fix: take indices to messages as a hint (#5683)

src/messages/LimitedQueue.hpp

@@ -8,6 +8,7 @@
 #include <mutex>
 #include <optional>
 #include <shared_mutex>
+#include <utility>
 #include <vector>
 
 namespace chatterino {
@@ -212,9 +213,10 @@ public:
      *
      * @param[in] index the index of the item to replace
      * @param[in] replacement the item to put in place of the item at index
+     * @param[out] prev (optional) the item located at @a index before replacing
      * @return true if a replacement took place
      */
-    bool replaceItem(size_t index, const T &replacement)
+    bool replaceItem(size_t index, const T &replacement, T *prev = nullptr)
     {
         std::unique_lock lock(this->mutex_);
 
@@ -223,10 +225,46 @@ public:
             return false;
         }
 
-        this->buffer_[index] = replacement;
+        if (prev)
+        {
+            *prev = std::exchange(this->buffer_[index], replacement);
+        }
+        else
+        {
+            this->buffer_[index] = replacement;
+        }
         return true;
     }
 
+    /**
+     * @brief Replace the needle with the given item
+     *
+     * @param hint A hint on where the needle _might_ be
+     * @param[in] needle the item to search for
+     * @param[in] replacement the item to replace needle with
+     * @return the index of the replaced item, or -1 if no replacement took place
+     */
+    int replaceItem(size_t hint, const T &needle, const T &replacement)
+    {
+        std::unique_lock lock(this->mutex_);
+
+        if (hint < this->buffer_.size() && this->buffer_[hint] == needle)
+        {
+            this->buffer_[hint] = replacement;
+            return static_cast<int>(hint);
+        }
+
+        for (size_t i = 0; i < this->buffer_.size(); ++i)
+        {
+            if (this->buffer_[i] == needle)
+            {
+                this->buffer_[i] = replacement;
+                return static_cast<int>(i);
+            }
+        }
+        return -1;
+    }
+
     /**
      * @brief Inserts the given item before another item
      * 
@@ -315,6 +353,32 @@ public:
         return std::nullopt;
     }
 
+    /**
+     * @brief Find an item with a hint
+     *
+     * @param hint A hint on where the needle _might_ be
+     * @param predicate that will used to find the item
+     * @return the item and its index or none if it's not found
+     */
+    std::optional<std::pair<size_t, T>> find(size_t hint, auto &&predicate)
+    {
+        std::unique_lock lock(this->mutex_);
+
+        if (hint < this->buffer_.size() && predicate(this->buffer_[hint]))
+        {
+            return std::pair{hint, this->buffer_[hint]};
+        };
+
+        for (size_t i = 0; i < this->buffer_.size(); i++)
+        {
+            if (predicate(this->buffer_[i]))
+            {
+                return std::pair{i, this->buffer_[i]};
+            }
+        }
+        return std::nullopt;
+    }
+
     /**
      * @brief Returns the first item matching a predicate, checking in reverse
      *