Add parse_markdown_v2.

GitOrigin-RevId: ea2ce8bad64becc53d2e6466019469dffec2dc27
2019-10-03 02:31:06 +03:00 · 2019-10-03 02:31:06 +03:00 · fdf70df492
parent b1d1ea2e6c
commit fdf70df492
3 changed files with 378 additions and 48 deletions
--- a/td/telegram/MessageEntity.cpp
+++ b/td/telegram/MessageEntity.cpp
@ -28,71 +28,52 @@ int MessageEntity::get_type_priority(Type type) {
  return types[static_cast<int32>(type)];
 }

-StringBuilder &operator<<(StringBuilder &string_builder, const MessageEntity &message_entity) {
-  bool has_argument = false;
-  string_builder << '[';
-  switch (message_entity.type) {
+StringBuilder &operator<<(StringBuilder &string_builder, const MessageEntity::Type &message_entity_type) {
+  switch (message_entity_type) {
    case MessageEntity::Type::Mention:
-      string_builder << "Mention";
-      break;
+      return string_builder << "Mention";
    case MessageEntity::Type::Hashtag:
-      string_builder << "Hashtag";
-      break;
+      return string_builder << "Hashtag";
    case MessageEntity::Type::BotCommand:
-      string_builder << "BotCommand";
-      break;
+      return string_builder << "BotCommand";
    case MessageEntity::Type::Url:
-      string_builder << "Url";
-      break;
+      return string_builder << "Url";
    case MessageEntity::Type::EmailAddress:
-      string_builder << "EmailAddress";
-      break;
+      return string_builder << "EmailAddress";
    case MessageEntity::Type::Bold:
-      string_builder << "Bold";
-      break;
+      return string_builder << "Bold";
    case MessageEntity::Type::Italic:
-      string_builder << "Italic";
-      break;
+      return string_builder << "Italic";
    case MessageEntity::Type::Underline:
-      string_builder << "Underline";
-      break;
+      return string_builder << "Underline";
    case MessageEntity::Type::Strikethrough:
-      string_builder << "Strikethrough";
-      break;
+      return string_builder << "Strikethrough";
    case MessageEntity::Type::BlockQuote:
-      string_builder << "BlockQuote";
-      break;
+      return string_builder << "BlockQuote";
    case MessageEntity::Type::Code:
-      string_builder << "Code";
-      break;
+      return string_builder << "Code";
    case MessageEntity::Type::Pre:
-      string_builder << "Pre";
-      break;
+      return string_builder << "Pre";
    case MessageEntity::Type::PreCode:
-      string_builder << "PreCode";
-      has_argument = true;
-      break;
+      return string_builder << "PreCode";
    case MessageEntity::Type::TextUrl:
-      string_builder << "TextUrl";
-      has_argument = true;
-      break;
+      return string_builder << "TextUrl";
    case MessageEntity::Type::MentionName:
-      string_builder << "MentionName";
-      break;
+      return string_builder << "MentionName";
    case MessageEntity::Type::Cashtag:
-      string_builder << "Cashtag";
-      break;
+      return string_builder << "Cashtag";
    case MessageEntity::Type::PhoneNumber:
-      string_builder << "PhoneNumber";
-      break;
+      return string_builder << "PhoneNumber";
    default:
      UNREACHABLE();
-      string_builder << "Impossible";
-      break;
+      return string_builder << "Impossible";
  }
+}

-  string_builder << ", offset = " << message_entity.offset << ", length = " << message_entity.length;
-  if (has_argument) {
+StringBuilder &operator<<(StringBuilder &string_builder, const MessageEntity &message_entity) {
+  string_builder << '[' << message_entity.type << ", offset = " << message_entity.offset
+                 << ", length = " << message_entity.length;
+  if (!message_entity.argument.empty()) {
    string_builder << ", argument = \"" << message_entity.argument << "\"";
  }
  if (message_entity.user_id.is_valid()) {
@ -1322,7 +1303,7 @@ Result<vector<MessageEntity>> parse_markdown(string &text) {
      i += 2;
      is_pre = true;
      size_t language_end = i;
-      while (language_end < size && !is_space(text[language_end]) && text[language_end] != '`') {
+      while (!is_space(text[language_end]) && text[language_end] != '`') {
        language_end++;
      }
      if (i != language_end && language_end < size && text[language_end] != '`') {
@ -1405,7 +1386,224 @@ Result<vector<MessageEntity>> parse_markdown(string &text) {
  return entities;
 }

