plpy_plpymodule.c

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/*
 * the plpy module
 *
 * src/pl/plpython/plpy_plpymodule.c
 */

#include "postgres.h"

#include "mb/pg_wchar.h"
#include "utils/builtins.h"

#include "plpython.h"

#include "plpy_plpymodule.h"

#include "plpy_cursorobject.h"
#include "plpy_elog.h"
#include "plpy_planobject.h"
#include "plpy_resultobject.h"
#include "plpy_spi.h"
#include "plpy_subxactobject.h"


HTAB       *PLy_spi_exceptions = NULL;


static void PLy_add_exceptions(PyObject *plpy);
static void PLy_generate_spi_exceptions(PyObject *mod, PyObject *base);

/* module functions */
static PyObject *PLy_debug(PyObject *self, PyObject *args);
static PyObject *PLy_log(PyObject *self, PyObject *args);
static PyObject *PLy_info(PyObject *self, PyObject *args);
static PyObject *PLy_notice(PyObject *self, PyObject *args);
static PyObject *PLy_warning(PyObject *self, PyObject *args);
static PyObject *PLy_error(PyObject *self, PyObject *args);
static PyObject *PLy_fatal(PyObject *self, PyObject *args);
static PyObject *PLy_quote_literal(PyObject *self, PyObject *args);
static PyObject *PLy_quote_nullable(PyObject *self, PyObject *args);
static PyObject *PLy_quote_ident(PyObject *self, PyObject *args);


/* A list of all known exceptions, generated from backend/utils/errcodes.txt */
typedef struct ExceptionMap
{
    char       *name;
    char       *classname;
    int         sqlstate;
} ExceptionMap;

static const ExceptionMap exception_map[] = {
#include "spiexceptions.h"
    {NULL, NULL, 0}
};

static PyMethodDef PLy_methods[] = {
    /*
     * logging methods
     */
    {"debug", PLy_debug, METH_VARARGS, NULL},
    {"log", PLy_log, METH_VARARGS, NULL},
    {"info", PLy_info, METH_VARARGS, NULL},
    {"notice", PLy_notice, METH_VARARGS, NULL},
    {"warning", PLy_warning, METH_VARARGS, NULL},
    {"error", PLy_error, METH_VARARGS, NULL},
    {"fatal", PLy_fatal, METH_VARARGS, NULL},

    /*
     * create a stored plan
     */
    {"prepare", PLy_spi_prepare, METH_VARARGS, NULL},

    /*
     * execute a plan or query
     */
    {"execute", PLy_spi_execute, METH_VARARGS, NULL},

    /*
     * escaping strings
     */
    {"quote_literal", PLy_quote_literal, METH_VARARGS, NULL},
    {"quote_nullable", PLy_quote_nullable, METH_VARARGS, NULL},
    {"quote_ident", PLy_quote_ident, METH_VARARGS, NULL},

    /*
     * create the subtransaction context manager
     */
    {"subtransaction", PLy_subtransaction_new, METH_NOARGS, NULL},

    /*
     * create a cursor
     */
    {"cursor", PLy_cursor, METH_VARARGS, NULL},

    {NULL, NULL, 0, NULL}
};

static PyMethodDef PLy_exc_methods[] = {
    {NULL, NULL, 0, NULL}
};

#if PY_MAJOR_VERSION >= 3
static PyModuleDef PLy_module = {
    PyModuleDef_HEAD_INIT,      /* m_base */
    "plpy",                     /* m_name */
    NULL,                       /* m_doc */
    -1,                         /* m_size */
    PLy_methods,                /* m_methods */
};

static PyModuleDef PLy_exc_module = {
    PyModuleDef_HEAD_INIT,      /* m_base */
    "spiexceptions",            /* m_name */
    NULL,                       /* m_doc */
    -1,                         /* m_size */
    PLy_exc_methods,            /* m_methods */
    NULL,                       /* m_reload */
    NULL,                       /* m_traverse */
    NULL,                       /* m_clear */
    NULL                        /* m_free */
};

/*
 * Must have external linkage, because PyMODINIT_FUNC does dllexport on
 * Windows-like platforms.
 */
PyMODINIT_FUNC
PyInit_plpy(void)
{
    PyObject   *m;

    m = PyModule_Create(&PLy_module);
    if (m == NULL)
        return NULL;

