pythongh-88745: Add _winapi.CopyFile2 and update shutil.copy2 to use it

Include/internal/pycore_global_strings.h

@@ -58,10 +58,14 @@ struct _Py_global_strings {
 
     struct {
         STRUCT_FOR_ID(CANCELLED)
+        STRUCT_FOR_ID(ExistingFileName)
         STRUCT_FOR_ID(FINISHED)
         STRUCT_FOR_ID(False)
+        STRUCT_FOR_ID(Flags)
         STRUCT_FOR_ID(JSONDecodeError)
+        STRUCT_FOR_ID(NewFileName)
         STRUCT_FOR_ID(PENDING)
+        STRUCT_FOR_ID(ProgressRoutine)
         STRUCT_FOR_ID(Py_Repr)
         STRUCT_FOR_ID(TextIOWrapper)
         STRUCT_FOR_ID(True)

Lib/shutil.py

@@ -42,6 +42,8 @@
 
 if sys.platform == 'win32':
     import _winapi
+else:
+    _winapi = None
 
 COPY_BUFSIZE = 1024 * 1024 if _WINDOWS else 64 * 1024
 # This should never be removed, see rationale in:
@@ -435,6 +437,30 @@ def copy2(src, dst, *, follow_symlinks=True):
     """
     if os.path.isdir(dst):
         dst = os.path.join(dst, os.path.basename(src))
+
+    if hasattr(_winapi, "CopyFile2"):
+        src_ = os.fsdecode(src)
+        dst_ = os.fsdecode(dst)
+        flags = _winapi.COPY_FILE_ALLOW_DECRYPTED_DESTINATION # for compat
+        if not follow_symlinks:
+            flags |= _winapi.COPY_FILE_COPY_SYMLINK
+        retry = False
+        try:
+            _winapi.CopyFile2(src_, dst_, flags)
+            return dst
+        except OSError as exc:
+            if (exc.winerror == _winapi.ERROR_PRIVILEGE_NOT_HELD
+                and not follow_symlinks):
+                # Likely encountered a symlink we aren't allowed to create.
+                # Fall back on the old code
+                pass
+            elif exc.winerror == _winapi.ERROR_ACCESS_DENIED:
+                # Possibly encountered a hidden or readonly file we can't
+                # overwrite. Fall back on old code
+                pass
+            else:
+                raise
+
     copyfile(src, dst, follow_symlinks=follow_symlinks)
     copystat(src, dst, follow_symlinks=follow_symlinks)
     return dst

Misc/NEWS.d/next/Windows/2023-05-29-11-38-53.gh-issue-88745.cldf9G.rst

@@ -0,0 +1,3 @@
+Improve performance of :func:`shutil.copy2` by using the operating system's
+``CopyFile2`` function. This may result in subtle changes to metadata copied
+along with some files, bringing them in line with normal OS behavior.

Modules/_winapi.c

@@ -1947,6 +1947,7 @@ _winapi_GetFileType_impl(PyObject *module, HANDLE handle)
     return result;
 }
 
+
 /*[clinic input]
 _winapi._mimetypes_read_windows_registry
 
@@ -2075,6 +2076,59 @@ _winapi_NeedCurrentDirectoryForExePath_impl(PyObject *module,
     return result;
 }
 
