Problem:
- `typedef` is a keyword which comes from C and carries with it old
syntax that is hard to read.
- Creating type aliases with the `using` keyword allows for easier
future maintenance because it supports template syntax.
- There is inconsistent use of `typedef` vs `using`.
Solution:
- Use `clang-tidy`'s checker called `modernize-use-using` to update
the syntax to use the newer syntax.
- Remove unused functions to make `clang-tidy` happy.
- This results in consistency within the codebase.
Problem:
- Building with clang is broken because of the `struct` vs `class`
mismatch between the definition and declaration.
Solution:
- Change `class` to `struct` in the forward declaration.
Problem:
- IPv4Address class cannot be used in a compile-time context.
- A union is used by initializing one of the members and reading the
non-active member. This is undefined behavior and not permitted in a
`constexpr` context.
Solution:
- Eliminate undefined behavior by changing to a simple `u32` for
storage instead of the union and performing mask/shift calculations
for obtaining the individual octets.
- Decorate functions with `constexpr` where possible. Currently string
formatting and optionals are not `constexpr`-capable so functions
using those are left out.
- Modify tests to validate functionality in a `constexpr` context in
addition to the run-time tests already being run. This ensures that
functionality is the same in both contexts.
This makes most operations thread safe, especially so that they
can safely be used in the Kernel. This includes obtaining a strong
reference from a weak reference, which now requires an explicit
call to WeakPtr::strong_ref(). Another major change is that
Weakable::make_weak_ref() may require the explicit target type.
Previously we used reinterpret_cast in WeakPtr, assuming that it
can be properly converted. But WeakPtr does not necessarily have
the knowledge to be able to do this. Instead, we now ask the class
itself to deliver a WeakPtr to the type that we want.
Also, WeakLink is no longer specific to a target type. The reason
for this is that we want to be able to safely convert e.g. WeakPtr<T>
to WeakPtr<U>, and before this we just reinterpret_cast the internal
WeakLink<T> to WeakLink<U>, which is a bold assumption that it would
actually produce the correct code. Instead, WeakLink now operates
on just a raw pointer and we only make those constructors/operators
available if we can verify that it can be safely cast.
In order to guarantee thread safety, we now use the least significant
bit in the pointer for locking purposes. This also means that only
properly aligned pointers can be used.
Problem:
- There is no direct unit testing of the IPv4Address functionality
which makes refactoring difficult.
Solution:
- Add unit tests to cover the current functionality of
IPv4Address. This will allow future refactorings with confidence.
We had competing inline definitions of the placement operators new.
Avoid this by having <AK/kmalloc.h> pull in <new> from the compiler
and always using their definitions instead.
I feel like there must be an elegant solution to this whole situation
with the operators, but I'm not sure what it is.
`AK::URL` will now check if the URL requires a port to be set using
`AK::URL.protocol_requires_port(protocol)`.
If the URL does not specify a port, and no default port for the URL
protocol is found with `AK::URL.default_port_for_protocol(protocol)`,
the URL is considered to be invalid.
This looks at three things:
- if the type has a typedef `AllowOwnPtr', respect that
- if not, disallow construction if both of `ref()' and `unref()' are
present.
Note that in the second case, if a type only defines `ref()' or only
defines `unref()', an OwnPtr can be created, as a RefPtr of that type
would be ill-formed.
Also marks a `Performance' to explicitly allow OwnPtrs.
This allows going back one character at a time, and then re-consume
previously consumed chars.
The code I need this for looks something like this:
ASSERT(lexer.consume_specific('\\'));
if (lexer.next_is("foo"))
...
lexer.retreat();
lexer.consume_escaped_character(); // This expects lexer.peek() == '\\'
Problem:
- `constexpr_sum` is implemented using `Array` which means the
function needs to be a function template so that the size can be
deduced.
Solution:
- Change the `Array` function argument to a `Span` since `Span` now is
`constexpr`.
Problem:
- Hash functions can be `constexpr`, but are not.
Solution:
- Change `inline` keyword to `constexpr`.
- Add `static_assert` tests to ensure the hash functions work in a
`constexpr` context.
Problem:
- The hash functions have no associated tests, so there is nothing
binding their behavior.
Solution:
- Bind the hash function behavior by adding tests.
- Use the existing behavior as "correct".
Problem:
- `constexpr` functions are decorated with the `inline` specifier
keyword. This is redundant because `constexpr` functions are
implicitly `inline`.
- [dcl.constexpr], §7.1.5/2 in the C++11 standard): "constexpr
functions and constexpr constructors are implicitly inline (7.1.2)".
Solution:
- Remove the redundant `inline` keyword.
Problem:
- `Checked` is not `constexpr`-aware.
Solution:
- Decorate member functions with `constexpr` keyword.
- Add tests to ensure the functionality where possible.
Problem:
- Compiler-generated functions are being defined which results in
extra code to maintain.
Solution:
- Switch to compiler-generated default functions for default
construction, copy assignment, move assignment, copy construction
and move construction.
Problem:
- There is no test which guarantees the CircularQueue does not
construct any objects of the value type. The goal is to have
uninitialized memory which can be used.
Solution:
- Add a test requiring that the constructor of the value type is never
called.
This commit also removes a few functions like raw_out and vwarn. If we
want to write raw output, we can do this as follows:
out("{}", "Hello, World!");
The vout stuff isn't really public API anyways, so no need for another
vwarn.
Problem:
- It is not possible to perform a binary search at compile-time
because `binary_search` is not `constexpr`-aware.
Solution:
- Add `constexpr` support.
This implements the transmit time suggestion in (abandoned?)
draft-ietf-ntp-data-minimization. (The other suggestions were already
implemented as far as I can tell.)
Problem:
- `Span` is not `constexpr` aware.
