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**
** Copyright (C) 2018 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt for Python.
**
** $QT_BEGIN_LICENSE:LGPL$
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** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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****************************************************************************/

#include "sbkenum.h"
#include "sbkstring.h"
#include "sbkconverter.h"
#include "basewrapper.h"
#include "sbkdbg.h"
#include "autodecref.h"
#include "sbkpython.h"

#include <string.h>
#include <cstring>
#include <list>

#define SBK_ENUM(ENUM) reinterpret_cast<SbkEnumObject*>(ENUM)

extern "C"
{

struct SbkEnumTypePrivate
{
    SbkConverter** converterPtr;
    SbkConverter* converter;
    const char* cppName;
};

struct SbkEnumType
{
    PepTypeObject type;
};

struct SbkEnumObject
{
    PyObject_HEAD
    long ob_value;
    PyObject* ob_name;
};

static PyObject* SbkEnumObject_repr(PyObject* self)
{
    const SbkEnumObject *enumObj = reinterpret_cast<SbkEnumObject *>(self);
    if (enumObj->ob_name)
        return Shiboken::String::fromFormat("%s.%s", PepType((Py_TYPE(self)))->tp_name, PyBytes_AS_STRING(enumObj->ob_name));
    else
        return Shiboken::String::fromFormat("%s(%ld)", PepType((Py_TYPE(self)))->tp_name, enumObj->ob_value);
}

static PyObject* SbkEnumObject_name(PyObject* self, void*)
{
    SbkEnumObject *enum_self = reinterpret_cast<SbkEnumObject *>(self);

    if (enum_self->ob_name == NULL)
        Py_RETURN_NONE;

    Py_INCREF(enum_self->ob_name);
    return enum_self->ob_name;
}

static PyObject* SbkEnum_tp_new(PyTypeObject *type, PyObject *args, PyObject *)
{
    long itemValue = 0;
    if (!PyArg_ParseTuple(args, "|l:__new__", &itemValue))
        return 0;

    SbkEnumObject* self = PyObject_New(SbkEnumObject, type);
    if (!self)
        return 0;
    self->ob_value = itemValue;
    PyObject* item = Shiboken::Enum::getEnumItemFromValue(type, itemValue);
    if (item) {
        self->ob_name = SbkEnumObject_name(item, 0);
        Py_XDECREF(item);
    } else {
        self->ob_name = 0;
    }
    return reinterpret_cast<PyObject*>(self);
}

/* Notes:
 *   On Py3k land we use long type when using integer numbers. However, on older
 *   versions of Python (version 2) we need to convert it to int type,
 *   respectively.
 *
 *   Thus calling PyInt_FromLong() will result in calling PyLong_FromLong in
 *   Py3k.
 */
static PyObject* enum_int(PyObject* v)
{
    return PyInt_FromLong(SBK_ENUM(v)->ob_value);
}

static long getNumberValue(PyObject* v)
{
    PyObject* number = PyNumber_Long(v);
    long result = PyLong_AsLong(number);
    Py_XDECREF(number);
    return result;
}

static PyObject* enum_and(PyObject* self, PyObject* b)
{
    if (!PyNumber_Check(b)) {
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(b);
    return PyInt_FromLong(valA & valB);
}

static PyObject* enum_or(PyObject* self, PyObject* b)
{
    if (!PyNumber_Check(b)) {
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(b);
    return PyInt_FromLong(valA | valB);
}

static PyObject* enum_xor(PyObject* self, PyObject* b)
{
    if (!PyNumber_Check(b)) {
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(b);
    return PyInt_FromLong(valA ^ valB);
}

static int enum_bool(PyObject* v)
{
    return (SBK_ENUM(v)->ob_value > 0);
}

static PyObject* enum_add(PyObject* self, PyObject* v)
{
    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(v);
    return PyInt_FromLong(valA + valB);
}

static PyObject* enum_subtract(PyObject* self, PyObject* v)
{
    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(v);
    return PyInt_FromLong(valA - valB);
}

static PyObject* enum_multiply(PyObject* self, PyObject* v)
{
    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(v);
    return PyInt_FromLong(valA * valB);
}

#ifndef IS_PY3K
static PyObject* enum_divide(PyObject* self, PyObject* v)
{
    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(v);
    return PyLong_FromLong(valA / valB);
}
#endif

static PyObject* enum_richcompare(PyObject* self, PyObject* other, int op)
{
    int result = 0;
    if (!PyNumber_Check(other)) {
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    long valA = SBK_ENUM(self)->ob_value;
    long valB = getNumberValue(other);

    switch (op) {
    case Py_EQ:
        result = (valA == valB);
        break;
    case Py_NE:
        result = (valA != valB);
        break;
    case Py_LE:
        result = (valA <= valB);
        break;
    case Py_GE:
        result = (valA >= valB);
        break;
    case Py_LT:
        result = (valA < valB);
        break;
    case Py_GT:
        result = (valA > valB);
        break;
    default:
        PyErr_BadArgument();
        return NULL;
    }
    if (result)
        Py_RETURN_TRUE;
    else
        Py_RETURN_FALSE;
}

static Py_hash_t enum_hash(PyObject* pyObj)
{
    Py_hash_t val = reinterpret_cast<SbkEnumObject*>(pyObj)->ob_value;
    if (val == -1)
        val = -2;
    return val;
}

static PyGetSetDef SbkEnumGetSetList[] = {
    {const_cast<char*>("name"), &SbkEnumObject_name, 0, 0, 0},
    {0, 0, 0, 0, 0} // Sentinel
};

static void SbkEnumTypeDealloc(PyObject* pyObj);
static PyObject* SbkEnumTypeTpNew(PyTypeObject* metatype, PyObject* args, PyObject* kwds);

static PyType_Slot SbkEnumType_Type_slots[] = {
    {Py_tp_dealloc, (void *)SbkEnumTypeDealloc},
    {Py_nb_add, (void *)enum_add},
    {Py_nb_subtract, (void *)enum_subtract},
    {Py_nb_multiply, (void *)enum_multiply},
#ifndef IS_PY3K
    {Py_nb_divide, (void *)enum_divide},
#endif
    {Py_nb_positive, (void *)enum_int},
#ifdef IS_PY3K
    {Py_nb_bool, (void *)enum_bool},
#else
    {Py_nb_nonzero, (void *)enum_bool},
    {Py_nb_long, (void *)enum_int},
#endif
    {Py_nb_and, (void *)enum_and},
    {Py_nb_xor, (void *)enum_xor},
    {Py_nb_or, (void *)enum_or},
    {Py_nb_int, (void *)enum_int},
    {Py_nb_index, (void *)enum_int},
    {Py_tp_base, (void *)&PyType_Type},
    {Py_tp_alloc, (void *)PyType_GenericAlloc},
    {Py_tp_new, (void *)SbkEnumTypeTpNew},
    {Py_tp_free, (void *)PyObject_GC_Del},
    {0, 0}
};
static PyType_Spec SbkEnumType_Type_spec = {
    "Shiboken.EnumType",
    0,    // filled in later
    sizeof(PyMemberDef),
    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_CHECKTYPES,
    SbkEnumType_Type_slots,
};


PyTypeObject *SbkEnumType_TypeF(void)
{
    static PyTypeObject *type = nullptr;
    if (!type) {
        SbkEnumType_Type_spec.basicsize =
            PepHeapType_SIZE + sizeof(SbkEnumTypePrivate);
        type = (PyTypeObject *)PyType_FromSpec(&SbkEnumType_Type_spec);
    }
    return type;
}

void SbkEnumTypeDealloc(PyObject* pyObj)
{
    SbkEnumType* sbkType = reinterpret_cast<SbkEnumType*>(pyObj);

    PyObject_GC_UnTrack(pyObj);
    Py_TRASHCAN_SAFE_BEGIN(pyObj);
    if (PepType_SETP(sbkType)->converter) {
        Shiboken::Conversions::deleteConverter(PepType_SETP(sbkType)->converter);
    }
    Py_TRASHCAN_SAFE_END(pyObj);
}

PyObject* SbkEnumTypeTpNew(PyTypeObject* metatype, PyObject* args, PyObject* kwds)
{
    newfunc type_new = reinterpret_cast<newfunc>(PyType_GetSlot(&PyType_Type, Py_tp_new));
    SbkEnumType *newType = reinterpret_cast<SbkEnumType*>(type_new(metatype, args, kwds));
    if (!newType)
        return 0;
    return reinterpret_cast<PyObject*>(newType);
}

