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Add set_value_multistring_nothrow for REG_MULTI_SZ writes #631

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Add set_value_multistring_nothrow for REG_MULTI_SZ writes #631

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36 changes: 36 additions & 0 deletions include/wil/registry.h
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Original file line number Diff line number Diff line change
Expand Up @@ -970,6 +970,42 @@ namespace reg
return ::wil::reg::set_value_expanded_string_nothrow(key, nullptr, value_name, data);
}

/**
* @brief Writes a REG_MULTI_SZ value from an array of null-terminated strings
* @param key An open or well-known registry key
* @param subkey The name of the subkey to append to `key`.
* If `nullptr`, then `key` is used without modification.
* @param value_name The name of the registry value whose data is to be updated.
* Can be nullptr to write to the unnamed default registry value.
* @param data An array of `count` null-terminated strings to write to the specified registry value.
* Each string is marshaled into a contiguous null-terminator-delimited multi-sz string.
* @param count The number of strings in `data`
* @return HRESULT error code indicating success or failure (does not throw C++ exceptions)
*/
inline HRESULT set_value_multistring_nothrow(
HKEY key, _In_opt_ PCWSTR subkey, _In_opt_ PCWSTR value_name, _In_reads_(count) const PCWSTR* data, size_t count) WI_NOEXCEPT
{
::wil::unique_process_heap_ptr<wchar_t> buffer;
DWORD bufferSizeBytes = 0;
RETURN_IF_FAILED(reg_view_details::get_multistring_from_strings_nothrow(data, count, buffer, &bufferSizeBytes));
return HRESULT_FROM_WIN32(::RegSetKeyValueW(key, subkey, value_name, REG_MULTI_SZ, buffer.get(), bufferSizeBytes));
}

/**
* @brief Writes a REG_MULTI_SZ value from an array of null-terminated strings
* @param key An open or well-known registry key
* @param value_name The name of the registry value whose data is to be updated.
* Can be nullptr to write to the unnamed default registry value.
* @param data An array of `count` null-terminated strings to write to the specified registry value.
* Each string is marshaled into a contiguous null-terminator-delimited multi-sz string.
* @param count The number of strings in `data`
* @return HRESULT error code indicating success or failure (does not throw C++ exceptions)
*/
inline HRESULT set_value_multistring_nothrow(HKEY key, _In_opt_ PCWSTR value_name, _In_reads_(count) const PCWSTR* data, size_t count) WI_NOEXCEPT
{
return ::wil::reg::set_value_multistring_nothrow(key, nullptr, value_name, data, count);
}

#if defined(__WIL_OBJBASE_H_) || defined(WIL_DOXYGEN)
/**
* @brief Writes raw bytes into a registry value under a specified key of the specified type
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64 changes: 64 additions & 0 deletions include/wil/registry_helpers.h
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Expand Up @@ -237,6 +237,70 @@ namespace reg
}
#endif

/**
* @brief A nothrow translation function marshaling an array of null-terminated strings into a contiguous
* null-terminator-delimited REG_MULTI_SZ buffer allocated on the process heap.
* @param data An array of `count` null-terminated strings to marshal into a multi-sz buffer
* @param count The number of strings in `data`
* @param buffer Receives ownership of the process-heap-allocated wchar_t buffer on success
* @param bufferSizeBytes Receives the size, in bytes, of the marshaled buffer (including terminators)
* @return HRESULT error code indicating success or failure (does not throw C++ exceptions)
*/
inline HRESULT get_multistring_from_strings_nothrow(
_In_reads_(count) const PCWSTR* data, size_t count, ::wil::unique_process_heap_ptr<wchar_t>& buffer, _Out_ DWORD* bufferSizeBytes) WI_NOEXCEPT
{
buffer.reset();
*bufferSizeBytes = 0;

size_t total_size_chars = 1; // final terminator
for (size_t i = 0; i < count; ++i)
{
const size_t entry_chars = ::wcslen(data[i]) + 1;
if (total_size_chars + entry_chars < total_size_chars)
{
return E_INVALIDARG; // integer overflow
}
total_size_chars += entry_chars;
}

if (count == 0)
{
// An empty multi-string still requires a leading null plus the final terminator.
total_size_chars = 2;
}

if (total_size_chars > (MAXDWORD / sizeof(wchar_t)))
{
return E_INVALIDARG;
}
const size_t total_size_bytes = total_size_chars * sizeof(wchar_t);

