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|
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() {
println!("cargo:rerun-if-changed=build.rs");
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=no_ops_bound");
if minor < 17 {
println!("cargo:rustc-cfg=no_collections_bound");
}
}
// core::cmp::Reverse stabilized in Rust 1.19:
// https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html
if minor < 19 {
println!("cargo:rustc-cfg=no_core_reverse");
}
// CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20:
// https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
// https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path
if minor < 20 {
println!("cargo:rustc-cfg=no_de_boxed_c_str");
println!("cargo:rustc-cfg=no_de_boxed_path");
}
// 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=no_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=no_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 before Rust 1.40 since
// Emscripten did not support 128-bit integers until Rust 1.40
// (https://github.com/rust-lang/rust/pull/65251)
if minor < 26 || emscripten && minor < 40 {
println!("cargo:rustc-cfg=no_integer128");
}
// Inclusive ranges methods stabilized in Rust 1.27:
// https://github.com/rust-lang/rust/pull/50758
// Also Iterator::try_for_each:
// https://blog.rust-lang.org/2018/06/21/Rust-1.27.html#library-stabilizations
if minor < 27 {
println!("cargo:rustc-cfg=no_range_inclusive");
println!("cargo:rustc-cfg=no_iterator_try_fold");
}
// Non-zero integers stabilized in Rust 1.28:
// https://blog.rust-lang.org/2018/08/02/Rust-1.28.html#library-stabilizations
if minor < 28 {
println!("cargo:rustc-cfg=no_num_nonzero");
}
// TryFrom, Atomic types, non-zero signed integers, and SystemTime::checked_add
// stabilized in Rust 1.34:
// https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto
// https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations
if minor < 34 {
println!("cargo:rustc-cfg=no_core_try_from");
println!("cargo:rustc-cfg=no_num_nonzero_signed");
println!("cargo:rustc-cfg=no_systemtime_checked_add");
println!("cargo:rustc-cfg=no_relaxed_trait_bounds");
}
// Current minimum supported version of serde_derive crate is Rust 1.56.
if minor < 56 {
println!("cargo:rustc-cfg=no_serde_derive");
}
// Support for #[cfg(target_has_atomic = "...")] stabilized in Rust 1.60.
if minor < 60 {
println!("cargo:rustc-cfg=no_target_has_atomic");
// Allowlist of archs that support std::sync::atomic module. This is
// based on rustc's compiler/rustc_target/src/spec/*.rs.
let has_atomic64 = target.starts_with("x86_64")
|| target.starts_with("i686")
|| target.starts_with("aarch64")
|| target.starts_with("powerpc64")
|| target.starts_with("sparc64")
|| target.starts_with("mips64el")
|| target.starts_with("riscv64");
let has_atomic32 = has_atomic64 || emscripten;
if minor < 34 || !has_atomic64 {
println!("cargo:rustc-cfg=no_std_atomic64");
}
if minor < 34 || !has_atomic32 {
println!("cargo:rustc-cfg=no_std_atomic");
}
}
// Support for core::ffi::CStr and alloc::ffi::CString stabilized in Rust 1.64.
// https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#c-compatible-ffi-types-in-core-and-alloc
if minor < 64 {
println!("cargo:rustc-cfg=no_core_cstr");
}
}
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()
}
|