-static uint32 decode_html_entity(Slice text, size_t &pos) {
+static Result<vector<MessageEntity>> do_parse_markdown_v2(CSlice text, string &result) {
+  vector<MessageEntity> entities;
+  int32 utf16_offset = 0;
+
+  struct EntityInfo {
+    MessageEntity::Type type;
+    string argument;
+    int32 entity_offset;
+    size_t entity_byte_offset;
+    size_t entity_begin_pos;
+
+    EntityInfo(MessageEntity::Type type, string argument, int32 entity_offset, size_t entity_byte_offset,
+               size_t entity_begin_pos)
+        : type(type)
+        , argument(std::move(argument))
+        , entity_offset(entity_offset)
+        , entity_byte_offset(entity_byte_offset)
+        , entity_begin_pos(entity_begin_pos) {
+    }
+  };
+  std::vector<EntityInfo> nested_entities;
+
+  for (size_t i = 0; i < text.size(); i++) {
+    auto c = static_cast<unsigned char>(text[i]);
+    if (c == '\\' && text[i + 1] > 0 && text[i + 1] <= 126) {
+      i++;
+      utf16_offset += 1;
+      result += text[i];
+      continue;
+    }
+
+    Slice reserved_characters("_*[]()~`>#+=|{}.!");
+    if (!nested_entities.empty()) {
+      switch (nested_entities.back().type) {
+        case MessageEntity::Type::Code:
+        case MessageEntity::Type::Pre:
+        case MessageEntity::Type::PreCode:
+          reserved_characters = Slice("`");
+          break;
+        default:
+          break;
+      }
+    }
+
+    if (reserved_characters.find(text[i]) == Slice::npos) {
+      if (is_utf8_character_first_code_unit(c)) {
+        utf16_offset += 1 + (c >= 0xf0);  // >= 4 bytes in symbol => surrogaite pair
+      }
+      result.push_back(text[i]);
+      continue;
+    }
+
+    bool is_end_of_an_entity = false;
+    if (!nested_entities.empty()) {
+      is_end_of_an_entity = [&] {
+        switch (nested_entities.back().type) {
+          case MessageEntity::Type::Bold:
+            return c == '*';
+          case MessageEntity::Type::Italic:
+            return c == '_' && text[i + 1] != '_';
+          case MessageEntity::Type::Code:
+            return c == '`';
+          case MessageEntity::Type::Pre:
+          case MessageEntity::Type::PreCode:
+            return c == '`' && text[i + 1] == '`' && text[i + 2] == '`';
+          case MessageEntity::Type::TextUrl:
+            return c == ']';
+          case MessageEntity::Type::Underline:
+            return c == '_' && text[i + 1] == '_';
+          case MessageEntity::Type::Strikethrough:
+            return c == '~';
+          default:
+            UNREACHABLE();
+            return false;
+        }
+      }();
+    }
+
+    if (!is_end_of_an_entity) {
+      // begin of an entity
+      MessageEntity::Type type;
+      string argument;
+      int32 entity_byte_offset = i;
+      switch (c) {
+        case '_':
+          if (text[i + 1] == '_') {
+            type = MessageEntity::Type::Underline;
+            i++;
+          } else {
+            type = MessageEntity::Type::Italic;
+          }
+          break;
+        case '*':
+          type = MessageEntity::Type::Bold;
+          break;
+        case '~':
+          type = MessageEntity::Type::Strikethrough;
+          break;
+        case '[':
+          type = MessageEntity::Type::TextUrl;
+          break;
+        case '`':
+          if (text[i + 1] == '`' && text[i + 2] == '`') {
+            i += 3;
+            type = MessageEntity::Type::Pre;
+            size_t language_end = i;
+            while (!is_space(text[language_end]) && text[language_end] != '`') {
+              language_end++;
+            }
+            if (i != language_end && language_end < text.size() && text[language_end] != '`') {
+              type = MessageEntity::Type::PreCode;
+              argument = text.substr(i, language_end - i).str();
+              i = language_end;
+            }
+            // skip one new line in the beginning of the text
+            if (text[i] == '\n' || text[i] == '\r') {
+              if ((text[i + 1] == '\n' || text[i + 1] == '\r') && text[i] != text[i + 1]) {
+                i += 2;
+              } else {
+                i++;
+              }
+            }
+
+            i--;
+          } else {
+            type = MessageEntity::Type::Code;
+          }
+          break;
+        default:
+          return Status::Error(
+              400, PSLICE() << "Character '" << text[i] << "' is reserved and must be escaped with the preceding '\\'");
+      }
+      nested_entities.emplace_back(type, std::move(argument), utf16_offset, entity_byte_offset, result.size());
+    } else {
+      // end of an entity
+      auto type = nested_entities.back().type;
+      auto argument = std::move(nested_entities.back().argument);
+      UserId user_id;
+      bool skip_entity = utf16_offset == nested_entities.back().entity_offset;
+      switch (type) {
+        case MessageEntity::Type::Bold:
+        case MessageEntity::Type::Italic:
+        case MessageEntity::Type::Code:
+        case MessageEntity::Type::Strikethrough:
+          break;
+        case MessageEntity::Type::Underline:
+          i++;
+          break;
+        case MessageEntity::Type::Pre:
+        case MessageEntity::Type::PreCode:
+          i += 2;
+          break;
+        case MessageEntity::Type::TextUrl: {
+          string url;
+          if (text[i + 1] != '(') {
+            // use text as a url
+            url = result.substr(nested_entities.back().entity_begin_pos);
+          } else {
+            i += 2;
+            auto url_begin_pos = i;
+            while (i < text.size() && text[i] != ')') {
+              if (text[i] == '\\' && text[i + 1] > 0 && text[i + 1] <= 126) {
+                url += text[i + 1];
+                i += 2;
+                continue;
+              }
+              url += text[i++];
+            }
+            if (text[i] != ')') {
+              return Status::Error(400, PSLICE() << "Can't find end of a URL at byte offset " << url_begin_pos);
+            }
+          }
+          user_id = get_link_user_id(url);
+          if (!user_id.is_valid()) {
+            auto r_url = check_url(url);
+            if (r_url.is_error()) {
+              skip_entity = true;
+            } else {
+              argument = r_url.move_as_ok();
+            }
+          }
+          break;
+        }
+        default:
+          UNREACHABLE();
+          return false;
+      }
+
+      if (!skip_entity) {
+        auto entity_offset = nested_entities.back().entity_offset;
+        auto entity_length = utf16_offset - entity_offset;
+        if (user_id.is_valid()) {
+          entities.emplace_back(entity_offset, entity_length, user_id);
+        } else {
+          entities.emplace_back(type, entity_offset, entity_length, std::move(argument));
+        }
+      }
+      nested_entities.pop_back();
+    }
+  }
+  if (!nested_entities.empty()) {
+    return Status::Error(400, PSLICE() << "Can't find end of " << nested_entities.back().type
+                                       << " entity at byte offset " << nested_entities.back().entity_byte_offset);
+  }
+
+  std::sort(entities.begin(), entities.end());
+
+  return entities;
+}
+
+Result<vector<MessageEntity>> parse_markdown_v2(string &text) {
+  string result;
+  TRY_RESULT(entities, do_parse_markdown_v2(text, result));
+  text = result;
+  return entities;
+}
+
+static uint32 decode_html_entity(CSlice text, size_t &pos) {
  auto c = static_cast<unsigned char>(text[pos]);
  if (c != '&') {
    return 0;
@ -1458,7 +1656,7 @@ static uint32 decode_html_entity(Slice text, size_t &pos) {
  return res;
 }

