Add td_api::getMarkdownText.

GitOrigin-RevId: b463cc2c92052c552d66d774450ffa7bb4bc132e

td/generate/scheme/td_api.tl

@@ -3428,6 +3428,9 @@ parseTextEntities text:string parse_mode:TextParseMode = FormattedText;
 //@text The text to parse. For example, "__italic__ ~~strikethrough~~ **bold** `code` ```pre``` __[italic__ text_url](telegram.org) __italic**bold italic__bold**"
 parseMarkdown text:formattedText = FormattedText;
 
+//@description Replaces text entities with Markdown formatting in a human-friendly format. Entities that can't be represented in Markdown unambiguously are kept as is. This is an offline method. Can be called before authorization. Can be called synchronously @text The text
+getMarkdownText text:formattedText = FormattedText;
+
 //@description Returns the MIME type of a file, guessed by its extension. Returns an empty string on failure. This is an offline method. Can be called before authorization. Can be called synchronously @file_name The name of the file or path to the file
 getFileMimeType file_name:string = Text;
 

td/telegram/MessageEntity.cpp

@@ -1204,6 +1204,12 @@ static constexpr int32 get_pre_entities_mask() {
          get_entity_type_mask(MessageEntity::Type::PreCode);
 }
 
+static constexpr int32 get_user_entities_mask() {
+  return get_splittable_entities_mask() | get_blockquote_entities_mask() |
+         get_entity_type_mask(MessageEntity::Type::TextUrl) | get_entity_type_mask(MessageEntity::Type::MentionName) |
+         get_pre_entities_mask();
+}
+
 static int32 is_splittable_entity(MessageEntity::Type type) {
   return (get_entity_type_mask(type) & get_splittable_entities_mask()) != 0;
 }
@@ -1220,6 +1226,10 @@ static int32 is_pre_entity(MessageEntity::Type type) {
   return (get_entity_type_mask(type) & get_pre_entities_mask()) != 0;
 }
 
+static int32 is_user_entity(MessageEntity::Type type) {
+  return (get_entity_type_mask(type) & get_user_entities_mask()) != 0;
+}
+
 static constexpr size_t SPLITTABLE_ENTITY_TYPE_COUNT = 4;
 
 static size_t get_splittable_entity_type_index(MessageEntity::Type type) {
@@ -2118,6 +2128,13 @@ static vector<MessageEntity> find_splittable_entities_v3(Slice text, const vecto
   for (auto &entity : entities) {
     unallowed_boundaries.insert(entity.offset);
     unallowed_boundaries.insert(entity.offset + entity.length);
+    if (entity.type == MessageEntity::Type::Mention || entity.type == MessageEntity::Type::Hashtag ||
+        entity.type == MessageEntity::Type::BotCommand || entity.type == MessageEntity::Type::Cashtag ||
+        entity.type == MessageEntity::Type::PhoneNumber || entity.type == MessageEntity::Type::BankCardNumber) {
+      for (int32 i = 1; i < entity.length; i++) {
+        unallowed_boundaries.insert(entity.offset + i);
+      }
+    }
   }
 
   auto found_entities = find_entities(text, false, false);
@@ -2440,6 +2457,128 @@ FormattedText parse_markdown_v3(FormattedText text) {
   return result;
 }
 
