Improve support for multiselect list box accessibility on Windows.

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
===================================================================
--- content/browser/accessibility/browser_accessibility_win.cc	(revision 111700)
+++ content/browser/accessibility/browser_accessibility_win.cc	(working copy)
@@ -7,6 +7,7 @@
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "base/win/enum_variant.h"
 #include "base/win/scoped_comptr.h"
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
 #include "content/common/view_messages.h"
@@ -168,7 +169,8 @@
       ia_state_(0),
       ia2_role_(0),
       ia2_state_(0),
-      first_time_(true) {
+      first_time_(true),
+      old_ia_state_(0) {
 }
 
 BrowserAccessibilityWin::~BrowserAccessibilityWin() {
@@ -529,7 +531,47 @@
   if (!instance_active_)
     return E_FAIL;
 
-  return E_NOTIMPL;
+  if (role_ != WebAccessibility::ROLE_LISTBOX)
+    return E_NOTIMPL;
+
+  unsigned long selected_count = 0;
+  for (size_t i = 0; i < children_.size(); i++) {

[David Tseng, 2011/11/30 19:07:09]

nit: ++i and elsewhere below.

[dmazzoni, 2011/11/30 19:55:39]

Done.

+    if (children_[i]->HasState(WebAccessibility::STATE_SELECTED))
+      selected_count++;
+  }
+
+  if (selected_count == 0) {
+    selected->vt = VT_EMPTY;
+    return S_OK;
+  }
+
+  if (selected_count == 1) {
+    for (size_t i = 0; i < children_.size(); i++) {
+      if (children_[i]->HasState(WebAccessibility::STATE_SELECTED)) {
+        selected->vt = VT_DISPATCH;
+        selected->pdispVal =
+            children_[i]->toBrowserAccessibilityWin()->NewReference();
+        return S_OK;
+      }
+    }
+  }
+
+  // Multiple items are selected.
+  base::win::EnumVariant* enum_variant =
+      new base::win::EnumVariant(selected_count);
+  enum_variant->AddRef();
+  unsigned long index = 0;
+  for (size_t i = 0; i < children_.size(); i++) {
+    if (children_[i]->HasState(WebAccessibility::STATE_SELECTED)) {
+      enum_variant->ItemAt(index)->vt = VT_DISPATCH;
+      enum_variant->ItemAt(index)->pdispVal =
+        children_[i]->toBrowserAccessibilityWin()->NewReference();
+      index++;
+    }
+  }
+  selected->vt = VT_UNKNOWN;
+  selected->punkVal = static_cast<base::win::IUnknownImpl*>(enum_variant);
+  return S_OK;

[David Tseng, 2011/11/30 19:07:09]

Could we integrate these three loops? Perhaps check for the "multiple" attribute
on the select node?

[dmazzoni, 2011/11/30 19:55:39]

The multiple attribute indicates whether selecting multiple items is possible,
not whether it's currently true.

I think two passes are necessary: one to determine how many items are selected,
which determines what output format is used, and then one loop to generate the
output. Trying to do that in one pass would mean constructing some extra objects
that get thrown away if not used.

 }
 
 STDMETHODIMP BrowserAccessibilityWin::accSelect(
@@ -683,6 +725,22 @@
   return S_OK;
 }
 
+STDMETHODIMP BrowserAccessibilityWin::get_groupPosition(
+    LONG* group_level,
+    LONG* similar_items_in_group,
+    LONG* position_in_group) {
+  if (role_ == WebAccessibility::ROLE_LISTBOX_OPTION &&
+      parent_ &&
+      parent_->role() == WebAccessibility::ROLE_LISTBOX) {
+    *group_level = 0;

[David Tseng, 2011/11/30 19:07:09]

Do we need to check for the validity of these pointers?

[dmazzoni, 2011/11/30 19:55:39]

Good catch, done.

