kea/src/lib/dns/python/rrset_python.cc

// Copyright (C) 2010  Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

// $Id$

#include <dns/rrset.h>

//
// Declaration of the custom exceptions
// Initialization and addition of these go in the module init at the
// end
//
static PyObject* po_EmptyRRset;

//
// Definition of the classes
//

// For each class, we need a struct, a helper functions (init, destroy,
// and static wrappers around the methods we export), a list of methods,
// and a type description
using namespace isc::dns;

// RRset

// Using a shared_ptr here should not really be necessary (PyObject
// is already reference-counted), however internally on the cpp side,
// not doing so might result in problems, since we can't copy construct
// rrsets, adding them to messages results in a problem when the
// message is destroyed or cleared later
class s_RRset : public PyObject {
public:
    RRsetPtr rrset;
};

static int RRset_init(s_RRset* self, PyObject* args);
static void RRset_destroy(s_RRset* self);

static PyObject* RRset_getRdataCount(s_RRset* self);
static PyObject* RRset_getName(s_RRset* self);
static PyObject* RRset_getClass(s_RRset* self);
static PyObject* RRset_getType(s_RRset* self);
static PyObject* RRset_getTTL(s_RRset* self);
static PyObject* RRset_setName(s_RRset* self, PyObject* args);
static PyObject* RRset_setTTL(s_RRset* self, PyObject* args);
static PyObject* RRset_toText(s_RRset* self);
static PyObject* RRset_str(PyObject* self);
static PyObject* RRset_toWire(s_RRset* self, PyObject* args);
static PyObject* RRset_addRdata(s_RRset* self, PyObject* args);
static PyObject* RRset_getRdata(s_RRset* self);
// TODO: iterator?

static PyMethodDef RRset_methods[] = {
    { "get_rdata_count", reinterpret_cast<PyCFunction>(RRset_getRdataCount), METH_NOARGS,
      "Returns the number of rdata fields." },
    { "get_name", reinterpret_cast<PyCFunction>(RRset_getName), METH_NOARGS,
      "Returns the name of the RRset, as a Name object." },
    { "get_class", reinterpret_cast<PyCFunction>(RRset_getClass), METH_NOARGS,
      "Returns the class of the RRset as an RRClass object." },
    { "get_type", reinterpret_cast<PyCFunction>(RRset_getType), METH_NOARGS,
      "Returns the type of the RRset as an RRType object." },
    { "get_ttl", reinterpret_cast<PyCFunction>(RRset_getTTL), METH_NOARGS,
      "Returns the TTL of the RRset as an RRTTL object." },
    { "set_name", reinterpret_cast<PyCFunction>(RRset_setName), METH_VARARGS,
      "Sets the name of the RRset.\nTakes a Name object as an argument." },
    { "set_ttl", reinterpret_cast<PyCFunction>(RRset_setTTL), METH_VARARGS,
      "Sets the TTL of the RRset.\nTakes an RRTTL object as an argument." },
    { "to_text", reinterpret_cast<PyCFunction>(RRset_toText), METH_NOARGS,
      "Returns the text representation of the RRset as a string" },
    { "to_wire", reinterpret_cast<PyCFunction>(RRset_toWire), METH_VARARGS,
      "Converts the RRset object to wire format.\n"
      "The argument can be either a MessageRenderer or an object that "
      "implements the sequence interface. If the object is mutable "
      "(for instance a bytearray()), the wire data is added in-place.\n"
      "If it is not (for instance a bytes() object), a new object is "
      "returned" },
    { "add_rdata", reinterpret_cast<PyCFunction>(RRset_addRdata), METH_VARARGS,
      "Adds the rdata for one RR to the RRset.\nTakes an Rdata object as an argument" },
    { "get_rdata", reinterpret_cast<PyCFunction>(RRset_getRdata), METH_NOARGS,
      "Returns a List containing all Rdata elements" },
    { NULL, NULL, 0, NULL }
};

