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 * Copyright (c) 2009-2021, Google LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Google LLC nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "python/extension_dict.h"

#include "python/message.h"
#include "python/protobuf.h"

// -----------------------------------------------------------------------------
// ExtensionDict
// -----------------------------------------------------------------------------

typedef struct {
  PyObject_HEAD
  PyObject* msg;  // Owning ref to our parent pessage.
} PyUpb_ExtensionDict;

PyObject* PyUpb_ExtensionDict_New(PyObject* msg) {
  PyUpb_ModuleState* state = PyUpb_ModuleState_Get();
  PyUpb_ExtensionDict* ext_dict =
      (void*)PyType_GenericAlloc(state->extension_dict_type, 0);
  ext_dict->msg = msg;
  Py_INCREF(ext_dict->msg);
  return &ext_dict->ob_base;
}

static PyObject* PyUpb_ExtensionDict_FindExtensionByName(PyObject* _self,
                                                         PyObject* key) {
  PyUpb_ExtensionDict* self = (PyUpb_ExtensionDict*)_self;
  const char* name = PyUpb_GetStrData(key);
  const upb_msgdef* m = PyUpb_CMessage_GetMsgdef(self->msg);
  const upb_filedef* file = upb_msgdef_file(m);
  const upb_symtab* symtab = upb_filedef_symtab(file);
  const upb_fielddef* ext = upb_symtab_lookupext(symtab, name);
  if (ext) {
    return PyUpb_FieldDescriptor_Get(ext);
  } else {
    Py_RETURN_NONE;
  }
}

static PyObject* PyUpb_ExtensionDict_FindExtensionByNumber(PyObject* _self,
                                                           PyObject* arg) {
  PyUpb_ExtensionDict* self = (PyUpb_ExtensionDict*)_self;
  const upb_msgdef* m = PyUpb_CMessage_GetMsgdef(self->msg);
  const upb_msglayout* l = upb_msgdef_layout(m);
  const upb_filedef* file = upb_msgdef_file(m);
  const upb_symtab* symtab = upb_filedef_symtab(file);
  const upb_extreg* reg = upb_symtab_extreg(symtab);
  int64_t number = PyLong_AsLong(arg);
  const upb_msglayout_ext* ext =
      (upb_msglayout_ext*)_upb_extreg_get(reg, l, number);
  if (ext) {
    const upb_fielddef* f = _upb_symtab_lookupextfield(symtab, ext);
    return PyUpb_FieldDescriptor_Get(f);
  } else {
    Py_RETURN_NONE;
  }
}

static void PyUpb_ExtensionDict_Dealloc(PyUpb_ExtensionDict* self) {
  PyUpb_CMessage_ClearExtensionDict(self->msg);
  Py_DECREF(self->msg);
  PyUpb_Dealloc(self);
}

static Py_ssize_t PyUpb_ExtensionDict_Length(PyObject* _self) {
  PyUpb_ExtensionDict* self = (PyUpb_ExtensionDict*)_self;
  upb_msg* msg = PyUpb_CMessage_GetIfReified(self->msg);
  return msg ? upb_msg_extcount(msg) : 0;
}

static PyObject* PyUpb_ExtensionDict_Subscript(PyObject* _self, PyObject* key) {
  PyUpb_ExtensionDict* self = (PyUpb_ExtensionDict*)_self;
  const upb_fielddef* f = PyUpb_FieldDescriptor_GetDef(key);
  if (!f) return NULL;
  if (!upb_fielddef_isextension(f)) {
    return PyErr_Format(PyExc_KeyError, "Field %s is not an extension\n",
                        upb_fielddef_fullname(f));
  }
  return PyUpb_CMessage_GetFieldValue(self->msg, f);
}

