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/visitor.rs

@@ -0,0 +1,81 @@
+use std::path::{Path, PathBuf};
+
+use binstalk_downloader::download::{DownloadError, TarEntriesVisitor, TarEntry};
+use binstalk_types::cargo_toml_binstall::Meta;
+use cargo_toml_workspace::cargo_toml::{Manifest, Value};
+use normalize_path::NormalizePath;
+use tokio::io::AsyncReadExt;
+use tracing::debug;
+
+use crate::{vfs::Vfs, RegistryError};
+
+#[derive(Debug)]
+pub(super) struct ManifestVisitor {
+    cargo_toml_content: Vec<u8>,
+    /// manifest_dir_path is treated as the current dir.
+    manifest_dir_path: PathBuf,
+
+    vfs: Vfs,
+}
+
+impl ManifestVisitor {
+    pub(super) fn new(manifest_dir_path: PathBuf) -> Self {
+        Self {
+            // Cargo.toml is quite large usually.
+            cargo_toml_content: Vec::with_capacity(2000),
+            manifest_dir_path,
+            vfs: Vfs::default(),
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl TarEntriesVisitor for ManifestVisitor {
+    async fn visit(&mut self, entry: &mut dyn TarEntry) -> Result<(), DownloadError> {
+        let path = entry.path()?;
+        let path = path.normalize();
+
+        let path = if let Ok(path) = path.strip_prefix(&self.manifest_dir_path) {
+            path
+        } else {
+            // The path is outside of the curr dir (manifest dir),
+            // ignore it.
+            return Ok(());
+        };
+
+        if path == Path::new("Cargo.toml")
+            || path == Path::new("src/main.rs")
+            || path.starts_with("src/bin")
+        {
+            self.vfs.add_path(path);
+        }
+
+        if path == Path::new("Cargo.toml") {
+            // Since it is possible for the same Cargo.toml to appear
+            // multiple times using `tar --keep-old-files`, here we
+            // clear the buffer first before reading into it.
+            self.cargo_toml_content.clear();
+            self.cargo_toml_content
+                .reserve_exact(entry.size()?.try_into().unwrap_or(usize::MAX));
+            entry.read_to_end(&mut self.cargo_toml_content).await?;
+        }
+
+        Ok(())
+    }
+}
+
+impl ManifestVisitor {
+    /// Load binstall metadata using the extracted information stored in memory.
+    pub(super) fn load_manifest(self) -> Result<Manifest<Meta>, RegistryError> {
+        debug!("Loading manifest directly from extracted file");
+
+        // Load and parse manifest
+        let mut manifest = Manifest::from_slice_with_metadata(&self.cargo_toml_content)?;
+
+        // Checks vfs for binary output names
+        manifest.complete_from_abstract_filesystem::<Value, _>(&self.vfs, None)?;
+
+        // Return metadata
+        Ok(manifest)
+    }
+}