diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py index eaee837f10e..bf04ac541e6 100644 --- a/Lib/sysconfig.py +++ b/Lib/sysconfig.py @@ -546,6 +546,7 @@ def get_config_vars(*args): if os.name == 'nt': _init_non_posix(_CONFIG_VARS) + _CONFIG_VARS['TZPATH'] = '' if os.name == 'posix': _init_posix(_CONFIG_VARS) # For backward compatibility, see issue19555 diff --git a/Lib/zoneinfo/__init__.py b/Lib/zoneinfo/__init__.py new file mode 100644 index 00000000000..81a2d5ea97b --- /dev/null +++ b/Lib/zoneinfo/__init__.py @@ -0,0 +1,29 @@ +__all__ = [ + "ZoneInfo", + "reset_tzpath", + "TZPATH", + "ZoneInfoNotFoundError", + "InvalidTZPathWarning", +] + +from . import _tzpath +from ._common import ZoneInfoNotFoundError + +try: + from _zoneinfo import ZoneInfo +except ImportError: # pragma: nocover + from ._zoneinfo import ZoneInfo + +reset_tzpath = _tzpath.reset_tzpath +InvalidTZPathWarning = _tzpath.InvalidTZPathWarning + + +def __getattr__(name): + if name == "TZPATH": + return _tzpath.TZPATH + else: + raise AttributeError(f"module {__name__!r} has no attribute {name!r}") + + +def __dir__(): + return sorted(list(globals()) + ["TZPATH"]) diff --git a/Lib/zoneinfo/_common.py b/Lib/zoneinfo/_common.py new file mode 100644 index 00000000000..3d35d4f4b46 --- /dev/null +++ b/Lib/zoneinfo/_common.py @@ -0,0 +1,166 @@ +import struct + + +def load_tzdata(key): + import importlib.resources + + components = key.split("/") + package_name = ".".join(["tzdata.zoneinfo"] + components[:-1]) + resource_name = components[-1] + + try: + return importlib.resources.open_binary(package_name, resource_name) + except (ImportError, FileNotFoundError, UnicodeEncodeError): + # There are three types of exception that can be raised that all amount + # to "we cannot find this key": + # + # ImportError: If package_name doesn't exist (e.g. if tzdata is not + # installed, or if there's an error in the folder name like + # Amrica/New_York) + # FileNotFoundError: If resource_name doesn't exist in the package + # (e.g. Europe/Krasnoy) + # UnicodeEncodeError: If package_name or resource_name are not UTF-8, + # such as keys containing a surrogate character. + raise ZoneInfoNotFoundError(f"No time zone found with key {key}") + + +def load_data(fobj): + header = _TZifHeader.from_file(fobj) + + if header.version == 1: + time_size = 4 + time_type = "l" + else: + # Version 2+ has 64-bit integer transition times + time_size = 8 + time_type = "q" + + # Version 2+ also starts with a Version 1 header and data, which + # we need to skip now + skip_bytes = ( + header.timecnt * 5 # Transition times and types + + header.typecnt * 6 # Local time type records + + header.charcnt # Time zone designations + + header.leapcnt * 8 # Leap second records + + header.isstdcnt # Standard/wall indicators + + header.isutcnt # UT/local indicators + ) + + fobj.seek(skip_bytes, 1) + + # Now we need to read the second header, which is not the same + # as the first + header = _TZifHeader.from_file(fobj) + + typecnt = header.typecnt + timecnt = header.timecnt + charcnt = header.charcnt + + # The data portion starts with timecnt transitions and indices + if timecnt: + trans_list_utc = struct.unpack( + f">{timecnt}{time_type}", fobj.read(timecnt * time_size) + ) + trans_idx = struct.unpack(f">{timecnt}B", fobj.read(timecnt)) + else: + trans_list_utc = () + trans_idx = () + + # Read the ttinfo struct, (utoff, isdst, abbrind) + if typecnt: + utcoff, isdst, abbrind = zip( + *(struct.unpack(">lbb", fobj.read(6)) for i in