+// text entities must be valid
+FormattedText get_markdown_v3(FormattedText text) {
+  if (text.entities.empty()) {
+    return text;
+  }
+
+  check_is_sorted(text.entities);
+  for (auto &entity : text.entities) {
+    if (!is_user_entity(entity.type)) {
+      return text;
+    }
+  }
+
+  FormattedText result;
+  struct EntityInfo {
+    const MessageEntity *entity;
+    int32 utf16_added_before;
+
+    EntityInfo(MessageEntity *entity, int32 utf16_added_before)
+        : entity(entity), utf16_added_before(utf16_added_before) {
+    }
+  };
+  vector<EntityInfo> nested_entities_stack;
+  size_t current_entity = 0;
+
+  int32 utf16_offset = 0;
+  int32 utf16_added = 0;
+
+  for (size_t pos = 0; pos <= text.text.size(); pos++) {
+    auto c = static_cast<unsigned char>(text.text[pos]);
+    if (is_utf8_character_first_code_unit(c)) {
+      while (!nested_entities_stack.empty()) {
+        const auto *entity = nested_entities_stack.back().entity;
+        auto entity_end = entity->offset + entity->length;
+        if (utf16_offset < entity_end) {
+          break;
+        }
+
+        CHECK(utf16_offset == entity_end);
+
+        switch (entity->type) {
+          case MessageEntity::Type::Italic:
+            result.text += "__";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::Bold:
+            result.text += "**";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::Strikethrough:
+            result.text += "~~";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::TextUrl:
+            result.text += "](";
+            result.text += entity->argument;
+            result.text += ')';
+            utf16_added += 3 + entity->argument.size();
+            break;
+          case MessageEntity::Type::Code:
+            result.text += '`';
+            utf16_added++;
+            break;
+          case MessageEntity::Type::Pre:
+            result.text += "```";
+            utf16_added += 3;
+            break;
+          default:
+            result.entities.push_back(*entity);
+            result.entities.back().offset += nested_entities_stack.back().utf16_added_before;
+            result.entities.back().length += utf16_added - nested_entities_stack.back().utf16_added_before;
+            break;
+        }
+        nested_entities_stack.pop_back();
+      }
+
+      while (current_entity < text.entities.size() && utf16_offset >= text.entities[current_entity].offset) {
+        CHECK(utf16_offset == text.entities[current_entity].offset);
+        switch (text.entities[current_entity].type) {
+          case MessageEntity::Type::Italic:
+            result.text += "__";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::Bold:
+            result.text += "**";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::Strikethrough:
+            result.text += "~~";
+            utf16_added += 2;
+            break;
+          case MessageEntity::Type::TextUrl:
+            result.text += '[';
+            utf16_added++;
+            break;
+          case MessageEntity::Type::Code:
+            result.text += '`';
+            utf16_added++;
+            break;
+          case MessageEntity::Type::Pre:
+            result.text += "```";
+            utf16_added += 3;
+            break;
+        }
+        nested_entities_stack.emplace_back(&text.entities[current_entity++], utf16_added);
+      }
+      utf16_offset += 1 + (c >= 0xf0);  // >= 4 bytes in symbol => surrogaite pair
+    }
+    if (pos == text.text.size()) {
+      break;
+    }
+
+    result.text.push_back(text.text[pos]);
+  }
+
+  sort_entities(result.entities);
+  if (parse_markdown_v3(result) != text) {
+    return text;
+  }
+  return result;
+}
+
 static uint32 decode_html_entity(CSlice text, size_t &pos) {
   auto c = static_cast<unsigned char>(text[pos]);
   if (c != '&') {
@@ -2730,16 +2869,10 @@ vector<tl_object_ptr<telegram_api::MessageEntity>> get_input_message_entities(co
                                                                               const char *source) {
   vector<tl_object_ptr<telegram_api::MessageEntity>> result;
   for (auto &entity : entities) {
-    switch (entity.type) {
+    if (!is_user_entity(entity.type)) {
-      case MessageEntity::Type::Mention:
-      case MessageEntity::Type::Hashtag:
-      case MessageEntity::Type::BotCommand:
-      case MessageEntity::Type::Url:
-      case MessageEntity::Type::EmailAddress:
-      case MessageEntity::Type::Cashtag:
-      case MessageEntity::Type::PhoneNumber:
-      case MessageEntity::Type::BankCardNumber:
       continue;
+    }
+    switch (entity.type) {
       case MessageEntity::Type::Bold:
         result.push_back(make_tl_object<telegram_api::messageEntityBold>(entity.offset, entity.length));
         break;
@@ -2775,6 +2908,14 @@ vector<tl_object_ptr<telegram_api::MessageEntity>> get_input_message_entities(co
                                                                                      std::move(input_user)));
         break;
       }
+      case MessageEntity::Type::Mention:
+      case MessageEntity::Type::Hashtag:
+      case MessageEntity::Type::BotCommand:
+      case MessageEntity::Type::Url:
+      case MessageEntity::Type::EmailAddress:
+      case MessageEntity::Type::Cashtag:
+      case MessageEntity::Type::PhoneNumber:
+      case MessageEntity::Type::BankCardNumber:
       default:
         UNREACHABLE();
     }
@@ -2872,44 +3013,28 @@ Result<vector<MessageEntity>> get_message_entities(const ContactsManager *contac
 
