Add a DownloadSource enum

This simplifies the arguments to `download_component` in config.rs.

It also moves stage0.json metadata handling to `Build::new`, making it easier to download the stage0
compiler in rustbuild later if necessary.

src/bootstrap/config.rs

@@ -20,6 +20,7 @@ use crate::channel::GitInfo;
 pub use crate::flags::Subcommand;
 use crate::flags::{Color, Flags};
 use crate::util::{exe, output, program_out_of_date, t};
+use crate::RustfmtMetadata;
 use once_cell::sync::OnceCell;
 use serde::{Deserialize, Deserializer};
 
@@ -1483,25 +1484,8 @@ fn download_ci_rustc_commit(download_rustc: Option<StringOrBool>, verbose: bool)
 }
 
 fn maybe_download_rustfmt(builder: &Builder<'_>) -> Option<PathBuf> {
- #[derive(Deserialize)]
- struct Stage0Metadata {
- dist_server: String,
- checksums_sha256: HashMap<String, String>,
- rustfmt: Option<RustfmtMetadata>,
- }
- #[derive(Deserialize)]
- struct RustfmtMetadata {
- date: String,
- version: String,
- }
-
- let stage0_json = builder.read(&builder.src.join("src").join("stage0.json"));
- let Stage0Metadata { dist_server, checksums_sha256, rustfmt } =
- t!(serde_json::from_str::<Stage0Metadata>(&stage0_json));
- let RustfmtMetadata { date, version } = rustfmt?;
+ let RustfmtMetadata { date, version } = builder.stage0_metadata.rustfmt.as_ref()?;
  let channel = format!("{version}-{date}");
- let mut dist_server = env::var("RUSTUP_DIST_SERVER").unwrap_or(dist_server);
- dist_server.push_str("/dist");
 
  let host = builder.config.build;
  let rustfmt_path = builder.config.initial_rustc.with_file_name(exe("rustfmt", host));
@@ -1512,15 +1496,7 @@ fn maybe_download_rustfmt(builder: &Builder<'_>) -> Option<PathBuf> {
  }
 
  let filename = format!("rustfmt-{version}-{build}.tar.xz", build = host.triple);
- download_component(
- builder,
- &dist_server,
- filename,
- "rustfmt-preview",
- &date,
- "stage0",
- Some(checksums_sha256),
- );
+ download_component(builder, DownloadSource::Dist, filename, "rustfmt-preview", &date, "stage0");
 
  builder.fix_bin_or_dylib(&bin_root.join("bin").join("rustfmt"));
  builder.fix_bin_or_dylib(&bin_root.join("bin").join("cargo-fmt"));
@@ -1563,28 +1539,24 @@ fn download_ci_rustc(builder: &Builder<'_>, commit: &str) {
  }
 }
 
+pub(crate) enum DownloadSource {
+ CI,
+ Dist,
+}
+
 /// Download a single component of a CI-built toolchain (not necessarily a published nightly).
 // NOTE: intentionally takes an owned string to avoid downloading multiple times by accident
 fn download_ci_component(builder: &Builder<'_>, filename: String, prefix: &str, commit: &str) {
- download_component(
- builder,
- "https://ci-artifacts.rust-lang.org/rustc-builds",
- filename,
- prefix,
- commit,
- "ci-rustc",
- None,
- )
+ download_component(builder, DownloadSource::CI, filename, prefix, commit, "ci-rustc")
 }
 
 fn download_component(
  builder: &Builder<'_>,
- base_url: &str,
+ mode: DownloadSource,
  filename: String,
  prefix: &str,
  key: &str,
  destination: &str,
- checksums: Option<HashMap<String, String>>,
 ) {
  let cache_dst = builder.out.join("cache");
  let cache_dir = cache_dst.join(key);
@@ -1594,20 +1566,31 @@ fn download_component(
 
  let bin_root = builder.out.join(builder.config.build.triple).join(destination);
  let tarball = cache_dir.join(&filename);
- let url = format!("{key}/{filename}");
+ let (base_url, url, should_verify) = match mode {
+ DownloadSource::CI => (
+ "https://ci-artifacts.rust-lang.org/rustc-builds".to_string(),
+ format!("{key}/{filename}"),
+ false,
+ ),
+ DownloadSource::Dist => {
+ let dist_server = env::var("RUSTUP_DIST_SERVER")
+ .unwrap_or(builder.stage0_metadata.dist_server.to_string());
+ // NOTE: make `dist` part of the URL because that's how it's stored in src/stage0.json
+ (dist_server, format!("dist/{key}/{filename}"), true)
+ }
+ };
 
  // For the beta compiler, put special effort into ensuring the checksums are valid.
  // FIXME: maybe we should do this for download-rustc as well? but it would be a pain to update
  // this on each and every nightly ...
- let checksum = if let Some(checksums) = &checksums {
+ let checksum = if should_verify {
  let error = format!(
  "src/stage0.json doesn't contain a checksum for {url}. \
  Pre-built artifacts might not be available for this \
  target at this time, see https://doc.rust-lang.org/nightly\
  /rustc/platform-support.html for more information."
  );
- // TODO: add an enum { Commit, Published } so we don't have to hardcode `dist` in two places
- let sha256 = checksums.get(&format!("dist/{url}")).expect(&error);
+ let sha256 = builder.stage0_metadata.checksums_sha256.get(&url).expect(&error);
  if tarball.exists() {
  if builder.verify(&tarball, sha256) {
  builder.unpack(&tarball, &bin_root, prefix);
@@ -1627,7 +1610,7 @@ fn download_component(
  None
  };
 
- builder.download_component(base_url, &url, &tarball, "");
+ builder.download_component(&base_url, &url, &tarball, "");
  if let Some(sha256) = checksum {
  if !builder.verify(&tarball, sha256) {
  panic!("failed to verify {}", tarball.display());

src/bootstrap/lib.rs

@@ -118,6 +118,7 @@ use std::os::windows::fs::symlink_file;
 
 use filetime::FileTime;
 use once_cell::sync::OnceCell;
+use serde::Deserialize;
 
 use crate::builder::Kind;
 use crate::config::{LlvmLibunwind, TargetSelection};
@@ -294,6 +295,7 @@ pub struct Build {
  targets: Vec<TargetSelection>,
 
  // Stage 0 (downloaded) compiler, lld and cargo or their local rust equivalents
+ stage0_metadata: Stage0Metadata,
  initial_rustc: PathBuf,
  initial_cargo: PathBuf,
  initial_lld: PathBuf,
@@ -320,6 +322,18 @@ pub struct Build {
  metrics: metrics::BuildMetrics,
 }
 
+#[derive(Deserialize)]
+struct Stage0Metadata {
+ dist_server: String,
+ checksums_sha256: HashMap<String, String>,
+ rustfmt: Option<RustfmtMetadata>,
+}
+#[derive(Deserialize)]
+struct RustfmtMetadata {
+ date: String,
+ version: String,
+}
+
 #[derive(Debug)]
 struct Crate {
  name: Interned<String>,
@@ -468,7 +482,11 @@ impl Build {
  bootstrap_out
  };
 
+ let stage0_json = t!(std::fs::read_to_string(&src.join("src").join("stage0.json")));
+ let stage0_metadata = t!(serde_json::from_str::<Stage0Metadata>(&stage0_json));
+
  let mut build = Build {
+ stage0_metadata,
  initial_rustc: config.initial_rustc.clone(),
  initial_cargo: config.initial_cargo.clone(),
  initial_lld,