range(typecnt)) + ) + else: + utcoff = () + isdst = () + abbrind = () + + # Now read the abbreviations. They are null-terminated strings, indexed + # not by position in the array but by position in the unsplit + # abbreviation string. I suppose this makes more sense in C, which uses + # null to terminate the strings, but it's inconvenient here... + char_total = 0 + abbr_vals = {} + abbr_chars = fobj.read(charcnt) + + def get_abbr(idx): + # Gets a string starting at idx and running until the next \x00 + # + # We cannot pre-populate abbr_vals by splitting on \x00 because there + # are some zones that use subsets of longer abbreviations, like so: + # + # LMT\x00AHST\x00HDT\x00 + # + # Where the idx to abbr mapping should be: + # + # {0: "LMT", 4: "AHST", 5: "HST", 9: "HDT"} + if idx not in abbr_vals: + span_end = abbr_chars.find(b"\x00", idx) + abbr_vals[idx] = abbr_chars[idx:span_end].decode() + + return abbr_vals[idx] + + abbr = tuple(get_abbr(idx) for idx in abbrind) + + # The remainder of the file consists of leap seconds (currently unused) and + # the standard/wall and ut/local indicators, which are metadata we don't need. + # In version 2 files, we need to skip the unnecessary data to get at the TZ string: + if header.version >= 2: + # Each leap second record has size (time_size + 4) + skip_bytes = header.isutcnt + header.isstdcnt + header.leapcnt * 12 + fobj.seek(skip_bytes, 1) + + c = fobj.read(1) # Should be \n + assert c == b"\n", c + + tz_bytes = b"" + while (c := fobj.read(1)) != b"\n": + tz_bytes += c + + tz_str = tz_bytes + else: + tz_str = None + + return trans_idx, trans_list_utc, utcoff, isdst, abbr, tz_str + + +class _TZifHeader: + __slots__ = [ + "version", + "isutcnt", + "isstdcnt", + "leapcnt", + "timecnt", + "typecnt", + "charcnt", + ] + + def __init__(self, *args): + assert len(self.__slots__) == len(args) + for attr, val in zip(self.__slots__, args): + setattr(self, attr, val) + + @classmethod + def from_file(cls, stream): + # The header starts with a 4-byte "magic" value + if stream.read(4) != b"TZif": + raise ValueError("Invalid TZif file: magic not found") + + _version = stream.read(1) + if _version == b"\x00": + version = 1 + else: + version = int(_version) + stream.read(15) + + args = (version,) + + # Slots are defined in the order that the bytes are arranged + args = args + struct.unpack(">6l", stream.read(24)) + + return cls(*args) + + +class ZoneInfoNotFoundError(KeyError): + """Exception raised when a ZoneInfo key is not found.""" diff --git a/Lib/zoneinfo/_tzpath.py b/Lib/zoneinfo/_tzpath.py new file mode 100644 index 00000000000..8cff0b171bf --- /dev/null +++ b/Lib/zoneinfo/_tzpath.py @@ -0,0 +1,110 @@ +import os +import sys +import sysconfig + + +def reset_tzpath(to=None): + global TZPATH + + tzpaths = to + if tzpaths is not None: + if isinstance(tzpaths, (str, bytes)): + raise TypeError( + f"tzpaths must be a list or tuple, " + + f"not {type(tzpaths)}: {tzpaths!r}" + ) + elif not all(map(os.path.isabs, tzpaths)): + raise ValueError(_get_invalid_paths_message(tzpaths)) + base_tzpath = tzpaths + else: + env_var = os.environ.get("PYTHONTZPATH", None) + if env_var is not None: + base_tzpath = _parse_python_tzpath(env_var) + else: + base_tzpath = _parse_python_tzpath( + sysconfig.get_config_var("TZPATH") + ) + + TZPATH = tuple(base_tzpath) + + +def _parse_python_tzpath(env_var): + if not env_var: + return () + + raw_tzpath = env_var.split(os.pathsep) + new_tzpath = tuple(filter(os.path.isabs, raw_tzpath)) + + # If anything has been