|  | // Protocol Buffers - Google's data interchange format | 
|  | // Copyright 2023 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/reflection/internal/def_pool.h" | 
|  |  | 
|  | #include "upb/base/status.h" | 
|  | #include "upb/hash/int_table.h" | 
|  | #include "upb/hash/str_table.h" | 
|  | #include "upb/mem/alloc.h" | 
|  | #include "upb/mem/arena.h" | 
|  | #include "upb/reflection/def_type.h" | 
|  | #include "upb/reflection/file_def.h" | 
|  | #include "upb/reflection/internal/def_builder.h" | 
|  | #include "upb/reflection/internal/enum_def.h" | 
|  | #include "upb/reflection/internal/enum_value_def.h" | 
|  | #include "upb/reflection/internal/field_def.h" | 
|  | #include "upb/reflection/internal/file_def.h" | 
|  | #include "upb/reflection/internal/message_def.h" | 
|  | #include "upb/reflection/internal/service_def.h" | 
|  | #include "upb/reflection/internal/upb_edition_defaults.h" | 
|  |  | 
|  | // Must be last. | 
|  | #include "upb/port/def.inc" | 
|  |  | 
|  | struct upb_DefPool { | 
|  | upb_Arena* arena; | 
|  | upb_strtable syms;   // full_name -> packed def ptr | 
|  | upb_strtable files;  // file_name -> (upb_FileDef*) | 
|  | upb_inttable exts;   // (upb_MiniTableExtension*) -> (upb_FieldDef*) | 
|  | upb_ExtensionRegistry* extreg; | 
|  | const UPB_DESC(FeatureSetDefaults) * feature_set_defaults; | 
|  | upb_MiniTablePlatform platform; | 
|  | void* scratch_data; | 
|  | size_t scratch_size; | 
|  | size_t bytes_loaded; | 
|  | }; | 
|  |  | 
|  | void upb_DefPool_Free(upb_DefPool* s) { | 
|  | upb_Arena_Free(s->arena); | 
|  | upb_gfree(s->scratch_data); | 
|  | upb_gfree(s); | 
|  | } | 
|  |  | 
|  | static const char serialized_defaults[] = UPB_INTERNAL_UPB_EDITION_DEFAULTS; | 
|  |  | 
|  | upb_DefPool* upb_DefPool_New(void) { | 
|  | upb_DefPool* s = upb_gmalloc(sizeof(*s)); | 
|  | if (!s) return NULL; | 
|  |  | 
|  | s->arena = upb_Arena_New(); | 
|  | s->bytes_loaded = 0; | 
|  |  | 
|  | s->scratch_size = 240; | 
|  | s->scratch_data = upb_gmalloc(s->scratch_size); | 
|  | if (!s->scratch_data) goto err; | 
|  |  | 
|  | if (!upb_strtable_init(&s->syms, 32, s->arena)) goto err; | 
|  | if (!upb_strtable_init(&s->files, 4, s->arena)) goto err; | 
|  | if (!upb_inttable_init(&s->exts, s->arena)) goto err; | 
|  |  | 
|  | s->extreg = upb_ExtensionRegistry_New(s->arena); | 
|  | if (!s->extreg) goto err; | 
|  |  | 
|  | s->platform = kUpb_MiniTablePlatform_Native; | 
|  |  | 
|  | upb_Status status; | 
|  | if (!upb_DefPool_SetFeatureSetDefaults( | 
|  | s, serialized_defaults, sizeof(serialized_defaults) - 1, &status)) { | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | if (!s->feature_set_defaults) goto err; | 
|  |  | 
|  | return s; | 
|  |  | 
|  | err: | 
|  | upb_DefPool_Free(s); | 
|  | return NULL; | 
|  | } | 
|  |  | 
|  | const UPB_DESC(FeatureSetDefaults) * | 
|  | upb_DefPool_FeatureSetDefaults(const upb_DefPool* s) { | 
|  | return s->feature_set_defaults; | 
|  | } | 
|  |  | 
|  | bool upb_DefPool_SetFeatureSetDefaults(upb_DefPool* s, | 
|  | const char* serialized_defaults, | 
|  | size_t serialized_len, | 
|  | upb_Status* status) { | 
|  | const UPB_DESC(FeatureSetDefaults)* defaults = UPB_DESC( | 
|  | FeatureSetDefaults_parse)(serialized_defaults, serialized_len, s->arena); | 
|  | if (!defaults) { | 
|  | upb_Status_SetErrorFormat(status, "Failed to parse defaults"); | 
|  | return false; | 
|  | } | 
|  | if (upb_strtable_count(&s->files) > 0) { | 
|  | upb_Status_SetErrorFormat(status, | 
|  | "Feature set defaults can't be changed once the " | 
|  | "pool has started building"); | 
|  | return false; | 
|  | } | 
|  | int min_edition = UPB_DESC(FeatureSetDefaults_minimum_edition(defaults)); | 
|  | int max_edition = UPB_DESC(FeatureSetDefaults_maximum_edition(defaults)); | 
|  | if (min_edition > max_edition) { | 
|  | upb_Status_SetErrorFormat(status, "Invalid edition range %s to %s", | 
|  | upb_FileDef_EditionName(min_edition), | 
|  | upb_FileDef_EditionName(max_edition)); | 
|  | return false; | 
|  | } | 
|  | size_t size; | 
|  | const UPB_DESC( | 
|  | FeatureSetDefaults_FeatureSetEditionDefault)* const* default_list = | 
|  | UPB_DESC(FeatureSetDefaults_defaults(defaults, &size)); | 
|  | int prev_edition = UPB_DESC(EDITION_UNKNOWN); | 
|  | for (size_t i = 0; i < size; ++i) { | 
|  | int edition = UPB_DESC( | 
|  | FeatureSetDefaults_FeatureSetEditionDefault_edition(default_list[i])); | 
|  | if (edition == UPB_DESC(EDITION_UNKNOWN)) { | 
|  | upb_Status_SetErrorFormat(status, "Invalid edition UNKNOWN specified"); | 
|  | return false; | 
|  | } | 
|  | if (edition <= prev_edition) { | 
|  | upb_Status_SetErrorFormat(status, | 
|  | "Feature set defaults are not strictly " | 
|  | "increasing, %s is greater than or equal to %s", | 
|  | upb_FileDef_EditionName(prev_edition), | 
|  | upb_FileDef_EditionName(edition)); | 
|  | return false; | 
|  | } | 
|  | prev_edition = edition; | 
|  | } | 
|  |  | 
|  | // Copy the defaults into the pool. | 
|  | s->feature_set_defaults = defaults; | 
|  | return true; | 
|  | } | 
|  |  | 
|  | bool _upb_DefPool_InsertExt(upb_DefPool* s, const upb_MiniTableExtension* ext, | 
|  | const upb_FieldDef* f) { | 
|  | return upb_inttable_insert(&s->exts, (uintptr_t)ext, upb_value_constptr(f), | 
|  | s->arena); | 
|  | } | 
|  |  | 
|  | bool _upb_DefPool_InsertSym(upb_DefPool* s, upb_StringView sym, upb_value v, | 
|  | upb_Status* status) { | 
|  | // TODO: table should support an operation "tryinsert" to avoid the double | 
|  | // lookup. | 
|  | if (upb_strtable_lookup2(&s->syms, sym.data, sym.size, NULL)) { | 
|  | upb_Status_SetErrorFormat(status, "duplicate symbol '%s'", sym.data); | 
|  | return false; | 
|  | } | 
|  | if (!upb_strtable_insert(&s->syms, sym.data, sym.size, v, s->arena)) { | 
|  | upb_Status_SetErrorMessage(status, "out of memory"); | 
|  | return false; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static const void* _upb_DefPool_Unpack(const upb_DefPool* s, const char* sym, | 
|  | size_t size, upb_deftype_t type) { | 
|  | upb_value v; | 
|  | return upb_strtable_lookup2(&s->syms, sym, size, &v) | 
|  | ? _upb_DefType_Unpack(v, type) | 
|  | : NULL; | 
|  | } | 
|  |  | 
|  | bool _upb_DefPool_LookupSym(const upb_DefPool* s, const char* sym, size_t size, | 