+    *similar_items_in_group = parent_->child_count();
+    *position_in_group = index_in_parent_ + 1;
+    return S_OK;
+  }
+
+  return E_NOTIMPL;
+}
+
 //
 // IAccessibleImage methods.
 //
@@ -2335,6 +2393,16 @@
   // Expose "level" attribute for tree nodes.
   IntAttributeToIA2(WebAccessibility::ATTR_HIERARCHICAL_LEVEL, "level");
 
+  // Expose the set size and position in set for listbox options.
+  if (role_ == WebAccessibility::ROLE_LISTBOX_OPTION &&
+      parent_ &&
+      parent_->role() == WebAccessibility::ROLE_LISTBOX) {
+    ia2_attributes_.push_back(
+        L"setsize:" + base::IntToString16(parent_->child_count()));
+    ia2_attributes_.push_back(
+        L"setsize:" + base::IntToString16(index_in_parent_ + 1));
+  }
+
   // Expose live region attributes.
   StringAttributeToIA2(WebAccessibility::ATTR_LIVE_STATUS, "live");
   StringAttributeToIA2(WebAccessibility::ATTR_LIVE_RELEVANT, "relevant");
@@ -2387,9 +2455,11 @@
     }
   }
 
-  // If this is static text, put the text in the name rather than the value.
-  if (role_ == WebAccessibility::ROLE_STATIC_TEXT && name_.empty())
+  if (name_.empty() &&
+      (role_ == WebAccessibility::ROLE_LISTBOX_OPTION ||
+       role_ == WebAccessibility::ROLE_STATIC_TEXT)) {
     name_.swap(value_);
+  }
 
   // If this object doesn't have a name but it does have a description,
   // use the description as its name - because some screen readers only
@@ -2443,6 +2513,40 @@
     previous_text_ = text;
   }
 
+  // Fire events if the state has changed.
+  if (!first_time_ && ia_state_ != old_ia_state_) {
+    // Normally focus events are handled elsewhere, however
+    // focus for managed descendants is platform-specific.
+    // Fire a focus event if the focused descendant in a multi-select
+    // list box changes.
+    if (role_ == WebAccessibility::ROLE_LISTBOX_OPTION &&
+        (ia_state_ & STATE_SYSTEM_FOCUSABLE) &&
+        (ia_state_ & STATE_SYSTEM_SELECTABLE) &&
+        (ia_state_ & STATE_SYSTEM_FOCUSED) &&
+        !(old_ia_state_ & STATE_SYSTEM_FOCUSED)) {
+      ::NotifyWinEvent(EVENT_OBJECT_FOCUS,
+                       manager_->GetParentView(),
+                       OBJID_CLIENT,
+                       child_id());
+    }
+
+    if ((ia_state_ & STATE_SYSTEM_SELECTED) &&
+        !(old_ia_state_ & STATE_SYSTEM_SELECTED)) {
+      ::NotifyWinEvent(EVENT_OBJECT_SELECTIONADD,
+                       manager_->GetParentView(),
+                       OBJID_CLIENT,
+                       child_id());
+    } else if (!(ia_state_ & STATE_SYSTEM_SELECTED) &&
+               (old_ia_state_ & STATE_SYSTEM_SELECTED)) {
+      ::NotifyWinEvent(EVENT_OBJECT_SELECTIONREMOVE,
+                       manager_->GetParentView(),
+                       OBJID_CLIENT,
+                       child_id());
+    }
+
+    old_ia_state_ = ia_state_;
+  }
+
   first_time_ = false;
 }
 
@@ -2571,51 +2675,53 @@
   ia2_state_ = IA2_STATE_OPAQUE;
   ia2_attributes_.clear();
 
