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cpython/Modules/_zoneinfo.c
Sam Gross f1d33dbddd
gh-125243: Fix ZoneInfo data race in free threading build (#125281) 
Lock `ZoneInfoType` to protect accesses to `ZONEINFO_STRONG_CACHE`.
Refactor the `tp_new` handler to use Argument Clinic so that we can just
use `@critical_section` annotations on the relevant functions.

Also use `PyDict_SetDefaultRef` instead of `PyDict_SetDefault` when
inserting into the `TIMEDELTA_CACHE`.
2024-10-13 16:17:51 -04:00

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#ifndef Py_BUILD_CORE_BUILTIN
# define Py_BUILD_CORE_MODULE 1
#endif
#include "Python.h"
#include "pycore_critical_section.h" // _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED()
#include "pycore_long.h" // _PyLong_GetOne()
#include "pycore_pyerrors.h" // _PyErr_ChainExceptions1()
#include "datetime.h" // PyDateTime_TZInfo
#include <stddef.h> // offsetof()
#include <stdint.h>
#include "clinic/_zoneinfo.c.h"
/*[clinic input]
module zoneinfo
class zoneinfo.ZoneInfo "PyObject *" "PyTypeObject *"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=d12c73c0eef36df8]*/
typedef struct TransitionRuleType TransitionRuleType;
typedef struct StrongCacheNode StrongCacheNode;
typedef struct {
PyObject *utcoff;
PyObject *dstoff;
PyObject *tzname;
long utcoff_seconds;
} _ttinfo;
typedef struct {
_ttinfo std;
_ttinfo dst;
int dst_diff;
TransitionRuleType *start;
TransitionRuleType *end;
unsigned char std_only;
} _tzrule;
typedef struct {
PyDateTime_TZInfo base;
PyObject *key;
PyObject *file_repr;
PyObject *weakreflist;
size_t num_transitions;
size_t num_ttinfos;
int64_t *trans_list_utc;
int64_t *trans_list_wall[2];
_ttinfo **trans_ttinfos; // References to the ttinfo for each transition
_ttinfo *ttinfo_before;
_tzrule tzrule_after;
_ttinfo *_ttinfos; // Unique array of ttinfos for ease of deallocation
unsigned char fixed_offset;
unsigned char source;
} PyZoneInfo_ZoneInfo;
struct TransitionRuleType {
int64_t (*year_to_timestamp)(TransitionRuleType *, int);
};
typedef struct {
TransitionRuleType base;
uint8_t month; /* 1 - 12 */
uint8_t week; /* 1 - 5 */
uint8_t day; /* 0 - 6 */
int16_t hour; /* -167 - 167, RFC 8536 §3.3.1 */
int8_t minute; /* signed 2 digits */
int8_t second; /* signed 2 digits */
} CalendarRule;
typedef struct {
TransitionRuleType base;
uint8_t julian; /* 0, 1 */
uint16_t day; /* 0 - 365 */
int16_t hour; /* -167 - 167, RFC 8536 §3.3.1 */
int8_t minute; /* signed 2 digits */
int8_t second; /* signed 2 digits */
} DayRule;
struct StrongCacheNode {
StrongCacheNode *next;
StrongCacheNode *prev;
PyObject *key;
PyObject *zone;
};
typedef struct {
PyTypeObject *ZoneInfoType;
// Imports
PyObject *io_open;
PyObject *_tzpath_find_tzfile;
PyObject *_common_mod;
// Caches
PyObject *TIMEDELTA_CACHE;
PyObject *ZONEINFO_WEAK_CACHE;
StrongCacheNode *ZONEINFO_STRONG_CACHE;
_ttinfo NO_TTINFO;
} zoneinfo_state;
// Constants
static const int EPOCHORDINAL = 719163;
static int DAYS_IN_MONTH[] = {
-1, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31,
};
static int DAYS_BEFORE_MONTH[] = {
-1, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
};
static const int SOURCE_NOCACHE = 0;
static const int SOURCE_CACHE = 1;
static const int SOURCE_FILE = 2;
static const size_t ZONEINFO_STRONG_CACHE_MAX_SIZE = 8;
// Forward declarations
static int
load_data(zoneinfo_state *state, PyZoneInfo_ZoneInfo *self,
PyObject *file_obj);
static void
utcoff_to_dstoff(size_t *trans_idx, long *utcoffs, long *dstoffs,
unsigned char *isdsts, size_t num_transitions,
size_t num_ttinfos);
static int
ts_to_local(size_t *trans_idx, int64_t *trans_utc, long *utcoff,
int64_t *trans_local[2], size_t num_ttinfos,
size_t num_transitions);
static int
parse_tz_str(zoneinfo_state *state, PyObject *tz_str_obj, _tzrule *out);
static int
parse_abbr(const char **p, PyObject **abbr);
static int
parse_tz_delta(const char **p, long *total_seconds);
static int
parse_transition_time(const char **p, int *hour, int *minute, int *second);
static int
parse_transition_rule(const char **p, TransitionRuleType **out);
static _ttinfo *
find_tzrule_ttinfo(_tzrule *rule, int64_t ts, unsigned char fold, int year);
static _ttinfo *
find_tzrule_ttinfo_fromutc(_tzrule *rule, int64_t ts, int year,
unsigned char *fold);
static int
build_ttinfo(zoneinfo_state *state, long utcoffset, long dstoffset,
PyObject *tzname, _ttinfo *out);
static void
xdecref_ttinfo(_ttinfo *ttinfo);
static int
ttinfo_eq(const _ttinfo *const tti0, const _ttinfo *const tti1);
static int
build_tzrule(zoneinfo_state *state, PyObject *std_abbr, PyObject *dst_abbr,
long std_offset, long dst_offset, TransitionRuleType *start,
TransitionRuleType *end, _tzrule *out);
static void
free_tzrule(_tzrule *tzrule);
static PyObject *
load_timedelta(zoneinfo_state *state, long seconds);
static int
get_local_timestamp(PyObject *dt, int64_t *local_ts);
static _ttinfo *
find_ttinfo(zoneinfo_state *state, PyZoneInfo_ZoneInfo *self, PyObject *dt);
static int
ymd_to_ord(int y, int m, int d);
static int
is_leap_year(int year);
static size_t
_bisect(const int64_t value, const int64_t *arr, size_t size);
static int
eject_from_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *key);
static void
clear_strong_cache(zoneinfo_state *state, const PyTypeObject *const type);
static void
update_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *key, PyObject *zone);
static PyObject *
zone_from_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *const key);
static inline zoneinfo_state *
zoneinfo_get_state(PyObject *mod)
{
zoneinfo_state *state = (zoneinfo_state *)PyModule_GetState(mod);
assert(state != NULL);
return state;
}
static inline zoneinfo_state *
zoneinfo_get_state_by_cls(PyTypeObject *cls)
{
zoneinfo_state *state = (zoneinfo_state *)_PyType_GetModuleState(cls);
assert(state != NULL);
return state;
}
static struct PyModuleDef zoneinfomodule;
static inline zoneinfo_state *
zoneinfo_get_state_by_self(PyTypeObject *self)
{
PyObject *mod = PyType_GetModuleByDef(self, &zoneinfomodule);
assert(mod != NULL);
return zoneinfo_get_state(mod);
}
static PyObject *
zoneinfo_new_instance(zoneinfo_state *state, PyTypeObject *type, PyObject *key)
{
PyObject *file_obj = NULL;
PyObject *file_path = NULL;
file_path = PyObject_CallFunctionObjArgs(state->_tzpath_find_tzfile,
key, NULL);
if (file_path == NULL) {
return NULL;
}
else if (file_path == Py_None) {
PyObject *meth = state->_common_mod;
file_obj = PyObject_CallMethod(meth, "load_tzdata", "O", key);
if (file_obj == NULL) {
Py_DECREF(file_path);
return NULL;
}
}
PyObject *self = (PyObject *)(type->tp_alloc(type, 0));
if (self == NULL) {
goto error;
}
if (file_obj == NULL) {
PyObject *func = state->io_open;
file_obj = PyObject_CallFunction(func, "Os", file_path, "rb");
if (file_obj == NULL) {
goto error;
}
}
if (load_data(state, (PyZoneInfo_ZoneInfo *)self, file_obj)) {
goto error;
}
PyObject *rv = PyObject_CallMethod(file_obj, "close", NULL);
Py_SETREF(file_obj, NULL);
if (rv == NULL) {
goto error;
}
Py_DECREF(rv);
((PyZoneInfo_ZoneInfo *)self)->key = Py_NewRef(key);
goto cleanup;
error:
Py_CLEAR(self);
cleanup:
if (file_obj != NULL) {
PyObject *exc = PyErr_GetRaisedException();
PyObject *tmp = PyObject_CallMethod(file_obj, "close", NULL);
_PyErr_ChainExceptions1(exc);
if (tmp == NULL) {
Py_CLEAR(self);
}
Py_XDECREF(tmp);
Py_DECREF(file_obj);
}
Py_DECREF(file_path);
return self;
}
static PyObject *
get_weak_cache(zoneinfo_state *state, PyTypeObject *type)
{
if (type == state->ZoneInfoType) {
return state->ZONEINFO_WEAK_CACHE;
}
else {
PyObject *cache =
PyObject_GetAttrString((PyObject *)type, "_weak_cache");
// We are assuming that the type lives at least as long as the function
// that calls get_weak_cache, and that it holds a reference to the
// cache, so we'll return a "borrowed reference".
Py_XDECREF(cache);
return cache;
}
}
/*[clinic input]
@critical_section
@classmethod
zoneinfo.ZoneInfo.__new__
key: object
Create a new ZoneInfo instance.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_impl(PyTypeObject *type, PyObject *key)
/*[clinic end generated code: output=95e61dab86bb95c3 input=ef73d7a83bf8790e]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_self(type);
PyObject *instance = zone_from_strong_cache(state, type, key);
if (instance != NULL || PyErr_Occurred()) {
return instance;
}
PyObject *weak_cache = get_weak_cache(state, type);
instance = PyObject_CallMethod(weak_cache, "get", "O", key, Py_None);
if (instance == NULL) {
return NULL;
}
if (instance == Py_None) {
Py_DECREF(instance);
PyObject *tmp = zoneinfo_new_instance(state, type, key);
if (tmp == NULL) {
return NULL;
}
instance =
PyObject_CallMethod(weak_cache, "setdefault", "OO", key, tmp);
Py_DECREF(tmp);
if (instance == NULL) {
return NULL;
}
((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;
}
update_strong_cache(state, type, key, instance);
return instance;
}
static int
zoneinfo_traverse(PyZoneInfo_ZoneInfo *self, visitproc visit, void *arg)
{
Py_VISIT(Py_TYPE(self));
Py_VISIT(self->key);
return 0;
}
static int
zoneinfo_clear(PyZoneInfo_ZoneInfo *self)
{
Py_CLEAR(self->key);
Py_CLEAR(self->file_repr);
return 0;
}
static void
zoneinfo_dealloc(PyObject *obj_self)
{
PyZoneInfo_ZoneInfo *self = (PyZoneInfo_ZoneInfo *)obj_self;
PyTypeObject *tp = Py_TYPE(self);
PyObject_GC_UnTrack(self);
if (self->weakreflist != NULL) {
PyObject_ClearWeakRefs(obj_self);
}
if (self->trans_list_utc != NULL) {
PyMem_Free(self->trans_list_utc);
}
for (size_t i = 0; i < 2; i++) {
if (self->trans_list_wall[i] != NULL) {
PyMem_Free(self->trans_list_wall[i]);
}
}
if (self->_ttinfos != NULL) {
for (size_t i = 0; i < self->num_ttinfos; ++i) {
xdecref_ttinfo(&(self->_ttinfos[i]));
}
PyMem_Free(self->_ttinfos);
}
if (self->trans_ttinfos != NULL) {
PyMem_Free(self->trans_ttinfos);
}
free_tzrule(&(self->tzrule_after));
zoneinfo_clear(self);
tp->tp_free(obj_self);
Py_DECREF(tp);
}
/*[clinic input]
@classmethod
zoneinfo.ZoneInfo.from_file
cls: defining_class
file_obj: object
/
key: object = None
Create a ZoneInfo file from a file object.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_from_file_impl(PyTypeObject *type, PyTypeObject *cls,
PyObject *file_obj, PyObject *key)
/*[clinic end generated code: output=77887d1d56a48324 input=d26111f29eed6863]*/
{
PyObject *file_repr = NULL;
PyZoneInfo_ZoneInfo *self = NULL;
PyObject *obj_self = (PyObject *)(type->tp_alloc(type, 0));
self = (PyZoneInfo_ZoneInfo *)obj_self;
if (self == NULL) {
return NULL;
}
file_repr = PyObject_Repr(file_obj);
if (file_repr == NULL) {
goto error;
}
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
if (load_data(state, self, file_obj)) {
goto error;
}
self->source = SOURCE_FILE;
self->file_repr = file_repr;
self->key = Py_NewRef(key);
return obj_self;
error:
Py_XDECREF(file_repr);
Py_XDECREF(self);
return NULL;
}
/*[clinic input]
@classmethod
zoneinfo.ZoneInfo.no_cache
cls: defining_class
/
key: object
Get a new instance of ZoneInfo, bypassing the cache.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_no_cache_impl(PyTypeObject *type, PyTypeObject *cls,
PyObject *key)
/*[clinic end generated code: output=b0b09b3344c171b7 input=0238f3d56b1ea3f1]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
PyObject *out = zoneinfo_new_instance(state, type, key);
if (out != NULL) {
((PyZoneInfo_ZoneInfo *)out)->source = SOURCE_NOCACHE;
}
return out;
}
/*[clinic input]
@critical_section
@classmethod
zoneinfo.ZoneInfo.clear_cache
cls: defining_class
/
*
only_keys: object = None
Clear the ZoneInfo cache.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_clear_cache_impl(PyTypeObject *type, PyTypeObject *cls,
PyObject *only_keys)
/*[clinic end generated code: output=114d9b7c8a22e660 input=35944715df26d24e]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
PyObject *weak_cache = get_weak_cache(state, type);
if (only_keys == NULL || only_keys == Py_None) {
PyObject *rv = PyObject_CallMethod(weak_cache, "clear", NULL);
if (rv != NULL) {
Py_DECREF(rv);
}
clear_strong_cache(state, type);
}
else {
PyObject *item = NULL;
PyObject *pop = PyUnicode_FromString("pop");
if (pop == NULL) {
return NULL;
}
PyObject *iter = PyObject_GetIter(only_keys);
if (iter == NULL) {
Py_DECREF(pop);
return NULL;
}
while ((item = PyIter_Next(iter))) {
// Remove from strong cache
if (eject_from_strong_cache(state, type, item) < 0) {
Py_DECREF(item);
break;
}
// Remove from weak cache
PyObject *tmp = PyObject_CallMethodObjArgs(weak_cache, pop, item,
Py_None, NULL);
Py_DECREF(item);
if (tmp == NULL) {
break;
}
Py_DECREF(tmp);
}
Py_DECREF(iter);
Py_DECREF(pop);
}
if (PyErr_Occurred()) {
return NULL;
}
Py_RETURN_NONE;
}
/*[clinic input]
zoneinfo.ZoneInfo.utcoffset
cls: defining_class
dt: object
/
Retrieve a timedelta representing the UTC offset in a zone at the given datetime.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_utcoffset_impl(PyObject *self, PyTypeObject *cls,
PyObject *dt)
/*[clinic end generated code: output=b71016c319ba1f91 input=2bb6c5364938f19c]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
_ttinfo *tti = find_ttinfo(state, (PyZoneInfo_ZoneInfo *)self, dt);
if (tti == NULL) {
return NULL;
}
return Py_NewRef(tti->utcoff);
}
/*[clinic input]
zoneinfo.ZoneInfo.dst
cls: defining_class
dt: object
/
Retrieve a timedelta representing the amount of DST applied in a zone at the given datetime.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_dst_impl(PyObject *self, PyTypeObject *cls, PyObject *dt)
/*[clinic end generated code: output=cb6168d7723a6ae6 input=2167fb80cf8645c6]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
_ttinfo *tti = find_ttinfo(state, (PyZoneInfo_ZoneInfo *)self, dt);
if (tti == NULL) {
return NULL;
}
return Py_NewRef(tti->dstoff);
}
/*[clinic input]
zoneinfo.ZoneInfo.tzname
cls: defining_class
dt: object
/
Retrieve a string containing the abbreviation for the time zone that applies in a zone at a given datetime.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo_tzname_impl(PyObject *self, PyTypeObject *cls,
PyObject *dt)
/*[clinic end generated code: output=3b6ae6c3053ea75a input=15a59a4f92ed1f1f]*/
{
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
_ttinfo *tti = find_ttinfo(state, (PyZoneInfo_ZoneInfo *)self, dt);
if (tti == NULL) {
return NULL;
}
return Py_NewRef(tti->tzname);
}
#define GET_DT_TZINFO PyDateTime_DATE_GET_TZINFO
static PyObject *
zoneinfo_fromutc(PyObject *obj_self, PyObject *dt)
{
if (!PyDateTime_Check(dt)) {
PyErr_SetString(PyExc_TypeError,
"fromutc: argument must be a datetime");
return NULL;
}
if (GET_DT_TZINFO(dt) != obj_self) {
PyErr_SetString(PyExc_ValueError,
"fromutc: dt.tzinfo "
"is not self");
return NULL;
}
PyZoneInfo_ZoneInfo *self = (PyZoneInfo_ZoneInfo *)obj_self;
int64_t timestamp;
if (get_local_timestamp(dt, &timestamp)) {
return NULL;
}
size_t num_trans = self->num_transitions;
_ttinfo *tti = NULL;
unsigned char fold = 0;
if (num_trans >= 1 && timestamp < self->trans_list_utc[0]) {
tti = self->ttinfo_before;
}
else if (num_trans == 0 ||
timestamp > self->trans_list_utc[num_trans - 1]) {
tti = find_tzrule_ttinfo_fromutc(&(self->tzrule_after), timestamp,
PyDateTime_GET_YEAR(dt), &fold);
// Immediately after the last manual transition, the fold/gap is
// between self->trans_ttinfos[num_transitions - 1] and whatever
// ttinfo applies immediately after the last transition, not between
// the STD and DST rules in the tzrule_after, so we may need to
// adjust the fold value.
