Fixed bug with NamedTemporaryFile on Windows (#4)

xtarfile/zstd.py

@@ -1,6 +1,7 @@
 from contextlib import contextmanager
 from tarfile import open as tarfile_open
 from tempfile import NamedTemporaryFile
+from os import remove as os_remove
 
 try:
     import zstandard
@@ -14,29 +15,47 @@ def __init__(self, **kwargs):
 
     @contextmanager
     def read(self, path: str, mode: str):
-        with NamedTemporaryFile() as decompressed:
-            with open(path, 'rb') as compressed:
-                zstd = zstandard.ZstdDecompressor(**self.zstd_kwargs)
-                zstd.copy_stream(compressed, decompressed)
-            decompressed.seek(0)
-            archive = tarfile_open(mode=mode, fileobj=decompressed)
-            try:
-                yield archive
-            finally:
-                archive.close()
+        try:
+            with NamedTemporaryFile(delete=False) as decompressed:
+                with open(path, 'rb') as compressed:
+                    zstd = zstandard.ZstdDecompressor(**self.zstd_kwargs)
+                    zstd.copy_stream(compressed, decompressed)
+                decompressed.seek(0)
+                archive = tarfile_open(mode=mode, fileobj=decompressed)
+                try:
+                    yield archive
+                finally:
+                    archive.close()
+        finally:
+            # We delete it manually because otherwise on Windows
+            # it gets deleted before we move it to the output file location.
+            # This is because on Windows, file handles with the O_TEMPORARY
+            # flag (which is set if we pass `delete=True`) are deleted as
+            # soon as they're closed.
+            decompressed.close()
+            os_remove(decompressed.name)
 
     @contextmanager
     def write(self, path: str, mode: str):
-        with NamedTemporaryFile() as decompressed:
-            archive = tarfile_open(decompressed.name, mode=mode)
-            try:
-                yield archive
-            finally:
-                archive.close()
-            decompressed.seek(0)
-            with open(path, 'wb') as compressed:
-                zstd = zstandard.ZstdCompressor(**self.zstd_kwargs)
-                zstd.copy_stream(decompressed, compressed)
+        try:
+            with NamedTemporaryFile(delete=False) as decompressed:
+                archive = tarfile_open(decompressed.name, mode=mode)
+                try:
+                    yield archive
+                finally:
+                    archive.close()
+                decompressed.seek(0)
+                with open(path, 'wb') as compressed:
+                    zstd = zstandard.ZstdCompressor(**self.zstd_kwargs)
+                    zstd.copy_stream(decompressed, compressed)
+        finally:
+            # We delete it manually because otherwise on Windows
+            # it gets deleted before we move it to the output file location.
+            # This is because on Windows, file handles with the O_TEMPORARY
+            # flag (which is set if we pass `delete=True`) are deleted as
+            # soon as they're closed.
+            decompressed.close()
+            os_remove(decompressed.name)
 
 
 if zstandard is None: