[v2,04/11] qapi: golang: Generate qapi's alternate types in Go

Message ID	20231016152704.221611-5-victortoso@redhat.com
State	New
Headers	show Return-Path: <qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org> From: Victor Toso <victortoso@redhat.com> To: qemu-devel@nongnu.org Cc: Markus Armbruster <armbru@redhat.com>, John Snow <jsnow@redhat.com>, =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= <berrange@redhat.com>, Andrea Bolognani <abologna@redhat.com> Subject: [PATCH v2 04/11] qapi: golang: Generate qapi's alternate types in Go Date: Mon, 16 Oct 2023 17:26:57 +0200 Message-ID: <20231016152704.221611-5-victortoso@redhat.com> In-Reply-To: <20231016152704.221611-1-victortoso@redhat.com> References: <20231016152704.221611-1-victortoso@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=victortoso@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action Precedence: list Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org
Series	qapi-go: add generator for Golang interface \| expand [v2,00/11] qapi-go: add generator for Golang interface [v2,01/11] qapi: re-establish linting baseline [v2,02/11] scripts: qapi: black format main.py [v2,03/11] qapi: golang: Generate qapi's enum types in Go [v2,04/11] qapi: golang: Generate qapi's alternate types in Go [v2,05/11] qapi: golang: Generate qapi's struct types in Go [v2,06/11] qapi: golang: structs: Address 'null' members [v2,07/11] qapi: golang: Generate qapi's union types in Go [v2,08/11] qapi: golang: Generate qapi's event types in Go [v2,09/11] qapi: golang: Generate qapi's command types in Go [v2,10/11] qapi: golang: Add CommandResult type to Go [v2,11/11] docs: add notes on Golang code generator

diff --git a/scripts/qapi/golang.py b/scripts/qapi/golang.py index dc12be7b03..3f6692df4b 100644 --- a/scripts/qapi/golang.py +++ b/scripts/qapi/golang.py @@ -13,10 +13,11 @@ from __future__ import annotations import os -from typing import List, Optional +from typing import List, Optional, Tuple from .schema import ( QAPISchema, + QAPISchemaAlternateType, QAPISchemaEnumMember, QAPISchemaFeature, QAPISchemaIfCond, @@ -37,6 +38,77 @@ ) """ +TEMPLATE_HELPER = """ +// Creates a decoder that errors on unknown Fields +// Returns nil if successfully decoded @from payload to @into type +// Returns error if failed to decode @from payload to @into type +func StrictDecode(into interface{}, from []byte) error { +\tdec := json.NewDecoder(strings.NewReader(string(from))) +\tdec.DisallowUnknownFields() + +\tif err := dec.Decode(into); err != nil { +\t\treturn err +\t} +\treturn nil +} +""" + +TEMPLATE_ALTERNATE = """ +// Only implemented on Alternate types that can take JSON NULL as value. +// +// This is a helper for the marshalling code. It should return true only when +// the Alternate is empty (no members are set), otherwise it returns false and +// the member set to be Marshalled. +type AbsentAlternate interface { +\tToAnyOrAbsent() (any, bool) +} +""" + +TEMPLATE_ALTERNATE_NULLABLE_CHECK = """ +\t\t}} else if s.{var_name} != nil {{ +\t\t\treturn *s.{var_name}, false""" + +TEMPLATE_ALTERNATE_MARSHAL_CHECK = """ +\tif s.{var_name} != nil {{ +\t\treturn json.Marshal(s.{var_name}) +\t}} else """ + +TEMPLATE_ALTERNATE_UNMARSHAL_CHECK = """ +\t// Check for {var_type} +\t{{ +\t\ts.{var_name} = new({var_type}) +\t\tif err := StrictDecode(s.{var_name}, data); err == nil {{ +\t\t\treturn nil +\t\t}} +\t\ts.