def emit_union(m: Module, item: Item, *, resolver: Resolver) -> Definition:
typename = goname(item.type_.__name__)
kind_typename = typename + "Kind"
# type <typename> {
# Kind string `json:"$kind"`
# ...
# }
m.stmt(f"type {typename} struct {{")
with m.scope():
m.stmt(f'Kind {kind_typename} `json:"$kind"` // discriminator')
for subtype in item.args:
gotype: str = resolver.resolve_gotype(subtype)
m.append(f"{gotype} *{gotype}")
m.stmt(
f' `json:"{untitleize(str(gotype)).rstrip("_")},omitempty"`')
m.stmt("}")
m.sep()
# UnmarshalJSON
discriminator_field = ("$kind", typeinfo.typeinfo(str), metadata())
discriminator_field[-1]["_override_type"] = kind_typename
pseudo_fields = [(sub_type.__name__, typeinfo.typeinfo(sub_type),
metadata(required=False)) for sub_type in item.args]
pseudo_item = Item(
type_=item.type_,
fields=[discriminator_field] + pseudo_fields,
args=[],
)
unmarshalJSON_definition = emit_unmarshalJSON(m,
pseudo_item,
resolver=resolver)
m.sep()
# one-of validation
assert unmarshalJSON_definition.code_module is not None
this = m.symbol(f"{item.type_.__name__[0].lower()}")
maperr_pkg = m.import_("github.com/podhmo/maperr")
sm = unmarshalJSON_definition.code_module
sm.stmt("// one-of?")
sm.stmt("{")
with sm.scope():
for go_name, info, _ in pseudo_item.fields[1:]:
with sm.if_(
f'{this}.Kind == "{go_name}" && {this}.{go_name} == nil'):
sm.stmt(
f'err = err.Add("{go_name}", {maperr_pkg}.Message{{Text: "treated as {go_name}, but no data"}})'
)
sm.stmt("}")
# enums
emit_enums(m, item.type_, resolver=resolver, name=kind_typename)
definition = Definition(name=typename, code_module=None)
return definition
def visit(m: Module, *, names: t.List[str]) -> None:
m.stmt("func run() error {")
with m.scope():
m.stmt(f"return {names[0].split('.', 2)[-1]}()")
m.stmt("}")
m.sep()
for name, prev in itertools.zip_longest(names, names[1:]):
if prev is None:
visit_core(m, name=name)
else:
visit_wrap(m, name=name, prev=prev)
m.sep()
def emit_unmarshalJSON(m: Module, item: Item, *,
resolver: Resolver) -> Definition:
this = m.symbol(f"{item.type_.__name__[0].lower()}")
this_type = f"{resolver.resolve_gotype(item.type_)}"
this_type_pointer = f"*{this_type}"
# func (ob *Ob) UnmarshalJSON(b []byte) error {
b = m.symbol("b")
m.stmt(
f"func ({this} {this_type_pointer}) UnmarshalJSON({b} []byte) error {{"
)
with m.scope():
# var err *maperr.Error
err = m.symbol("err")
maperr_pkg = m.import_("github.com/podhmo/maperr")
m.stmt(f"var {err} *{maperr_pkg}.Error")
m.sep()
# var inner struct {
# ...
# }
m.stmt("// loading internal data")
inner = m.symbol("inner")
m.stmt(f"var {inner} struct {{")
with m.scope():
for name, info, metadata in item.fields:
if name.startswith("_"):
continue # xxx:
if "_override_type" in metadata:
gotype: str = metadata["_override_type"]
elif has_class_object(info):
json_pkg = m.import_("encoding/json")
gotype: str = str(json_pkg.RawMessage)
else:
gotype: str = resolver.resolve_gotype(info.raw)
m.append(f'{goname(name)} *{gotype} `json:"{name}"`')
m.stmt("// required" if metadata["required"] else "")
m.stmt("}")
# if rawErr := json.Unmarshal(b, &inner); rawErr != nil {
# ...
# }
json_pkg = m.import_("encoding/json")
raw_err = m.symbol("rawErr")
with m.if_(
f"{raw_err} := {json_pkg}.Unmarshal(b, &{inner}); {raw_err} != nil"
):
m.return_(err.AddSummary(raw_err.Error()))
m.sep()
# if <field> != nil {
# ob.<field> = *<field>
# } else {
# m.add(<field>, "required")
# }
rawerr = m.symbol("rawerr")
m.stmt("// binding field value and required check")
with m.block():
for name, info, metadata in item.fields:
field = m.symbol(goname(name))
with m.if_(f"{inner}.{field} != nil"):
if has_class_object(info):
# pointer
if info.is_optional:
gotype: str = resolver.resolve_gotype(
info.normalized)
m.stmt(f"{this}.{goname(name)} = &{gotype}{{}}")
ref = f"{this}.{field}"
elif hasattr(info, "args"): # xxx
gotype: str = resolver.resolve_gotype(
info.normalized)
m.stmt(f"{this}.{goname(name)} = {gotype}{{}}")
ref = f"&{this}.{field}"
else:
ref = f"&{this}.{field}"
with m.if_(
f"{rawerr} := json.Unmarshal(*{inner}.{field}, {ref}); {rawerr} != nil"
):
m.stmt(
f'{err} = {err}.Add("{name}", {maperr_pkg}.Message{{Error: {rawerr}}})'
)
else:
m.stmt(f"{this}.{field} = *{inner}.{field}")
if metadata["required"]:
with m.else_():
m.stmt(
f'{err} = err.Add("{name}", {maperr_pkg}.Message{{Text: "required"}})'
)
m.sep()
# NOTE: for injecting code from extrnal area
code_module = m.submodule("", newline=False)
# return err.Untyped()
m.return_(err.Untyped())
m.stmt("}")
return Definition(name="UnmarshalJSON", code_module=code_module)
def emit_enums(
m: Module,
literal_type: t.Type[t.Any],
*,
resolver: Resolver,
name: t.Optional[str] = None,
) -> str:
# literal_type or union_type
go_type = name or f"{resolver.resolve_gotype(literal_type)}"
first_of_args = t.get_args(literal_type)[0]
base_go_type = resolver.resolve_gotype(
type(getattr(first_of_args, "__name__", first_of_args)))
const_names = [getattr(x, "__name__", x) for x in t.get_args(literal_type)]
const_members = {name: f"{go_type}{goname(name)}" for name in const_names}
this = m.symbol("v")
as_literal = resolver.resolve_default
# type <enum> string
m.stmt(f"type {go_type} {base_go_type}")
m.sep()
# const (
# <enum>xxx <enum> = "xxx"
# ...
# )
with m.const_group() as cg:
for name in const_names:
cg(f"{const_members[name]} {go_type} = {as_literal(type(name), name)}"
)
m.sep()
# func (v <enum>) Valid() error {
# ...
# }
with m.method(f"{this} {go_type}", "Valid", returns="error"):
with m.switch(this) as sm:
with sm.case(", ".join(const_members.values())):
sm.return_("nil")
with sm.default() as sm:
fmt_pkg = m.import_("fmt")
candidates = ", ".join([str(x) for x in const_names])
sm.return_(
fmt_pkg.Errorf(
as_literal(
str,
f"%q is invalid enum value of ({candidates})"),
this,
))
sm.unnewline()
# func (v <enum>) UnmarshalJSON(b []byte) error {
# ...
# }
with m.method(f"{this} *{go_type}",
"UnmarshalJSON",
f"b []byte",
returns="error"):
strings_pkg = m.import_("strings")
m.stmt(f'*{this} = {go_type}({strings_pkg}.Trim(string(b), `"`))')
m.return_(this.Valid())
definition = Definition(name=go_type, code_module=None)
return definition