if (num_trans) {
_ttinfo *tti_prev = NULL;
if (num_trans == 1) {
tti_prev = self->ttinfo_before;
}
else {
tti_prev = self->trans_ttinfos[num_trans - 2];
}
int64_t diff = tti_prev->utcoff_seconds - tti->utcoff_seconds;
if (diff > 0 &&
timestamp < (self->trans_list_utc[num_trans - 1] + diff)) {
fold = 1;
}
}
}
else {
size_t idx = _bisect(timestamp, self->trans_list_utc, num_trans);
_ttinfo *tti_prev = NULL;
if (idx >= 2) {
tti_prev = self->trans_ttinfos[idx - 2];
tti = self->trans_ttinfos[idx - 1];
}
else {
tti_prev = self->ttinfo_before;
tti = self->trans_ttinfos[0];
}
// Detect fold
int64_t shift =
(int64_t)(tti_prev->utcoff_seconds - tti->utcoff_seconds);
if (shift > (timestamp - self->trans_list_utc[idx - 1])) {
fold = 1;
}
}
PyObject *tmp = PyNumber_Add(dt, tti->utcoff);
if (tmp == NULL) {
return NULL;
}
if (fold) {
if (PyDateTime_CheckExact(tmp)) {
((PyDateTime_DateTime *)tmp)->fold = 1;
dt = tmp;
}
else {
PyObject *replace = PyObject_GetAttrString(tmp, "replace");
Py_DECREF(tmp);
if (replace == NULL) {
return NULL;
}
PyObject *args = PyTuple_New(0);
if (args == NULL) {
Py_DECREF(replace);
return NULL;
}
PyObject *kwargs = PyDict_New();
if (kwargs == NULL) {
Py_DECREF(replace);
Py_DECREF(args);
return NULL;
}
dt = NULL;
if (!PyDict_SetItemString(kwargs, "fold", _PyLong_GetOne())) {
dt = PyObject_Call(replace, args, kwargs);
}
Py_DECREF(args);
Py_DECREF(kwargs);
Py_DECREF(replace);
if (dt == NULL) {
return NULL;
}
}
}
else {
dt = tmp;
}
return dt;
}
static PyObject *
zoneinfo_repr(PyZoneInfo_ZoneInfo *self)
{
PyObject *rv = NULL;
const char *type_name = Py_TYPE((PyObject *)self)->tp_name;
if (!(self->key == Py_None)) {
rv = PyUnicode_FromFormat("%s(key=%R)", type_name, self->key);
}
else {
assert(PyUnicode_Check(self->file_repr));
rv = PyUnicode_FromFormat("%s.from_file(%U)", type_name,
self->file_repr);
}
return rv;
}
static PyObject *
zoneinfo_str(PyZoneInfo_ZoneInfo *self)
{
if (!(self->key == Py_None)) {
return Py_NewRef(self->key);
}
else {
return zoneinfo_repr(self);
}
}
/* Pickles the ZoneInfo object by key and source.
*
* ZoneInfo objects are pickled by reference to the TZif file that they came
* from, which means that the exact transitions may be different or the file
* may not un-pickle if the data has changed on disk in the interim.
*
* It is necessary to include a bit indicating whether or not the object
* was constructed from the cache, because from-cache objects will hit the
* unpickling process's cache, whereas no-cache objects will bypass it.
*
* Objects constructed from ZoneInfo.from_file cannot be pickled.
*/
static PyObject *
zoneinfo_reduce(PyObject *obj_self, PyObject *unused)
{
PyZoneInfo_ZoneInfo *self = (PyZoneInfo_ZoneInfo *)obj_self;
if (self->source == SOURCE_FILE) {
// Objects constructed from files cannot be pickled.
PyObject *pickle_error =
_PyImport_GetModuleAttrString("pickle", "PicklingError");
if (pickle_error == NULL) {
return NULL;
}
PyErr_Format(pickle_error,
"Cannot pickle a ZoneInfo file from a file stream.");
Py_DECREF(pickle_error);
return NULL;
}
unsigned char from_cache = self->source == SOURCE_CACHE ? 1 : 0;
PyObject *constructor = PyObject_GetAttrString(obj_self, "_unpickle");
if (constructor == NULL) {
return NULL;
}
PyObject *rv = Py_BuildValue("O(OB)", constructor, self->key, from_cache);
Py_DECREF(constructor);
return rv;
}
/*[clinic input]
@classmethod
zoneinfo.ZoneInfo._unpickle
cls: defining_class
key: object
from_cache: unsigned_char(bitwise=True)
/
Private method used in unpickling.
[clinic start generated code]*/
static PyObject *
zoneinfo_ZoneInfo__unpickle_impl(PyTypeObject *type, PyTypeObject *cls,
PyObject *key, unsigned char from_cache)
/*[clinic end generated code: output=556712fc709deecb input=6ac8c73eed3de316]*/
{
if (from_cache) {
PyObject *rv;
Py_BEGIN_CRITICAL_SECTION(type);
rv = zoneinfo_ZoneInfo_impl(type, key);
Py_END_CRITICAL_SECTION();
return rv;
}
else {
zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
return zoneinfo_new_instance(state, type, key);
}
}
/* It is relatively expensive to construct new timedelta objects, and in most
* cases we're looking at a relatively small number of timedeltas, such as
* integer number of hours, etc. We will keep a cache so that we construct
* a minimal number of these.
*
* Possibly this should be replaced with an LRU cache so that it's not possible
* for the memory usage to explode from this, but in order for this to be a
* serious problem, one would need to deliberately craft a malicious time zone
* file with many distinct offsets. As of tzdb 2019c, loading every single zone
* fills the cache with ~450 timedeltas for a total size of ~12kB.
*
* This returns a new reference to the timedelta.
*/
static PyObject *
load_timedelta(zoneinfo_state *state, long seconds)
{
PyObject *rv;
PyObject *pyoffset = PyLong_FromLong(seconds);
if (pyoffset == NULL) {
return NULL;
}
if (PyDict_GetItemRef(state->TIMEDELTA_CACHE, pyoffset, &rv) == 0) {
PyObject *tmp = PyDateTimeAPI->Delta_FromDelta(
0, seconds, 0, 1, PyDateTimeAPI->DeltaType);
if (tmp != NULL) {
PyDict_SetDefaultRef(state->TIMEDELTA_CACHE, pyoffset, tmp, &rv);
Py_DECREF(tmp);
}
}
Py_DECREF(pyoffset);
return rv;
}
/* Constructor for _ttinfo object - this starts by initializing the _ttinfo
* to { NULL, NULL, NULL }, so that Py_XDECREF will work on partially
* initialized _ttinfo objects.
*/
static int
build_ttinfo(zoneinfo_state *state, long utcoffset, long dstoffset,
PyObject *tzname, _ttinfo *out)
{
out->utcoff = NULL;
out->dstoff = NULL;
out->tzname = NULL;
out->utcoff_seconds = utcoffset;
out->utcoff = load_timedelta(state, utcoffset);
if (out->utcoff == NULL) {
return -1;
}
out->dstoff = load_timedelta(state, dstoffset);
if (out->dstoff == NULL) {
return -1;
}
out->tzname = Py_NewRef(tzname);
return 0;
}
/* Decrease reference count on any non-NULL members of a _ttinfo */
static void
xdecref_ttinfo(_ttinfo *ttinfo)
{
if (ttinfo != NULL) {
Py_XDECREF(ttinfo->utcoff);
Py_XDECREF(ttinfo->dstoff);
Py_XDECREF(ttinfo->tzname);
}
}
/* Equality function for _ttinfo. */
static int
ttinfo_eq(const _ttinfo *const tti0, const _ttinfo *const tti1)
{
int rv;
if ((rv = PyObject_RichCompareBool(tti0->utcoff, tti1->utcoff, Py_EQ)) <
1) {
goto end;
}
if ((rv = PyObject_RichCompareBool(tti0->dstoff, tti1->dstoff, Py_EQ)) <
1) {
goto end;
}
if ((rv = PyObject_RichCompareBool(tti0->tzname, tti1->tzname, Py_EQ)) <
1) {
goto end;
}
end:
return rv;
}
/* Given a file-like object, this populates a ZoneInfo object
*
* The current version calls into a Python function to read the data from
* file into Python objects, and this translates those Python objects into
* C values and calculates derived values (e.g. dstoff) in C.
*
* This returns 0 on success and -1 on failure.
*
* The function will never return while `self` is partially initialized —
* the object only needs to be freed / deallocated if this succeeds.
