None
map_name_prefix = '' if is_public else '_{}'.format(omitted_caller)
caller_in_parent = data_type.parent_type and (is_public or omitted_caller
in parent_omitted_callers)
# generate `_all_field_names_`
names_map_name = '{}_field_names_'.format(map_name_prefix)
all_names_map_name = '_all{}_field_names_'.format(map_name_prefix)
if data_type.is_member_of_enumerated_subtypes_tree():
if is_public or omitted_caller in child_omitted_callers:
self.generate_multiline_list(
[
"'%s'" % field.name
for field in data_type.fields
if field.omitted_caller == omitted_caller
],
before='{}.{} = set('.format(class_name, names_map_name),
after=')',
delim=('[', ']'),
compact=False)
if caller_in_parent:
self.emit('{0}.{3} = {1}.{3}.union({0}.{2})'
.format(class_name, parent_type_class_name, names_map_name,
all_names_map_name))
else:
self.emit('{0}.{2} = {0}.{1}'.format(class_name, names_map_name,
all_names_map_name))
else:
if caller_in_parent:
before = '{0}.{1} = {2}.{1}.union(set('.format(class_name, all_names_map_name,
parent_type_class_name)
after = '))'
else:
before = '{}.{} = set('.format(class_name, all_names_map_name)
after = ')'
items = [
"'%s'" % field.name
for field in data_type.fields
if field.omitted_caller == omitted_caller
]
self.generate_multiline_list(
items,
before=before,
after=after,
delim=('[', ']'),
compact=False)
# generate `_all_fields_`
fields_map_name = '{}_fields_'.format(map_name_prefix)
all_fields_map_name = '_all{}_fields_'.format(map_name_prefix)
if data_type.is_member_of_enumerated_subtypes_tree():
items = []
for field in data_type.fields:
if field.omitted_caller != omitted_caller:
continue
var_name = fmt_var(field.name)
validator_name = '{}._{}_validator'.format(class_name,
var_name)
items.append("('{}', {})".format(var_name, validator_name))
self.generate_multiline_list(
items,
before='{}.{} = '.format(class_name, fields_map_name),
delim=('[', ']'),
compact=False,
)
if caller_in_parent:
self.emit('{0}.{3} = {1}.{3} + {0}.{2}'.format(
class_name, parent_type_class_name, fields_map_name, all_fields_map_name))
else:
self.emit('{0}.{2} = {0}.{1}'.format(
class_name, fields_map_name, all_fields_map_name))
else:
if caller_in_parent:
before = '{0}.{2} = {1}.{2} + '.format(
class_name, parent_type_class_name, all_fields_map_name)
else:
before = '{}.{} = '.format(class_name, all_fields_map_name)
items = []
for field in data_type.fields:
if field.omitted_caller != omitted_caller:
continue
var_name = fmt_var(field.name)
validator_name = '{}._{}_validator'.format(
class_name, var_name)
items.append("('{}', {})".format(var_name, validator_name))
self.generate_multiline_list(
items, before=before, delim=('[', ']'), compact=False)
self.emit()
def _generate_struct_class_init(self, data_type):
"""
Generates constructor. The constructor takes all possible fields as
optional arguments. Any argument that is set on construction sets the
corresponding field for the instance.
"""
args = ['self']
for field in data_type.all_fields:
field_name_reserved_check = fmt_var(field.name, True)
args.append('%s=None' % field_name_reserved_check)
self.generate_multiline_list(args, before='def __init__', after=':')
with self.indent():
lineno = self.lineno
# Call the parent constructor if a super type exists
if data_type.parent_type:
class_name = class_name_for_data_type(data_type)
all_parent_fields = [fmt_func(f.name, check_reserved=True)
for f in data_type.parent_type.all_fields]
self.generate_multiline_list(
all_parent_fields,
before='super({}, self).__init__'.format(class_name))
# initialize each field
for field in data_type.fields:
field_var_name = fmt_var(field.name)
self.emit('self._{}_value = None'.format(field_var_name))
self.emit('self._{}_present = False'.format(field_var_name))
# handle arguments that were set
for field in data_type.fields:
field_var_name = fmt_var(field.name, True)
self.emit('if {} is not None:'.format(field_var_name))
with self.indent():
self.emit('self.{0} = {0}'.format(field_var_name))
if lineno == self.lineno:
self.emit('pass')
self.emit()
def _generate_python_value(self, ns, value):
if is_tag_ref(value):
ref = '{}.{}'.format(class_name_for_data_type(value.union_data_type),
fmt_var(value.tag_name))
if ns != value.union_data_type.namespace:
ref = '{}.{}'.format(fmt_namespace(value.union_data_type.namespace.name), ref)
return ref
else:
return fmt_obj(value)
def _generate_struct_class_properties(self, ns, data_type):
"""
Each field of the struct has a corresponding setter and getter.
