[Python-checkins] cpython: Issue #16475: Simplify the interface to r_ref_allocate and improve comments.

Wed Mar 20 23:01:41 CET 2013

http://hg.python.org/cpython/rev/f4c21179690b
changeset: 82847:f4c21179690b
user: Kristján Valur Jónsson <sweskman at gmail.com>
date: Wed Mar 20 11:43:57 2013 -0700
summary:
 Issue #16475: Simplify the interface to r_ref_allocate and improve comments.
files:
 Python/marshal.c | 59 ++++++++++++++++++++---------------
 1 files changed, 33 insertions(+), 26 deletions(-)

diff --git a/Python/marshal.c b/Python/marshal.c
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -743,34 +743,37 @@
 return NULL;
 }
 
-/* allocate the reflist index */
-static PyObject *
-r_ref_reserve(PyObject *o, Py_ssize_t *idx, int flag, RFILE *p)
+/* allocate the reflist index for a new object. Return -1 on failure */
+static Py_ssize_t
+r_ref_reserve(int flag, RFILE *p)
 {
 if (flag) { /* currently only FLAG_REF is defined */
- *idx = PyList_Size(p->refs);
- if (*idx < 0)
- goto err;
- if (*idx >= 0x7ffffffe) {
+ Py_ssize_t idx = PyList_Size(p->refs);
+ if (idx < 0)
+ return -1;
+ if (idx >= 0x7ffffffe) {
 PyErr_SetString(PyExc_ValueError, "bad marshal data (index list too large)");
- goto err;
+ return -1;
 }
 if (PyList_Append(p->refs, Py_None) < 0)
- goto err;
+ return -1;
+ return idx;
 } else
- *idx = 0;
- return o;
-err:
- Py_XDECREF(o); /* release the new object */
- *idx = -1;
- return NULL;
+ return 0;
 }
 
-/* insert actual object to the reflist */
+/* insert the new object 'o' to the reflist at previously
+ * allocated index 'idx'.
+ * 'o' can be NULL, in which case nothing is done.
+ * if 'o' was non-NULL, and the function succeeds, 'o' is returned.
+ * if 'o' was non-NULL, and the function fails, 'o' is released and
+ * NULL returned. This simplifies error checking at the call site since
+ * a single test for NULL for the function result is enough.
+ */
 static PyObject *
 r_ref_insert(PyObject *o, Py_ssize_t idx, int flag, RFILE *p)
 {
- if (o && (flag & FLAG_REF)) {
+ if (o != NULL && flag) { /* currently only FLAG_REF is defined */
 if (PyList_SetItem(p->refs, idx, o) < 0) {
 Py_DECREF(o); /* release the new object */
 return NULL;
@@ -788,7 +791,7 @@
 static PyObject *
 r_ref(PyObject *o, int flag, RFILE *p)
 {
- if (o && (flag & FLAG_REF)) {
+ if (o != NULL && flag) { /* currently only FLAG_REF is defined */
 if (PyList_Append(p->refs, o) < 0) {
 Py_DECREF(o); /* release the new object */
 return NULL;
@@ -821,7 +824,8 @@
 type = type & ~FLAG_REF;
 
 #define R_REF(O) do{\
- O = r_ref(O, flag, p);\
+ if (flag) \
+ O = r_ref(O, flag, p);\
 } while (0)
 
 switch (type) {
@@ -1143,13 +1147,16 @@
 break;
 }
 v = (type == TYPE_SET) ? PySet_New(NULL) : PyFrozenSet_New(NULL);
- /* must use delayed registration of frozensets because they must
- * be init with a refcount of 1
- */
- if (type == TYPE_SET)
+ if (type == TYPE_SET) {
 R_REF(v);
- else
- v = r_ref_reserve(v, &idx, flag, p);
+ } else {
+ /* must use delayed registration of frozensets because they must
+ * be init with a refcount of 1
+ */
+ idx = r_ref_reserve(flag, p);
+ if (idx < 0)
+ Py_CLEAR(v); /* signal error */
+ }
 if (v == NULL) {
 retval = NULL;
 break;
@@ -1195,7 +1202,7 @@
 int firstlineno;
 PyObject *lnotab = NULL;
 
- r_ref_reserve(NULL, &idx, flag, p);
+ idx = r_ref_reserve(flag, p);
 if (idx < 0) {
 retval = NULL;
 break;
-- 
Repository URL: http://hg.python.org/cpython
