Use custom Instant implementation on Linux, macOS and iOS #445
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We can't use std's Instant as it's insufficiently specified. It neither guarantees "real time" nor does it guarantee measuring "uptime" (the time the OS has been awake rather than suspended), meaning that you can't actually rely on it in practice. In livesplit-core we definitely want real time rather than uptime. The problem is mostly Linux. POSIX intends for `CLOCK_MONOTONIC` to be real time, but this wasn't correctly implemented in Linux and due to backwards compatibility concerns they were never able to fix it properly. Thus `CLOCK_MONOTONIC` means uptime on Linux whereas on other Unixes it means real time. They however introduced `CLOCK_BOOTTIME` in the Linux kernel 2.6.39 which measures real time. So the solution is to use this on all operating systems that are based on the Linux kernel and fall back to `CLOCK_MONOTONIC` if the kernel is too old and the syscall fails. macOS and iOS actually do the right thing for `CLOCK_MONOTONIC` but Rust actually doesn't use it on iOS and macOS, so we also need to use our custom implementation for those too, but skip `CLOCK_BOOTTIME` as that is Linux specific. On Windows Instant currently measures real time, but we may need to use a custom implementation for it as well in case this ever changes.
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- Runs now support custom variables that are key value pairs that either the user can specify in the run editor or are provided by a script like an auto splitter. [#201](#201) - There is now an option in the run editor to generate a comparison based on a user specified goal time. This uses the same algorithm as the `Balanced PB` comparison but with the time specified instead of the personal best. [#209](#209) - Images internally are now stored as is without being reencoded as Base64 which was done before in order to make it easier for the web LiveSplit One to display them. [#227](#227) - The Splits.io API is now available under the optional `networking` feature. [#236](#236) - All key value based components share the same component state type now. [#257](#257) - The crate now properly supports `wasm-bindgen` and `WASI`. [#263](#263) - There is now a dedicated component for displaying the comparison's segment time. [#264](#264) - Compiling the crate without `std` is now supported. Most features are not supported at this time though. [#270](#270) - [`Splitterino`](https://github.com/prefixaut/splitterino) splits can now be parsed. [#276](#276) - The `Timer` component can now show a segment timer instead. [#288](#288) - Gamepads are now supported on the web. [#310](#310) - The underlying "skill curve" that the `Balanced PB` samples is now exposed in the API. [#330](#330) - The layout states can now be updated, which means almost all of the allocations can be reused from the previous frame. This is a lot faster. [#334](#334) - In order to calculate a layout state, the timer now provides a snapshot mechanism that ensures that the layout state gets calculated at a fixed point in time. [#339](#339) - Text shaping is now done via `rustybuzz` which is a port of `harfbuzz`. [#378](#378) - Custom fonts are now supported. [#385](#385) - The renderer is not based on meshes anymore that are suitable for rendering with a 3D graphics API. Instead the renderer is now based on paths, which are suitable for rendering with a 2D graphics API such as Direct2D, Skia, HTML Canvas, and many more. The software renderer is now based on `tiny-skia` which is so fast that it actually outperforms any other rendering and is the recommended way to render. [#408](#408) - Remove support for parsing `worstrun` splits. `worstrun` doesn't support splits anymore, so `livesplit-core` doesn't need to keep its parsing support. [#411](#411) - Remove support for parsing `Llanfair 2` splits. `Llanfair 2` was never publicly available and is now deleted entirely. [#420](#420) - Hotkeys are now supported on macOS. [#422](#422) - The renderer is now based on two layers. A bottom layer that rarely needs to be rerendered and the top layer that needs to be rerendered on every frame. Additionally the renderer is now a scene manager which manages a scene that an actual rendering backend can then render out. [#430](#430) - The hotkeys are now based on the [UI Events KeyboardEvent code Values](https://www.w3.org/TR/uievents-code/) web standard. [#440](#440) - Timing is now based on `CLOCK_BOOTTIME` on Linux and `CLOCK_MONOTONIC` on macOS and iOS. This ensures that all platforms keep tracking time while the operating system is in a suspended state. [#445](#445) - Segment time columns are now formatted as segment times. [#448](#448) - Hotkeys can now be resolved to the US keyboard layout. [#452](#452) - They hotkeys are now based on `keydown` instead of `keypress` in the web. `keydown` handles all keys whereas `keypress` only handles visual keys and is also deprecated. [#455](#455) - Hotkeys can now be resolved to the user's keyboard layout on both Windows and macOS. [#459](#459) and [#460](#460) - The `time` crate is now used instead of `chrono` for keeping track of time. [#462](#462) - The scene manager now caches a lot more information. This improves the performance a lot as it does not need to reshape the text on every frame anymore, which is a very expensive operation. [#466](#466) and [#467](#467) - The hotkeys on Linux are now based on `evdev`, which means Wayland is now supported. Additionally the hotkeys are not consuming the key press anymore. [#474](#474) - When holding down a key, the hotkey doesn't repeat anymore on Linux, macOS and WebAssembly. The problem still occurs on Windows at this time. [#475](#475) and [#476](#476)
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We can't use std's Instant as it's insufficiently specified. It neither guarantees "real time" nor does it guarantee measuring "uptime" (the time the OS has been awake rather than suspended), meaning that you can't actually rely on it in practice. In livesplit-core we definitely want real time rather than uptime. The problem is mostly Linux. POSIX intends for
CLOCK_MONOTONICto be real time, but this wasn't correctly implemented in Linux and due to backwards compatibility concerns they were never able to fix it properly. ThusCLOCK_MONOTONICmeans uptime on Linux whereas on other Unixes it means real time. They however introducedCLOCK_BOOTTIMEin the Linux kernel 2.6.39 which measures real time. So the solution is to use this on all operating systems that are based on the Linux kernel and fall back toCLOCK_MONOTONICif the kernel is too old and the syscall fails.macOS and iOS actually do the right thing for
CLOCK_MONOTONICbut Rust actually doesn't use it on iOS and macOS, so we also need to use our custom implementation for those too, but skipCLOCK_BOOTTIMEas that is Linux specific.On Windows Instant currently measures real time, but we may need to use a custom implementation for it as well in case this ever changes.
Resolves #442