The setter validates the value being set.
"""
for field in data_type.fields:
field_name = fmt_func(field.name)
field_name_reserved_check = fmt_func(field.name, check_reserved=True)
if is_nullable_type(field.data_type):
field_dt = field.data_type.data_type
dt_nullable = True
else:
field_dt = field.data_type
dt_nullable = False
# generate getter for field
self.emit('@property')
self.emit('def {}(self):'.format(field_name_reserved_check))
with self.indent():
self.emit('"""')
if field.doc:
self.emit_wrapped_text(
self.process_doc(field.doc, self._docf))
# Sphinx wants an extra line between the text and the
# rtype declaration.
self.emit()
self.emit(':rtype: {}'.format(
self._python_type_mapping(ns, field_dt)))
self.emit('"""')
self.emit('if self._{}_present:'.format(field_name))
with self.indent():
self.emit('return self._{}_value'.format(field_name))
self.emit('else:')
with self.indent():
if dt_nullable:
self.emit('return None')
elif field.has_default:
self.emit('return {}'.format(
self._generate_python_value(ns, field.default)))
else:
self.emit(
"raise AttributeError(\"missing required field '%s'\")"
% field_name
)
self.emit()
# generate setter for field
self.emit('@{}.setter'.format(field_name_reserved_check))
self.emit('def {}(self, val):'.format(field_name_reserved_check))
with self.indent():
if dt_nullable:
self.emit('if val is None:')
with self.indent():
self.emit('del self.{}'.format(field_name_reserved_check))
self.emit('return')
if is_user_defined_type(field_dt):
self.emit('self._%s_validator.validate_type_only(val)' %
field_name)
else:
self.emit('val = self._{}_validator.validate(val)'.format(field_name))
self.emit('self._{}_value = val'.format(field_name))
self.emit('self._{}_present = True'.format(field_name))
self.emit()
# generate deleter for field
self.emit('@{}.deleter'.format(field_name_reserved_check))
self.emit('def {}(self):'.format(field_name_reserved_check))
with self.indent():
self.emit('self._{}_value = None'.format(field_name))
self.emit('self._{}_present = False'.format(field_name))
self.emit()
def _generate_custom_annotation_instance(self, ns, annotation):
"""
Generates code to construct an instance of an annotation type object
with parameters from the specified annotation.
"""
annotation_class = class_name_for_annotation_type(annotation.annotation_type, ns)
return generate_func_call(
annotation_class,
kwargs=((fmt_var(k, True), self._generate_python_value(ns, v))
for k, v in annotation.kwargs.items())
)
def _generate_custom_annotation_processors(self, ns, data_type, extra_annotations=()):
"""
Generates code that will run a custom function 'processor' on every
field with a custom annotation, no matter how deep (recursively) it
might be located in data_type (incl. in elements of lists or maps).
If extra_annotations is passed, it's assumed to be a list of custom
annotation applied directly onto data_type (e.g. because it's a field
in a struct).
Yields pairs of (annotation_type, code) where code is code that
evaluates to a function that should be executed with an instance of
data_type as the only parameter, and whose return value should replace
that instance.
"""
# annotations applied to members of this type
dt, _, _ = unwrap(data_type)
if is_struct_type(dt) or is_union_type(dt):
annotation_types_seen = set()
for annotation in get_custom_annotations_recursive(dt):
if annotation.annotation_type not in annotation_types_seen:
yield (annotation.annotation_type,
generate_func_call(
'bb.make_struct_annotation_processor',
args=[class_name_for_annotation_type(annotation.annotation_type, ns),
'processor']
))
annotation_types_seen.add(annotation.annotation_type)
elif is_list_type(dt):
for annotation_type, recursive_processor in self._generate_custom_annotation_processors(
ns, dt.data_type):
# every member needs to be replaced---use handwritten processor
yield (annotation_type,
generate_func_call(
'bb.make_list_annotation_processor',
args=[recursive_processor]
))
elif is_map_type(dt):
for annotation_type, recursive_processor in self._generate_custom_annotation_processors(
ns, dt.value_data_type):
# every value needs to be replaced---use handwritten processor
yield (annotation_type,
generate_func_call(
'bb.make_map_value_annotation_processor',
args=[recursive_processor]
))
# annotations applied directly to this type (through aliases or
# passed in from the caller)
for annotation in itertools.chain(get_custom_annotations_for_alias(data_type),
extra_annotations):
yield (annotation.annotation_type,
generate_func_call(
'bb.partially_apply',
args=['processor', self._generate_custom_annotation_instance(ns, annotation)]
))
def _generate_struct_class_custom_annotations(self, ns, data_type):
"""
The _process_custom_annotations function allows client code to access
custom annotations defined in the spec.
