Revert 46567 - Reimplement accessibility of web content by caching the entire...

chrome/browser/browser_accessibility_manager.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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 "base/scoped_comptr_win.h"
 #include "chrome/browser/browser_accessibility.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
+#include "chrome/common/notification_service.h"
 #include "chrome/common/render_messages.h"
 
 using webkit_glue::WebAccessibility;
 
-// Factory method to create an instance of BrowserAccessibility
-BrowserAccessibility* BrowserAccessibilityFactory::Create() {
-  CComObject<BrowserAccessibility>* instance;
-  HRESULT hr = CComObject<BrowserAccessibility>::CreateInstance(&instance);
-  DCHECK(SUCCEEDED(hr));
-  return instance->NewReference();
+// 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 = 10000;
+
+// static
+BrowserAccessibilityManager* BrowserAccessibilityManager::GetInstance() {
+  return Singleton<BrowserAccessibilityManager>::get();
 }
 
-// static
-// Start child IDs at -1 and decrement each time, because clients use
-// child IDs of 1, 2, 3, ... to access the children of an object by
-// index, so we use negative IDs to clearly distinguish between indices
-// and unique IDs.
-LONG BrowserAccessibilityManager::next_child_id_ = -1;
-
-BrowserAccessibilityManager::BrowserAccessibilityManager(
-    HWND parent_hwnd,
-    const webkit_glue::WebAccessibility& src,
-    BrowserAccessibilityFactory* factory)
-    : parent_hwnd_(parent_hwnd),
-      factory_(factory) {
-  HRESULT hr = ::CreateStdAccessibleObject(
-      parent_hwnd_, OBJID_WINDOW, IID_IAccessible,
-      reinterpret_cast<void **>(&window_iaccessible_));
-  DCHECK(SUCCEEDED(hr));
-  root_ = CreateAccessibilityTree(NULL, src, 0);
-  if (!focus_)
-    focus_ = root_;
+BrowserAccessibilityManager::BrowserAccessibilityManager() {
+  registrar_.Add(this, NotificationType::RENDERER_PROCESS_TERMINATED,
+                 NotificationService::AllSources());
 }
 
 BrowserAccessibilityManager::~BrowserAccessibilityManager() {
-  // Clients could still hold references to some nodes of the tree, so
-  // calling Inactivate will make sure that as many nodes as possible are
-  // released now, and remaining nodes are marked as inactive so that
-  // calls to any methods on them will return E_FAIL;
-  root_->InactivateTree();
-  root_->Release();
+  // Clear hashmap.
+  render_process_host_map_.clear();
 }
 
-BrowserAccessibility* BrowserAccessibilityManager::GetRoot() {
-  return root_;
+STDMETHODIMP BrowserAccessibilityManager::CreateAccessibilityInstance(
+    REFIID iid, int acc_obj_id, int routing_id, int process_id,
+    HWND parent_hwnd, 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;
+
+    ScopedComPtr<IAccessible> accessibility_instance(instance);
+
+    // Set class member variables.
+    instance->Initialize(acc_obj_id, routing_id, process_id, parent_hwnd);
+
+    // Retrieve the RenderViewHost connected to this request.
+    RenderViewHost* rvh = RenderViewHost::FromID(process_id, routing_id);
+
+    // Update cache with RenderProcessHost/BrowserAccessibility pair.
+    if (rvh && rvh->process()) {
+      render_process_host_map_.insert(MapEntry(rvh->process()->id(), 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;
 }
 
-BrowserAccessibility* BrowserAccessibilityManager::GetFromChildID(
-    LONG child_id) {
-  base::hash_map<LONG, BrowserAccessibility*>::iterator iter =
-      child_id_map_.find(child_id);
-  if (iter != child_id_map_.end()) {
-    return iter->second;
-  } else {
-    return NULL;
+bool BrowserAccessibilityManager::RequestAccessibilityInfo(
+    WebAccessibility::InParams* in, int routing_id, int process_id) {
+  // Create and populate IPC message structure, for retrieval of accessibility
+  // information from the renderer.
+  WebAccessibility::InParams in_params;
+  in_params.object_id = in->object_id;
+  in_params.function_id = in->function_id;
+  in_params.child_id = in->child_id;
+  in_params.input_long1 = in->input_long1;
+  in_params.input_long2 = in->input_long2;
+
+  // Retrieve the RenderViewHost connected to this request.
+  RenderViewHost* rvh = RenderViewHost::FromID(process_id, routing_id);
+
+  // Send accessibility information retrieval message to the renderer.
+  bool success = false;
+  if (rvh && rvh->process() && rvh->process()->HasConnection()) {
+    IPC::SyncMessage* msg =
+        new ViewMsg_GetAccessibilityInfo(routing_id, in_params, &out_params_);
+    // Necessary for the send to keep the UI responsive.
+    msg->EnableMessagePumping();
+    success = rvh->process()->SendWithTimeout(msg,
+        kAccessibilityMessageTimeOut);
   }
+  return success;
 }
 
-IAccessible* BrowserAccessibilityManager::GetParentWindowIAccessible() {
-  return window_iaccessible_;
+bool BrowserAccessibilityManager::ChangeAccessibilityFocus(int acc_obj_id,
+                                                           int process_id,
+                                                           int routing_id) {
+  BrowserAccessibility* browser_acc =
+      GetBrowserAccessibility(process_id, routing_id);
+  if (browser_acc) {
+    // Notify Access Technology that there was a change in keyboard focus.
+    ::NotifyWinEvent(EVENT_OBJECT_FOCUS, browser_acc->parent_hwnd(),
+                     OBJID_CLIENT, static_cast<LONG>(acc_obj_id));
+    return true;
+  }
+  return false;
 }
 
