1 files changed, 581 insertions, 0 deletions
diff --git a/accessible/xpcom/xpcAccessibleMacInterface.mm b/accessible/xpcom/xpcAccessibleMacInterface.mm
new file mode 100644
index 0000000000..e05937360b
--- /dev/null
+++ b/accessible/xpcom/xpcAccessibleMacInterface.mm
@@ -0,0 +1,581 @@
+/* clang-format off */
+/* -*- Mode: Objective-C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* clang-format on */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpcAccessibleMacInterface.h"
+
+#include "nsCocoaUtils.h"
+#include "nsContentUtils.h"
+#include "nsIObserverService.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIXPConnect.h"
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/Services.h"
+#include "nsString.h"
+#include "js/PropertyAndElement.h"  // JS_Enumerate, JS_GetElement, JS_GetProperty, JS_GetPropertyById, JS_HasOwnProperty, JS_SetUCProperty
+
+#import "mozAccessible.h"
+
+using namespace mozilla::a11y;
+
+// xpcAccessibleMacNSObjectWrapper
+
+NS_IMPL_ISUPPORTS(xpcAccessibleMacNSObjectWrapper,
+                  nsIAccessibleMacNSObjectWrapper)
+
+xpcAccessibleMacNSObjectWrapper::xpcAccessibleMacNSObjectWrapper(id aNativeObj)
+    : mNativeObject(aNativeObj) {
+  [mNativeObject retain];
+}
+
+xpcAccessibleMacNSObjectWrapper::~xpcAccessibleMacNSObjectWrapper() {
+  [mNativeObject release];
+}
+
+id xpcAccessibleMacNSObjectWrapper::GetNativeObject() { return mNativeObject; }
+
+// xpcAccessibleMacInterface
+
+NS_IMPL_ISUPPORTS_INHERITED(xpcAccessibleMacInterface,
+                            xpcAccessibleMacNSObjectWrapper,
+                            nsIAccessibleMacInterface)
+
+xpcAccessibleMacInterface::xpcAccessibleMacInterface(Accessible* aObj)
+    : xpcAccessibleMacNSObjectWrapper(GetNativeFromGeckoAccessible(aObj)) {}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::GetAttributeNames(
+    nsTArray<nsString>& aAttributeNames) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  if (!mNativeObject || [mNativeObject isExpired]) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  for (NSString* name in [mNativeObject accessibilityAttributeNames]) {
+    nsAutoString attribName;
+    nsCocoaUtils::GetStringForNSString(name, attribName);
+    aAttributeNames.AppendElement(attribName);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::GetParameterizedAttributeNames(
+    nsTArray<nsString>& aAttributeNames) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  if (!mNativeObject || [mNativeObject isExpired]) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  for (NSString* name in
+       [mNativeObject accessibilityParameterizedAttributeNames]) {
+    nsAutoString attribName;
+    nsCocoaUtils::GetStringForNSString(name, attribName);
+    aAttributeNames.AppendElement(attribName);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::GetActionNames(nsTArray<nsString>& aActionNames) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  if (!mNativeObject || [mNativeObject isExpired]) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  for (NSString* name in [mNativeObject accessibilityActionNames]) {
+    nsAutoString actionName;
+    nsCocoaUtils::GetStringForNSString(name, actionName);
+    aActionNames.AppendElement(actionName);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::PerformAction(const nsAString& aActionName) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  if (!mNativeObject || [mNativeObject isExpired]) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  NSString* actionName = nsCocoaUtils::ToNSString(aActionName);
+  [mNativeObject accessibilityPerformAction:actionName];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::GetAttributeValue(const nsAString& aAttributeName,
+                                             JSContext* aCx,
+                                             JS::MutableHandleValue aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  if (!mNativeObject || [mNativeObject isExpired]) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  NSString* attribName = nsCocoaUtils::ToNSString(aAttributeName);
+  return NSObjectToJsValue(
+      [mNativeObject accessibilityAttributeValue:attribName], aCx, aResult);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::IsAttributeSettable(const nsAString& aAttributeName,
+                                               bool* aIsSettable) {
+  NS_ENSURE_ARG_POINTER(aIsSettable);
+
+  NSString* attribName = nsCocoaUtils::ToNSString(aAttributeName);
+  if ([mNativeObject
+          respondsToSelector:@selector(accessibilityIsAttributeSettable:)]) {
+    *aIsSettable = [mNativeObject accessibilityIsAttributeSettable:attribName];
+    return NS_OK;
+  }
+
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::SetAttributeValue(const nsAString& aAttributeName,
+                                             JS::HandleValue aAttributeValue,
+                                             JSContext* aCx) {
+  nsresult rv = NS_OK;
+  id obj = JsValueToNSObject(aAttributeValue, aCx, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  NSString* attribName = nsCocoaUtils::ToNSString(aAttributeName);
+  if ([mNativeObject respondsToSelector:@selector(accessibilitySetValue:
+                                                           forAttribute:)]) {
+    // The NSObject has an attribute setter, call that.
