ladybird/Tests/AK/CMakeLists.txt
Andreas Kling a3e82eaad3 AK: Introduce the new String, replacement for DeprecatedString
DeprecatedString (formerly String) has been with us since the start,
and it has served us well. However, it has a number of shortcomings
that I'd like to address.

Some of these issues are hard if not impossible to solve incrementally
inside of DeprecatedString, so instead of doing that, let's build a new
String class and then incrementally move over to it instead.

Problems in DeprecatedString:

- It assumes string allocation never fails. This makes it impossible
  to use in allocation-sensitive contexts, and is the reason we had to
  ban DeprecatedString from the kernel entirely.

- The awkward null state. DeprecatedString can be null. It's different
  from the empty state, although null strings are considered empty.
  All code is immediately nicer when using Optional<DeprecatedString>
  but DeprecatedString came before Optional, which is how we ended up
  like this.

- The encoding of the underlying data is ambiguous. For the most part,
  we use it as if it's always UTF-8, but there have been cases where
  we pass around strings in other encodings (e.g ISO8859-1)

- operator[] and length() are used to iterate over DeprecatedString one
  byte at a time. This is done all over the codebase, and will *not*
  give the right results unless the string is all ASCII.

How we solve these issues in the new String:

- Functions that may allocate now return ErrorOr<String> so that ENOMEM
  errors can be passed to the caller.

- String has no null state. Use Optional<String> when needed.

- String is always UTF-8. This is validated when constructing a String.
  We may need to add a bypass for this in the future, for cases where
  you have a known-good string, but for now: validate all the things!

- There is no operator[] or length(). You can get the underlying data
  with bytes(), but for iterating over code points, you should be using
  an UTF-8 iterator.

Furthermore, it has two nifty new features:

- String implements a small string optimization (SSO) for strings that
  can fit entirely within a pointer. This means up to 3 bytes on 32-bit
  platforms, and 7 bytes on 64-bit platforms. Such small strings will
  not be heap-allocated.

- String can create substrings without making a deep copy of the
  substring. Instead, the superstring gets +1 refcount from the
  substring, and it acts like a view into the superstring. To make
  substrings like this, use the substring_with_shared_superstring() API.

One caveat:

- String does not guarantee that the underlying data is null-terminated
  like DeprecatedString does today. While this was nifty in a handful of
  places where we were calling C functions, it did stand in the way of
  shared-superstring substrings.
2022-12-06 15:21:26 +01:00

86 lines
1.9 KiB
CMake

set(AK_TEST_SOURCES
TestFixedPoint.cpp
TestAllOf.cpp
TestAnyOf.cpp
TestArbitrarySizedEnum.cpp
TestArray.cpp
TestAtomic.cpp
TestBadge.cpp
TestBase64.cpp
TestBinaryHeap.cpp
TestBinarySearch.cpp
TestBitCast.cpp
TestBitmap.cpp
TestBuiltinWrappers.cpp
TestByteBuffer.cpp
TestCharacterTypes.cpp
TestChecked.cpp
TestCircularDeque.cpp
TestCircularDuplexStream.cpp
TestCircularQueue.cpp
TestComplex.cpp
TestDeprecatedString.cpp
TestDisjointChunks.cpp
TestDistinctNumeric.cpp
TestDoublyLinkedList.cpp
TestEndian.cpp
TestEnumBits.cpp
TestFind.cpp
TestFixedArray.cpp
TestFloatingPoint.cpp
TestFloatingPointParsing.cpp
TestFormat.cpp
TestGenericLexer.cpp
TestHashFunctions.cpp
TestHashMap.cpp
TestHashTable.cpp
TestHex.cpp
TestIPv4Address.cpp
TestIPv6Address.cpp
TestIndexSequence.cpp
TestIntegerMath.cpp
TestIntrusiveList.cpp
TestIntrusiveRedBlackTree.cpp
TestJSON.cpp
TestLEB128.cpp
TestLexicalPath.cpp
TestMACAddress.cpp
TestMemory.cpp
TestMemoryStream.cpp
TestNeverDestroyed.cpp
TestNonnullRefPtr.cpp
TestNumberFormat.cpp
TestOptional.cpp
TestPrint.cpp
TestQueue.cpp
TestQuickSort.cpp
TestRedBlackTree.cpp
TestRefPtr.cpp
TestSinglyLinkedList.cpp
TestSourceGenerator.cpp
TestSourceLocation.cpp
TestSpan.cpp
TestStack.cpp
TestStdLibExtras.cpp
TestString.cpp
TestStringFloatingPointConversions.cpp
TestStringUtils.cpp
TestStringView.cpp
TestTime.cpp
TestTrie.cpp
TestTuple.cpp
TestTypeTraits.cpp
TestTypedTransfer.cpp
TestUFixedBigInt.cpp
TestURL.cpp
TestUtf16.cpp
TestUtf8.cpp
TestVariant.cpp
TestVector.cpp
TestWeakPtr.cpp
)
foreach(source IN LISTS AK_TEST_SOURCES)
serenity_test("${source}" AK)
endforeach()