bug 77648 implementing get_AccSelection

r=aaronl sr=brendan

accessible/src/nsHTMLListboxAccessible.cpp

@@ -25,9 +25,13 @@
 #include "nsHTMLListboxAccessible.h"
 
 #include "nsCOMPtr.h"
+#include "nsIAccessibilityService.h"
+#include "nsIDOMHTMLCollection.h"
 #include "nsIDOMHTMLInputElement.h"
 #include "nsIDOMHTMLSelectElement.h"
+#include "nsIDOMHTMLOptionElement.h"
 #include "nsIFrame.h"
+#include "nsIServiceManager.h"
 #include "nsLayoutAtoms.h"
 
 /** ----- nsHTMLListboxAccessible ----- */
@@ -42,7 +46,7 @@ nsHTMLListboxAccessible::nsHTMLListboxAccessible(nsIDOMNode* aDOMNode,
 }
 
 /** Inherit the ISupports impl from nsAccessible */
-NS_IMPL_ISUPPORTS_INHERITED0(nsHTMLListboxAccessible, nsAccessible)
+NS_IMPL_ISUPPORTS_INHERITED1(nsHTMLListboxAccessible, nsAccessible, nsIAccessibleSelectable)
 
 /** 
   * Tell our caller we are a list ( there isn't a listbox value )
@@ -91,11 +95,58 @@ NS_IMETHODIMP nsHTMLListboxAccessible::GetAccChildCount(PRInt32 *_retval)
   *     of select options and then iterate through that pulling out the selected
   *     items and creating IAccessible objects for them. Put the IAccessibles in
   *     the nsISupportsArray and return them.
+  * retval will be nsnull if:
+  *    - there are no options in the select
+  *    - there are options but none are selected
+  *    - the DOMNode is not a nsIDOMHTMLSelectElement ( shouldn't happen )
   */
 NS_IMETHODIMP nsHTMLListboxAccessible::GetSelectedChildren(nsISupportsArray **_retval)
 {
+  nsCOMPtr<nsIDOMHTMLSelectElement> select(do_QueryInterface(mDOMNode));
+  if(select) {
+    nsCOMPtr<nsIDOMHTMLCollection> options;
+    // get all the options in the select
+    select->GetOptions(getter_AddRefs(options));
+    if (options) {
+      // set up variables we need to get the selected options and to get their nsIAccessile objects
+      PRUint32 length;
+      options->GetLength(&length);
+      nsCOMPtr<nsIAccessibilityService> accService(do_GetService("@mozilla.org/accessibilityService;1"));
+      nsCOMPtr<nsISupportsArray> selectedAccessibles;
+      NS_NewISupportsArray(getter_AddRefs(selectedAccessibles));
+      if (!selectedAccessibles || !accService)
+        return NS_ERROR_FAILURE;
+      // find the selected options and get the accessible objects;
+      PRBool isSelected = PR_FALSE;
+      nsCOMPtr<nsIPresContext> context;
+      GetPresContext(context);
+      for (PRUint32 i = 0 ; i < length ; i++) {
+        nsCOMPtr<nsIDOMNode> tempNode;
+        options->Item(i,getter_AddRefs(tempNode));
+        if (tempNode) {
+          nsCOMPtr<nsIDOMHTMLOptionElement> tempOption(do_QueryInterface(tempNode));
+          if (tempOption)
+            tempOption->GetSelected(&isSelected);
+          if (isSelected) {
+            nsCOMPtr<nsIAccessible> tempAccess;
+            accService->CreateHTMLSelectOptionAccessible(tempOption, this, context, getter_AddRefs(tempAccess));
+            if ( tempAccess )
+              selectedAccessibles->AppendElement(tempAccess);
+            isSelected = PR_FALSE;
+          }
+        }
+      }
+      selectedAccessibles->Count(&length); // reusing length
+      if ( length != 0 ) { // length of nsISupportsArray containing selected options
+        *_retval = selectedAccessibles;
+        NS_IF_ADDREF(*_retval);
+        return NS_OK;
+      }
+    }
+  }
+  // no options, not a select or none of the options are selected
   *_retval = nsnull;
-  return NS_ERROR_NOT_IMPLEMENTED;
+  return NS_OK;
 }
 
 /**

widget/src/windows/Accessible.cpp

@@ -37,6 +37,13 @@
 #include "nsINameSpaceManager.h"
 #include "String.h"
 
+// for the COM IEnumVARIANT solution in get_AccSelection()
+#define _ATLBASE_IMPL
+#include <atlbase.h>
+extern CComModule _Module;
+#define _ATLCOM_IMPL
+#include <atlcom.h>
+
  /* For documentation of the accessibility architecture, 
  * see http://lxr.mozilla.org/seamonkey/source/accessible/accessible-docs.html
  */
@@ -55,6 +62,7 @@ EXTERN_C GUID CDECL CLSID_Accessible =
  * Class Accessible
  */
 