    PLy_add_exceptions(m);

    return m;
}
#endif   /* PY_MAJOR_VERSION >= 3 */

void
PLy_init_plpy(void)
{
    PyObject   *main_mod,
               *main_dict,
               *plpy_mod;

#if PY_MAJOR_VERSION < 3
    PyObject   *plpy;
#endif

    /*
     * initialize plpy module
     */
    PLy_plan_init_type();
    PLy_result_init_type();
    PLy_subtransaction_init_type();
    PLy_cursor_init_type();

#if PY_MAJOR_VERSION >= 3
    PyModule_Create(&PLy_module);
    /* for Python 3 we initialized the exceptions in PyInit_plpy */
#else
    plpy = Py_InitModule("plpy", PLy_methods);
    PLy_add_exceptions(plpy);
#endif

    /* PyDict_SetItemString(plpy, "PlanType", (PyObject *) &PLy_PlanType); */

    /*
     * initialize main module, and add plpy
     */
    main_mod = PyImport_AddModule("__main__");
    main_dict = PyModule_GetDict(main_mod);
    plpy_mod = PyImport_AddModule("plpy");
    if (plpy_mod == NULL)
        PLy_elog(ERROR, "could not import \"plpy\" module");
    PyDict_SetItemString(main_dict, "plpy", plpy_mod);
    if (PyErr_Occurred())
        PLy_elog(ERROR, "could not import \"plpy\" module");
}

static void
PLy_add_exceptions(PyObject *plpy)
{
    PyObject   *excmod;
    HASHCTL     hash_ctl;

#if PY_MAJOR_VERSION < 3
    excmod = Py_InitModule("spiexceptions", PLy_exc_methods);
#else
    excmod = PyModule_Create(&PLy_exc_module);
#endif
    if (PyModule_AddObject(plpy, "spiexceptions", excmod) < 0)
        PLy_elog(ERROR, "could not add the spiexceptions module");

    /*
     * XXX it appears that in some circumstances the reference count of the
     * spiexceptions module drops to zero causing a Python assert failure when
     * the garbage collector visits the module. This has been observed on the
     * buildfarm. To fix this, add an additional ref for the module here.
     *
     * This shouldn't cause a memory leak - we don't want this garbage
     * collected, and this function shouldn't be called more than once per
     * backend.
     */
    Py_INCREF(excmod);

    PLy_exc_error = PyErr_NewException("plpy.Error", NULL, NULL);
    PLy_exc_fatal = PyErr_NewException("plpy.Fatal", NULL, NULL);
    PLy_exc_spi_error = PyErr_NewException("plpy.SPIError", NULL, NULL);

    if (PLy_exc_error == NULL ||
        PLy_exc_fatal == NULL ||
        PLy_exc_spi_error == NULL)
        PLy_elog(ERROR, "could not create the base SPI exceptions");

    Py_INCREF(PLy_exc_error);
    PyModule_AddObject(plpy, "Error", PLy_exc_error);
    Py_INCREF(PLy_exc_fatal);
    PyModule_AddObject(plpy, "Fatal", PLy_exc_fatal);
    Py_INCREF(PLy_exc_spi_error);
    PyModule_AddObject(plpy, "SPIError", PLy_exc_spi_error);

    memset(&hash_ctl, 0, sizeof(hash_ctl));
    hash_ctl.keysize = sizeof(int);
    hash_ctl.entrysize = sizeof(PLyExceptionEntry);
    hash_ctl.hash = tag_hash;
    PLy_spi_exceptions = hash_create("SPI exceptions", 256,
                                     &hash_ctl, HASH_ELEM | HASH_FUNCTION);

    PLy_generate_spi_exceptions(excmod, PLy_exc_spi_error);
}

/*
 * Add all the autogenerated exceptions as subclasses of SPIError
 */
static void
PLy_generate_spi_exceptions(PyObject *mod, PyObject *base)
{
    int         i;

    for (i = 0; exception_map[i].name != NULL; i++)
    {
        bool        found;
        PyObject   *exc;
        PLyExceptionEntry *entry;
        PyObject   *sqlstate;
        PyObject   *dict = PyDict_New();

        if (dict == NULL)
            PLy_elog(ERROR, "could not generate SPI exceptions");

        sqlstate = PyString_FromString(unpack_sql_state(exception_map[i].sqlstate));
        if (sqlstate == NULL)
            PLy_elog(ERROR, "could not generate SPI exceptions");

