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/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"
+#include "ui/accessibility/ax_position.h"
+#include "ui/accessibility/ax_range.h"
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 using content::AXTreeIDRegistry;
 using content::AccessibilityMatchPredicate;
 using content::BrowserAccessibility;
 using content::BrowserAccessibilityDelegate;
 using content::BrowserAccessibilityManager;
 using content::BrowserAccessibilityManagerMac;
 using content::ContentClient;
 using content::OneShotAccessibilityTreeSearch;
@@ skipping 52 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" {
 
 // See http://openradar.appspot.com/9896491. This SPI has been tested on 10.5,
 // 10.6, and 10.7. It allows accessibility clients to observe events posted on
 // this object.
 void NSAccessibilityUnregisterUniqueIdForUIElement(id element);
 
@@ skipping 18 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);
+  const AXPlatformPositionFactory factory;

[dmazzoni, 2016/10/05 18:15:30]

I'm assuming this needs to be updated?

I think creating an instance of AXPosition<BrowserAccessibility>
will probably result in a lot of compile errors that will
help clean up the design

+  AXPosition marker_data = factory.CreateTextPosition(manager->ax_tree_id(),
+                                                      object.node_id(), offset);
+  marker_data.set_affinity(affinity);
   return (id)base::mac::CFTypeRefToNSObjectAutorelease(AXTextMarkerCreate(
       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*>(
-      AXTextMarkerGetBytePtr(text_marker));
+  const auto* marker_data =
+      reinterpret_cast<const AXPosition*>(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->get_text_offset();
   if (*offset < 0)
     return false;
 
-  *affinity = marker_data->affinity;
-
+  *affinity = marker_data->get_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 2677 matching lines @@
   if (![self instanceActive])
     return [super hash];
   return browserAccessibility_->GetId();
 }
 
 - (BOOL)accessibilityShouldUseUniqueId {
   return YES;
 }
 
 @end