替代方案

• cargo-platform
• parse_cfg

用法

cfg-expr 是一个 crate，可以用来解析和评估 Rust cfg() 表达式，包括作为 Rust 代码本身中的声明，以及在 cargo 清单的 [target.'cfg()'.dependencies] 部分。

它包含了一个已知于 rustc 的所有内置目标列表（截至 1.80.0），可用于确定特定的 cfg 表达式是否可满足。

use cfg_expr::{targets::get_builtin_target_by_triple, Expression, Predicate};

let specific = Expression::parse(
    r#"all(
        target_os = "windows",
        target_arch = "x86",
        windows,
        target_env = "msvc",
        target_feature = "fxsr",
        target_feature = "sse",
        target_feature = "sse2",
        target_pointer_width = "32",
        target_endian = "little",
        not(target_vendor = "uwp"),
        feature = "cool_thing",
    )"#,
).unwrap();

// cfg_expr includes a list of every builtin target in rustc
let x86_win = get_builtin_target_by_triple("i686-pc-windows-msvc").unwrap();
let x86_pentium_win = get_builtin_target_by_triple("i586-pc-windows-msvc").unwrap();
let uwp_win = get_builtin_target_by_triple("i686-uwp-windows-msvc").unwrap();
let mac = get_builtin_target_by_triple("x86_64-apple-darwin").unwrap();

let avail_target_feats = ["fxsr", "sse", "sse2"];

// This will satisfy all requirements
assert!(specific.eval(|pred| {
    match pred {
        Predicate::Target(tp) => tp.matches(x86_win),
        Predicate::TargetFeature(feat) => avail_target_feats.contains(feat),
        Predicate::Feature(feat) => *feat == "cool_thing",
        _ => false,
    }
}));

// This won't, it doesn't have the cool_thing feature!
assert!(!specific.eval(|pred| {
    match pred {
        Predicate::Target(tp) => tp.matches(x86_pentium_win),
        Predicate::TargetFeature(feat) => avail_target_feats.contains(feat),
        _ => false,
    }
}));

// This will *not* satisfy the vendor predicate
assert!(!specific.eval(|pred| {
    match pred {
        Predicate::Target(tp) => tp.matches(uwp_win),
        Predicate::TargetFeature(feat) => avail_target_feats.contains(feat),
        _ => false,
    }
}));

// This will *not* satisfy the vendor, os, or env predicates
assert!(!specific.eval(|pred| {
    match pred {
        Predicate::Target(tp) => tp.matches(mac),
        Predicate::TargetFeature(feat) => avail_target_feats.contains(feat),
        _ => false,
    }
}));

贡献

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许可证

根据以下之一获得许可

• Apache 许可证第 2 版 (LICENSE-APACHE 或 https://apache.ac.cn/licenses/LICENSE-2.0)
• MIT 许可证 (LICENSE-MIT 或 http://opensource.org/licenses/MIT)

由您选择。

贡献

除非您明确声明，否则根据 Apache-2.0 许可证定义的，任何有意提交以包含在作品中的贡献，均应如上所述双许可，不附加任何额外条款或条件。