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// 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.
#ifndef CHROME_BROWSER_BROWSER_ACCESSIBILITY_H_
#define CHROME_BROWSER_BROWSER_ACCESSIBILITY_H_
#include <atlbase.h>
#include <atlcom.h>
#include <oleacc.h>
#include "webkit/glue/webaccessibility.h"
using webkit_glue::WebAccessibility;
////////////////////////////////////////////////////////////////////////////////
//
// BrowserAccessibility
//
// Class implementing the MSAA IAccessible COM interface for the
// Browser-Renderer communication of MSAA information, providing accessibility
// to be used by screen readers and other assistive technology (AT).
//
////////////////////////////////////////////////////////////////////////////////
class ATL_NO_VTABLE BrowserAccessibility
: public CComObjectRootEx<CComMultiThreadModel>,
public IDispatchImpl<IAccessible, &IID_IAccessible, &LIBID_Accessibility> {
public:
BEGIN_COM_MAP(BrowserAccessibility)
COM_INTERFACE_ENTRY2(IDispatch, IAccessible)
COM_INTERFACE_ENTRY(IAccessible)
END_COM_MAP()
BrowserAccessibility()
: iaccessible_id_(-1),
routing_id_(-1),
process_id_(-1),
parent_hwnd_(NULL),
instance_active_(false) {
}
~BrowserAccessibility() {}
HRESULT Initialize(int iaccessible_id,
int routing_id,
int process_id,
HWND parent_hwnd);
// Supported IAccessible methods.
// Performs the default action on a given object.
STDMETHODIMP accDoDefaultAction(VARIANT var_id);
// Retrieves the child element or child object at a given point on the screen.
STDMETHODIMP accHitTest(LONG x_left, LONG y_top, VARIANT* child);
// Retrieves the specified object's current screen location.
STDMETHODIMP accLocation(LONG* x_left,
LONG* y_top,
LONG* width,
LONG* height,
VARIANT var_id);
// Traverses to another UI element and retrieves the object.
STDMETHODIMP accNavigate(LONG nav_dir, VARIANT start, VARIANT* end);
// Retrieves an IDispatch interface pointer for the specified child.
STDMETHODIMP get_accChild(VARIANT var_child, IDispatch** disp_child);
// Retrieves the number of accessible children.
STDMETHODIMP get_accChildCount(LONG* child_count);
// Retrieves a string that describes the object's default action.
STDMETHODIMP get_accDefaultAction(VARIANT var_id, BSTR* default_action);
// Retrieves the object's description.
STDMETHODIMP get_accDescription(VARIANT var_id, BSTR* desc);
// Retrieves the object that has the keyboard focus.
STDMETHODIMP get_accFocus(VARIANT* focus_child);
// Retrieves the help information associated with the object.
STDMETHODIMP get_accHelp(VARIANT var_id, BSTR* help);
// Retrieves the specified object's shortcut.
STDMETHODIMP get_accKeyboardShortcut(VARIANT var_id, BSTR* access_key);
// Retrieves the name of the specified object.
STDMETHODIMP get_accName(VARIANT var_id, BSTR* name);
// Retrieves the IDispatch interface of the object's parent.
STDMETHODIMP get_accParent(IDispatch** disp_parent);
// Retrieves information describing the role of the specified object.
STDMETHODIMP get_accRole(VARIANT var_id, VARIANT* role);
// Retrieves the current state of the specified object.
STDMETHODIMP get_accState(VARIANT var_id, VARIANT* state);
// Returns the value associated with the object.
STDMETHODIMP get_accValue(VARIANT var_id, BSTR* value);
// Non-supported (by WebKit) IAccessible methods.
STDMETHODIMP accSelect(LONG flags_sel, VARIANT var_id) { return E_NOTIMPL; }
STDMETHODIMP get_accHelpTopic(BSTR* help_file,
VARIANT var_id,
LONG* topic_id);
STDMETHODIMP get_accSelection(VARIANT* selected);
// Deprecated functions, not implemented here.
STDMETHODIMP put_accName(VARIANT var_id, BSTR put_name) { return E_NOTIMPL; }
STDMETHODIMP put_accValue(VARIANT var_id, BSTR put_val) { return E_NOTIMPL; }
// Accessors/mutators.
HWND parent_hwnd() const { return parent_hwnd_;}
// Modify/retrieve the state (active/inactive) of this instance.
void set_instance_active(bool instance_active) {
instance_active_ = instance_active;
}
int instance_active() const { return instance_active_; }
int routing_id() const { return routing_id_; }
private:
// Creates an empty VARIANT. Used as the equivalent of a NULL (unused) input
// parameter.
VARIANT EmptyVariant() const {
VARIANT empty;
empty.vt = VT_EMPTY;
return empty;
}
// Wrapper functions, calling through to singleton instance of
// BrowserAccessibilityManager.
// Creates an instance of BrowserAccessibility, initializes it and sets the
// [iaccessible_id] and [parent_id].
STDMETHODIMP CreateInstance(REFIID iid,
int iaccessible_id,
void** interface_ptr);
// Composes and sends a message for requesting needed accessibility
// information. Unused LONG input parameters should be NULL, and the VARIANT
// an empty, valid instance.
bool RequestAccessibilityInfo(int iaccessible_func_id,
VARIANT var_id,
LONG input1, LONG input2);
// Accessors.
const WebAccessibility::OutParams& response();
// Returns a conversion from the BrowserAccessibilityRole (as defined in
// webkit/glue/webaccessibility.h) to an MSAA role.
long MSAARole(long browser_accessibility_role);
// Returns a conversion from the BrowserAccessibilityState (as defined in
// webkit/glue/webaccessibility.h) to MSAA states set.
long MSAAState(long browser_accessibility_state);
// Id to uniquely distinguish this instance in the render-side caching,
// mapping it to the correct IAccessible on that side. Initialized to -1.
int iaccessible_id_;
// The unique ids of this IAccessible instance. Used to help
// BrowserAccessibilityManager instance retrieve the correct member
// variables for this process.
int routing_id_;
int process_id_;
HWND parent_hwnd_;
// The instance should only be active if there is a non-terminated
// RenderProcessHost associated with it. The BrowserAccessibilityManager keeps
// track of this state, and sets it to false to disable all calls into the
// renderer from this instance of BroweserAccessibility, and have all
// IAccessible functions return E_FAIL.
bool instance_active_;
DISALLOW_COPY_AND_ASSIGN(BrowserAccessibility);
};
#endif // CHROME_BROWSER_BROWSER_ACCESSIBILITY_H_
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