} // extern "C"

namespace Shiboken {

class DeclaredEnumTypes
{
public:
    DeclaredEnumTypes();
    ~DeclaredEnumTypes();
    static DeclaredEnumTypes& instance();
    void addEnumType(PyTypeObject* type);

private:
    DeclaredEnumTypes(const DeclaredEnumTypes&);
    DeclaredEnumTypes& operator=(const DeclaredEnumTypes&);
    std::list<PyTypeObject*> m_enumTypes;
};

namespace Enum {

bool check(PyObject* pyObj)
{
    return Py_TYPE(Py_TYPE(pyObj)) == SbkEnumType_TypeF();
}

PyObject* getEnumItemFromValue(PyTypeObject* enumType, long itemValue)
{
    PyObject *key, *value;
    Py_ssize_t pos = 0;
    PyObject *values = PyDict_GetItemString(PepType(enumType)->tp_dict, const_cast<char*>("values"));

    while (PyDict_Next(values, &pos, &key, &value)) {
        SbkEnumObject *obj = reinterpret_cast<SbkEnumObject *>(value);
        if (obj->ob_value == itemValue) {
            Py_INCREF(obj);
            return value;
        }
    }
    return 0;
}

static PyTypeObject* createEnum(const char* fullName, const char* cppName, const char* shortName, PyTypeObject* flagsType)
{
    PyTypeObject* enumType = newTypeWithName(fullName, cppName, flagsType);
    if (PyType_Ready(enumType) < 0)
        return 0;
    return enumType;
}

PyTypeObject* createGlobalEnum(PyObject* module, const char* name, const char* fullName, const char* cppName, PyTypeObject* flagsType)
{
    PyTypeObject* enumType = createEnum(fullName, cppName, name, flagsType);
    if (enumType && PyModule_AddObject(module, name, reinterpret_cast<PyObject *>(enumType)) < 0)
        return 0;
    if (flagsType && PyModule_AddObject(module, PepType_GetNameStr(flagsType),
            reinterpret_cast<PyObject *>(flagsType)) < 0)
        return 0;
    return enumType;
}

PyTypeObject* createScopedEnum(SbkObjectType* scope, const char* name, const char* fullName, const char* cppName, PyTypeObject* flagsType)
{
    PyTypeObject* enumType = createEnum(fullName, cppName, name, flagsType);
    if (enumType && PyDict_SetItemString(PepType(scope)->tp_dict, name,
            reinterpret_cast<PyObject *>(enumType)) < 0)
        return nullptr;
    if (flagsType && PyDict_SetItemString(PepType(scope)->tp_dict,
            PepType_GetNameStr(flagsType),
            reinterpret_cast<PyObject *>(flagsType)) < 0)
        return nullptr;
    return enumType;
}

static PyObject* createEnumItem(PyTypeObject* enumType, const char* itemName, long itemValue)
{
    PyObject* enumItem = newItem(enumType, itemValue, itemName);
    if (PyDict_SetItemString(PepType(enumType)->tp_dict, itemName, enumItem) < 0)
        return 0;
    Py_DECREF(enumItem);
    return enumItem;
}

bool createGlobalEnumItem(PyTypeObject* enumType, PyObject* module, const char* itemName, long itemValue)
{
    PyObject* enumItem = createEnumItem(enumType, itemName, itemValue);
    if (enumItem) {
        if (PyModule_AddObject(module, itemName, enumItem) < 0)
            return false;
        // @TODO This Py_DECREF causes crashes on exit with a debug Python interpreter, essentially
        // causing a use-after-free in the GC. This is now commented out to cause a memory leak
        // instead of a crash. Proper memory management of Enum types and items should be
        // implemented. See PYSIDE-488. This will require proper allocation and deallocation of
        // the underlying Enum PyHeapType, which is currently just deallocated at application exit.
        // Py_DECREF(enumItem);
        return true;
    }
    return false;
}

bool createScopedEnumItem(PyTypeObject *enumType, PyTypeObject *scope,
                          const char *itemName, long itemValue)
{
    if (PyObject *enumItem = createEnumItem(enumType, itemName, itemValue)) {
        if (PyDict_SetItemString(PepType(scope)->tp_dict, itemName, enumItem) < 0)
            return false;
        Py_DECREF(enumItem);
        return true;
    }
    return false;
}

bool createScopedEnumItem(PyTypeObject* enumType, SbkObjectType* scope, const char* itemName, long itemValue)
{
    return createScopedEnumItem(enumType, reinterpret_cast<PyTypeObject *>(scope), itemName, itemValue);
}

