py2go_converter.go

package py

/*
#include "Python.h"
#include "datetime.h"

int IsPyTypeUnicode(PyObject *o) {
  return PyUnicode_CheckExact(o);
}
*/
import "C"
import (
	"time"
	"unsafe"

	"gopkg.in/sensorbee/sensorbee.v0/data"
)

func isPyTypeUnicode(o *C.PyObject) int {
	return int(C.IsPyTypeUnicode(o))
}

func fromPyArray(ls *C.PyObject) (data.Array, error) {
	size := int(C.PyList_Size(ls))
	array := make(data.Array, size)
	for i := 0; i < size; i++ {
		o := C.PyList_GetItem(ls, C.Py_ssize_t(i))
		v, err := fromPyTypeObject(o)
		if err != nil {
			return nil, err
		}
		array[i] = v
	}
	return array, nil
}

func fromPyMap(o *C.PyObject) (data.Map, error) {
	m := data.Map{}

	var key, value *C.PyObject
	pos := C.Py_ssize_t(C.int(0))

	for C.int(C.PyDict_Next(o, &pos, &key, &value)) > 0 {
		// data.Map's key is only allowed string or unicode
		if isPyTypeString(key) == 0 && isPyTypeUnicode(key) == 0 {
			continue
		}
		k, _ := fromPyTypeObject(key)
		key, _ := data.ToString(k)
		v, err := fromPyTypeObject(value)
		if err != nil {
			return nil, err
		}
		m[key] = v
	}

	return m, nil
}

func fromPyTuple(o *C.PyObject) (data.Array, error) {
	size := int(C.PyTuple_Size(o))
	array := make(data.Array, size)
	for i := 0; i < size; i++ {
		o := C.PyTuple_GetItem(o, C.Py_ssize_t(i))
		v, err := fromPyTypeObject(o)
		if err != nil {
			return nil, err
		}
		array[i] = v
	}
	return array, nil
}

func fromTimestamp(o *C.PyObject) data.Timestamp {
	// FIXME: this internal code should not use
	d := (*C.PyDateTime_DateTime)(unsafe.Pointer(o))
	t := time.Date(int(d.data[0])<<8|int(d.data[1]), time.Month(int(d.data[2])+1),
		int(d.data[3]), int(d.data[4]), int(d.data[5]), int(d.data[6]),
		(int(d.data[7])<<16|int(d.data[8])<<8|int(d.data[9]))*1000,
		time.UTC)

	if d.hastzinfo <= 0 {
		return data.Timestamp(t)
	}

	return fromTimestampWithTimezone(o, t)
}

// fromTimestampWithTimezone converts into data.Timestamp with UTC time zone
// from datetime with tzinfo.  All of datetime passed to Go from Python API
// must be unified into UTC time zone by this function.
//
// This function calls `utcoffset` method to acquire offset from UTC for
// adjusting time zone.
func fromTimestampWithTimezone(o *C.PyObject, t time.Time) data.Timestamp {
	pyFunc, err := getPyFunc(o, "utcoffset")
	if err != nil {
		// Cannot get `utcoffset` function
		return data.Timestamp(t)
	}
	defer pyFunc.decRef()

	ret, err := pyFunc.callObject(Object{})
	if ret.p == nil && err != nil {
		// Failed to execute `utcoffset` function
		return data.Timestamp(t)
	}

	if !isPyTypeTimeDelta(ret.p) {
		// Cannot get `datetime.timedelta` instance
		return data.Timestamp(t)
	}

	// Adjust for time zone
	delta := (*C.PyDateTime_Delta)(unsafe.Pointer(ret.p))
	t = t.AddDate(0, 0, -int(delta.days))
	t = t.Add(time.Duration(-delta.seconds)*time.Second +
		time.Duration(-delta.microseconds)*time.Microsecond)
	return data.Timestamp(t)
}