filtered out, we will warn about it + if len(new_tzpath) != len(raw_tzpath): + import warnings + + msg = _get_invalid_paths_message(raw_tzpath) + + warnings.warn( + "Invalid paths specified in PYTHONTZPATH environment variable." + + msg, + InvalidTZPathWarning, + ) + + return new_tzpath + + +def _get_invalid_paths_message(tzpaths): + invalid_paths = (path for path in tzpaths if not os.path.isabs(path)) + + prefix = "\n " + indented_str = prefix + prefix.join(invalid_paths) + + return ( + "Paths should be absolute but found the following relative paths:" + + indented_str + ) + + +def find_tzfile(key): + """Retrieve the path to a TZif file from a key.""" + _validate_tzfile_path(key) + for search_path in TZPATH: + filepath = os.path.join(search_path, key) + if os.path.isfile(filepath): + return filepath + + return None + + +_TEST_PATH = os.path.normpath(os.path.join("_", "_"))[:-1] + + +def _validate_tzfile_path(path, _base=_TEST_PATH): + if os.path.isabs(path): + raise ValueError( + f"ZoneInfo keys may not be absolute paths, got: {path}" + ) + + # We only care about the kinds of path normalizations that would change the + # length of the key - e.g. a/../b -> a/b, or a/b/ -> a/b. On Windows, + # normpath will also change from a/b to a\b, but that would still preserve + # the length. + new_path = os.path.normpath(path) + if len(new_path) != len(path): + raise ValueError( + f"ZoneInfo keys must be normalized relative paths, got: {path}" + ) + + resolved = os.path.normpath(os.path.join(_base, new_path)) + if not resolved.startswith(_base): + raise ValueError( + f"ZoneInfo keys must refer to subdirectories of TZPATH, got: {path}" + ) + + +del _TEST_PATH + + +class InvalidTZPathWarning(RuntimeWarning): + """Warning raised if an invalid path is specified in PYTHONTZPATH.""" + + +TZPATH = () +reset_tzpath() diff --git a/Lib/zoneinfo/_zoneinfo.py b/Lib/zoneinfo/_zoneinfo.py new file mode 100644 index 00000000000..69133ae80a4 --- /dev/null +++ b/Lib/zoneinfo/_zoneinfo.py @@ -0,0 +1,755 @@ +import bisect +import calendar +import collections +import functools +import os +import re +import struct +import sys +import weakref +from datetime import datetime, timedelta, timezone, tzinfo + +from . import _common, _tzpath + +EPOCH = datetime(1970, 1, 1) +EPOCHORDINAL = datetime(1970, 1, 1).toordinal() + +# It is relatively expensive to construct new timedelta objects, and in most +# cases we're looking at the same deltas, like integer numbers of hours, etc. +# To improve speed and memory use, we'll keep a dictionary with references +# to the ones we've already used so far. +# +# Loading every time zone in the 2020a version of the time zone database +# requires 447 timedeltas, which requires approximately the amount of space +# that ZoneInfo("America/New_York") with 236 transitions takes up, so we will +# set the cache size to 512 so that in the common case we always get cache +# hits, but specifically crafted ZoneInfo objects don't leak arbitrary amounts +# of memory. +@functools.lru_cache(maxsize=512) +def _load_timedelta(seconds): + return timedelta(seconds=seconds) + + +class ZoneInfo(tzinfo): + _strong_cache_size = 8 + _strong_cache = collections.OrderedDict() + _weak_cache = weakref.WeakValueDictionary() + __module__ = "zoneinfo" + + def __init_subclass__(cls): + cls._strong_cache = collections.OrderedDict() + cls._weak_cache = weakref.WeakValueDictionary() + + def __new__(cls, key): + instance = cls._weak_cache.get(key, None) + if instance is None: + instance = cls._weak_cache.setdefault(key, cls._new_instance(key)) + instance._from_cache = True + + # Update the "strong" cache + cls._strong_cache[key] = cls._strong_cache.pop(key, instance) + + if len(cls._strong_cache) > cls._strong_cache_size: + cls._strong_cache.popitem(last=False) + + return instance + + @classmethod + def no_cache(cls, key): + obj = cls._new_instance(key) + obj._from_cache = False + + return obj + + @classmethod + def _new_instance(cls, key): + obj = super().