PythonQt.h

#ifndef _PYTHONQT_H
#define _PYTHONQT_H

/*
 *
 *  Copyright (C) 2010 MeVis Medical Solutions AG All Rights Reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  Further, this software is distributed without any warranty that it is
 *  free of the rightful claim of any third person regarding infringement
 *  or the like.  Any license provided herein, whether implied or
 *  otherwise, applies only to this software file.  Patent licenses, if
 *  any, provided herein do not apply to combinations of this program with
 *  other software, or any other product whatsoever.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Contact information: MeVis Medical Solutions AG, Universitaetsallee 29,
 *  28359 Bremen, Germany or:
 *
 *  http://www.mevis.de
 *
 */

//----------------------------------------------------------------------------------
/*!
// \file    PythonQt.h
// \author  Florian Link
// \author  Last changed by $Author: florian $
// \date    2006-05
*/
//----------------------------------------------------------------------------------

#include "PythonQtPythonInclude.h"
#include "PythonQtUtils.h"
#include "PythonQtSystem.h"
#include "PythonQtInstanceWrapper.h"
#include "PythonQtClassWrapper.h"
#include "PythonQtSlot.h"
#include "PythonQtObjectPtr.h"
#include "PythonQtStdIn.h"
#include "PythonQtThreadSupport.h"
#include <QObject>
#include <QVariant>
#include <QList>
#include <QHash>
#include <QByteArray>
#include <QStringList>
#include <QtDebug>
#include <iostream>


class PythonQtClassInfo;
class PythonQtPrivate;
class PythonQtMethodInfo;
class PythonQtSignalReceiver;
class PythonQtImportFileInterface;
class PythonQtCppWrapperFactory;
class PythonQtForeignWrapperFactory;
class PythonQtQFileImporter;

typedef void  PythonQtVoidPtrCB(void* object);
typedef void  PythonQtQObjectWrappedCB(QObject* object);
typedef void  PythonQtQObjectNoLongerWrappedCB(QObject* object);
typedef void* PythonQtPolymorphicHandlerCB(const void *ptr, const char **class_name);
typedef QString PythonQtQObjectMissingAttributeCB(QObject* object, const QString& attribute);

typedef void PythonQtShellSetInstanceWrapperCB(void* object, PythonQtInstanceWrapper* wrapper);

template<class T> void PythonQtSetInstanceWrapperOnShell(void* object, PythonQtInstanceWrapper* wrapper) {
  (reinterpret_cast<T*>(object))->_wrapper = wrapper;
}

//! Helper template that allows to pass the ownership of a C++ instance between C++ and Python
//! (it is used as a slot return type or parameter type so that it can be detected by the PythonQt
//!  slot calling code).
template<class T>
class PythonQtPassOwnershipToCPP
{
  public:
    //! Allow conversion from T to PythonQtPassOwnershipToCPP<T>
    PythonQtPassOwnershipToCPP(const T& t):_t(t) {}
    //! Allow conversion from PythonQtPassOwnershipToCPP<T> to T
    operator T() const { return _t; }

    //! Stored value. This is important so that it has the same memory layout
    //! as a pointer if T is a pointer type (which is the typical use case for this class).
    T _t;
};

//! Helper template that allows to pass the ownership of a C++ instance between C++ and Python
//! (it is used as a slot return type or parameter type so that it can be detected by the PythonQt
//!  slot calling code).
template<class T>
class PythonQtPassOwnershipToPython
{
public:
  //! Allow conversion from T to PythonQtPassOwnershipToPython<T>
  PythonQtPassOwnershipToPython(const T& t):_t(t) {}
  //! Allow conversion from PythonQtPassOwnershipToPython<T> to T
  operator T() const { return _t; }

  //! Stored value. This is important so that it has the same memory layout
  //! as a pointer if T is a pointer type (which is the typical use case for this class).
  T _t;
};

//! Helper template that allows to pass the ownership of a C++ instance between C++ and Python
//! (it is used as a slot return type or parameter type so that it can be detected by the PythonQt
//!  slot calling code).
template<class T>
class PythonQtNewOwnerOfThis
{
public:
  //! Allow conversion from T to PythonQtNewOwnerOfThis<T>
  PythonQtNewOwnerOfThis(const T& t):_t(t) {}
  //! Allow conversion from PythonQtNewOwnerOfThis<T> to T
  operator T() const { return _t; }

  //! Stored value. This is important so that it has the same memory layout
  //! as a pointer if T is a pointer type (which is the typical use case for this class).
  T _t;
};


//! returns the offset that needs to be added to upcast an object of type T1 to T2
template<class T1, class T2> int PythonQtUpcastingOffset() {
  return ((reinterpret_cast<char*>(static_cast<T2*>(reinterpret_cast<T1*>(0x100))))
          - (reinterpret_cast<char*>(reinterpret_cast<T1*>(0x100))));
}

