| use std::env; |
| use std::process::Command; |
| use std::str::{self, FromStr}; |
| |
| // The rustc-cfg strings below are *not* public API. Please let us know by |
| // opening a GitHub issue if your build environment requires some way to enable |
| // these cfgs other than by executing our build script. |
| fn main() { |
| let minor = match rustc_minor_version() { |
| Some(minor) => minor, |
| None => return, |
| }; |
| |
| let target = env::var("TARGET").unwrap(); |
| let emscripten = target == "asmjs-unknown-emscripten" || target == "wasm32-unknown-emscripten"; |
| |
| // std::collections::Bound was stabilized in Rust 1.17 |
| // but it was moved to core::ops later in Rust 1.26: |
| // https://doc.rust-lang.org/core/ops/enum.Bound.html |
| if minor >= 26 { |
| println!("cargo:rustc-cfg=ops_bound"); |
| } else if minor >= 17 && cfg!(feature = "std") { |
| println!("cargo:rustc-cfg=collections_bound"); |
| } |
| |
| // CString::into_boxed_c_str stabilized in Rust 1.20: |
| // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str |
| if minor >= 20 { |
| println!("cargo:rustc-cfg=de_boxed_c_str"); |
| } |
| |
| // From<Box<T>> for Rc<T> / Arc<T> stabilized in Rust 1.21: |
| // https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From<Box<T>> |
| // https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From<Box<T>> |
| if minor >= 21 { |
| println!("cargo:rustc-cfg=de_rc_dst"); |
| } |
| |
| // Duration available in core since Rust 1.25: |
| // https://blog.rust-lang.org/2018/03/29/Rust-1.25.html#library-stabilizations |
| if minor >= 25 { |
| println!("cargo:rustc-cfg=core_duration"); |
| } |
| |
| // 128-bit integers stabilized in Rust 1.26: |
| // https://blog.rust-lang.org/2018/05/10/Rust-1.26.html |
| // |
| // Disabled on Emscripten targets as Emscripten doesn't |
| // currently support integers larger than 64 bits. |
| if minor >= 26 && !emscripten { |
| println!("cargo:rustc-cfg=integer128"); |
| } |
| |
| // Inclusive ranges methods stabilized in Rust 1.27: |
| // https://github.com/rust-lang/rust/pull/50758 |
| if minor >= 27 { |
| println!("cargo:rustc-cfg=range_inclusive"); |
| } |
| |
| // Non-zero integers stabilized in Rust 1.28: |
| // https://github.com/rust-lang/rust/pull/50808 |
| if minor >= 28 { |
| println!("cargo:rustc-cfg=num_nonzero"); |
| } |
| } |
| |
| fn rustc_minor_version() -> Option<u32> { |
| let rustc = match env::var_os("RUSTC") { |
| Some(rustc) => rustc, |
| None => return None, |
| }; |
| |
| let output = match Command::new(rustc).arg("--version").output() { |
| Ok(output) => output, |
| Err(_) => return None, |
| }; |
| |
| let version = match str::from_utf8(&output.stdout) { |
| Ok(version) => version, |
| Err(_) => return None, |
| }; |
| |
| let mut pieces = version.split('.'); |
| if pieces.next() != Some("rustc 1") { |
| return None; |
| } |
| |
| let next = match pieces.next() { |
| Some(next) => next, |
| None => return None, |
| }; |
| |
| u32::from_str(next).ok() |
| } |