From f4a004786500d80e1b47728d216aed9d76869a9d Mon Sep 17 00:00:00 2001
From: Kohya S <ykumeykume@gmail.com>
Date: Wed, 26 Feb 2025 20:50:44 +0900
Subject: [PATCH] feat: support metadata loading in MemoryEfficientSafeOpen

---
 library/utils.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/library/utils.py b/library/utils.py
index 07079c6d..4df8bd32 100644
--- a/library/utils.py
+++ b/library/utils.py
@@ -261,11 +261,10 @@ def mem_eff_save_file(tensors: Dict[str, torch.Tensor], filename: str, metadata:
 
 
 class MemoryEfficientSafeOpen:
-    # does not support metadata loading
     def __init__(self, filename):
         self.filename = filename
-        self.header, self.header_size = self._read_header()
         self.file = open(filename, "rb")
+        self.header, self.header_size = self._read_header()
 
     def __enter__(self):
         return self
@@ -276,6 +275,9 @@ class MemoryEfficientSafeOpen:
     def keys(self):
         return [k for k in self.header.keys() if k != "__metadata__"]
 
+    def metadata(self) -> Dict[str, str]:
+        return self.header.get("__metadata__", {})
+
     def get_tensor(self, key):
         if key not in self.header:
             raise KeyError(f"Tensor '{key}' not found in the file")
@@ -293,10 +295,9 @@ class MemoryEfficientSafeOpen:
         return self._deserialize_tensor(tensor_bytes, metadata)
 
     def _read_header(self):
-        with open(self.filename, "rb") as f:
-            header_size = struct.unpack("<Q", f.read(8))[0]
-            header_json = f.read(header_size).decode("utf-8")
-            return json.loads(header_json), header_size
+        header_size = struct.unpack("<Q", self.file.read(8))[0]
+        header_json = self.file.read(header_size).decode("utf-8")
+        return json.loads(header_json), header_size
 
     def _deserialize_tensor(self, tensor_bytes, metadata):
         dtype = self._get_torch_dtype(metadata["dtype"])