-static Result<vector<MessageEntity>> do_parse_html(Slice text, string &result) {
+static Result<vector<MessageEntity>> do_parse_html(CSlice text, string &result) {
  vector<MessageEntity> entities;
  int32 utf16_offset = 0;

--- a/td/telegram/MessageEntity.h
+++ b/td/telegram/MessageEntity.h
@ -97,6 +97,8 @@ class MessageEntity {
  static int get_type_priority(Type type);
 };

+StringBuilder &operator<<(StringBuilder &string_builder, const MessageEntity::Type &message_entity_type);
+
 StringBuilder &operator<<(StringBuilder &string_builder, const MessageEntity &message_entity);

 struct FormattedText {
@ -140,6 +142,8 @@ string get_first_url(Slice text, const vector<MessageEntity> &entities);

 Result<vector<MessageEntity>> parse_markdown(string &text);

+Result<vector<MessageEntity>> parse_markdown_v2(string &text);
+
 Result<vector<MessageEntity>> parse_html(string &text);

 vector<tl_object_ptr<telegram_api::MessageEntity>> get_input_message_entities(const ContactsManager *contacts_manager,
--- a/test/message_entities.cpp
+++ b/test/message_entities.cpp
@ -6,6 +6,7 @@
 //
 #include "td/telegram/MessageEntity.h"

+#include "td/utils/common.h"
 #include "td/utils/format.h"
 #include "td/utils/logging.h"
 #include "td/utils/tests.h"
@ -730,7 +731,7 @@ static void check_parse_html(td::string text, const td::string &result, const td
  ASSERT_STREQ(result, text);
 }

