Question

我有一个类python脚本。

import sqlite3
from db_layer_core import DbTableCore

class ItemTable(DbTableCore):
    q_create = """create table item_table ( 
        item_id text primary key not null, 
        name text not null, 
        description text )"""
    q_drop = 'drop table item_table'
    q_select = 'select item_id, name, description from item_table'
    q_insert = 'insert into item_table(item_id, name, description) values (?, ?, ?)'
    q_update = 'update item_table set name = ? , description = ? where item_id = ?'

    def create_table(self):
        try:
            with sqlite3.connect('p_storage.db') as db_conn:
                db_conn.execute(q_create)
        except sqlite3.OperationalError:
            print 'such table exists'

    def drop_table(self):
        try:
            with sqlite3.connect('p_storage.db') as db_conn:
                db_conn.execute(q_drop)
        except sqlite3.OperationalError:
            print 'such table probably does not exist'

    def insert_items(items):
        with sqlite3.connect('p_storage.db') as db_conn:
            for row in items:
                db_conn.execute(q_insert, (row[0], row[1], row[2]))
                db_conn.commit()

    def select_items(self):
        with sqlite3.connect('p_storage.db') as db_conn:      
            cursor = db_conn.execute(q_select)
            for row in cursor:
                print row

    def update_items(items):
        with sqlite3.connect('p_storage.db') as db_conn:
            for row in items:
                db_conn.execute(q_update, (row[0], row[1],  row[2]))
                db_conn.commit()

db_layer_core文件看起来像这样

from abc import ABCMeta, abstractmethod

class DbTableCore:
    __metaclass__ = ABCMeta

    @abstractmethod
    def create_table(self):
        return

    @abstractmethod
    def drop_table(self):
        return

    @abstractmethod
    def insert_items(self, items):
        return

    @abstractmethod
    def select_items(self):
        return

    @abstractmethod
    def update_items(items):
        return

我想将ItemTable类导入我的c++代码。最初我想使用boost.python，但由于缺乏导入示例（虽然有很多导出示例）但我决定坚持基本方法。

我的main.cpp文件看起来像这样

#include <cmath>
#include <boost/python.hpp>
#include <list>
#include <iostream>
using namespace boost::python;

class Item {
private:
    std::string item_id;
    std::string name;
    std::string description;
    friend class ItemTableWrapper;
};

class DbTableCoreWrapper {
public:
    virtual void create_table() = 0;
    virtual void drop_table() = 0;
    virtual void insert_items() = 0;
    virtual void select_items() = 0;
    virtual void update_items() = 0;
    virtual ~DbTableCoreWrapper() {
    }
};

class ItemTableWrapper: public DbTableCoreWrapper {
public:
    ItemTableWrapper() {
        Py_Initialize();

        script_name = PyString_FromString("item_table.py");
        pModule = PyImport_Import(script_name);
        PyErr_Print();
        pDict = PyModule_GetDict(pModule);
        pClass = PyDict_GetItemString(pDict, "ItemTable");

        if (PyCallable_Check(pClass)) {
            python_class_instance = PyObject_CallObject(pClass, NULL);
        }

    }
    ~ItemTableWrapper() {
        Py_DECREF(pModule);
        Py_DECREF(script_name);
        Py_DECREF(pDict);
        Py_DECREF(pClass);
        Py_DECREF(python_class_instance);

        Py_Finalize();
    }
private:
    PyObject *script_name;
    PyObject *pModule;
    PyObject *pDict;
    PyObject *pClass;
    PyObject *python_class_instance;
public:
    virtual void create_table() {
        PyObject_CallMethod(python_class_instance, "create_table", NULL);
    }
    virtual void drop_table() {
        PyObject_CallMethod(python_class_instance, "drop_table", NULL);
    }
    virtual void insert_items() {
        // clean for now
    }
    virtual void select_items() {
        PyObject* result = PyObject_CallMethod(python_class_instance,
                "select_items", NULL);
        if (result != NULL) {
            printf("Not empty select!");
        } else {
            PyErr_Print();
            printf("Empty select!");
        }
    }
    virtual void update_items() {
        // empty
    }
};

int main() {
    ItemTableWrapper *itw = new ItemTableWrapper();
    itw->select_items();

    delete itw;
    return 0;
}

但是当我尝试运行应用程序时，我得到了带有application stopped working的消息窗口和控制台中的消息

Program received signal SIGSEGV, Segmentation fault.
0x000000001e0c45d9 in python27!PyModule_GetDict () from C:\WINDOWS\system32\python27.dll

pDict = PyModule_GetDict(pModule);行失败。但我发现奇怪的是script_name看起来像这样

Name : script_name
    Details:0x20b1f30
    Default:0x20b1f30
    Decimal:34283312
    Hex:0x20b1f30
    Binary:10000010110001111100110000
    Octal:0202617460

而pModule看起来像这样

Name : pModule
    Details:0x0
    Default:0x0
    Decimal:0
    Hex:0x0
    Binary:0
    Octal:0

这意味着它没有加载模块。

有什么问题？此外，我的db_layer_core.py和item_table.py与application exe位于同一文件夹中。

应用程序运行期间出错

0 个答案: