ref(snapshots): Use file-based upload for objectstore puts (#3185)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: lcian

src/commands/build/snapshots.rs

@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use std::fs::{self, File};
+use std::fs::File;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
 use std::str::FromStr as _;
@@ -212,11 +212,24 @@ fn validate_image_sizes(images: &[ImageInfo]) -> Result<()> {
     Ok(())
 }
 
-fn compute_sha256_hash(data: &[u8]) -> String {
+fn compute_sha256_hash(path: &Path) -> Result<String> {
+    use std::io::Read as _;
+
+    let mut file = std::fs::File::open(path)
+        .with_context(|| format!("Failed to open image for hashing: {}", path.display()))?;
     let mut hasher = Sha256::new();
-    hasher.update(data);
+    let mut buffer = [0u8; 8192];
+    loop {
+        let bytes_read = file
+            .read(&mut buffer)
+            .with_context(|| format!("Failed to read image for hashing: {}", path.display()))?;
+        if bytes_read == 0 {
+            break;
+        }
+        hasher.update(&buffer[..bytes_read]);
+    }
     let result = hasher.finalize();
-    format!("{result:x}")
+    Ok(format!("{result:x}"))
 }
 
 fn is_hidden(root: &Path, path: &Path) -> bool {
@@ -297,15 +310,18 @@ fn upload_images(
     for image in images {
         debug!("Processing image: {}", image.path.display());
 
-        let contents = fs::read(&image.path)
-            .with_context(|| format!("Failed to read image: {}", image.path.display()))?;
-        let hash = compute_sha256_hash(&contents);
+        let hash = compute_sha256_hash(&image.path)?;
+        let file = runtime
+            .block_on(tokio::fs::File::open(&image.path))
+            .with_context(|| {
+                format!("Failed to open image for upload: {}", image.path.display())
+            })?;
 
         info!("Queueing {} as {hash}", image.relative_path.display());
 
         many_builder = many_builder.push(
             session
-                .put(contents)
+                .put_file(file)
                 .key(&hash)
                 .expiration_policy(expiration),
         );