Redraw window when the face definition changed

Hash the current face state and store that hash to check for changes.

src/face.hh

@@ -44,6 +44,11 @@ constexpr bool operator!=(const Face& lhs, const Face& rhs)
     return not (lhs == rhs);
 }
 
+constexpr size_t hash_value(const Face& val)
+{
+    return hash_values(val.fg, val.bg, val.attributes);
+}
+
 constexpr Face merge_faces(const Face& base, const Face& face)
 {
     return face.attributes & Attribute::Exclusive ?

src/face_registry.hh

@@ -20,6 +20,13 @@ public:
     void add_face(StringView name, StringView facedesc, bool override = false);
     void remove_face(StringView name);
 
+    struct FaceOrAlias
+    {
+        Face face = {};
+        String alias = {};
+    };
+    using FaceMap = HashMap<String, FaceOrAlias, MemoryDomain::Faces>;
+
     auto flatten_faces() const
     {
         auto merge = [](auto&& first, const FaceMap& second) {
@@ -33,19 +40,11 @@ public:
         return merge(merge(grand_parent, parent), m_faces);
     }
 
-    struct FaceOrAlias
-    {
-        Face face = {};
-        String alias = {};
-    };
-
 private:
     friend class Scope;
     FaceRegistry();
 
     SafePtr<FaceRegistry> m_parent;
-
-    using FaceMap = HashMap<String, FaceOrAlias, MemoryDomain::Faces>;
     FaceMap m_faces;
 };
 

src/window.cc

@@ -75,6 +75,14 @@ void Window::center_column(ColumnCount buffer_column)
     display_column_at(buffer_column, m_dimensions.column/2_col);
 }
 
+static uint32_t compute_faces_hash(const FaceRegistry& faces)
+{
+    uint32_t hash = 0;
+    for (auto&& face : faces.flatten_faces() | transform(&FaceRegistry::FaceMap::Item::value))
+        hash = combine_hash(hash, face.alias.empty() ? hash_value(face.face) : hash_value(face.alias));
+    return hash;
+}
+
 Window::Setup Window::build_setup(const Context& context) const
 {
     Vector<BufferRange, MemoryDomain::Display> selections;
@@ -83,6 +91,7 @@ Window::Setup Window::build_setup(const Context& context) const
 
     return { m_position, m_dimensions,
              context.buffer().timestamp(),
+             compute_faces_hash(context.faces()),
              context.selections().main_index(),
              std::move(selections) };
 }
@@ -95,7 +104,8 @@ bool Window::needs_redraw(const Context& context) const
         m_dimensions != m_last_setup.dimensions or
         context.buffer().timestamp() != m_last_setup.timestamp or
         selections.main_index() != m_last_setup.main_selection or
-        selections.size() != m_last_setup.selections.size())
+        selections.size() != m_last_setup.selections.size() or
+        compute_faces_hash(context.faces()) != m_last_setup.faces_hash)
         return true;
 
     for (int i = 0; i < selections.size(); ++i)

src/window.hh

@@ -72,6 +72,7 @@ private:
         DisplayCoord position;
         DisplayCoord dimensions;
         size_t timestamp;
+        size_t faces_hash;
         size_t main_selection;
         Vector<BufferRange, MemoryDomain::Display> selections;
     };