[engine] Add Flutter 3.3 headers and sources

Author: swift-kim

flutter/shell/platform/common/accessibility_bridge.cc

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_ACCESSIBILITY_BRIDGE_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_ACCESSIBILITY_BRIDGE_H_
+
+#include <unordered_map>
+
+#include "flutter/fml/mapping.h"
+#include "flutter/shell/platform/embedder/embedder.h"
+
+#include "flutter/third_party/accessibility/ax/ax_event_generator.h"
+#include "flutter/third_party/accessibility/ax/ax_tree.h"
+#include "flutter/third_party/accessibility/ax/ax_tree_observer.h"
+#include "flutter/third_party/accessibility/ax/platform/ax_platform_node_delegate.h"
+
+#include "flutter_platform_node_delegate.h"
+
+namespace flutter {
+
+//------------------------------------------------------------------------------
+/// Use this class to maintain an accessibility tree. This class consumes
+/// semantics updates from the embedder API and produces an accessibility tree
+/// in the native format.
+///
+/// The bridge creates an AXTree to hold the semantics data that comes from
+/// Flutter semantics updates. The tree holds AXNode[s] which contain the
+/// semantics information for semantics node. The AXTree resemble the Flutter
+/// semantics tree in the Flutter framework. The bridge also uses
+/// FlutterPlatformNodeDelegate to wrap each AXNode in order to provide
+/// an accessibility tree in the native format.
+///
+/// This class takes in a AccessibilityBridgeDelegate instance and is in charge
+/// of its lifecycle. The delegate are used to handle the accessibility events
+/// and actions.
+///
+/// To use this class, you must provide your own implementation of
+/// FlutterPlatformNodeDelegate and AccessibilityBridgeDelegate.
+class AccessibilityBridge
+    : public std::enable_shared_from_this<AccessibilityBridge>,
+      public FlutterPlatformNodeDelegate::OwnerBridge,
+      private ui::AXTreeObserver {
+ public:
+  //-----------------------------------------------------------------------------
+  /// Delegate to handle requests from the accessibility bridge. The requests
+  /// include sending accessibility event to native accessibility system,
+  /// routing accessibility action to the Flutter framework, and creating
+  /// platform specific FlutterPlatformNodeDelegate.
+  ///
+  /// The accessibility events are generated when accessibility tree changes.
+  /// These events must be sent to the native accessibility system through
+  /// the native API for the system to pick up the changes
+  /// (e.g. NSAccessibilityPostNotification in MacOS).
+  ///
+  /// The accessibility actions are generated by the native accessibility system
+  /// when users interacted with the assistive technologies. Those actions
+  /// needed to be sent to the Flutter framework.
+  ///
+  /// Each platform needs to implement the FlutterPlatformNodeDelegate and
+  /// returns its platform specific instance of FlutterPlatformNodeDelegate
+  /// in this delegate.
+  class AccessibilityBridgeDelegate {
+   public:
+    virtual ~AccessibilityBridgeDelegate() = default;
+    //---------------------------------------------------------------------------
+    /// @brief      Handle accessibility events generated due to accessibility
+    ///             tree changes. These events are generated in accessibility
+    ///             bridge and needed to be sent to native accessibility system.
+    ///             See ui::AXEventGenerator::Event for possible events.
+    ///
+    /// @param[in]  targeted_event      The object that contains both the
+    ///                                 generated event and the event target.
+    virtual void OnAccessibilityEvent(
+        ui::AXEventGenerator::TargetedEvent targeted_event) = 0;
+
+    //---------------------------------------------------------------------------
+    /// @brief      Dispatch accessibility action back to the Flutter framework.
+    ///             These actions are generated in the native accessibility
+    ///             system when users interact with the assistive technologies.
+    ///             For example, a
+    ///             FlutterSemanticsAction::kFlutterSemanticsActionTap is
+    ///             fired when user click or touch the screen.
+    ///
+    /// @param[in]  target              The semantics node id of the action
+    ///                                 target.
+    /// @param[in]  action              The generated flutter semantics action.
+    /// @param[in]  data                Additional data associated with the
+    ///                                 action.
+    virtual void DispatchAccessibilityAction(AccessibilityNodeId target,
+                                             FlutterSemanticsAction action,
+                                             fml::MallocMapping data) = 0;
+
+    //---------------------------------------------------------------------------
+    /// @brief      Creates a platform specific FlutterPlatformNodeDelegate.
+    ///             Ownership passes to the caller. This method will be called
+    ///             by accessibility bridge whenever a new AXNode is created in
+    ///             AXTree. Each platform needs to implement this method in
+    ///             order to inject its subclass into the accessibility bridge.
+    virtual std::shared_ptr<FlutterPlatformNodeDelegate>
+    CreateFlutterPlatformNodeDelegate() = 0;
+  };
+
+  //-----------------------------------------------------------------------------
+  /// @brief      Creates a new instance of a accessibility bridge.
+  ///
+  /// @param[in]  user_data           A custom pointer to the data of your
+  ///                                 choice. This pointer can be retrieve later
+  ///                                 through GetUserData().
+  explicit AccessibilityBridge(
+      std::unique_ptr<AccessibilityBridgeDelegate> delegate);
+  ~AccessibilityBridge();
+
+  //-----------------------------------------------------------------------------
+  /// @brief      The ID of the root node in the accessibility tree. In Flutter,
+  //              this is always 0.
+  static constexpr int32_t kRootNodeId = 0;
+
+  //------------------------------------------------------------------------------
+  /// @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.
+  void AddFlutterSemanticsNodeUpdate(const FlutterSemanticsNode* 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 FlutterSemanticsCustomAction* action);
+
+  //------------------------------------------------------------------------------
+  /// @brief      Flushes the pending updates and applies them to this
+  ///             accessibility bridge. Calling this with no pending updates
+  ///             does nothing, and callers should call this method at the end
+  ///             of an atomic batch to avoid leaving the tree in a unstable
+  ///             state. For example if a node reparents from A to B, callers
+  ///             should only call this method when both removal from A and