*/
static int
load_data(zoneinfo_state *state, PyZoneInfo_ZoneInfo *self, PyObject *file_obj)
{
int rv = 0;
PyObject *data_tuple = NULL;
long *utcoff = NULL;
long *dstoff = NULL;
size_t *trans_idx = NULL;
unsigned char *isdst = NULL;
self->trans_list_utc = NULL;
self->trans_list_wall[0] = NULL;
self->trans_list_wall[1] = NULL;
self->trans_ttinfos = NULL;
self->_ttinfos = NULL;
self->file_repr = NULL;
size_t ttinfos_allocated = 0;
data_tuple = PyObject_CallMethod(state->_common_mod, "load_data", "O",
file_obj);
if (data_tuple == NULL) {
goto error;
}
if (!PyTuple_CheckExact(data_tuple)) {
PyErr_Format(PyExc_TypeError, "Invalid data result type: %r",
data_tuple);
goto error;
}
// Unpack the data tuple
PyObject *trans_idx_list = PyTuple_GetItem(data_tuple, 0);
if (trans_idx_list == NULL) {
goto error;
}
PyObject *trans_utc = PyTuple_GetItem(data_tuple, 1);
if (trans_utc == NULL) {
goto error;
}
PyObject *utcoff_list = PyTuple_GetItem(data_tuple, 2);
if (utcoff_list == NULL) {
goto error;
}
PyObject *isdst_list = PyTuple_GetItem(data_tuple, 3);
if (isdst_list == NULL) {
goto error;
}
PyObject *abbr = PyTuple_GetItem(data_tuple, 4);
if (abbr == NULL) {
goto error;
}
PyObject *tz_str = PyTuple_GetItem(data_tuple, 5);
if (tz_str == NULL) {
goto error;
}
// Load the relevant sizes
Py_ssize_t num_transitions = PyTuple_Size(trans_utc);
if (num_transitions < 0) {
goto error;
}
Py_ssize_t num_ttinfos = PyTuple_Size(utcoff_list);
if (num_ttinfos < 0) {
goto error;
}
self->num_transitions = (size_t)num_transitions;
self->num_ttinfos = (size_t)num_ttinfos;
// Load the transition indices and list
self->trans_list_utc =
PyMem_Malloc(self->num_transitions * sizeof(int64_t));
if (self->trans_list_utc == NULL) {
goto error;
}
trans_idx = PyMem_Malloc(self->num_transitions * sizeof(Py_ssize_t));
if (trans_idx == NULL) {
goto error;
}
for (size_t i = 0; i < self->num_transitions; ++i) {
PyObject *num = PyTuple_GetItem(trans_utc, i);
if (num == NULL) {
goto error;
}
self->trans_list_utc[i] = PyLong_AsLongLong(num);
if (self->trans_list_utc[i] == -1 && PyErr_Occurred()) {
goto error;
}
num = PyTuple_GetItem(trans_idx_list, i);
if (num == NULL) {
goto error;
}
Py_ssize_t cur_trans_idx = PyLong_AsSsize_t(num);
if (cur_trans_idx == -1) {
goto error;
}
trans_idx[i] = (size_t)cur_trans_idx;
if (trans_idx[i] > self->num_ttinfos) {
PyErr_Format(
PyExc_ValueError,
"Invalid transition index found while reading TZif: %zd",
cur_trans_idx);
goto error;
}
}
// Load UTC offsets and isdst (size num_ttinfos)
utcoff = PyMem_Malloc(self->num_ttinfos * sizeof(long));
isdst = PyMem_Malloc(self->num_ttinfos * sizeof(unsigned char));
if (utcoff == NULL || isdst == NULL) {
goto error;
}
for (size_t i = 0; i < self->num_ttinfos; ++i) {
PyObject *num = PyTuple_GetItem(utcoff_list, i);
if (num == NULL) {
goto error;
}
utcoff[i] = PyLong_AsLong(num);
if (utcoff[i] == -1 && PyErr_Occurred()) {
goto error;
}
num = PyTuple_GetItem(isdst_list, i);
if (num == NULL) {
goto error;
}
int isdst_with_error = PyObject_IsTrue(num);
if (isdst_with_error == -1) {
goto error;
}
else {
isdst[i] = (unsigned char)isdst_with_error;
}
}
dstoff = PyMem_Calloc(self->num_ttinfos, sizeof(long));
if (dstoff == NULL) {
goto error;
}
// Derive dstoff and trans_list_wall from the information we've loaded
utcoff_to_dstoff(trans_idx, utcoff, dstoff, isdst, self->num_transitions,
self->num_ttinfos);
if (ts_to_local(trans_idx, self->trans_list_utc, utcoff,
self->trans_list_wall, self->num_ttinfos,
self->num_transitions)) {
goto error;
}
// Build _ttinfo objects from utcoff, dstoff and abbr
self->_ttinfos = PyMem_Malloc(self->num_ttinfos * sizeof(_ttinfo));
if (self->_ttinfos == NULL) {
goto error;
}
for (size_t i = 0; i < self->num_ttinfos; ++i) {
PyObject *tzname = PyTuple_GetItem(abbr, i);
if (tzname == NULL) {
goto error;
}
ttinfos_allocated++;
int rc = build_ttinfo(state, utcoff[i], dstoff[i], tzname,
&(self->_ttinfos[i]));
if (rc) {
goto error;
}
}
// Build our mapping from transition to the ttinfo that applies
self->trans_ttinfos =
PyMem_Calloc(self->num_transitions, sizeof(_ttinfo *));
if (self->trans_ttinfos == NULL) {
goto error;
}
for (size_t i = 0; i < self->num_transitions; ++i) {
size_t ttinfo_idx = trans_idx[i];
assert(ttinfo_idx < self->num_ttinfos);
self->trans_ttinfos[i] = &(self->_ttinfos[ttinfo_idx]);
}
// Set ttinfo_before to the first non-DST transition
for (size_t i = 0; i < self->num_ttinfos; ++i) {
if (!isdst[i]) {
self->ttinfo_before = &(self->_ttinfos[i]);
break;
}
}
// If there are only DST ttinfos, pick the first one, if there are no
// ttinfos at all, set ttinfo_before to NULL
if (self->ttinfo_before == NULL && self->num_ttinfos > 0) {
self->ttinfo_before = &(self->_ttinfos[0]);
}
if (tz_str != Py_None && PyObject_IsTrue(tz_str)) {
if (parse_tz_str(state, tz_str, &(self->tzrule_after))) {
goto error;
}
}
else {
if (!self->num_ttinfos) {
PyErr_Format(PyExc_ValueError, "No time zone information found.");
goto error;
}
size_t idx;
if (!self->num_transitions) {
idx = self->num_ttinfos - 1;
}
else {
idx = trans_idx[self->num_transitions - 1];
}
_ttinfo *tti = &(self->_ttinfos[idx]);
build_tzrule(state, tti->tzname, NULL, tti->utcoff_seconds, 0, NULL,
NULL, &(self->tzrule_after));
// We've abused the build_tzrule constructor to construct an STD-only
// rule mimicking whatever ttinfo we've picked up, but it's possible
// that the one we've picked up is a DST zone, so we need to make sure
// that the dstoff is set correctly in that case.
if (PyObject_IsTrue(tti->dstoff)) {
_ttinfo *tti_after = &(self->tzrule_after.std);
Py_SETREF(tti_after->dstoff, Py_NewRef(tti->dstoff));
}
}
// Determine if this is a "fixed offset" zone, meaning that the output of
// the utcoffset, dst and tzname functions does not depend on the specific
// datetime passed.
//
// We make three simplifying assumptions here:
//
// 1. If tzrule_after is not std_only, it has transitions that might occur
// (it is possible to construct TZ strings that specify STD and DST but
// no transitions ever occur, such as AAA0BBB,0/0,J365/25).
// 2. If self->_ttinfos contains more than one _ttinfo object, the objects
// represent different offsets.
// 3. self->ttinfos contains no unused _ttinfos (in which case an otherwise
// fixed-offset zone with extra _ttinfos defined may appear to *not* be
// a fixed offset zone).
//
// Violations to these assumptions would be fairly exotic, and exotic
// zones should almost certainly not be used with datetime.time (the
// only thing that would be affected by this).
if (self->num_ttinfos > 1 || !self->tzrule_after.std_only) {
self->fixed_offset = 0;
}
else if (self->num_ttinfos == 0) {
self->fixed_offset = 1;
}
else {
int constant_offset =
ttinfo_eq(&(self->_ttinfos[0]), &self->tzrule_after.std);
if (constant_offset < 0) {
goto error;
}
else {
self->fixed_offset = constant_offset;
}
}
goto cleanup;
error:
// These resources only need to be freed if we have failed, if we succeed
// in initializing a PyZoneInfo_ZoneInfo object, we can rely on its dealloc
// method to free the relevant resources.
if (self->trans_list_utc != NULL) {
PyMem_Free(self->trans_list_utc);
self->trans_list_utc = NULL;
}
for (size_t i = 0; i < 2; ++i) {
if (self->trans_list_wall[i] != NULL) {
PyMem_Free(self->trans_list_wall[i]);
self->trans_list_wall[i] = NULL;
}
}
if (self->_ttinfos != NULL) {
for (size_t i = 0; i < ttinfos_allocated; ++i) {
xdecref_ttinfo(&(self->_ttinfos[i]));
}
PyMem_Free(self->_ttinfos);
self->_ttinfos = NULL;
}
if (self->trans_ttinfos != NULL) {
PyMem_Free(self->trans_ttinfos);
self->trans_ttinfos = NULL;
}
rv = -1;
cleanup:
Py_XDECREF(data_tuple);
if (utcoff != NULL) {
PyMem_Free(utcoff);
}
if (dstoff != NULL) {
PyMem_Free(dstoff);
}
if (isdst != NULL) {
PyMem_Free(isdst);
}
if (trans_idx != NULL) {
PyMem_Free(trans_idx);
}
return rv;
}
/* Function to calculate the local timestamp of a transition from the year. */
int64_t
calendarrule_year_to_timestamp(TransitionRuleType *base_self, int year)
{
CalendarRule *self = (CalendarRule *)base_self;
// We want (year, month, day of month); we have year and month, but we
// need to turn (week, day-of-week) into day-of-month
//
// Week 1 is the first week in which day `day` (where 0 = Sunday) appears.
// Week 5 represents the last occurrence of day `day`, so we need to know
// the first weekday of the month and the number of days in the month.
int8_t first_day = (ymd_to_ord(year, self->month, 1) + 6) % 7;
uint8_t days_in_month = DAYS_IN_MONTH[self->month];
if (self->month == 2 && is_leap_year(year)) {
days_in_month += 1;
}
// This equation seems magical, so I'll break it down:
// 1. calendar says 0 = Monday, POSIX says 0 = Sunday so we need first_day
// + 1 to get 1 = Monday -> 7 = Sunday, which is still equivalent
// because this math is mod 7
// 2. Get first day - desired day mod 7 (adjusting by 7 for negative
// numbers so that -1 % 7 = 6).
// 3. Add 1 because month days are a 1-based index.
int8_t month_day = ((int8_t)(self->day) - (first_day + 1)) % 7;
if (month_day < 0) {
month_day += 7;
}
month_day += 1;
// Now use a 0-based index version of `week` to calculate the w-th
// occurrence of `day`
month_day += ((int8_t)(self->week) - 1) * 7;
// month_day will only be > days_in_month if w was 5, and `w` means "last
// occurrence of `d`", so now we just check if we over-shot the end of the
// month and if so knock off 1 week.
if (month_day > days_in_month) {
month_day -= 7;
}
int64_t ordinal = ymd_to_ord(year, self->month, month_day) - EPOCHORDINAL;
return ordinal * 86400 + (int64_t)self->hour * 3600 +
(int64_t)self->minute * 60 + self->second;
}
/* Constructor for CalendarRule. */
int
calendarrule_new(int month, int week, int day, int hour,
int minute, int second, CalendarRule *out)
{
// These bounds come from the POSIX standard, which describes an Mm.n.d
// rule as:
//
// The d'th day (0 <= d <= 6) of week n of month m of the year (1 <= n <=
// 5, 1 <= m <= 12, where week 5 means "the last d day in month m" which
// may occur in either the fourth or the fifth week). Week 1 is the first
// week in which the d'th day occurs. Day zero is Sunday.
if (month < 1 || month > 12) {
PyErr_Format(PyExc_ValueError, "Month must be in [1, 12]");
return -1;
}
if (week < 1 || week > 5) {
PyErr_Format(PyExc_ValueError, "Week must be in [1, 5]");
return -1;
}
if (day < 0 || day > 6) {
PyErr_Format(PyExc_ValueError, "Day must be in [0, 6]");
return -1;
}
if (hour < -167 || hour > 167) {
PyErr_Format(PyExc_ValueError, "Hour must be in [0, 167]");
return -1;
}
TransitionRuleType base = {&calendarrule_year_to_timestamp};
CalendarRule new_offset = {
.base = base,
.month = (uint8_t)month,
.week = (uint8_t)week,
.day = (uint8_t)day,
.hour = (int16_t)hour,
.minute = (int8_t)minute,
.second = (int8_t)second,
};
*out = new_offset;
return 0;
}
/* Function to calculate the local timestamp of a transition from the year.
*
* This translates the day of the year into a local timestamp — either a
* 1-based Julian day, not including leap days, or the 0-based year-day,
* including leap days.
* */
int64_t
dayrule_year_to_timestamp(TransitionRuleType *base_self, int year)
{
// The function signature requires a TransitionRuleType pointer, but this
// function is only applicable to DayRule* objects.
DayRule *self = (DayRule *)base_self;
// ymd_to_ord calculates the number of days since 0001-01-01, but we want
// to know the number of days since 1970-01-01, so we must subtract off
// the equivalent of ymd_to_ord(1970, 1, 1).
//
// We subtract off an additional 1 day to account for January 1st (we want
// the number of full days *before* the date of the transition - partial
// days are accounted for in the hour, minute and second portions.
int64_t days_before_year = ymd_to_ord(year, 1, 1) - EPOCHORDINAL - 1;
// The Julian day specification skips over February 29th in leap years,
// from the POSIX standard:
//
// Leap days shall not be counted. That is, in all years-including leap
// years-February 28 is day 59 and March 1 is day 60. It is impossible to
// refer explicitly to the occasional February 29.
//
// This is actually more useful than you'd think — if you want a rule that
// always transitions on a given calendar day (other than February 29th),
// you would use a Julian day, e.g. J91 always refers to April 1st and J365
// always refers to December 31st.
uint16_t day = self->day;
if (self->julian && day >= 59 && is_leap_year(year)) {
day += 1;
}
return (days_before_year + day) * 86400 + (int64_t)self->hour * 3600 +
(int64_t)self->minute * 60 + self->second;
}
/* Constructor for DayRule. */
static int
dayrule_new(int julian, int day, int hour, int minute,
int second, DayRule *out)
{
// The POSIX standard specifies that Julian days must be in the range (1 <=
// n <= 365) and that non-Julian (they call it "0-based Julian") days must
// be in the range (0 <= n <= 365).
if (day < julian || day > 365) {
PyErr_Format(PyExc_ValueError, "day must be in [%d, 365], not: %d",
julian, day);
return -1;
}
if (hour < -167 || hour > 167) {
PyErr_Format(PyExc_ValueError, "Hour must be in [0, 167]");
return -1;
}
TransitionRuleType base = {
&dayrule_year_to_timestamp,
};
DayRule tmp = {
.base = base,
.julian = (uint8_t)julian,
.day = (int16_t)day,
.hour = (int16_t)hour,
.minute = (int8_t)minute,
.second = (int8_t)second,
};
*out = tmp;
return 0;
}
/* Calculate the start and end rules for a _tzrule in the given year. */
static void
tzrule_transitions(_tzrule *rule, int year, int64_t *start, int64_t *end)
{
assert(rule->start != NULL);
assert(rule->end != NULL);
*start = rule->start->year_to_timestamp(rule->start, year);
*end = rule->end->year_to_timestamp(rule->end, year);
}
/* Calculate the _ttinfo that applies at a given local time from a _tzrule.
*
* This takes a local timestamp and fold for disambiguation purposes; the year
* could technically be calculated from the timestamp, but given that the
* callers of this function already have the year information accessible from
* the datetime struct, it is taken as an additional parameter to reduce
* unnecessary calculation.
* */
static _ttinfo *
find_tzrule_ttinfo(_tzrule *rule, int64_t ts, unsigned char fold, int year)
{
if (rule->std_only) {
return &(rule->std);
}
int64_t start, end;
uint8_t isdst;
tzrule_transitions(rule, year, &start, &end);
// With fold = 0, the period (denominated in local time) with the smaller
// offset starts at the end of the gap and ends at the end of the fold;
// with fold = 1, it runs from the start of the gap to the beginning of the
// fold.
//
// So in order to determine the DST boundaries we need to know both the
// fold and whether DST is positive or negative (rare), and it turns out
// that this boils down to fold XOR is_positive.
if (fold == (rule->dst_diff >= 0)) {
end -= rule->dst_diff;
}
else {
start += rule->dst_diff;
}
if (start < end) {
isdst = (ts >= start) && (ts < end);
}
else {
isdst = (ts < end) || (ts >= start);
}
if (isdst) {
return &(rule->dst);
}
else {
return &(rule->std);
}
}
/* Calculate the ttinfo and fold that applies for a _tzrule at an epoch time.
*
* This function can determine the _ttinfo that applies at a given epoch time,
* (analogous to trans_list_utc), and whether or not the datetime is in a fold.
* This is to be used in the .fromutc() function.
*
* The year is technically a redundant parameter, because it can be calculated
* from the timestamp, but all callers of this function should have the year
* in the datetime struct anyway, so taking it as a parameter saves unnecessary
* calculation.
**/
static _ttinfo *
find_tzrule_ttinfo_fromutc(_tzrule *rule, int64_t ts, int year,
unsigned char *fold)
{
if (rule->std_only) {
*fold = 0;
return &(rule->std);
}
int64_t start, end;
uint8_t isdst;
tzrule_transitions(rule, year, &start, &end);
start -= rule->std.utcoff_seconds;
end -= rule->dst.utcoff_seconds;
if (start < end) {
isdst = (ts >= start) && (ts < end);
}
else {
isdst = (ts < end) || (ts >= start);
}
// For positive DST, the ambiguous period is one dst_diff after the end of
// DST; for negative DST, the ambiguous period is one dst_diff before the
// start of DST.
int64_t ambig_start, ambig_end;
if (rule->dst_diff > 0) {
ambig_start = end;
ambig_end = end + rule->dst_diff;
}
else {
ambig_start = start;
ambig_end = start - rule->dst_diff;
}
*fold = (ts >= ambig_start) && (ts < ambig_end);
if (isdst) {
return &(rule->dst);
}
else {
return &(rule->std);
}
}
/* Parse a TZ string in the format specified by the POSIX standard:
*
* std offset[dst[offset],start[/time],end[/time]]
*
* std and dst must be 3 or more characters long and must not contain a
* leading colon, embedded digits, commas, nor a plus or minus signs; The
* spaces between "std" and "offset" are only for display and are not actually
* present in the string.
*
* The format of the offset is ``[+|-]hh[:mm[:ss]]``
*
* See the POSIX.1 spec: IEE Std 1003.1-2018 §8.3:
*
* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html
*/
static int
parse_tz_str(zoneinfo_state *state, PyObject *tz_str_obj, _tzrule *out)
{
PyObject *std_abbr = NULL;
PyObject *dst_abbr = NULL;
TransitionRuleType *start = NULL;
TransitionRuleType *end = NULL;
// Initialize offsets to invalid value (> 24 hours)
long std_offset = 1 << 20;
long dst_offset = 1 << 20;
const char *tz_str = PyBytes_AsString(tz_str_obj);
if (tz_str == NULL) {
return -1;
}
const char *p = tz_str;
// Read the `std` abbreviation, which must be at least 3 characters long.
if (parse_abbr(&p, &std_abbr)) {
if (!PyErr_Occurred()) {
PyErr_Format(PyExc_ValueError, "Invalid STD format in %R", tz_str_obj);
}
goto error;
}
// Now read the STD offset, which is required
if (parse_tz_delta(&p, &std_offset)) {
PyErr_Format(PyExc_ValueError, "Invalid STD offset in %R", tz_str_obj);
goto error;
}
// If the string ends here, there is no DST, otherwise we must parse the
// DST abbreviation and start and end dates and times.
if (*p == '\0') {
goto complete;
}
if (parse_abbr(&p, &dst_abbr)) {
if (!PyErr_Occurred()) {
PyErr_Format(PyExc_ValueError, "Invalid DST format in %R", tz_str_obj);
}
goto error;
}
if (*p == ',') {
// From the POSIX standard:
//
// If no offset follows dst, the alternative time is assumed to be one
// hour ahead of standard time.
dst_offset = std_offset + 3600;
}
else {
if (parse_tz_delta(&p, &dst_offset)) {
PyErr_Format(PyExc_ValueError, "Invalid DST offset in %R",
tz_str_obj);
goto error;
}
}
TransitionRuleType **transitions[2] = {&start, &end};
for (size_t i = 0; i < 2; ++i) {
if (*p != ',') {
PyErr_Format(PyExc_ValueError,
"Missing transition rules in TZ string: %R",
tz_str_obj);
goto error;
}
p++;
if (parse_transition_rule(&p, transitions[i])) {
PyErr_Format(PyExc_ValueError,
"Malformed transition rule in TZ string: %R",
tz_str_obj);
goto error;
}
}
if (*p != '\0') {
PyErr_Format(PyExc_ValueError,
"Extraneous characters at end of TZ string: %R",
tz_str_obj);
goto error;
}
complete:
build_tzrule(state, std_abbr, dst_abbr, std_offset, dst_offset,
start, end, out);
Py_DECREF(std_abbr);
Py_XDECREF(dst_abbr);
return 0;
error:
Py_XDECREF(std_abbr);
if (dst_abbr != NULL && dst_abbr != Py_None) {
Py_DECREF(dst_abbr);
}
if (start != NULL) {
PyMem_Free(start);
}
if (end != NULL) {
PyMem_Free(end);
}
return -1;
}
static int
parse_digits(const char **p, int min, int max, int *value)
{
assert(max <= 3);
*value = 0;
for (int i = 0; i < max; i++, (*p)++) {
if (!Py_ISDIGIT(**p)) {
return (i < min) ? -1 : 0;
}
*value *= 10;
*value += (**p) - '0';
}
return 0;
}
/* Parse the STD and DST abbreviations from a TZ string. */
static int
parse_abbr(const char **p, PyObject **abbr)
{
const char *ptr = *p;
const char *str_start;
const char *str_end;
if (*ptr == '<') {
char buff;
ptr++;
str_start = ptr;
while ((buff = *ptr) != '>') {
// From the POSIX standard:
//
// In the quoted form, the first character shall be the less-than
// ( '<' ) character and the last character shall be the
// greater-than ( '>' ) character. All characters between these
// quoting characters shall be alphanumeric characters from the
// portable character set in the current locale, the plus-sign (
// '+' ) character, or the minus-sign ( '-' ) character. The std
// and dst fields in this case shall not include the quoting
// characters.
