From 22bfbd06af1d0257419a9c9e0f2e3b0ebff30ddb Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Sat, 28 Dec 2019 11:27:04 +1100
Subject: [PATCH] Redraw relevant clients after adding/removing highlighters

---
 src/client.cc   |  9 +++++----
 src/commands.cc | 29 +++++++++++++++++++++++------
 src/context.cc  |  4 +++-
 3 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/src/client.cc b/src/client.cc
index 2c84de6b..da178623 100644
--- a/src/client.cc
+++ b/src/client.cc
@@ -171,20 +171,21 @@ void Client::change_buffer(Buffer& buffer)
         close_buffer_reload_dialog();
 
     auto& client_manager = ClientManager::instance();
+    WindowAndSelections ws = client_manager.get_free_window(buffer);
+
     m_window->options().unregister_watcher(*this);
     m_window->set_client(nullptr);
-
-    WindowAndSelections ws = client_manager.get_free_window(buffer);
     client_manager.add_free_window(std::move(m_window),
                                    std::move(context().selections()));
+
     m_window = std::move(ws.window);
     m_window->set_client(this);
     m_window->options().register_watcher(*this);
-    m_ui->set_ui_options(m_window->options()["ui_options"].get<UserInterface::Options>());
-
     context().selections_write_only() = std::move(ws.selections);
     context().set_window(*m_window);
+
     m_window->set_dimensions(m_ui->dimensions());
+    m_ui->set_ui_options(m_window->options()["ui_options"].get<UserInterface::Options>());
 
     m_window->hooks().run_hook(Hook::WinDisplay, buffer.name(), context());
     force_redraw();
diff --git a/src/commands.cc b/src/commands.cc
index a0ac6777..21ee4d0b 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -900,6 +900,27 @@ Highlighter& get_highlighter(const Context& context, StringView path)
     return *root;
 }
 
+static void redraw_relevant_clients(Context& context, StringView highlighter_path)
+{
+    StringView scope{highlighter_path.begin(), find(highlighter_path, '/')};
+    if (scope == "window")
+        context.window().force_redraw();
+    else if (scope == "buffer" or prefix_match(scope, "buffer="))
+    {
+        auto& buffer = scope == "buffer" ? context.buffer() : BufferManager::instance().get_buffer(scope.substr(7_byte));
+        for (auto&& client : ClientManager::instance())
+        {
+            if (&client->context().buffer() == &buffer)
+                client->context().window().force_redraw();
+        }
+    }
+    else
+    {
+        for (auto&& client : ClientManager::instance())
+            client->context().window().force_redraw();
+    }
+}
+
 const CommandDesc add_highlighter_cmd = {
     "add-highlighter",
     "addhl",
@@ -948,9 +969,7 @@ const CommandDesc add_highlighter_cmd = {
         parent.add_child(name.empty() ? auto_name(parser.positionals_from(1)) : std::move(name),
                             it->value.factory(highlighter_params, &parent));
 
-        // TODO: better, this will fail if we touch scopes highlighters that impact multiple windows
-        if (context.has_window())
-            context.window().force_redraw();
+        redraw_relevant_clients(context, path);
     }
 };
 
@@ -973,9 +992,7 @@ const CommandDesc remove_highlighter_cmd = {
         if (sep_it == rev_path.end())
             return;
         get_highlighter(context, {path.begin(), sep_it.base()}).remove_child({sep_it.base(), path.end()});
-
-        if (context.has_window())
-            context.window().force_redraw();
+        redraw_relevant_clients(context, path);
     }
 };
 
diff --git a/src/context.cc b/src/context.cc
index 2a0822ec..07259c97 100644
--- a/src/context.cc
+++ b/src/context.cc
@@ -178,7 +178,6 @@ void Context::change_buffer(Buffer& buffer)
         m_last_buffer = contains(BufferManager::instance(), current) ? current : nullptr;
     }
 
-    m_window.reset();
     if (has_client())
     {
         client().info_hide();
@@ -186,7 +185,10 @@ void Context::change_buffer(Buffer& buffer)
         client().change_buffer(buffer);
     }
     else
+    {
+        m_window.reset();
         m_selections = SelectionList{buffer, Selection{}};
+    }
 
     if (has_input_handler())
         input_handler().reset_normal_mode();