Refactor: Extract new crate binstalk-registry (#1289)

To speedup codegen of `binstalk` and enable it to be reused.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

crates/binstalk-registry/src/git_registry.rs

@@ -0,0 +1,145 @@
+use std::{io, path::PathBuf, sync::Arc};
+
+use binstalk_downloader::{
+    git::{GitCancellationToken, GitUrl, Repository},
+    remote::Client,
+};
+use binstalk_types::cargo_toml_binstall::Meta;
+use cargo_toml_workspace::cargo_toml::Manifest;
+use compact_str::{CompactString, ToCompactString};
+use once_cell::sync::OnceCell;
+use semver::VersionReq;
+use serde_json::{from_slice as json_from_slice, Deserializer as JsonDeserializer};
+use tempfile::TempDir;
+use tokio::task::spawn_blocking;
+use url::Url;
+
+use crate::{
+    crate_prefix_components, parse_manifest, render_dl_template, MatchedVersion, RegistryConfig,
+    RegistryError,
+};
+
+#[derive(Debug)]
+struct GitIndex {
+    _tempdir: TempDir,
+    repo: Repository,
+    dl_template: CompactString,
+}
+
+impl GitIndex {
+    fn new(url: GitUrl, cancellation_token: GitCancellationToken) -> Result<Self, RegistryError> {
+        let tempdir = TempDir::new()?;
+
+        let repo = Repository::shallow_clone_bare(
+            url.clone(),
+            tempdir.as_ref(),
+            Some(cancellation_token),
+        )?;
+
+        let config: RegistryConfig = {
+            let config = repo
+                .get_head_commit_entry_data_by_path("config.json")?
+                .ok_or_else(|| {
+                    io::Error::new(
+                        io::ErrorKind::NotFound,
+                        format!("config.json not found in repository `{url}`"),
+                    )
+                })?;
+
+            json_from_slice(&config).map_err(RegistryError::from)?
+        };
+
+        Ok(Self {
+            _tempdir: tempdir,
+            repo,
+            dl_template: config.dl,
+        })
+    }
+}
+
+#[derive(Debug)]
+struct GitRegistryInner {
+    url: GitUrl,
+    git_index: OnceCell<GitIndex>,
+}
+
+#[derive(Clone, Debug)]
+pub struct GitRegistry(Arc<GitRegistryInner>);
+
+impl GitRegistry {
+    pub fn new(url: GitUrl) -> Self {
+        Self(Arc::new(GitRegistryInner {
+            url,
+            git_index: Default::default(),
+        }))
+    }
+
+    /// WARNING: This is a blocking operation.
+    fn find_crate_matched_ver(
+        repo: &Repository,
+        crate_name: &str,
+        (c1, c2): &(CompactString, Option<CompactString>),
+        version_req: &VersionReq,
+    ) -> Result<MatchedVersion, RegistryError> {
+        let mut path = PathBuf::with_capacity(128);
+        path.push(&**c1);
+        if let Some(c2) = c2 {
+            path.push(&**c2);
+        }
+
+        path.push(&*crate_name.to_lowercase());
+        let crate_versions = repo
+            .get_head_commit_entry_data_by_path(path)?
+            .ok_or_else(|| RegistryError::NotFound(crate_name.into()))?;
+
+        MatchedVersion::find(
+            &mut JsonDeserializer::from_slice(&crate_versions).into_iter(),
+            version_req,
+        )
+    }
+
+    pub async fn fetch_crate_matched(
+        &self,
+        client: Client,
+        name: &str,
+        version_req: &VersionReq,
+    ) -> Result<Manifest<Meta>, RegistryError> {
+        let crate_prefix = crate_prefix_components(name)?;
+        let crate_name = name.to_compact_string();
+        let version_req = version_req.clone();
+        let this = self.clone();
+
+        let cancellation_token = GitCancellationToken::default();
+        // Cancel git operation if the future is cancelled (dropped).
+        let cancel_on_drop = cancellation_token.clone().cancel_on_drop();
+
+        let (matched_version, dl_url) = spawn_blocking(move || {
+            let GitIndex {
+                _tempdir: _,
+                repo,
+                dl_template,
+            } = this
+                .0
+                .git_index
+                .get_or_try_init(|| GitIndex::new(this.0.url.clone(), cancellation_token))?;
+
+            let matched_version =
+                Self::find_crate_matched_ver(repo, &crate_name, &crate_prefix, &version_req)?;
+
+            let url = Url::parse(&render_dl_template(
+                dl_template,
+                &crate_name,
+                &crate_prefix,
+                &matched_version,
+            )?)?;
+
+            Ok::<_, RegistryError>((matched_version, url))
+        })
+        .await??;
+
+        // Git operation done, disarm it
+        cancel_on_drop.disarm();
+
+        parse_manifest(client, name, dl_url, matched_version).await
+    }
+}