PyObject *
newItem(PyTypeObject *enumType, long itemValue, const char *itemName)
{
    bool newValue = true;
    SbkEnumObject* enumObj;
    if (!itemName) {
        enumObj = reinterpret_cast<SbkEnumObject*>(
                      getEnumItemFromValue(enumType, itemValue));
        if (enumObj)
            return reinterpret_cast<PyObject*>(enumObj);

        newValue = false;
    }

    enumObj = PyObject_New(SbkEnumObject, enumType);
    if (!enumObj)
        return 0;

    enumObj->ob_name = itemName ? PyBytes_FromString(itemName) : 0;
    enumObj->ob_value = itemValue;

    if (newValue) {
        PyObject* values = PyDict_GetItemString(PepType(enumType)->tp_dict, const_cast<char*>("values"));
        if (!values) {
            values = PyDict_New();
            PyDict_SetItemString(PepType(enumType)->tp_dict, const_cast<char*>("values"), values);
            Py_DECREF(values); // ^ values still alive, because setitemstring incref it
        }
        PyDict_SetItemString(values, itemName, reinterpret_cast<PyObject*>(enumObj));
    }

    return reinterpret_cast<PyObject*>(enumObj);
}

static PyType_Slot SbkNewType_slots[] = {
    {Py_tp_repr, (void *)SbkEnumObject_repr},
    {Py_tp_str, (void *)SbkEnumObject_repr},
    {Py_tp_getset, (void *)SbkEnumGetSetList},
    {Py_tp_new, (void *)SbkEnum_tp_new},
    {Py_nb_add, (void *)enum_add},
    {Py_nb_subtract, (void *)enum_subtract},
    {Py_nb_multiply, (void *)enum_multiply},
#ifndef IS_PY3K
    {Py_nb_divide, (void *)enum_divide},
#endif
    {Py_nb_positive, (void *)enum_int},
#ifdef IS_PY3K
    {Py_nb_bool, (void *)enum_bool},
#else
    {Py_nb_nonzero, (void *)enum_bool},
    {Py_nb_long, (void *)enum_int},
#endif
    {Py_nb_and, (void *)enum_and},
    {Py_nb_xor, (void *)enum_xor},
    {Py_nb_or, (void *)enum_or},
    {Py_nb_int, (void *)enum_int},
    {Py_nb_index, (void *)enum_int},
    {Py_tp_richcompare, (void *)enum_richcompare},
    {Py_tp_hash, (void *)enum_hash},
    {Py_tp_dealloc, (void *)SbkDummyDealloc},
    {0, 0}
};
static PyType_Spec SbkNewType_spec = {
    "missing Enum name", // to be inserted later
    sizeof(SbkEnumObject),
    0,
    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_CHECKTYPES,
    SbkNewType_slots,
};

static void
copyNumberMethods(PyTypeObject *flagsType,
                  PyType_Slot number_slots[],
                  int *pidx)
{
    int idx = *pidx;
#ifdef IS_PY3K
#  define SLOT slot
#else
#  define SLOT slot_
#endif
#define PUT_SLOT(name) \
    number_slots[idx].SLOT = (name);                                \
    number_slots[idx].pfunc = PyType_GetSlot(flagsType, (name));    \
    ++idx;

    PUT_SLOT(Py_nb_absolute);
    PUT_SLOT(Py_nb_add);
    PUT_SLOT(Py_nb_and);
#ifdef IS_PY3K
    PUT_SLOT(Py_nb_bool);
#else
    PUT_SLOT(Py_nb_nonzero);
#endif
    PUT_SLOT(Py_nb_divmod);
    PUT_SLOT(Py_nb_float);
    PUT_SLOT(Py_nb_floor_divide);
    PUT_SLOT(Py_nb_index);
    PUT_SLOT(Py_nb_inplace_add);
    PUT_SLOT(Py_nb_inplace_and);
    PUT_SLOT(Py_nb_inplace_floor_divide);
    PUT_SLOT(Py_nb_inplace_lshift);
    PUT_SLOT(Py_nb_inplace_multiply);
    PUT_SLOT(Py_nb_inplace_or);
    PUT_SLOT(Py_nb_inplace_power);
    PUT_SLOT(Py_nb_inplace_remainder);
    PUT_SLOT(Py_nb_inplace_rshift);
    PUT_SLOT(Py_nb_inplace_subtract);
    PUT_SLOT(Py_nb_inplace_true_divide);
    PUT_SLOT(Py_nb_inplace_xor);
    PUT_SLOT(Py_nb_int);
    PUT_SLOT(Py_nb_invert);
    PUT_SLOT(Py_nb_lshift);
    PUT_SLOT(Py_nb_multiply);
    PUT_SLOT(Py_nb_negative);
    PUT_SLOT(Py_nb_or);
    PUT_SLOT(Py_nb_positive);
    PUT_SLOT(Py_nb_power);
    PUT_SLOT(Py_nb_remainder);
    PUT_SLOT(Py_nb_rshift);
    PUT_SLOT(Py_nb_subtract);
    PUT_SLOT(Py_nb_true_divide);
    PUT_SLOT(Py_nb_xor);
#ifndef IS_PY3K
    PUT_SLOT(Py_nb_long);
    PUT_SLOT(Py_nb_divide);
#endif
#undef PUT_SLOT
    *pidx = idx;
}