|  | upb_value* v) { | 
|  | return upb_strtable_lookup2(&s->syms, sym, size, v); | 
|  | } | 
|  |  | 
|  | upb_ExtensionRegistry* _upb_DefPool_ExtReg(const upb_DefPool* s) { | 
|  | return s->extreg; | 
|  | } | 
|  |  | 
|  | void** _upb_DefPool_ScratchData(const upb_DefPool* s) { | 
|  | return (void**)&s->scratch_data; | 
|  | } | 
|  |  | 
|  | size_t* _upb_DefPool_ScratchSize(const upb_DefPool* s) { | 
|  | return (size_t*)&s->scratch_size; | 
|  | } | 
|  |  | 
|  | void _upb_DefPool_SetPlatform(upb_DefPool* s, upb_MiniTablePlatform platform) { | 
|  | assert(upb_strtable_count(&s->files) == 0); | 
|  | s->platform = platform; | 
|  | } | 
|  |  | 
|  | const upb_MessageDef* upb_DefPool_FindMessageByName(const upb_DefPool* s, | 
|  | const char* sym) { | 
|  | return _upb_DefPool_Unpack(s, sym, strlen(sym), UPB_DEFTYPE_MSG); | 
|  | } | 
|  |  | 
|  | const upb_MessageDef* upb_DefPool_FindMessageByNameWithSize( | 
|  | const upb_DefPool* s, const char* sym, size_t len) { | 
|  | return _upb_DefPool_Unpack(s, sym, len, UPB_DEFTYPE_MSG); | 
|  | } | 
|  |  | 
|  | const upb_EnumDef* upb_DefPool_FindEnumByName(const upb_DefPool* s, | 
|  | const char* sym) { | 
|  | return _upb_DefPool_Unpack(s, sym, strlen(sym), UPB_DEFTYPE_ENUM); | 
|  | } | 
|  |  | 
|  | const upb_EnumValueDef* upb_DefPool_FindEnumByNameval(const upb_DefPool* s, | 
|  | const char* sym) { | 
|  | return _upb_DefPool_Unpack(s, sym, strlen(sym), UPB_DEFTYPE_ENUMVAL); | 
|  | } | 
|  |  | 
|  | const upb_FileDef* upb_DefPool_FindFileByName(const upb_DefPool* s, | 
|  | const char* name) { | 
|  | upb_value v; | 
|  | return upb_strtable_lookup(&s->files, name, &v) ? upb_value_getconstptr(v) | 
|  | : NULL; | 
|  | } | 
|  |  | 
|  | const upb_FileDef* upb_DefPool_FindFileByNameWithSize(const upb_DefPool* s, | 
|  | const char* name, | 
|  | size_t len) { | 
|  | upb_value v; | 
|  | return upb_strtable_lookup2(&s->files, name, len, &v) | 
|  | ? upb_value_getconstptr(v) | 
|  | : NULL; | 
|  | } | 
|  |  | 
|  | const upb_FieldDef* upb_DefPool_FindExtensionByNameWithSize( | 
|  | const upb_DefPool* s, const char* name, size_t size) { | 
|  | upb_value v; | 
|  | if (!upb_strtable_lookup2(&s->syms, name, size, &v)) return NULL; | 
|  |  | 
|  | switch (_upb_DefType_Type(v)) { | 
|  | case UPB_DEFTYPE_FIELD: | 
|  | return _upb_DefType_Unpack(v, UPB_DEFTYPE_FIELD); | 
|  | case UPB_DEFTYPE_MSG: { | 
|  | const upb_MessageDef* m = _upb_DefType_Unpack(v, UPB_DEFTYPE_MSG); | 
|  | return _upb_MessageDef_InMessageSet(m) | 
|  | ? upb_MessageDef_NestedExtension(m, 0) | 
|  | : NULL; | 
|  | } | 
|  | default: | 
|  | break; | 
|  | } | 
|  |  | 
|  | return NULL; | 
|  | } | 
|  |  | 
|  | const upb_FieldDef* upb_DefPool_FindExtensionByName(const upb_DefPool* s, | 
|  | const char* sym) { | 
|  | return upb_DefPool_FindExtensionByNameWithSize(s, sym, strlen(sym)); | 
|  | } | 
|  |  | 
|  | const upb_ServiceDef* upb_DefPool_FindServiceByName(const upb_DefPool* s, | 
|  | const char* name) { | 
|  | return _upb_DefPool_Unpack(s, name, strlen(name), UPB_DEFTYPE_SERVICE); | 
|  | } | 
|  |  | 
|  | const upb_ServiceDef* upb_DefPool_FindServiceByNameWithSize( | 
