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[a11y] Ensure buffer is initialized before interacting with it (#11312)
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Adds a check before every UIA function call to ensure the terminal (specifically the buffer) is initialized before doing work. Both the `ScreenInfoUiaProvider` and the `UiaTextRange` are now covered.

## References
Closes #11135 
#10971 & #11042

## Detailed Description of the Pull Request / Additional comments
Originally, I tried applying this heuristic to all the `RuntimeClassInitialize` on `UiaTextRangeBase` with the philosophy of "a range pointing to an invalid buffer is invalid itself", but that caused a regression on [MSFT 33353327](https://microsoft.visualstudio.com/OS/_workitems/edit/33353327).

`IUiaData` also has `GetTextBuffer()` return a `TextBuffer&`, which cannot be checked for nullness. Instead, I decided to add a function to `IUiaData` that checks if we have a valid state. Since this is shared with Conhost and Conhost doesn't have this issue, I simply make that function say that it's always in a valid state.

## Validation Steps Performed
- [X] Narrator can detect newly created terminals
- [X] (On Windows Server 2022) Windows Terminal does not hang on launch
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@carlos-zamora
carlos-zamora committed Sep 23, 2021
1 parent aec7392 commit 8318bf9
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Showing 10 changed files with 83 additions and 69 deletions.
2 changes: 2 additions & 0 deletions src/Terminal.wprp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
<EventProvider Id="EventProvider_TerminalWin32Host" Name="56c06166-2e2e-5f4d-7ff3-74f4b78c87d6" />
<EventProvider Id="EventProvider_TerminalRemoting" Name="d6f04aad-629f-539a-77c1-73f5c3e4aa7b" />
<EventProvider Id="EventProvider_TerminalDirectX" Name="c93e739e-ae50-5a14-78e7-f171e947535d" />
<EventProvider Id="EventProvider_TerminalUIA" Name="e7ebce59-2161-572d-b263-2f16a6afb9e5"/>
<Profile Id="Terminal.Verbose.File" Name="Terminal" Description="Terminal" LoggingMode="File" DetailLevel="Verbose">
<Collectors>
<EventCollectorId Value="EventCollector_Terminal">
Expand All @@ -23,6 +24,7 @@
<EventProviderId Value="EventProvider_TerminalWin32Host" />
<EventProviderId Value="EventProvider_TerminalRemoting" />
<EventProviderId Value="EventProvider_TerminalDirectX" />
<EventProviderId Value="EventProvider_TerminalUIA" />
</EventProviders>
</EventCollectorId>
</Collectors>
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1 change: 1 addition & 0 deletions src/cascadia/TerminalCore/Terminal.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,7 @@ class Microsoft::Terminal::Core::Terminal final :
const COORD GetSelectionEnd() const noexcept override;
const std::wstring_view GetConsoleTitle() const noexcept override;
void ColorSelection(const COORD coordSelectionStart, const COORD coordSelectionEnd, const TextAttribute) override;
const bool IsUiaDataInitialized() const noexcept override;
#pragma endregion

void SetWriteInputCallback(std::function<void(std::wstring&)> pfn) noexcept;
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9 changes: 9 additions & 0 deletions src/cascadia/TerminalCore/terminalrenderdata.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -249,3 +249,12 @@ bool Terminal::IsScreenReversed() const noexcept
{
return _screenReversed;
}

const bool Terminal::IsUiaDataInitialized() const noexcept
{
// GH#11135: Windows Terminal needs to create and return an automation peer
// when a screen reader requests it. However, the terminal might not be fully
// initialized yet. So we use this to check if any crucial components of
// UiaData are not yet initialized.
return !!_buffer;
}
1 change: 1 addition & 0 deletions src/host/renderData.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -69,5 +69,6 @@ class RenderData final :
const COORD GetSelectionAnchor() const noexcept;
const COORD GetSelectionEnd() const noexcept;
void ColorSelection(const COORD coordSelectionStart, const COORD coordSelectionEnd, const TextAttribute attr);
const bool IsUiaDataInitialized() const noexcept override { return true; }
#pragma endregion
};
5 changes: 5 additions & 0 deletions src/host/ut_host/VtIoTests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -392,6 +392,11 @@ class MockRenderData : public IRenderData, IUiaData
{
}

