Adds MSAA/IAccessible exposure of web content.

chrome/browser/browser_accessibility_manager.cc

+// Copyright (c) 2006-2008 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 "chrome/browser/browser_accessibility_manager.h"
+
+#include "chrome/browser/browser_accessibility.h"
+#include "chrome/browser/render_process_host.h"
+#include "chrome/browser/render_widget_host.h"
+
+// The time in ms after which we give up and return an error when processing an
+// accessibility message and no response has been received from the renderer.
+static const int kAccessibilityMessageTimeOut = 500;
+
+// static
+BrowserAccessibilityManager* BrowserAccessibilityManager::Instance() {
+  return Singleton<BrowserAccessibilityManager>::get();
+}
+
+BrowserAccessibilityManager::BrowserAccessibilityManager()
+    : instance_id_(0) {
+  NotificationService::current()->AddObserver(this,
+      NOTIFY_RENDERER_PROCESS_TERMINATED, NotificationService::AllSources());
+}
+
+BrowserAccessibilityManager::~BrowserAccessibilityManager() {
+  // Clear hashmaps.
+  instance_map_.clear();
+  render_process_host_map_.clear();
+
+  NotificationService::current()->RemoveObserver(this,
+      NOTIFY_RENDERER_PROCESS_TERMINATED, NotificationService::AllSources());
+}
+
+STDMETHODIMP BrowserAccessibilityManager::CreateAccessibilityInstance(
+    REFIID iid, int iaccessible_id, int instance_id, void** interface_ptr) {
+  if (IID_IUnknown == iid || IID_IDispatch == iid || IID_IAccessible == iid) {
+    CComObject<BrowserAccessibility>* instance = NULL;
+
+    HRESULT hr = CComObject<BrowserAccessibility>::CreateInstance(&instance);
+    DCHECK(SUCCEEDED(hr));
+
+    if (!instance)
+      return E_FAIL;
+
+    CComPtr<IAccessible> accessibility_instance(instance);
+
+    // Set unique ids.
+    instance->set_iaccessible_id(iaccessible_id);
+    instance->set_instance_id(instance_id);
+
+    // Retrieve the RenderWidgetHost connected to this request.
+    InstanceMap::iterator it = instance_map_.find(instance_id);
+
+    if (it != instance_map_.end()) {
+      UniqueMembers* members = it->second;
+
+      if (!members || !members->render_widget_host_)
+        return E_FAIL;
+
+      render_process_host_map_[members->render_widget_host_->process()] =
+          instance;
+    } else {
+      // No RenderProcess active for this instance.
+      return E_FAIL;
+    }
+
+    // All is well, assign the temp instance to the output pointer.
+    *interface_ptr = accessibility_instance.Detach();
+    return S_OK;
+  }
+  // No supported interface found, return error.
+  *interface_ptr = NULL;
+  return E_NOINTERFACE;
+}
+
+bool BrowserAccessibilityManager::RequestAccessibilityInfo(
+    int iaccessible_id, int instance_id, int iaccessible_func_id,
+    VARIANT var_id, LONG input1, LONG input2) {
+  // Create and populate input message structure.
+  ViewMsg_Accessibility_In_Params in_params;
+
+  in_params.iaccessible_id = iaccessible_id;
+  in_params.iaccessible_function_id = iaccessible_func_id;
+  in_params.input_variant_lval = var_id.lVal;
+  in_params.input_long1 = input1;
+  in_params.input_long2 = input2;
+
+  // Retrieve the RenderWidgetHost connected to this request.
+  InstanceMap::iterator it = instance_map_.find(instance_id);
+
+  if (it == instance_map_.end()) {
+    // Id not found.
+    return false;
+  }
+
+  UniqueMembers* members = it->second;
+
+  if (!members || !members->render_widget_host_)
+    return false;
+
+  IPC::SyncMessage* msg =
+      new ViewMsg_GetAccessibilityInfo(
+          members->render_widget_host_->routing_id(), in_params, &out_params_);
+
+  // Necessary for the send to keep the UI responsive.
+  msg->EnableMessagePumping();
+  bool success = members->render_widget_host_->process()->channel()->
+      SendWithTimeout(msg, kAccessibilityMessageTimeOut);
+
+  return success;
+}
+
+ViewHostMsg_Accessibility_Out_Params BrowserAccessibilityManager::response() {
+  return out_params_;
+}
+
+HWND BrowserAccessibilityManager::parent_hwnd(int id) {
+  // Retrieve the parent HWND connected to the requester's id.
+  InstanceMap::iterator it = instance_map_.find(id);
+
+  if (it == instance_map_.end()) {
+    // Id not found.
+    return NULL;
+  }
+
+  UniqueMembers* members = it->second;
+
+  if (!members || !members->parent_hwnd_)
+    return NULL;
+
+  return members->parent_hwnd_;
+}
+
+int BrowserAccessibilityManager::SetMembers(BrowserAccessibility* browser_acc,
+    HWND parent_hwnd, RenderWidgetHost* render_widget_host) {
+  // Set HWND and RenderWidgetHost connected to |browser_acc|.
+  instance_map_[instance_id_] =
+      new UniqueMembers(parent_hwnd, render_widget_host);
+
+  render_process_host_map_[render_widget_host->process()] = browser_acc;
+  return instance_id_++;
+}
+
+void BrowserAccessibilityManager::Observe(NotificationType type,
+                                          const NotificationSource& source,
+                                          const NotificationDetails& details) {
+  DCHECK(type == NOTIFY_RENDERER_PROCESS_TERMINATED);
+  RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
+  DCHECK(rph);
+  RenderProcessHostMap::iterator it = render_process_host_map_.find(rph);
+
+  if (it == render_process_host_map_.end() || !it->second) {
+    // RenderProcessHost not associated with any BrowserAccessibility instance.
+    return;
+  }
+
+  // Set BrowserAccessibility instance to inactive state.
+  it->second->set_instance_active(false);
+  render_process_host_map_.erase(it);
+
+  // Delete entry also from InstanceMap.
+  InstanceMap::iterator it2 = instance_map_.find(it->second->instance_id());
+
+  if (it2 != instance_map_.end())
+    instance_map_.erase(it2);
+}