Fix the memory leak related to Python 3 unicode and char * conversion.

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@11160 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -1,6 +1,21 @@
 Version 1.3.39 (in progress)
 ============================
 
+2009-03-19: bhy
+            [Python] Fix the memory leak related to Python 3 unicode and C char* conversion,
+            which can be shown in the following example before this fix:
+            
+                  from li_cstring import *
+                  i=0
+                  while True:
+                      i += 1
+                      n = str(i)*10
+                      test3(n)
+
+            This fix affected SWIG_AsCharPtrAndSize() so you cannot call this function with
+            a null alloc and non-null cptr argument in Python 3, otherwise a runtime error
+            will be raised.
+
 2009-03-18: wsfulton
 	    [C#] std::vector<T> wrapper improvements for .NET 2 and also providing the
 	    necessary machinery to use the std::vector<T> wrappers with more advanced features such

Lib/python/pyerrors.swg

@@ -55,11 +55,13 @@ SWIG_Python_AddErrorMsg(const char* mesg)
 
   if (PyErr_Occurred()) PyErr_Fetch(&type, &value, &traceback);
   if (value) {
+    char *tmp;
     PyObject *old_str = PyObject_Str(value);
     PyErr_Clear();
     Py_XINCREF(type);
 
-    PyErr_Format(type, "%s %s", SWIG_Python_str_AsChar(old_str), mesg);
+    PyErr_Format(type, "%s %s", tmp = SWIG_Python_str_AsChar(old_str), mesg);
+    SWIG_Python_str_DelForPy3(tmp);
     Py_DECREF(old_str);
     Py_DECREF(value);
   } else {

Lib/python/pyhead.swg

@@ -21,17 +21,35 @@
 #  define SWIG_Python_str_FromFormat PyString_FromFormat
 #endif
 
+
+/* Warning: This function will allocate a new string in Python 3,
+ * so please call SWIG_Python_str_DelForPy3(x) to free the space.
+ */
 SWIGINTERN char*
 SWIG_Python_str_AsChar(PyObject *str)
 {
 #if PY_VERSION_HEX >= 0x03000000
+  char *cstr;
+  char *newstr;
+  int len;
   str = PyUnicode_AsUTF8String(str);
-  return PyBytes_AsString(str);
+  PyBytes_AsStringAndSize(str, &cstr, &len);
+  newstr = (char *) malloc(len+1);
+  memcpy(newstr, cstr, len+1);
+  Py_XDECREF(str);
+  return newstr;
 #else
   return PyString_AsString(str);
 #endif
 }
 
+#if PY_VERSION_HEX >= 0x03000000
+#  define SWIG_Python_str_DelForPy3(x) free( (void*) (x) )
+#else
+#  define SWIG_Python_str_DelForPy3(x) 
+#endif
+
+
 SWIGINTERN PyObject*
 SWIG_Python_str_FromChar(const char *c)
 {

Lib/python/pyinit.swg

@@ -80,9 +80,11 @@ swig_varlink_str(swig_varlinkobject *v) {
 
 SWIGINTERN int
 swig_varlink_print(swig_varlinkobject *v, FILE *fp, int SWIGUNUSEDPARM(flags)) {
+  char *tmp;
   PyObject *str = swig_varlink_str(v);
   fprintf(fp,"Swig global variables ");
-  fprintf(fp,"%s\n", SWIG_Python_str_AsChar(str));
+  fprintf(fp,"%s\n", tmp = SWIG_Python_str_AsChar(str));
+  SWIG_Python_str_DelForPy3(tmp);
   Py_DECREF(str);
   return 0;
 }

