| use std::env; |
| use std::ffi::OsString; |
| use std::process::Command; |
| |
| fn main() { |
| let rustc = env::var_os("RUSTC").unwrap_or(OsString::from("rustc")); |
| let output = Command::new(&rustc) |
| .arg("--version") |
| .output() |
| .expect("failed to check 'rustc --version'") |
| .stdout; |
| |
| let version = String::from_utf8(output) |
| .expect("rustc version output should be utf-8"); |
| |
| enable_new_features(&version); |
| } |
| |
| fn enable_new_features(raw_version: &str) { |
| let version = match Version::parse(raw_version) { |
| Ok(version) => version, |
| Err(err) => { |
| println!("cargo:warning=failed to parse `rustc --version`: {}", err); |
| return; |
| } |
| }; |
| |
| enable_simd(version); |
| } |
| |
| fn enable_simd(version: Version) { |
| if env::var_os("CARGO_FEATURE_STD").is_none() { |
| println!("cargo:warning=building for no_std disables httparse SIMD"); |
| return; |
| } |
| |
| let env_disable = "CARGO_CFG_HTTPARSE_DISABLE_SIMD"; |
| if env::var_os(env_disable).is_some() { |
| println!("cargo:warning=detected {} environment variable, disabling SIMD", env_disable); |
| return; |
| } |
| |
| let min_simd_version = Version { |
| major: 1, |
| minor: 27, |
| patch: 0, |
| }; |
| |
| if version >= min_simd_version { |
| println!("cargo:rustc-cfg=httparse_simd"); |
| } |
| |
| // cfg(target_feature) isn't stable yet, but CARGO_CFG_TARGET_FEATURE has |
| // a list... We aren't doing anything unsafe, since the is_x86_feature_detected |
| // macro still checks in the actual lib, BUT! |
| // |
| // By peeking at the list here, we can change up slightly how we do feature |
| // detection in the lib. If our features aren't in the feature list, we |
| // stick with a cached runtime detection strategy. |
| // |
| // But if the features *are* in the list, we benefit from removing our cache, |
| // since the compiler will eliminate several branches with its internal |
| // cfg(target_feature) usage. |
| |
| |
| let env_runtime_only = "CARGO_CFG_HTTPARSE_DISABLE_SIMD_COMPILETIME"; |
| if env::var_os(env_runtime_only).is_some() { |
| println!("cargo:warning=detected {} environment variable, using runtime SIMD detection only", env_runtime_only); |
| return; |
| } |
| let feature_list = match env::var_os("CARGO_CFG_TARGET_FEATURE") { |
| Some(var) => match var.into_string() { |
| Ok(s) => s, |
| Err(_) => { |
| println!("cargo:warning=CARGO_CFG_TARGET_FEATURE was not valid utf-8"); |
| return; |
| }, |
| }, |
| None => { |
| println!("cargo:warning=CARGO_CFG_TARGET_FEATURE was not set"); |
| return |
| }, |
| }; |
| |
| let mut saw_sse42 = false; |
| let mut saw_avx2 = false; |
| |
| for feature in feature_list.split(',') { |
| let feature = feature.trim(); |
| if !saw_sse42 && feature == "sse4.2" { |
| saw_sse42 = true; |
| println!("cargo:rustc-cfg=httparse_simd_target_feature_sse42"); |
| } |
| |
| if !saw_avx2 && feature == "avx2" { |
| saw_avx2 = true; |
| println!("cargo:rustc-cfg=httparse_simd_target_feature_avx2"); |
| } |
| } |
| } |
| |
| #[derive(Debug, Clone, Copy, PartialEq, PartialOrd)] |
| struct Version { |
| major: u32, |
| minor: u32, |
| patch: u32, |
| } |
| |
| impl Version { |
| fn parse(mut s: &str) -> Result<Version, String> { |
| if !s.starts_with("rustc ") { |
| return Err(format!("unrecognized version string: {}", s)); |
| } |
| s = &s["rustc ".len()..]; |
| |
| let parts: Vec<&str> = s.split(".").collect(); |
| if parts.len() < 3 { |
| return Err(format!("not enough version parts: {:?}", parts)); |
| } |
| |
| let mut num = String::new(); |
| for c in parts[0].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let major = try!(num.parse::<u32>().map_err(|e| e.to_string())); |
| |
| num.clear(); |
| for c in parts[1].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let minor = try!(num.parse::<u32>().map_err(|e| e.to_string())); |
| |
| num.clear(); |
| for c in parts[2].chars() { |
| if !c.is_digit(10) { |
| break; |
| } |
| num.push(c); |
| } |
| let patch = try!(num.parse::<u32>().map_err(|e| e.to_string())); |
| |
| Ok(Version { |
| major: major, |
| minor: minor, |
| patch: patch, |
| }) |
| } |
| } |
| |