     switch (entity->type_->get_id()) {
       case td_api::textEntityTypeMention::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::Mention, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeHashtag::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::Hashtag, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeBotCommand::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::BotCommand, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeUrl::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::Url, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeEmailAddress::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::EmailAddress, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeCashtag::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::Cashtag, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypePhoneNumber::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::PhoneNumber, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeBankCardNumber::ID:
-        if (allow_all) {
         entities.emplace_back(MessageEntity::Type::BankCardNumber, entity->offset_, entity->length_);
-        }
         break;
       case td_api::textEntityTypeBold::ID:
         entities.emplace_back(MessageEntity::Type::Bold, entity->offset_, entity->length_);
@@ -2962,6 +3087,10 @@ Result<vector<MessageEntity>> get_message_entities(const ContactsManager *contac
       default:
         UNREACHABLE();
     }
+    CHECK(!entities.empty());
+    if (!allow_all && !is_user_entity(entities.back().type)) {
+      entities.pop_back();
+    }
   }
   return entities;
 }

td/telegram/MessageEntity.h

@@ -151,6 +151,8 @@ Result<vector<MessageEntity>> parse_markdown_v2(string &text);
 
 FormattedText parse_markdown_v3(FormattedText text);
 
+FormattedText get_markdown_v3(FormattedText text);
+
 Result<vector<MessageEntity>> parse_html(string &text);
 
 vector<tl_object_ptr<telegram_api::MessageEntity>> get_input_message_entities(const ContactsManager *contacts_manager,

td/telegram/Td.cpp

@@ -3081,6 +3081,7 @@ bool Td::is_synchronous_request(int32 id) {
     case td_api::getTextEntities::ID:
     case td_api::parseTextEntities::ID:
     case td_api::parseMarkdown::ID:
+    case td_api::getMarkdownText::ID:
     case td_api::getFileMimeType::ID:
     case td_api::getFileExtension::ID:
     case td_api::cleanFileName::ID:
@@ -3304,6 +3305,7 @@ td_api::object_ptr<td_api::Object> Td::static_request(td_api::object_ptr<td_api:
     switch (function_id) {
       case td_api::parseTextEntities::ID:
       case td_api::parseMarkdown::ID:
+      case td_api::getMarkdownText::ID:
       case td_api::getFileMimeType::ID:
       case td_api::getFileExtension::ID:
       case td_api::cleanFileName::ID:
@@ -7453,6 +7455,10 @@ void Td::on_request(uint64 id, const td_api::parseMarkdown &request) {
   UNREACHABLE();
 }
 
+void Td::on_request(uint64 id, const td_api::getMarkdownText &request) {
+  UNREACHABLE();
+}
+
 void Td::on_request(uint64 id, const td_api::getFileMimeType &request) {
   UNREACHABLE();
 }
@@ -7572,8 +7578,25 @@ td_api::object_ptr<td_api::Object> Td::do_static_request(td_api::parseMarkdown &
 
   auto parsed_text = parse_markdown_v3({std::move(request.text_->text_), std::move(entities)});
   fix_formatted_text(parsed_text.text, parsed_text.entities, true, true, true, true).ensure();
-  return make_tl_object<td_api::formattedText>(std::move(parsed_text.text),
+  return get_formatted_text_object(parsed_text);
-                                               get_text_entities_object(parsed_text.entities));
+}
+
+td_api::object_ptr<td_api::Object> Td::do_static_request(td_api::getMarkdownText &request) {
+  if (request.text_ == nullptr) {
+    return make_error(400, "Text must be non-empty");
+  }
+
+  auto r_entities = get_message_entities(nullptr, std::move(request.text_->entities_));
+  if (r_entities.is_error()) {
+    return make_error(400, r_entities.error().message());
+  }
+  auto entities = r_entities.move_as_ok();
+  auto status = fix_formatted_text(request.text_->text_, entities, true, true, true, true);
+  if (status.is_error()) {
+    return make_error(400, status.error().message());
+  }
+
+  return get_formatted_text_object(get_markdown_v3({std::move(request.text_->text_), std::move(entities)}));
 }
 
 td_api::object_ptr<td_api::Object> Td::do_static_request(const td_api::getFileMimeType &request) {

td/telegram/Td.h

@@ -1047,6 +1047,8 @@ class Td final : public NetQueryCallback {
 
   void on_request(uint64 id, const td_api::parseMarkdown &request);
 