"""
self.emit('def _process_custom_annotations(self, annotation_type, field_path, processor):')
with self.indent(), emit_pass_if_nothing_emitted(self):
self.emit(
(
'super({}, self)._process_custom_annotations(annotation_type, field_path, '
'processor)'
).format(class_name_for_data_type(data_type))
)
self.emit()
for field in data_type.fields:
field_name = fmt_var(field.name, check_reserved=True)
for annotation_type, processor in self._generate_custom_annotation_processors(
ns, field.data_type, field.custom_annotations):
annotation_class = class_name_for_annotation_type(annotation_type, ns)
self.emit('if annotation_type is {}:'.format(annotation_class))
with self.indent():
self.emit('self.{} = {}'.format(
field_name,
generate_func_call(
processor,
args=[
"'{{}}.{}'.format(field_path)".format(field_name),
'self.{}'.format(field_name),
])
))
self.emit()
def _generate_struct_class_repr(self, data_type):
"""
Generates something like:
def __repr__(self):
return 'Employee(first_name={!r}, last_name={!r}, age={!r})'.format(
self._first_name_value,
self._last_name_value,
self._age_value,
)
"""
self.emit('def __repr__(self):')
with self.indent():
if data_type.all_fields:
constructor_kwargs_fmt = ', '.join(
'{}={{!r}}'.format(fmt_var(f.name, True))
for f in data_type.all_fields)
self.emit("return '{}({})'.format(".format(
class_name_for_data_type(data_type),
constructor_kwargs_fmt,
))
with self.indent():
for f in data_type.all_fields:
self.emit("self._{}_value,".format(fmt_var(f.name)))
self.emit(")")
else:
self.emit("return '%s()'" %
class_name_for_data_type(data_type))
self.emit()
def _generate_enumerated_subtypes_tag_mapping(self, ns, data_type):
"""
Generates attributes needed for serializing and deserializing structs
with enumerated subtypes. These assignments are made after all the
Python class definitions to ensure that all references exist.
"""
assert data_type.has_enumerated_subtypes()
# Generate _tag_to_subtype_ attribute: Map from string type tag to
# the validator of the referenced subtype. Used on deserialization
# to look up the subtype for a given tag.
tag_to_subtype_items = []
for tags, subtype in data_type.get_all_subtypes_with_tags():
tag_to_subtype_items.append("{}: {}".format(
tags,
generate_validator_constructor(ns, subtype)))
self.generate_multiline_list(
tag_to_subtype_items,
before='{}._tag_to_subtype_ = '.format(data_type.name),
delim=('{', '}'),
compact=False)
# Generate _pytype_to_tag_and_subtype_: Map from Python class to a
# tuple of (type tag, subtype). Used on serialization to lookup how a
# class should be encoded based on the root struct's enumerated
# subtypes.
items = []
for tag, subtype in data_type.get_all_subtypes_with_tags():
items.append("{0}: ({1}, {2})".format(
fmt_class(subtype.name),
tag,
generate_validator_constructor(ns, subtype)))
self.generate_multiline_list(
items,
before='{}._pytype_to_tag_and_subtype_ = '.format(data_type.name),
delim=('{', '}'),
compact=False)
# Generate _is_catch_all_ attribute:
self.emit('{}._is_catch_all_ = {!r}'.format(
data_type.name, data_type.is_catch_all()))
self.emit()
#
# Tagged Union Types
#
def _generate_union_class(self, ns, data_type):
# type: (ApiNamespace, Union) -> None
"""Defines a Python class that represents a union in Stone."""
self.emit(self._class_declaration_for_type(ns, data_type))
with self.indent():
self.emit('"""')
if data_type.doc:
self.emit_wrapped_text(
self.process_doc(data_type.doc, self._docf))
self.emit()
self.emit_wrapped_text(
'This class acts as a tagged union. Only one of the ``is_*`` '
'methods will return true. To get the associated value of a '
'tag (if one exists), use the corresponding ``get_*`` method.')
if data_type.has_documented_fields():
self.emit()
for field in data_type.fields:
if not field.doc:
continue
if is_void_type(field.data_type):
ivar_doc = ':ivar {}: {}'.format(
fmt_namespaced_var(ns.name, data_type.name, field.name),
self.process_doc(field.doc, self._docf))
elif is_user_defined_type(field.data_type):
if data_type.namespace.name != ns.name:
formatted_var = fmt_namespaced_var(ns.name, data_type.name, field.name)
else:
formatted_var = '{}.{}'.format(data_type.name, fmt_var(field.name))
ivar_doc = ':ivar {} {}: {}'.format(
fmt_class(field.data_type.name),
formatted_var,
self.process_doc(field.doc, self._docf))
else:
ivar_doc = ':ivar {} {}: {}'.format(
self._python_type_mapping(ns, field.data_type),
fmt_namespaced_var(ns.name, data_type.name, field.name), field.doc)
self.emit_wrapped_text(ivar_doc, subsequent_prefix=' ')
self.emit('"""')
self.emit()
self._generate_union_class_vars(data_type)
self._generate_union_class_variant_creators(ns, data_type)
self._generate_union_class_is_set(data_type)
self._generate_union_class_get_helpers(ns, data_type)
self._generate_union_class_custom_annotations(ns, data_type)
self._generate_union_class_repr(data_type)
self.emit('{0}_validator = bv.Union({0})'.format(
class_name_for_data_type(data_type)
))
self.emit()
def _generate_union_class_vars(self, data_type):
"""
Adds a _catch_all_ attribute to each class. Also, adds a placeholder
attribute for the construction of union members of void type.