const bool IsUiaDataInitialized() const noexcept
{
return true;
}

const std::wstring GetHyperlinkUri(uint16_t /*id*/) const noexcept
{
return {};
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1 change: 1 addition & 0 deletions src/types/IUiaData.h
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ namespace Microsoft::Console::Types
virtual const COORD GetSelectionAnchor() const noexcept = 0;
virtual const COORD GetSelectionEnd() const noexcept = 0;
virtual void ColorSelection(const COORD coordSelectionStart, const COORD coordSelectionEnd, const TextAttribute attr) = 0;
virtual const bool IsUiaDataInitialized() const noexcept = 0;
};

// See docs/virtual-dtors.md for an explanation of why this is weird.
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25 changes: 11 additions & 14 deletions src/types/ScreenInfoUiaProviderBase.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -220,21 +220,19 @@ IFACEMETHODIMP ScreenInfoUiaProviderBase::SetFocus()

IFACEMETHODIMP ScreenInfoUiaProviderBase::GetSelection(_Outptr_result_maybenull_ SAFEARRAY** ppRetVal)
{
RETURN_HR_IF_NULL(E_INVALIDARG, ppRetVal);
*ppRetVal = nullptr;

_LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_UnlockConsole();
});

RETURN_HR_IF_NULL(E_INVALIDARG, ppRetVal);
*ppRetVal = nullptr;
HRESULT hr = S_OK;
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// make a safe array
HRESULT hr = S_OK;
*ppRetVal = SafeArrayCreateVector(VT_UNKNOWN, 0, 1);
if (*ppRetVal == nullptr)
{
return E_OUTOFMEMORY;
}
RETURN_HR_IF_NULL(E_OUTOFMEMORY, *ppRetVal);

WRL::ComPtr<UiaTextRangeBase> range;
if (!_pData->IsSelectionActive())
Expand Down Expand Up @@ -272,19 +270,18 @@ IFACEMETHODIMP ScreenInfoUiaProviderBase::GetSelection(_Outptr_result_maybenull_

IFACEMETHODIMP ScreenInfoUiaProviderBase::GetVisibleRanges(_Outptr_result_maybenull_ SAFEARRAY** ppRetVal)
{
RETURN_HR_IF_NULL(E_INVALIDARG, ppRetVal);
*ppRetVal = nullptr;

_LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_UnlockConsole();
});

RETURN_HR_IF_NULL(E_INVALIDARG, ppRetVal);
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// make a safe array
*ppRetVal = SafeArrayCreateVector(VT_UNKNOWN, 0, 1);
if (*ppRetVal == nullptr)
{
return E_OUTOFMEMORY;
}
RETURN_HR_IF_NULL(E_OUTOFMEMORY, *ppRetVal);

WRL::ComPtr<UiaTextRangeBase> range;
const auto bufferSize = _pData->GetTextBuffer().GetSize();
Expand Down
14 changes: 6 additions & 8 deletions src/types/TermControlUiaProvider.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,21 +16,13 @@ HRESULT TermControlUiaProvider::RuntimeClassInitialize(_In_ ::Microsoft::Console
RETURN_IF_FAILED(ScreenInfoUiaProviderBase::RuntimeClassInitialize(uiaData));

_controlInfo = controlInfo;

// TODO GitHub #1914: Re-attach Tracing to UIA Tree
//Tracing::s_TraceUia(nullptr, ApiCall::Constructor, nullptr);
return S_OK;
}

IFACEMETHODIMP TermControlUiaProvider::Navigate(_In_ NavigateDirection direction,
_COM_Outptr_result_maybenull_ IRawElementProviderFragment** ppProvider) noexcept
{
RETURN_HR_IF_NULL(E_INVALIDARG, ppProvider);

// TODO GitHub #1914: Re-attach Tracing to UIA Tree
/*ApiMsgNavigate apiMsg;
apiMsg.Direction = direction;
Tracing::s_TraceUia(this, ApiCall::Navigate, &apiMsg);*/
*ppProvider = nullptr;

if (direction == NavigateDirection_Parent)
Expand Down Expand Up @@ -122,6 +114,12 @@ HRESULT TermControlUiaProvider::GetSelectionRange(_In_ IRawElementProviderSimple
RETURN_HR_IF_NULL(E_INVALIDARG, ppUtr);
*ppUtr = nullptr;

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized() || !_pData->IsSelectionActive());

const auto start = _pData->GetSelectionAnchor();

// we need to make end exclusive
Expand Down
14 changes: 0 additions & 14 deletions src/types/TermControlUiaTextRange.cpp
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Expand Up @@ -63,20 +63,6 @@ IFACEMETHODIMP TermControlUiaTextRange::Clone(_Outptr_result_maybenull_ ITextRan
return hr;
}

#if defined(_DEBUG) && defined(UiaTextRangeBase_DEBUG_MSGS)
OutputDebugString(L"Clone\n");
std::wstringstream ss;
ss << _id << L" cloned to " << (static_cast<UiaTextRangeBase*>(*ppRetVal))->_id;
std::wstring str = ss.str();
OutputDebugString(str.c_str());
OutputDebugString(L"\n");
#endif
// TODO GitHub #1914: Re-attach Tracing to UIA Tree
// tracing
/*ApiMsgClone apiMsg;
apiMsg.CloneId = static_cast<UiaTextRangeBase*>(*ppRetVal)->GetId();
Tracing::s_TraceUia(this, ApiCall::Clone, &apiMsg);*/

return S_OK;
}

Expand Down
80 changes: 47 additions & 33 deletions src/types/UiaTextRangeBase.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -220,15 +220,18 @@ IFACEMETHODIMP UiaTextRangeBase::CompareEndpoints(_In_ TextPatternRangeEndpoint
_Out_ int* pRetVal) noexcept
try
{
RETURN_HR_IF(E_INVALIDARG, pRetVal == nullptr);
RETURN_HR_IF_NULL(E_INVALIDARG, pRetVal);
*pRetVal = 0;

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// get the text range that we're comparing to
const UiaTextRangeBase* range = static_cast<UiaTextRangeBase*>(pTargetRange);
if (range == nullptr)
{
return E_INVALIDARG;
}
RETURN_HR_IF_NULL(E_INVALIDARG, range);

// get endpoint value that we're comparing to
const auto other = range->GetEndpoint(targetEndpoint);
Expand All @@ -240,10 +243,7 @@ try
// This is a temporary solution to comparing two UTRs from different TextBuffers
// Ensure both endpoints fit in the current buffer.
const auto bufferSize = _pData->GetTextBuffer().GetSize();
if (!bufferSize.IsInBounds(mine, true) || !bufferSize.IsInBounds(other, true))
{
return E_FAIL;
}
RETURN_HR_IF(E_FAIL, !bufferSize.IsInBounds(mine, true) || !bufferSize.IsInBounds(other, true));

// compare them
*pRetVal = bufferSize.CompareInBounds(mine, other, true);
Expand All @@ -259,6 +259,7 @@ IFACEMETHODIMP UiaTextRangeBase::ExpandToEnclosingUnit(_In_ TextUnit unit) noexc
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

try
{
Expand Down Expand Up @@ -446,6 +447,12 @@ try
RETURN_HR_IF(E_INVALIDARG, ppRetVal == nullptr);
*ppRetVal = nullptr;

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// AttributeIDs that require special handling
switch (attributeId)
{
Expand Down Expand Up @@ -607,6 +614,12 @@ try
RETURN_HR_IF(E_INVALIDARG, ppRetVal == nullptr);
*ppRetVal = nullptr;