-HWND BrowserAccessibilityManager::GetParentHWND() {
-  return parent_hwnd_;
+bool BrowserAccessibilityManager::OnAccessibilityObjectStateChange(
+    int acc_obj_id, int process_id, int routing_id) {
+  BrowserAccessibility* browser_acc =
+      GetBrowserAccessibility(process_id, routing_id);
+  if (browser_acc) {
+    // Notify Access Technology that there was a change in state.
+    ::NotifyWinEvent(EVENT_OBJECT_STATECHANGE, browser_acc->parent_hwnd(),
+                     OBJID_CLIENT, static_cast<LONG>(acc_obj_id));
+    return true;
+  }
+  return false;
 }
 
-BrowserAccessibility* BrowserAccessibilityManager::GetFocus(
-    BrowserAccessibility* root) {
-  if (focus_ && (!root || focus_->IsDescendantOf(root)))
-    return focus_;
+const WebAccessibility::OutParams& BrowserAccessibilityManager::response() {
+  return out_params_;
+}
 
+BrowserAccessibility* BrowserAccessibilityManager::GetBrowserAccessibility(
+    int process_id, int routing_id) {
+  // Retrieve the BrowserAccessibility connected to the requester's id. There
+  // could be multiple BrowserAccessibility connected to the given |process_id|,
+  // but they all have the same parent HWND, so using the first hit is fine.
+  RenderProcessHostMap::iterator it =
+      render_process_host_map_.lower_bound(process_id);
+
+  RenderProcessHostMap::iterator end_of_matching_objects =
+    render_process_host_map_.upper_bound(process_id);
+
+  for (; it != end_of_matching_objects; ++it) {
+    if (it->second && it->second->routing_id() == routing_id)
+      return it->second;
+  }
   return NULL;
 }
 
-void BrowserAccessibilityManager::OnAccessibilityFocusChange(int renderer_id) {
-  base::hash_map<int, LONG>::iterator iter =
-      renderer_id_to_child_id_map_.find(renderer_id);
-  if (iter == renderer_id_to_child_id_map_.end())
-    return;
+void BrowserAccessibilityManager::Observe(NotificationType type,
+                                          const NotificationSource& source,
+                                          const NotificationDetails& details) {
+  DCHECK(type == NotificationType::RENDERER_PROCESS_TERMINATED);
+  RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
+  DCHECK(rph);
 
-  LONG child_id = iter->second;
-  base::hash_map<LONG, BrowserAccessibility*>::iterator uniq_iter =
-    child_id_map_.find(child_id);
-  if (uniq_iter != child_id_map_.end())
-    focus_ = uniq_iter->second;
-  ::NotifyWinEvent(EVENT_OBJECT_FOCUS, parent_hwnd_, OBJID_CLIENT, child_id);
+  RenderProcessHostMap::iterator it =
+      render_process_host_map_.lower_bound(rph->id());
+
+  RenderProcessHostMap::iterator end_of_matching_objects =
+    render_process_host_map_.upper_bound(rph->id());
+
+  for (; it != end_of_matching_objects; ++it) {
+    if (it->second) {
+      // Set all matching BrowserAccessibility instances to inactive state.
+      // TODO(klink): Do more active memory cleanup as well.
+      it->second->set_instance_active(false);
+    }
+  }
 }
-
-void BrowserAccessibilityManager::OnAccessibilityObjectStateChange(
-    int renderer_id) {
-  base::hash_map<int, LONG>::iterator iter =
-      renderer_id_to_child_id_map_.find(renderer_id);
-  if (iter == renderer_id_to_child_id_map_.end())
-    return;
-
-  LONG child_id = iter->second;
-  ::NotifyWinEvent(EVENT_OBJECT_FOCUS, parent_hwnd_, OBJID_CLIENT, child_id);
-}
-
-BrowserAccessibility* BrowserAccessibilityManager::CreateAccessibilityTree(
-    BrowserAccessibility* parent,
-    const webkit_glue::WebAccessibility& src,
-    int index_in_parent) {
-  BrowserAccessibility* instance = factory_->Create();
-
-  // Get the next child ID, and wrap around when we get near the end
-  // of a 32-bit integer range. It's okay to wrap around; we just want
-  // to avoid it as long as possible because clients may cache the ID of
-  // an object for a while to determine if they've seen it before.
-  LONG child_id = next_child_id_;
-  next_child_id_--;
-  if (next_child_id_ == -2000000000)
-    next_child_id_ = -1;
-
-  instance->Initialize(this, parent, child_id, index_in_parent, src);
-  child_id_map_[child_id] = instance;
-  renderer_id_to_child_id_map_[src.id] = child_id;
-  if ((src.state >> WebAccessibility::STATE_FOCUSED) & 1)
-    focus_ = instance;
-  for (int i = 0; i < static_cast<int>(src.children.size()); ++i) {
-    BrowserAccessibility* child = CreateAccessibilityTree(
-        instance, src.children[i], i);
-    instance->AddChild(child);
-  }
-
-  return instance;
-}