plpython.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

		}
	}

	if (rv < 0)
	{
		PLy_exception_set(PLy_exc_spi_error,
						  "SPI_execute_plan failed: %s",
						  SPI_result_code_string(rv));
		return NULL;
	}

	return PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
}

static PyObject *
PLy_spi_execute_query(char *query, long limit)
{
	int			rv;
	MemoryContext oldcontext;

	oldcontext = CurrentMemoryContext;
	PG_TRY();
	{
		rv = SPI_execute(query, PLy_curr_procedure->fn_readonly, limit);
	}
	PG_CATCH();
	{
		MemoryContextSwitchTo(oldcontext);
		PLy_error_in_progress = CopyErrorData();
		FlushErrorState();
		if (!PyErr_Occurred())
			PyErr_SetString(PLy_exc_spi_error,
							"Unknown error in PLy_spi_execute_query");
		/* XXX this oughta be replaced with errcontext mechanism */
		PLy_elog(WARNING, "in function %s:",
				 PLy_procedure_name(PLy_curr_procedure));
		return NULL;
	}
	PG_END_TRY();

	if (rv < 0)
	{
		PLy_exception_set(PLy_exc_spi_error,
						  "SPI_execute failed: %s",
						  SPI_result_code_string(rv));
		return NULL;
	}

	return PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
}

static PyObject *
PLy_spi_execute_fetch_result(SPITupleTable *tuptable, int rows, int status)
{
	PLyResultObject *result;
	MemoryContext oldcontext;

	result = (PLyResultObject *) PLy_result_new();
	Py_DECREF(result->status);
	result->status = PyInt_FromLong(status);

	if (status == SPI_OK_UTILITY)
	{
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(0);
	}
	else if (status != SPI_OK_SELECT)
	{
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(rows);
	}
	else
	{
		PLyTypeInfo args;
		int			i;

		PLy_typeinfo_init(&args);
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(rows);

		oldcontext = CurrentMemoryContext;
		PG_TRY();
		{
			if (rows)
			{
				Py_DECREF(result->rows);
				result->rows = PyList_New(rows);

				PLy_input_tuple_funcs(&args, tuptable->tupdesc);
				for (i = 0; i < rows; i++)
				{
					PyObject   *row = PLyDict_FromTuple(&args, tuptable->vals[i],
														tuptable->tupdesc);

					PyList_SetItem(result->rows, i, row);
				}
				PLy_typeinfo_dealloc(&args);

				SPI_freetuptable(tuptable);
			}
		}
		PG_CATCH();
		{
			MemoryContextSwitchTo(oldcontext);
			PLy_error_in_progress = CopyErrorData();
			FlushErrorState();
			if (!PyErr_Occurred())
				PyErr_SetString(PLy_exc_error,
							"Unknown error in PLy_spi_execute_fetch_result");
			Py_DECREF(result);
			PLy_typeinfo_dealloc(&args);
			return NULL;
		}
		PG_END_TRY();
	}

	return (PyObject *) result;
}


/*
 * language handler and interpreter initialization
 */

/*
 * plpython_init()			- Initialize everything that can be
 *							  safely initialized during postmaster
 *							  startup.
 *
 * DO NOT make this static --- it has to be callable by preload
 */
void
plpython_init(void)
{
	static volatile int init_active = 0;

	/* Do initialization only once */
	if (!PLy_first_call)
		return;

	if (init_active)
		elog(FATAL, "initialization of language module failed");
	init_active = 1;

	Py_Initialize();
	PLy_init_interp();
	PLy_init_plpy();
	if (PyErr_Occurred())
		PLy_elog(FATAL, "untrapped error in initialization");
	PLy_procedure_cache = PyDict_New();
	if (PLy_procedure_cache == NULL)
		PLy_elog(ERROR, "could not create procedure cache");

	PLy_first_call = 0;
}

static void
PLy_init_all(void)
{
	/* Execute postmaster-startup safe initialization */
	if (PLy_first_call)
		plpython_init();

	/*
	 * Any other initialization that must be done each time a new backend
	 * starts -- currently none
	 */

}

static void
PLy_init_interp(void)
{
	PyObject   *mainmod;

	mainmod = PyImport_AddModule("__main__");
	if ((mainmod == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "could not import \"__main__\" module.");
	Py_INCREF(mainmod);
	PLy_interp_globals = PyModule_GetDict(mainmod);
	PLy_interp_safe_globals = PyDict_New();
	PyDict_SetItemString(PLy_interp_globals, "GD", PLy_interp_safe_globals);
	Py_DECREF(mainmod);
	if ((PLy_interp_globals == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "could not initialize globals");
}

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

	/*
	 * initialize plpy module
	 */
	PLy_PlanType.ob_type = PLy_ResultType.ob_type = &PyType_Type;
	plpy = Py_InitModule("plpy", PLy_methods);
	plpy_dict = PyModule_GetDict(plpy);

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

	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);
	PyDict_SetItemString(plpy_dict, "Error", PLy_exc_error);
	PyDict_SetItemString(plpy_dict, "Fatal", PLy_exc_fatal);
	PyDict_SetItemString(plpy_dict, "SPIError", PLy_exc_spi_error);

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

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

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

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

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

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

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

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

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


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

	so = PyObject_Str(args);
	if ((so == NULL) || ((sv = PyString_AsString(so)) == NULL))
	{
		level = ERROR;
		sv = "Unable to parse error message in `plpy.elog'";
	}

	oldcontext = CurrentMemoryContext;
	PG_TRY();
	{
		elog(level, "%s", sv);
	}
	PG_CATCH();
	{
		MemoryContextSwitchTo(oldcontext);
		PLy_error_in_progress = CopyErrorData();
		FlushErrorState();
		Py_XDECREF(so);

		/*
		 * returning NULL here causes the python interpreter to bail. when
		 * control passes back to PLy_procedure_call, we check for PG
		 * exceptions and re-throw the error.
		 */
		PyErr_SetString(PLy_exc_error, sv);
		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;
}


/*
 * Get the last procedure name called by the backend ( the innermost,
 * If a plpython procedure call calls the backend and the backend calls
 * another plpython procedure )
 *
 * NB: this returns SQL name, not the internal Python procedure name
 */

static char *
PLy_procedure_name(PLyProcedure * proc)
{
	if (proc == NULL)
		return "<unknown procedure>";
	return proc->proname;
}

/* output a python traceback/exception via the postgresql elog
 * function.  not pretty.
 */
static void
PLy_exception_set(PyObject * exc, const char *fmt,...)
{
	char		buf[1024];
	va_list		ap;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	PyErr_SetString(exc, buf);
}

/* Emit a PG error or notice, together with any available info about the
 * current Python error.  This should be used to propagate Python errors
 * into PG.
 */
static void
PLy_elog(int elevel, const char *fmt,...)
{
	va_list		ap;
	char	   *xmsg,
			   *emsg;
	int			xlevel;

	xmsg = PLy_traceback(&xlevel);

	va_start(ap, fmt);
	emsg = PLy_vprintf(fmt, ap);
	va_end(ap);

	PG_TRY();
	{
		ereport(elevel,
				(errmsg("plpython: %s", emsg),
				 (xmsg) ? errdetail("%s", xmsg) : 0));
	}
	PG_CATCH();
	{
		PLy_free(emsg);
		if (xmsg)
			PLy_free(xmsg);
		PG_RE_THROW();
	}
	PG_END_TRY();

	PLy_free(emsg);
	if (xmsg)
		PLy_free(xmsg);
}

static char *
PLy_traceback(int *xlevel)
{
	PyObject   *e,
			   *v,
			   *tb;
	PyObject   *eob,
			   *vob = NULL;
	char	   *vstr,
			   *estr,
			   *xstr = NULL;

	/*
	 * get the current exception
	 */
	PyErr_Fetch(&e, &v, &tb);

	/*
	 * oops, no exception, return
	 */
	if (e == NULL)
	{
		*xlevel = WARNING;
		return NULL;
	}

	PyErr_NormalizeException(&e, &v, &tb);
	Py_XDECREF(tb);

	eob = PyObject_Str(e);
	if ((v) && ((vob = PyObject_Str(v)) != NULL))
		vstr = PyString_AsString(vob);
	else
		vstr = "Unknown";

	/*
	 * I'm not sure what to do if eob is NULL here -- we can't call PLy_elog
	 * because that function calls us, so we could end up with infinite
	 * recursion.  I'm not even sure if eob could be NULL here -- would an
	 * Assert() be more appropriate?
	 */
	estr = eob ? PyString_AsString(eob) : "Unknown Exception";
	xstr = PLy_printf("%s: %s", estr, vstr);

	Py_DECREF(eob);
	Py_XDECREF(vob);
	Py_XDECREF(v);

	/*
	 * intuit an appropriate error level based on the exception type
	 */
	if ((PLy_exc_error) && (PyErr_GivenExceptionMatches(e, PLy_exc_error)))
		*xlevel = ERROR;
	else if ((PLy_exc_fatal) && (PyErr_GivenExceptionMatches(e, PLy_exc_fatal)))
		*xlevel = FATAL;
	else
		*xlevel = ERROR;

	Py_DECREF(e);
	return xstr;
}

static char *
PLy_printf(const char *fmt,...)
{
	va_list		ap;
	char	   *emsg;

	va_start(ap, fmt);
	emsg = PLy_vprintf(fmt, ap);
	va_end(ap);
	return emsg;
}

static char *
PLy_vprintf(const char *fmt, va_list ap)
{
	size_t		blen;
	int			bchar,
				tries = 2;
	char	   *buf;

	blen = strlen(fmt) * 2;
	if (blen < 256)
		blen = 256;
	buf = PLy_malloc(blen * sizeof(char));

	while (1)
	{
		bchar = vsnprintf(buf, blen, fmt, ap);
		if ((bchar > 0) && (bchar < blen))
			return buf;
		if (tries-- <= 0)
			break;
		if (blen > 0)
			blen = bchar + 1;
		else
			blen *= 2;
		buf = PLy_realloc(buf, blen);
	}
	PLy_free(buf);
	return NULL;
}

/* python module code
 */


/* some dumb utility functions
 */

static void *
PLy_malloc(size_t bytes)
{
	void	   *ptr = malloc(bytes);

	if (ptr == NULL)
		ereport(FATAL,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));
	return ptr;
}

static void *
PLy_realloc(void *optr, size_t bytes)
{
	void	   *nptr = realloc(optr, bytes);

	if (nptr == NULL)
		ereport(FATAL,
				(errcode(ERRCODE_OUT_OF_MEMORY),
				 errmsg("out of memory")));
	return nptr;
}

/* define this away
 */
static void
PLy_free(void *ptr)
{
	free(ptr);
}