//! callback to create a QObject lazily
typedef QObject* PythonQtQObjectCreatorFunctionCB();

//! helper template to create a derived QObject class
template<class T> QObject* PythonQtCreateObject() { return new T(); }

//! Helper define to convert from QString to Python C-API
#ifdef PY3K
#define QStringToPythonConstCharPointer(arg) ((arg).toUtf8().constData())
#define QStringToPythonCharPointer(arg) ((arg).toUtf8().data())
#define QStringToPythonEncoding(arg) ((arg).toUtf8())
#else
#define QStringToPythonConstCharPointer(arg) ((arg).toLatin1().constData())
#define QStringToPythonCharPointer(arg) ((arg).toLatin1().data())
#define QStringToPythonEncoding(arg) ((arg).toLatin1())
#endif

//! The main interface to the Python Qt binding, realized as a singleton
/*!
 Use PythonQt::init() to initialize the singleton and PythonQt::self() to access it.
 While there can be only one PythonQt instance, you can have any number of Python context to do scripting in.
 One possibility is to use createModuleFromFile(), createModuleFromScript() or createUniqueModule() to get a context
 that is separated from the other contexts. Alternatively you can use Python dicts as contexts for script evaluation,
 but you will need to populate the dict with the __builtins__ instance to have all Pythons available when running
 code in the scope of a dict.
 */
class PYTHONQT_EXPORT PythonQt : public QObject {

  Q_OBJECT

public:

  //! flags that can be passed to PythonQt::init()
  enum InitFlags {
    RedirectStdOut = 1,   //!<< sets if the std out/err is redirected to pythonStdOut() and pythonStdErr() signals
    IgnoreSiteModule = 2, //!<< sets if Python should ignore the site module
    ExternalHelp = 4,     //!<< sets if help() calls on PythonQt modules are forwarded to the pythonHelpRequest() signal
    PythonAlreadyInitialized = 8 //!<< sets that PythonQt should not can PyInitialize, since it is already done
  };

  //! flags that tell PythonQt which operators to expect on the registered type
  enum TypeSlots {
    Type_Add = 1,
    Type_Subtract = 1 << 1,
    Type_Multiply = 1 << 2,
    Type_Divide = 1 << 3,
    Type_Mod = 1 << 4,
    Type_And = 1 << 5,
    Type_Or = 1 << 6,
    Type_Xor = 1 << 7,
    Type_LShift = 1 << 8,
    Type_RShift = 1 << 9,

    Type_InplaceAdd = 1 << 10,
    Type_InplaceSubtract = 1 << 11,
    Type_InplaceMultiply = 1 << 12,
    Type_InplaceDivide = 1 << 13,
    Type_InplaceMod = 1 << 14,
    Type_InplaceAnd = 1 << 15,
    Type_InplaceOr = 1 << 16,
    Type_InplaceXor = 1 << 17,
    Type_InplaceLShift = 1 << 18,
    Type_InplaceRShift = 1 << 19,

    Type_Length = 1 << 20,
    Type_MappingSetItem = 1 << 21,
    Type_MappingGetItem = 1 << 22,

    Type_EnterExit = 1 << 23,

    Type_Invert = 1 << 29,
    Type_RichCompare = 1 << 30,
    Type_NonZero     = 1 << 31,

  };

  //! enum for profiling callback
  enum ProfilingCallbackState {
    Enter = 1,
    Leave = 2
  };

  //! callback for profiling. className and methodName are only passed when state == Enter, otherwise
  //! they are NULL.
  typedef void ProfilingCB(ProfilingCallbackState state, const char* className, const char* methodName, PyObject* args);

  //---------------------------------------------------------------------------
  //! \name Singleton Initialization
  //@{

  //! initialize the python qt binding (flags are a or combination of PythonQt::InitFlags), if \c pythonQtModuleName is given
  //! it defines the name of the python module that PythonQt will add, otherwise "PythonQt" is used.
  //! This can be used to e.g. pass in PySide or PyQt4 to make it more compatible.
  static void init(int flags = IgnoreSiteModule | RedirectStdOut, const QByteArray& pythonQtModuleName = QByteArray());

  //! cleanup of the singleton
  static void cleanup();

  //! get the singleton instance
  static PythonQt* self();

  //@}

  //! defines the object types for introspection
  enum ObjectType {
    Class,
    Function,
    Variable,
    Module,
    Anything,
    CallOverloads
  };


  //---------------------------------------------------------------------------
  //! \name Standard input handling
  //@{

  //! Overwrite default handling of stdin using a custom callback. It internally backup
  //! the original 'sys.stdin' into 'sys.pythonqt_original_stdin'
  void setRedirectStdInCallback(PythonQtInputChangedCB* callback, void * callbackData = nullptr);

