Monotonic uses QueryPerformanceCounter, while realtime uses
GetSystemTimeAsFileTime. These should approximate clock_gettime
fairly accurately. The QPC implementation only grabs microseconds,
but if we have actual use cases for nanos, we can bump that up.
Co-authored-by: Andrew Kaster <akaster@serenityos.org>
This class takes on the duties of CLOCK_MONOTONIC, a time without a
defined reference point that always increases. This informs some
important design decisions about the class API: MonotonicTime cannot be
constructed from external time data, except as a computation based on
other monotonic time, or the current monotonic time. Importantly, there
is no default constructor, since the reference point of monotonic time
is unspecified and therefore without meaning as a default.
The current use of monotonic time (via Duration) includes some potential
problems that may be caught when we move most to all code to
MonotonicTime in the next commit.
The API restrictions have one important relaxation:
Kernel::TimeManagement is allowed to exchange raw time data within
MonotonicTime freely. This is required for the clock-agnostic time
accessors for timeouts and syscalls, as well as creating monotonic time
data from hardware in the first place.
This is a generic wrapper for a time instant relative to the unix epoch,
and does not account for leap seconds. It should be used in place of
Duration in most current cases.
This is a trivial change, and since this batch of commits will make a
large-scale rebuild necessary anyways, it seems sensible. The feature is
useful for e.g. building compound constant durations at compile time in
a readable way.
That's what this class really is; in fact that's what the first line of
the comment says it is.
This commit does not rename the main files, since those will contain
other time-related classes in a little bit.
A lot of places were relying on AK/Traits.h to give it strnlen, memcmp,
memcpy and other related declarations.
In the quest to remove inclusion of LibC headers from Kernel files, deal
with all the fallout of this included-everywhere header including less
things.
This allows us to make all comparision operators on the class constexpr
without pulling in a bunch of boilerplate. We don't use the `<compare>`
header because it doesn't compile in the main serenity cross-build due
to the include paths to LibC being incompatible with how libc++ expects
them to be for clang builds.
This patch adds the `USING_AK_GLOBALLY` macro which is enabled by
default, but can be overridden by build flags.
This is a step towards integrating Jakt and AK types.
C++20 can automatically synthesize `operator!=` from `operator==`, so
there is no point in writing such functions by hand if all they do is
call through to `operator==`.
This fixes a compile error with compilers that implement P2468 (Clang
16 currently). This paper restores the C++17 behavior that if both
`T::operator==(U)` and `T::operator!=(U)` exist, `U == T` won't be
rewritten in reverse to call `T::operator==(U)`. Removing `!=` operators
makes the rewriting possible again.
See https://reviews.llvm.org/D134529#3853062
This is the initial port of Lagom to win32. This will enable developers
to use Lagom as an alternative to vanilla STL/StandardC++Library - which
gives a much richer environment (think QtCore - but modern).
My main incentive - is to have a native Windows Ladybird working.
I am starting with AK, which does not yet fully compile (on mingw). When
AK is compiling (currently fails building StringBuffer.cpp) - I will
continue to LibCore and then the rest of the user space libraries
(excluding the GUI, which will be another different effort).
Most of the code is happily stollen from Andrew Kaster's fork - he
deserves the credit.
Co-authored-by: Andrew Kaster <akaster@serenityos.org>
In order for this method to be used within LibC itself, avoid using the
floor() method from LibM, which is not available from within LibC. This
header similarly avoids other standard headers as well.
This is just to allow removing the 'clang-format off' directive. This
concept is only used within this header, so it doesn't need to be in the
global namespace.
In the quest of removing as timespec / timeval usage in the Userland as
possible, we need a way to conveniently retrieving the current clock
time from the kernel and storing it in `AK::Time` format.
The previous implementation was too generic, and would cause conflicting
operator overload errors when included in certain code paths. Fix this
by restricting the template parameters to types which have the same
member names as `struct timespec`.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
By making the Time constructor constexpr we can optimize creating a
Time instance from hardcoded values.
Also add more functions to convert between Time and various time units.
