From 99c0520aa79401b69fb51d38172cd58c6a256cfb Mon Sep 17 00:00:00 2001 From: "pinkforest(she/her)" <36498018+pinkforest@users.noreply.github.com> Date: Sat, 18 Mar 2023 19:34:47 +1100 Subject: [PATCH] Fixes cfg with target from env (#516) * Fixes cfg with target from env * Derive cleanup * Default to curve25519_dalek_bits="32" on unknown target * Give out warning (thanks @jcape) Co-authored-by: ryan Co-authored-by: James Cape --- build.rs | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-) diff --git a/build.rs b/build.rs index a4c6b3e65..ca28d72b4 100644 --- a/build.rs +++ b/build.rs @@ -4,21 +4,16 @@ #[allow(non_camel_case_types)] enum DalekBits { - #[cfg_attr(curve25519_dalek_bits = "64", allow(dead_code))] Dalek32, - #[cfg_attr(curve25519_dalek_bits = "32", allow(dead_code))] Dalek64, } fn main() { - #[cfg(curve25519_dalek_bits = "32")] - let curve25519_dalek_bits = DalekBits::Dalek32; - - #[cfg(curve25519_dalek_bits = "64")] - let curve25519_dalek_bits = DalekBits::Dalek64; - - #[cfg(all(not(curve25519_dalek_bits = "64"), not(curve25519_dalek_bits = "32")))] - let curve25519_dalek_bits = deterministic::determine_curve25519_dalek_bits(); + let curve25519_dalek_bits = match std::env::var("CARGO_CFG_CURVE25519_DALEK_BITS").as_deref() { + Ok("32") => DalekBits::Dalek32, + Ok("64") => DalekBits::Dalek64, + _ => deterministic::determine_curve25519_dalek_bits(), + }; match curve25519_dalek_bits { DalekBits::Dalek64 => println!("cargo:rustc-cfg=curve25519_dalek_bits=\"64\""), @@ -27,22 +22,19 @@ fn main() { } // Deterministic cfg(curve25519_dalek_bits) when this is not explicitly set. -#[cfg(all(not(curve25519_dalek_bits = "64"), not(curve25519_dalek_bits = "32")))] mod deterministic { use super::*; // Standard Cargo TARGET environment variable of triplet is required - static ERR_MSG_NO_TARGET: &str = "Standard Cargo TARGET environment variable is not set."; + static ERR_MSG_NO_TARGET: &str = "Standard Cargo TARGET environment variable is not set"; // Custom Non-Rust standard target platforms require explicit settings. static ERR_MSG_NO_PLATFORM: &str = "Unknown Rust target platform."; - // Error handling when the bits setting cannot be determined - fn determine_curve25519_dalek_bits_error(cause: &str) -> ! { - eprintln!("Error: {cause}"); - eprintln!("Please set cfg(curve25519_dalek_bits) explicitly either as 32 or 64."); - std::process::exit(1) + // Warning when the curve25519_dalek_bits cannot be determined + fn determine_curve25519_dalek_bits_warning(cause: &str) { + println!("cargo:warning=\"Defaulting to curve25519_dalek_bits=32: {cause}\""); } // Determine the curve25519_dalek_bits based on Rust standard TARGET triplet @@ -53,13 +45,19 @@ mod deterministic { // https://doc.rust-lang.org/cargo/reference/environment-variables.html let target_triplet = match std::env::var("TARGET") { Ok(t) => t, - Err(_) => determine_curve25519_dalek_bits_error(ERR_MSG_NO_TARGET), + Err(_) => { + determine_curve25519_dalek_bits_warning(ERR_MSG_NO_TARGET); + return DalekBits::Dalek32; + } }; // platforms crate is the source of truth used to determine the platform let platform = match platforms::Platform::find(&target_triplet) { Some(p) => p, - None => determine_curve25519_dalek_bits_error(ERR_MSG_NO_PLATFORM), + None => { + determine_curve25519_dalek_bits_warning(ERR_MSG_NO_PLATFORM); + return DalekBits::Dalek32; + } }; #[allow(clippy::match_single_binding)]