        PyDict_SetItemString(dict, "sqlstate", sqlstate);
        Py_DECREF(sqlstate);
        exc = PyErr_NewException(exception_map[i].name, base, dict);
        PyModule_AddObject(mod, exception_map[i].classname, exc);
        entry = hash_search(PLy_spi_exceptions, &exception_map[i].sqlstate,
                            HASH_ENTER, &found);
        entry->exc = exc;
        Assert(!found);
    }
}


/*
 * the python interface to the elog function
 * don't confuse these with PLy_elog
 */
static PyObject *PLy_output(volatile int, PyObject *, PyObject *);

PyObject *
PLy_debug(PyObject *self, PyObject *args)
{
    return PLy_output(DEBUG2, self, args);
}

PyObject *
PLy_log(PyObject *self, PyObject *args)
{
    return PLy_output(LOG, self, args);
}

PyObject *
PLy_info(PyObject *self, PyObject *args)
{
    return PLy_output(INFO, self, args);
}

PyObject *
PLy_notice(PyObject *self, PyObject *args)
{
    return PLy_output(NOTICE, self, args);
}

PyObject *
PLy_warning(PyObject *self, PyObject *args)
{
    return PLy_output(WARNING, self, args);
}

PyObject *
PLy_error(PyObject *self, PyObject *args)
{
    return PLy_output(ERROR, self, args);
}

PyObject *
PLy_fatal(PyObject *self, PyObject *args)
{
    return PLy_output(FATAL, self, args);
}

PyObject *
PLy_quote_literal(PyObject *self, PyObject *args)
{
    const char *str;
    char       *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "s", &str))
        return NULL;

    quoted = quote_literal_cstr(str);
    ret = PyString_FromString(quoted);
    pfree(quoted);

    return ret;
}

PyObject *
PLy_quote_nullable(PyObject *self, PyObject *args)
{
    const char *str;
    char       *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "z", &str))
        return NULL;

    if (str == NULL)
        return PyString_FromString("NULL");

    quoted = quote_literal_cstr(str);
    ret = PyString_FromString(quoted);
    pfree(quoted);

    return ret;
}

PyObject *
PLy_quote_ident(PyObject *self, PyObject *args)
{
    const char *str;
    const char *quoted;
    PyObject   *ret;

    if (!PyArg_ParseTuple(args, "s", &str))
        return NULL;

    quoted = quote_identifier(str);
    ret = PyString_FromString(quoted);

    return ret;
}

static PyObject *
PLy_output(volatile int level, PyObject *self, PyObject *args)
{
    PyObject   *volatile so;
    char       *volatile sv;
    volatile MemoryContext oldcontext;

    if (PyTuple_Size(args) == 1)
    {
        /*
         * Treat single argument specially to avoid undesirable ('tuple',)
         * decoration.
         */
        PyObject   *o;

        if (!PyArg_UnpackTuple(args, "plpy.elog", 1, 1, &o))
            PLy_elog(ERROR, "could not unpack arguments in plpy.elog");
        so = PyObject_Str(o);
    }
    else
        so = PyObject_Str(args);
    if (so == NULL || ((sv = PyString_AsString(so)) == NULL))
    {
        level = ERROR;
        sv = dgettext(TEXTDOMAIN, "could not parse error message in plpy.elog");
    }

    oldcontext = CurrentMemoryContext;
    PG_TRY();
    {
        pg_verifymbstr(sv, strlen(sv), false);
        elog(level, "%s", sv);
    }
    PG_CATCH();
    {
        ErrorData  *edata;

        MemoryContextSwitchTo(oldcontext);
        edata = CopyErrorData();
        FlushErrorState();

        /*
         * Note: If sv came from PyString_AsString(), it points into storage
         * owned by so.  So free so after using sv.
         */
        Py_XDECREF(so);

        /* Make Python raise the exception */
        PLy_exception_set(PLy_exc_error, "%s", edata->message);
        return NULL;
    }
    PG_END_TRY();

    Py_XDECREF(so);

    /*
     * return a legal object so the interpreter will continue on its merry way
     */
    Py_INCREF(Py_None);
    return Py_None;
}