static PyTypeObject rrset_type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "pydnspp.RRset",
    sizeof(s_RRset),                    // tp_basicsize
    0,                                  // tp_itemsize
    (destructor)RRset_destroy,          // tp_dealloc
    NULL,                               // tp_print
    NULL,                               // tp_getattr
    NULL,                               // tp_setattr
    NULL,                               // tp_reserved
    NULL,                               // tp_repr
    NULL,                               // tp_as_number
    NULL,                               // tp_as_sequence
    NULL,                               // tp_as_mapping
    NULL,                               // tp_hash 
    NULL,                               // tp_call
    RRset_str,                          // tp_str
    NULL,                               // tp_getattro
    NULL,                               // tp_setattro
    NULL,                               // tp_as_buffer
    Py_TPFLAGS_DEFAULT,                 // tp_flags
    "The AbstractRRset class is an abstract base class that "
    "models a DNS RRset.\n\n"
    "An object of (a specific derived class of) AbstractRRset "
    "models an RRset as described in the DNS standard:\n"
    "A set of DNS resource records (RRs) of the same type and class. "
    "The standard requires the TTL of all RRs in an RRset be the same; "
    "this class follows that requirement.\n\n"
    "Note about duplicate RDATA: RFC2181 states that it's meaningless that an "
    "RRset contains two identical RRs and that name servers should suppress "
    "such duplicates.\n"
    "This class is not responsible for ensuring this requirement: For example, "
    "addRdata() method doesn't check if there's already RDATA identical "
    "to the one being added.\n"
    "This is because such checks can be expensive, and it's often easy to "
    "ensure the uniqueness requirement at the %data preparation phase "
    "(e.g. when loading a zone).",
    NULL,                               // tp_traverse
    NULL,                               // tp_clear
    NULL,                               // tp_richcompare
    0,                                  // tp_weaklistoffset
    NULL,                               // tp_iter
    NULL,                               // tp_iternext
    RRset_methods,                      // tp_methods
    NULL,                               // tp_members
    NULL,                               // tp_getset
    NULL,                               // tp_base
    NULL,                               // tp_dict
    NULL,                               // tp_descr_get
    NULL,                               // tp_descr_set
    0,                                  // tp_dictoffset
    (initproc)RRset_init,               // tp_init
    NULL,                               // tp_alloc
    PyType_GenericNew,                  // tp_new
    NULL,                               // tp_free
    NULL,                               // tp_is_gc
    NULL,                               // tp_bases
    NULL,                               // tp_mro
    NULL,                               // tp_cache
    NULL,                               // tp_subclasses
    NULL,                               // tp_weaklist
    NULL,                               // tp_del
    0                                   // tp_version_tag
};

static int
RRset_init(s_RRset* self, PyObject* args) {
    s_Name* name;
    s_RRClass* rrclass;
    s_RRType* rrtype;
    s_RRTTL* rrttl;

    if (PyArg_ParseTuple(args, "O!O!O!O!", &name_type, &name,
                                           &rrclass_type, &rrclass,
                                           &rrtype_type, &rrtype,
                                           &rrttl_type, &rrttl
       )) {
        self->rrset = RRsetPtr(new RRset(*name->name, *rrclass->rrclass,
                                *rrtype->rrtype, *rrttl->rrttl));
        return (0);
    }

    self->rrset = RRsetPtr();
    return (-1);
}

static void
RRset_destroy(s_RRset* self) {
    // Clear the shared_ptr so that its reference count is zero
    // before we call tp_free() (there is no direct release())
    self->rrset.reset();
    Py_TYPE(self)->tp_free(self);
}

static PyObject*
RRset_getRdataCount(s_RRset* self) {
    return (Py_BuildValue("I", self->rrset->getRdataCount()));
}

static PyObject*
RRset_getName(s_RRset* self) {
    s_Name* name;

    // is this the best way to do this?
    name = static_cast<s_Name*>(name_type.tp_alloc(&name_type, 0));
    if (name != NULL) {
        name->name = new Name(self->rrset->getName());
        if (name->name == NULL)
          {
            Py_DECREF(name);
            return (NULL);
          }
    }

    return (name);
}

static PyObject*
RRset_getClass(s_RRset* self) {
    s_RRClass* rrclass;

    rrclass = static_cast<s_RRClass*>(rrclass_type.tp_alloc(&rrclass_type, 0));
    if (rrclass != NULL) {
        rrclass->rrclass = new RRClass(self->rrset->getClass());
        if (rrclass->rrclass == NULL)
          {
            Py_DECREF(rrclass);
            return (NULL);
          }
    }

    return (rrclass);
}

static PyObject*
RRset_getType(s_RRset* self) {
    s_RRType* rrtype;

    rrtype = static_cast<s_RRType*>(rrtype_type.tp_alloc(&rrtype_type, 0));
    if (rrtype != NULL) {
        rrtype->rrtype = new RRType(self->rrset->getType());
        if (rrtype->rrtype == NULL)
          {
            Py_DECREF(rrtype);
            return (NULL);
          }
    }

    return (rrtype);
}

static PyObject*
RRset_getTTL(s_RRset* self) {
    s_RRTTL* rrttl;

    rrttl = static_cast<s_RRTTL*>(rrttl_type.tp_alloc(&rrttl_type, 0));
    if (rrttl != NULL) {
        rrttl->rrttl = new RRTTL(self->rrset->getTTL());
        if (rrttl->rrttl == NULL)
          {
            Py_DECREF(rrttl);
            return (NULL);
          }
    }

