feat: add ability to limit message snapshot size (#6602)

Reviewed-by: pajlada <rasmus.karlsson@pajlada.com>

src/common/Channel.cpp

@@ -71,11 +71,17 @@ bool Channel::hasMessages() const
     return !this->messages_.empty();
 }
 
-LimitedQueueSnapshot<MessagePtr> Channel::getMessageSnapshot()
+LimitedQueueSnapshot<MessagePtr> Channel::getMessageSnapshot() const
 {
     return this->messages_.getSnapshot();
 }
 
+LimitedQueueSnapshot<MessagePtr> Channel::getMessageSnapshot(
+    size_t nItems) const
+{
+    return this->messages_.lastN(nItems);
+}
+
 void Channel::addMessage(MessagePtr message, MessageContext context,
                          std::optional<MessageFlags> overridingFlags)
 {
@@ -117,7 +123,7 @@ void Channel::addSystemMessage(const QString &contents)
 void Channel::addOrReplaceTimeout(MessagePtr message, const QDateTime &now)
 {
     addOrReplaceChannelTimeout(
-        this->getMessageSnapshot(), std::move(message), now,
+        this->getMessageSnapshot(20), std::move(message), now,
         [this](auto /*idx*/, auto msg, auto replacement) {
             this->replaceMessage(msg, replacement);
         },
@@ -130,7 +136,7 @@ void Channel::addOrReplaceTimeout(MessagePtr message, const QDateTime &now)
 void Channel::addOrReplaceClearChat(MessagePtr message, const QDateTime &now)
 {
     addOrReplaceChannelClear(
-        this->getMessageSnapshot(), std::move(message), now,
+        this->getMessageSnapshot(20), std::move(message), now,
         [this](auto /*idx*/, auto msg, auto replacement) {
             this->replaceMessage(msg, replacement);
         },

src/common/Channel.hpp

@@ -79,7 +79,8 @@ public:
     virtual const QString &getLocalizedName() const;
     bool isTwitchChannel() const;
     virtual bool isEmpty() const;
-    LimitedQueueSnapshot<MessagePtr> getMessageSnapshot();
+    LimitedQueueSnapshot<MessagePtr> getMessageSnapshot() const;
+    LimitedQueueSnapshot<MessagePtr> getMessageSnapshot(size_t nItems) const;
 
     // MESSAGES
     // overridingFlags can be filled in with flags that should be used instead