[Embedder API] Introduce new update semantics callback

Author: loic-sharma

shell/platform/common/accessibility_bridge.cc

@@ -36,11 +36,26 @@ AccessibilityBridge::~AccessibilityBridge() {
   tree_->RemoveObserver(static_cast<ui::AXTreeObserver*>(this));
 }
 
+void AccessibilityBridge::AddFlutterSemanticsNodeUpdate(
+    const FlutterSemanticsNode2* node) {
+  pending_semantics_node_updates_[node->id] = FromFlutterSemanticsNode(node);
+}
+
+void AccessibilityBridge::AddFlutterSemanticsCustomActionUpdate(
+    const FlutterSemanticsCustomAction2* action) {
+  pending_semantics_custom_action_updates_[action->id] =
+      FromFlutterSemanticsCustomAction(action);
+}
+
+// TODO(loicsharma): Remove this as FlutterSemanticsNode is deprecated.
+// See: https://github.com/flutter/flutter/issues/121176
 void AccessibilityBridge::AddFlutterSemanticsNodeUpdate(
     const FlutterSemanticsNode* node) {
   pending_semantics_node_updates_[node->id] = FromFlutterSemanticsNode(node);
 }
 
+// TODO(loicsharma): Remove this as FlutterSemanticsNode is deprecated.
+// See: https://github.com/flutter/flutter/issues/121176
 void AccessibilityBridge::AddFlutterSemanticsCustomActionUpdate(
     const FlutterSemanticsCustomAction* action) {
   pending_semantics_custom_action_updates_[action->id] =
@@ -576,6 +591,74 @@ void AccessibilityBridge::SetTreeData(const SemanticsNode& node,
   }
 }
 
+AccessibilityBridge::SemanticsNode
+AccessibilityBridge::FromFlutterSemanticsNode(
+    const FlutterSemanticsNode2* flutter_node) {
+  SemanticsNode result;
+  result.id = flutter_node->id;
+  result.flags = flutter_node->flags;
+  result.actions = flutter_node->actions;
+  result.text_selection_base = flutter_node->text_selection_base;
+  result.text_selection_extent = flutter_node->text_selection_extent;
+  result.scroll_child_count = flutter_node->scroll_child_count;
+  result.scroll_index = flutter_node->scroll_index;
+  result.scroll_position = flutter_node->scroll_position;
+  result.scroll_extent_max = flutter_node->scroll_extent_max;
+  result.scroll_extent_min = flutter_node->scroll_extent_min;
+  result.elevation = flutter_node->elevation;
+  result.thickness = flutter_node->thickness;
+  if (flutter_node->label) {
+    result.label = std::string(flutter_node->label);
+  }
+  if (flutter_node->hint) {
+    result.hint = std::string(flutter_node->hint);
+  }
+  if (flutter_node->value) {
+    result.value = std::string(flutter_node->value);
+  }
+  if (flutter_node->increased_value) {
+    result.increased_value = std::string(flutter_node->increased_value);
+  }
+  if (flutter_node->decreased_value) {
+    result.decreased_value = std::string(flutter_node->decreased_value);
+  }
+  if (flutter_node->tooltip) {
+    result.tooltip = std::string(flutter_node->tooltip);
+  }
+  result.text_direction = flutter_node->text_direction;
+  result.rect = flutter_node->rect;
+  result.transform = flutter_node->transform;
+  if (flutter_node->child_count > 0) {
+    result.children_in_traversal_order = std::vector<int32_t>(
+        flutter_node->children_in_traversal_order,
+        flutter_node->children_in_traversal_order + flutter_node->child_count);
+  }
+  if (flutter_node->custom_accessibility_actions_count > 0) {
+    result.custom_accessibility_actions = std::vector<int32_t>(
+        flutter_node->custom_accessibility_actions,
+        flutter_node->custom_accessibility_actions +
+            flutter_node->custom_accessibility_actions_count);
+  }
+  return result;
+}
+
+AccessibilityBridge::SemanticsCustomAction
+AccessibilityBridge::FromFlutterSemanticsCustomAction(
+    const FlutterSemanticsCustomAction2* flutter_custom_action) {
+  SemanticsCustomAction result;
+  result.id = flutter_custom_action->id;
+  result.override_action = flutter_custom_action->override_action;
+  if (flutter_custom_action->label) {
+    result.label = std::string(flutter_custom_action->label);
+  }
+  if (flutter_custom_action->hint) {
+    result.hint = std::string(flutter_custom_action->hint);
+  }
+  return result;
+}
+
+// TODO(loicsharma): Remove this as FlutterSemanticsNode is deprecated.
+// See: https://github.com/flutter/flutter/issues/121176
 AccessibilityBridge::SemanticsNode
 AccessibilityBridge::FromFlutterSemanticsNode(
     const FlutterSemanticsNode* flutter_node) {
@@ -627,6 +710,9 @@ AccessibilityBridge::FromFlutterSemanticsNode(
   return result;
 }
 
+// TODO(loicsharma): Remove this as FlutterSemanticsCustomAction is
+// deprecated.
+// See: https://github.com/flutter/flutter/issues/121176
 AccessibilityBridge::SemanticsCustomAction
 AccessibilityBridge::FromFlutterSemanticsCustomAction(
     const FlutterSemanticsCustomAction* flutter_custom_action) {

shell/platform/common/accessibility_bridge.h

@@ -61,6 +61,27 @@ class AccessibilityBridge
   ///             To flush the pending updates, call the CommitUpdates().
   ///
   /// @param[in]  node           A pointer to the semantics node update.
+  void AddFlutterSemanticsNodeUpdate(const FlutterSemanticsNode2* node);
+
+  //------------------------------------------------------------------------------
+  /// @brief      Adds a custom semantics action update to the pending semantics
+  ///             update. Calling this method alone will NOT update the
+  ///             semantics tree. To flush the pending updates, call the
+  ///             CommitUpdates().
+  ///
+  /// @param[in]  action           A pointer to the custom semantics action
+  ///                              update.
+  void AddFlutterSemanticsCustomActionUpdate(
+      const FlutterSemanticsCustomAction2* action);
+
+  //------------------------------------------------------------------------------
+  /// @brief      Adds a semantics node update to the pending semantics update.
+  ///             Calling this method alone will NOT update the semantics tree.
+  ///             To flush the pending updates, call the CommitUpdates().
+  ///
+  /// @param[in]  node           A pointer to the semantics node update.
+  //  TODO(loicsharma): Remove this as FlutterSemanticsNode is deprecated.
+  //  See: https://github.com/flutter/flutter/issues/121176
   void AddFlutterSemanticsNodeUpdate(const FlutterSemanticsNode* node);
 
   //------------------------------------------------------------------------------
@@ -71,6 +92,9 @@ class AccessibilityBridge
   ///
   /// @param[in]  action           A pointer to the custom semantics action
   ///                              update.
+  //  TODO(loicsharma): Remove this as FlutterSemanticsCustomAction is
+  //  deprecated.
+  //  See: https://github.com/flutter/flutter/issues/121176
   void AddFlutterSemanticsCustomActionUpdate(
       const FlutterSemanticsCustomAction* action);
 
@@ -251,8 +275,19 @@ class AccessibilityBridge
   void SetTooltipFromFlutterUpdate(ui::AXNodeData& node_data,
                                    const SemanticsNode& node);
   void SetTreeData(const SemanticsNode& node, ui::AXTreeUpdate& tree_update);
+  SemanticsNode FromFlutterSemanticsNode(
+      const FlutterSemanticsNode2* flutter_node);
+  SemanticsCustomAction FromFlutterSemanticsCustomAction(
+      const FlutterSemanticsCustomAction2* flutter_custom_action);
+
+  // TODO(loicsharma): Remove this as FlutterSemanticsNode is deprecated.
+  // See: https://github.com/flutter/flutter/issues/121176
   SemanticsNode FromFlutterSemanticsNode(
       const FlutterSemanticsNode* flutter_node);
+
+  // TODO(loicsharma): Remove this as FlutterSemanticsCustomAction is
+  // deprecated.
+  // See: https://github.com/flutter/flutter/issues/121176
   SemanticsCustomAction FromFlutterSemanticsCustomAction(
       const FlutterSemanticsCustomAction* flutter_custom_action);
 

shell/platform/embedder/embedder.cc

@@ -1268,10 +1268,10 @@ FlutterSemanticsNode CreateEmbedderSemanticsNode(
       transform.get(SkMatrix::kMScaleY), transform.get(SkMatrix::kMTransY),
       transform.get(SkMatrix::kMPersp0), transform.get(SkMatrix::kMPersp1),
       transform.get(SkMatrix::kMPersp2)};
+
   // Do not add new members to FlutterSemanticsNode.
   // This would break the forward compatibility of FlutterSemanticsUpdate.
-  // TODO(loicsharma): Introduce FlutterSemanticsNode2.
-  // https://github.com/flutter/flutter/issues/121176
+  // All new members must be added to FlutterSemanticsNode2 instead.
   return {
       sizeof(FlutterSemanticsNode),
       node.id,
@@ -1305,14 +1305,56 @@ FlutterSemanticsNode CreateEmbedderSemanticsNode(
   };
 }
 
