[Python-checkins] bpo-36387: Refactor getenvironment() in _winapi.c. (GH-12482)

Thu Mar 28 10:01:40 EDT 2019

https://github.com/python/cpython/commit/8abd7c7e37714ce0c42f871f81e52f14c155d1bd
commit: 8abd7c7e37714ce0c42f871f81e52f14c155d1bd
branch: master
author: Serhiy Storchaka <storchaka at gmail.com>
committer: GitHub <noreply at github.com>
date: 2019年03月28日T16:01:34+02:00
summary:
bpo-36387: Refactor getenvironment() in _winapi.c. (GH-12482)
Make it doing less memory allocations and using the modern C API.
files:
M Modules/_winapi.c

diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index e7b221d888ef..2eb708e9073e 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -752,12 +752,12 @@ gethandle(PyObject* obj, const char* name)
 return ret;
 }
 
-static PyObject*
+static wchar_t *
 getenvironment(PyObject* environment)
 {
 Py_ssize_t i, envsize, totalsize;
- Py_UCS4 *buffer = NULL, *p, *end;
- PyObject *keys, *values, *res;
+ wchar_t *buffer = NULL, *p, *end;
+ PyObject *keys, *values;
 
 /* convert environment dictionary to windows environment string */
 if (! PyMapping_Check(environment)) {
@@ -775,8 +775,8 @@ getenvironment(PyObject* environment)
 goto error;
 }
 
- envsize = PySequence_Fast_GET_SIZE(keys);
- if (PySequence_Fast_GET_SIZE(values) != envsize) {
+ envsize = PyList_GET_SIZE(keys);
+ if (PyList_GET_SIZE(values) != envsize) {
 PyErr_SetString(PyExc_RuntimeError,
 "environment changed size during iteration");
 goto error;
@@ -784,8 +784,9 @@ getenvironment(PyObject* environment)
 
 totalsize = 1; /* trailing null character */
 for (i = 0; i < envsize; i++) {
- PyObject* key = PySequence_Fast_GET_ITEM(keys, i);
- PyObject* value = PySequence_Fast_GET_ITEM(values, i);
+ PyObject* key = PyList_GET_ITEM(keys, i);
+ PyObject* value = PyList_GET_ITEM(values, i);
+ Py_ssize_t size;
 
 if (! PyUnicode_Check(key) || ! PyUnicode_Check(value)) {
 PyErr_SetString(PyExc_TypeError,
@@ -806,19 +807,25 @@ getenvironment(PyObject* environment)
 PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
 goto error;
 }
- if (totalsize > PY_SSIZE_T_MAX - PyUnicode_GET_LENGTH(key) - 1) {
+
+ size = PyUnicode_AsWideChar(key, NULL, 0);
+ assert(size > 1);
+ if (totalsize > PY_SSIZE_T_MAX - size) {
 PyErr_SetString(PyExc_OverflowError, "environment too long");
 goto error;
 }
- totalsize += PyUnicode_GET_LENGTH(key) + 1; /* +1 for '=' */
- if (totalsize > PY_SSIZE_T_MAX - PyUnicode_GET_LENGTH(value) - 1) {
+ totalsize += size; /* including '=' */
+
+ size = PyUnicode_AsWideChar(value, NULL, 0);
+ assert(size > 0);
+ if (totalsize > PY_SSIZE_T_MAX - size) {
 PyErr_SetString(PyExc_OverflowError, "environment too long");
 goto error;
 }
- totalsize += PyUnicode_GET_LENGTH(value) + 1; /* +1 for '0円' */
+ totalsize += size; /* including trailing '0円' */
 }
 
- buffer = PyMem_NEW(Py_UCS4, totalsize);
+ buffer = PyMem_NEW(wchar_t, totalsize);
 if (! buffer) {
 PyErr_NoMemory();
 goto error;
@@ -827,34 +834,25 @@ getenvironment(PyObject* environment)
 end = buffer + totalsize;
 
 for (i = 0; i < envsize; i++) {
- PyObject* key = PySequence_Fast_GET_ITEM(keys, i);
- PyObject* value = PySequence_Fast_GET_ITEM(values, i);
- if (!PyUnicode_AsUCS4(key, p, end - p, 0))
- goto error;
- p += PyUnicode_GET_LENGTH(key);
- *p++ = '=';
- if (!PyUnicode_AsUCS4(value, p, end - p, 0))
- goto error;
- p += PyUnicode_GET_LENGTH(value);
- *p++ = '0円';
+ PyObject* key = PyList_GET_ITEM(keys, i);
+ PyObject* value = PyList_GET_ITEM(values, i);
+ Py_ssize_t size = PyUnicode_AsWideChar(key, p, end - p);
+ assert(1 <= size && size < end - p);
+ p += size;
+ *p++ = L'=';
+ size = PyUnicode_AsWideChar(value, p, end - p);
+ assert(0 <= size && size < end - p);
+ p += size + 1;
 }
 
- /* add trailing null byte */
- *p++ = '0円';
+ /* add trailing null character */
+ *p++ = L'0円';
 assert(p == end);
 
- Py_XDECREF(keys);
- Py_XDECREF(values);
-
- res = PyUnicode_FromKindAndData(PyUnicode_4BYTE_KIND, buffer, p - buffer);
- PyMem_Free(buffer);
- return res;
-
 error:
- PyMem_Free(buffer);
 Py_XDECREF(keys);
 Py_XDECREF(values);
- return NULL;
+ return buffer;
 }
 
 static LPHANDLE
@@ -1053,8 +1051,7 @@ _winapi_CreateProcess_impl(PyObject *module,
 BOOL result;
 PROCESS_INFORMATION pi;
 STARTUPINFOEXW si;
- PyObject *environment = NULL;
- wchar_t *wenvironment;
+ wchar_t *wenvironment = NULL;
 wchar_t *command_line_copy = NULL;
 AttributeList attribute_list = {0};
 
@@ -1071,20 +1068,11 @@ _winapi_CreateProcess_impl(PyObject *module,
 goto cleanup;
 
 if (env_mapping != Py_None) {
- environment = getenvironment(env_mapping);
- if (environment == NULL) {
- goto cleanup;
- }
- /* contains embedded null characters */
- wenvironment = PyUnicode_AsUnicode(environment);
+ wenvironment = getenvironment(env_mapping);
 if (wenvironment == NULL) {
 goto cleanup;
 }
 }
- else {
- environment = NULL;
- wenvironment = NULL;
- }
 
 if (getattributelist(startup_info, "lpAttributeList", &attribute_list) < 0)
 goto cleanup;
@@ -1131,7 +1119,7 @@ _winapi_CreateProcess_impl(PyObject *module,
 
 cleanup:
 PyMem_Free(command_line_copy);
- Py_XDECREF(environment);
+ PyMem_Free(wenvironment);
 freeattributelist(&attribute_list);
 
 return ret;