|  | const upb_DefPool* s, const char* name, size_t size) { | 
|  | return _upb_DefPool_Unpack(s, name, size, UPB_DEFTYPE_SERVICE); | 
|  | } | 
|  |  | 
|  | const upb_FileDef* upb_DefPool_FindFileContainingSymbol(const upb_DefPool* s, | 
|  | const char* name) { | 
|  | upb_value v; | 
|  | // TODO: non-extension fields and oneofs. | 
|  | if (upb_strtable_lookup(&s->syms, name, &v)) { | 
|  | switch (_upb_DefType_Type(v)) { | 
|  | case UPB_DEFTYPE_EXT: { | 
|  | const upb_FieldDef* f = _upb_DefType_Unpack(v, UPB_DEFTYPE_EXT); | 
|  | return upb_FieldDef_File(f); | 
|  | } | 
|  | case UPB_DEFTYPE_MSG: { | 
|  | const upb_MessageDef* m = _upb_DefType_Unpack(v, UPB_DEFTYPE_MSG); | 
|  | return upb_MessageDef_File(m); | 
|  | } | 
|  | case UPB_DEFTYPE_ENUM: { | 
|  | const upb_EnumDef* e = _upb_DefType_Unpack(v, UPB_DEFTYPE_ENUM); | 
|  | return upb_EnumDef_File(e); | 
|  | } | 
|  | case UPB_DEFTYPE_ENUMVAL: { | 
|  | const upb_EnumValueDef* ev = | 
|  | _upb_DefType_Unpack(v, UPB_DEFTYPE_ENUMVAL); | 
|  | return upb_EnumDef_File(upb_EnumValueDef_Enum(ev)); | 
|  | } | 
|  | case UPB_DEFTYPE_SERVICE: { | 
|  | const upb_ServiceDef* service = | 
|  | _upb_DefType_Unpack(v, UPB_DEFTYPE_SERVICE); | 
|  | return upb_ServiceDef_File(service); | 
|  | } | 
|  | default: | 
|  | UPB_UNREACHABLE(); | 
|  | } | 
|  | } | 
|  |  | 
|  | const char* last_dot = strrchr(name, '.'); | 
|  | if (last_dot) { | 
|  | const upb_MessageDef* parent = | 
|  | upb_DefPool_FindMessageByNameWithSize(s, name, last_dot - name); | 
|  | if (parent) { | 
|  | const char* shortname = last_dot + 1; | 
|  | if (upb_MessageDef_FindByNameWithSize(parent, shortname, | 
|  | strlen(shortname), NULL, NULL)) { | 
|  | return upb_MessageDef_File(parent); | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | return NULL; | 
|  | } | 
|  |  | 
|  | static void remove_filedef(upb_DefPool* s, upb_FileDef* file) { | 
|  | intptr_t iter = UPB_INTTABLE_BEGIN; | 
|  | upb_StringView key; | 
|  | upb_value val; | 
|  | while (upb_strtable_next2(&s->syms, &key, &val, &iter)) { | 
|  | const upb_FileDef* f; | 
|  | switch (_upb_DefType_Type(val)) { | 
|  | case UPB_DEFTYPE_EXT: | 
|  | f = upb_FieldDef_File(_upb_DefType_Unpack(val, UPB_DEFTYPE_EXT)); | 
|  | break; | 
|  | case UPB_DEFTYPE_MSG: | 
|  | f = upb_MessageDef_File(_upb_DefType_Unpack(val, UPB_DEFTYPE_MSG)); | 
|  | break; | 
|  | case UPB_DEFTYPE_ENUM: | 
|  | f = upb_EnumDef_File(_upb_DefType_Unpack(val, UPB_DEFTYPE_ENUM)); | 
|  | break; | 
|  | case UPB_DEFTYPE_ENUMVAL: | 
|  | f = upb_EnumDef_File(upb_EnumValueDef_Enum( | 
|  | _upb_DefType_Unpack(val, UPB_DEFTYPE_ENUMVAL))); | 
|  | break; | 
|  | case UPB_DEFTYPE_SERVICE: | 
|  | f = upb_ServiceDef_File(_upb_DefType_Unpack(val, UPB_DEFTYPE_SERVICE)); | 
|  | break; | 
|  | default: | 
|  | UPB_UNREACHABLE(); | 
|  | } | 
|  |  | 
|  | if (f == file) upb_strtable_removeiter(&s->syms, &iter); | 
|  | } | 
|  | } | 
|  |  | 
|  | static const upb_FileDef* upb_DefBuilder_AddFileToPool( | 
|  | upb_DefBuilder* const builder, upb_DefPool* const s, | 
|  | const UPB_DESC(FileDescriptorProto) * const file_proto, | 