if (!Py_ISALPHA(buff) && !Py_ISDIGIT(buff) && buff != '+' &&
buff != '-') {
return -1;
}
ptr++;
}
str_end = ptr;
ptr++;
}
else {
str_start = ptr;
// From the POSIX standard:
//
// In the unquoted form, all characters in these fields shall be
// alphabetic characters from the portable character set in the
// current locale.
while (Py_ISALPHA(*ptr)) {
ptr++;
}
str_end = ptr;
if (str_end == str_start) {
return -1;
}
}
*abbr = PyUnicode_FromStringAndSize(str_start, str_end - str_start);
if (*abbr == NULL) {
return -1;
}
*p = ptr;
return 0;
}
/* Parse a UTC offset from a TZ str. */
static int
parse_tz_delta(const char **p, long *total_seconds)
{
// From the POSIX spec:
//
// Indicates the value added to the local time to arrive at Coordinated
// Universal Time. The offset has the form:
//
// hh[:mm[:ss]]
//
// One or more digits may be used; the value is always interpreted as a
// decimal number.
//
// The POSIX spec says that the values for `hour` must be between 0 and 24
// hours, but RFC 8536 §3.3.1 specifies that the hours part of the
// transition times may be signed and range from -167 to 167.
int hours = 0;
int minutes = 0;
int seconds = 0;
if (parse_transition_time(p, &hours, &minutes, &seconds)) {
return -1;
}
if (hours > 24 || hours < -24) {
return -1;
}
// Negative numbers correspond to *positive* offsets, from the spec:
//
// If preceded by a '-', the timezone shall be east of the Prime
// Meridian; otherwise, it shall be west (which may be indicated by
// an optional preceding '+' ).
*total_seconds = -((hours * 3600L) + (minutes * 60) + seconds);
return 0;
}
/* Parse the date portion of a transition rule. */
static int
parse_transition_rule(const char **p, TransitionRuleType **out)
{
// The full transition rule indicates when to change back and forth between
// STD and DST, and has the form:
//
// date[/time],date[/time]
//
// This function parses an individual date[/time] section, and returns
// the number of characters that contributed to the transition rule. This
// does not include the ',' at the end of the first rule.
//
// The POSIX spec states that if *time* is not given, the default is 02:00.
const char *ptr = *p;
int hour = 2;
int minute = 0;
int second = 0;
// Rules come in one of three flavors:
//
// 1. Jn: Julian day n, with no leap days.
// 2. n: Day of year (0-based, with leap days)
// 3. Mm.n.d: Specifying by month, week and day-of-week.
if (*ptr == 'M') {
int month, week, day;
ptr++;
if (parse_digits(&ptr, 1, 2, &month)) {
return -1;
}
if (*ptr++ != '.') {
return -1;
}
if (parse_digits(&ptr, 1, 1, &week)) {
return -1;
}
if (*ptr++ != '.') {
return -1;
}
if (parse_digits(&ptr, 1, 1, &day)) {
return -1;
}
if (*ptr == '/') {
ptr++;
if (parse_transition_time(&ptr, &hour, &minute, &second)) {
return -1;
}
}
CalendarRule *rv = PyMem_Calloc(1, sizeof(CalendarRule));
if (rv == NULL) {
return -1;
}
if (calendarrule_new(month, week, day, hour, minute, second, rv)) {
PyMem_Free(rv);
return -1;
}
*out = (TransitionRuleType *)rv;
}
else {
int julian = 0;
int day = 0;
if (*ptr == 'J') {
julian = 1;
ptr++;
}
if (parse_digits(&ptr, 1, 3, &day)) {
return -1;
}
if (*ptr == '/') {
ptr++;
if (parse_transition_time(&ptr, &hour, &minute, &second)) {
return -1;
}
}
DayRule *rv = PyMem_Calloc(1, sizeof(DayRule));
if (rv == NULL) {
return -1;
}
if (dayrule_new(julian, day, hour, minute, second, rv)) {
PyMem_Free(rv);
return -1;
}
*out = (TransitionRuleType *)rv;
}
*p = ptr;
return 0;
}
/* Parse the time portion of a transition rule (e.g. following an /) */
static int
parse_transition_time(const char **p, int *hour, int *minute, int *second)
{
// From the spec:
//
// The time has the same format as offset except that no leading sign
// ( '-' or '+' ) is allowed.
//
// The format for the offset is:
//
// h[h][:mm[:ss]]
//
// RFC 8536 also allows transition times to be signed and to range from
// -167 to +167.
const char *ptr = *p;
int sign = 1;
if (*ptr == '-' || *ptr == '+') {
if (*ptr == '-') {
sign = -1;
}
ptr++;
}
// The hour can be 1 to 3 numeric characters
if (parse_digits(&ptr, 1, 3, hour)) {
return -1;
}
*hour *= sign;
// Minutes and seconds always of the format ":dd"
if (*ptr == ':') {
ptr++;
if (parse_digits(&ptr, 2, 2, minute)) {
return -1;
}
*minute *= sign;
if (*ptr == ':') {
ptr++;
if (parse_digits(&ptr, 2, 2, second)) {
return -1;
}
*second *= sign;
}
}
*p = ptr;
return 0;
}
/* Constructor for a _tzrule.
*
* If `dst_abbr` is NULL, this will construct an "STD-only" _tzrule, in which
* case `dst_offset` will be ignored and `start` and `end` are expected to be
* NULL as well.
*
* Returns 0 on success.
*/
static int
build_tzrule(zoneinfo_state *state, PyObject *std_abbr, PyObject *dst_abbr,
long std_offset, long dst_offset, TransitionRuleType *start,
TransitionRuleType *end, _tzrule *out)
{
_tzrule rv = {{0}};
rv.start = start;
rv.end = end;
if (build_ttinfo(state, std_offset, 0, std_abbr, &rv.std)) {
goto error;
}
if (dst_abbr != NULL) {
rv.dst_diff = dst_offset - std_offset;
if (build_ttinfo(state, dst_offset, rv.dst_diff, dst_abbr, &rv.dst)) {
goto error;
}
}
else {
rv.std_only = 1;
}
*out = rv;
return 0;
error:
xdecref_ttinfo(&rv.std);
xdecref_ttinfo(&rv.dst);
return -1;
}
/* Destructor for _tzrule. */
static void
free_tzrule(_tzrule *tzrule)
{
xdecref_ttinfo(&(tzrule->std));
if (!tzrule->std_only) {
xdecref_ttinfo(&(tzrule->dst));
}
if (tzrule->start != NULL) {
PyMem_Free(tzrule->start);
}
if (tzrule->end != NULL) {
PyMem_Free(tzrule->end);
}
}
/* Calculate DST offsets from transitions and UTC offsets
*
* This is necessary because each C `ttinfo` only contains the UTC offset,
* time zone abbreviation and an isdst boolean - it does not include the
* amount of the DST offset, but we need the amount for the dst() function.
*
* Thus function uses heuristics to infer what the offset should be, so it
* is not guaranteed that this will work for all zones. If we cannot assign
* a value for a given DST offset, we'll assume it's 1H rather than 0H, so
* bool(dt.dst()) will always match ttinfo.isdst.
*/
static void
utcoff_to_dstoff(size_t *trans_idx, long *utcoffs, long *dstoffs,
unsigned char *isdsts, size_t num_transitions,
size_t num_ttinfos)
{
size_t dst_count = 0;
size_t dst_found = 0;
for (size_t i = 0; i < num_ttinfos; ++i) {
dst_count++;
}
for (size_t i = 1; i < num_transitions; ++i) {
if (dst_count == dst_found) {
break;
}
size_t idx = trans_idx[i];
size_t comp_idx = trans_idx[i - 1];
// Only look at DST offsets that have nto been assigned already
if (!isdsts[idx] || dstoffs[idx] != 0) {
continue;
}
long dstoff = 0;
long utcoff = utcoffs[idx];
if (!isdsts[comp_idx]) {
dstoff = utcoff - utcoffs[comp_idx];
}
if (!dstoff && idx < (num_ttinfos - 1)) {
comp_idx = trans_idx[i + 1];
// If the following transition is also DST and we couldn't find
// the DST offset by this point, we're going to have to skip it
// and hope this transition gets assigned later
if (isdsts[comp_idx]) {
continue;
}
dstoff = utcoff - utcoffs[comp_idx];
}
if (dstoff) {
dst_found++;
dstoffs[idx] = dstoff;
}
}
if (dst_found < dst_count) {
// If there are time zones we didn't find a value for, we'll end up
// with dstoff = 0 for something where isdst=1. This is obviously
// wrong — one hour will be a much better guess than 0.
for (size_t idx = 0; idx < num_ttinfos; ++idx) {
if (isdsts[idx] && !dstoffs[idx]) {
dstoffs[idx] = 3600;
}
}
}
}
#define _swap(x, y, buffer) \
buffer = x; \
x = y; \
y = buffer;
/* Calculate transitions in local time from UTC time and offsets.
*
* We want to know when each transition occurs, denominated in the number of
* nominal wall-time seconds between 1970-01-01T00:00:00 and the transition in
* *local time* (note: this is *not* equivalent to the output of
* datetime.timestamp, which is the total number of seconds actual elapsed
* since 1970-01-01T00:00:00Z in UTC).
