Implement AtkComponent interface for chrome UI.

ui/accessibility/platform/ax_platform_node_auralinux.cc

 // Copyright 2015 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 "ui/accessibility/platform/ax_platform_node_auralinux.h"
 
 #include "base/command_line.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/platform/atk_util_auralinux.h"
@@ skipping 219 matching lines @@
       (GBaseFinalizeFunc) 0,
       (GClassInitFunc) ax_platform_node_auralinux_class_init,
       (GClassFinalizeFunc) 0,
       0, /* class data */
       sizeof(AXPlatformNodeAuraLinuxObject), /* instance size */
       0, /* nb preallocs */
       (GInstanceInitFunc) 0,
       0 /* value table */
     };
 
     GType type = g_type_register_static(

[dmazzoni, 2015/03/30 16:21:22]

Immediately after this call, you should add a line of code like this:

g_type_add_interface_static(
          type,
          ATK_TYPE_COMPONENT,
          &ComponentInfo);

Then add something like this above it:

static const GInterfaceInfo ComponentInfo = {
  reinterpret_cast<GInterfaceInitFunc>(ax_component_interface_base_init), 0, 0
};

Obviously ax_component_interface_base_init needs to be moved above that.

Once you do that you shouldn't need ax_component_auralinux_get_type.

         ATK_TYPE_OBJECT, "AXPlatformNodeAuraLinux", &tinfo, GTypeFlags(0));
     g_once_init_leave(&type_volatile, type);
   }
 
   return type_volatile;
 }
 
 AXPlatformNodeAuraLinuxObject* ax_platform_node_auralinux_new(
     ui::AXPlatformNodeAuraLinux* obj) {
   #if !GLIB_CHECK_VERSION(2, 36, 0)
@@ skipping 33 matching lines @@
 // static
 AXPlatformNode* AXPlatformNodeAuraLinux::application_ = nullptr;
 
 // static
 void AXPlatformNodeAuraLinux::SetApplication(AXPlatformNode* application) {
   application_ = application;
   AtkUtilAuraLinux::GetInstance();
 }
 
 AtkRole AXPlatformNodeAuraLinux::GetAtkRole() {
+  GetWindowCoords();

[dmazzoni, 2015/03/27 19:09:14]

I don't think you need to call it here.

[shreeramk, 2015/03/28 16:59:48]

Sorry, by mistake I wrote this. :(

   switch (GetData().role) {
     case ui::AX_ROLE_ALERT:
       return ATK_ROLE_ALERT;
     case ui::AX_ROLE_APPLICATION:
       return ATK_ROLE_APPLICATION;
     case ui::AX_ROLE_BUTTON:
       return ATK_ROLE_PUSH_BUTTON;
     case ui::AX_ROLE_CHECK_BOX:
       return ATK_ROLE_CHECK_BOX;
     case ui::AX_ROLE_COMBO_BOX:
@@ skipping 81 matching lines @@
   return atk_object_;
 }
 
 void AXPlatformNodeAuraLinux::NotifyAccessibilityEvent(ui::AXEvent event_type) {
 }
 
 int AXPlatformNodeAuraLinux::GetIndexInParent() {
   return 0;
 }
 
+//
+// ax_platform_node_auralinux AtkComponent interface implementation.

[dmazzoni, 2015/03/27 19:09:14]

This belongs up above, just before the comment "The rest of the
AXPlatformNodeAuraLinux code"

+//
+
+static void ax_component_interface_get_extents(AtkComponent* atk_component,

[dmazzoni, 2015/03/27 19:09:14]

This should be named ax_platform_node_auralinux_get_extents for consistency.

+                                               gint* x, gint* y,
+                                               gint* width, gint* height,
+                                               AtkCoordType coord_type) {
+  *x = *y = *width = *height = 0;
+  AtkObject* atk_object = ATK_OBJECT(atk_component);
+  ui::AXPlatformNodeAuraLinux* obj =
+      AtkObjectToAXPlatformNodeAuraLinux(atk_object);
+  if (!obj)
+    return;
+
+  obj->GetExtents(x, y, width, height, coord_type);
+}
+
+static void ax_component_interface_get_position(AtkComponent* atk_component,
+                                                gint* x, gint* y,
+                                                AtkCoordType coord_type) {
+  *x = *y = 0;
+  AtkObject* atk_object = ATK_OBJECT(atk_component);
+  ui::AXPlatformNodeAuraLinux* obj =
+      AtkObjectToAXPlatformNodeAuraLinux(atk_object);
+  if (!obj)
+    return;
+
+  obj->GetPosition(x, y, coord_type);
+}
+
+static void ax_component_interface_get_size(AtkComponent* atk_component,
+                                            gint* width, gint* height) {
+  *width = *height = 0;
+  AtkObject* atk_object = ATK_OBJECT(atk_component);
+  ui::AXPlatformNodeAuraLinux* obj =
+      AtkObjectToAXPlatformNodeAuraLinux(atk_object);
+  if (!obj)
+    return;
+
+  obj->GetSize(width, height);
+}
+
+void ax_component_interface_base_init(AtkComponentIface* iface) {
+    iface->get_extents = ax_component_interface_get_extents;

[dmazzoni, 2015/03/27 19:09:14]

nit: only indent 2 chars

+    iface->get_position = ax_component_interface_get_position;
+    iface->get_size = ax_component_interface_get_size;
+}
+
+GType ax_component_auralinux_get_type() {

[dmazzoni, 2015/03/27 19:09:14]

Where is this called? I don't think we want a separate type for this.

[shreeramk, 2015/03/28 16:59:48]

Actually I don't know/understand like from where it'd be called or who would
call this. I asked this doubt in the last mail.

[dmazzoni, 2015/03/30 16:21:22]

This is what you do when you define a new type. What you want here is to add an
interface to an existing type using g_type_add_interface_static.

See my comment above, then delete this function.

+  static volatile gsize type_volatile = 0;
+
+  if (g_once_init_enter(&type_volatile)) {
+    static const GTypeInfo tinfo = {
+      sizeof(AtkComponentIface),
+      (GBaseInitFunc) ax_component_interface_base_init,
+      (GBaseFinalizeFunc) 0,
+    };
+
+    GType type = g_type_register_static(
+        ATK_TYPE_COMPONENT, "AtkComponent", &tinfo, GTypeFlags(0));
+    g_once_init_leave(&type_volatile, type);
+  }
+
+  return type_volatile;
+}
+
+void AXPlatformNodeAuraLinux::GetExtents(gint* x, gint* y,
+                                         gint* width, gint* height,
+                                         AtkCoordType coord_type) {
+  gfx::Rect extents = GetBoundsInScreen();
+
+  *x = extents.x();
+  *y = extents.y();
+  *width = extents.width();
+  *height = extents.height();
+
+  if (coord_type == ATK_XY_WINDOW) {
+    gfx::Rect window_coords = GetWindowCoords();
+    *x -= window_coords.x();
+    *y -= window_coords.y();
+    *width -= window_coords.width();
+    *height -= window_coords.height();

[shreeramk, 2015/03/27 16:09:13]

This calculation is is not required for width n height. Will update this in next
patch set.

+  }
+}
+
+void AXPlatformNodeAuraLinux::GetPosition(gint* x, gint* y,
+                                          AtkCoordType coord_type) {
+  gfx::Rect rect_pos = GetBoundsInScreen();
+
+  *x = rect_pos.x();
+  *y = rect_pos.y();
+
+  if (coord_type == ATK_XY_WINDOW) {
+    gfx::Rect window_coords = GetWindowCoords();
+    *x -= window_coords.x();
+    *y -= window_coords.y();
+  }
+}
+
+void AXPlatformNodeAuraLinux::GetSize(gint* width, gint* height) {
+  gfx::Rect rect_size = GetData().location;
+  *width = rect_size.width();
+  *height = rect_size.height();
+}
+
+gfx::Rect AXPlatformNodeAuraLinux::GetWindowCoords() {
+  AtkObject* parent = GetParent();
+
+  ui::AXPlatformNodeAuraLinux* obj =
+      AtkObjectToAXPlatformNodeAuraLinux(parent);

[dmazzoni, 2015/03/27 19:09:14]

You need to test this. It's possible that the parent is an AtkObject that isn't
an AXPlatformNodeAuraLinux object. You should work with it as an AtkObject.

[shreeramk, 2015/04/01 11:50:14]

Already a check is made in AtkObjectToAXPlatformNodeAuraLinux to check whether
its an IS_AX_PLATFORM_NODE_AURALINUX() object or not.

Do you mean to put a check like this

if(!obj)
   return.....

Or,

"You should work with it as an AtkObject."

Did you mean to say - direclty use it as an AtkObject?
But if I use it as an AtkObject then I won't be able to make below recursive
call
obj->GetWindowCoords();

[dmazzoni, 2015/04/01 15:31:16]

I think that's checking whether |this| is an AXPlatformNodeAuraLinux.

I'm saying that the parent may not be one.
That's right, I think you need to call a helper function that recursively walks
up the parents of an AtkObject and calls things like
ax_component_interface_get_position on it.

The situation you need to handle is that there's a GTK window, for example,
which has its own AtkObject, and this object is a child of that. You can't call
GetWindowCoords on the GTK window, but you can call
ax_component_interface_get_position on it.

+
+  if (atk_object_get_role(parent) == ATK_ROLE_WINDOW) {
+    gfx::Rect window_coords = obj->GetData().location;

[dmazzoni, 2015/03/27 19:09:14]

Do this using its AtkComponent interface

+    return window_coords;
+  }
+
+  return obj->GetWindowCoords();
+}
+
 }  // namespace ui