1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 // Author: tibell@google.com (Johan Tibell) 32 33 #ifndef GOOGLE_PROTOBUF_PYTHON_CPP_SCOPED_PYOBJECT_PTR_H__ 34 #define GOOGLE_PROTOBUF_PYTHON_CPP_SCOPED_PYOBJECT_PTR_H__ 35 36 #include <google/protobuf/stubs/common.h> 37 38 #include <Python.h> 39 namespace google { 40 namespace protobuf { 41 namespace python { 42 43 // Owns a python object and decrements the reference count on destruction. 44 // This class is not threadsafe. 45 template <typename PyObjectStruct> 46 class ScopedPythonPtr { 47 public: 48 // Takes the ownership of the specified object to ScopedPythonPtr. 49 // The reference count of the specified py_object is not incremented. 50 explicit ScopedPythonPtr(PyObjectStruct* py_object = NULL) ptr_(py_object)51 : ptr_(py_object) {} 52 53 // If a PyObject is owned, decrement its reference count. ~ScopedPythonPtr()54 ~ScopedPythonPtr() { Py_XDECREF(ptr_); } 55 56 // Deletes the current owned object, if any. 57 // Then takes ownership of a new object without incrementing the reference 58 // count. 59 // This function must be called with a reference that you own. 60 // this->reset(this->get()) is wrong! 61 // this->reset(this->release()) is OK. 62 PyObjectStruct* reset(PyObjectStruct* p = NULL) { 63 Py_XDECREF(ptr_); 64 ptr_ = p; 65 return ptr_; 66 } 67 68 // Releases ownership of the object without decrementing the reference count. 69 // The caller now owns the returned reference. release()70 PyObjectStruct* release() { 71 PyObject* p = ptr_; 72 ptr_ = NULL; 73 return p; 74 } 75 get()76 PyObjectStruct* get() const { return ptr_; } 77 as_pyobject()78 PyObject* as_pyobject() const { return reinterpret_cast<PyObject*>(ptr_); } 79 80 // Increments the reference count fo the current object. 81 // Should not be called when no object is held. inc()82 void inc() const { Py_INCREF(ptr_); } 83 84 // True when a ScopedPyObjectPtr and a raw pointer refer to the same object. 85 // Comparison operators are non reflexive. 86 bool operator==(const PyObjectStruct* p) const { return ptr_ == p; } 87 bool operator!=(const PyObjectStruct* p) const { return ptr_ != p; } 88 89 private: 90 PyObjectStruct* ptr_; 91 92 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ScopedPythonPtr); 93 }; 94 95 typedef ScopedPythonPtr<PyObject> ScopedPyObjectPtr; 96 97 } // namespace python 98 } // namespace protobuf 99 } // namespace google 100 #endif // GOOGLE_PROTOBUF_PYTHON_CPP_SCOPED_PYOBJECT_PTR_H__ 101