  //! Enable or disable stdin custom callback. It resets 'sys.stdin' using either 'sys.pythonqt_stdin'
  //! or 'sys.pythonqt_original_stdin'
  void setRedirectStdInCallbackEnabled(bool enabled);

  //@}

  //---------------------------------------------------------------------------
  //! \name Standard output handling
  //@{

  //! return \a true if std out/err redirection is enabled.
  bool redirectStdOutCallbackEnabled() const;

  //! enable or disable std out/err redirection to pythonStdOut() and pythonStdErr() signals.
  void setRedirectStdOutCallbackEnabled(bool enabled);

  //@}

  //---------------------------------------------------------------------------
  //! \name Modules
  //@{

  //! get the __main__ module of python
  PythonQtObjectPtr getMainModule();

  //! import the given module and return a reference to it (useful to import e.g. "sys" and call something on it)
  //! If a module is already imported, this returns the already imported module.
  PythonQtObjectPtr importModule(const QString& name);

  //! creates the new module \c name and evaluates the given file in the context of that module
  //! If the \c script is empty, the module contains no initial code. You can use evalScript/evalCode to add code
  //! to a module later on.
  //! The user needs to make sure that the \c name is unique in the python module dictionary.
  PythonQtObjectPtr createModuleFromFile(const QString& name, const QString& filename);

  //! creates the new module \c name and evaluates the given script in the context of that module.
  //! If the \c script is empty, the module contains no initial code. You can use evalScript/evalCode to add code
  //! to a module later on.
  //! The user needs to make sure that the \c name is unique in the python module dictionary.
  PythonQtObjectPtr createModuleFromScript(const QString& name, const QString& script = QString());

  //! create a uniquely named module, you can use evalFile or evalScript to populate the module with
  //! script code
  PythonQtObjectPtr createUniqueModule();

  //@}

  //---------------------------------------------------------------------------
  //! \name Importing/Paths
  //@{

  //! overwrite the python sys path (call this directly after PythonQt::init() if you want to change the std python sys path)
  void overwriteSysPath(const QStringList& paths);

  //! prepend a path to sys.path to allow importing from it
  void addSysPath(const QString& path);

  //! sets the __path__ list of a module to the given list (important for local imports)
  void setModuleImportPath(PyObject* module, const QStringList& paths);

  //@}

  //---------------------------------------------------------------------------
  //! \name Registering Classes
  //@{

  //! registers a QObject derived class to PythonQt (this is implicitly called by addObject as well)
  /* Since Qt4 does not offer a way to detect if a given classname is derived from QObject and thus has a QMetaObject,
   you MUST register all your QObject derived classes here when you want them to be detected in signal and slot calls */
  void registerClass(const QMetaObject* metaobject, const char* package = nullptr, PythonQtQObjectCreatorFunctionCB* wrapperCreator = nullptr, PythonQtShellSetInstanceWrapperCB* shell = nullptr);

  //! add a wrapper object for the given QMetaType typeName, also does an addClassDecorators() to add constructors for variants
  //! (ownership of wrapper is passed to PythonQt)
  /*! Make sure that you have done a qRegisterMetaType first, if typeName is a user type!

   This will add a wrapper object that is used to make calls to the given classname \c typeName.
   All slots that take a pointer to typeName as the first argument will be callable from Python on
   a variant object that contains such a type.
   */
  void registerCPPClass(const char* typeName, const char* parentTypeName = nullptr, const char* package = nullptr, PythonQtQObjectCreatorFunctionCB* wrapperCreator = nullptr, PythonQtShellSetInstanceWrapperCB* shell = nullptr);

  //! as an alternative to registerClass, you can tell PythonQt the names of QObject derived classes
  //! and it will register the classes when it first sees a pointer to such a derived class
  void registerQObjectClassNames(const QStringList& names);

  //! add a parent class relation to the \c given typeName, the upcastingOffset is needed for multiple inheritance
  //! and can be calculated using PythonQtUpcastingOffset<type,parentType>(), which also verifies that
  //! type is really derived from parentType.
  //! Returns false if the typeName was not yet registered.
  bool addParentClass(const char* typeName, const char* parentTypeName, int upcastingOffset=0);

  //! add a handler for polymorphic downcasting
  void addPolymorphicHandler(const char* typeName, PythonQtPolymorphicHandlerCB* cb);

  //@}

  //---------------------------------------------------------------------------
  //! \name Script Parsing and Evaluation
  //@{

  //! parses the given file (using PythonQt's own import mechanism) and returns the python code object, this can then be used to call evalCode()
  PythonQtObjectPtr parseFile(const QString& filename);

  //! Parses the given file and returns the python code object, this can then be used to call evalCode()
  //! It uses Python's importlib machinery to load the file's code and supports source and sourceless loading
  //! and generation of cache files.
  //! This method is PY3K only!
  PythonQtObjectPtr parseFileWithPythonLoaders(const QString& filename);

  //! evaluates the given code and returns the result value (use Py_Compile etc. to create pycode from string)
  //! If pycode is NULL, a python error is printed.
  QVariant evalCode(PyObject* object, PyObject* pycode);

  //! evaluates the given script code and returns the result value
  QVariant evalScript(PyObject* object, const QString& script, int start = Py_file_input);

  //! evaluates the given script code in context of given globals and locals and returns the result value
  QVariant evalScript(const QString& script, PyObject* globals, PyObject* locals, int start);

  //! evaluates the given script code from file
  void evalFile(PyObject* object, const QString& filename);

  //@}

  //---------------------------------------------------------------------------
  //! \name Signal Handlers
  //@{

  //! add a signal handler to the given \c signal of \c obj  and connect it to a callable \c objectname in module
  bool addSignalHandler(QObject* obj, const char* signal, PyObject* module, const QString& objectname);

  //! remove a signal handler from the given \c signal of \c obj
  bool removeSignalHandler(QObject* obj, const char* signal, PyObject* module, const QString& objectname);

  //! add a signal handler to the given \c signal of \c obj  and connect it to a callable \c receiver
  bool addSignalHandler(QObject* obj, const char* signal, PyObject* receiver);

  //! remove a signal handler from the given \c signal of \c obj
  bool removeSignalHandler(QObject* obj, const char* signal, PyObject* receiver);

  //! globally removes all signal handlers (connections between QObjects and Python).
  void removeSignalHandlers();

  //@}

  //---------------------------------------------------------------------------
  //! \name Variable access
  //@{

  //! add the given \c qObject to the python \c object as a variable with \c name (it can be removed via clearVariable)
  void addObject(PyObject* object, const QString& name, QObject* qObject);

  //! add the given variable to the object
  void addVariable(PyObject* object, const QString& name, const QVariant& v);

  //! remove the given variable
  void removeVariable(PyObject* module, const QString& name);

  //! get the variable with the \c name of the \c object, returns an invalid QVariant on error
  QVariant getVariable(PyObject* object, const QString& name);

  //! get the variable with the \c name of the \c object as QVariant of type PythonQtObjectPtr, returns an invalid QVariant on error
  QVariant getNativeVariable(PyObject* object, const QString& name);

  //! read vars etc. in scope of an \c object, optional looking inside of an object \c objectname
  QStringList introspection(PyObject* object, const QString& objectname, ObjectType type);
  //! read vars etc. in scope of the given \c object
  QStringList introspectObject(PyObject* object, ObjectType type);
  //! read vars etc. in scope of the type object called \c typename. First the typename
  //! of the form module.type is split into module and type. Then the module is looked up
  //! in sys.modules. If the module or type is not found there, then the type is looked up in
  //! the __builtin__ module.
  QStringList introspectType(const QString& typeName, ObjectType type);

  //! returns the found callable object or NULL
  //! @return new reference
  PythonQtObjectPtr lookupCallable(PyObject* object, const QString& name);

  //! returns the return type of the method of a wrapped c++ object referenced by \c objectname
  QString getReturnTypeOfWrappedMethod(PyObject* module, const QString& objectname);
  //! returns the return type of the method \c methodName of a wrapped c++ type referenced by \c typeName
  QString getReturnTypeOfWrappedMethod(const QString& typeName, const QString& methodName);
  //@}

  //---------------------------------------------------------------------------
  //! \name Calling Python Objects
  //@{

  //! call the given python \c callable in the scope of object, returns the result converted to a QVariant
  QVariant call(PyObject* object, const QString& callable, const QVariantList& args = QVariantList(), const QVariantMap& kwargs = QVariantMap());

  //! call the given python object, returns the result converted to a QVariant
  QVariant call(PyObject* callable, const QVariantList& args = QVariantList(), const QVariantMap& kwargs = QVariantMap());

  //! call the given python object, returns the result as new PyObject
  PyObject* callAndReturnPyObject(PyObject* callable, const QVariantList& args = QVariantList(), const QVariantMap& kwargs = QVariantMap());

  //@}

  //---------------------------------------------------------------------------
  //! \name Decorations, Constructors, Wrappers...
  //@{

  //! add an object whose slots will be used as decorator slots for
  //! other QObjects or CPP classes. The slots need to follow the
  //! convention that the first argument is a pointer to the wrapped object.
  //! (ownership is passed to PythonQt)
  /*!
  Example:

  A slot with the signature

  \code
  bool doSomething(QWidget* w, int a)
  \endcode

  will extend QWidget instances (and derived classes) with a "bool doSomething(int a)" slot
  that will be called with the concrete instance as first argument.
  So in Python you can now e.g. call

  \code
  someWidget.doSomething(12)
  \endcode

  without QWidget really having this method. This allows to easily make normal methods
  of Qt classes callable by forwarding them with such decorator slots
  or to make CPP classes (which are not derived from QObject) callable from Python.
  */
  void addInstanceDecorators(QObject* o);

  //! add an object whose slots will be used as decorator slots for
  //! class objects (ownership is passed to PythonQt)
  /*!
  The slots need to follow the following convention:
  - SomeClass* new_SomeClass(...)
  - QVariant new_SomeClass(...)
  - void delete_SomeClass(SomeClass*)
  - ... static_SomeClass_someName(...)

