Mac: Add new accessibility attributes for textfields (and some for all views).

ui/accessibility/platform/ax_platform_node_mac.mm

 // Copyright 2014 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.
 
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 
 namespace {
 
-struct MapEntry {
+struct RoleMapEntry {
   ui::AXRole value;
   NSString* nativeValue;
 };
 
+struct EventMapEntry {
+  ui::AXEvent value;
+  NSString* nativeValue;
+};
+
 typedef std::map<ui::AXRole, NSString*> RoleMap;
+typedef std::map<ui::AXEvent, NSString*> EventMap;
 
 RoleMap BuildRoleMap() {
-  const MapEntry roles[] = {
+  const RoleMapEntry roles[] = {
       {ui::AX_ROLE_ABBR, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ALERT, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ALERT_DIALOG, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ANNOTATION, NSAccessibilityUnknownRole},
       {ui::AX_ROLE_APPLICATION, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ARTICLE, NSAccessibilityGroupRole},
       {ui::AX_ROLE_BANNER, NSAccessibilityGroupRole},
       {ui::AX_ROLE_BLOCKQUOTE, NSAccessibilityGroupRole},
       {ui::AX_ROLE_BUSY_INDICATOR, NSAccessibilityBusyIndicatorRole},
       {ui::AX_ROLE_BUTTON, NSAccessibilityButtonRole},
@@ skipping 105 matching lines @@
       // { ui::AX_ROLE_SCROLL_AREA, NSAccessibilityScrollAreaRole },
   };
 
   RoleMap role_map;
   for (size_t i = 0; i < arraysize(roles); ++i)
     role_map[roles[i].value] = roles[i].nativeValue;
   return role_map;
 }
 
 RoleMap BuildSubroleMap() {
-  const MapEntry subroles[] = {
+  const RoleMapEntry subroles[] = {
       {ui::AX_ROLE_ALERT, @"AXApplicationAlert"},
       {ui::AX_ROLE_ALERT_DIALOG, @"AXApplicationAlertDialog"},
       {ui::AX_ROLE_APPLICATION, @"AXLandmarkApplication"},
       {ui::AX_ROLE_ARTICLE, @"AXDocumentArticle"},
       {ui::AX_ROLE_BANNER, @"AXLandmarkBanner"},
       {ui::AX_ROLE_COMPLEMENTARY, @"AXLandmarkComplementary"},
       {ui::AX_ROLE_CONTENT_INFO, @"AXLandmarkContentInfo"},
       {ui::AX_ROLE_DEFINITION, @"AXDefinition"},
       {ui::AX_ROLE_DESCRIPTION_LIST_DETAIL, @"AXDefinition"},
       {ui::AX_ROLE_DESCRIPTION_LIST_TERM, @"AXTerm"},
@@ skipping 18 matching lines @@
       {ui::AX_ROLE_TOOLTIP, @"AXUserInterfaceTooltip"},
       {ui::AX_ROLE_TREE_ITEM, NSAccessibilityOutlineRowSubrole},
   };
 
   RoleMap subrole_map;
   for (size_t i = 0; i < arraysize(subroles); ++i)
     subrole_map[subroles[i].value] = subroles[i].nativeValue;
   return subrole_map;
 }
 
+EventMap BuildEventMap() {
+  const EventMapEntry events[] = {
+      {ui::AX_EVENT_TEXT_CHANGED, NSAccessibilityTitleChangedNotification},
+      {ui::AX_EVENT_VALUE_CHANGED, NSAccessibilityValueChangedNotification},
+      {ui::AX_EVENT_TEXT_SELECTION_CHANGED,
+       NSAccessibilitySelectedTextChangedNotification},
+      // TODO(patricialor): Add more events.
+  };
+
+  EventMap event_map;
+  for (size_t i = 0; i < arraysize(events); ++i) {

[tapted, 2016/06/30 01:58:57]

nit: no curlies (consistent with the others)

[Patti Lor, 2016/06/30 05:29:54]

Done.

+    event_map[events[i].value] = events[i].nativeValue;
+  }
+  return event_map;
+}
+
+void NotifyMacEvent(ui::AXEvent event_type, gfx::AcceleratedWidget target) {

[tapted, 2016/06/30 01:58:57]

AcceleratedWidget -> NSView* (it's easier to read with the specific type, which
we can assume since this is mac-only)

[Patti Lor, 2016/06/30 05:29:54]

Done.

+  NSAccessibilityPostNotification(
+      target, [AXPlatformNodeCocoa nativeNotificationFromAXEvent:event_type]);
+}
+
 }  // namespace
 
 @interface AXPlatformNodeCocoa ()
 // Helper function for string attributes that don't require extra processing.
 - (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
 @end
 
 @implementation AXPlatformNodeCocoa
 
 // A mapping of AX roles to native roles.
 + (NSString*)nativeRoleFromAXRole:(ui::AXRole)role {
   CR_DEFINE_STATIC_LOCAL(RoleMap, role_map, (BuildRoleMap()));
   RoleMap::iterator it = role_map.find(role);
   return it != role_map.end() ? it->second : NSAccessibilityUnknownRole;
 }
 
 // A mapping of AX roles to native subroles.
 + (NSString*)nativeSubroleFromAXRole:(ui::AXRole)role {
   CR_DEFINE_STATIC_LOCAL(RoleMap, subrole_map, (BuildSubroleMap()));
   RoleMap::iterator it = subrole_map.find(role);
   return it != subrole_map.end() ? it->second : nil;
 }
 
+// A mapping of AX events to native notifications.
++ (NSString*)nativeNotificationFromAXEvent:(ui::AXEvent)event {
+  CR_DEFINE_STATIC_LOCAL(EventMap, event_map, (BuildEventMap()));
+  EventMap::iterator it = event_map.find(event);
+  return it != event_map.end() ? it->second : nil;
+}
+
 - (instancetype)initWithNode:(ui::AXPlatformNodeBase*)node {
   if ((self = [super init])) {
     node_ = node;
   }
   return self;
 }
 
 - (void)detach {
   node_ = nil;
 }
@@ skipping 38 matching lines @@
     NSAccessibilityRoleAttribute,
     NSAccessibilitySizeAttribute,
     NSAccessibilitySubroleAttribute,
 
     // Title is required for most elements. Cocoa asks for the value even if it
     // is omitted here, but won't present it to accessibility APIs without this.
     NSAccessibilityTitleAttribute,
 
     // Attributes which are not required, but are general to all roles.
     NSAccessibilityRoleDescriptionAttribute,
+    NSAccessibilityEnabledAttribute,
+    NSAccessibilityFocusedAttribute,
   ];
 
   // Attributes required for user-editable controls.
   NSArray* const kValueAttributes = @[ NSAccessibilityValueAttribute ];
 
+  // Attributes required for textfields.
+  NSArray* const kTextfieldAttributes = @[
+    NSAccessibilityInsertionPointLineNumberAttribute,
+    NSAccessibilityNumberOfCharactersAttribute,
+    NSAccessibilityPlaceholderValueAttribute,
+    NSAccessibilitySelectedTextAttribute,
+    NSAccessibilitySelectedTextRangeAttribute,
+    NSAccessibilityVisibleCharacterRangeAttribute,
+  ];
+
   base::scoped_nsobject<NSMutableArray> axAttributes(
       [[NSMutableArray alloc] init]);
 
   [axAttributes addObjectsFromArray:kAllRoleAttributes];
   switch (node_->GetData().role) {
+    case ui::AX_ROLE_TEXT_FIELD:
+      [axAttributes addObjectsFromArray:kTextfieldAttributes];
+    // Fallthrough.
     case ui::AX_ROLE_CHECK_BOX:
     case ui::AX_ROLE_COMBO_BOX:
     case ui::AX_ROLE_MENU_ITEM_CHECK_BOX:
     case ui::AX_ROLE_MENU_ITEM_RADIO:
     case ui::AX_ROLE_RADIO_BUTTON:
     case ui::AX_ROLE_SEARCH_BOX:
     case ui::AX_ROLE_SLIDER:
     case ui::AX_ROLE_SLIDER_THUMB:
     case ui::AX_ROLE_TOGGLE_BUTTON:
-    case ui::AX_ROLE_TEXT_FIELD:
       [axAttributes addObjectsFromArray:kValueAttributes];
       break;
     // TODO(tapted): Add additional attributes based on role.
     default:
       break;
   }
   return axAttributes.autorelease();
 }
 
 - (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute {
@@ skipping 61 matching lines @@
 }
 