{var_name} = nil +\t}} +""" + +TEMPLATE_ALTERNATE_NULLABLE = """ +func (s *{name}) ToAnyOrAbsent() (any, bool) {{ +\tif s != nil {{ +\t\tif s.IsNull {{ +\t\t\treturn nil, false +{absent_check_fields} +\t\t}} +\t}} + +\treturn nil, true +}} +""" + +TEMPLATE_ALTERNATE_METHODS = """ +func (s {name}) MarshalJSON() ([]byte, error) {{ +\t{marshal_check_fields} +\treturn {marshal_return_default} +}} + +func (s *{name}) UnmarshalJSON(data []byte) error {{ +{unmarshal_check_fields} +\treturn fmt.Errorf("Can't convert to {name}: %s", string(data)) +}} +""" + def gen_golang(schema: QAPISchema, output_dir: str, prefix: str) -> None: vis = QAPISchemaGenGolangVisitor(prefix) @@ -44,10 +116,191 @@ def gen_golang(schema: QAPISchema, output_dir: str, prefix: str) -> None: vis.write(output_dir) +def qapi_to_field_name(name: str) -> str: + return name.title().replace("_", "").replace("-", "") + + def qapi_to_field_name_enum(name: str) -> str: return name.title().replace("-", "") +def qapi_schema_type_to_go_type(qapitype: str) -> str: + schema_types_to_go = { + "str": "string", + "null": "nil", + "bool": "bool", + "number": "float64", + "size": "uint64", + "int": "int64", + "int8": "int8", + "int16": "int16", + "int32": "int32", + "int64": "int64", + "uint8": "uint8", + "uint16": "uint16", + "uint32": "uint32", + "uint64": "uint64", + "any": "any", + "QType": "QType", + } + + prefix = "" + if qapitype.endswith("List"): + prefix = "[]" + qapitype = qapitype[:-4] + + qapitype = schema_types_to_go.get(qapitype, qapitype) + return prefix + qapitype + + +def qapi_field_to_go_field( + member_name: str, type_name: str +) -> Tuple[str, str, str]: + # Nothing to generate on null types. We update some + # variables to handle json-null on marshalling methods. + if type_name == "null": + return "IsNull", "bool", "" + + # This function is called on Alternate, so fields should be ptrs + return ( + qapi_to_field_name(member_name), + qapi_schema_type_to_go_type(type_name), + "*", + ) + + +# Helper function for boxed or self contained structures. +def generate_struct_type( + type_name, args: List[dict[str:str]] = None, ident: int = 0 +) -> str: + members = "{}" + base_ident = "\t" * ident + if args is not None: + # Most of the logic below is to mimic the gofmt tool. + # We calculate spaces between member and type and between + # the type and tag. Note that gofmt considers comments as + # divider between ident blocks. + maxname, maxtype = 0, 0 + blocks: tuple(int, int) = [] + for arg in args: + if "comment" in arg: + blocks.append((maxname, maxtype)) + maxname, maxtype = 0, 0 + continue + + if "type" not in arg: + continue + + maxname = max(maxname, len(arg["name"])) + maxtype = max(maxtype, len(arg["type"])) + + blocks.append((maxname, maxtype)) + block = 0 + + maxname, maxtype = blocks[0] + members = " {\n" + for arg in args: + if "comment" in arg: + block += 1 + maxname, maxtype = blocks[block] + members += f"""\t// {arg["comment"]}\n""" + continue + + name2type = "" + if "type" in arg: + name2type = " " * (maxname - len(arg["name"]) + 1) + type2tag = "" + if "tag" in arg: + type2tag = " " * (maxtype - len(arg["type"]) + 1) + + fident = "\t" * (ident + 1) + gotype = "" if "type" not in arg else arg["type"] + tag = "" if "tag" not in arg else arg["tag"] + name = arg["name"] + members += ( + f"""{fident}{name}{name2type}{gotype}{type2tag}{tag}\n""" + ) + members += f"{base_ident}}}\n" + + with_type = f"\n{base_ident}type {type_name}" if len(type_name) > 0 else "" + return f"""{with_type} struct{members}""" + + +def generate_template_alternate( + self: QAPISchemaGenGolangVisitor, + name: str, + variants: Optional[QAPISchemaVariants], +) -> str: + absent_check_fields = "" + args: List[dict[str:str]] = [] + # to avoid having to check accept_null_types + nullable = False + if name in self.accept_null_types: + # In QEMU QAPI schema, only StrOrNull and BlockdevRefOrNull. + nullable = True + marshal_return_default = """[]byte("{}"), nil""" + marshal_check_fields = """if s.IsNull { +\t\treturn []byte("null"), nil +\t} else """ + unmarshal_check_fields = """ +\t// Check for json-null first +\tif string(data) == "null" { +\t\ts.IsNull = true +\t\treturn nil +\t}""" + else: + marshal_return_default = f'nil, errors.New("{name} has empty fields")' + marshal_check_fields = "" + unmarshal_check_fields = f""" +\t// Check for json-null first +\tif string(data) == "null" {{ +\t\treturn errors.New(`null not supported for {name}`) +\t}}""" + + if variants: + for var in variants.variants: + var_name, var_type, isptr = qapi_field_to_go_field( + var.name, var.type.name + ) + args.append( + { + "name": f"{var_name}", + "type": f"{isptr}{var_type}", + } + ) + + # Null is special, handled first + if var.type.name == "null": + assert nullable + continue + + if nullable: + absent_check_fields += ( + TEMPLATE_ALTERNATE_NULLABLE_CHECK.format(var_name=var_name) + ) + marshal_check_fields += TEMPLATE_ALTERNATE_MARSHAL_CHECK[ + 2: + ].format(var_name=var_name) + unmarshal_check_fields += ( + TEMPLATE_ALTERNATE_UNMARSHAL_CHECK.format( + var_name=var_name, var_type=var_type + ) + ) + + content = generate_struct_type(name, args) + if nullable: + content += TEMPLATE_ALTERNATE_NULLABLE.format( + name=name, absent_check_fields=absent_check_fields + ) + content += TEMPLATE_ALTERNATE_METHODS.format( + name=name, + marshal_check_fields=marshal_check_fields[:-6], + marshal_return_default=marshal_return_default, + unmarshal_check_fields=unmarshal_check_fields[1:], + ) + return content + + def generate_content_from_dict(data: dict[str, str]) -> str: content = "" @@ -61,22 +314,60 @@ class QAPISchemaGenGolangVisitor(QAPISchemaVisitor): # pylint: disable=too-many-arguments def __init__(self, _: str): super().__init__() - types = ("enum",) + types = ( + "alternate", + "enum", + "helper", + ) self.target = dict.fromkeys(types, "") self.schema: QAPISchema self.golang_package_name = "qapi" self.enums: dict[str, str] = {} + self.alternates: dict[str, str] = {} + self.accept_null_types = [] def visit_begin(self, schema: QAPISchema) -> None: self.schema = schema + # We need to be aware of any types that accept JSON NULL + for name, entity in self.schema._entity_dict.items(): + if not isinstance(entity, QAPISchemaAlternateType): + # Assume that only Alternate types accept JSON NULL + continue + + for var in entity.variants.variants: + if var.type.name == "null": + self.accept_null_types.append(name) + break + # Every Go file needs to reference its package name + # and most have some imports too. for target in self.target: self.target[target] = f"package {self.golang_package_name}\n" + if target == "helper": + imports = """\nimport ( +\t"encoding/json" +\t"strings" +) +""" + else: + imports = """\nimport ( +\t"encoding/json" +\t"errors" +\t"fmt" +) +""" + if target != "enum": + self.target[target] += imports + + self.target["helper"] += TEMPLATE_HELPER + self.target["alternate"] += TEMPLATE_ALTERNATE + def visit_end(self) -> None: del self.schema self.target["enum"] += generate_content_from_dict(self.enums) + self.target["alternate"] += generate_content_from_dict(self.alternates) def visit_object_type( self, @@ -98,7 +389,11 @@ def visit_alternate_type( features: List[QAPISchemaFeature], variants: QAPISchemaVariants, ) -> None: - pass + assert name not in self.alternates + + self.alternates[name] = generate_template_alternate( + self, name, variants + ) def visit_enum_type( self,

[v2,04/11] qapi: golang: Generate qapi's alternate types in Go

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