  This will add:
  - a constructor
  - a constructor which generates a QVariant
  - a destructor (only useful for CPP objects)
  - a static decorator slot which will be available on the MetaObject (visible in PythonQt module)

  */
  void addClassDecorators(QObject* o);

  //! this will add the object both as class and instance decorator (ownership is passed to PythonQt)
  void addDecorators(QObject* o);

  //! add the given factory to PythonQt (ownership stays with caller)
  void addWrapperFactory(PythonQtCppWrapperFactory* factory);

  //! add the given factory to PythonQt (ownership stays with caller)
  void addWrapperFactory(PythonQtForeignWrapperFactory* factory);

  //! remove the wrapper factory
  void removeWrapperFactory(PythonQtCppWrapperFactory* factory);

  //! remove the wrapper factory
  void removeWrapperFactory(PythonQtForeignWrapperFactory* factory);

  //@}

  //---------------------------------------------------------------------------
  //! \name Custom Importer
  //@{

  //! replace the internal import implementation and use the supplied interface to load files (both py and pyc files)
  //! (this method should be called directly after initialization of init() and before calling overwriteSysPath().
  //! On the first call to this method, it will install a generic PythonQt importer in Pythons "path_hooks".
  //! This is not reversible, so even setting setImporter(NULL) afterwards will
  //! keep the custom PythonQt importer with a QFile default import interface.
  //! Subsequent python import calls will make use of the passed importInterface
  //! which forwards all import calls to the given \c importInterface.
  //! Passing NULL will install a default QFile importer.
  //! (\c importInterface ownership stays with caller)
  void setImporter(PythonQtImportFileInterface* importInterface);

  //! this installs the default QFile importer (which effectively does a setImporter(NULL))
  //! (without calling setImporter or installDefaultImporter at least once, the default python import
  //! mechanism is in place)
  //! the default importer allows to import files from anywhere QFile can read from,
  //! including the Qt resource system using ":". Keep in mind that you need to extend
  //! "sys.path" with ":" to be able to import from the Qt resources.
  void installDefaultImporter() { setImporter(nullptr); }

  //! set paths that the importer should ignore
  void setImporterIgnorePaths(const QStringList& paths);

  //! get paths that the importer should ignore
  const QStringList& getImporterIgnorePaths();

  //! get access to the file importer (if set)
  static PythonQtImportFileInterface* importInterface();

  //@}

  //---------------------------------------------------------------------------
  //! \name Other Stuff
  //@{

  //! get access to internal data (should not be used on the public API, but is used by some C functions)
  static PythonQtPrivate* priv() { return _self ? _self->_p : nullptr; }

  //! clear all NotFound entries on all class infos, to ensure that
  //! newly loaded wrappers can add methods even when the object was wrapped by PythonQt before the wrapper was loaded
  void clearNotFoundCachedMembers();

  //! handle a python error, call this when a python function fails. If no error occurred, it returns false.
  //! The error is currently just output to the python stderr, future version might implement better trace printing
  bool handleError(bool printStack = true);

  //! return \a true if \a handleError() has been called and an error occurred.
  bool hadError()const;

  //! reset error flag. After calling this, hadError() will return false.
  //! \sa hadError()
  void clearError();

  //! if set to true, the systemExitExceptionRaised signal will be emitted if exception SystemExit is caught
  //! \sa handleError()
  void setSystemExitExceptionHandlerEnabled(bool value);

  //! return \a true if SystemExit exception is handled by PythonQt
  //! \sa setSystemExitExceptionHandlerEnabled()
  bool systemExitExceptionHandlerEnabled() const;

  //! set a callback that is called when a QObject with parent == NULL is wrapped by PythonQt
  void setQObjectWrappedCallback(PythonQtQObjectWrappedCB* cb);
  //! set a callback that is called when a QObject with parent == NULL is no longer wrapped by PythonQt
  void setQObjectNoLongerWrappedCallback(PythonQtQObjectNoLongerWrappedCB* cb);

  //! call the callback if it is set
  static void qObjectNoLongerWrappedCB(QObject* o);

