refactor(downloader): turn DownloadManager into downloader registry

Reshape DownloadManager from a hard-coded VCS match into a registry of
DownloaderInterface instances keyed by source type, mirroring
Composer's DownloadManager — with prefer-source/dist preferences, an
IO handle, and a files cache. ArchiveManager now resolves dist
sources through a shared DownloadManager instead of calling
download_dist directly, and Composer::require / try_load take an IO
so it flows through the factory wiring.

2 files changed, 4 insertions, 8 deletions

diff --git a/crates/mozart-core/src/repository/downloader.rs b/crates/mozart-core/src/repository/downloader.rs
index 56b3652..f2e33a7 100644
--- a/crates/mozart-core/src/repository/downloader.rs
+++ b/crates/mozart-core/src/repository/downloader.rs
@@ -80,7 +80,7 @@ impl DownloadProgress {
 /// Downloaded bytes are cached by URL in `files_cache`; cache hits skip the network request
 /// entirely.
 #[tracing::instrument(skip(expected_shasum, progress, files_cache))]
-pub async fn download_dist(
+pub(crate) async fn download_dist(
     url: &str,
     expected_shasum: Option<&str>,
     progress: Option<&mut DownloadProgress>,
diff --git a/crates/mozart-core/src/repository/installer_executor/filesystem.rs b/crates/mozart-core/src/repository/installer_executor/filesystem.rs
index 2b34e02..05143a0 100644
--- a/crates/mozart-core/src/repository/installer_executor/filesystem.rs
+++ b/crates/mozart-core/src/repository/installer_executor/filesystem.rs
@@ -146,22 +146,18 @@ fn install_from_source(
     match source_type {
         "git" => {
             let process = crate::vcs::process::ProcessExecutor::new();
-            let git_util =
-                crate::vcs::util::git::GitUtil::new(process, vendor_dir.join(".cache").join("git"));
-            let downloader = GitDownloader::new(git_util);
+            let downloader = GitDownloader::new(process, vendor_dir.join(".cache").join("git"));
             downloader.download(url, reference, &target)?;
             downloader.install(url, reference, &target)?;
         }
         "svn" => {
             let process = crate::vcs::process::ProcessExecutor::new();
-            let svn_util = crate::vcs::util::svn::SvnUtil::new(process);
-            let downloader = SvnDownloader::new(svn_util);
+            let downloader = SvnDownloader::new(process);
             downloader.install(url, reference, &target)?;
         }
         "hg" => {
             let process = crate::vcs::process::ProcessExecutor::new();
-            let hg_util = crate::vcs::util::hg::HgUtil::new(process);
-            let downloader = HgDownloader::new(hg_util);
+            let downloader = HgDownloader::new(process);
             downloader.install(url, reference, &target)?;
         }
         _ => {