*
* This is an ambiguous question because "local time" can be ambiguous — but it
* is disambiguated by the `fold` parameter, so we allocate two arrays:
*
* trans_local[0]: The wall-time transitions for fold=0
* trans_local[1]: The wall-time transitions for fold=1
*
* This returns 0 on success and a negative number of failure. The trans_local
* arrays must be freed if they are not NULL.
*/
static int
ts_to_local(size_t *trans_idx, int64_t *trans_utc, long *utcoff,
int64_t *trans_local[2], size_t num_ttinfos,
size_t num_transitions)
{
if (num_transitions == 0) {
return 0;
}
// Copy the UTC transitions into each array to be modified in place later
for (size_t i = 0; i < 2; ++i) {
trans_local[i] = PyMem_Malloc(num_transitions * sizeof(int64_t));
if (trans_local[i] == NULL) {
return -1;
}
memcpy(trans_local[i], trans_utc, num_transitions * sizeof(int64_t));
}
int64_t offset_0, offset_1, buff;
if (num_ttinfos > 1) {
offset_0 = utcoff[0];
offset_1 = utcoff[trans_idx[0]];
if (offset_1 > offset_0) {
_swap(offset_0, offset_1, buff);
}
}
else {
offset_0 = utcoff[0];
offset_1 = utcoff[0];
}
trans_local[0][0] += offset_0;
trans_local[1][0] += offset_1;
for (size_t i = 1; i < num_transitions; ++i) {
offset_0 = utcoff[trans_idx[i - 1]];
offset_1 = utcoff[trans_idx[i]];
if (offset_1 > offset_0) {
_swap(offset_1, offset_0, buff);
}
trans_local[0][i] += offset_0;
trans_local[1][i] += offset_1;
}
return 0;
}
/* Simple bisect_right binary search implementation */
static size_t
_bisect(const int64_t value, const int64_t *arr, size_t size)
{
size_t lo = 0;
size_t hi = size;
size_t m;
while (lo < hi) {
m = (lo + hi) / 2;
if (arr[m] > value) {
hi = m;
}
else {
lo = m + 1;
}
}
return hi;
}
/* Find the ttinfo rules that apply at a given local datetime. */
static _ttinfo *
find_ttinfo(zoneinfo_state *state, PyZoneInfo_ZoneInfo *self, PyObject *dt)
{
// datetime.time has a .tzinfo attribute that passes None as the dt
// argument; it only really has meaning for fixed-offset zones.
if (dt == Py_None) {
if (self->fixed_offset) {
return &(self->tzrule_after.std);
}
else {
return &(state->NO_TTINFO);
}
}
int64_t ts;
if (get_local_timestamp(dt, &ts)) {
return NULL;
}
unsigned char fold = PyDateTime_DATE_GET_FOLD(dt);
assert(fold < 2);
int64_t *local_transitions = self->trans_list_wall[fold];
size_t num_trans = self->num_transitions;
if (num_trans && ts < local_transitions[0]) {
return self->ttinfo_before;
}
else if (!num_trans || ts > local_transitions[self->num_transitions - 1]) {
return find_tzrule_ttinfo(&(self->tzrule_after), ts, fold,
PyDateTime_GET_YEAR(dt));
}
else {
size_t idx = _bisect(ts, local_transitions, self->num_transitions) - 1;
assert(idx < self->num_transitions);
return self->trans_ttinfos[idx];
}
}
static int
is_leap_year(int year)
{
const unsigned int ayear = (unsigned int)year;
return ayear % 4 == 0 && (ayear % 100 != 0 || ayear % 400 == 0);
}
/* Calculates ordinal datetime from year, month and day. */
static int
ymd_to_ord(int y, int m, int d)
{
y -= 1;
int days_before_year = (y * 365) + (y / 4) - (y / 100) + (y / 400);
int yearday = DAYS_BEFORE_MONTH[m];
if (m > 2 && is_leap_year(y + 1)) {
yearday += 1;
}
return days_before_year + yearday + d;
}
/* Calculate the number of seconds since 1970-01-01 in local time.
*
* This gets a datetime in the same "units" as self->trans_list_wall so that we
* can easily determine which transitions a datetime falls between. See the
* comment above ts_to_local for more information.
* */
static int
get_local_timestamp(PyObject *dt, int64_t *local_ts)
{
assert(local_ts != NULL);
int hour, minute, second;
int ord;
if (PyDateTime_CheckExact(dt)) {
int y = PyDateTime_GET_YEAR(dt);
int m = PyDateTime_GET_MONTH(dt);
int d = PyDateTime_GET_DAY(dt);
hour = PyDateTime_DATE_GET_HOUR(dt);
minute = PyDateTime_DATE_GET_MINUTE(dt);
second = PyDateTime_DATE_GET_SECOND(dt);
ord = ymd_to_ord(y, m, d);
}
else {
PyObject *num = PyObject_CallMethod(dt, "toordinal", NULL);
if (num == NULL) {
return -1;
}
ord = PyLong_AsLong(num);
Py_DECREF(num);
if (ord == -1 && PyErr_Occurred()) {
return -1;
}
num = PyObject_GetAttrString(dt, "hour");
if (num == NULL) {
return -1;
}
hour = PyLong_AsLong(num);
Py_DECREF(num);
if (hour == -1) {
return -1;
}
num = PyObject_GetAttrString(dt, "minute");
if (num == NULL) {
return -1;
}
minute = PyLong_AsLong(num);
Py_DECREF(num);
if (minute == -1) {
return -1;
}
num = PyObject_GetAttrString(dt, "second");
if (num == NULL) {
return -1;
}
second = PyLong_AsLong(num);
Py_DECREF(num);
if (second == -1) {
return -1;
}
}
*local_ts = (int64_t)(ord - EPOCHORDINAL) * 86400L +
(int64_t)(hour * 3600L + minute * 60 + second);
return 0;
}
/////
// Functions for cache handling
/* Constructor for StrongCacheNode
*
* This function doesn't set MemoryError if PyMem_Malloc fails,
* as the cache intentionally doesn't propagate exceptions
* and fails silently if error occurs.
*/
static StrongCacheNode *
strong_cache_node_new(PyObject *key, PyObject *zone)
{
StrongCacheNode *node = PyMem_Malloc(sizeof(StrongCacheNode));
if (node == NULL) {
return NULL;
}
node->next = NULL;
node->prev = NULL;
node->key = Py_NewRef(key);
node->zone = Py_NewRef(zone);
return node;
}
/* Destructor for StrongCacheNode */
void
strong_cache_node_free(StrongCacheNode *node)
{
Py_XDECREF(node->key);
Py_XDECREF(node->zone);
PyMem_Free(node);
}
/* Frees all nodes at or after a specified root in the strong cache.
*
* This can be used on the root node to free the entire cache or it can be used
* to clear all nodes that have been expired (which, if everything is going
* right, will actually only be 1 node at a time).
*/
void
strong_cache_free(StrongCacheNode *root)
{
StrongCacheNode *node = root;
StrongCacheNode *next_node;
while (node != NULL) {
next_node = node->next;
strong_cache_node_free(node);
node = next_node;
}
}
/* Removes a node from the cache and update its neighbors.
*
* This is used both when ejecting a node from the cache and when moving it to
* the front of the cache.
*/
static void
remove_from_strong_cache(zoneinfo_state *state, StrongCacheNode *node)
{
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(state->ZoneInfoType);
if (state->ZONEINFO_STRONG_CACHE == node) {
state->ZONEINFO_STRONG_CACHE = node->next;
}
if (node->prev != NULL) {
node->prev->next = node->next;
}
if (node->next != NULL) {
node->next->prev = node->prev;
}
node->next = NULL;
node->prev = NULL;
}
/* Retrieves the node associated with a key, if it exists.
*
* This traverses the strong cache until it finds a matching key and returns a
* pointer to the relevant node if found. Returns NULL if no node is found.
*
* root may be NULL, indicating an empty cache.
*/
static StrongCacheNode *
find_in_strong_cache(const StrongCacheNode *const root, PyObject *const key)
{
const StrongCacheNode *node = root;
while (node != NULL) {
int rv = PyObject_RichCompareBool(key, node->key, Py_EQ);
if (rv < 0) {
return NULL;
}
if (rv) {
return (StrongCacheNode *)node;
}
node = node->next;
}
return NULL;
}
/* Ejects a given key from the class's strong cache, if applicable.
*
* This function is used to enable the per-key functionality in clear_cache.
*/
static int
eject_from_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *key)
{
if (type != state->ZoneInfoType) {
return 0;
}
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(state->ZoneInfoType);
StrongCacheNode *cache = state->ZONEINFO_STRONG_CACHE;
StrongCacheNode *node = find_in_strong_cache(cache, key);
if (node != NULL) {
remove_from_strong_cache(state, node);
strong_cache_node_free(node);
}
else if (PyErr_Occurred()) {
return -1;
}
return 0;
}
/* Moves a node to the front of the LRU cache.
*
* The strong cache is an LRU cache, so whenever a given node is accessed, if
* it is not at the front of the cache, it needs to be moved there.
*/
static void
move_strong_cache_node_to_front(zoneinfo_state *state, StrongCacheNode **root,
StrongCacheNode *node)
{
StrongCacheNode *root_p = *root;
if (root_p == node) {
return;
}
remove_from_strong_cache(state, node);
node->prev = NULL;
node->next = root_p;
if (root_p != NULL) {
root_p->prev = node;
}
*root = node;
}
/* Retrieves a ZoneInfo from the strong cache if it's present.
*
* This function finds the ZoneInfo by key and if found will move the node to
* the front of the LRU cache and return a new reference to it. It returns NULL
* if the key is not in the cache.
*
* The strong cache is currently only implemented for the base class, so this
* always returns a cache miss for subclasses.
