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authorMichael Weghorn <m.weghorn@posteo.de>2022-09-02 13:06:08 +0200
committerMichael Weghorn <m.weghorn@posteo.de>2022-09-02 15:47:37 +0200
commit206543c7bef58fc559852553a3b2faba0b604259 (patch)
tree4fc3e0e57e6f9b50e276998fc04241035a2dffb6 /comphelper
parent38671e21d7dbcd5019912b9468305018de0c922e (diff)
[API CHANGE] tdf#150683 a11y: Switch a11y child index to 64 bit
With 16k column support in Calc enabled by default in commit 4c5f8ccf0a2320432b8fe91add1dcadf54d9fd58 Date: Tue Mar 8 12:44:49 2022 +0100 change default Calc number of columns to 16384 (tdf#50916) , the number of Calc cells in a spreadsheet is larger than SAL_MAX_INT32, meaning that a 32-bit a11y child index is no more enough and using it resulted in integer overflows in methods handling corresponding Calc cells in the a11y layer. This e.g. had the effect of the Orca and NVDA screen readers not announcing focused or selected cells properly when their a11y child index was out of the 32-bit integer range. Switch the internal a11y child indices to 64 bit to be able to handle this properly internally. Since the platform APIs (at least AT-SPI on Linux and IAccessible2 on Windows; from what I can see LO's macOS a11y bridge doesn't directly expose the child index) are still restricted to 32 bit, larger child indices still cannot be exposed via the platform APIs. As a consequence, use of the the IAccessible2 and AT-SPI methods that use the child index remains problematic in those cases where the child index is larger. However, as an alternative to using the AT-SPI Table interface and the IAccessibleTable/ IAccessibleTable2 interfaces with the child index to retrieve information about a specific cell, both AT-SPI and IAccessible2 also provide interfaces to retrieve that information directly from the cell object (TableCell interface for AT-SPI, IAccessibleTableCell for IAccessible2). Those interfaces are already implemented/exposed for winaccessibility (s. `CAccTable`) and the qt5/qt6/kf5 VCL plugins (s. the `QAccessibleTableCellInterface` methods implemented in `QtAccessibleInterface`). With the switch to 64-bit internal a11y child indices, these now behave correctly for cells with a child index that doesn't fit into 32 bit as well. NVDA on Windows already uses the IAccessibleTableCell interface and thus announcing focused cells works fine with this change in place. Orca on Linux currently doesn't make use of the AT-SPI TableCell interface yet, but with a suggested change to do so [1], announcement of selected cells works with the qt6 VCL plugin with a current qtbase dev branch as well - when combined with the suggested changes to implement support for the AT-SPI TableCell interface in Qt [2] [3] and the LO change based on that [4] and a fix for a nullptr dereference [5]. The gtk3 VCL plugin doesn't expose the AT-SPI TableCell interface yet, but once it does so (via `AtkTableCell`), it also works with the suggested Orca change [1] in place. (Adding that is planned for an upcoming change, works with a local WIP patch.) For handling return values that are larger than what platform APIs support, the following approach has been chosen for now: 1) When the return value is for the count of (selected) children, the maximum value N supported by the platform API is returned. (This is what `ScAccessibleTableBase::getAccessibleChildCount` did previously.) The first N elements can be accessed by their actual (selection) indices. 2) When the return value is the child/cell index, -2 is returned for objects whose index is greater than the maximum value supported by the platform API. Using a non-negative value would mean that the index would refer to *another* actually existing child. A child index of -1 on the other hand tends to be interpreted as "child is invalid" or "object isn't actually a child of its (previous) parent any more)". For the Orca case, this would result in objects with a child index of -1 not being announced, as they are considered "zombies" [6]. What's still somewhat problematic is the case where more than 2^31 children are *selected*, since access to those children still happens by the index into the selection in the platform APIs, and not all selected items are accessible this way. (Screen readers usually just retrieve the first and last element from the selection and announce those.) Orca already seems to apply different handling for the case for fully selected rows and columns, so "All cells selected" or "Columns ... to ... selected" is announced just fine even if