"""
lineno = self.lineno
if data_type.catch_all_field:
self.emit("_catch_all = '%s'" % data_type.catch_all_field.name)
elif not data_type.parent_type:
self.emit('_catch_all = None')
# Generate stubs for class variables so that IDEs like PyCharms have an
# easier time detecting their existence.
for field in data_type.fields:
if is_void_type(field.data_type):
field_name = fmt_var(field.name)
self.emit('# Attribute is overwritten below the class definition')
self.emit('{} = None'.format(field_name))
if lineno != self.lineno:
self.emit()
def _generate_union_class_reflection_attributes(self, ns, data_type):
"""
Adds a class attribute for each union member assigned to a validator.
Also adds an attribute that is a map from tag names to validators.
"""
class_name = fmt_class(data_type.name)
for field in data_type.fields:
field_name = fmt_var(field.name)
validator_name = generate_validator_constructor(
ns, field.data_type)
full_validator_name = '{}._{}_validator'.format(class_name, field_name)
self.emit('{} = {}'.format(full_validator_name, validator_name))
if field.redactor:
self._generate_redactor(full_validator_name, field.redactor)
# generate _all_fields_ for each omitted caller (and public)
child_omitted_callers = data_type.get_all_omitted_callers()
parent_omitted_callers = data_type.parent_type.get_all_omitted_callers() if \
data_type.parent_type else set([])
all_omitted_callers = child_omitted_callers | parent_omitted_callers
if len(all_omitted_callers) != 0:
self.emit('{}._permissioned_tagmaps = {}'.format(class_name, all_omitted_callers))
for omitted_caller in sorted(all_omitted_callers | {None}, key=str):
is_public = omitted_caller is None
tagmap_name = '_tagmap' if is_public else '_{}_tagmap'.format(omitted_caller)
caller_in_parent = data_type.parent_type and (is_public or omitted_caller
in parent_omitted_callers)
with self.block('{}.{} ='.format(class_name, tagmap_name)):
for field in data_type.fields:
if field.omitted_caller != omitted_caller:
continue
var_name = fmt_var(field.name)
validator_name = '{}._{}_validator'.format(class_name, var_name)
self.emit("'{}': {},".format(var_name, validator_name))
if caller_in_parent:
self.emit('{0}.{1}.update({2}.{1})'.format(
class_name, tagmap_name,
class_name_for_data_type(data_type.parent_type, ns))
)
self.emit()
def _generate_union_class_variant_creators(self, ns, data_type):
"""
Each non-symbol, non-any variant has a corresponding class method that
can be used to construct a union with that variant selected.
"""
for field in data_type.fields:
if not is_void_type(field.data_type):
field_name = fmt_func(field.name)
field_name_reserved_check = fmt_func(field.name, check_reserved=True)
if is_nullable_type(field.data_type):
field_dt = field.data_type.data_type
else:
field_dt = field.data_type
self.emit('@classmethod')
self.emit('def {}(cls, val):'.format(field_name_reserved_check))
with self.indent():
self.emit('"""')
self.emit_wrapped_text(
'Create an instance of this class set to the ``%s`` '
'tag with value ``val``.' % field_name)
self.emit()
self.emit(':param {} val:'.format(
self._python_type_mapping(ns, field_dt)))
self.emit(':rtype: {}'.format(
self._python_type_mapping(ns, data_type)))
self.emit('"""')
self.emit("return cls('{}', val)".format(field_name))
self.emit()
def _generate_union_class_is_set(self, data_type):
for field in data_type.fields:
field_name = fmt_func(field.name)
self.emit('def is_{}(self):'.format(field_name))
with self.indent():
self.emit('"""')
self.emit('Check if the union tag is ``%s``.' % field_name)
self.emit()
self.emit(':rtype: bool')
self.emit('"""')
self.emit("return self._tag == '{}'".format(field_name))
self.emit()
def _generate_union_class_get_helpers(self, ns, data_type):
"""
These are the getters used to access the value of a variant, once
the tag has been switched on.
"""
for field in data_type.fields:
field_name = fmt_func(field.name)