int PyUpb_ExtensionDict_AssignSubscript(PyObject* _self, PyObject* key,
                                        PyObject* val) {
  PyUpb_ExtensionDict* self = (PyUpb_ExtensionDict*)_self;
  const upb_fielddef* f = PyUpb_FieldDescriptor_GetDef(key);
  if (!f) return -1;
  if (!upb_fielddef_isextension(f)) {
    PyErr_Format(PyExc_KeyError, "Field %s is not an extension\n",
                 upb_fielddef_fullname(f));
    return -1;
  }
  return PyUpb_CMessage_SetFieldValue(self->msg, f, val);
}

static PyMethodDef PyUpb_ExtensionDict_Methods[] = {
    {"_FindExtensionByName", PyUpb_ExtensionDict_FindExtensionByName, METH_O,
     "Finds an extension by name."},
    {"_FindExtensionByNumber", PyUpb_ExtensionDict_FindExtensionByNumber,
     METH_O, "Finds an extension by number."},
    {NULL, NULL},
};

static PyType_Slot PyUpb_ExtensionDict_Slots[] = {
    {Py_tp_dealloc, PyUpb_ExtensionDict_Dealloc},
    {Py_tp_methods, PyUpb_ExtensionDict_Methods},
    //{Py_tp_getset, PyUpb_ExtensionDict_Getters},
    //{Py_tp_hash, PyObject_HashNotImplemented},
    //{Py_tp_richcompare, PyUpb_ExtensionDict_RichCompare},
    //{Py_tp_iter, PyUpb_ExtensionDict_GetIter},
    {Py_sq_length, PyUpb_ExtensionDict_Length},
    //{Py_sq_contains, PyUpb_ExtensionDict_Contains},
    {Py_mp_length, PyUpb_ExtensionDict_Length},
    {Py_mp_subscript, PyUpb_ExtensionDict_Subscript},
    {Py_mp_ass_subscript, PyUpb_ExtensionDict_AssignSubscript},
    {0, NULL}};

static PyType_Spec PyUpb_ExtensionDict_Spec = {
    PYUPB_MODULE_NAME ".ExtensionDict",  // tp_name
    sizeof(PyUpb_ExtensionDict),         // tp_basicsize
    0,                                   // tp_itemsize
    Py_TPFLAGS_DEFAULT,                  // tp_flags
    PyUpb_ExtensionDict_Slots,
};

// -----------------------------------------------------------------------------
// ExtensionIterator
// -----------------------------------------------------------------------------

typedef struct {
  PyObject_HEAD
  PyObject* arena;
} PyUpb_ExtensionIterator;

static void PyUpb_ExtensionIterator_Dealloc(PyUpb_ExtensionDict* self) {
  PyUpb_Dealloc(self);
}

static PyType_Slot PyUpb_ExtensionIterator_Slots[] = {
    {Py_tp_dealloc, PyUpb_ExtensionIterator_Dealloc},
    {Py_tp_iter, PyObject_SelfIter},
    //{Py_tp_iter, PyUpb_ExtensionIterator_GetIter},
    //{Py_tp_iternext, PyUpb_ExtensionIterator_IterNext},
    {0, NULL}};

static PyType_Spec PyUpb_ExtensionIterator_Spec = {
    PYUPB_MODULE_NAME ".ExtensionIterator",  // tp_name
    sizeof(PyUpb_ExtensionDict),             // tp_basicsize
    0,                                       // tp_itemsize
    Py_TPFLAGS_DEFAULT,                      // tp_flags
    PyUpb_ExtensionIterator_Slots,
};

// -----------------------------------------------------------------------------
// Top Level
// -----------------------------------------------------------------------------

bool PyUpb_InitExtensionDict(PyObject* m) {
  PyUpb_ModuleState* s = PyUpb_ModuleState_GetFromModule(m);

  s->extension_dict_type = PyUpb_AddClass(m, &PyUpb_ExtensionDict_Spec);
  s->extension_iterator_type = PyUpb_AddClass(m, &PyUpb_ExtensionIterator_Spec);

  return s->extension_dict_type && s->extension_iterator_type;
}