more than 2^31 cells are selected. (Side note: While Microsoft User Interface Automation - UIA - also uses 32-bit indices, it also has specific methods in the ISelectionProvider2 interface that allow to explicitly retrieve the first and last selected item, `ISelectionProvider2::get_FirstSelectedItem` and `ISelectionProvider2::get_LastSelectedItem`, but we currently don't support UIA on Windows.) Bound checks at the beginning of the methods from the `XAccessibleContext`, `XAccessibleSelection` and `XAccessibleTable` interfaces that take a child index (or in helper methods called by those) should generally already prevent too large indices from being passed to the methods in the lower layer code that take smaller integer types. Such bound checking has been been added in various places where it wasn't present yet. If there any remaining issues of this kind that show after this commit, they can probably be solved in a similar way (s.e.g. the change to `AccessibleBrowseBox::getAccessibleChild` in this commit). A few asserts were also added at places where my understanding is that values shouldn't be larger than what is supported by a called method anyway. A test case will be added in a following change. [1] https://gitlab.gnome.org/GNOME/orca/-/merge_requests/131 [2] https://codereview.qt-project.org/c/qt/qtbase/+/428566 [3] https://codereview.qt-project.org/c/qt/qtbase/+/428567 [4] https://gerrit.libreoffice.org/c/core/+/138750 [5] https://codereview.qt-project.org/c/qt/qtbase/+/430157 [6] https://gitlab.gnome.org/GNOME/orca/-/blob/82c8542002e36e0d3d918088d583162d25136143/src/orca/script_utilities.py#L5155 Change-Id: I3af590c988b0e6754fc72545918412f39e8fea07 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/139258 Tested-by: Jenkins Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Diffstat (limited to 'comphelper')
-rw-r--r--comphelper/source/misc/accessiblecontexthelper.cxx8
-rw-r--r--comphelper/source/misc/accessibleselectionhelper.cxx26
-rw-r--r--comphelper/source/misc/accessiblewrapper.cxx10
3 files changed, 22 insertions, 22 deletions
diff --git a/comphelper/source/misc/accessiblecontexthelper.cxx b/comphelper/source/misc/accessiblecontexthelper.cxx
index ad2c63b1a1c0..854b3966036e 100644
--- a/comphelper/source/misc/accessiblecontexthelper.cxx
+++ b/comphelper/source/misc/accessiblecontexthelper.cxx
@@ -171,12 +171,12 @@ namespace comphelper
}
- sal_Int32 SAL_CALL OAccessibleContextHelper::getAccessibleIndexInParent( )
+ sal_Int64 SAL_CALL OAccessibleContextHelper::getAccessibleIndexInParent( )
{
OExternalLockGuard aGuard( this );
// -1 for child not found/no parent (according to specification)
- sal_Int32 nRet = -1;
+ sal_Int64 nRet = -1;
try
{
@@ -198,8 +198,8 @@ namespace comphelper
if ( xCreator.is() )
{
- sal_Int32 nChildCount = xParentContext->getAccessibleChildCount();
- for ( sal_Int32 nChild = 0; ( nChild < nChildCount ) && ( -1 == nRet ); ++nChild )
+ sal_Int64 nChildCount = xParentContext->getAccessibleChildCount();
+ for ( sal_Int64 nChild = 0; ( nChild < nChildCount ) && ( -1 == nRet ); ++nChild )
{
Reference< XAccessible > xChild( xParentContext->getAccessibleChild( nChild ) );
if ( xChild.get() == xCreator.get() )
diff --git a/comphelper/source/misc/accessibleselectionhelper.cxx b/comphelper/source/misc/accessibleselectionhelper.cxx
index 967c1b079e48..97b75115e5e6 100644
--- a/comphelper/source/misc/accessibleselectionhelper.cxx
+++ b/comphelper/source/misc/accessibleselectionhelper.cxx
@@ -36,13 +36,13 @@ namespace comphelper
OCommonAccessibleSelection::~OCommonAccessibleSelection() {}
- void OCommonAccessibleSelection::selectAccessibleChild( sal_Int32 nChildIndex )
+ void OCommonAccessibleSelection::selectAccessibleChild( sal_Int64 nChildIndex )
{
implSelect( nChildIndex, true );
}
- bool OCommonAccessibleSelection::isAccessibleChildSelected( sal_Int32 nChildIndex )
+ bool OCommonAccessibleSelection::isAccessibleChildSelected( sal_Int64 nChildIndex )
{
return implIsSelected( nChildIndex );
}
@@ -60,16 +60,16 @@ namespace comphelper
}
- sal_Int32 OCommonAccessibleSelection::getSelectedAccessibleChildCount( )
+ sal_Int64 OCommonAccessibleSelection::getSelectedAccessibleChildCount( )
{
- sal_Int32 nRet = 0;
+ sal_Int64 nRet = 0;
Reference< XAccessibleContext > xParentContext( implGetAccessibleContext() );
OSL_ENSURE( xParentContext.is(), "OCommonAccessibleSelection::getSelectedAccessibleChildCount: no parent context!" );
if( xParentContext.is() )
{
- for( sal_Int32 i = 0, nChildCount = xParentContext->getAccessibleChildCount(); i < nChildCount; i++ )
