Creates AXPosition to uniquely identify a position in the accessibility tree

content/browser/accessibility/browser_accessibility_cocoa.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <map>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/strings/string16.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/app/strings/grit/content_strings.h"
+#include "content/browser/accessibility/ax_platform_position.h"
 #include "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/accessibility/browser_accessibility_manager_mac.h"
 #include "content/browser/accessibility/one_shot_accessibility_tree_search.h"
 #include "content/public/common/content_client.h"
 #include "third_party/skia/include/core/SkColor.h"
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 using content::AXTreeIDRegistry;
 using content::AccessibilityMatchPredicate;
@@ skipping 58 matching lines @@
     @"AXTextMarkerRangeForUnorderedTextMarkers";
 NSString* const NSAccessibilityIndexForChildUIElementParameterizedAttribute =
     @"AXIndexForChildUIElement";
 
 // Actions.
 NSString* const NSAccessibilityScrollToVisibleAction = @"AXScrollToVisible";
 
 // A mapping from an accessibility attribute to its method name.
 NSDictionary* attributeToMethodNameMap = nil;
 
-struct AXTextMarkerData {
-  AXTreeIDRegistry::AXTreeID tree_id;
-  int32_t node_id;
-  int offset;
-  ui::AXTextAffinity affinity;
-};
-
 // VoiceOver uses -1 to mean "no limit" for AXResultsLimit.
 const int kAXResultsLimitNoLimit = -1;
 
 extern "C" {
 
 // The following are private accessibility APIs required for cursor navigation
 // and text selection. VoiceOver started relying on them in Mac OS X 10.11.
 #if !defined(MAC_OS_X_VERSION_10_11) || \
     MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_11
 
@@ skipping 13 matching lines @@
 AXTextMarkerRef AXTextMarkerRangeCopyEndMarker(
     AXTextMarkerRangeRef text_marker_range);
 
 #endif  // MAC_OS_X_VERSION_10_11
 
 }  // extern "C"
 
 id CreateTextMarker(const BrowserAccessibility& object,
                     int offset,
                     ui::AXTextAffinity affinity) {
-  AXTextMarkerData marker_data;
-  marker_data.tree_id = object.manager() ? object.manager()->ax_tree_id() : -1;
-  marker_data.node_id = object.GetId();
-  marker_data.offset = offset;
-  marker_data.affinity = affinity;
+  if (!object.instance_active())
+    return nil;
+
+  const auto manager = object.manager();
+  DCHECK(manager);
+  auto marker_data = AXPlatformPosition::CreateTextPosition(
+      manager->ax_tree_id(), object.node_id(), offset, affinity);
   return (id)base::mac::CFTypeRefToNSObjectAutorelease(AXTextMarkerCreate(
-      kCFAllocatorDefault, reinterpret_cast<const UInt8*>(&marker_data),
-      sizeof(marker_data)));
+      kCFAllocatorDefault, reinterpret_cast<const UInt8*>(marker_data),
+      sizeof(*marker_data)));
 }
 
 id CreateTextMarkerRange(const BrowserAccessibility& start_object,
                          int start_offset,
                          ui::AXTextAffinity start_affinity,
                          const BrowserAccessibility& end_object,
                          int end_offset,
                          ui::AXTextAffinity end_affinity) {
   id start_marker = CreateTextMarker(
         start_object, start_offset, start_affinity);
   id end_marker = CreateTextMarker(end_object, end_offset, end_affinity);
   return (id)base::mac::CFTypeRefToNSObjectAutorelease(
       AXTextMarkerRangeCreate(kCFAllocatorDefault, start_marker, end_marker));
 }
 
 bool GetTextMarkerData(AXTextMarkerRef text_marker,
                        BrowserAccessibility** object,
                        int* offset,
                        ui::AXTextAffinity* affinity) {
   DCHECK(text_marker);
   DCHECK(object && offset);
-  const auto* marker_data = reinterpret_cast<const AXTextMarkerData*>(
+  const auto* marker_data = reinterpret_cast<const AXPlatformPosition*>(
       AXTextMarkerGetBytePtr(text_marker));
   if (!marker_data)
     return false;
 
-  const BrowserAccessibilityManager* manager =
-      BrowserAccessibilityManager::FromID(marker_data->tree_id);
-  if (!manager)
-    return false;
-
-  *object = manager->GetFromID(marker_data->node_id);
+  *object = marker_data->GetAnchor();
   if (!*object)
     return false;
 
-  *offset = marker_data->offset;
+  *offset = marker_data->text_offset();
   if (*offset < 0)
     return false;
 
-  *affinity = marker_data->affinity;
-
+  *affinity = marker_data->affinity();
   return true;
 }
 
 bool GetTextMarkerRange(AXTextMarkerRangeRef marker_range,
                         BrowserAccessibility** start_object,
                         int* start_offset,
                         ui::AXTextAffinity* start_affinity,
                         BrowserAccessibility** end_object,
                         int* end_offset,
                         ui::AXTextAffinity* end_affinity) {
@@ skipping 2682 matching lines @@
 }
 
 - (BOOL)accessibilityNotifiesWhenDestroyed {
   // Indicate that BrowserAccessibilityCocoa will post a notification when it's
   // destroyed (see -detach). This allows VoiceOver to do some internal things
   // more efficiently.
   return YES;
 }
 
 @end