  //! set a callback that is called when a QObject does not have a specific attribute.
  void setQObjectMissingAttributeCallback(PythonQtQObjectMissingAttributeCB* cb);

  //! call the callback if it is set
  static QString qObjectMissingAttributeCallback(QObject* o, const QString& attribute);

  //! called by internal help methods
  PyObject* helpCalled(PythonQtClassInfo* info);

  //! returns the found object or NULL
  //! @return new reference
  PythonQtObjectPtr lookupObject(PyObject* module, const QString& name);

  //! sets a callback that is called before and after function calls for profiling
  void setProfilingCallback(ProfilingCB* cb);

  //! Enable GIL and thread state handling (turned off by default).
  //! If you want to use Python threading, you have to call this
  //! with true early in your main thread, before you launch
  //! any threads in Python. It can be called before or after
  //! PythonQt::init().
  static void setEnableThreadSupport(bool flag);

  //@}

Q_SIGNALS:
  //! emitted when python outputs something to stdout (and redirection is turned on)
  void pythonStdOut(const QString& str);
  //! emitted when python outputs something to stderr (and redirection is turned on)
  void pythonStdErr(const QString& str);

  //! emitted when help() is called on a PythonQt object and \c ExternalHelp is enabled
  void pythonHelpRequest(const QByteArray& cppClassName);

  //! emitted when both custom SystemExit exception handler is enabled and a SystemExit
  //! exception is raised.
  //! \sa setSystemExitExceptionHandlerEnabled(bool)
  void systemExitExceptionRaised(int exitCode);

private:
  void initPythonQtModule(bool redirectStdOut, const QByteArray& pythonQtModuleName);

  QString getReturnTypeOfWrappedMethodHelper(const PythonQtObjectPtr& variableObject, const QString& methodName, const QString& context);

  PyObject* getObjectByType(const QString& typeName);

  //! callback for stdout redirection, emits pythonStdOut signal
  static void stdOutRedirectCB(const QString& str);
  //! callback for stderr redirection, emits pythonStdErr signal
  static void stdErrRedirectCB(const QString& str);

  //! get (and create if not available) the signal receiver of that QObject, signal receiver is made child of the passed \c obj
  PythonQtSignalReceiver* getSignalReceiver(QObject* obj);

  PythonQt(int flags, const QByteArray& pythonQtModuleName);
  ~PythonQt() override;
  static PythonQt* _self;
  static int _uniqueModuleCount;

  PythonQtPrivate* _p;

};

class PythonQtDebugAPI;
class PythonQtConfigAPI;

//! internal PythonQt details
class PYTHONQT_EXPORT PythonQtPrivate : public QObject {

  Q_OBJECT

public:
  PythonQtPrivate();
  ~PythonQtPrivate() override;

  enum DecoratorTypes {
    StaticDecorator = 1,
    ConstructorDecorator = 2,
    DestructorDecorator = 4,
    InstanceDecorator = 8,
    AllDecorators = 0xffff
  };

  //! Set a callable that is used as the argument for the add_done_callback for the Task
  //! created by checkAndRunCoroutine
  void setTaskDoneCallback(const PythonQtObjectPtr& callable);

  //! Runs the given coroutine (via asyncio), returns a scheduled task if it object is a coroutine.
  PythonQtObjectPtr checkAndRunCoroutine(const PythonQtObjectPtr& object);

  //! Creates a new asyncio.Future object
  PythonQtObjectPtr createAsyncioFuture();

  //! get the suffixes that are used for shared libraries
  const QStringList& sharedLibrarySuffixes() { return _sharedLibrarySuffixes; }

  //! returns if the id is the id for PythonQtObjectPtr
  bool isPythonQtObjectPtrMetaId(int id) { return _PythonQtObjectPtr_metaId == id; }
  //! returns if the id is the id for PythonQtSafeObjectPtr
  bool isPythonQtSafeObjectPtrMetaId(int id) { return _PythonQtSafeObjectPtr_metaId == id; }
  //! returns if the id is either PythonQtObjectPtr or PythonQtSafeObjectPtr
  bool isPythonQtAnyObjectPtrMetaId(int id) { return _PythonQtObjectPtr_metaId == id || _PythonQtSafeObjectPtr_metaId == id; }

  //! add the wrapper pointer (for reuse if the same obj appears while wrapper still exists)
  void addWrapperPointer(void* obj, PythonQtInstanceWrapper* wrapper);
  //! remove the wrapper ptr again
  void removeWrapperPointer(void* obj);

  //! called by destructor of shells to allow invalidation of the Python wrapper
  void shellClassDeleted(void* shellClass);

  //! try to unwrap the given object to a C++ pointer using the foreign wrapper factories
  void* unwrapForeignWrapper(const QByteArray& classname, PyObject* obj);

  //! add parent class relation
  bool addParentClass(const char* typeName, const char* parentTypeName, int upcastingOffset);