+
+/*[clinic input]
+_winapi.CopyFile2
+
+    ExistingFileName: LPCWSTR
+    NewFileName: LPCWSTR
+    Flags: DWORD
+    ProgressRoutine: object = None
+
+Copies a file from one name to a new name.
+
+This is implemented using the CopyFile2 API, which preserves all stat
+and metadata information apart from security attributes.
+
+ProgressRoutine is reserved for future use, but is currently not
+implemented. Its value is ignored.
+[clinic start generated code]*/
+
+static PyObject *
+_winapi_CopyFile2_impl(PyObject *module, LPCWSTR ExistingFileName,
+                       LPCWSTR NewFileName, DWORD Flags,
+                       PyObject *ProgressRoutine)
+/*[clinic end generated code: output=f3f588380da0000a input=13cf59b6e1a70fe6]*/
+{
+    HRESULT hr;
+    COPYFILE2_EXTENDED_PARAMETERS params = { sizeof(COPYFILE2_EXTENDED_PARAMETERS) };
+    params.dwCopyFlags = Flags;
+    /* For future implementation. We ignore the value for now so that
+       users only have to test for 'CopyFile2' existing and not whether
+       the additional parameter exists.
+    if (ProgressRoutine != Py_None) {
+        params.pProgressRoutine = _winapi_CopyFile2ProgressRoutine;
+        params.pvCallbackContext = Py_NewRef(ProgressRoutine);
+    }
+    */
+    Py_BEGIN_ALLOW_THREADS;
+    hr = CopyFile2(ExistingFileName, NewFileName, &params);
+    Py_END_ALLOW_THREADS;
+    /* For future implementation.
+    Py_XDECREF(ProgressRoutine);
+    */
+    if (FAILED(hr)) {
+        if ((hr & 0xFFFF0000) == 0x80070000) {
+            PyErr_SetFromWindowsErr(hr & 0xFFFF);
+        } else {
+            PyErr_SetFromWindowsErr(hr);
+        }
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+
 static PyMethodDef winapi_functions[] = {
     _WINAPI_CLOSEHANDLE_METHODDEF
     _WINAPI_CONNECTNAMEDPIPE_METHODDEF
@@ -2110,6 +2164,7 @@ static PyMethodDef winapi_functions[] = {
     _WINAPI_GETFILETYPE_METHODDEF
     _WINAPI__MIMETYPES_READ_WINDOWS_REGISTRY_METHODDEF
     _WINAPI_NEEDCURRENTDIRECTORYFOREXEPATH_METHODDEF
+    _WINAPI_COPYFILE2_METHODDEF
     {NULL, NULL}
 };
 
@@ -2146,6 +2201,7 @@ static int winapi_exec(PyObject *m)
     WINAPI_CONSTANT(F_DWORD, CREATE_NEW_PROCESS_GROUP);
     WINAPI_CONSTANT(F_DWORD, DUPLICATE_SAME_ACCESS);
     WINAPI_CONSTANT(F_DWORD, DUPLICATE_CLOSE_SOURCE);
+    WINAPI_CONSTANT(F_DWORD, ERROR_ACCESS_DENIED);
     WINAPI_CONSTANT(F_DWORD, ERROR_ALREADY_EXISTS);
     WINAPI_CONSTANT(F_DWORD, ERROR_BROKEN_PIPE);
     WINAPI_CONSTANT(F_DWORD, ERROR_IO_PENDING);
@@ -2159,6 +2215,7 @@ static int winapi_exec(PyObject *m)
     WINAPI_CONSTANT(F_DWORD, ERROR_OPERATION_ABORTED);
     WINAPI_CONSTANT(F_DWORD, ERROR_PIPE_BUSY);
     WINAPI_CONSTANT(F_DWORD, ERROR_PIPE_CONNECTED);
+    WINAPI_CONSTANT(F_DWORD, ERROR_PRIVILEGE_NOT_HELD);
     WINAPI_CONSTANT(F_DWORD, ERROR_SEM_TIMEOUT);
     WINAPI_CONSTANT(F_DWORD, FILE_FLAG_FIRST_PIPE_INSTANCE);
     WINAPI_CONSTANT(F_DWORD, FILE_FLAG_OVERLAPPED);
@@ -2252,6 +2309,34 @@ static int winapi_exec(PyObject *m)
     WINAPI_CONSTANT(F_DWORD, LCMAP_TRADITIONAL_CHINESE);
     WINAPI_CONSTANT(F_DWORD, LCMAP_UPPERCASE);
 
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_ALLOW_DECRYPTED_DESTINATION);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_COPY_SYMLINK);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_FAIL_IF_EXISTS);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_NO_BUFFERING);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_NO_OFFLOAD);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_OPEN_SOURCE_FOR_WRITE);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_RESTARTABLE);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_REQUEST_SECURITY_PRIVILEGES);
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_RESUME_FROM_PAUSE);
+#ifndef COPY_FILE_REQUEST_COMPRESSED_TRAFFIC
+    // Only defined in newer WinSDKs
+    #define COPY_FILE_REQUEST_COMPRESSED_TRAFFIC 0x10000000
+#endif
+    WINAPI_CONSTANT(F_DWORD, COPY_FILE_REQUEST_COMPRESSED_TRAFFIC);
+
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_CHUNK_STARTED);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_CHUNK_FINISHED);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_STREAM_STARTED);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_STREAM_FINISHED);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_POLL_CONTINUE);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_ERROR);
+
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_PROGRESS_CONTINUE);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_PROGRESS_CANCEL);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_PROGRESS_STOP);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_PROGRESS_QUIET);
+    WINAPI_CONSTANT(F_DWORD, COPYFILE2_PROGRESS_PAUSE);
+
     WINAPI_CONSTANT("i", NULL);
 
     return 0;