+  ///             addition to B are in the pending updates.
+  void CommitUpdates();
+
+  //------------------------------------------------------------------------------
+  /// @brief      Get the flutter platform node delegate with the given id from
+  ///             this accessibility bridge. Returns expired weak_ptr if the
+  ///             delegate associated with the id does not exist or has been
+  ///             removed from the accessibility tree.
+  ///
+  /// @param[in]  id           The id of the flutter accessibility node you want
+  ///                          to retrieve.
+  std::weak_ptr<FlutterPlatformNodeDelegate>
+  GetFlutterPlatformNodeDelegateFromID(AccessibilityNodeId id) const;
+
+  //------------------------------------------------------------------------------
+  /// @brief      Get the ax tree data from this accessibility bridge. The tree
+  ///             data contains information such as the id of the node that
+  ///             has the keyboard focus or the text selection range.
+  const ui::AXTreeData& GetAXTreeData() const;
+
+  //------------------------------------------------------------------------------
+  /// @brief      Gets all pending accessibility events generated during
+  ///             semantics updates. This is useful when deciding how to handle
+  ///             events in AccessibilityBridgeDelegate::OnAccessibilityEvent in
+  ///             case one may decide to handle an event differently based on
+  ///             all pending events.
+  const std::vector<ui::AXEventGenerator::TargetedEvent> GetPendingEvents();
+
+  //------------------------------------------------------------------------------
+  /// @brief      Update the AccessibilityBridgeDelegate stored in the
+  ///             accessibility bridge to a new one.
+  void UpdateDelegate(std::unique_ptr<AccessibilityBridgeDelegate> delegate);
+
+ private:
+  // See FlutterSemanticsNode in embedder.h
+  typedef struct {
+    int32_t id;
+    FlutterSemanticsFlag flags;
+    FlutterSemanticsAction actions;
+    int32_t text_selection_base;
+    int32_t text_selection_extent;
+    int32_t scroll_child_count;
+    int32_t scroll_index;
+    double scroll_position;
+    double scroll_extent_max;
+    double scroll_extent_min;
+    double elevation;
+    double thickness;
+    std::string label;
+    std::string hint;
+    std::string value;
+    std::string increased_value;
+    std::string decreased_value;
+    FlutterTextDirection text_direction;
+    FlutterRect rect;
+    FlutterTransformation transform;
+    std::vector<int32_t> children_in_traversal_order;
+    std::vector<int32_t> custom_accessibility_actions;
+  } SemanticsNode;
+
+  // See FlutterSemanticsCustomAction in embedder.h
+  typedef struct {
+    int32_t id;
+    FlutterSemanticsAction override_action;
+    std::string label;
+    std::string hint;
+  } SemanticsCustomAction;
+
+  std::unordered_map<AccessibilityNodeId,
+                     std::shared_ptr<FlutterPlatformNodeDelegate>>
+      id_wrapper_map_;
+  ui::AXTree tree_;
+  ui::AXEventGenerator event_generator_;
+  std::unordered_map<int32_t, SemanticsNode> pending_semantics_node_updates_;
+  std::unordered_map<int32_t, SemanticsCustomAction>
+      pending_semantics_custom_action_updates_;
+  AccessibilityNodeId last_focused_id_ = ui::AXNode::kInvalidAXID;
+  std::unique_ptr<AccessibilityBridgeDelegate> delegate_;
+
+  void InitAXTree(const ui::AXTreeUpdate& initial_state);
+  void GetSubTreeList(SemanticsNode target, std::vector<SemanticsNode>& result);
+  void ConvertFluterUpdate(const SemanticsNode& node,
+                           ui::AXTreeUpdate& tree_update);
+  void SetRoleFromFlutterUpdate(ui::AXNodeData& node_data,
+                                const SemanticsNode& node);
+  void SetStateFromFlutterUpdate(ui::AXNodeData& node_data,
+                                 const SemanticsNode& node);
+  void SetActionsFromFlutterUpdate(ui::AXNodeData& node_data,
+                                   const SemanticsNode& node);
+  void SetBooleanAttributesFromFlutterUpdate(ui::AXNodeData& node_data,
+                                             const SemanticsNode& node);
+  void SetIntAttributesFromFlutterUpdate(ui::AXNodeData& node_data,
+                                         const SemanticsNode& node);
+  void SetIntListAttributesFromFlutterUpdate(ui::AXNodeData& node_data,
+                                             const SemanticsNode& node);
+  void SetStringListAttributesFromFlutterUpdate(ui::AXNodeData& node_data,
+                                                const SemanticsNode& node);
+  void SetNameFromFlutterUpdate(ui::AXNodeData& node_data,
+                                const SemanticsNode& node);
+  void SetValueFromFlutterUpdate(ui::AXNodeData& node_data,
+                                 const SemanticsNode& node);
+  void SetTreeData(const SemanticsNode& node, ui::AXTreeUpdate& tree_update);
+  SemanticsNode FromFlutterSemanticsNode(
+      const FlutterSemanticsNode* flutter_node);
+  SemanticsCustomAction FromFlutterSemanticsCustomAction(
+      const FlutterSemanticsCustomAction* flutter_custom_action);
+
+  // |AXTreeObserver|
+  void OnNodeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override;
+
+  // |AXTreeObserver|
+  void OnSubtreeWillBeDeleted(ui::AXTree* tree, ui::AXNode* node) override;
+
+  // |AXTreeObserver|
+  void OnNodeCreated(ui::AXTree* tree, ui::AXNode* node) override;
+
+  // |AXTreeObserver|
+  void OnNodeDeleted(ui::AXTree* tree, AccessibilityNodeId node_id) override;
+
+  // |AXTreeObserver|
+  void OnNodeReparented(ui::AXTree* tree, ui::AXNode* node) override;
+
+  // |AXTreeObserver|
+  void OnRoleChanged(ui::AXTree* tree,
+                     ui::AXNode* node,
+                     ax::mojom::Role old_role,
+                     ax::mojom::Role new_role) override;
+
+  // |AXTreeObserver|
+  void OnAtomicUpdateFinished(
+      ui::AXTree* tree,
+      bool root_changed,
+      const std::vector<ui::AXTreeObserver::Change>& changes) override;
+
+  // |FlutterPlatformNodeDelegate::OwnerBridge|
+  void SetLastFocusedId(AccessibilityNodeId node_id) override;
+
+  // |FlutterPlatformNodeDelegate::OwnerBridge|
+  AccessibilityNodeId GetLastFocusedId() override;
+
+  // |FlutterPlatformNodeDelegate::OwnerBridge|
+  gfx::NativeViewAccessible GetNativeAccessibleFromId(
+      AccessibilityNodeId id) override;
+
+  // |FlutterPlatformNodeDelegate::OwnerBridge|
+  void DispatchAccessibilityAction(AccessibilityNodeId target,
+                                   FlutterSemanticsAction action,
+                                   fml::MallocMapping data) override;
+
+  // |FlutterPlatformNodeDelegate::OwnerBridge|
+  gfx::RectF RelativeToGlobalBounds(const ui::AXNode* node,
+                                    bool& offscreen,
+                                    bool clip_bounds) override;
+
+  BASE_DISALLOW_COPY_AND_ASSIGN(AccessibilityBridge);
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_ACCESSIBILITY_BRIDGE_H_