+CComModule _Module;
 
 //-----------------------------------------------------
 // construction 
@@ -417,11 +425,83 @@ STDMETHODIMP Accessible::get_accFocus(
   pvarChild->vt = VT_EMPTY;
   return S_FALSE;
 }
-
+/**
+  * This method is called when a client wants to know which children of a node
+  *  are selected. Currently we only handle this for HTML selects, which are the
+  *  only nsIAccessible objects to implement nsIAccessibleSelectable.
+  *
+  * The VARIANT return value arguement is expected to either contain a single IAccessible
+  *  or an IEnumVARIANT of IAccessibles. We return the IEnumVARIANT regardless of the number
+  *  of options selected, unless there are none selected in which case we return an empty
+  *  VARIANT.
+  *
+  * The typedefs at the beginning set up the structure that will contain an array 
+  *  of the IAccessibles. It implements the IEnumVARIANT interface, allowing us to 
+  *  use it to return the IAccessibles in the VARIANT.
+  *
+  * We get the selected options from the select's accessible object and then put create 
+  *  IAccessible objects for them and put those in the CComObject<EnumeratorType> 
+  *  object. Then we put the CComObject<EnumeratorType> object in the VARIANT and return.
+  *
+  * returns a VT_EMPTY VARIANT if:
+  *  - there are no options in the select
+  *  - none of the options are selected
+  *  - there is an error QIing to IEnumVARIANT
+  *  - The object is not the type that can have children selected
+  */
 STDMETHODIMP Accessible::get_accSelection( 
       /* [retval][out] */ VARIANT __RPC_FAR *pvarChildren)
 {
+  typedef VARIANT                      ItemType;              /* type of the object to be stored in container */
+  typedef ItemType                     EnumeratorExposedType; /* the type of the item exposed by the enumerator interface */
+  typedef IEnumVARIANT                 EnumeratorInterface;   /* a COM enumerator ( IEnumXXXXX ) interface */
+  typedef _Copy<EnumeratorExposedType> EnumeratorCopyPolicy;  /* Copy policy class */
+  typedef CComEnum<EnumeratorInterface,
+                   &__uuidof(EnumeratorInterface),
+                   EnumeratorExposedType,
+                   EnumeratorCopyPolicy > EnumeratorType;
+
+  IEnumVARIANT* pUnk = NULL;
+  CComObject<EnumeratorType>* pEnum = NULL;
+  VariantInit(pvarChildren);
   pvarChildren->vt = VT_EMPTY;
+  
+  nsCOMPtr<nsIAccessibleSelectable> select(do_QueryInterface(mAccessible));
+  if (select) {  // do we have an nsIAccessibleSelectable?
+    // we have an accessible that can have children selected
+    nsCOMPtr<nsISupportsArray> selectedOptions;
+    // gets the selected options as nsIAccessibles.
+    select->GetSelectedChildren(getter_AddRefs(selectedOptions));
+    if (selectedOptions) { // false if the select has no children or none are selected
+      PRUint32 length;
+      selectedOptions->Count(&length);
+      CComVariant* optionArray = new CComVariant[length]; // needs to be a CComVariant to go into the EnumeratorType object
+
+      // 1) Populate an array to store in the enumeration
+      for (PRUint32 i = 0 ; i < length ; i++) {
+        nsCOMPtr<nsISupports> tempOption;
+        selectedOptions->GetElementAt(i,getter_AddRefs(tempOption)); // this expects an nsISupports
+        if (tempOption) {
+          nsCOMPtr<nsIAccessible> tempAccess(do_QueryInterface(tempOption));
+          if ( tempAccess ) {
+            optionArray[i] = NewAccessible(tempAccess, nsnull, mWnd);
+          }
+        }
+      }
+
+      // 2) Create and initialize the enumeration
+      HRESULT hr = CComObject<EnumeratorType>::CreateInstance(&pEnum);
+      pEnum->Init(&optionArray[0], &optionArray[length], NULL, AtlFlagCopy);
+      pEnum->QueryInterface(IID_IEnumVARIANT, reinterpret_cast<void**>(&pUnk));
+      delete [] optionArray; // clean up, the Init call copies the data (AtlFlagCopy)
+
+      // 3) Put the enumerator in the VARIANT
+      if (!pUnk)
+        return NS_ERROR_FAILURE;
+      pvarChildren->vt = VT_UNKNOWN;    // this must be VT_UNKNOWN for an IEnumVARIANT
+      pvarChildren->punkVal = pUnk;
+    }
+  }
   return S_OK;
 }