+ for( sal_Int64 i = 0, nChildCount = xParentContext->getAccessibleChildCount(); i < nChildCount; i++ )
if( implIsSelected( i ) )
++nRet;
}
@@ -78,7 +78,7 @@ namespace comphelper
}
- Reference< XAccessible > OCommonAccessibleSelection::getSelectedAccessibleChild( sal_Int32 nSelectedChildIndex )
+ Reference< XAccessible > OCommonAccessibleSelection::getSelectedAccessibleChild( sal_Int64 nSelectedChildIndex )
{
Reference< XAccessible > xRet;
Reference< XAccessibleContext > xParentContext( implGetAccessibleContext() );
@@ -87,7 +87,7 @@ namespace comphelper
if( xParentContext.is() )
{
- for( sal_Int32 i = 0, nChildCount = xParentContext->getAccessibleChildCount(), nPos = 0; ( i < nChildCount ) && !xRet.is(); i++ )
+ for( sal_Int64 i = 0, nChildCount = xParentContext->getAccessibleChildCount(), nPos = 0; ( i < nChildCount ) && !xRet.is(); i++ )
if( implIsSelected( i ) && ( nPos++ == nSelectedChildIndex ) )
xRet = xParentContext->getAccessibleChild( i );
}
@@ -96,7 +96,7 @@ namespace comphelper
}
- void OCommonAccessibleSelection::deselectAccessibleChild( sal_Int32 nSelectedChildIndex )
+ void OCommonAccessibleSelection::deselectAccessibleChild( sal_Int64 nSelectedChildIndex )
{
implSelect( nSelectedChildIndex, false );
}
@@ -117,14 +117,14 @@ namespace comphelper
}
- void SAL_CALL OAccessibleSelectionHelper::selectAccessibleChild( sal_Int32 nChildIndex )
+ void SAL_CALL OAccessibleSelectionHelper::selectAccessibleChild( sal_Int64 nChildIndex )
{
OExternalLockGuard aGuard( this );
OCommonAccessibleSelection::selectAccessibleChild( nChildIndex );
}
- sal_Bool SAL_CALL OAccessibleSelectionHelper::isAccessibleChildSelected( sal_Int32 nChildIndex )
+ sal_Bool SAL_CALL OAccessibleSelectionHelper::isAccessibleChildSelected( sal_Int64 nChildIndex )
{
OExternalLockGuard aGuard( this );
return OCommonAccessibleSelection::isAccessibleChildSelected( nChildIndex );
@@ -145,21 +145,21 @@ namespace comphelper
}
- sal_Int32 SAL_CALL OAccessibleSelectionHelper::getSelectedAccessibleChildCount( )
+ sal_Int64 SAL_CALL OAccessibleSelectionHelper::getSelectedAccessibleChildCount( )
{
OExternalLockGuard aGuard( this );
return OCommonAccessibleSelection::getSelectedAccessibleChildCount();
}
- Reference< XAccessible > SAL_CALL OAccessibleSelectionHelper::getSelectedAccessibleChild( sal_Int32 nSelectedChildIndex )
+ Reference< XAccessible > SAL_CALL OAccessibleSelectionHelper::getSelectedAccessibleChild( sal_Int64 nSelectedChildIndex )
{
OExternalLockGuard aGuard( this );
return OCommonAccessibleSelection::getSelectedAccessibleChild( nSelectedChildIndex );
}
- void SAL_CALL OAccessibleSelectionHelper::deselectAccessibleChild( sal_Int32 nSelectedChildIndex )
+ void SAL_CALL OAccessibleSelectionHelper::deselectAccessibleChild( sal_Int64 nSelectedChildIndex )
{
OExternalLockGuard aGuard( this );
OCommonAccessibleSelection::deselectAccessibleChild( nSelectedChildIndex );
diff --git a/comphelper/source/misc/accessiblewrapper.cxx b/comphelper/source/misc/accessiblewrapper.cxx
index c99aec3a9067..af5cd50a378b 100644
--- a/comphelper/source/misc/accessiblewrapper.cxx
+++ b/comphelper/source/misc/accessiblewrapper.cxx
@@ -388,13 +388,13 @@ namespace comphelper
IMPLEMENT_FORWARD_XTYPEPROVIDER2( OAccessibleContextWrapperHelper, OComponentProxyAggregationHelper, OAccessibleContextWrapperHelper_Base )
- sal_Int32 OAccessibleContextWrapperHelper::baseGetAccessibleChildCount( )
+ sal_Int64 OAccessibleContextWrapperHelper::baseGetAccessibleChildCount( )
{
return m_xInnerContext->getAccessibleChildCount();
}
- Reference< XAccessible > OAccessibleContextWrapperHelper::baseGetAccessibleChild( sal_Int32 i )
+ Reference< XAccessible > OAccessibleContextWrapperHelper::baseGetAccessibleChild( sal_Int64 i )
{
// get the child of the wrapped component
Reference< XAccessible > xInnerChild = m_xInnerContext->getAccessibleChild( i );
@@ -494,13 +494,13 @@ namespace comphelper
}
- sal_Int32 SAL_CALL OAccessibleContextWrapper::getAccessibleChildCount( )
+ sal_Int64 SAL_CALL OAccessibleContextWrapper::getAccessibleChildCount( )
{
return baseGetAccessibleChildCount();
}
- Reference< XAccessible > SAL_CALL OAccessibleContextWrapper::getAccessibleChild( sal_Int32 i )
+ Reference< XAccessible > SAL_CALL OAccessibleContextWrapper::getAccessibleChild( sal_Int64 i )
{
return baseGetAccessibleChild( i );
}
@@ -512,7 +512,7 @@ namespace comphelper
}
- sal_Int32 SAL_CALL OAccessibleContextWrapper::getAccessibleIndexInParent( )
+ sal_Int64 SAL_CALL OAccessibleContextWrapper::getAccessibleIndexInParent( )
{
return m_xInnerContext->getAccessibleIndexInParent();
}