::wil::unique_process_heap_ptr<wchar_t> result{static_cast<wchar_t*>(::HeapAlloc(::GetProcessHeap(), 0, total_size_bytes))};
RETURN_IF_NULL_ALLOC(result.get());

size_t offset = 0;
for (size_t i = 0; i < count; ++i)
{
// Each string is null-terminated and it is valid to read that null character, so copy length + 1
// characters to include the terminator in a single memcpy.
const size_t entry_chars = ::wcslen(data[i]) + 1;
memcpy(result.get() + offset, data[i], entry_chars * sizeof(wchar_t));
offset += entry_chars;
}

if (count == 0)
{
result.get()[offset++] = L'\0'; // leading null for an empty multi-string
}

result.get()[offset++] = L'\0'; // final terminator
WI_ASSERT(offset == total_size_chars);

buffer = wistd::move(result);
*bufferSizeBytes = static_cast<DWORD>(total_size_bytes);
return S_OK;
}

#if defined(__WIL_OBJBASE_H_)
template <size_t C>
void get_multistring_bytearray_from_strings_nothrow(const PCWSTR data[C], ::wil::unique_cotaskmem_array_ptr<BYTE>& multistring) WI_NOEXCEPT
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121 changes: 121 additions & 0 deletions tests/RegistryTests.cpp
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Expand Up @@ -3181,6 +3181,127 @@ TEST_CASE("BasicRegistryTests::multi-strings", "[registry]")
}
#endif
#endif

#if WIL_USE_STL && defined(WIL_ENABLE_EXCEPTIONS)
const auto to_ptrs = [](const std::vector<std::wstring>& strings) {
std::vector<PCWSTR> ptrs;
ptrs.reserve(strings.size());
for (const auto& s : strings)
{
ptrs.push_back(s.c_str());
}
return ptrs;
};

SECTION("set_value_multistring_nothrow/get_value_multistring_nothrow: with open key")
{
wil::unique_hkey hkey;
REQUIRE_SUCCEEDED(wil::reg::create_unique_key_nothrow(HKEY_CURRENT_USER, testSubkey, hkey, wil::reg::key_access::readwrite));

for (const auto& value : multiStringTestVector)
{
const auto ptrs = to_ptrs(value);
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(hkey.get(), stringValueName, ptrs.data(), ptrs.size()));
auto result = wil::reg::get_value_multistring(hkey.get(), stringValueName);
// set_value_multistring_nothrow should produce the same result as set_value_multistring
wil::reg::set_value_multistring(hkey.get(), multiStringValueName, value);
auto expected = wil::reg::get_value_multistring(hkey.get(), multiStringValueName);
REQUIRE(result == expected);
}

// and verify default value name
const std::vector<std::wstring> testValue{L"hello", L"world"};
const auto testPtrs = to_ptrs(testValue);
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(hkey.get(), nullptr, testPtrs.data(), testPtrs.size()));
auto result = wil::reg::get_value_multistring(hkey.get(), nullptr);
REQUIRE(result == testValue);
}

SECTION("set_value_multistring_nothrow/get_value_multistring_nothrow: with string key")
{
for (const auto& value : multiStringTestVector)
{
const auto ptrs = to_ptrs(value);
REQUIRE_SUCCEEDED(
wil::reg::set_value_multistring_nothrow(HKEY_CURRENT_USER, testSubkey, stringValueName, ptrs.data(), ptrs.size()));
auto result = wil::reg::get_value_multistring(HKEY_CURRENT_USER, testSubkey, stringValueName);
// set_value_multistring_nothrow should produce the same result as set_value_multistring
wil::reg::set_value_multistring(HKEY_CURRENT_USER, testSubkey, multiStringValueName, value);
auto expected = wil::reg::get_value_multistring(HKEY_CURRENT_USER, testSubkey, multiStringValueName);
REQUIRE(result == expected);
}

