From 36ebd42a92620b3b7e9b192f79a4dfd33c985e8b Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Tue, 21 May 2024 11:50:41 +0300
Subject: [PATCH] Allow attributes without value and support expandable
 blockquote entities in HTML parse_mode.

---
 td/telegram/MessageEntity.cpp | 23 ++++++++++++++++++-----
 test/message_entities.cpp     | 11 ++++++++---
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/td/telegram/MessageEntity.cpp b/td/telegram/MessageEntity.cpp
index 76530e67c..0ce83e0ca 100644
--- a/td/telegram/MessageEntity.cpp
+++ b/td/telegram/MessageEntity.cpp
@@ -3261,7 +3261,8 @@ Result<vector<MessageEntity>> parse_html(string &str) {
           break;
         }
         auto attribute_begin_pos = i;
-        while (!is_space(text[i]) && text[i] != '=') {
+        while (!is_space(text[i]) && text[i] != '=' && text[i] != '>' && text[i] != '/' && text[i] != '"' &&
+               text[i] != '\'') {
           i++;
         }
         Slice attribute_name(text + attribute_begin_pos, i - attribute_begin_pos);
@@ -3273,8 +3274,14 @@ Result<vector<MessageEntity>> parse_html(string &str) {
           i++;
         }
         if (text[i] != '=') {
-          return Status::Error(400, PSLICE() << "Expected equal sign in declaration of an attribute of the tag \""
-                                             << tag_name << "\" at byte offset " << begin_pos);
+          if (text[i] == 0) {
+            return Status::Error(400, PSLICE()
+                                          << "Unclosed start tag \"" << tag_name << "\" at byte offset " << begin_pos);
+          }
+          if (tag_name == "blockquote" && attribute_name == Slice("expandable")) {
+            argument = "1";
+          }
+          continue;
         }
         i++;
         while (text[i] != 0 && is_space(text[i])) {
@@ -3331,6 +3338,8 @@ Result<vector<MessageEntity>> parse_html(string &str) {
           argument = attribute_value.substr(3);
         } else if (tag_name == "tg-emoji" && attribute_name == Slice("emoji-id")) {
           argument = std::move(attribute_value);
+        } else if (tag_name == "blockquote" && attribute_name == Slice("expandable")) {
+          argument = "1";
         }
       }
 
@@ -3416,7 +3425,11 @@ Result<vector<MessageEntity>> parse_html(string &str) {
                                   nested_entities.back().argument);
           }
         } else if (tag_name == "blockquote") {
-          entities.emplace_back(MessageEntity::Type::BlockQuote, entity_offset, entity_length);
+          if (!nested_entities.back().argument.empty()) {
+            entities.emplace_back(MessageEntity::Type::ExpandableBlockQuote, entity_offset, entity_length);
+          } else {
+            entities.emplace_back(MessageEntity::Type::BlockQuote, entity_offset, entity_length);
+          }
         } else {
           UNREACHABLE();
         }
@@ -3426,7 +3439,7 @@ Result<vector<MessageEntity>> parse_html(string &str) {
   }
   if (!nested_entities.empty()) {
     return Status::Error(
-        400, PSLICE() << "Can't find end tag corresponding to start tag " << nested_entities.back().tag_name);
+        400, PSLICE() << "Can't find end tag corresponding to start tag \"" << nested_entities.back().tag_name << '"');
   }
 
   for (auto &entity : entities) {
diff --git a/test/message_entities.cpp b/test/message_entities.cpp
index d0ee0a79d..22a48515c 100644
--- a/test/message_entities.cpp
+++ b/test/message_entities.cpp
@@ -1243,8 +1243,7 @@ TEST(MessageEntities, parse_html) {
   check_parse_html("🏟 🏟&lt;<abac aba>", "Unsupported start tag \"abac\" at byte offset 13");
   check_parse_html("🏟 🏟&lt;<abac>", "Unsupported start tag \"abac\" at byte offset 13");
   check_parse_html("🏟 🏟&lt;<i   =aba>", "Empty attribute name in the tag \"i\" at byte offset 13");
-  check_parse_html("🏟 🏟&lt;<i    aba>",
-                   "Expected equal sign in declaration of an attribute of the tag \"i\" at byte offset 13");
+  check_parse_html("🏟 🏟&lt;<i    aba>", "Can't find end tag corresponding to start tag \"i\"");
   check_parse_html("🏟 🏟&lt;<i    aba  =  ", "Unclosed start tag \"i\" at byte offset 13");
   check_parse_html("🏟 🏟&lt;<i    aba  =  190azAz-.,", "Unexpected end of name token at byte offset 27");
   check_parse_html("🏟 🏟&lt;<i    aba  =  \"&lt;&gt;&quot;>", "Unclosed start tag at byte offset 13");
@@ -1352,8 +1351,14 @@ TEST(MessageEntities, parse_html) {
   check_parse_html("🏟 🏟<b aba   =   caba><tg-emoji emoji-id=\"1\">🏟</tg-emoji>1</b>", "🏟 🏟🏟1",
                    {{td::MessageEntity::Type::Bold, 5, 3},
                     {td::MessageEntity::Type::CustomEmoji, 5, 2, td::CustomEmojiId(static_cast<td::int64>(1))}});
-  check_parse_html("<blockquote   cite=\"\">a&lt;<pre  >b;</></>", "a<b;",
+  check_parse_html("<blockquote   cite=\"\" askdlbas nasjdbaj nj12b3>a&lt;<pre  >b;</></>", "a<b;",
                    {{td::MessageEntity::Type::BlockQuote, 0, 4}, {td::MessageEntity::Type::Pre, 2, 2}});
+  check_parse_html("<blockquote   expandable>a&lt;<pre  >b;</></>", "a<b;",
+                   {{td::MessageEntity::Type::ExpandableBlockQuote, 0, 4}, {td::MessageEntity::Type::Pre, 2, 2}});
+  check_parse_html("<blockquote   expandable   asd>a&lt;<pre  >b;</></>", "a<b;",
+                   {{td::MessageEntity::Type::ExpandableBlockQuote, 0, 4}, {td::MessageEntity::Type::Pre, 2, 2}});
+  check_parse_html("<blockquote   expandable=false>a&lt;<pre  >b;</></>", "a<b;",
+                   {{td::MessageEntity::Type::ExpandableBlockQuote, 0, 4}, {td::MessageEntity::Type::Pre, 2, 2}});
 }
 
 static void check_parse_markdown(td::string text, const td::string &result,