refactor: move zero width replacement to a function (#5594)

src/providers/twitch/IrcMessageHandler.cpp

@@ -702,15 +702,8 @@ void IrcMessageHandler::handlePrivMessage(Communi::IrcPrivateMessage *message,
         }
     }
 
-    // This is for compatibility with older Chatterino versions. Twitch didn't use
-    // to allow ZERO WIDTH JOINER unicode character, so Chatterino used ESCAPE_TAG
-    // instead.
-    // See https://github.com/Chatterino/chatterino2/issues/3384 and
-    // https://mm2pl.github.io/emoji_rfc.pdf for more details
-    this->addMessage(
-        message, chan,
-        message->content().replace(COMBINED_FIXER, ZERO_WIDTH_JOINER),
-        twitchServer, false, message->isAction());
+    this->addMessage(message, chan, unescapeZeroWidthJoiner(message->content()),
+                     twitchServer, false, message->isAction());
 
     if (message->tags().contains(u"pinned-chat-paid-amount"_s))
     {
@@ -915,10 +908,9 @@ void IrcMessageHandler::handleWhisperMessage(Communi::IrcMessage *ircMessage)
 
     auto *c = getApp()->getTwitch()->getWhispersChannel().get();
 
-    MessageBuilder builder(
-        c, ircMessage, args,
-        ircMessage->parameter(1).replace(COMBINED_FIXER, ZERO_WIDTH_JOINER),
-        false);
+    MessageBuilder builder(c, ircMessage, args,
+                           unescapeZeroWidthJoiner(ircMessage->parameter(1)),
+                           false);
 
     if (builder.isIgnored())
     {

src/providers/twitch/TwitchChannel.hpp

@@ -27,24 +27,6 @@
 
 namespace chatterino {
 
-// This is for compatibility with older Chatterino versions. Twitch didn't use
-// to allow ZERO WIDTH JOINER unicode character, so Chatterino used ESCAPE_TAG
-// instead.
-// See https://github.com/Chatterino/chatterino2/issues/3384 and
-// https://mm2pl.github.io/emoji_rfc.pdf for more details
-const QString ZERO_WIDTH_JOINER = QString(QChar(0x200D));
-
-// Here be MSVC: Do NOT replace with "\U" literal, it will fail silently.
-namespace {
-    const QChar ESCAPE_TAG_CHARS[2] = {QChar::highSurrogate(0xE0002),
-                                       QChar::lowSurrogate(0xE0002)};
-}
-const QString ESCAPE_TAG = QString(ESCAPE_TAG_CHARS, 2);
-
-const static QRegularExpression COMBINED_FIXER(
-    QString("(?<!%1)%1").arg(ESCAPE_TAG),
-    QRegularExpression::UseUnicodePropertiesOption);
-
 enum class HighlightState;
 
 struct Emote;