Extract FileAdder and all Desc helpers to upb_generator/common

PiperOrigin-RevId: 691208172

upb_generator/common/BUILD

@@ -20,3 +20,24 @@ cc_library(
         "@com_google_absl//absl/strings:string_view",
     ],
 )
+
+cc_library(
+    name = "cpp_to_upb_def",
+    srcs = ["cpp_to_upb_def.cc"],
+    hdrs = ["cpp_to_upb_def.h"],
+    visibility = [
+        "//src/google/protobuf/compiler/hpb:__subpackages__",
+        "//third_party/kotlin/protobuf/generator/native:__subpackages__",
+    ],
+    deps = [
+        "//:protobuf",
+        "//src/google/protobuf",
+        "//src/google/protobuf:descriptor_upb_c_proto",
+        "//upb:base",
+        "//upb:mem",
+        "//upb:mini_table",
+        "//upb:reflection",
+        "@com_google_absl//absl/container:flat_hash_set",
+        "@com_google_absl//absl/log:absl_check",
+    ],
+)

upb_generator/common/cpp_to_upb_def.cc

@@ -0,0 +1,98 @@
+// Copyright (c) 2024 Google LLC
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+#include "upb_generator/common/cpp_to_upb_def.h"
+
+#include <string>
+
+#include "google/protobuf/descriptor.upb.h"
+#include "absl/log/absl_check.h"
+#include "google/protobuf/descriptor.h"
+#include "upb/base/status.hpp"
+#include "upb/mem/arena.hpp"
+#include "upb/mini_table/field.h"
+#include "upb/reflection/def.hpp"
+
+namespace upb::generator {
+
+using google::protobuf::Descriptor;
+using google::protobuf::EnumDescriptor;
+using google::protobuf::FieldDescriptor;
+using google::protobuf::FileDescriptor;
+
+// Internal helper that takes a filedesc and emits a upb proto;
+// used for defpool tracking and dependency management
+google_protobuf_FileDescriptorProto* ToUpbProto(const FileDescriptor* file,
+                                       upb::Arena* arena) {
+  google::protobuf::FileDescriptorProto proto;
+  file->CopyTo(&proto);
+  std::string serialized_proto = proto.SerializeAsString();
+  google_protobuf_FileDescriptorProto* upb_proto = google_protobuf_FileDescriptorProto_parse(
+      serialized_proto.data(), serialized_proto.size(), arena->ptr());
+  ABSL_CHECK(upb_proto) << "Failed to parse proto";
+  return upb_proto;
+}
+
+void AddFile(const FileDescriptor* file, upb::DefPool* pool) {
+  // Avoid adding the same file twice.
+  if (pool->FindFileByName(file->name().c_str())) return;
+
+  // Like a google::protobuf::DescriptorPool, a upb::DefPool requires that all
+  // dependencies are added first.
+  for (int i = 0; i < file->dependency_count(); i++) {
+    AddFile(file->dependency(i), pool);
+  }
+
+  upb::Arena tmp_arena;
+  upb::Status status;
+  ABSL_CHECK(pool->AddFile(ToUpbProto(file, &tmp_arena), &status))
+      << status.error_message();
+}
+
+upb::MessageDefPtr FindMessageDef(upb::DefPool& pool,
+                                  const Descriptor* descriptor) {
+  const std::string& name = descriptor->full_name();
+  upb::MessageDefPtr message_def = pool.FindMessageByName(name.c_str());
+  ABSL_CHECK(message_def) << "No message named " << name;
+  return message_def;
+}
+
+upb::EnumDefPtr FindEnumDef(upb::DefPool& pool,
+                            const EnumDescriptor* enum_descriptor) {
+  const std::string& name = enum_descriptor->full_name();
+  upb::EnumDefPtr enum_def = pool.FindEnumByName(name.c_str());
+  ABSL_CHECK(enum_def) << "No enum named " << name;
+  return enum_def;
+}
+
+upb::FieldDefPtr FindBaseFieldDef(upb::DefPool& pool,
+                                  const FieldDescriptor* field) {
+  ABSL_CHECK(!field->is_extension());
+  upb::MessageDefPtr message_def =
+      FindMessageDef(pool, field->containing_type());
+  upb::FieldDefPtr field_def = message_def.FindFieldByNumber(field->number());
+  ABSL_CHECK(field_def) << "No field with number " << field->number()
+                        << " in message " << message_def.full_name();
+  return field_def;
+}
+
+upb::FieldDefPtr FindExtensionDef(upb::DefPool& pool,
+                                  const FieldDescriptor* field) {
+  ABSL_CHECK(field->is_extension());
+  return pool.FindExtensionByName(field->full_name().c_str());
+}
+
+const FieldDescriptor* FindFieldDescriptor(
+    const Descriptor* message, const upb_MiniTableField* field_def) {
+  int field_number = upb_MiniTableField_Number(field_def);
+  const FieldDescriptor* field = message->FindFieldByNumber(field_number);
+  ABSL_CHECK(field) << "No field in message " << message->full_name()
+                    << " with number " << field_number;
+  return field;
+}
+
+}  // namespace upb::generator

upb_generator/common/cpp_to_upb_def.h

@@ -0,0 +1,58 @@
+// Copyright (c) 2024 Google LLC
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+#ifndef THIRD_PARTY_UPB_UPB_GENERATOR_COMMON_DESC_HELPERS_H_
+#define THIRD_PARTY_UPB_UPB_GENERATOR_COMMON_DESC_HELPERS_H_
+
+#include "google/protobuf/descriptor.pb.h"
+#include "google/protobuf/descriptor.upb.h"
+#include "google/protobuf/descriptor.h"
+#include "upb/mem/arena.hpp"
+#include "upb/mini_table/field.h"
+#include "upb/reflection/def.hpp"
+
+namespace upb::generator {
+
+using google::protobuf::Descriptor;
+using google::protobuf::EnumDescriptor;
+using google::protobuf::FieldDescriptor;
+using google::protobuf::FileDescriptor;
+
+// Add a filedesc to defpool, and all its dependencies.
+void AddFile(const FileDescriptor* file, upb::DefPool* pool);
+
+// Given a Descriptor, returns a MessageDefPtr.
+// This will fail if the message is not in the defpool.
+// Files can be added to the defpool using AddFile.
+upb::MessageDefPtr FindMessageDef(upb::DefPool& pool,
+                                  const Descriptor* descriptor);
+
+// Given an EnumDescriptor, returns an EnumDefPtr.
+// This will fail if the enum is not in the defpool.
+upb::EnumDefPtr FindEnumDef(upb::DefPool& pool,
+                            const EnumDescriptor* enum_descriptor);
+
+// Given a FieldDescriptor, returns a FieldDefPtr.
+// This will fail if the field is not in the defpool.
+// This is for non-extension fields. For extensions, use FindExtensionDef.
+upb::FieldDefPtr FindBaseFieldDef(upb::DefPool& pool,
+                                  const FieldDescriptor* field);
+
+// Given a FieldDescriptor, returns a FieldDefPtr.
+// This will fail if the field is not in the defpool.
+// This is solely for extension fields.
+upb::FieldDefPtr FindExtensionDef(upb::DefPool& pool,
+                                  const FieldDescriptor* field);
+
+// Looks up a FieldDescriptor from a upb_MiniTableField.
+// This will fail if the field is not in the message.
+const FieldDescriptor* FindFieldDescriptor(const Descriptor* message,
+                                           const upb_MiniTableField* field_def);
+
+}  // namespace upb::generator
+
+#endif  // THIRD_PARTY_UPB_UPB_GENERATOR_COMMON_DESC_HELPERS_H_