 - (NSString*)AXTitle {
   return [self getStringAttribute:ui::AX_ATTR_NAME];
 }
 
 - (NSString*)AXValue {
   return [self getStringAttribute:ui::AX_ATTR_VALUE];
 }
 
+- (NSValue*)AXEnabled {
+  return [NSNumber
+      numberWithBool:!ui::AXViewState::IsFlagSet(node_->GetData().state,
+                                                 ui::AX_STATE_DISABLED)];
+}
+
+- (NSValue*)AXFocused {
+  if (ui::AXViewState::IsFlagSet(node_->GetData().state,
+                                 ui::AX_STATE_FOCUSABLE))
+    return [NSNumber numberWithBool:(node_->GetDelegate()->GetFocus() ==
+                                     node_->GetNativeViewAccessible())];
+  return [NSNumber numberWithBool:NO];
+}
+
+// Textfield-specific NSAccessibility attributes.
+
+- (NSNumber*)AXInsertionPointLineNumber {
+  // Multiline is not supported on views.
+  return [NSNumber numberWithInteger:0];
+}
+
+- (NSNumber*)AXNumberOfCharacters {
+  return [NSNumber numberWithInteger:[[self AXValue] length]];
+}
+
+- (NSString*)AXPlaceholderValue {
+  return [self getStringAttribute:ui::AX_ATTR_PLACEHOLDER];
+}
+
+- (NSString*)AXSelectedText {
+  NSRange selectedTextRange;
+  [[self AXSelectedTextRange] getValue:&selectedTextRange];
+  return [[self AXValue] substringWithRange:selectedTextRange];
+}
+
+- (NSValue*)AXSelectedTextRange {
+  int textDir, start, end;
+  node_->GetIntAttribute(ui::AX_ATTR_TEXT_DIRECTION, &textDir);
+  node_->GetIntAttribute(ui::AX_ATTR_TEXT_SEL_START, &start);
+  node_->GetIntAttribute(ui::AX_ATTR_TEXT_SEL_END, &end);
+  // NSRange cannot represent the direction the text was selected in, so make
+  // sure the correct selection index is used when creating a new range, taking
+  // into account the textfield text direction as well.
+  bool isReversed = (textDir == ui::AX_TEXT_DIRECTION_RTL) ||
+                    (textDir == ui::AX_TEXT_DIRECTION_BTT);
+  int beginSelectionIndex = (end > start && !isReversed) ? start : end;
+  return [NSValue
+      valueWithRange:NSMakeRange(beginSelectionIndex, abs(end - start))];
+}
+
+- (NSValue*)AXVisibleCharacterRange {
+  return [NSValue
+      valueWithRange:NSMakeRange(0, [[self AXNumberOfCharacters] intValue])];
+}
+
 @end
 
 namespace ui {
 
 // static
 AXPlatformNode* AXPlatformNode::Create(AXPlatformNodeDelegate* delegate) {
   AXPlatformNodeBase* node = new AXPlatformNodeMac();
   node->Init(delegate);
   return node;
 }
@@ skipping 10 matching lines @@
   AXPlatformNodeBase::Destroy();
 }
 
 gfx::NativeViewAccessible AXPlatformNodeMac::GetNativeViewAccessible() {
   if (!native_node_)
     native_node_.reset([[AXPlatformNodeCocoa alloc] initWithNode:this]);
   return native_node_.get();
 }
 
 void AXPlatformNodeMac::NotifyAccessibilityEvent(ui::AXEvent event_type) {
-  // TODO(dmazzoni): implement this.  http://crbug.com/396137
+  gfx::AcceleratedWidget target =

[tapted, 2016/06/30 01:58:57]

nit: NSView*

[Patti Lor, 2016/06/30 05:29:54]

Done.

+      GetDelegate()->GetTargetForNativeAccessibilityEvent();
+
+  // Add mappings between ui::AXEvent and NSAccessibility notifications using
+  // the EventMap above. This switch contains exceptions to those mappings.
+  switch (event_type) {
+    case ui::AX_EVENT_TEXT_CHANGED:
+      // If the view is a user-editable textfield, this should change the value.
+      if (GetData().role == ui::AX_ROLE_TEXT_FIELD) {
+        NSAccessibilityPostNotification(

[tapted, 2016/06/30 01:58:57]

I'd go with

NotifyMacEvent(target, ui::AX_EVENT_VALUE_CHANGED)

it's a bit clearer what the intention is then (also it's shorter :)

[Patti Lor, 2016/06/30 05:29:54]

Done, thanks!

+            target, NSAccessibilityValueChangedNotification);
+        return;
+      }
+      break;
+    default:
+      break;
+  }
+  NotifyMacEvent(event_type, target);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui