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[Swig-cvs] SF.net SVN: swig:[12783] trunk
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From: <wsf...@us...> - 2011-08-23 19:29:17
|
Revision: 12783
http://swig.svn.sourceforge.net/swig/?rev=12783&view=rev
Author: wsfulton
Date: 2011-08-23 19:29:10 +0000 (Tue, 23 Aug 2011)
Log Message:
-----------
Fix %newobject when used in conjunction with %feature(ref). The code from the ref feature was not always being generated for the function specified by %newobject. Documentation for ref and unref moved from Python to the C++ chapter.
Modified Paths:
--------------
trunk/CHANGES.current
trunk/Doc/Manual/Customization.html
trunk/Doc/Manual/Python.html
trunk/Doc/Manual/SWIGPlus.html
trunk/Examples/test-suite/python/refcount_runme.py
trunk/Examples/test-suite/refcount.i
trunk/Source/Swig/cwrap.c
trunk/Source/Swig/typemap.c
Modified: trunk/CHANGES.current
===================================================================
--- trunk/CHANGES.current 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/CHANGES.current 2011-08-23 19:29:10 UTC (rev 12783)
@@ -5,6 +5,11 @@
Version 2.0.5 (in progress)
===========================
+2011-08-23: wsfulton
+ Fix %newobject when used in conjunction with %feature("ref") as reported by Jan Becker. The
+ code from the "ref" feature was not always being generated for the function specified by %newobject.
+ Documentation for "ref" and "unref" moved from Python to the C++ chapter.
+
2011-08-22: szager
[python] Fixed memory leak with --builtin option (bug 3385089).
Modified: trunk/Doc/Manual/Customization.html
===================================================================
--- trunk/Doc/Manual/Customization.html 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Doc/Manual/Customization.html 2011-08-23 19:29:10 UTC (rev 12783)
@@ -705,6 +705,11 @@
</p>
<p>
+The use of <tt>%newobject</tt> is also integrated with reference counting and is covered in the
+<a href="SWIGPlus.html#SWIGPlus_ref_unref">C++ reference counted objects</a> section.
+</p>
+
+<p>
<b>Compatibility note:</b> Previous versions of SWIG had a special <tt>%new</tt> directive. However, unlike <tt>%newobject</tt>,
it only applied to the next declaration. For example:
</p>
Modified: trunk/Doc/Manual/Python.html
===================================================================
--- trunk/Doc/Manual/Python.html 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Doc/Manual/Python.html 2011-08-23 19:29:10 UTC (rev 12783)
@@ -38,7 +38,7 @@
<li><a href="#Python_nn25">C++ namespaces</a>
<li><a href="#Python_nn26">C++ templates</a>
<li><a href="#Python_nn27">C++ Smart Pointers</a>
-<li><a href="#Python_nn27a">C++ Reference Counted Objects (ref/unref)</a>
+<li><a href="#Python_nn27a">C++ reference counted objects</a>
</ul>
<li><a href="#Python_nn28">Further details on the Python class interface</a>
<ul>
@@ -2053,150 +2053,14 @@
</pre>
</div>
+<H3><a name="Python_nn27a"></a>33.3.15 C++ reference counted objects</H3>
-<H3><a name="Python_nn27a"></a>33.3.15 C++ Reference Counted Objects (ref/unref)</H3>
-
-
<p>
-Another usual idiom in C++ is the use of reference counted
-objects. Consider for example:
-
-<div class="code">
-<pre>
-class RCObj {
- // implement the ref counting mechanism
- int add_ref();
- int del_ref();
- int ref_count();
-
-public:
- virtual ~RCObj() = 0;
-
- int ref() const {
- return add_ref();
- }
-
- int unref() const {
- if (ref_count() == 0 || del_ref() == 0 ) {
- delete this;
- return 0;
- }
- return ref_count();
- }
-};
-
-
-class A : RCObj {
-public:
- A();
- int foo();
-};
-
-
-class B {
- A *_a;
-
-public:
- B(A *a) : _a(a) {
- a->ref();
- }
-
- ~B() {
- a->unref();
- }
-};
-
-int main() {
- A *a = new A();
- a->ref(); // 'a' is ref here
-
- B *b1 = new B(a); // 'a' is ref here
- if (1 + 1 == 2) {
- B *b2 = new B(a); // 'a' is ref here
- delete b2; // 'a' is unref, but not deleted
- }
-
- delete b1; // 'a' is unref, but not deleted
- a->unref(); // 'a' is unref and deleted
-}
-</pre>
-</div>
-
-<p>
-In the example above, the 'A' class instance 'a' is a reference counted
-object, which can't be deleted arbitrarily since it is shared between
-the objects 'b1' and 'b2'. 'A' is derived from an Reference Counted
-Object 'RCObj', which implements the ref/unref idiom.