|  | const upb_StringView name, upb_Status* const status) { | 
|  | if (UPB_SETJMP(builder->err) != 0) { | 
|  | UPB_ASSERT(!upb_Status_IsOk(status)); | 
|  | if (builder->file) { | 
|  | remove_filedef(s, builder->file); | 
|  | builder->file = NULL; | 
|  | } | 
|  | } else if (!builder->arena || !builder->tmp_arena || | 
|  | !upb_strtable_init(&builder->feature_cache, 16, | 
|  | builder->tmp_arena) || | 
|  | !(builder->legacy_features = | 
|  | UPB_DESC(FeatureSet_new)(builder->tmp_arena))) { | 
|  | _upb_DefBuilder_OomErr(builder); | 
|  | } else { | 
|  | _upb_FileDef_Create(builder, file_proto); | 
|  | upb_strtable_insert(&s->files, name.data, name.size, | 
|  | upb_value_constptr(builder->file), builder->arena); | 
|  | UPB_ASSERT(upb_Status_IsOk(status)); | 
|  | upb_Arena_Fuse(s->arena, builder->arena); | 
|  | } | 
|  |  | 
|  | if (builder->arena) upb_Arena_Free(builder->arena); | 
|  | if (builder->tmp_arena) upb_Arena_Free(builder->tmp_arena); | 
|  | return builder->file; | 
|  | } | 
|  |  | 
|  | static const upb_FileDef* _upb_DefPool_AddFile( | 
|  | upb_DefPool* s, const UPB_DESC(FileDescriptorProto) * file_proto, | 
|  | const upb_MiniTableFile* layout, upb_Status* status) { | 
|  | const upb_StringView name = UPB_DESC(FileDescriptorProto_name)(file_proto); | 
|  |  | 
|  | // Determine whether we already know about this file. | 
|  | { | 
|  | upb_value v; | 
|  | if (upb_strtable_lookup2(&s->files, name.data, name.size, &v)) { | 
|  | upb_Status_SetErrorFormat(status, | 
|  | "duplicate file name " UPB_STRINGVIEW_FORMAT, | 
|  | UPB_STRINGVIEW_ARGS(name)); | 
|  | return NULL; | 
|  | } | 
|  | } | 
|  |  | 
|  | upb_DefBuilder ctx = { | 
|  | .symtab = s, | 
|  | .tmp_buf = NULL, | 
|  | .tmp_buf_size = 0, | 
|  | .layout = layout, | 
|  | .platform = s->platform, | 
|  | .msg_count = 0, | 
|  | .enum_count = 0, | 
|  | .ext_count = 0, | 
|  | .status = status, | 
|  | .file = NULL, | 
|  | .arena = upb_Arena_New(), | 
|  | .tmp_arena = upb_Arena_New(), | 
|  | }; | 
|  |  | 
|  | return upb_DefBuilder_AddFileToPool(&ctx, s, file_proto, name, status); | 
|  | } | 
|  |  | 
|  | const upb_FileDef* upb_DefPool_AddFile(upb_DefPool* s, | 
|  | const UPB_DESC(FileDescriptorProto) * | 
|  | file_proto, | 
|  | upb_Status* status) { | 
|  | return _upb_DefPool_AddFile(s, file_proto, NULL, status); | 
|  | } | 
|  |  | 
|  | bool _upb_DefPool_LoadDefInitEx(upb_DefPool* s, const _upb_DefPool_Init* init, | 
|  | bool rebuild_minitable) { | 
|  | /* Since this function should never fail (it would indicate a bug in upb) we | 
|  | * print errors to stderr instead of returning error status to the user. */ | 
|  | _upb_DefPool_Init** deps = init->deps; | 
|  | UPB_DESC(FileDescriptorProto) * file; | 
|  | upb_Arena* arena; | 
|  | upb_Status status; | 
|  |  | 
|  | upb_Status_Clear(&status); | 
|  |  | 
|  | if (upb_DefPool_FindFileByName(s, init->filename)) { | 
|  | return true; | 
|  | } | 
|  |  | 
|  | arena = upb_Arena_New(); | 
|  |  | 
|  | for (; *deps; deps++) { | 
|  | if (!_upb_DefPool_LoadDefInitEx(s, *deps, rebuild_minitable)) goto err; | 
|  | } | 
|  |  | 
|  | file = UPB_DESC(FileDescriptorProto_parse_ex)( | 
