Make sure temporal_capi can be built no_std (#281)

Ensures that no sys deps get pulled in

Author: Manishearth

.github/workflows/rust.yml

@@ -125,6 +125,12 @@ jobs:
       - name: Makefile tests
         run: cd temporal_capi/cpp_tests && make
 
+      # There's no guarantee that dependencies are no_std unless you test with a toolchain without `std`
+      - name: Install no_std toolchain
+        run: rustup target add thumbv7m-none-eabi
+      - name: Run no_std tests
+        run: cargo check -p temporal_capi --target thumbv7m-none-eabi
+
   docs:
     name: Documentation
     runs-on: ubuntu-latest

Cargo.lock

@@ -28,7 +28,7 @@ temporal_provider = { version = "~0.0.6", path = "./provider" }
 tinystr = "0.8.1"
 icu_calendar = { version = "2.0.0-beta2", default-features = false }
 rustc-hash = "2.1.0"
-num-traits = "0.2.19"
+num-traits = { version = "0.2.19", default-features = false }
 ixdtf = "0.4.0"
 iana-time-zone = "0.1.63"
 log = "0.4.27"
@@ -71,6 +71,7 @@ combine = { workspace = true, optional = true }
 
 # System time feature
 web-time = { workspace = true, optional =  true }
+core_maths = "0.1.1"
 
 [features]
 default = ["sys"]

Cargo.toml

@@ -1,6 +1,7 @@
 use core::num::{NonZeroU128, NonZeroU32};
 
 use crate::{TemporalError, TemporalResult};
+use num_traits::float::FloatCore;
 
 // ==== RoundingIncrement option ====
 
@@ -31,7 +32,7 @@ impl TryFrom<f64> for RoundingIncrement {
         }
 
         // 5. Let integerIncrement be truncate(ℝ(increment)).
-        let integer_increment = value.trunc();
+        let integer_increment = FloatCore::trunc(value);
         // 6. If integerIncrement < 1 or integerIncrement > 10**9, throw a RangeError exception.
         if !(1.0..=1_000_000_000.0).contains(&integer_increment) {
             return Err(TemporalError::range()

src/options/increment.rs

@@ -1,6 +1,7 @@
 //! Implementation of the FiniteF64 primitive
 
 use crate::{TemporalError, TemporalResult};
+use num_traits::float::FloatCore;
 use num_traits::{AsPrimitive, FromPrimitive, PrimInt};
 
 #[derive(Debug, Default, Clone, Copy, PartialEq, PartialOrd)]
@@ -48,7 +49,7 @@ impl FiniteF64 {
 
     #[inline]
     pub fn checked_mul_add(&self, a: FiniteF64, b: FiniteF64) -> TemporalResult<Self> {
-        let result = Self(self.0.mul_add(a.0, b.0));
+        let result = Self(core_maths::CoreFloat::mul_add(self.0, a.0, b.0));
         if !result.0.is_finite() {
             return Err(TemporalError::range().with_message("number value is not a finite value."));
         }
@@ -77,7 +78,7 @@ impl FiniteF64 {
     where
         f64: AsPrimitive<T>,
     {
-        if self.0 != self.0.trunc() {
+        if self.0 != FloatCore::trunc(self.0) {
             return Err(TemporalError::range().with_message("value must be integral."));
         }
         Ok(self.0.as_())

src/primitive.rs

@@ -11,6 +11,7 @@ use core::{
     ops::{Div, Neg},
 };
 
+use num_traits::float::FloatCore;
 use num_traits::{ConstZero, Euclid, FromPrimitive, NumCast, Signed, ToPrimitive};
 
 pub(crate) trait Roundable:
@@ -98,14 +99,16 @@ impl Roundable for f64 {
 
     fn compare_remainder(dividend: Self, divisor: Self) -> Option<Ordering> {
         let quotient = Roundable::quotient_abs(dividend, divisor);
-        let d1 = quotient - quotient.floor();
-        let d2 = quotient.ceil() - quotient;
+        let d1 = quotient - FloatCore::floor(quotient);
+        let d2 = FloatCore::ceil(quotient) - quotient;
         d1.partial_cmp(&d2)
     }
 
     fn is_even_cardinal(dividend: Self, divisor: Self) -> bool {
         let quotient = Roundable::quotient_abs(dividend, divisor);
-        (quotient.floor() / (quotient.ceil() - quotient.floor()) % 2.0) == 0.0
+        (FloatCore::floor(quotient) / (FloatCore::ceil(quotient) - FloatCore::floor(quotient))
+            % 2.0)
+            == 0.0
     }
 
     fn result_floor(dividend: Self, divisor: Self) -> u128 {

src/rounding.rs

@@ -9,8 +9,9 @@ pub mod ffi {
     use crate::plain_date::ffi::{PartialDate, PlainDate};
     use crate::plain_month_day::ffi::PlainMonthDay;
     use crate::plain_year_month::ffi::PlainYearMonth;
+    use alloc::boxed::Box;
+    use core::fmt::Write;
     use diplomat_runtime::DiplomatStr;
-    use std::fmt::Write;
 
     #[diplomat::enum_convert(icu_calendar::any_calendar::AnyCalendarKind, needs_wildcard)]
     pub enum AnyCalendarKind {

temporal_capi/src/calendar.rs

@@ -5,6 +5,7 @@ use crate::error::ffi::TemporalError;
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
     use crate::error::ffi::TemporalError;
+    use alloc::boxed::Box;
     use diplomat_runtime::DiplomatOption;
     use num_traits::FromPrimitive;
 

temporal_capi/src/duration.rs

@@ -2,7 +2,6 @@
 #[diplomat::abi_rename = "temporal_rs_{0}"]
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
-
     #[diplomat::enum_convert(temporal_rs::error::ErrorKind)]
     pub enum ErrorKind {
         Generic,

temporal_capi/src/error.rs

@@ -5,6 +5,7 @@ pub mod ffi {
     use crate::duration::ffi::{Duration, TimeDuration};
     use crate::error::ffi::TemporalError;
     use crate::options::ffi::{DifferenceSettings, RoundingOptions};
+    use alloc::boxed::Box;
 
     #[diplomat::opaque]
     pub struct Instant(pub temporal_rs::Instant);