*/
static PyObject *
zone_from_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *const key)
{
if (type != state->ZoneInfoType) {
return NULL; // Strong cache currently only implemented for base class
}
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(state->ZoneInfoType);
StrongCacheNode *cache = state->ZONEINFO_STRONG_CACHE;
StrongCacheNode *node = find_in_strong_cache(cache, key);
if (node != NULL) {
StrongCacheNode **root = &(state->ZONEINFO_STRONG_CACHE);
move_strong_cache_node_to_front(state, root, node);
return Py_NewRef(node->zone);
}
return NULL; // Cache miss
}
/* Inserts a new key into the strong LRU cache.
*
* This function is only to be used after a cache miss — it creates a new node
* at the front of the cache and ejects any stale entries (keeping the size of
* the cache to at most ZONEINFO_STRONG_CACHE_MAX_SIZE).
*/
static void
update_strong_cache(zoneinfo_state *state, const PyTypeObject *const type,
PyObject *key, PyObject *zone)
{
if (type != state->ZoneInfoType) {
return;
}
_Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(state->ZoneInfoType);
StrongCacheNode *new_node = strong_cache_node_new(key, zone);
if (new_node == NULL) {
return;
}
StrongCacheNode **root = &(state->ZONEINFO_STRONG_CACHE);
move_strong_cache_node_to_front(state, root, new_node);
StrongCacheNode *node = new_node->next;
for (size_t i = 1; i < ZONEINFO_STRONG_CACHE_MAX_SIZE; ++i) {
if (node == NULL) {
return;
}
node = node->next;
}
// Everything beyond this point needs to be freed
if (node != NULL) {
if (node->prev != NULL) {
node->prev->next = NULL;
}
strong_cache_free(node);
}
}
/* Clears all entries into a type's strong cache.
*
* Because the strong cache is not implemented for subclasses, this is a no-op
* for everything except the base class.
*/
void
clear_strong_cache(zoneinfo_state *state, const PyTypeObject *const type)
{
if (type != state->ZoneInfoType) {
return;
}
strong_cache_free(state->ZONEINFO_STRONG_CACHE);
state->ZONEINFO_STRONG_CACHE = NULL;
}
static PyObject *
new_weak_cache(void)
{
PyObject *WeakValueDictionary =
_PyImport_GetModuleAttrString("weakref", "WeakValueDictionary");
if (WeakValueDictionary == NULL) {
return NULL;
}
PyObject *weak_cache = PyObject_CallNoArgs(WeakValueDictionary);
Py_DECREF(WeakValueDictionary);
return weak_cache;
}
// This function is not idempotent and must be called on a new module object.
static int
initialize_caches(zoneinfo_state *state)
{
state->TIMEDELTA_CACHE = PyDict_New();
if (state->TIMEDELTA_CACHE == NULL) {
return -1;
}
state->ZONEINFO_WEAK_CACHE = new_weak_cache();
if (state->ZONEINFO_WEAK_CACHE == NULL) {
return -1;
}
return 0;
}
static PyObject *
zoneinfo_init_subclass(PyTypeObject *cls, PyObject *args, PyObject **kwargs)
{
PyObject *weak_cache = new_weak_cache();
if (weak_cache == NULL) {
return NULL;
}
if (PyObject_SetAttrString((PyObject *)cls, "_weak_cache",
weak_cache) < 0) {
Py_DECREF(weak_cache);
return NULL;
}
Py_DECREF(weak_cache);
Py_RETURN_NONE;
}
/////
// Specify the ZoneInfo type
static PyMethodDef zoneinfo_methods[] = {
ZONEINFO_ZONEINFO_CLEAR_CACHE_METHODDEF
ZONEINFO_ZONEINFO_NO_CACHE_METHODDEF
ZONEINFO_ZONEINFO_FROM_FILE_METHODDEF
ZONEINFO_ZONEINFO_UTCOFFSET_METHODDEF
ZONEINFO_ZONEINFO_DST_METHODDEF
ZONEINFO_ZONEINFO_TZNAME_METHODDEF
{"fromutc", (PyCFunction)zoneinfo_fromutc, METH_O,
PyDoc_STR("Given a datetime with local time in UTC, retrieve an adjusted "
"datetime in local time.")},
{"__reduce__", (PyCFunction)zoneinfo_reduce, METH_NOARGS,
PyDoc_STR("Function for serialization with the pickle protocol.")},
ZONEINFO_ZONEINFO__UNPICKLE_METHODDEF
{"__init_subclass__", (PyCFunction)(void (*)(void))zoneinfo_init_subclass,
METH_VARARGS | METH_KEYWORDS | METH_CLASS,
PyDoc_STR("Function to initialize subclasses.")},
{NULL} /* Sentinel */
};
static PyMemberDef zoneinfo_members[] = {
{.name = "key",
.offset = offsetof(PyZoneInfo_ZoneInfo, key),
.type = Py_T_OBJECT_EX,
.flags = Py_READONLY,
.doc = NULL},
{.name = "__weaklistoffset__",
.offset = offsetof(PyZoneInfo_ZoneInfo, weakreflist),
.type = Py_T_PYSSIZET,
.flags = Py_READONLY},
{NULL}, /* Sentinel */
};
static PyType_Slot zoneinfo_slots[] = {
{Py_tp_repr, zoneinfo_repr},
{Py_tp_str, zoneinfo_str},
{Py_tp_getattro, PyObject_GenericGetAttr},
{Py_tp_methods, zoneinfo_methods},
{Py_tp_members, zoneinfo_members},
{Py_tp_new, zoneinfo_ZoneInfo},
{Py_tp_dealloc, zoneinfo_dealloc},
{Py_tp_traverse, zoneinfo_traverse},
{Py_tp_clear, zoneinfo_clear},
{0, NULL},
};
static PyType_Spec zoneinfo_spec = {
.name = "zoneinfo.ZoneInfo",
.basicsize = sizeof(PyZoneInfo_ZoneInfo),
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_IMMUTABLETYPE),
.slots = zoneinfo_slots,
};
/////
// Specify the _zoneinfo module
static PyMethodDef module_methods[] = {{NULL, NULL}};
static int
module_traverse(PyObject *mod, visitproc visit, void *arg)
{
zoneinfo_state *state = zoneinfo_get_state(mod);
Py_VISIT(state->ZoneInfoType);
Py_VISIT(state->io_open);
Py_VISIT(state->_tzpath_find_tzfile);
Py_VISIT(state->_common_mod);
Py_VISIT(state->TIMEDELTA_CACHE);
Py_VISIT(state->ZONEINFO_WEAK_CACHE);
StrongCacheNode *node = state->ZONEINFO_STRONG_CACHE;
while (node != NULL) {
StrongCacheNode *next = node->next;
Py_VISIT(node->key);
Py_VISIT(node->zone);
node = next;
}
Py_VISIT(state->NO_TTINFO.utcoff);
Py_VISIT(state->NO_TTINFO.dstoff);
Py_VISIT(state->NO_TTINFO.tzname);
return 0;
}
static int
module_clear(PyObject *mod)
{
zoneinfo_state *state = zoneinfo_get_state(mod);
Py_CLEAR(state->ZoneInfoType);
Py_CLEAR(state->io_open);
Py_CLEAR(state->_tzpath_find_tzfile);
Py_CLEAR(state->_common_mod);
Py_CLEAR(state->TIMEDELTA_CACHE);
Py_CLEAR(state->ZONEINFO_WEAK_CACHE);
clear_strong_cache(state, state->ZoneInfoType);
Py_CLEAR(state->NO_TTINFO.utcoff);
Py_CLEAR(state->NO_TTINFO.dstoff);
Py_CLEAR(state->NO_TTINFO.tzname);
return 0;
}
static void
module_free(void *mod)
{
(void)module_clear((PyObject *)mod);
}
static int
zoneinfomodule_exec(PyObject *m)
{
PyDateTime_IMPORT;
if (PyDateTimeAPI == NULL) {
goto error;
}
zoneinfo_state *state = zoneinfo_get_state(m);
PyObject *base = (PyObject *)PyDateTimeAPI->TZInfoType;
state->ZoneInfoType = (PyTypeObject *)PyType_FromModuleAndSpec(m,
&zoneinfo_spec, base);
if (state->ZoneInfoType == NULL) {
goto error;
}
int rc = PyModule_AddObjectRef(m, "ZoneInfo",
(PyObject *)state->ZoneInfoType);
if (rc < 0) {
goto error;
}
/* Populate imports */
state->_tzpath_find_tzfile =
_PyImport_GetModuleAttrString("zoneinfo._tzpath", "find_tzfile");
if (state->_tzpath_find_tzfile == NULL) {
goto error;
}
state->io_open = _PyImport_GetModuleAttrString("io", "open");
if (state->io_open == NULL) {
goto error;
}
state->_common_mod = PyImport_ImportModule("zoneinfo._common");
if (state->_common_mod == NULL) {
goto error;
}
if (state->NO_TTINFO.utcoff == NULL) {
state->NO_TTINFO.utcoff = Py_NewRef(Py_None);
state->NO_TTINFO.dstoff = Py_NewRef(Py_None);
state->NO_TTINFO.tzname = Py_NewRef(Py_None);
}
if (initialize_caches(state)) {
goto error;
}
return 0;
error:
return -1;
}
static PyModuleDef_Slot zoneinfomodule_slots[] = {
{Py_mod_exec, zoneinfomodule_exec},
{Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
{Py_mod_gil, Py_MOD_GIL_NOT_USED},
{0, NULL},
};
static struct PyModuleDef zoneinfomodule = {
.m_base = PyModuleDef_HEAD_INIT,
.m_name = "_zoneinfo",
.m_doc = "C implementation of the zoneinfo module",
.m_size = sizeof(zoneinfo_state),
.m_methods = module_methods,
.m_slots = zoneinfomodule_slots,
.m_traverse = module_traverse,
.m_clear = module_clear,
.m_free = module_free,
};
PyMODINIT_FUNC
PyInit__zoneinfo(void)
{
return PyModuleDef_Init(&zoneinfomodule);
}
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