  //! add a handler for polymorphic downcasting
  void addPolymorphicHandler(const char* typeName, PythonQtPolymorphicHandlerCB* cb);

  //! lookup existing classinfo and return new if not yet present
  PythonQtClassInfo* lookupClassInfoAndCreateIfNotPresent(const char* typeName);

  //! called when a signal emitting QObject is destroyed to remove the signal handler from the hash map
  void removeSignalEmitter(QObject* obj);

  //! wrap the given QObject into a Python object (or return existing wrapper!)
  PyObject* wrapQObject(QObject* obj);

  //! wrap the given ptr into a Python object (or return existing wrapper!) if there is a known QObject of that name or a known wrapper in the factory.
  //! If passOwnership == true, the ownership is passed to PythonQt, so the object will be deleted by PythonQt when the Python wrapper
  //! goes away.
  PyObject* wrapPtr(void* ptr, const QByteArray& name, bool passOwnership = false);

  //! create a read-only buffer object from the given memory
  static PyObject* wrapMemoryAsBuffer(const void* data, Py_ssize_t size);

  //! create a read-write buffer object from the given memory
  static PyObject* wrapMemoryAsBuffer(void* data, Py_ssize_t size);

  //! registers a QObject derived class to PythonQt (this is implicitly called by addObject as well)
  /* Since Qt4 does not offer a way to detect if a given classname is derived from QObject and thus has a QMetaObject,
     you MUST register all your QObject derived classes here when you want them to be detected in signal and slot calls */
  void registerClass(const QMetaObject* metaobject, const char* package = nullptr, PythonQtQObjectCreatorFunctionCB* wrapperCreator = nullptr, PythonQtShellSetInstanceWrapperCB* shell = nullptr, PyObject* module = nullptr, int typeSlots = 0);

  //! add a wrapper object for the given QMetaType typeName, also does an addClassDecorators() to add constructors for variants
  //! (ownership of wrapper is passed to PythonQt)
  /*! Make sure that you have done a qRegisterMetaType first, if typeName is a user type!

   This will add a wrapper object that is used to make calls to the given classname \c typeName.
   All slots that take a pointer to typeName as the first argument will be callable from Python on
   a variant object that contains such a type.
   */
  void registerCPPClass(const char* typeName, const char* parentTypeName = nullptr, const char* package = nullptr, PythonQtQObjectCreatorFunctionCB* wrapperCreator = nullptr, PythonQtShellSetInstanceWrapperCB* shell = nullptr, PyObject* module = nullptr, int typeSlots = 0);

  //! Same as above, but all enums of the created wrapper will also be added to the given package and to the "Qt" package
  void registerGlobalNamespace(const char* typeName, const char* package, PythonQtQObjectCreatorFunctionCB* wrapperCreator, const QMetaObject& metaObject, PyObject* module = nullptr);

  //! as an alternative to registerClass, you can tell PythonQt the names of QObject derived classes
  //! and it will register the classes when it first sees a pointer to such a derived class
  void registerQObjectClassNames(const QStringList& names);

  //! add a decorator object
  void addDecorators(QObject* o, int decoTypes);

  //! helper method that creates a PythonQtClassWrapper object  (returns a new reference)
  PythonQtClassWrapper* createNewPythonQtClassWrapper(PythonQtClassInfo* info, PyObject* module, const QByteArray& pythonClassName);

  //! create a new instance of the given enum type with given value (returns a new reference)
  static PyObject*  createEnumValueInstance(PyObject* enumType, unsigned int enumValue);

  //! helper that creates a new int derived class that represents the enum of the given name  (returns a new reference)
  static PyObject* createNewPythonQtEnumWrapper(const char* enumName, PyObject* parentObject);

  //! helper method that creates a PythonQtInstanceWrapper object and registers it in the object map
  PythonQtInstanceWrapper* createNewPythonQtInstanceWrapper(QObject* obj, PythonQtClassInfo* info, void* wrappedPtr = nullptr);

  //! get the class info for a meta object (if available)
  PythonQtClassInfo* getClassInfo(const QMetaObject* meta);

  //! get the class info for a meta object (if available)
  PythonQtClassInfo* getClassInfo(const QByteArray& className);

  //! register a class name that causes lazy loading of the moduleToImport when
  //! PythonQt encounters the type
  void registerLazyClass(const QByteArray& name, const QByteArray& moduleToImport);

  //! creates the new module from the given pycode
  PythonQtObjectPtr createModule(const QString& name, PyObject* pycode);

  //! get the current class info (for the next PythonQtClassWrapper that is created) and reset it to NULL again
  PythonQtClassInfo* currentClassInfoForClassWrapperCreation();

  //! the dummy tuple (which is empty and may be used to detected that a wrapper is called from internal wrapper creation
  static PyObject* dummyTuple();