|  | init->descriptor.data, init->descriptor.size, NULL, | 
|  | kUpb_DecodeOption_AliasString, arena); | 
|  | s->bytes_loaded += init->descriptor.size; | 
|  |  | 
|  | if (!file) { | 
|  | upb_Status_SetErrorFormat( | 
|  | &status, | 
|  | "Failed to parse compiled-in descriptor for file '%s'. This should " | 
|  | "never happen.", | 
|  | init->filename); | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | const upb_MiniTableFile* mt = rebuild_minitable ? NULL : init->layout; | 
|  | if (!_upb_DefPool_AddFile(s, file, mt, &status)) { | 
|  | goto err; | 
|  | } | 
|  |  | 
|  | upb_Arena_Free(arena); | 
|  | return true; | 
|  |  | 
|  | err: | 
|  | fprintf(stderr, | 
|  | "Error loading compiled-in descriptor for file '%s' (this should " | 
|  | "never happen): %s\n", | 
|  | init->filename, upb_Status_ErrorMessage(&status)); | 
|  | upb_Arena_Free(arena); | 
|  | return false; | 
|  | } | 
|  |  | 
|  | size_t _upb_DefPool_BytesLoaded(const upb_DefPool* s) { | 
|  | return s->bytes_loaded; | 
|  | } | 
|  |  | 
|  | upb_Arena* _upb_DefPool_Arena(const upb_DefPool* s) { return s->arena; } | 
|  |  | 
|  | const upb_FieldDef* upb_DefPool_FindExtensionByMiniTable( | 
|  | const upb_DefPool* s, const upb_MiniTableExtension* ext) { | 
|  | upb_value v; | 
|  | bool ok = upb_inttable_lookup(&s->exts, (uintptr_t)ext, &v); | 
|  | UPB_ASSERT(ok); | 
|  | return upb_value_getconstptr(v); | 
|  | } | 
|  |  | 
|  | const upb_FieldDef* upb_DefPool_FindExtensionByNumber(const upb_DefPool* s, | 
|  | const upb_MessageDef* m, | 
|  | int32_t fieldnum) { | 
|  | const upb_MiniTable* t = upb_MessageDef_MiniTable(m); | 
|  | const upb_MiniTableExtension* ext = | 
|  | upb_ExtensionRegistry_Lookup(s->extreg, t, fieldnum); | 
|  | return ext ? upb_DefPool_FindExtensionByMiniTable(s, ext) : NULL; | 
|  | } | 
|  |  | 
|  | const upb_ExtensionRegistry* upb_DefPool_ExtensionRegistry( | 
|  | const upb_DefPool* s) { | 
|  | return s->extreg; | 
|  | } | 
|  |  | 
|  | const upb_FieldDef** upb_DefPool_GetAllExtensions(const upb_DefPool* s, | 
|  | const upb_MessageDef* m, | 
|  | size_t* count) { | 
|  | size_t n = 0; | 
|  | intptr_t iter = UPB_INTTABLE_BEGIN; | 
|  | uintptr_t key; | 
|  | upb_value val; | 
|  | // This is O(all exts) instead of O(exts for m).  If we need this to be | 
|  | // efficient we may need to make extreg into a two-level table, or have a | 
|  | // second per-message index. | 
|  | while (upb_inttable_next(&s->exts, &key, &val, &iter)) { | 
|  | const upb_FieldDef* f = upb_value_getconstptr(val); | 
|  | if (upb_FieldDef_ContainingType(f) == m) n++; | 
|  | } | 
|  | const upb_FieldDef** exts = upb_gmalloc(n * sizeof(*exts)); | 
|  | iter = UPB_INTTABLE_BEGIN; | 
|  | size_t i = 0; | 
|  | while (upb_inttable_next(&s->exts, &key, &val, &iter)) { | 
|  | const upb_FieldDef* f = upb_value_getconstptr(val); | 
|  | if (upb_FieldDef_ContainingType(f) == m) exts[i++] = f; | 
|  | } | 
|  | *count = n; | 
|  | return exts; | 
|  | } | 
|  |  | 
|  | bool _upb_DefPool_LoadDefInit(upb_DefPool* s, const _upb_DefPool_Init* init) { | 
|  | return _upb_DefPool_LoadDefInitEx(s, init, false); | 
|  | } |