1 files changed, 56 insertions, 18 deletions

diff --git a/src/ui/style/StyleRuleSet.cpp b/src/ui/style/StyleRuleSet.cpp
index 403fe114..24b88af9 100644
--- a/src/ui/style/StyleRuleSet.cpp
+++ b/src/ui/style/StyleRuleSet.cpp
@@ -1,17 +1,30 @@
 #include "cru/ui/style/StyleRuleSet.hpp"
 #include "cru/common/Event.hpp"
+#include "cru/ui/controls/Control.hpp"
 #include "gsl/gsl_assert"
 
 #include <unordered_set>
 
 namespace cru::ui::style {
+StyleRuleSet::StyleRuleSet(StyleRuleSet* parent) { SetParent(parent); }
+
+void StyleRuleSet::SetParent(StyleRuleSet* parent) {
+  if (parent == parent_) return;
+  parent_change_event_guard_.Reset();
+  parent_ = parent;
+  if (parent != nullptr) {
+    parent_change_event_guard_.Reset(parent->ChangeEvent()->AddSpyOnlyHandler(
+        [this] { this->RaiseChangeEvent(); }));
+  }
+  RaiseChangeEvent();
+}
+
 void StyleRuleSet::AddStyleRule(StyleRule rule, gsl::index index) {
   Expects(index >= 0 && index <= GetSize());
 
   rules_.insert(rules_.cbegin() + index, std::move(rule));
 
-  UpdateChangeListener();
-  UpdateStyle();
+  RaiseChangeEvent();
 }
 
 void StyleRuleSet::RemoveStyleRule(gsl::index index, gsl::index count) {
@@ -20,25 +33,48 @@ void StyleRuleSet::RemoveStyleRule(gsl::index index, gsl::index count) {
 
   rules_.erase(rules_.cbegin() + index, rules_.cbegin() + index + count);
 
-  UpdateChangeListener();
-  UpdateStyle();
+  RaiseChangeEvent();
 }
 
 void StyleRuleSet::Set(const StyleRuleSet& other) {
   rules_ = other.rules_;
-  UpdateChangeListener();
-  UpdateStyle();
+
+  RaiseChangeEvent();
+}
+
+StyleRuleSetBind::StyleRuleSetBind(controls::Control* control,
+                                   StyleRuleSet* ruleset)
+    : control_(control), ruleset_(ruleset) {
+  Expects(control);
+  Expects(ruleset);
+
+  ruleset->ChangeEvent()->AddSpyOnlyHandler([this] {
+    UpdateRuleSetChainCache();
+    UpdateChangeListener();
+    UpdateStyle();
+  });
 }
 
-void StyleRuleSet::UpdateChangeListener() {
-  if (control_ == nullptr) return;
+void StyleRuleSetBind::UpdateRuleSetChainCache() {
+  ruleset_chain_cache_.clear();
+  auto parent = ruleset_;
+  while (parent != nullptr) {
+    ruleset_chain_cache_.push_back(parent);
+    parent = parent->GetParent();
+  }
+}
 
+void StyleRuleSetBind::UpdateChangeListener() {
   guard_.Clear();
 
   std::unordered_set<IBaseEvent*> events;
-  for (const auto& rule : rules_) {
-    auto e = rule.GetCondition()->ChangeOn(control_);
-    events.insert(e.cbegin(), e.cend());
+
+  // ruleset order does not matter
+  for (auto ruleset : ruleset_chain_cache_) {
+    for (const auto& rule : ruleset->GetRules()) {
+      auto e = rule.GetCondition()->ChangeOn(control_);
+      events.insert(e.cbegin(), e.cend());
+    }
   }
 
   for (auto e : events) {
@@ -46,13 +82,15 @@ void StyleRuleSet::UpdateChangeListener() {
   }
 }
 
-void StyleRuleSet::UpdateStyle() {
-  if (control_ == nullptr) return;
-
-  for (const auto& rule : rules_) {
-    if (rule.GetCondition()->Judge(control_)) {
-      rule.GetStyler()->Apply(control_);
-    }
+void StyleRuleSetBind::UpdateStyle() {
+  // cache is parent last, but when calculate style, parent first, so iterate
+  // reverse.
+  for (auto iter = ruleset_chain_cache_.crbegin();
+       iter != ruleset_chain_cache_.crend(); ++iter) {
+    for (const auto& rule : (*iter)->GetRules())
+      if (rule.GetCondition()->Judge(control_)) {
+        rule.GetStyler()->Apply(control_);
+      }
   }
 }
 }  // namespace cru::ui::style