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

const std::wstring queryText{ text, SysStringLen(text) };
const auto bufferSize = _getBufferSize();
const auto sensitivity = ignoreCase ? Search::Sensitivity::CaseInsensitive : Search::Sensitivity::CaseSensitive;
Expand Down Expand Up @@ -732,6 +745,12 @@ try
RETURN_HR_IF(E_INVALIDARG, pRetVal == nullptr);
VariantInit(pRetVal);

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// AttributeIDs that require special handling
switch (attributeId)
{
Expand Down Expand Up @@ -819,13 +838,14 @@ CATCH_RETURN();

IFACEMETHODIMP UiaTextRangeBase::GetBoundingRectangles(_Outptr_result_maybenull_ SAFEARRAY** ppRetVal) noexcept
{
RETURN_HR_IF(E_INVALIDARG, ppRetVal == nullptr);
*ppRetVal = nullptr;

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});

RETURN_HR_IF(E_INVALIDARG, ppRetVal == nullptr);
*ppRetVal = nullptr;
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

try
{
Expand Down Expand Up @@ -927,21 +947,19 @@ CATCH_RETURN();
IFACEMETHODIMP UiaTextRangeBase::GetText(_In_ int maxLength, _Out_ BSTR* pRetVal) noexcept
try
{
RETURN_HR_IF(E_INVALIDARG, pRetVal == nullptr);
RETURN_HR_IF_NULL(E_INVALIDARG, pRetVal);
RETURN_HR_IF(E_INVALIDARG, maxLength < -1);
*pRetVal = nullptr;

if (maxLength < -1)
{
return E_INVALIDARG;
}
_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

const auto maxLengthOpt = (maxLength == -1) ?
std::nullopt :
std::optional<unsigned int>{ maxLength };
_pData->LockConsole();
auto Unlock = wil::scope_exit([this]() noexcept {
_pData->UnlockConsole();
});
const auto text = _getTextValue(maxLengthOpt);
Unlock.reset();

Expand Down Expand Up @@ -1015,6 +1033,7 @@ try
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

const auto wasDegenerate = IsDegenerate();
if (count != 0)
Expand Down Expand Up @@ -1070,15 +1089,13 @@ IFACEMETHODIMP UiaTextRangeBase::MoveEndpointByUnit(_In_ TextPatternRangeEndpoin
{
RETURN_HR_IF(E_INVALIDARG, pRetVal == nullptr);
*pRetVal = 0;
if (count == 0)
{
return S_OK;
}

_pData->LockConsole();
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());
RETURN_HR_IF(S_OK, count == 0);

try
{
Expand Down Expand Up @@ -1116,21 +1133,16 @@ try
});

const UiaTextRangeBase* range = static_cast<UiaTextRangeBase*>(pTargetRange);
if (range == nullptr)
{
return E_INVALIDARG;
}
RETURN_HR_IF_NULL(E_INVALIDARG, range);
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

// TODO GH#5406: create a different UIA parent object for each TextBuffer
// This is a temporary solution to comparing two UTRs from different TextBuffers
// Ensure both endpoints fit in the current buffer.
const auto bufferSize = _pData->GetTextBuffer().GetSize();
const auto mine = GetEndpoint(endpoint);
const auto other = range->GetEndpoint(targetEndpoint);
if (!bufferSize.IsInBounds(mine, true) || !bufferSize.IsInBounds(other, true))
{
return E_FAIL;
}
RETURN_HR_IF(E_FAIL, !bufferSize.IsInBounds(mine, true) || !bufferSize.IsInBounds(other, true));

SetEndpoint(endpoint, range->GetEndpoint(targetEndpoint));

Expand All @@ -1146,6 +1158,7 @@ try
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

if (IsDegenerate())
{
Expand Down Expand Up @@ -1190,6 +1203,7 @@ try
auto Unlock = wil::scope_exit([&]() noexcept {
_pData->UnlockConsole();
});
RETURN_HR_IF(E_FAIL, !_pData->IsUiaDataInitialized());

const auto oldViewport = _pData->GetViewport().ToInclusive();
const auto viewportHeight = _getViewportHeight(oldViewport);
Expand Down