+  void on_request(uint64 id, const td_api::getMarkdownText &request);
+
   void on_request(uint64 id, const td_api::getFileMimeType &request);
 
   void on_request(uint64 id, const td_api::getFileExtension &request);
@@ -1099,6 +1101,7 @@ class Td final : public NetQueryCallback {
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::getTextEntities &request);
   static td_api::object_ptr<td_api::Object> do_static_request(td_api::parseTextEntities &request);
   static td_api::object_ptr<td_api::Object> do_static_request(td_api::parseMarkdown &request);
+  static td_api::object_ptr<td_api::Object> do_static_request(td_api::getMarkdownText &request);
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::getFileMimeType &request);
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::getFileExtension &request);
   static td_api::object_ptr<td_api::Object> do_static_request(const td_api::cleanFileName &request);

test/message_entities.cpp

@@ -1256,19 +1256,24 @@ TEST(MessageEntities, parse_markdown) {
   check_parse_markdown("[telegram\\.org](tg:user?id=123456)", "telegram.org", {{0, 12, td::UserId(123456)}});
 }
 
-static void check_parse_markdown_v3(td::string text, td::vector<td::MessageEntity> entities, const td::string &result,
+static void check_parse_markdown_v3(td::string text, td::vector<td::MessageEntity> entities,
-                                    const td::vector<td::MessageEntity> &result_entities, bool fix = false) {
+                                    const td::string &result_text, const td::vector<td::MessageEntity> &result_entities,
+                                    bool fix = false) {
   auto parsed_text = td::parse_markdown_v3({std::move(text), std::move(entities)});
   if (fix) {
     ASSERT_TRUE(fix_formatted_text(parsed_text.text, parsed_text.entities, true, true, true, true).is_ok());
   }
-  ASSERT_STREQ(result, parsed_text.text);
+  ASSERT_STREQ(result_text, parsed_text.text);
   ASSERT_EQ(result_entities, parsed_text.entities);
+  if (fix) {
+    auto markdown_text = td::get_markdown_v3(parsed_text);
+    ASSERT_TRUE(parsed_text == markdown_text || parsed_text == td::parse_markdown_v3(markdown_text));
+  }
 }
 
-static void check_parse_markdown_v3(td::string text, const td::string &result,
+static void check_parse_markdown_v3(td::string text, const td::string &result_text,
                                     const td::vector<td::MessageEntity> &result_entities, bool fix = false) {
-  check_parse_markdown_v3(std::move(text), td::vector<td::MessageEntity>(), result, result_entities, fix);
+  check_parse_markdown_v3(std::move(text), td::vector<td::MessageEntity>(), result_text, result_entities, fix);
 }
 
 TEST(MessageEntities, parse_markdown_v3) {
@@ -1293,6 +1298,9 @@ TEST(MessageEntities, parse_markdown_v3) {
   check_parse_markdown_v3("` `a", " a", {{td::MessageEntity::Type::Code, 0, 1}}, true);
   check_parse_markdown_v3("`\n`a", "\na", {}, true);
   check_parse_markdown_v3("``", "``", {});
+  check_parse_markdown_v3("`a````b```", "`a````b```", {});
+  check_parse_markdown_v3("ab", {{td::MessageEntity::Type::Code, 0, 1}, {td::MessageEntity::Type::Pre, 1, 1}}, "ab",
+                          {{td::MessageEntity::Type::Code, 0, 1}, {td::MessageEntity::Type::Pre, 1, 1}});
 
   check_parse_markdown_v3("[a](b[c](t.me)", "[a](b[c](t.me)", {});
   check_parse_markdown_v3("[](t.me)", "[](t.me)", {});
@@ -1411,6 +1419,9 @@ TEST(MessageEntities, parse_markdown_v3) {
                            {td::MessageEntity::Type::TextUrl, 3, 4, "http://t.me/"},
                            {td::MessageEntity::Type::Italic, 3, 2}},
                           true);
+  check_parse_markdown_v3("__a #test__test", "__a #test__test", {});
+  check_parse_markdown_v3("a #testtest", {{td::MessageEntity::Type::Italic, 0, 7}}, "a #testtest",
+                          {{td::MessageEntity::Type::Italic, 0, 7}});
 
   // TODO parse_markdown_v3 is not idempotent now, which is bad
   check_parse_markdown_v3(
@@ -1551,5 +1562,57 @@ TEST(MessageEntities, parse_markdown_v3) {
       text = std::move(parsed_text);
     }
     ASSERT_EQ(text, td::parse_markdown_v3(text));
+    auto markdown_text = td::get_markdown_v3(text);
+    ASSERT_TRUE(text == markdown_text || text == td::parse_markdown_v3(markdown_text));
   }
 }
+
+static void check_get_markdown_v3(td::string result_text, td::vector<td::MessageEntity> result_entities,
+                                  const td::string &text, const td::vector<td::MessageEntity> &entities) {
+  auto markdown_text = td::get_markdown_v3({std::move(text), std::move(entities)});
+  ASSERT_STREQ(result_text, markdown_text.text);
+  ASSERT_EQ(result_entities, markdown_text.entities);
+}
+
+TEST(MessageEntities, get_markdown_v3) {
+  check_get_markdown_v3("``` ```", {}, " ", {{td::MessageEntity::Type::Pre, 0, 1}});
+  check_get_markdown_v3("` `", {}, " ", {{td::MessageEntity::Type::Code, 0, 1}});
+  check_get_markdown_v3("`\n`", {}, "\n", {{td::MessageEntity::Type::Code, 0, 1}});
+  check_get_markdown_v3("ab", {{td::MessageEntity::Type::Code, 0, 1}, {td::MessageEntity::Type::Pre, 1, 1}}, "ab",
+                        {{td::MessageEntity::Type::Code, 0, 1}, {td::MessageEntity::Type::Pre, 1, 1}});
+
+  check_get_markdown_v3("[ ](http://t.me/)", {}, " ", {{td::MessageEntity::Type::TextUrl, 0, 1, "http://t.me/"}});
+  check_get_markdown_v3("[ ]t.me[)](http://t.me/) [ ](t.me)", {{25, 1, td::UserId(1)}}, "[ ]t.me) [ ](t.me)",
+                        {{td::MessageEntity::Type::TextUrl, 7, 1, "http://t.me/"}, {9, 1, td::UserId(1)}});
+
+  check_get_markdown_v3("__ __", {}, " ", {{td::MessageEntity::Type::Italic, 0, 1}});
+  check_get_markdown_v3("** **", {}, " ", {{td::MessageEntity::Type::Bold, 0, 1}});
+  check_get_markdown_v3("~~ ~~", {}, " ", {{td::MessageEntity::Type::Strikethrough, 0, 1}});
+  check_get_markdown_v3("__a__ **b** ~~c~~ d", {{td::MessageEntity::Type::PreCode, 18, 1, "C++"}}, "a b c d",
+                        {{td::MessageEntity::Type::Italic, 0, 1},
+                         {td::MessageEntity::Type::Bold, 2, 1},
+                         {td::MessageEntity::Type::Strikethrough, 4, 1},
+                         {td::MessageEntity::Type::PreCode, 6, 1, "C++"}});
+  check_get_markdown_v3("`ab` ```cd``` ef", {{td::MessageEntity::Type::PreCode, 14, 2, "C++"}}, "ab cd ef",
+                        {{td::MessageEntity::Type::Code, 0, 2},
+                         {td::MessageEntity::Type::Pre, 3, 2},
+                         {td::MessageEntity::Type::PreCode, 6, 2, "C++"}});
+  check_get_markdown_v3("__asd__[__ab__cd](http://t.me/)", {}, "asdabcd",
+                        {{td::MessageEntity::Type::Italic, 0, 3},
+                         {td::MessageEntity::Type::TextUrl, 3, 4, "http://t.me/"},
+                         {td::MessageEntity::Type::Italic, 3, 2}});
+
+  check_get_markdown_v3("__ab", {{td::MessageEntity::Type::Italic, 3, 1}}, "__ab",
+                        {{td::MessageEntity::Type::Italic, 3, 1}});
+  check_get_markdown_v3("__ab__**__cd__**~~**__ef__gh**ij~~", {}, "abcdefghij",
+                        {{td::MessageEntity::Type::Italic, 0, 2},
+                         {td::MessageEntity::Type::Bold, 2, 2},
+                         {td::MessageEntity::Type::Italic, 2, 2},
+                         {td::MessageEntity::Type::Strikethrough, 4, 6},
+                         {td::MessageEntity::Type::Bold, 4, 4},
+                         {td::MessageEntity::Type::Italic, 4, 2}});
+  check_get_markdown_v3("[**__bold italic link__**](http://example.com/)", {}, "bold italic link",
+                        {{td::MessageEntity::Type::TextUrl, 0, 16, "http://example.com/"},
+                         {td::MessageEntity::Type::Bold, 0, 16},
+                         {td::MessageEntity::Type::Italic, 0, 16}});
+}