+    [mNativeObject accessibilitySetValue:obj forAttribute:attribName];
+    return NS_OK;
+  }
+
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacInterface::GetParameterizedAttributeValue(
+    const nsAString& aAttributeName, JS::HandleValue aParameter, JSContext* aCx,
+    JS::MutableHandleValue aResult) {
+  nsresult rv = NS_OK;
+  id paramObj = JsValueToNSObject(aParameter, aCx, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  NSString* attribName = nsCocoaUtils::ToNSString(aAttributeName);
+  return NSObjectToJsValue([mNativeObject accessibilityAttributeValue:attribName
+                                                         forParameter:paramObj],
+                           aCx, aResult);
+}
+
+bool xpcAccessibleMacInterface::SupportsSelector(SEL aSelector) {
+  // return true if we have this selector, and if isAccessibilitySelectorAllowed
+  // is implemented too whether it is "allowed".
+  return [mNativeObject respondsToSelector:aSelector] &&
+         (![mNativeObject respondsToSelector:@selector
+                          (isAccessibilitySelectorAllowed:selector:)] ||
+          [mNativeObject isAccessibilitySelectorAllowed:aSelector]);
+}
+
+nsresult xpcAccessibleMacInterface::NSObjectToJsValue(
+    id aObj, JSContext* aCx, JS::MutableHandleValue aResult) {
+  if (!aObj) {
+    aResult.set(JS::NullValue());
+  } else if ([aObj isKindOfClass:[NSString class]]) {
+    nsAutoString strVal;
+    nsCocoaUtils::GetStringForNSString((NSString*)aObj, strVal);
+    if (!mozilla::dom::ToJSValue(aCx, strVal, aResult)) {
+      return NS_ERROR_FAILURE;
+    }
+  } else if ([aObj isKindOfClass:[NSNumber class]]) {
+    // If the type being held by the NSNumber is a BOOL set js value
+    // to boolean. Otherwise use a double value.
+    if (strcmp([(NSNumber*)aObj objCType], @encode(BOOL)) == 0) {
+      if (!mozilla::dom::ToJSValue(aCx, [(NSNumber*)aObj boolValue], aResult)) {
+        return NS_ERROR_FAILURE;
+      }
+    } else {
+      if (!mozilla::dom::ToJSValue(aCx, [(NSNumber*)aObj doubleValue],
+                                   aResult)) {
+        return NS_ERROR_FAILURE;
+      }
+    }
+  } else if ([aObj isKindOfClass:[NSValue class]] &&
+             strcmp([(NSValue*)aObj objCType], @encode(NSPoint)) == 0) {
+    NSPoint point = [(NSValue*)aObj pointValue];
+    return NSObjectToJsValue(
+        @[
+          [NSNumber numberWithDouble:point.x],
+          [NSNumber numberWithDouble:point.y]
+        ],
+        aCx, aResult);
+  } else if ([aObj isKindOfClass:[NSValue class]] &&
+             strcmp([(NSValue*)aObj objCType], @encode(NSSize)) == 0) {
+    NSSize size = [(NSValue*)aObj sizeValue];
+    return NSObjectToJsValue(
+        @[
+          [NSNumber numberWithDouble:size.width],
+          [NSNumber numberWithDouble:size.height]
+        ],
+        aCx, aResult);
+  } else if ([aObj isKindOfClass:[NSValue class]] &&
+             strcmp([(NSValue*)aObj objCType], @encode(NSRange)) == 0) {
+    NSRange range = [(NSValue*)aObj rangeValue];
+    return NSObjectToJsValue(@[ @(range.location), @(range.length) ], aCx,
+                             aResult);
+  } else if ([aObj isKindOfClass:[NSValue class]] &&
+             strcmp([(NSValue*)aObj objCType], @encode(NSRect)) == 0) {
+    NSRect rect = [(NSValue*)aObj rectValue];
+    return NSObjectToJsValue(@{
+      @"origin" : [NSValue valueWithPoint:rect.origin],
+      @"size" : [NSValue valueWithSize:rect.size]
+    },
+                             aCx, aResult);
+  } else if ([aObj isKindOfClass:[NSArray class]]) {
+    NSArray* objArr = (NSArray*)aObj;
+
+    JS::RootedVector<JS::Value> v(aCx);
+    if (!v.resize([objArr count])) {
+      return NS_ERROR_FAILURE;
+    }
+    for (size_t i = 0; i < [objArr count]; ++i) {
+      nsresult rv = NSObjectToJsValue(objArr[i], aCx, v[i]);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    JSObject* arrayObj = JS::NewArrayObject(aCx, v);
+    if (!arrayObj) {
+      return NS_ERROR_FAILURE;
+    }
+    aResult.setObject(*arrayObj);
+  } else if ([aObj isKindOfClass:[NSDictionary class]]) {
