ref(oci/client): update unpack_archive_layer to take cache; make pub

Signed-off-by: Vaughn Dice <vaughn.dice@fermyon.com>

crates/oci/src/client.rs

@@ -413,7 +413,7 @@ impl Client {
                             this.cache.write_wasm(&bytes, &layer.digest).await?;
                         }
                         ARCHIVE_MEDIATYPE => {
-                            this.unpack_archive_layer(&bytes, &layer.digest).await?;
+                            unpack_archive_layer(&this.cache, &bytes, &layer.digest).await?;
                         }
                         _ => {
                             this.cache.write_data(&bytes, &layer.digest).await?;
@@ -515,44 +515,6 @@ impl Client {
         }
     }
 
-    /// Unpack archive layer into self.cache
-    async fn unpack_archive_layer(
-        &self,
-        bytes: impl AsRef<[u8]>,
-        digest: impl AsRef<str>,
-    ) -> Result<()> {
-        // Write archive layer to cache as usual
-        self.cache.write_data(&bytes, &digest).await?;
-
-        // Unpack archive into a staging dir
-        let path = self
-            .cache
-            .data_file(&digest)
-            .context("unable to read archive layer from cache")?;
-        let staging_dir = tempfile::tempdir()?;
-        crate::utils::unarchive(path.as_ref(), staging_dir.path()).await?;
-
-        // Traverse unpacked contents and if a file, write to cache by digest
-        // (if it doesn't already exist)
-        for entry in WalkDir::new(staging_dir.path()) {
-            let entry = entry?;
-            if entry.file_type().is_file() && !entry.file_type().is_dir() {
-                let bytes = tokio::fs::read(entry.path()).await?;
-                let digest = format!("sha256:{}", sha256::hex_digest_from_bytes(&bytes));
-                if self.cache.data_file(&digest).is_ok() {
-                    tracing::debug!(
-                        "Skipping unpacked asset {:?}; file already exists",
-                        entry.path()
-                    );
-                } else {
-                    tracing::debug!("Adding unpacked asset {:?} to cache", entry.path());
-                    self.cache.write_data(bytes, &digest).await?;
-                }
-            }
-        }
-        Ok(())
-    }
-
     /// Save a credential set containing the registry username and password.
     pub async fn login(
         server: impl AsRef<str>,
@@ -655,6 +617,46 @@ impl Client {
     }
 }
 
+/// Unpack contents of the provided archive layer, represented by bytes and its
+/// corresponding digest, into the provided cache.
+/// A temporary staging directory is created via tempfile::tempdir() to store
+/// the unpacked contents prior to writing to the cache.
+pub async fn unpack_archive_layer(
+    cache: &Cache,
+    bytes: impl AsRef<[u8]>,
+    digest: impl AsRef<str>,
+) -> Result<()> {
+    // Write archive layer to cache as usual
+    cache.write_data(&bytes, &digest).await?;
+
+    // Unpack archive into a staging dir
+    let path = cache
+        .data_file(&digest)
+        .context("unable to read archive layer from cache")?;
+    let staging_dir = tempfile::tempdir()?;
+    crate::utils::unarchive(path.as_ref(), staging_dir.path()).await?;
+
+    // Traverse unpacked contents and if a file, write to cache by digest
+    // (if it doesn't already exist)
+    for entry in WalkDir::new(staging_dir.path()) {
+        let entry = entry?;
+        if entry.file_type().is_file() && !entry.file_type().is_dir() {
+            let bytes = tokio::fs::read(entry.path()).await?;
+            let digest = format!("sha256:{}", sha256::hex_digest_from_bytes(&bytes));
+            if cache.data_file(&digest).is_ok() {
+                tracing::debug!(
+                    "Skipping unpacked asset {:?}; file already exists",
+                    entry.path()
+                );
+            } else {
+                tracing::debug!("Adding unpacked asset {:?} to cache", entry.path());
+                cache.write_data(bytes, &digest).await?;
+            }
+        }
+    }
+    Ok(())
+}
+
 fn digest_from_url(manifest_url: &str) -> Option<String> {
     // The URL is in the form "https://host/v2/refname/manifests/sha256:..."
     let manifest_url = Url::parse(manifest_url).ok()?;