Add Variant parser and storer.

GitOrigin-RevId: e6b8e46184f67fed50ce96a58a8ba33c17789c57

td/telegram/Photo.h

@@ -53,7 +53,7 @@ struct PhotoSizeSource {
   // for photos, document thumbnails, encrypted thumbnails
   struct Thumbnail {
     Thumbnail() = default;
-    Thumbnail(FileType file_type, int32 thumbnail_type) : thumbnail_type(thumbnail_type) {
+    Thumbnail(FileType file_type, int32 thumbnail_type) : file_type(file_type), thumbnail_type(thumbnail_type) {
     }
 
     FileType file_type;

td/telegram/Photo.hpp

@@ -73,51 +73,12 @@ void PhotoSizeSource::DialogPhoto::parse(ParserT &parser) {
 
 template <class StorerT>
 void PhotoSizeSource::store(StorerT &storer) const {
-  using td::store;
-  auto type = get_type();
-  store(type, storer);
-  switch (type) {
-    case Type::Thumbnail:
-      store(thumbnail(), storer);
-      break;
-    case Type::DialogPhoto:
-      store(dialog_photo(), storer);
-      break;
-    case Type::StickerSetThumbnail:
-      store(sticker_set_thumbnail(), storer);
-      break;
-    case Type::Empty:
-      break;
-  }
+  td::store(variant, storer);
 }
 
 template <class ParserT>
 void PhotoSizeSource::parse(ParserT &parser) {
-  using td::parse;
-  Type type;
-  parse(type, parser);
-  switch (type) {
-    case Type::Thumbnail: {
-      Thumbnail thumbnail;
-      parse(thumbnail, parser);
-      variant = thumbnail;
-      break;
-    }
-    case Type::DialogPhoto: {
-      DialogPhoto dialog_photo;
-      parse(dialog_photo, parser);
-      variant = dialog_photo;
-      break;
-    }
-    case Type::StickerSetThumbnail: {
-      StickerSetThumbnail sticker_set_thumbnail;
-      parse(sticker_set_thumbnail, parser);
-      variant = sticker_set_thumbnail;
-      break;
-    }
-    case Type::Empty:
-      break;
-  }
+  td::parse(variant, parser);
 }
 
 template <class StorerT>

td/telegram/files/FileLocation.h

@@ -744,6 +744,8 @@ struct PartialLocalFileLocationPtr {
 
   template <class StorerT>
   void store(StorerT &storer) const;
+  template <class ParserT>
+  void parse(ParserT &parser);
 };
 
 inline bool operator==(const PartialLocalFileLocationPtr &lhs, const PartialLocalFileLocationPtr &rhs) {

td/telegram/files/FileLocation.hpp

@@ -42,24 +42,48 @@ void PartialRemoteFileLocation::parse(ParserT &parser) {
 template <class StorerT>
 void PhotoRemoteFileLocation::store(StorerT &storer) const {
   using td::store;
+  bool has_secret = secret_ != 0;
+  bool has_source = source_.get_type() != PhotoSizeSource::Type::Empty;
+  BEGIN_STORE_FLAGS();
+  STORE_FLAG(has_secret);
+  STORE_FLAG(has_source);
+  END_STORE_FLAGS();
   store(id_, storer);
   store(access_hash_, storer);
   store(volume_id_, storer);
-  store(secret_, storer);
+  if (has_secret) {
+    store(secret_, storer);
+  }
   store(local_id_, storer);
-  store(source_, storer);
+  if (has_source) {
+    store(source_, storer);
+  }
 }
 
 template <class ParserT>
 void PhotoRemoteFileLocation::parse(ParserT &parser) {
   using td::parse;
+  bool has_secret = true;
+  bool has_source = false;
+  if (parser.version() >= static_cast<int32>(Version::AddPhotoSizeSource)) {
+    BEGIN_PARSE_FLAGS();
+    PARSE_FLAG(has_secret);
+    PARSE_FLAG(has_source);
+    END_PARSE_FLAGS();
+  }
   parse(id_, parser);
   parse(access_hash_, parser);
   parse(volume_id_, parser);
-  parse(secret_, parser);
+  if (has_secret) {
+    parse(secret_, parser);
+  } else {
+    secret_ = 0;
+  }
   parse(local_id_, parser);
-  if (parser.version() >= static_cast<int32>(Version::AddPhotoSizeSource)) {
+  if (has_source) {
     parse(source_, parser);
+  } else {
+    source_ = PhotoSizeSource();
   }
 }
 