__new__(cls) + obj._key = key + obj._file_path = obj._find_tzfile(key) + + if obj._file_path is not None: + file_obj = open(obj._file_path, "rb") + else: + file_obj = _common.load_tzdata(key) + + with file_obj as f: + obj._load_file(f) + + return obj + + @classmethod + def from_file(cls, fobj, /, key=None): + obj = super().__new__(cls) + obj._key = key + obj._file_path = None + obj._load_file(fobj) + obj._file_repr = repr(fobj) + + # Disable pickling for objects created from files + obj.__reduce__ = obj._file_reduce + + return obj + + @classmethod + def clear_cache(cls, *, only_keys=None): + if only_keys is not None: + for key in only_keys: + cls._weak_cache.pop(key, None) + cls._strong_cache.pop(key, None) + + else: + cls._weak_cache.clear() + cls._strong_cache.clear() + + @property + def key(self): + return self._key + + def utcoffset(self, dt): + return self._find_trans(dt).utcoff + + def dst(self, dt): + return self._find_trans(dt).dstoff + + def tzname(self, dt): + return self._find_trans(dt).tzname + + def fromutc(self, dt): + """Convert from datetime in UTC to datetime in local time""" + + if not isinstance(dt, datetime): + raise TypeError("fromutc() requires a datetime argument") + if dt.tzinfo is not self: + raise ValueError("dt.tzinfo is not self") + + timestamp = self._get_local_timestamp(dt) + num_trans = len(self._trans_utc) + + if num_trans >= 1 and timestamp < self._trans_utc[0]: + tti = self._tti_before + fold = 0 + elif ( + num_trans == 0 or timestamp > self._trans_utc[-1] + ) and not isinstance(self._tz_after, _ttinfo): + tti, fold = self._tz_after.get_trans_info_fromutc( + timestamp, dt.year + ) + elif num_trans == 0: + tti = self._tz_after + fold = 0 + else: + idx = bisect.bisect_right(self._trans_utc, timestamp) + + if num_trans > 1 and timestamp >= self._trans_utc[1]: + tti_prev, tti = self._ttinfos[idx - 2 : idx] + elif timestamp > self._trans_utc[-1]: + tti_prev = self._ttinfos[-1] + tti = self._tz_after + else: + tti_prev = self._tti_before + tti = self._ttinfos[0] + + # Detect fold + shift = tti_prev.utcoff - tti.utcoff + fold = shift.total_seconds() > timestamp - self._trans_utc[idx - 1] + dt += tti.utcoff + if fold: + return dt.replace(fold=1) + else: + return dt + + def _find_trans(self, dt): + if dt is None: + if self._fixed_offset: + return self._tz_after + else: + return _NO_TTINFO + + ts = self._get_local_timestamp(dt) + + lt = self._trans_local[dt.fold] + + num_trans = len(lt) + + if num_trans and ts < lt[0]: + return self._tti_before + elif not num_trans or ts > lt[-1]: + if isinstance(self._tz_after, _TZStr): + return self._tz_after.get_trans_info(ts, dt.year, dt.fold) + else: + return self._tz_after + else: + # idx is the transition that occurs after this timestamp, so we + # subtract off 1 to get the current ttinfo + idx = bisect.bisect_right(lt, ts) - 1 + assert idx >= 0 + return self._ttinfos[idx] + + def _get_local_timestamp(self, dt): + return ( + (dt.toordinal() - EPOCHORDINAL) * 86400 + + dt.hour * 3600 + + dt.minute * 60 + + dt.second + ) + + def __str__(self): + if self._key is not None: + return f"{self._key}" + else: + return repr(self) + + def __repr__(self): + if self._key is not None: + return f"{self.__class__.__name__}(key={self._key!r})" + else: + return f"{self.__class__.__name__}.from_file({self._file_repr})" + + def __reduce__(self): + return (self.__class__._unpickle, (self._key, self._from_cache)) + + def _file_reduce(self): + import pickle + + raise pickle.PicklingError( + "Cannot pickle a ZoneInfo file created from a file stream." + ) + + @classmethod + def _unpickle(cls, key, from_cache, /): + if from_cache: + return cls(key) + else: + return cls.no_cache(key) + + def _find_tzfile(self, key): + return _tzpath.find_tzfile(key) + + def _load_file(self, fobj): + # Retrieve all the data as it exists in the zoneinfo file + trans_idx, trans_utc, utcoff, isdst, abbr, tz_str = _common.load_data( + fobj + ) + + # Infer the DST offsets (needed for .dst()) from the data + dstoff = self._utcoff_to_dstoff(trans_idx, utcoff, isdst) + + # Convert all the transition times (UTC) into "seconds since 1970-01-01 local time" + trans_local = self._ts_to_local(trans_idx, trans_utc, utcoff) + + # Construct `_ttinfo` objects for each transition in the file + _ttinfo_list = [ + _ttinfo( + _load_timedelta(utcoffset), _load_timedelta(dstoffset), tzname + ) + for utcoffset, dstoffset, tzname in zip(utcoff, dstoff, abbr) + ] + + self._trans_utc = trans_utc + self._trans_local = trans_local + self._ttinfos = [_ttinfo_list[idx] for idx in trans_idx] + + # Find the first non-DST transition + for i in range(len(isdst)): + if not isdst[i]: + self._tti_before = _ttinfo_list[i] + break + else: + if self._ttinfos: + self._tti_before = self._ttinfos[0] + else: + self._tti_before = None + + # Set the "fallback" time zone + if tz_str is not None and tz_str != b"": + self._tz_after = _parse_tz_str(tz_str.decode()) + else: + if not self._ttinfos and not _ttinfo_list: + raise ValueError("No time zone information found.") + + if self._ttinfos: + self._tz_after = self._ttinfos[-1] + else: + self._tz_after = _ttinfo_list[-1] + + # 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 _tz_after is not a _ttinfo, it has transitions that might + # actually 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 _ttinfo_list contains more than one _ttinfo object, the objects + # represent different offsets. + # 3. _ttinfo_list 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 len(_ttinfo_list) > 1 or not isinstance(self._tz_after, _ttinfo): + self._fixed_offset = False + elif not _ttinfo_list: + self._fixed_offset = True + else: + self._fixed_offset = _ttinfo_list[0] == self._tz_after + + @staticmethod + def _utcoff_to_dstoff(trans_idx, utcoffsets, isdsts): + # Now we must transform our ttis and abbrs into `_ttinfo` objects, + # but there is an issue: .dst() must return a timedelta with the + # difference between utcoffset() and the "standard" offset, but + # the "base offset" and "DST offset" are not encoded in the file; + # we can infer what they are from the isdst flag, but it is not + # sufficient to to just look at the last standard offset, because + # occasionally countries will shift both DST offset and base offset. + + typecnt = len(isdsts) + dstoffs = [0] * typecnt # Provisionally assign all to 0. + dst_cnt = sum(isdsts) + dst_found = 0 + + for i in range(1, len(trans_idx)): + if dst_cnt == dst_found: + break + + idx = trans_idx[i] + + dst = isdsts[idx] + + # We're only going to look at daylight saving time + if