Intern known targets

Author: Nemo157

Cargo.lock

@@ -46,6 +46,7 @@ base64 = "0.12.1"
 strum = { version = "0.18.0", features = ["derive"] }
 lol_html = "0.2"
 dashmap = "3.11.10"
+string_cache = "0.8.0"
 
 # Async
 tokio = { version = "0.2.22", features = ["rt-threaded"] }
@@ -93,6 +94,7 @@ rand = "0.7.3"
 time = "0.1"
 git2 = { version = "0.13", default-features = false }
 sass-rs = "0.2.2"
+string_cache_codegen = "0.5.1"
 
 [[bench]]
 name = "html_parsing"

Cargo.toml

@@ -28,6 +28,7 @@ fn main() {
         panic!("Error compiling sass: {}", sass_err);
     }
     copy_js();
+    write_known_targets().unwrap();
 }
 
 fn write_git_version() {
@@ -108,3 +109,21 @@ fn copy_js() {
         fs::copy(&source_path, &dest_path).expect("Copy JavaScript file to target");
     });
 }
+
+fn write_known_targets() -> std::io::Result<()> {
+    use std::io::BufRead;
+
+    let targets: Vec<String> = std::process::Command::new("rustc")
+        .args(&["--print", "target-list"])
+        .output()?
+        .stdout
+        .lines()
+        .filter(|s| s.as_ref().map_or(true, |s| !s.is_empty()))
+        .collect::<std::io::Result<_>>()?;
+
+    string_cache_codegen::AtomType::new("target::TargetAtom", "target_atom!")
+        .atoms(&targets)
+        .write_to_file(&Path::new(&env::var("OUT_DIR").unwrap()).join("target_atom.rs"))?;
+
+    Ok(())
+}

build.rs

@@ -26,6 +26,13 @@ mod test;
 pub mod utils;
 mod web;
 
+#[allow(dead_code)]
+mod target {
+    //! [`crate::target::TargetAtom`] is an interned string type for rustc targets, such as
+    //! `x86_64-unknown-linux-gnu`. See the [`string_cache`] docs for usage examples.
+    include!(concat!(env!("OUT_DIR"), "/target_atom.rs"));
+}
+
 use web::page::GlobalAlert;
 
 // Warning message shown in the navigation bar of every page. Set to `None` to hide it.

src/lib.rs

@@ -3,6 +3,7 @@ mod macros;
 
 use self::macros::MetricFromOpts;
 use crate::db::Pool;
+use crate::target::TargetAtom;
 use crate::BuildQueue;
 use dashmap::DashMap;
 use failure::Error;
@@ -81,7 +82,7 @@ metrics! {
 pub(crate) struct RecentlyAccessedReleases {
     krates: DashMap<i32, Instant>,
     versions: DashMap<i32, Instant>,
-    platforms: DashMap<(i32, String), Instant>,
+    platforms: DashMap<(i32, TargetAtom), Instant>,
 }
 
 impl RecentlyAccessedReleases {
@@ -93,7 +94,7 @@ impl RecentlyAccessedReleases {
         self.krates.insert(krate, Instant::now());
         self.versions.insert(version, Instant::now());
         self.platforms
-            .insert((version, target.to_owned()), Instant::now());
+            .insert((version, TargetAtom::from(target)), Instant::now());
     }
 
     pub(crate) fn gather(&self, metrics: &Metrics) {