  //! called by virtual overloads when a python return value can not be converted to the required Qt type
  void handleVirtualOverloadReturnError(const char* signature, const PythonQtMethodInfo* methodInfo, PyObject* result);

  //! get access to the PythonQt module
  PythonQtObjectPtr pythonQtModule() const { return _pythonQtModule; }

  //! returns the profiling callback, which may be NULL
  PythonQt::ProfilingCB* profilingCB() const { return _profilingCB; }

  //! determines the signature of the given callable object (similar as pydoc)
  QString getSignature(PyObject* object);

  //! returns true if the object is a method descriptor (same as inspect.ismethoddescriptor() in inspect.py)
  bool isMethodDescriptor(PyObject* object) const;

  //! get the dynamic meta object for the given wrapper. It will contain the signals/slots that have been added in Python
  const QMetaObject* getDynamicMetaObject(PythonQtInstanceWrapper* wrapper, const QMetaObject* prototypeMetaObject);

  //! recursively creates the dynamic meta object chain down to the Qt class wrapper.
  const QMetaObject* setupDynamicMetaObjectChain(PythonQtClassWrapper* type, const QMetaObject* prototypeMetaObject);

  //! builds and returns the dynamic meta object for the given type, derived from prototypeMetaObject.
  const QMetaObject* buildDynamicMetaObject(PythonQtClassWrapper* type, const QMetaObject* prototypeMetaObject);

  //! redirected from shell classes, tries to call the given meta call on the Python wrapper.
  int handleMetaCall(QObject* object, PythonQtInstanceWrapper* wrapper, QMetaObject::Call call, int id, void** args);

  //! calls the given method on Python function with same name.
  void callMethodInPython(QMetaMethod &method, PythonQtInstanceWrapper* wrapper, void** args);

private:
  //! Setup the shared library suffixes by getting them from the "imp" module.
  void setupSharedLibrarySuffixes();

  //! create a new pythonqt class wrapper and place it in the pythonqt module
  void createPythonQtClassWrapper(PythonQtClassInfo* info, const char* package, PyObject* module = nullptr);

  //! get/create new package module (the returned object is a borrowed reference)
  PyObject* packageByName(const char* name);

  //! get the wrapper for a given pointer (and remove a wrapper of an already destroyed qobject)
  PythonQtInstanceWrapper* findWrapperAndRemoveUnused(void* obj);

  //! stores pointer to PyObject mapping of wrapped QObjects AND C++ objects
  QHash<void* , PythonQtInstanceWrapper *> _wrappedObjects;

  //! stores the meta info of known Qt classes
  QHash<QByteArray, PythonQtClassInfo *>   _knownClassInfos;

  //! names of qobject derived classes that can be casted to qobject savely
  QHash<QByteArray, bool> _knownQObjectClassNames;

  //! lazy classes that cause PythonQt to trigger an import if they are encountered.
  QHash<QByteArray, QByteArray> _knownLazyClasses;

  //! stores signal receivers for QObjects
  QHash<QObject* , PythonQtSignalReceiver *> _signalReceivers;

  //! the PythonQt python module
  PythonQtObjectPtr _pythonQtModule;

  //! the name of the PythonQt python module
  QByteArray _pythonQtModuleName;

  //! the importer interface (if set)
  PythonQtImportFileInterface* _importInterface;

  //! the default importer
  PythonQtQFileImporter* _defaultImporter;

  PythonQtQObjectNoLongerWrappedCB* _noLongerWrappedCB;
  PythonQtQObjectWrappedCB* _wrappedCB;
  PythonQtQObjectMissingAttributeCB* _qObjectMissingAttribCB;

  QStringList _importIgnorePaths;
  QStringList _sharedLibrarySuffixes;

  PythonQtObjectPtr _pySourceFileLoader;
  PythonQtObjectPtr _pySourcelessFileLoader;
  PythonQtObjectPtr _pyEnsureFuture;
  PythonQtObjectPtr _pyFutureClass;

  PythonQtObjectPtr _pyTaskDoneCallback;

  //! the cpp object wrapper factories
  QList<PythonQtCppWrapperFactory*> _cppWrapperFactories;

  QList<PythonQtForeignWrapperFactory*> _foreignWrapperFactories;

  QHash<QByteArray, PyObject*> _packages;

  PythonQtClassInfo* _currentClassInfoForClassWrapperCreation;

  PythonQt::ProfilingCB* _profilingCB;

  PythonQtDebugAPI* _debugAPI;
  PythonQtConfigAPI* _configAPI;

  int _initFlags;
  int _PythonQtObjectPtr_metaId;
  int _PythonQtSafeObjectPtr_metaId;

  bool _hadError;
  bool _systemExitExceptionHandlerEnabled;

  friend class PythonQt;
};

#endif