not dst: + continue + + # Skip any offsets that have already been assigned + if dstoffs[idx] != 0: + continue + + dstoff = 0 + utcoff = utcoffsets[idx] + + comp_idx = trans_idx[i - 1] + + if not isdsts[comp_idx]: + dstoff = utcoff - utcoffsets[comp_idx] + + if not dstoff and idx < (typecnt - 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 ot have to + # skip it and hope this transition gets assigned later + if isdsts[comp_idx]: + continue + + dstoff = utcoff - utcoffsets[comp_idx] + + if dstoff: + dst_found += 1 + dstoffs[idx] = dstoff + else: + # If we didn't find a valid value for a given index, 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 idx in range(typecnt): + if not dstoffs[idx] and isdsts[idx]: + dstoffs[idx] = 3600 + + return dstoffs + + @staticmethod + def _ts_to_local(trans_idx, trans_list_utc, utcoffsets): + """Generate number of seconds since 1970 *in the local time*. + + This is necessary to easily find the transition times in local time""" + if not trans_list_utc: + return [[], []] + + # Start with the timestamps and modify in-place + trans_list_wall = [list(trans_list_utc), list(trans_list_utc)] + + if len(utcoffsets) > 1: + offset_0 = utcoffsets[0] + offset_1 = utcoffsets[trans_idx[0]] + if offset_1 > offset_0: + offset_1, offset_0 = offset_0, offset_1 + else: + offset_0 = offset_1 = utcoffsets[0] + + trans_list_wall[0][0] += offset_0 + trans_list_wall[1][0] += offset_1 + + for i in range(1, len(trans_idx)): + offset_0 = utcoffsets[trans_idx[i - 1]] + offset_1 = utcoffsets[trans_idx[i]] + + if offset_1 > offset_0: + offset_1, offset_0 = offset_0, offset_1 + + trans_list_wall[0][i] += offset_0 + trans_list_wall[1][i] += offset_1 + + return trans_list_wall + + +class _ttinfo: + __slots__ = ["utcoff", "dstoff", "tzname"] + + def __init__(self, utcoff, dstoff, tzname): + self.utcoff = utcoff + self.dstoff = dstoff + self.tzname = tzname + + def __eq__(self, other): + return ( + self.utcoff == other.utcoff + and self.dstoff == other.dstoff + and self.tzname == other.tzname + ) + + def __repr__(self): # pragma: nocover + return ( + f"{self.__class__.__name__}" + + f"({self.utcoff}, {self.dstoff}, {self.tzname})" + ) + + +_NO_TTINFO = _ttinfo(None, None, None) + + +class _TZStr: + __slots__ = ( + "std", + "dst", + "start", + "end", + "get_trans_info", + "get_trans_info_fromutc", + "dst_diff", + ) + + def __init__( + self, std_abbr, std_offset, dst_abbr, dst_offset, start=None, end=None + ): + self.dst_diff = dst_offset - std_offset + std_offset = _load_timedelta(std_offset) + self.std = _ttinfo( + utcoff=std_offset, dstoff=_load_timedelta(0), tzname=std_abbr + ) + + self.start = start + self.end = end + + dst_offset = _load_timedelta(dst_offset) + delta = _load_timedelta(self.dst_diff) + self.dst = _ttinfo(utcoff=dst_offset, dstoff=delta, tzname=dst_abbr) + + # These are assertions because the constructor should only be called + # by functions that would fail before passing start or end + assert start is not None, "No transition start specified" + assert end is not None, "No transition end specified" + + self.get_trans_info = self._get_trans_info + self.get_trans_info_fromutc = self._get_trans_info_fromutc + + def transitions(self, year): + start = self.start.year_to_epoch(year) + end = self.end.year_to_epoch(year) + return start, end + + def _get_trans_info(self, ts, year, fold): + """Get the information about the current transition - tti""" + start, end = self.transitions(year) + + # 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 == (self.dst_diff >= 0): + end -= self.dst_diff + else: + start += self.dst_diff + + if start < end: + isdst = start <= ts < end + else: + isdst = not (end <= ts < start) + + return self.dst if isdst else self.std + + def _get_trans_info_fromutc(self, ts, year): + start, end = self.transitions(year) + start -= self.std.utcoff.total_seconds() + end -= self.dst.utcoff.total_seconds() + + if start < end: + isdst = start <= ts < end + else: + isdst = not (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. + if self.dst_diff > 0: + ambig_start = end + ambig_end = end + self.dst_diff + else: + ambig_start = start + ambig_end = start - self.dst_diff + + fold = ambig_start <= ts < ambig_end + + return (self.dst if isdst else self.std, fold) + + +def _post_epoch_days_before_year(year): + """Get the number of days between 1970-01-01 and YEAR-01-01""" + y = year - 1 + return y * 365 + y // 4 - y // 100 + y // 400 - EPOCHORDINAL + + +class _DayOffset: + __slots__ = ["d", "julian", "hour", "minute", "second"] + + def __init__(self, d, julian, hour=2, minute=0, second=0): + if not (0 + julian) <= d <= 365: + min_day = 0 + julian + raise ValueError(f"d must be in [{min_day}, 365], not: {d}") + + self.d = d + self.julian = julian + self.hour = hour + self.minute = minute + self.second = second + + def year_to_epoch(self, year): + days_before_year = _post_epoch_days_before_year(year) + + d = self.d + if self.julian and d >= 59 and calendar.isleap(year): + d += 1 + + epoch = (days_before_year + d) * 86400 + epoch += self.hour * 3600 + self.minute * 60 + self.second + + return epoch + + +class _CalendarOffset: + __slots__ = ["m", "w", "d", "hour", "minute", "second"] + + _DAYS_BEFORE_MONTH = ( + -1, + 0, + 31, + 59, + 90, + 120, + 151, + 181, + 212, + 243, + 273, + 304, + 334, + ) + + def __init__(self, m, w, d, hour=2, minute=0, second=0): + if not 0 < m <= 12: + raise ValueError("m must be in (0, 12]") + + if not 0 < w <= 5: + raise ValueError("w must be in (0, 5]") + + if not 0 <= d <= 6: + raise ValueError("d must be in [0, 6]") + + self.m = m + self.w = w + self.d = d + self.hour = hour + self.minute = minute + self.second = second + + @classmethod + def _ymd2ord(cls, year, month, day): + return ( + _post_epoch_days_before_year(year) + + cls._DAYS_BEFORE_MONTH[month] + + (month > 2 and calendar.isleap(year)) + + day + ) + + # TODO: These are not actually epoch dates as they are expressed in local time + def year_to_epoch(self, year): + """Calculates the datetime of the occurrence from the year""" + # We know year and month, we need to convert w, d into day of month + # + # Week 1 is the first week in which day `d` (where 0 = Sunday) appears. + # Week 5 represents the last occurrence of day `d`, so we need to know + # the range of the month. + first_day, days_in_month = calendar.monthrange(year, self.m) + + # 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: -1 % 7 = 6, so we don't need + # to do anything to adjust negative numbers. + # 3. Add 1 because month days are a 1-based index. + month_day = (self.d - (first_day + 1)) % 7 + 1 + + # Now use a 0-based index version of `w` to calculate the w-th + # occurrence of `d` + month_day += (self.w - 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 + + ordinal = self._ymd2ord(year, self.m, month_day) + epoch = ordinal * 86400 + epoch += self.hour * 3600 + self.minute * 60 + self.second + return epoch + + +def _parse_tz_str(tz_str): + # The tz string has the format: + # + # 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]]`` + + offset_str, *start_end_str = tz_str.split(",", 1) + + # fmt: off + parser_re = re.compile( + r"(?P[^<0-9:.