+    JS::RootedObject obj(aCx, JS_NewPlainObject(aCx));
+    for (NSString* key in aObj) {
+      nsAutoString strKey;
+      nsCocoaUtils::GetStringForNSString(key, strKey);
+      JS::RootedValue value(aCx);
+      nsresult rv = NSObjectToJsValue(aObj[key], aCx, &value);
+      NS_ENSURE_SUCCESS(rv, rv);
+      JS_SetUCProperty(aCx, obj, strKey.get(), strKey.Length(), value);
+    }
+    aResult.setObject(*obj);
+  } else if ([aObj isKindOfClass:[NSAttributedString class]]) {
+    NSAttributedString* attrStr = (NSAttributedString*)aObj;
+    __block NSMutableArray* attrRunArray = [[NSMutableArray alloc] init];
+
+    [attrStr
+        enumerateAttributesInRange:NSMakeRange(0, [attrStr length])
+                           options:
+                               NSAttributedStringEnumerationLongestEffectiveRangeNotRequired
+                        usingBlock:^(NSDictionary* attributes, NSRange range,
+                                     BOOL* stop) {
+                          NSString* str =
+                              [[attrStr string] substringWithRange:range];
+                          if (!str || !attributes) {
+                            return;
+                          }
+
+                          NSMutableDictionary* attrRun =
+                              [attributes mutableCopy];
+                          attrRun[@"string"] = str;
+
+                          [attrRunArray addObject:attrRun];
+                        }];
+
+    // The attributed string is represented in js as an array of objects.
+    // Each object represents a run of text where the "string" property is the
+    // string value and all the AX* properties are the attributes.
+    return NSObjectToJsValue(attrRunArray, aCx, aResult);
+  } else if (CFGetTypeID(aObj) == CGColorGetTypeID()) {
+    const CGFloat* components = CGColorGetComponents((CGColorRef)aObj);
+    NSString* hexString = [NSString
+        stringWithFormat:@"#%02x%02x%02x", (int)(components[0] * 0xff),
+                         (int)(components[1] * 0xff),
+                         (int)(components[2] * 0xff)];
+    return NSObjectToJsValue(hexString, aCx, aResult);
+  } else if ([aObj respondsToSelector:@selector(isAccessibilityElement)]) {
+    // We expect all of our accessibility objects to implement
+    // isAccessibilityElement at the very least. If it is implemented we will
+    // assume its an accessibility object.
+    nsCOMPtr<nsIAccessibleMacInterface> obj =
+        new xpcAccessibleMacInterface(aObj);
+    return nsContentUtils::WrapNative(
+        aCx, obj, &NS_GET_IID(nsIAccessibleMacInterface), aResult);
+  } else {
+    // If this is any other kind of NSObject, just wrap it and return it.
+    // It will be opaque and immutable on the JS side, but it can be
+    // brought back to us in an argument.
+    nsCOMPtr<nsIAccessibleMacNSObjectWrapper> obj =
+        new xpcAccessibleMacNSObjectWrapper(aObj);
+    return nsContentUtils::WrapNative(
+        aCx, obj, &NS_GET_IID(nsIAccessibleMacNSObjectWrapper), aResult);
+  }
+
+  return NS_OK;
+}
+
+id xpcAccessibleMacInterface::JsValueToNSObject(JS::HandleValue aValue,
+                                                JSContext* aCx,
+                                                nsresult* aResult) {
+  *aResult = NS_OK;
+  if (aValue.isInt32()) {
+    return [NSNumber numberWithInteger:aValue.toInt32()];
+  } else if (aValue.isBoolean()) {
+    return [NSNumber numberWithBool:aValue.toBoolean()];
+  } else if (aValue.isString()) {
+    nsAutoJSString temp;
+    if (!temp.init(aCx, aValue)) {
+      NS_WARNING("cannot init string with given value");
+      *aResult = NS_ERROR_FAILURE;
+      return nil;
+    }
+    return nsCocoaUtils::ToNSString(temp);
+  } else if (aValue.isObject()) {
+    JS::Rooted<JSObject*> obj(aCx, aValue.toObjectOrNull());
+
+    bool isArray;
+    JS::IsArrayObject(aCx, obj, &isArray);
+    if (isArray) {
+      // If this is an array, we construct an NSArray and insert the js
+      // array's elements by recursively calling this function.