+The <a href="SWIGPlus.html#SWIGPlus_ref_unref">C++ reference counted objects</a> section contains
+Python examples of memory management using referencing counting.
</p>
-<p>
-To tell SWIG that 'RCObj' and all its derived classes are reference
-counted objects, you use the "ref" and "unref" features.
-For example:
-</p>
-
-<div class="code">
-<pre>
-%module example
-...
-
-%feature("ref") RCObj "$this->ref();"
-%feature("unref") RCObj "$this->unref();"
-
-%include "rcobj.h"
-%include "A.h"
-...
-</pre>
-</div>
-
-<p>
-where the code passed to the "ref" and "unref" features will be
-executed as needed whenever a new object is passed to python, or when
-python tries to release the proxy object instance, respectively.
-</p>
-
-<p>
-In the python side, the use of a reference counted object is not
-different than any other regular instance:
-</p>
-
-<div class="targetlang">
-<pre>
-def create_A():
- a = A() # SWIG ref 'a' (new object is passed to python)
- b1 = B(a) # C++ ref 'a'
- if 1 + 1 == 2:
- b2 = B(a) # C++ ref 'a'
- return a # 'b1' and 'b2' are released, C++ unref 'a' twice
-
-a = create_A()
-exit # 'a' is released, SWIG unref 'a'
-</pre>
-</div>
-
-<p>
-Note that the user doesn't explicitly need to call 'a->ref()' nor 'a->unref()'
-(as neither 'delete a'). Instead, SWIG take cares of executing the "ref"
-and "unref" codes as needed. If the user doesn't specify the
-"ref/unref" features, SWIG will produce a code equivalent to define
-them as:
-</p>
-
-<div class="code">
-<pre>
-%feature("ref") ""
-%feature("unref") "delete $this;"
-</pre>
-</div>
-
-<p>
-In other words, SWIG will not do anything special when a new object
-is passed to python, and it will always 'delete' the object when
-python releases the proxy instance.
-</p>
-
-
<H2><a name="Python_nn28"></a>33.4 Further details on the Python class interface</H2>
Modified: trunk/Doc/Manual/SWIGPlus.html
===================================================================
--- trunk/Doc/Manual/SWIGPlus.html 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Doc/Manual/SWIGPlus.html 2011-08-23 19:29:10 UTC (rev 12783)
@@ -4618,7 +4618,181 @@
<b>Note:</b> Smart pointer support was first added in SWIG-1.3.14.
</p>
+<H2><a name="SWIGPlus_ref_unref"></a>C++ reference counted objects - ref/unref feature</H2>
+
+<p>
+Another similar idiom in C++ is the use of reference counted objects. Consider for example:
+
+<div class="code">
+<pre>
+class RCObj {
+ // implement the ref counting mechanism
+ int add_ref();
+ int del_ref();
+ int ref_count();
+
+public:
+ virtual ~RCObj() = 0;
+
+ int ref() const {
+ return add_ref();
+ }
+
+ int unref() const {
+ if (ref_count() == 0 || del_ref() == 0 ) {
+ delete this;
+ return 0;
+ }
+ return ref_count();
+ }
+};
+
+
+class A : RCObj {
+public:
+ A();
+ int foo();
+};
+
+
+class B {
+ A *_a;
+
+public:
+ B(A *a) : _a(a) {
+ a->ref();
+ }
+
+ ~B() {
+ a->unref();
+ }
+};
+
+int main() {
+ A *a = new A(); // (count: 0)
+ a->ref(); // 'a' ref here (count: 1)
+
+ B *b1 = new B(a); // 'a' ref here (count: 2)
+ if (1 + 1 == 2) {
+ B *b2 = new B(a); // 'a' ref here (count: 3)
+ delete b2; // 'a' unref, but not deleted (count: 2)
+ }
+
+ delete b1; // 'a' unref, but not deleted (count: 1)
+ a->unref(); // 'a' unref and deleted (count: 0)
+}
+</pre>
+</div>
+
+<p>
+In the example above, the 'A' class instance 'a' is a reference counted
+object, which can't be deleted arbitrarily since it is shared between
+the objects 'b1' and 'b2'. 'A' is derived from a <i>Reference Counted
+ Object</i> 'RCObj', which implements the ref/unref idiom.
+</p>
+
+<p>
+To tell SWIG that 'RCObj' and all its derived classes are reference
+counted objects, use the "ref" and "unref" <a href="Customization.html#Customization_features">features</a>.
+These are also available as <tt>%refobject</tt> and <tt>%unrefobject</tt>, respectively.
+For example:
+</p>
+
+
+<div class="code">
+<pre>
+%module example
+...
+
+%feature("ref") RCObj "$this->ref();"
+%feature("unref") RCObj "$this->unref();"
+
+%include "rcobj.h"
+%include "A.h"
+...
+</pre>
+</div>
+
+<p>
+where the code passed to the "ref" and "unref" features will be
+executed as needed whenever a new object is passed to python, or when
+python tries to release the proxy object instance, respectively.
+</p>
+
+<p>
+On the python side, the use of a reference counted object is no
+different to any other regular instance:
+</p>
+
+<div class="targetlang">
+<pre>
+def create_A():
+ a = A() # SWIG ref 'a' - new object is passed to python (count: 1)
+ b1 = B(a) # C++ ref 'a (count: 2)
+ if 1 + 1 == 2:
+ b2 = B(a) # C++ ref 'a' (count: 3)
+ return a # 'b1' and 'b2' are released and deleted, C++ unref 'a' twice (count: 1)
+
+a = create_A() # (count: 1)
+exit # 'a' is released, SWIG unref 'a' called in the destructor wrapper (count: 0)
+</pre>
+</div>
+
+<p>
+Note that the user doesn't explicitly need to call 'a->ref()' nor 'a->unref()'
+(and neither 'delete a'). Instead, SWIG takes cares of executing the "ref"
+and "unref" calls as needed. If the user doesn't specify the
+"ref/unref" feature for a type, SWIG will produce code equivalent to defining these
+features:
+</p>
+
+<div class="code">
+<pre>
+%feature("ref") ""
+%feature("unref") "delete $this;"
+</pre>
+</div>
+
+<p>
+In other words, SWIG will not do anything special when a new object
+is passed to python, and it will always 'delete' the underlying object when
+python releases the proxy instance.
+</p>
+
+<p>
+</p>
+
+<p>
+The <a href="Customization.html#Customization_ownership">%newobject feature</a> is designed to indicate to
+the target language that it should take ownership of the returned object.
+When used in conjunction with a type that has the "ref" feature associated with it, it additionally emits the
+code in the "ref" feature into the C++ wrapper.