Solution:
- Add `constexpr` support for all parts that do not require
`reinterpret_cast`.
- Modify tests which use the `constexpr` functions.
Double the capacity when used+deleted buckets crosses 60% of capacity.
This appears to be a sweet spot for performance based on some ad-hoc
testing with test-js. :^)
Instead of each hash bucket being a SinglyLinkedList, switch to using
closed hashing (open addressing). Buckets are chained together via
double hashing (hashing the hash until we find an unused bucket.)
This greatly reduces malloc traffic, since each added element no longer
allocates a new linked list node.
Appears performance neutral on test-js. Can definitely be tuned and
could use proper management of load factor, etc.
There is no portable way to forward declare abort because the libc
implementations disagree on the signature.
Originally, I added a __portable_abort function with a "portable"
signature which just called abort. But I really don't like it and just
including <stdlib.h> is simpler.
Note that the headers we include in <AK/TestSuite.h> are no longer
commutative now, we have to include <stdlib.h> before anything else.
Problem:
- Output of decode and encode grow as the decode and encode
happen. This is inefficient because a large size will require many
reallocations.
- `const` qualifiers are missing on variables which are not intended
to change.
Solution:
- Since the size of the decoded or encoded message is known prior to
starting, calculate the size and set the output to that size
immediately. All appends will not incur the reallocation overhead.
- Add `const` qualifiers to show intent.
* AK: Add formatter for JsonValue.
* Inspector: Use new format functions.
* Profiler: Use new format functions.
* UserspaceEmulator: Use new format functions.
Problem:
- The Base64 alphabet and lookup table are initialized at
run-time. This results in an initial start-up cost as well as a
boolean evaluation and branch every time the function is called.
Solution:
- Provide `constexpr` functions which initialize the alphabet and
lookup table at compile-time. These can be called and assigned to a
`constexpr` variable so that there is no run-time cost associated
with the initialization or lookup.
We are adding the process name as prefix and a newline as suffix to any
message written to debug. Thus, the following doesn't make any sense:
for (u8 byte : bytes)
dbg("{:02x} ", byte);
dbgln();
Which function call would put the prefix? This doesn't make any sense,
thus these functions must go.
The example above could be converted to:
StringBuilder builder;
for (u8 byte : bytes)
builder.appendff("{:02x} ", byte);
dbgln("{}", builder.build());
Problem:
- Constructors and conversion operators are not `constexpr`,
but they can be.
- `constexpr` is needed here so that other classes can add `constexpr`
evaluation.
Solution:
- Add the `constexpr` keyword to the constructors and
conversion operators.
- Add `static_assert` tests which ensure the capability works.
Problem:
- m_data is being passed to the constructor of the parent class before
it is initialized. This is not really a problem because the compiler
knows the location and it is only a span being constructed, but it
triggers a warning in clang for use-before-init.
Solution:
- Initialize using a default constructed array and then overwrite it
inside the constructor after the member is initialized.
Formatter is specialized in the header file. The definition in the
implementation file is extraneous and has no effect. Simply removing
it so that there is no confusion.
String literals are just pointers to a constant character. It should be
possible to format them as such. (The default is to print them as
strings still.)
When we write the format specifier '{:#08x}' we are asking for eight
significant digits, zero padding and the prefix '0x'.
However, previously we got only six significant digits because the
prefix counted towards the width. (The number '8' here is the total
width and not the number of significant digits.)
Both fmtlib and printf shared this behaviour. However, I am introducing
a special case here because when we do zero padding we really only care
about the digits and not the width.
Notice that zero padding is a special case anyways, because zero padding
goes after the prefix as opposed to any other padding which goes before
it.
This would previously fail at runtime, and it would have zero indication
of what exactly went wrong.
Also adds `AK::DependentFalse<Ts...>', which is a...dependent false.
In the future all (normal) output should be written by any of the
following functions:
out (currently called new_out)
outln
dbg (currently called new_dbg)
dbgln
warn (currently called new_warn)
warnln
However, there are still a ton of uses of the old out/warn/dbg in the
code base so the new functions are called new_out/new_warn/new_dbg. I am
going to rename them as soon as all the other usages are gone (this
might take a while.)
I also added raw_out/raw_dbg/raw_warn which don't do any escaping,
this should be useful if no formatting is required and if the input
contains tons of curly braces. (I am not entirely sure if this function
will stay, but I am adding it for now.)
If we're sharing buffers, we only want to share trivial structures
as anything else could potentially share internal pointers, which
most likely is going to cause problems due to different address
spaces.
Fix the GUI::SystemTheme structure, which was not trivial, which
is now caught at compile time.
Fixes#3650
The problem with our test suite is that it can't detect if a test
failed. When a test fails we simply write 'FAIL ...' to stderr and move
on.
Previously, the test suite would list all tests as passing regardless
how many assertions failed. In the future it might be smart to implement
this properly but test suites for C++ are always hard to do nicely.
(Because C++ execution isn't meant to be embedded.)
It's now save to pass a signed integer as parameter and then use it as
replacement field (previously, this would just cast it to size_t which
would be bad.)
This finally takes care of the kind-of excessive boilerplate code that were the
ctype adapters. On the other hand, I had to link `LibC/ctype.cpp` to the Kernel
(for `AK/JsonParser.cpp` and `AK/Format.cpp`). The previous commit actually makes
sense now: the `string.h` includes in `ctype.{h,cpp}` would require to link more LibC
stuff to the Kernel when it only needs the `_ctype_` array of `ctype.cpp`, and there
wasn't any string stuff used in ctype.
Instead of all this I could have put static derivatives of `is_any_of()` in the
concerned AK files, however that would have meant more boilerplate and workarounds;
so I went for the Kernel approach.