+      uint32_t len;
+      JS::GetArrayLength(aCx, obj, &len);
+      NSMutableArray* array = [NSMutableArray arrayWithCapacity:len];
+      for (uint32_t i = 0; i < len; i++) {
+        JS::RootedValue v(aCx);
+        JS_GetElement(aCx, obj, i, &v);
+        [array addObject:JsValueToNSObject(v, aCx, aResult)];
+        NS_ENSURE_SUCCESS(*aResult, nil);
+      }
+      return array;
+    }
+
+    bool hasValueType;
+    bool hasValue;
+    JS_HasOwnProperty(aCx, obj, "valueType", &hasValueType);
+    JS_HasOwnProperty(aCx, obj, "value", &hasValue);
+    if (hasValueType && hasValue) {
+      // A js object representin an NSValue looks like this:
+      // { valueType: "NSRange", value: [1, 3] }
+      return JsValueToNSValue(obj, aCx, aResult);
+    }
+
+    bool hasObjectType;
+    bool hasObject;
+    JS_HasOwnProperty(aCx, obj, "objectType", &hasObjectType);
+    JS_HasOwnProperty(aCx, obj, "object", &hasObject);
+    if (hasObjectType && hasObject) {
+      // A js object representing an NSDictionary looks like this:
+      // { objectType: "NSDictionary", value: {k: v, k: v, ...} }
+      return JsValueToSpecifiedNSObject(obj, aCx, aResult);
+    }
+
+    // This may be another nsIAccessibleMacInterface instance.
+    // If so, return the wrapped NSObject.
+    nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+
+    nsCOMPtr<nsIXPConnectWrappedNative> wrappedObj;
+    nsresult rv =
+        xpc->GetWrappedNativeOfJSObject(aCx, obj, getter_AddRefs(wrappedObj));
+    NS_ENSURE_SUCCESS(rv, nil);
+    nsCOMPtr<nsIAccessibleMacNSObjectWrapper> macObjIface =
+        do_QueryInterface(wrappedObj->Native());
+    return macObjIface->GetNativeObject();
+  }
+
+  *aResult = NS_ERROR_FAILURE;
+  return nil;
+}
+
+id xpcAccessibleMacInterface::JsValueToNSValue(JS::HandleObject aObject,
+                                               JSContext* aCx,
+                                               nsresult* aResult) {
+  *aResult = NS_ERROR_FAILURE;
+  JS::RootedValue valueTypeValue(aCx);
+  if (!JS_GetProperty(aCx, aObject, "valueType", &valueTypeValue)) {
+    NS_WARNING("Could not get valueType");
+    return nil;
+  }
+
+  JS::RootedValue valueValue(aCx);
+  if (!JS_GetProperty(aCx, aObject, "value", &valueValue)) {
+    NS_WARNING("Could not get value");
+    return nil;
+  }
+
+  nsAutoJSString valueType;
+  if (!valueTypeValue.isString() || !valueType.init(aCx, valueTypeValue)) {
+    NS_WARNING("valueType is not a string");
+    return nil;
+  }
+
+  bool isArray;
+  JS::IsArrayObject(aCx, valueValue, &isArray);
+  if (!isArray) {
+    NS_WARNING("value is not an array");
+    return nil;
+  }
+
+  JS::Rooted<JSObject*> value(aCx, valueValue.toObjectOrNull());
+
+  if (valueType.EqualsLiteral("NSRange")) {
+    uint32_t len;
+    JS::GetArrayLength(aCx, value, &len);
+    if (len != 2) {
+      NS_WARNING("Expected a 2 member array");
+      return nil;
+    }
+
+    JS::RootedValue locationValue(aCx);
+    JS_GetElement(aCx, value, 0, &locationValue);
+    JS::RootedValue lengthValue(aCx);
+    JS_GetElement(aCx, value, 1, &lengthValue);
+    if (!locationValue.isInt32() || !lengthValue.isInt32()) {
+      NS_WARNING("Expected an array of integers");
+      return nil;
+    }
+
+    *aResult = NS_OK;
+    return [NSValue valueWithRange:NSMakeRange(locationValue.toInt32(),
+                                               lengthValue.toInt32())];
+  }
+
+  return nil;
+}
+
+id xpcAccessibleMacInterface::JsValueToSpecifiedNSObject(
+    JS::HandleObject aObject, JSContext* aCx, nsresult* aResult) {
+  *aResult = NS_ERROR_FAILURE;
+  JS::RootedValue objectTypeValue(aCx);
