Split crates and clean up structure of codebase (#294)

Co-authored-by: Jiahao XU <Jiahao_XU@outlook.com>

crates/lib/src/drivers/crates_io.rs

@@ -0,0 +1,62 @@
+use std::path::PathBuf;
+
+use cargo_toml::Manifest;
+use crates_io_api::AsyncClient;
+use log::debug;
+use reqwest::Client;
+use semver::VersionReq;
+use url::Url;
+
+use crate::{
+    errors::BinstallError,
+    helpers::download::download_tar_based_and_visit,
+    manifests::cargo_toml_binstall::{Meta, TarBasedFmt},
+};
+
+use super::find_version;
+
+mod vfs;
+
+mod visitor;
+use visitor::ManifestVisitor;
+
+/// Fetch a crate Cargo.toml by name and version from crates.io
+pub async fn fetch_crate_cratesio(
+    client: &Client,
+    crates_io_api_client: &AsyncClient,
+    name: &str,
+    version_req: &VersionReq,
+) -> Result<Manifest<Meta>, BinstallError> {
+    // Fetch / update index
+    debug!("Looking up crate information");
+
+    // Fetch online crate information
+    let base_info = crates_io_api_client
+        .get_crate(name.as_ref())
+        .await
+        .map_err(|err| BinstallError::CratesIoApi {
+            crate_name: name.into(),
+            err,
+        })?;
+
+    // Locate matching version
+    let version_iter = base_info.versions.iter().filter(|v| !v.yanked);
+    let (version, version_name) = find_version(version_req, version_iter)?;
+
+    debug!("Found information for crate version: '{}'", version.num);
+
+    // Download crate to temporary dir (crates.io or git?)
+    let crate_url = format!("https://crates.io/{}", version.dl_path);
+
+    debug!("Fetching crate from: {crate_url} and extracting Cargo.toml from it");
+
+    let manifest_dir_path: PathBuf = format!("{name}-{version_name}").into();
+
+    download_tar_based_and_visit(
+        client,
+        Url::parse(&crate_url)?,
+        TarBasedFmt::Tgz,
+        ManifestVisitor::new(manifest_dir_path),
+    )
+    .await
+}