flutter/shell/platform/common/accessibility_bridge.h

@@ -0,0 +1,50 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_CLIENT_WRAPPER_BINARY_MESSENGER_IMPL_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_CLIENT_WRAPPER_BINARY_MESSENGER_IMPL_H_
+
+#include <flutter_messenger.h>
+
+#include <map>
+#include <string>
+
+#include "include/flutter/binary_messenger.h"
+
+namespace flutter {
+
+// Wrapper around a FlutterDesktopMessengerRef that implements the
+// BinaryMessenger API.
+class BinaryMessengerImpl : public BinaryMessenger {
+ public:
+  explicit BinaryMessengerImpl(FlutterDesktopMessengerRef core_messenger);
+
+  virtual ~BinaryMessengerImpl();
+
+  // Prevent copying.
+  BinaryMessengerImpl(BinaryMessengerImpl const&) = delete;
+  BinaryMessengerImpl& operator=(BinaryMessengerImpl const&) = delete;
+
+  // |flutter::BinaryMessenger|
+  void Send(const std::string& channel,
+            const uint8_t* message,
+            size_t message_size,
+            BinaryReply reply) const override;
+
+  // |flutter::BinaryMessenger|
+  void SetMessageHandler(const std::string& channel,
+                         BinaryMessageHandler handler) override;
+
+ private:
+  // Handle for interacting with the C API.
+  FlutterDesktopMessengerRef messenger_;
+
+  // A map from channel names to the BinaryMessageHandler that should be called
+  // for incoming messages on that channel.
+  std::map<std::string, BinaryMessageHandler> handlers_;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_CLIENT_WRAPPER_BINARY_MESSENGER_IMPL_H_