+  if (!JS_GetProperty(aCx, aObject, "objectType", &objectTypeValue)) {
+    NS_WARNING("Could not get objectType");
+    return nil;
+  }
+
+  JS::RootedValue objectValue(aCx);
+  if (!JS_GetProperty(aCx, aObject, "object", &objectValue)) {
+    NS_WARNING("Could not get object");
+    return nil;
+  }
+
+  nsAutoJSString objectType;
+  if (!objectTypeValue.isString()) {
+    NS_WARNING("objectType is not a string");
+    return nil;
+  }
+
+  if (!objectType.init(aCx, objectTypeValue)) {
+    NS_WARNING("cannot init string with object type");
+    return nil;
+  }
+
+  bool isObject = objectValue.isObjectOrNull();
+  if (!isObject) {
+    NS_WARNING("object is not a JSON object");
+    return nil;
+  }
+
+  JS::Rooted<JSObject*> object(aCx, objectValue.toObjectOrNull());
+
+  if (objectType.EqualsLiteral("NSDictionary")) {
+    JS::Rooted<JS::IdVector> ids(aCx, JS::IdVector(aCx));
+    if (!JS_Enumerate(aCx, object, &ids)) {
+      NS_WARNING("Unable to get keys from dictionary object");
+      return nil;
+    }
+
+    NSMutableDictionary* dict = [[NSMutableDictionary alloc] init];
+
+    for (size_t i = 0, n = ids.length(); i < n; i++) {
+      nsresult rv = NS_OK;
+      // get current key
+      JS::RootedValue currentKey(aCx);
+      JS_IdToValue(aCx, ids[i], &currentKey);
+      id unwrappedKey = JsValueToNSObject(currentKey, aCx, &rv);
+      NS_ENSURE_SUCCESS(rv, nil);
+      MOZ_ASSERT([unwrappedKey isKindOfClass:[NSString class]]);
+
+      // get associated value for current key
+      JS::RootedValue currentValue(aCx);
+      JS_GetPropertyById(aCx, object, ids[i], &currentValue);
+      id unwrappedValue = JsValueToNSObject(currentValue, aCx, &rv);
+      NS_ENSURE_SUCCESS(rv, nil);
+      dict[unwrappedKey] = unwrappedValue;
+    }
+
+    *aResult = NS_OK;
+    return dict;
+  }
+
+  return nil;
+}
+
+NS_IMPL_ISUPPORTS(xpcAccessibleMacEvent, nsIAccessibleMacEvent)
+
+xpcAccessibleMacEvent::xpcAccessibleMacEvent(id aNativeObj, id aData)
+    : mNativeObject(aNativeObj), mData(aData) {
+  [mNativeObject retain];
+  [mData retain];
+}
+
+xpcAccessibleMacEvent::~xpcAccessibleMacEvent() {
+  [mNativeObject release];
+  [mData release];
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacEvent::GetMacIface(nsIAccessibleMacInterface** aMacIface) {
+  RefPtr<xpcAccessibleMacInterface> macIface =
+      new xpcAccessibleMacInterface(mNativeObject);
+  macIface.forget(aMacIface);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+xpcAccessibleMacEvent::GetData(JSContext* aCx, JS::MutableHandleValue aData) {
+  return xpcAccessibleMacInterface::NSObjectToJsValue(mData, aCx, aData);
+}
+
+void xpcAccessibleMacEvent::FireEvent(id aNativeObj, id aNotification,
+                                      id aUserInfo) {
+  if (nsCOMPtr<nsIObserverService> obsService =
+          services::GetObserverService()) {
+    nsCOMPtr<nsISimpleEnumerator> observers;
+    // Get all observers for the mac event topic.
+    obsService->EnumerateObservers(NS_ACCESSIBLE_MAC_EVENT_TOPIC,
+                                   getter_AddRefs(observers));
+    if (observers) {
+      bool hasObservers = false;
+      observers->HasMoreElements(&hasObservers);
+      // If we have observers, notify them.
+      if (hasObservers) {
+        nsCOMPtr<nsIAccessibleMacEvent> xpcIface =
+            new xpcAccessibleMacEvent(aNativeObj, aUserInfo);
+        nsAutoString notificationStr;
+        nsCocoaUtils::GetStringForNSString(aNotification, notificationStr);
+        obsService->NotifyObservers(xpcIface, NS_ACCESSIBLE_MAC_EVENT_TOPIC,
+                                    notificationStr.get());
+      }
+    }
+  }
+}