+// Translates engine semantic nodes to embedder semantic nodes.
+FlutterSemanticsNode2 CreateEmbedderSemanticsNode2(
+    const flutter::SemanticsNode& node) {
+  SkMatrix transform = node.transform.asM33();
+  FlutterTransformation flutter_transform{
+      transform.get(SkMatrix::kMScaleX), transform.get(SkMatrix::kMSkewX),
+      transform.get(SkMatrix::kMTransX), transform.get(SkMatrix::kMSkewY),
+      transform.get(SkMatrix::kMScaleY), transform.get(SkMatrix::kMTransY),
+      transform.get(SkMatrix::kMPersp0), transform.get(SkMatrix::kMPersp1),
+      transform.get(SkMatrix::kMPersp2)};
+  return {
+      sizeof(FlutterSemanticsNode2),
+      node.id,
+      static_cast<FlutterSemanticsFlag>(node.flags),
+      static_cast<FlutterSemanticsAction>(node.actions),
+      node.textSelectionBase,
+      node.textSelectionExtent,
+      node.scrollChildren,
+      node.scrollIndex,
+      node.scrollPosition,
+      node.scrollExtentMax,
+      node.scrollExtentMin,
+      node.elevation,
+      node.thickness,
+      node.label.c_str(),
+      node.hint.c_str(),
+      node.value.c_str(),
+      node.increasedValue.c_str(),
+      node.decreasedValue.c_str(),
+      static_cast<FlutterTextDirection>(node.textDirection),
+      FlutterRect{node.rect.fLeft, node.rect.fTop, node.rect.fRight,
+                  node.rect.fBottom},
+      flutter_transform,
+      node.childrenInTraversalOrder.size(),
+      node.childrenInTraversalOrder.data(),
+      node.childrenInHitTestOrder.data(),
+      node.customAccessibilityActions.size(),
+      node.customAccessibilityActions.data(),
+      node.platformViewId,
+      node.tooltip.c_str(),
+  };
+}
+
 // Translates engine semantic custom actions to embedder semantic custom
 // actions.
 FlutterSemanticsCustomAction CreateEmbedderSemanticsCustomAction(
     const flutter::CustomAccessibilityAction& action) {
   // Do not add new members to FlutterSemanticsCustomAction.
   // This would break the forward compatibility of FlutterSemanticsUpdate.
-  // TODO(loicsharma): Introduce FlutterSemanticsCustomAction2.
-  // https://github.com/flutter/flutter/issues/121176
+  // All new members must be added to FlutterSemanticsCustomAction2 instead.
   return {
       sizeof(FlutterSemanticsCustomAction),
       action.id,
@@ -1322,8 +1364,21 @@ FlutterSemanticsCustomAction CreateEmbedderSemanticsCustomAction(
   };
 }
 
+// Translates engine semantic custom actions to embedder semantic custom
+// actions.
+FlutterSemanticsCustomAction2 CreateEmbedderSemanticsCustomAction2(
+    const flutter::CustomAccessibilityAction& action) {
+  return {
+      sizeof(FlutterSemanticsCustomAction2),
+      action.id,
+      static_cast<FlutterSemanticsAction>(action.overrideId),
+      action.label.c_str(),
+      action.hint.c_str(),
+  };
+}
+
 // Create a callback to notify the embedder of semantic updates
-// using the new embedder callback 'update_semantics_callback'.
+// using the deprecated embedder callback 'update_semantics_callback'.
 flutter::PlatformViewEmbedder::UpdateSemanticsCallback
 CreateNewEmbedderSemanticsUpdateCallback(
     FlutterUpdateSemanticsCallback update_semantics_callback,
@@ -1354,6 +1409,54 @@ CreateNewEmbedderSemanticsUpdateCallback(
   };
 }
 
+// Create a callback to notify the embedder of semantic updates
+// using the new embedder callback 'update_semantics_callback2'.
+flutter::PlatformViewEmbedder::UpdateSemanticsCallback
+CreateNewEmbedderSemanticsUpdateCallback2(
+    FlutterUpdateSemanticsCallback2 update_semantics_callback,
+    void* user_data) {
+  return [update_semantics_callback, user_data](
+             const flutter::SemanticsNodeUpdates& nodes,
+             const flutter::CustomAccessibilityActionUpdates& actions) {
+    std::vector<FlutterSemanticsNode2> embedder_nodes;
+    for (const auto& value : nodes) {
+      embedder_nodes.push_back(CreateEmbedderSemanticsNode2(value.second));
+    }
+
+    std::vector<FlutterSemanticsCustomAction2> embedder_custom_actions;
+    for (const auto& value : actions) {
+      embedder_custom_actions.push_back(
+          CreateEmbedderSemanticsCustomAction2(value.second));
+    }
+
+    // Provide the embedder an array of pointers to maintain full forward and
+    // backward compatibility even if new members are added to semantic structs.
+    std::vector<FlutterSemanticsNode2*> embedder_node_pointers;
+    std::vector<FlutterSemanticsCustomAction2*> embedder_custom_action_pointers;
+
+    embedder_node_pointers.reserve(embedder_nodes.size());
+    embedder_custom_action_pointers.reserve(embedder_custom_actions.size());
+
+    for (auto& node : embedder_nodes) {
+      embedder_node_pointers.push_back(&node);
+    }
+
+    for (auto& action : embedder_custom_actions) {
+      embedder_custom_action_pointers.push_back(&action);
+    }
+
+    FlutterSemanticsUpdate2 update{
+        .struct_size = sizeof(FlutterSemanticsUpdate2),
+        .nodes_count = embedder_node_pointers.size(),
+        .nodes = embedder_node_pointers.data(),
+        .custom_actions_count = embedder_custom_action_pointers.size(),
+        .custom_actions = embedder_custom_action_pointers.data(),
+    };
+
+    update_semantics_callback(&update, user_data);
+  };
+}
+
 // Create a callback to notify the embedder of semantic updates
 // using the legacy embedder callbacks 'update_semantics_node_callback' and
 // 'update_semantics_custom_action_callback'.
@@ -1413,6 +1516,11 @@ CreateEmbedderSemanticsUpdateCallback(const FlutterProjectArgs* args,
   // The embedder can register the new callback, or the legacy callbacks, or
   // nothing at all. Handle the case where the embedder registered the 'new'
   // callback.
+  if (SAFE_ACCESS(args, update_semantics_callback2, nullptr) != nullptr) {
+    return CreateNewEmbedderSemanticsUpdateCallback2(
+        args->update_semantics_callback2, user_data);
+  }
+
   if (SAFE_ACCESS(args, update_semantics_callback, nullptr) != nullptr) {
     return CreateNewEmbedderSemanticsUpdateCallback(
         args->update_semantics_callback, user_data);
@@ -1590,15 +1698,27 @@ FlutterEngineResult FlutterEngineInitialize(size_t version,
     settings.log_tag = SAFE_ACCESS(args, log_tag, nullptr);
   }
 
-  if (args->update_semantics_callback != nullptr &&
-      (args->update_semantics_node_callback != nullptr ||
-       args->update_semantics_custom_action_callback != nullptr)) {
+  bool has_update_semantics_2_callback =
+      SAFE_ACCESS(args, update_semantics_callback2, nullptr) != nullptr;
+  bool has_update_semantics_callback =
+      SAFE_ACCESS(args, update_semantics_callback, nullptr) != nullptr;
+  bool has_legacy_update_semantics_callback =
+      SAFE_ACCESS(args, update_semantics_node_callback, nullptr) != nullptr ||
+      SAFE_ACCESS(args, update_semantics_custom_action_callback, nullptr) !=
+          nullptr;
+
+  int semantic_callback_count = (has_update_semantics_2_callback ? 1 : 0) +
+                                (has_update_semantics_callback ? 1 : 0) +
+                                (has_legacy_update_semantics_callback ? 1 : 0);
+
+  if (semantic_callback_count > 1) {
     return LOG_EMBEDDER_ERROR(
         kInvalidArguments,
         "Multiple semantics update callbacks provided. "
-        "Embedders should provide either `update_semantics_callback` "
-        "or both `update_semantics_nodes_callback` and "
-        "`update_semantics_custom_actions_callback`.");
+        "Embedders should provide either `update_semantics_callback2`, "
+        "`update_semantics_callback`, or both "
+        "`update_semantics_node_callback` and "
+        "`update_semantics_custom_action_callback`.");
   }
 
   flutter::PlatformViewEmbedder::UpdateSemanticsCallback