-  if ((state_ >> WebAccessibility::STATE_BUSY) & 1)
+  if (HasState(WebAccessibility::STATE_BUSY))
     ia_state_|= STATE_SYSTEM_BUSY;
-  if ((state_ >> WebAccessibility::STATE_CHECKED) & 1)
+  if (HasState(WebAccessibility::STATE_CHECKED))
     ia_state_ |= STATE_SYSTEM_CHECKED;
-  if ((state_ >> WebAccessibility::STATE_COLLAPSED) & 1)
+  if (HasState(WebAccessibility::STATE_COLLAPSED))
     ia_state_|= STATE_SYSTEM_COLLAPSED;
-  if ((state_ >> WebAccessibility::STATE_EXPANDED) & 1)
+  if (HasState(WebAccessibility::STATE_EXPANDED))
     ia_state_|= STATE_SYSTEM_EXPANDED;
-  if ((state_ >> WebAccessibility::STATE_FOCUSABLE) & 1)
+  if (HasState(WebAccessibility::STATE_FOCUSABLE))
     ia_state_|= STATE_SYSTEM_FOCUSABLE;
-  if ((state_ >> WebAccessibility::STATE_HASPOPUP) & 1)
+  if (HasState(WebAccessibility::STATE_HASPOPUP))
     ia_state_|= STATE_SYSTEM_HASPOPUP;
-  if ((state_ >> WebAccessibility::STATE_HOTTRACKED) & 1)
+  if (HasState(WebAccessibility::STATE_HOTTRACKED))
     ia_state_|= STATE_SYSTEM_HOTTRACKED;
-  if ((state_ >> WebAccessibility::STATE_INDETERMINATE) & 1)
+  if (HasState(WebAccessibility::STATE_INDETERMINATE))
     ia_state_|= STATE_SYSTEM_INDETERMINATE;
-  if ((state_ >> WebAccessibility::STATE_INVISIBLE) & 1)
+  if (HasState(WebAccessibility::STATE_INVISIBLE))
     ia_state_|= STATE_SYSTEM_INVISIBLE;
-  if ((state_ >> WebAccessibility::STATE_LINKED) & 1)
+  if (HasState(WebAccessibility::STATE_LINKED))
     ia_state_|= STATE_SYSTEM_LINKED;
-  if ((state_ >> WebAccessibility::STATE_MULTISELECTABLE) & 1)
+  if (HasState(WebAccessibility::STATE_MULTISELECTABLE)) {
+    ia_state_|= STATE_SYSTEM_EXTSELECTABLE;
     ia_state_|= STATE_SYSTEM_MULTISELECTABLE;
+  }
   // TODO(ctguil): Support STATE_SYSTEM_EXTSELECTABLE/accSelect.
-  if ((state_ >> WebAccessibility::STATE_OFFSCREEN) & 1)
+  if (HasState(WebAccessibility::STATE_OFFSCREEN))
     ia_state_|= STATE_SYSTEM_OFFSCREEN;
-  if ((state_ >> WebAccessibility::STATE_PRESSED) & 1)
+  if (HasState(WebAccessibility::STATE_PRESSED))
     ia_state_|= STATE_SYSTEM_PRESSED;
-  if ((state_ >> WebAccessibility::STATE_PROTECTED) & 1)
+  if (HasState(WebAccessibility::STATE_PROTECTED))
     ia_state_|= STATE_SYSTEM_PROTECTED;
-  if ((state_ >> WebAccessibility::STATE_REQUIRED) & 1)
+  if (HasState(WebAccessibility::STATE_REQUIRED))
     ia2_state_|= IA2_STATE_REQUIRED;
-  if ((state_ >> WebAccessibility::STATE_SELECTABLE) & 1)
+  if (HasState(WebAccessibility::STATE_SELECTABLE))
     ia_state_|= STATE_SYSTEM_SELECTABLE;
-  if ((state_ >> WebAccessibility::STATE_SELECTED) & 1)
+  if (HasState(WebAccessibility::STATE_SELECTED))
     ia_state_|= STATE_SYSTEM_SELECTED;
-  if ((state_ >> WebAccessibility::STATE_TRAVERSED) & 1)
+  if (HasState(WebAccessibility::STATE_TRAVERSED))
     ia_state_|= STATE_SYSTEM_TRAVERSED;
-  if ((state_ >> WebAccessibility::STATE_UNAVAILABLE) & 1)
+  if (HasState(WebAccessibility::STATE_UNAVAILABLE))
     ia_state_|= STATE_SYSTEM_UNAVAILABLE;
-  if ((state_ >> WebAccessibility::STATE_VERTICAL) & 1) {
+  if (HasState(WebAccessibility::STATE_VERTICAL)) {
     ia2_state_|= IA2_STATE_VERTICAL;
   } else {
     ia2_state_|= IA2_STATE_HORIZONTAL;
   }
-  if ((state_ >> WebAccessibility::STATE_VISITED) & 1)
+  if (HasState(WebAccessibility::STATE_VISITED))
     ia_state_|= STATE_SYSTEM_TRAVERSED;
 
   // The meaning of the readonly state on Windows is very different from
@@ -2788,6 +2894,11 @@
       break;
     case WebAccessibility::ROLE_LISTBOX_OPTION:
       ia_role_ = ROLE_SYSTEM_LISTITEM;
+      if (ia_state_ & STATE_SYSTEM_SELECTABLE) {
+        ia_state_ |= STATE_SYSTEM_FOCUSABLE;
+        if (HasState(WebAccessibility::STATE_FOCUSED))
+          ia_state_|= STATE_SYSTEM_FOCUSED;
+      }
       break;
     case WebAccessibility::ROLE_LIST_ITEM:
       ia_role_ = ROLE_SYSTEM_LISTITEM;