+Consider wrapping the following factory function in addition to the above:
+</p>
+
+<div class="code">
+<pre>
+%newobject AFactory;
+A *AFactory() {
+ return new A();
+}
+</pre>
+</div>
+
+<p>
+The <tt>AFactory</tt> function now acts much like a call to the <tt>A</tt> constructor with respect to memory handling:
+</p>
+
+<div class="targetlang">
+<pre>
+a = AFactory() # SWIG ref 'a' due to %newobject (count: 1)
+exit # 'a' is released, SWIG unref 'a' called in the destructor wrapper (count: 0)
+</pre>
+</div>
+
+
+
<H2><a name="SWIGPlus_nn35"></a>6.25 Using declarations and inheritance</H2>
Modified: trunk/Examples/test-suite/python/refcount_runme.py
===================================================================
--- trunk/Examples/test-suite/python/refcount_runme.py 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Examples/test-suite/python/refcount_runme.py 2011-08-23 19:29:10 UTC (rev 12783)
@@ -10,14 +10,14 @@
if a.ref_count() != 3:
- print "This program will crash... now"
+ raise RuntimeError("Count = %d" % a.ref_count())
rca = b2.get_rca()
b3 = B.create(rca)
if a.ref_count() != 5:
- print "This program will crash... now"
+ raise RuntimeError("Count = %d" % a.ref_count())
v = vector_A(2)
@@ -27,6 +27,35 @@
x = v[0]
del v
+if a.ref_count() != 6:
+ raise RuntimeError("Count = %d" % a.ref_count())
+# Check %newobject
+b4 = b2.cloner()
+if b4.ref_count() != 1:
+ raise RuntimeError
+b5 = global_create(a)
+if b5.ref_count() != 1:
+ raise RuntimeError
+b6 = Factory.create(a)
+if b6.ref_count() != 1:
+ raise RuntimeError
+
+b7 = Factory().create2(a)
+if b7.ref_count() != 1:
+ raise RuntimeError
+
+
+if a.ref_count() != 10:
+ raise RuntimeError("Count = %d" % a.ref_count())
+
+del b4
+del b5
+del b6
+del b7
+
+if a.ref_count() != 6:
+ raise RuntimeError("Count = %d" % a.ref_count())
+
Modified: trunk/Examples/test-suite/refcount.i
===================================================================
--- trunk/Examples/test-suite/refcount.i 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Examples/test-suite/refcount.i 2011-08-23 19:29:10 UTC (rev 12783)
@@ -8,8 +8,8 @@
%}
//
-// using the %refobject/%unrefobject directives you can active the
-// ref. counting for RCObj and all its descendents at once
+// using the %refobject/%unrefobject directives you can activate the
+// reference counting for RCObj and all its descendents at once
//
%refobject RCObj "$this->addref();"
@@ -18,7 +18,10 @@
%include "refcount.h"
%newobject B::create(A* a);
+%newobject global_create(A* a);
%newobject B::cloner();
+%newobject Factory::create(A* a);
+%newobject Factory::create2(A* a);
@@ -94,6 +97,22 @@
RCPtr<A> _a;
};
+class B* global_create(A* a)
+{
+ return new B(a);
+}
+
+struct Factory {
+ static B* create(A* a)
+ {
+ return new B(a);
+ }
+ B* create2(A* a)
+ {
+ return new B(a);
+ }
+};
+
%}
#if defined(SWIGPYTHON) || defined(SWIGOCTAVE)
Modified: trunk/Source/Swig/cwrap.c
===================================================================
--- trunk/Source/Swig/cwrap.c 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Source/Swig/cwrap.c 2011-08-23 19:29:10 UTC (rev 12783)
@@ -546,7 +546,7 @@
}
/* -----------------------------------------------------------------------------
- * Swig_rflag_search()
+ * recursive_flag_search()
*
* This function searches for the class attribute 'attr' in the class
* 'n' or recursively in its bases.