@@ -177,31 +201,12 @@ void FullRemoteFileLocation::AsKey::store(StorerT &storer) const {
 
 template <class StorerT>
 void RemoteFileLocation::store(StorerT &storer) const {
-  storer.store_int(variant_.get_offset());
-  bool ok{false};
-  variant_.visit([&](auto &&value) {
-    using td::store;
-    store(value, storer);
-    ok = true;
-  });
-  CHECK(ok);
+  td::store(variant_, storer);
 }
 
 template <class ParserT>
 void RemoteFileLocation::parse(ParserT &parser) {
-  auto type = static_cast<Type>(parser.fetch_int());
-  switch (type) {
-    case Type::Empty:
-      variant_ = EmptyRemoteFileLocation();
-      return;
-    case Type::Partial:
-      variant_ = PartialRemoteFileLocation();
-      return partial().parse(parser);
-    case Type::Full:
-      variant_ = FullRemoteFileLocation();
-      return full().parse(parser);
-  }
-  parser.set_error("Invalid type in RemoteFileLocation");
+  td::parse(variant_, parser);
 }
 
 template <class StorerT>
@@ -261,32 +266,19 @@ void PartialLocalFileLocationPtr::store(StorerT &storer) const {
   td::store(*location_, storer);
 }
 
+template <class ParserT>
+void PartialLocalFileLocationPtr::parse(ParserT &parser) {
+  td::parse(*location_, parser);
+}
+
 template <class StorerT>
 void LocalFileLocation::store(StorerT &storer) const {
-  using td::store;
-  store(variant_.get_offset(), storer);
-  variant_.visit([&](auto &&value) {
-    using td::store;
-    store(value, storer);
-  });
+  td::store(variant_, storer);
 }
 
 template <class ParserT>
 void LocalFileLocation::parse(ParserT &parser) {
-  using td::parse;
-  auto type = static_cast<Type>(parser.fetch_int());
-  switch (type) {
-    case Type::Empty:
-      variant_ = EmptyLocalFileLocation();
-      return;
-    case Type::Partial:
-      variant_ = PartialLocalFileLocationPtr();
-      return parse(partial(), parser);
-    case Type::Full:
-      variant_ = FullLocalFileLocation();
-      return parse(full(), parser);
-  }
-  return parser.set_error("Invalid type in LocalFileLocation");
+  td::parse(variant_, parser);
 }
 
 template <class StorerT>

tdutils/td/utils/tl_helpers.h

@@ -14,6 +14,7 @@
 #include "td/utils/Status.h"
 #include "td/utils/tl_parsers.h"
 #include "td/utils/tl_storers.h"
+#include "td/utils/Variant.h"
 
 #include <type_traits>
 #include <unordered_set>
@@ -186,6 +187,29 @@ std::enable_if_t<!std::is_enum<T>::value> parse(T &val, ParserT &parser) {
   val.parse(parser);
 }
 
+template <class... Types, class StorerT>
+void store(const Variant<Types...> &variant, StorerT &storer) {
+  store(variant.get_offset(), storer);
+  variant.visit([&storer](auto &&value) {
+    using td::store;
+    store(value, storer);
+  });
+}
+template <class... Types, class ParserT>
+void parse(Variant<Types...> &variant, ParserT &parser) {
+  auto type_offset = parser.fetch_int();
+  if (type_offset < 0 || type_offset >= static_cast<int32>(sizeof...(Types))) {
+    return parser.set_error("Invalid type");
+  }
+  variant.for_each([type_offset, &parser, &variant](int offset, auto *ptr) {
+    using T = std::decay_t<decltype(*ptr)>;
+    if (offset == type_offset) {
+      variant = T();
+      parse(variant.get<T>(), parser);
+    }
+  });
+}
+
 template <class T>
 string serialize(const T &object) {
   TlStorerCalcLength calc_length;