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Issue #13392: Writing a pyc file should now be atomic under Windows as well.

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This commit is contained in:
Antoine Pitrou 2011-11-15 19:15:19 +01:00
parent 5f7f6150c3
commit 28e401e717
3 changed files with 62 additions and 27 deletions
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48
Python/import.c
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@ -1197,6 +1197,8 @@ write_compiled_module(PyCodeObject *co, PyObject *cpathname,
time_t mtime = srcstat->st_mtime;
#ifdef MS_WINDOWS /* since Windows uses different permissions */
mode_t mode = srcstat->st_mode & ~S_IEXEC;
PyObject *cpathname_tmp;
Py_ssize_t cpathname_len;
#else
mode_t dirmode = (srcstat->st_mode |
S_IXUSR | S_IXGRP | S_IXOTH |
@ -1255,18 +1257,29 @@ write_compiled_module(PyCodeObject *co, PyObject *cpathname,
}
Py_DECREF(dirname);
/* We first write to a tmp file and then take advantage
of atomic renaming (which *should* be true even under Windows). */
#ifdef MS_WINDOWS
(void)DeleteFileW(PyUnicode_AS_UNICODE(cpathname));
fd = _wopen(PyUnicode_AS_UNICODE(cpathname),
O_EXCL | O_CREAT | O_WRONLY | O_TRUNC | O_BINARY,
mode);
cpathname_len = PyUnicode_GET_LENGTH(cpathname);
cpathname_tmp = PyUnicode_New(cpathname_len + 4,
PyUnicode_MAX_CHAR_VALUE(cpathname));
if (cpathname_tmp == NULL) {
PyErr_Clear();
return;
}
PyUnicode_WriteChar(cpathname_tmp, cpathname_len + 0, '.');
PyUnicode_WriteChar(cpathname_tmp, cpathname_len + 1, 't');
PyUnicode_WriteChar(cpathname_tmp, cpathname_len + 2, 'm');
PyUnicode_WriteChar(cpathname_tmp, cpathname_len + 3, 'p');
(void)DeleteFileW(PyUnicode_AS_UNICODE(cpathname_tmp));
fd = _wopen(PyUnicode_AS_UNICODE(cpathname_tmp),
O_EXCL | O_CREAT | O_WRONLY | O_BINARY,
mode);
if (0 <= fd)
fp = fdopen(fd, "wb");
else
fp = NULL;
#else
/* Under POSIX, we first write to a tmp file and then take advantage
of atomic renaming. */
cpathbytes = PyUnicode_EncodeFSDefault(cpathname);
if (cpathbytes == NULL) {
PyErr_Clear();
@ -1294,7 +1307,9 @@ write_compiled_module(PyCodeObject *co, PyObject *cpathname,
if (Py_VerboseFlag)
PySys_FormatStderr(
"# can't create %R\n", cpathname);
#ifndef MS_WINDOWS
#ifdef MS_WINDOWS
Py_DECREF(cpathname_tmp);
#else
Py_DECREF(cpathbytes);
Py_DECREF(cpathbytes_tmp);
#endif
@ -1315,7 +1330,8 @@ write_compiled_module(PyCodeObject *co, PyObject *cpathname,
/* Don't keep partial file */
fclose(fp);
#ifdef MS_WINDOWS
(void)DeleteFileW(PyUnicode_AS_UNICODE(cpathname));
(void)DeleteFileW(PyUnicode_AS_UNICODE(cpathname_tmp));
Py_DECREF(cpathname_tmp);
#else
(void) unlink(PyBytes_AS_STRING(cpathbytes_tmp));
Py_DECREF(cpathbytes);
@ -1324,8 +1340,20 @@ write_compiled_module(PyCodeObject *co, PyObject *cpathname,
return;
}
fclose(fp);
/* Under POSIX, do an atomic rename */
#ifndef MS_WINDOWS
/* Do a (hopefully) atomic rename */
#ifdef MS_WINDOWS
if (!MoveFileExW(PyUnicode_AS_UNICODE(cpathname_tmp),
PyUnicode_AS_UNICODE(cpathname),
MOVEFILE_REPLACE_EXISTING)) {
if (Py_VerboseFlag)
PySys_FormatStderr("# can't write %R\n", cpathname);
/* Don't keep tmp file */
(void) DeleteFileW(PyUnicode_AS_UNICODE(cpathname_tmp));
Py_DECREF(cpathname_tmp);
return;
}
Py_DECREF(cpathname_tmp);
#else
if (rename(PyBytes_AS_STRING(cpathbytes_tmp),
PyBytes_AS_STRING(cpathbytes))) {
if (Py_VerboseFlag)