Add a new 'arrange-buffers' to let users change the order of the buflist

src/buffer_manager.cc

@@ -105,4 +105,29 @@ void BufferManager::clear_buffer_trash()
     m_buffer_trash.clear();
 }
 
+void BufferManager::arrange_buffers(ConstArrayView<String> first_ones)
+{
+    Vector<size_t> indices;
+    for (const auto& name : first_ones)
+    {
+        auto it = find_if(m_buffers, [&](auto& buf) { return buf->name() == name or buf->display_name() == name; });
+        if (it == m_buffers.end())
+            throw runtime_error{format("no such buffer '{}'", name)};
+        size_t index = it - m_buffers.begin();
+        if (contains(indices, index))
+            throw runtime_error{format("buffer '{}' appears more than once", name)};
+        indices.push_back(index);
+    }
+
+    BufferList res;
+    for (size_t index : indices)
+        res.push_back(std::move(m_buffers[index]));
+    for (auto& buf : m_buffers)
+    {
+        if (buf)
+            res.push_back(std::move(buf));
+    }
+    m_buffers = std::move(res);
+}
+
 }

src/buffer_manager.hh

@@ -30,6 +30,8 @@ public:
     Buffer* get_buffer_ifp(StringView name);
     Buffer& get_buffer(StringView name);
 
+    void arrange_buffers(ConstArrayView<String> first_ones);
+
     Buffer& get_first_buffer();
 
     void backup_modified_buffers();

src/commands.cc

@@ -923,6 +923,25 @@ static void redraw_relevant_clients(Context& context, StringView highlighter_pat
     }
 }
 
+const CommandDesc arrange_buffers_cmd = {
+    "arrange-buffers",
+    nullptr,
+    "arrange-buffers <buffer>...: reorder the buffers in the buffers list\n"
+    "    the named buffers will be moved to the front of the buffer list, in the order given\n"
+    "    buffers that do not appear in the parameters will remain at the end of the list, keeping their current order",
+    ParameterDesc{{}, ParameterDesc::Flags::None, 1},
+    CommandFlags::None,
+    CommandHelper{},
+    [](const Context& context, CompletionFlags flags, CommandParameters params, size_t, ByteCount cursor_pos)
+    {
+        return complete_buffer_name<false>(context, flags, params.back(), cursor_pos);
+    },
+    [](const ParametersParser& parser, Context&, const ShellContext&)
+    {
+        BufferManager::instance().arrange_buffers(parser.positionals_from(0));
+    }
+};
+
 const CommandDesc add_highlighter_cmd = {
     "add-highlighter",
     "addhl",
@@ -2606,6 +2625,7 @@ void register_commands()
     register_command(delete_buffer_cmd);
     register_command(force_delete_buffer_cmd);
     register_command(rename_buffer_cmd);
+    register_command(arrange_buffers_cmd);
     register_command(add_highlighter_cmd);
     register_command(remove_highlighter_cmd);
     register_command(add_hook_cmd);