-static void check_parse_html(td::string text, const td::string &error_message) {
+static void check_parse_html(td::string text, td::Slice error_message) {
  auto r_entities = td::parse_html(text);
  ASSERT_TRUE(r_entities.is_error());
  ASSERT_EQ(400, r_entities.error().code());
@ -764,6 +765,8 @@ TEST(MessageEntities, parse_html) {
  check_parse_html("&lt;&gt;&amp;&quot;&laquo;&raquo;&#12345678;", "<>&\"&laquo;&raquo;&#12345678;", {});
  check_parse_html("➡️ ➡️<i>➡️ ➡️</i>", "➡️ ➡️➡️ ➡️",
                   {{td::MessageEntity::Type::Italic, 5, 5}});
+  check_parse_html("➡️ ➡️<i>➡️ ➡️</i><b>➡️ ➡️</b>", "➡️ ➡️➡️ ➡️➡️ ➡️",
+                   {{td::MessageEntity::Type::Italic, 5, 5}, {td::MessageEntity::Type::Bold, 10, 5}});
  check_parse_html("🏟 🏟<i>🏟 &lt🏟</i>", "🏟 🏟🏟 <🏟", {{td::MessageEntity::Type::Italic, 5, 6}});
  check_parse_html("🏟 🏟<i>🏟 &gt;<b aba   =   caba>&lt🏟</b></i>", "🏟 🏟🏟 ><🏟",
                   {{td::MessageEntity::Type::Italic, 5, 7}, {td::MessageEntity::Type::Bold, 9, 3}});
@ -777,6 +780,8 @@ TEST(MessageEntities, parse_html) {
                   {{td::MessageEntity::Type::Italic, 6, 1}});
  check_parse_html("🏟 🏟&lt;<i    aba  =  '&lt;&gt;&quot;'>a</>", "🏟 🏟<a",
                   {{td::MessageEntity::Type::Italic, 6, 1}});
+  check_parse_html("🏟 🏟&lt;<i>🏟 🏟&lt;</>", "🏟 🏟<🏟 🏟<",
+                   {{td::MessageEntity::Type::Italic, 6, 6}});
  check_parse_html("🏟 🏟&lt;<i>a</    >", "🏟 🏟<a", {{td::MessageEntity::Type::Italic, 6, 1}});
  check_parse_html("🏟 🏟&lt;<i>a</i   >", "🏟 🏟<a", {{td::MessageEntity::Type::Italic, 6, 1}});
  check_parse_html("🏟 🏟&lt;<b></b>", "🏟 🏟<", {});
@ -806,3 +811,126 @@ TEST(MessageEntities, parse_html) {
  check_parse_html("<a>https://telegram.org/asdsa?asdasdwe#12e3we</a>", "https://telegram.org/asdsa?asdasdwe#12e3we",
                   {{td::MessageEntity::Type::TextUrl, 0, 42, "https://telegram.org/asdsa?asdasdwe#12e3we"}});
 }
+
+static void check_parse_markdown(td::string text, const td::string &result,
+                                 const td::vector<td::MessageEntity> &entities) {
+  auto r_entities = td::parse_markdown_v2(text);
+  ASSERT_TRUE(r_entities.is_ok());
+  ASSERT_EQ(entities, r_entities.ok());
+  ASSERT_STREQ(result, text);
+}
+
+static void check_parse_markdown(td::string text, td::Slice error_message) {
+  auto r_entities = td::parse_markdown_v2(text);
+  ASSERT_TRUE(r_entities.is_error());
+  ASSERT_EQ(400, r_entities.error().code());
+  ASSERT_STREQ(error_message, r_entities.error().message());
+}
+
+TEST(MessageEntities, parse_markdown) {
+  td::Slice reserved_characters("]()>#+=|{}.!");
+  td::Slice begin_characters("_*[~`");
+  for (char c = 1; c < 126; c++) {
+    if (begin_characters.find(c) != td::Slice::npos) {
+      continue;
+    }
+
+    td::string text(1, c);
+    if (reserved_characters.find(c) == td::Slice::npos) {
+      check_parse_markdown(text, text, {});
+    } else {
+      check_parse_markdown(
+          text, PSLICE() << "Character '" << c << "' is reserved and must be escaped with the preceding '\\'");
+
+      td::string escaped_text = "\\" + text;
+      check_parse_markdown(escaped_text, text, {});
+    }