@@ -567,7 +567,7 @@
* ----------------------------------------------------------------------------- */
/* #define SWIG_FAST_REC_SEARCH 1 */
-String *Swig_rflag_search(Node *n, const String *attr, const String *noattr) {
+static String *recursive_flag_search(Node *n, const String *attr, const String *noattr) {
String *f = 0;
n = Swig_methodclass(n);
if (GetFlag(n, noattr)) {
@@ -581,7 +581,7 @@
if (bl) {
Iterator bi;
for (bi = First(bl); bi.item; bi = Next(bi)) {
- f = Swig_rflag_search(bi.item, attr, noattr);
+ f = recursive_flag_search(bi.item, attr, noattr);
if (f) {
#ifdef SWIG_FAST_REC_SEARCH
SetFlagAttr(n, attr, f);
@@ -600,12 +600,11 @@
/* -----------------------------------------------------------------------------
* Swig_unref_call()
*
- * find the unref call, if any.
+ * Find the "feature:unref" call, if any.
* ----------------------------------------------------------------------------- */
String *Swig_unref_call(Node *n) {
- Node *cn = Swig_methodclass(n);
- String *unref = Swig_rflag_search(cn, "feature:unref", "feature:nounref");
+ String *unref = recursive_flag_search(n, "feature:unref", "feature:nounref");
if (unref) {
String *pname = Swig_cparm_name(0, 0);
unref = NewString(unref);
@@ -619,12 +618,11 @@
/* -----------------------------------------------------------------------------
* Swig_ref_call()
*
- * find the ref call, if any.
+ * Find the "feature:ref" call, if any.
* ----------------------------------------------------------------------------- */
String *Swig_ref_call(Node *n, const String *lname) {
- Node *cn = Swig_methodclass(n);
- String *ref = Swig_rflag_search(cn, "feature:ref", "feature:noref");
+ String *ref = recursive_flag_search(n, "feature:ref", "feature:noref");
if (ref) {
ref = NewString(ref);
Replaceall(ref, "$this", lname);
@@ -642,7 +640,8 @@
* ----------------------------------------------------------------------------- */
String *Swig_cdestructor_call(Node *n) {
- String *unref = Swig_unref_call(n);
+ Node *cn = Swig_methodclass(n);
+ String *unref = Swig_unref_call(cn);
if (unref) {
return unref;
@@ -664,7 +663,8 @@
* ----------------------------------------------------------------------------- */
String *Swig_cppdestructor_call(Node *n) {
- String *unref = Swig_unref_call(n);
+ Node *cn = Swig_methodclass(n);
+ String *unref = Swig_unref_call(cn);
if (unref) {
return unref;
} else {
Modified: trunk/Source/Swig/typemap.c
===================================================================
--- trunk/Source/Swig/typemap.c 2011-08-22 23:33:17 UTC (rev 12782)
+++ trunk/Source/Swig/typemap.c 2011-08-23 19:29:10 UTC (rev 12783)
@@ -1309,15 +1309,21 @@
int optimal_substitution = 0;
int num_substitutions = 0;
- /* special case, we need to check for 'ref' call and set the default code 'sdef' */
- if (node && Cmp(tmap_method, "newfree") == 0) {
- sdef = Swig_ref_call(node, lname);
- }
-
type = Getattr(node, "type");
if (!type)
return sdef;
+ /* Special hook (hack!). Check for the 'ref' feature and add code it contains to any 'newfree' typemap code.
+ * We could choose to put this hook into a number of different typemaps, not necessarily 'newfree'...
+ * Rather confusingly 'newfree' is used to release memory and the 'ref' feature is used to add in memory references - yuck! */
+ if (node && Cmp(tmap_method, "newfree") == 0) {
+ String *base = SwigType_base(type);
+ Node *typenode = Swig_symbol_clookup(base, 0);
+ if (typenode)
+ sdef = Swig_ref_call(typenode, lname);
+ Delete(base);
+ }
+
pname = Getattr(node, "name");
if (pname && node && checkAttribute(node, "kind", "function")) {
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