// and verify default value name
const std::vector<std::wstring> testValue{L"hello", L"world"};
const auto testPtrs = to_ptrs(testValue);
REQUIRE_SUCCEEDED(
wil::reg::set_value_multistring_nothrow(HKEY_CURRENT_USER, testSubkey, nullptr, testPtrs.data(), testPtrs.size()));
auto result = wil::reg::get_value_multistring(HKEY_CURRENT_USER, testSubkey, nullptr);
REQUIRE(result == testValue);
}

SECTION("set_value_multistring_nothrow: empty array with open key")
{
wil::unique_hkey hkey;
REQUIRE_SUCCEEDED(wil::reg::create_unique_key_nothrow(HKEY_CURRENT_USER, testSubkey, hkey, wil::reg::key_access::readwrite));

// When passed an empty array, set_value_multistring_nothrow writes 2 null-terminators
// (i.e. a single empty string), matching the behavior of set_value_multistring
const std::vector<std::wstring> arrayOfOne{L""};
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(hkey.get(), stringValueName, nullptr, 0));
auto result = wil::reg::get_value_multistring(hkey.get(), stringValueName);
REQUIRE(result == arrayOfOne);

// and verify default value name
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(hkey.get(), nullptr, nullptr, 0));
result = wil::reg::get_value_multistring(hkey.get(), nullptr);
REQUIRE(result == arrayOfOne);
}

SECTION("set_value_multistring_nothrow: empty array with string key")
{
const std::vector<std::wstring> arrayOfOne{L""};
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(HKEY_CURRENT_USER, testSubkey, stringValueName, nullptr, 0));
auto result = wil::reg::get_value_multistring(HKEY_CURRENT_USER, testSubkey, stringValueName);
REQUIRE(result == arrayOfOne);

// and verify default value name
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(HKEY_CURRENT_USER, testSubkey, nullptr, nullptr, 0));
result = wil::reg::get_value_multistring(HKEY_CURRENT_USER, testSubkey, nullptr);
REQUIRE(result == arrayOfOne);
}

SECTION("set_value_multistring_nothrow: fails with E_ACCESSDENIED on read-only key")
{
wil::unique_hkey hkey;
REQUIRE_SUCCEEDED(wil::reg::create_unique_key_nothrow(HKEY_CURRENT_USER, testSubkey, hkey, wil::reg::key_access::readwrite));

wil::unique_hkey readOnlyKey;
REQUIRE_SUCCEEDED(wil::reg::open_unique_key_nothrow(HKEY_CURRENT_USER, testSubkey, readOnlyKey, wil::reg::key_access::read));

const PCWSTR testValue[]{L"test"};
auto hr = wil::reg::set_value_multistring_nothrow(readOnlyKey.get(), stringValueName, testValue, ARRAYSIZE(testValue));
REQUIRE(hr == E_ACCESSDENIED);
}

SECTION("set_value_multistring_nothrow: round-trip with nothrow get via cotaskmem")
{
wil::unique_hkey hkey;
REQUIRE_SUCCEEDED(wil::reg::create_unique_key_nothrow(HKEY_CURRENT_USER, testSubkey, hkey, wil::reg::key_access::readwrite));

const PCWSTR testValue[]{L"alpha", L"bravo", L"charlie"};
REQUIRE_SUCCEEDED(wil::reg::set_value_multistring_nothrow(hkey.get(), stringValueName, testValue, ARRAYSIZE(testValue)));

#if defined(__WIL_OBJBASE_H_)
wil::unique_cotaskmem_array_ptr<wil::unique_cotaskmem_string> result{};
REQUIRE_SUCCEEDED(wil::reg::get_value_multistring_nothrow(hkey.get(), stringValueName, result));
REQUIRE(result.size() == 3);
REQUIRE(std::wstring_view(result[0]) == L"alpha");
REQUIRE(std::wstring_view(result[1]) == L"bravo");
REQUIRE(std::wstring_view(result[2]) == L"charlie");
#endif // defined(__WIL_OBJBASE_H_)
}
#endif // WIL_USE_STL && defined(WIL_ENABLE_EXCEPTIONS)
}

#if defined(__WIL_OBJBASE_H_)
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