+  }
+
+  check_parse_markdown("🏟 🏟_abacaba", "Can't find end of Italic entity at byte offset 9");
+  check_parse_markdown("🏟 🏟_abac * asd ", "Can't find end of Bold entity at byte offset 15");
+  check_parse_markdown("🏟 🏟_abac * asd _", "Can't find end of Italic entity at byte offset 21");
+  check_parse_markdown("🏟 🏟`", "Can't find end of Code entity at byte offset 9");
+  check_parse_markdown("🏟 🏟```", "Can't find end of Pre entity at byte offset 9");
+  check_parse_markdown("🏟 🏟```a", "Can't find end of Pre entity at byte offset 9");
+  check_parse_markdown("🏟 🏟```a ", "Can't find end of PreCode entity at byte offset 9");
+  check_parse_markdown("🏟 🏟__🏟 🏟_", "Can't find end of Italic entity at byte offset 20");
+  check_parse_markdown("🏟 🏟_🏟 🏟__", "Can't find end of Underline entity at byte offset 19");
+  check_parse_markdown("🏟 🏟```🏟 🏟`", "Can't find end of Code entity at byte offset 21");
+  check_parse_markdown("🏟 🏟```🏟 🏟_", "Can't find end of PreCode entity at byte offset 9");
+  check_parse_markdown("🏟 🏟```🏟 🏟\\`", "Can't find end of PreCode entity at byte offset 9");
+  check_parse_markdown("[telegram\\.org](asd\\)", "Can't find end of a URL at byte offset 16");
+  check_parse_markdown("[telegram\\.org](", "Can't find end of a URL at byte offset 16");
+  check_parse_markdown("[telegram\\.org](asd", "Can't find end of a URL at byte offset 16");
+  check_parse_markdown("🏟 🏟__🏟 _🏟___", "Can't find end of Italic entity at byte offset 23");
+  check_parse_markdown("🏟 🏟__", "Can't find end of Underline entity at byte offset 9");
+
+  check_parse_markdown("", "", {});
+  check_parse_markdown("\\\\", "\\", {});
+  check_parse_markdown("\\\\\\", "\\\\", {});
+  check_parse_markdown("\\\\\\\\\\_\\*\\`", "\\\\_*`", {});
+  check_parse_markdown("➡️ ➡️", "➡️ ➡️", {});
+  check_parse_markdown("🏟 🏟``", "🏟 🏟", {});
+  check_parse_markdown("🏟 🏟_abac \\* asd _", "🏟 🏟abac * asd ", {{td::MessageEntity::Type::Italic, 5, 11}});
+  check_parse_markdown("🏟 \\.🏟_🏟\\. 🏟_", "🏟 .🏟🏟. 🏟", {{td::MessageEntity::Type::Italic, 6, 6}});
+  check_parse_markdown("\\\\\\a\\b\\c\\d\\e\\f\\1\\2\\3\\4\\➡️\\", "\\abcdef1234\\➡️\\", {});
+  check_parse_markdown("➡️ ➡️_➡️ ➡️_", "➡️ ➡️➡️ ➡️",
+                       {{td::MessageEntity::Type::Italic, 5, 5}});
+  check_parse_markdown("➡️ ➡️_➡️ ➡️_*➡️ ➡️*", "➡️ ➡️➡️ ➡️➡️ ➡️",
+                       {{td::MessageEntity::Type::Italic, 5, 5}, {td::MessageEntity::Type::Bold, 10, 5}});
+  check_parse_markdown("🏟 🏟_🏟 \\.🏟_", "🏟 🏟🏟 .🏟", {{td::MessageEntity::Type::Italic, 5, 6}});
+  check_parse_markdown("🏟 🏟_🏟 *🏟*_", "🏟 🏟🏟 🏟",
+                       {{td::MessageEntity::Type::Italic, 5, 5}, {td::MessageEntity::Type::Bold, 8, 2}});
+  check_parse_markdown("🏟 🏟_🏟 __🏟___", "🏟 🏟🏟 🏟",
+                       {{td::MessageEntity::Type::Italic, 5, 5}, {td::MessageEntity::Type::Underline, 8, 2}});
+  check_parse_markdown("🏟 🏟__🏟 _🏟_ __", "🏟 🏟🏟 🏟 ",
+                       {{td::MessageEntity::Type::Underline, 5, 6}, {td::MessageEntity::Type::Italic, 8, 2}});
+  check_parse_markdown("🏟 🏟__🏟 _🏟_\\___", "🏟 🏟🏟 🏟_",
+                       {{td::MessageEntity::Type::Underline, 5, 6}, {td::MessageEntity::Type::Italic, 8, 2}});
+  check_parse_markdown("🏟 🏟`🏟 🏟```", "🏟 🏟🏟 🏟", {{td::MessageEntity::Type::Code, 5, 5}});
+  check_parse_markdown("🏟 🏟```🏟 🏟```", "🏟 🏟 🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 3, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\n🏟```", "🏟 🏟🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 2, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\r🏟```", "🏟 🏟🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 2, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\n\r🏟```", "🏟 🏟🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 2, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\r\n🏟```", "🏟 🏟🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 2, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\n\n🏟```", "🏟 🏟\n🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 3, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟\r\r🏟```", "🏟 🏟\r🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 3, "🏟"}});
+  check_parse_markdown("🏟 🏟```🏟 \\\\\\`🏟```", "🏟 🏟 \\`🏟",
+                       {{td::MessageEntity::Type::PreCode, 5, 5, "🏟"}});
+  check_parse_markdown("🏟 🏟**", "🏟 🏟", {});
+  check_parse_markdown("🏟 🏟``", "🏟 🏟", {});
+  check_parse_markdown("🏟 🏟``````", "🏟 🏟", {});
+  check_parse_markdown("🏟 🏟____", "🏟 🏟", {});
+  check_parse_markdown("`_* *_`__*` `*__", "_* *_ ",
+                       {{td::MessageEntity::Type::Code, 0, 5},
+                        {td::MessageEntity::Type::Code, 5, 1},
+                        {td::MessageEntity::Type::Bold, 5, 1},
+                        {td::MessageEntity::Type::Underline, 5, 1}});
+  check_parse_markdown("_* * ` `_", "   ",
+                       {{td::MessageEntity::Type::Italic, 0, 3},
+                        {td::MessageEntity::Type::Bold, 0, 1},
+                        {td::MessageEntity::Type::Code, 2, 1}});
+  check_parse_markdown("[](telegram.org)", "", {});
+  check_parse_markdown("[ ](telegram.org)", " ", {{td::MessageEntity::Type::TextUrl, 0, 1, "http://telegram.org/"}});
+  check_parse_markdown("[ ](as)", " ", {});
+  check_parse_markdown("[telegram\\.org]", "telegram.org",
+                       {{td::MessageEntity::Type::TextUrl, 0, 12, "http://telegram.org/"}});
+  check_parse_markdown("[telegram\\.org]a", "telegram.orga",
+                       {{td::MessageEntity::Type::TextUrl, 0, 12, "http://telegram.org/"}});
+  check_parse_markdown("[telegram\\.org](telegram.dog)", "telegram.org",
+                       {{td::MessageEntity::Type::TextUrl, 0, 12, "http://telegram.dog/"}});
+  check_parse_markdown("[telegram\\.org](https://telegram.dog?)", "telegram.org",
+                       {{td::MessageEntity::Type::TextUrl, 0, 12, "https://telegram.dog/?"}});
+  check_parse_markdown("[telegram\\.org](https://telegram.dog?\\\\\\()", "telegram.org",
+                       {{td::MessageEntity::Type::TextUrl, 0, 12, "https://telegram.dog/?\\("}});
+  check_parse_markdown("[telegram\\.org]()", "telegram.org", {});
+  check_parse_markdown("[telegram\\.org](asdasd)", "telegram.org", {});
+  check_parse_markdown("[telegram\\.org](tg:user?id=123456)", "telegram.org", {{0, 12, td::UserId(123456)}});
+}