    return (rrttl);
}

static PyObject*
RRset_setName(s_RRset* self, PyObject* args) {
    s_Name* name;
    if (!PyArg_ParseTuple(args, "O!", &name_type, &name)) {
        return (NULL);
    }
    self->rrset->setName(*name->name);
    Py_RETURN_NONE;
}

static PyObject*
RRset_setTTL(s_RRset* self, PyObject* args) {
    s_RRTTL* rrttl;
    if (!PyArg_ParseTuple(args, "O!", &rrttl_type, &rrttl)) {
        return (NULL);
    }
    self->rrset->setTTL(*rrttl->rrttl);
    Py_RETURN_NONE;
}

static PyObject*
RRset_toText(s_RRset* self) {
    try {
        return (Py_BuildValue("s", self->rrset->toText().c_str()));
    } catch (const EmptyRRset& ers) {
        PyErr_SetString(po_EmptyRRset, ers.what());
        return (NULL);
    }
}

static PyObject*
RRset_str(PyObject* self) {
    // Simply call the to_text method we already defined
    return (PyObject_CallMethod(self,
                               const_cast<char*>("to_text"),
                                const_cast<char*>("")));
}

static PyObject*
RRset_toWire(s_RRset* self, PyObject* args) {
    PyObject* bytes;
    s_MessageRenderer* mr;

    try {
        if (PyArg_ParseTuple(args, "O", &bytes) && PySequence_Check(bytes)) {
            PyObject* bytes_o = bytes;
            
            OutputBuffer buffer(4096);
            self->rrset->toWire(buffer);
            PyObject* n = PyBytes_FromStringAndSize(static_cast<const char*>(buffer.getData()), buffer.getLength());
            PyObject* result = PySequence_InPlaceConcat(bytes_o, n);
            // We need to release the object we temporarily created here
            // to prevent memory leak
            Py_DECREF(n);
            return (result);
        } else if (PyArg_ParseTuple(args, "O!", &messagerenderer_type, &mr)) {
            self->rrset->toWire(*mr->messagerenderer);
            // If we return NULL it is seen as an error, so use this for
            // None returns
            Py_RETURN_NONE;
        }
    } catch (const EmptyRRset& ers) {
        PyErr_Clear();
        PyErr_SetString(po_EmptyRRset, ers.what());
        return (NULL);
    }
    PyErr_Clear();
    PyErr_SetString(PyExc_TypeError,
                    "toWire argument must be a sequence object or a MessageRenderer");
    return (NULL);
}

static PyObject*
RRset_addRdata(s_RRset* self, PyObject* args) {
    s_Rdata* rdata;
    if (!PyArg_ParseTuple(args, "O!", &rdata_type, &rdata)) {
        return (NULL);
    }
    try {
        self->rrset->addRdata(*rdata->rdata);
        Py_RETURN_NONE;
    } catch (const std::bad_cast&) {
        PyErr_Clear();
        PyErr_SetString(PyExc_TypeError,
                        "Rdata type to add must match type of RRset");
        return (NULL);
    }
}

static PyObject*
RRset_getRdata(s_RRset* self) {
    PyObject* list = PyList_New(0);

    RdataIteratorPtr it = self->rrset->getRdataIterator();

    for (; !it->isLast(); it->next()) {
        s_Rdata *rds = static_cast<s_Rdata*>(rdata_type.tp_alloc(&rdata_type, 0));
        if (rds != NULL) {
            // hmz them iterators/shared_ptrs and private constructors
            // make this a bit weird, so we create a new one with
            // the data available
            const Rdata *rd = &it->getCurrent();
            rds->rdata = createRdata(self->rrset->getType(), self->rrset->getClass(), *rd);
            PyList_Append(list, rds);
        } else {
            return (NULL);
        }
    }
    
    return (list);
}

// end of RRset


// Module Initialization, all statics are initialized here
bool
initModulePart_RRset(PyObject* mod) {
    // Add the exceptions to the module
    po_EmptyRRset = PyErr_NewException("pydnspp.EmptyRRset", NULL, NULL);
    PyModule_AddObject(mod, "EmptyRRset", po_EmptyRRset);

    // Add the enums to the module

    // Add the constants to the module

    // Add the classes to the module
    // We initialize the static description object with PyType_Ready(),
    // then add it to the module

    // NameComparisonResult
    if (PyType_Ready(&rrset_type) < 0) {
        return (false);
    }
    Py_INCREF(&rrset_type);
    PyModule_AddObject(mod, "RRset",
                       reinterpret_cast<PyObject*>(&rrset_type));
    
    return (true);
}