Lib/python/pyrun.swg

@@ -407,13 +407,16 @@ SwigPyObject_repr(SwigPyObject *v, PyObject *args)
 SWIGRUNTIME int
 SwigPyObject_print(SwigPyObject *v, FILE *fp, int SWIGUNUSEDPARM(flags))
 {
+  char *str;
 #ifdef METH_NOARGS
   PyObject *repr = SwigPyObject_repr(v);
 #else
   PyObject *repr = SwigPyObject_repr(v, NULL);
 #endif
   if (repr) {
-    fputs(SWIG_Python_str_AsChar(repr), fp);
+    str = SWIG_Python_str_AsChar(repr); 
+    fputs(str, fp);
+    SWIG_Python_str_DelForPy3(str);
     Py_DECREF(repr);
     return 0; 
   } else {
@@ -1474,21 +1477,23 @@ SWIG_Python_TypeQuery(const char *type)
 
 SWIGRUNTIME int
 SWIG_Python_AddErrMesg(const char* mesg, int infront)
-{
+{  
   if (PyErr_Occurred()) {
     PyObject *type = 0;
     PyObject *value = 0;
     PyObject *traceback = 0;
     PyErr_Fetch(&type, &value, &traceback);
     if (value) {
+      char *tmp;
       PyObject *old_str = PyObject_Str(value);
       Py_XINCREF(type);
       PyErr_Clear();
       if (infront) {
-	PyErr_Format(type, "%s %s", mesg, SWIG_Python_str_AsChar(old_str));
+	PyErr_Format(type, "%s %s", mesg, tmp = SWIG_Python_str_AsChar(old_str));
       } else {
-	PyErr_Format(type, "%s %s", SWIG_Python_str_AsChar(old_str), mesg);
+	PyErr_Format(type, "%s %s", tmp = SWIG_Python_str_AsChar(old_str), mesg);
       }
+      SWIG_Python_str_DelForPy3(tmp);
       Py_DECREF(old_str);
     }
     return 1;
@@ -1540,6 +1545,7 @@ SWIG_Python_TypeError(const char *type, PyObject *obj)
 	if (cstr) {
 	  PyErr_Format(PyExc_TypeError, "a '%s' is expected, '%s(%s)' is received",
 		       type, otype, cstr);
+          SWIG_Python_str_DelForPy3(cstr);
 	} else {
 	  PyErr_Format(PyExc_TypeError, "a '%s' is expected, '%s' is received",
 		       type, otype);

Lib/python/pystrings.swg

@@ -6,19 +6,27 @@ SWIGINTERN int
 SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
 {
 %#if PY_VERSION_HEX>=0x03000000
-  if (PyUnicode_Check(obj)) 
+  if (PyUnicode_Check(obj))
 %#else  
-  if (PyString_Check(obj)) 
+  if (PyString_Check(obj))
 %#endif
   {
     char *cstr; Py_ssize_t len;
 %#if PY_VERSION_HEX>=0x03000000
+    if (!alloc && cptr) {
+        /* We can't allow converting without allocation, since the internal
+           representation of string in Python 3 is UCS-2/UCS-4 but we require
+           a UTF-8 representation.
+           TODO(bhy) More detailed explanation */
+        return SWIG_RuntimeError;
+    }
     obj = PyUnicode_AsUTF8String(obj);
     PyBytes_AsStringAndSize(obj, &cstr, &len);
+    if(alloc) *alloc = SWIG_NEWOBJ;
 %#else
     PyString_AsStringAndSize(obj, &cstr, &len);
 %#endif
-    if (cptr) { 
+    if (cptr) {
       if (alloc) {
 	/* 
 	   In python the user should not be able to modify the inner
@@ -43,10 +51,16 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
 	  *alloc = SWIG_OLDOBJ;
 	}
       } else {
+        %#if PY_VERSION_HEX>=0x03000000
+        assert(0); /* Should never reach here in Python 3 */
+        %#endif
 	*cptr = SWIG_Python_str_AsChar(obj);
       }
     }
     if (psize) *psize = len + 1;
+%#if PY_VERSION_HEX>=0x03000000
+    Py_XDECREF(obj);
+%#endif
     return SWIG_OK;
   } else {
     swig_type_info* pchar_descriptor = SWIG_pchar_descriptor();