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// Copyright (c) 2012 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.
#ifndef CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
#define CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
#include <vector>
#include "base/containers/hash_tables.h"
#include "base/memory/weak_ptr.h"
#include "content/common/accessibility_node_data.h"
#include "content/public/renderer/render_view_observer.h"
#include "content/renderer/accessibility/renderer_accessibility.h"
#include "third_party/WebKit/public/web/WebAccessibilityNotification.h"
namespace WebKit {
class WebAccessibilityObject;
class WebDocument;
class WebNode;
};
namespace content {
class RenderViewImpl;
// This is the subclass of RendererAccessibility that implements
// complete accessibility support for assistive technology (as opposed to
// partial support - see RendererAccessibilityFocusOnly).
//
// This version turns on WebKit's accessibility code and sends
// a serialized representation of that tree whenever it changes. It also
// handles requests from the browser to perform accessibility actions on
// nodes in the tree (e.g., change focus, or click on a button).
class CONTENT_EXPORT RendererAccessibilityComplete
: public RendererAccessibility {
public:
explicit RendererAccessibilityComplete(RenderViewImpl* render_view);
virtual ~RendererAccessibilityComplete();
// RenderView::Observer implementation.
virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
virtual void FocusedNodeChanged(const WebKit::WebNode& node) OVERRIDE;
virtual void DidFinishLoad(WebKit::WebFrame* frame) OVERRIDE;
// RendererAccessibility.
virtual void HandleWebAccessibilityNotification(
const WebKit::WebAccessibilityObject& obj,
WebKit::WebAccessibilityNotification notification) OVERRIDE;
// In order to keep track of what nodes the browser knows about, we keep a
// representation of the browser tree - just IDs and parent/child
// relationships.
struct CONTENT_EXPORT BrowserTreeNode {
BrowserTreeNode();
virtual ~BrowserTreeNode();
int32 id;
gfx::Rect location;
BrowserTreeNode* parent;
std::vector<BrowserTreeNode*> children;
};
virtual BrowserTreeNode* CreateBrowserTreeNode();
protected:
// Send queued notifications from the renderer to the browser.
void SendPendingAccessibilityNotifications();
// Check the entire accessibility tree to see if any nodes have
// changed location, by comparing their locations to the cached
// versions. If any have moved, append a notification to |notifications|
// that updates the coordinates of these objects.
void AppendLocationChangeNotifications(
std::vector<AccessibilityHostMsg_NotificationParams>* notifications);
private:
// Handle an accessibility notification to be sent to the browser process.
void HandleAccessibilityNotification(
const WebKit::WebAccessibilityObject& obj,
AccessibilityNotification notification);
// Serialize the given accessibility object |obj| and append it to
// |dst|, and then recursively also serialize any *new* children of
// |obj|, based on what object ids we know the browser already has.
void SerializeChangedNodes(const WebKit::WebAccessibilityObject& obj,
std::vector<AccessibilityNodeData>* dst);
// Clear the given node and recursively delete all of its descendants
// from the browser tree. (Does not delete |browser_node|).
void ClearBrowserTreeNode(BrowserTreeNode* browser_node);
// Handlers for messages from the browser to the renderer.
void OnDoDefaultAction(int acc_obj_id);
void OnNotificationsAck();
void OnChangeScrollPosition(int acc_obj_id, int scroll_x, int scroll_y);
void OnScrollToMakeVisible(int acc_obj_id, gfx::Rect subfocus);
void OnScrollToPoint(int acc_obj_id, gfx::Point point);
void OnSetFocus(int acc_obj_id);
void OnSetTextSelection(int acc_obj_id, int start_offset, int end_offset);
void OnFatalError();
// Checks if a WebKit accessibility object is an editable text node.
bool IsEditableText(const WebKit::WebAccessibilityObject& node);
// Recursively explore the tree of WebKit accessibility objects rooted
// at |src|, and for each editable text node encountered, add a
// corresponding WebAccessibility node as a child of |dst|.
void RecursiveAddEditableTextNodesToTree(
const WebKit::WebAccessibilityObject& src,
AccessibilityNodeData* dst);
// Build a tree of serializable AccessibilityNodeData nodes to send to the
// browser process, given a WebAccessibilityObject node from WebKit.
// Modifies |dst| in-place, it's assumed to be empty.
void BuildAccessibilityTree(const WebKit::WebAccessibilityObject& src,
bool include_children,
AccessibilityNodeData* dst);
// So we can queue up tasks to be executed later.
base::WeakPtrFactory<RendererAccessibilityComplete> weak_factory_;
// Notifications from WebKit are collected until they are ready to be
// sent to the browser.
std::vector<AccessibilityHostMsg_NotificationParams> pending_notifications_;
// Our representation of the browser tree.
BrowserTreeNode* browser_root_;
// A map from IDs to nodes in the browser tree.
base::hash_map<int32, BrowserTreeNode*> browser_id_map_;
// The most recently observed scroll offset of the root document element.
// TODO(dmazzoni): remove once https://bugs.webkit.org/show_bug.cgi?id=73460
// is fixed.
gfx::Size last_scroll_offset_;
// The current accessibility mode.
AccessibilityMode mode_;
// Set if we are waiting for an accessibility notification ack.
bool ack_pending_;
// True if verbose logging of accessibility events is on.
bool logging_;
DISALLOW_COPY_AND_ASSIGN(RendererAccessibilityComplete);
};
#endif // CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
} // namespace content
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