1 files changed, 165 insertions, 0 deletions
diff --git a/third_party/rust/httparse/build.rs b/third_party/rust/httparse/build.rs
new file mode 100644
index 0000000000..3831590609
--- /dev/null
+++ b/third_party/rust/httparse/build.rs
@@ -0,0 +1,165 @@
+use std::env;
+//use std::ffi::OsString;
+//use std::process::Command;
+
+fn main() {
+    // We don't currently need to check the Version anymore...
+    // But leaving this in place in case we need to in the future.
+    /*
+    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;
+    }
+    if env::var_os("CARGO_CFG_MIRI").is_some() {
+        println!("cargo:warning=building for Miri disables httparse SIMD");
+        return;
+    }
+
+    let env_disable = "CARGO_CFG_HTTPARSE_DISABLE_SIMD";
+    if var_is(env_disable, "1") {
+        println!("cargo:warning=detected {} environment variable, disabling SIMD", env_disable);
+        return;
+    }
+
+    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 var_is(env_runtime_only, "1") {
+        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 = 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 = 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 = num.parse::<u32>().map_err(|e| e.to_string())?;
+
+        Ok(Version {
+            major: major,
+            minor: minor,
+            patch: patch,
+        })
+    }
+}
+*/
+
+fn var_is(key: &str, val: &str) -> bool {
+    match env::var(key) {
+        Ok(v) => v == val,
+        Err(_) => false,
+    }
+}