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@check-spelling-bot Report

Unrecognized words, please review:

  • apimswincoresynchl
  • comparand
  • cppm
  • intrin
  • ixx
  • MSAA
  • packagename
  • sdkddkver
  • SRWLOC
  • SRWLOCK
  • TLDR
  • wght
  • winsdkver
Previously acknowledged words that are now absent ADDB debounce FILETIME hpcon scprintf serializers testnetv Tlg VPrintf xIcon Xpath yIcon
To accept these unrecognized words as correct (and remove the previously acknowledged and now absent words), run the following commands

... in a clone of the git@github.com:microsoft/terminal.git repository
on the release-1.10 branch:

update_files() {
perl -e '
my @expect_files=qw('".github/actions/spelling/expect/alphabet.txt
.github/actions/spelling/expect/expect.txt
.github/actions/spelling/expect/web.txt"');
@ARGV=@expect_files;
my @stale=qw('"$patch_remove"');
my $re=join "|", @stale;
my $suffix=".".time();
my $previous="";
sub maybe_unlink { unlink($_[0]) if $_[0]; }
while (<>) {
if ($ARGV ne $old_argv) { maybe_unlink($previous); $previous="$ARGV$suffix"; rename($ARGV, $previous); open(ARGV_OUT, ">$ARGV"); select(ARGV_OUT); $old_argv = $ARGV; }
next if /^(?:$re)(?:(?:\r|\n)*$| .*)/; print;
}; maybe_unlink($previous);'
perl -e '
my $new_expect_file=".github/actions/spelling/expect/8318bf9a6add850e08fcbfc56ac9f34fc768dd7f.txt";
use File::Path qw(make_path);
use File::Basename qw(dirname);
make_path (dirname($new_expect_file));
open FILE, q{<}, $new_expect_file; chomp(my @words = <FILE>); close FILE;
my @add=qw('"$patch_add"');
my %items; @items{@words} = @words x (1); @items{@add} = @add x (1);
@words = sort {lc($a)."-".$a cmp lc($b)."-".$b} keys %items;
open FILE, q{>}, $new_expect_file; for my $word (@words) { print FILE "$word\n" if $word =~ /\w/; };
close FILE;
system("git", "add", $new_expect_file);
'
}

comment_json=$(mktemp)
curl -L -s -S \
  --header "Content-Type: application/json" \
  "https://api.github.com/repos/microsoft/terminal/comments/56978028" > "$comment_json"
comment_body=$(mktemp)
jq -r .body < "$comment_json" > $comment_body
rm $comment_json

patch_remove=$(perl -ne 'next unless s{^</summary>(.*)</details>$}{$1}; print' < "$comment_body")
  

patch_add=$(perl -e '$/=undef;
$_=<>;
s{<details>.*}{}s;
s{^#.*}{};
s{\n##.*}{};
s{(?:^|\n)\s*\*}{}g;
s{\s+}{ }g;
print' < "$comment_body")
  
update_files
rm $comment_body
git add -u
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⚠️ The command is written for posix shells. You can copy the contents of each perl command excluding the outer ' marks and dropping any '"/"' quotation mark pairs into a file and then run perl file.pl from the root of the repository to run the code. Alternatively, you can manually insert the items...

If the listed items are:

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If it relates to a ...

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See if there's a pattern that would match it.

If not, try writing one and adding it to a patterns/{file}.txt.

Patterns are Perl 5 Regular Expressions - you can test yours before committing to verify it will match your lines.

Note that patterns can't match multiline strings.

binary-ish string

Please add a file path to the excludes.txt file instead of just accepting the garbage.

File paths are Perl 5 Regular Expressions - you can test yours before committing to verify it will match your files.

^ refers to the file's path from the root of the repository, so ^README\.md$ would exclude README.md (on whichever branch you're using).

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