Store HistoryRegisters with most recent entry in front

Closes #3105

src/input_handler.cc

@@ -752,7 +752,7 @@ public:
           m_empty_text{std::move(emptystr)},
           m_line_editor{context().faces()}, m_flags(flags),
           m_history{RegisterManager::instance()[history_register]},
-          m_current_history{m_history.get(context()).size()},
+          m_current_history{-1},
           m_auto_complete{context().options()["autocomplete"].get<AutoComplete>() & AutoComplete::Prompt},
           m_idle_timer{TimePoint::max(), context().flags() & Context::Flags::Draft ?
                            Timer::Callback{} : [this](Timer&) {
@@ -861,48 +861,28 @@ public:
         }
         else if (key == Key::Up or key == ctrl('p'))
         {
-            if (m_current_history != 0)
+            auto history = m_history.get(context());
+            m_current_history = std::min(static_cast<int>(history.size()) - 1, m_current_history);
+            if (m_current_history == -1)
+               m_prefix = line;
+            auto next = find_if(history.subrange(m_current_history + 1), [this](StringView s) { return prefix_match(s, m_prefix); });
+            if (next != history.end())
             {
-                auto history = m_history.get(context());
+                m_current_history = next - history.begin();
-                // The history register might have been mutated in the mean time
+                m_line_editor.reset(*next, m_empty_text);
-                m_current_history = std::min(history.size(), m_current_history);
-                if (m_current_history == history.size())
-                   m_prefix = line;
-                auto index = m_current_history;
-                // search for the previous history entry matching typed prefix
-                do
-                {
-                    --index;
-                    if (prefix_match(history[index], m_prefix))
-                    {
-                        m_current_history = index;
-                        m_line_editor.reset(history[index], m_empty_text);
-                        break;
-                    }
-                } while (index != 0);
-
-                clear_completions();
-                m_refresh_completion_pending = true;
             }
+            clear_completions();
+            m_refresh_completion_pending = true;
         }
         else if (key == Key::Down or key == ctrl('n')) // next
         {
             auto history = m_history.get(context());
-            // The history register might have been mutated in the mean time
+            m_current_history = std::min(static_cast<int>(history.size()) - 1, m_current_history);
-            m_current_history = std::min(history.size(), m_current_history);
+            if (m_current_history >= 0)
-            if (m_current_history < history.size())
             {
-                // search for the next history entry matching typed prefix
+                auto next = find_if(history.subrange(0, m_current_history) | reverse(), [this](StringView s) { return prefix_match(s, m_prefix); });
-                ++m_current_history;
+                m_current_history = history.rend() - next - 1;
-                while (m_current_history != history.size() and
+                m_line_editor.reset(next != history.rend() ? *next : m_prefix, m_empty_text);
-                       not prefix_match(history[m_current_history], m_prefix))
-                    ++m_current_history;
-
-                if (m_current_history != history.size())
-                    m_line_editor.reset(history[m_current_history], m_empty_text);
-                else
-                    m_line_editor.reset(m_prefix, m_empty_text);
-
                 clear_completions();
                 m_refresh_completion_pending = true;
             }
@@ -1162,7 +1142,7 @@ private:
     bool           m_line_changed = false;
     PromptFlags    m_flags;
     Register&      m_history;
-    size_t         m_current_history;
+    int            m_current_history;
     bool           m_auto_complete;
     bool           m_refresh_completion_pending = true;
     Timer          m_idle_timer;

src/normal.cc

@@ -941,7 +941,7 @@ template<SelectMode mode, RegexMode regex_mode>
 void search_next(Context& context, NormalParams params)
 {
     const char reg = to_lower(params.reg ? params.reg : '/');
-    StringView str = RegisterManager::instance()[reg].get(context).back();
+    StringView str = RegisterManager::instance()[reg].get(context).front();
     if (not str.empty())
     {
         Regex regex{str, direction_flags(regex_mode)};

src/register_manager.cc

@@ -40,16 +40,14 @@ void HistoryRegister::set(Context& context, ConstArrayView<String> values, bool
         return;
     }
 
-    for (auto& entry : values)
+    for (auto&& entry : values | reverse()) 
     {
-        m_content.erase(std::remove(m_content.begin(), m_content.end(), entry),
+        m_content.erase(std::remove(m_content.begin(), m_content.end(), entry), m_content.end());
-                      m_content.end());
+        m_content.insert(m_content.begin(), entry);
-        m_content.push_back(entry);
     }
 
-    const size_t current_size = m_content.size();
+    if (m_content.size() > size_limit)
-    if (current_size > size_limit)
+        m_content.erase(m_content.end() - (m_content.size() - size_limit), m_content.end());
-        m_content.erase(m_content.begin(), m_content.begin() + (current_size - size_limit));
 
     if (not m_disable_modified_hook)
         context.hooks().run_hook(Hook::RegisterModified, m_name, context);
@@ -57,7 +55,7 @@ void HistoryRegister::set(Context& context, ConstArrayView<String> values, bool
 
 const String& HistoryRegister::get_main(const Context&, size_t)
 {
-    return m_content.empty() ? String::ms_empty : m_content.back();
+    return m_content.empty() ? String::ms_empty : m_content.front();
 }
 
 static const HashMap<String, Codepoint> reg_names = {