PyTypeObject *
newTypeWithName(const char* name,
                const char* cppName,
                PyTypeObject *numbers_fromFlag)
{
    // Careful: PyType_FromSpec does not allocate the string.
    PyType_Slot newslots[99] = {};  // enough but not too big for the stack
    PyType_Spec *newspec = new PyType_Spec;
    newspec->name = strdup(name);
    newspec->basicsize = SbkNewType_spec.basicsize;
    newspec->itemsize = SbkNewType_spec.itemsize;
    newspec->flags = SbkNewType_spec.flags;
    // we must append all the number methods, so rebuild everything:
    int idx = 0;
    while (SbkNewType_slots[idx].SLOT) {
        newslots[idx].SLOT = SbkNewType_slots[idx].SLOT;
        newslots[idx].pfunc = SbkNewType_slots[idx].pfunc;
        ++idx;
    }
    if (numbers_fromFlag)
        copyNumberMethods(numbers_fromFlag, newslots, &idx);
    newspec->slots = newslots;
    PyTypeObject *type = reinterpret_cast<PyTypeObject *>(PyType_FromSpec(newspec));
    Py_TYPE(type) = SbkEnumType_TypeF();
    Py_INCREF(Py_TYPE(type));

    SbkEnumType* enumType = reinterpret_cast<SbkEnumType*>(type);
    PepType_SETP(enumType)->cppName = cppName;
    PepType_SETP(enumType)->converterPtr = &PepType_SETP(enumType)->converter;
    DeclaredEnumTypes::instance().addEnumType(type);
    return type;
}

const char* getCppName(PyTypeObject* enumType)
{
    assert(Py_TYPE(enumType) == SbkEnumType_TypeF());
    return PepType_SETP(reinterpret_cast<SbkEnumType*>(enumType))->cppName;
}

long int getValue(PyObject* enumItem)
{
    assert(Shiboken::Enum::check(enumItem));
    return reinterpret_cast<SbkEnumObject*>(enumItem)->ob_value;
}

void setTypeConverter(PyTypeObject* enumType, SbkConverter* converter)
{
    //reinterpret_cast<SbkEnumType*>(enumType)->converter = converter;
    *PepType_SGTP(enumType)->converter = converter;
}

SbkConverter* getTypeConverter(PyTypeObject* enumType)
{
    //return reinterpret_cast<SbkEnumType*>(enumType)->converter;
    return *PepType_SGTP(enumType)->converter;
}

} // namespace Enum

DeclaredEnumTypes& DeclaredEnumTypes::instance()
{
    static DeclaredEnumTypes me;
    return me;
}

DeclaredEnumTypes::DeclaredEnumTypes()
{
}

DeclaredEnumTypes::~DeclaredEnumTypes()
{
    std::list<PyTypeObject*>::const_iterator it = m_enumTypes.begin();
    for (; it != m_enumTypes.end(); ++it) {
        /*
         * PYSIDE-595: This was "delete *it;" before introducing 'PyType_FromSpec'.
         * XXX what should I do now?
         * Refcounts in tests are 30 or 0 at end.
         * When I add the default tp_dealloc, we get negative refcounts!
         * So right now I am doing nothing. Surely wrong but no crash.
         * See also the comment in function 'createGlobalEnumItem'.
         */
        //fprintf(stderr, "ttt %d %s\n", Py_REFCNT(*it), PepType(*it)->tp_name);
    }
    m_enumTypes.clear();
}

void DeclaredEnumTypes::addEnumType(PyTypeObject* type)
{
    m_enumTypes.push_back(type);
}

}