+-]+|<[a-zA-Z0-9+\-]+>)" + + r"((?P[+-]?\d{1,2}(:\d{2}(:\d{2})?)?)" + + r"((?P[^0-9:.+-]+|<[a-zA-Z0-9+\-]+>)" + + r"((?P[+-]?\d{1,2}(:\d{2}(:\d{2})?)?))?" + + r")?" + # dst + r")?$" # stdoff + ) + # fmt: on + + m = parser_re.match(offset_str) + + if m is None: + raise ValueError(f"{tz_str} is not a valid TZ string") + + std_abbr = m.group("std") + dst_abbr = m.group("dst") + dst_offset = None + + std_abbr = std_abbr.strip("<>") + + if dst_abbr: + dst_abbr = dst_abbr.strip("<>") + + if std_offset := m.group("stdoff"): + try: + std_offset = _parse_tz_delta(std_offset) + except ValueError as e: + raise ValueError(f"Invalid STD offset in {tz_str}") from e + else: + std_offset = 0 + + if dst_abbr is not None: + if dst_offset := m.group("dstoff"): + try: + dst_offset = _parse_tz_delta(dst_offset) + except ValueError as e: + raise ValueError(f"Invalid DST offset in {tz_str}") from e + else: + dst_offset = std_offset + 3600 + + if not start_end_str: + raise ValueError(f"Missing transition rules: {tz_str}") + + start_end_strs = start_end_str[0].split(",", 1) + try: + start, end = (_parse_dst_start_end(x) for x in start_end_strs) + except ValueError as e: + raise ValueError(f"Invalid TZ string: {tz_str}") from e + + return _TZStr(std_abbr, std_offset, dst_abbr, dst_offset, start, end) + elif start_end_str: + raise ValueError(f"Transition rule present without DST: {tz_str}") + else: + # This is a static ttinfo, don't return _TZStr + return _ttinfo( + _load_timedelta(std_offset), _load_timedelta(0), std_abbr + ) + + +def _parse_dst_start_end(dststr): + date, *time = dststr.split("/") + if date[0] == "M": + n_is_julian = False + m = re.match(r"M(\d{1,2})\.(\d).(\d)$", date) + if m is None: + raise ValueError(f"Invalid dst start/end date: {dststr}") + date_offset = tuple(map(int, m.groups())) + offset = _CalendarOffset(*date_offset) + else: + if date[0] == "J": + n_is_julian = True + date = date[1:] + else: + n_is_julian = False + + doy = int(date) + offset = _DayOffset(doy, n_is_julian) + + if time: + time_components = list(map(int, time[0].split(":"))) + n_components = len(time_components) + if n_components < 3: + time_components.extend([0] * (3 - n_components)) + offset.hour, offset.minute, offset.second = time_components + + return offset + + +def _parse_tz_delta(tz_delta): + match = re.match( + r"(?P[+-])?(?P\d{1,2})(:(?P\d{2})(:(?P\d{2}))?)?", + tz_delta, + ) + # Anything passed to this function should already have hit an equivalent + # regular expression to find the section to parse. + assert match is not None, tz_delta + + h, m, s = ( + int(v) if v is not None else 0 + for v in map(match.group, ("h", "m", "s")) + ) + + total = h * 3600 + m * 60 + s + + if not -86400 < total < 86400: + raise ValueError( + "Offset must be strictly between -24h and +24h:" + tz_delta + ) + + # Yes, +5 maps to an offset of -5h + if match.group("sign") != "-": + total *= -1 + + return total diff --git a/Makefile.pre.in b/Makefile.pre.in index d545a9efb3c..dbfd805f1a0 100644 --- a/Makefile.pre.in +++ b/Makefile.pre.in @@ -197,6 +197,9 @@ OPENSSL_INCLUDES=@OPENSSL_INCLUDES@ OPENSSL_LIBS=@OPENSSL_LIBS@ OPENSSL_LDFLAGS=@OPENSSL_LDFLAGS@ +# Default zoneinfo.TZPATH. Added here to expose it in sysconfig.get_config_var +TZPATH=@TZPATH@ + # Modes for directories, executables and data files created by the # install process. Default to user-only-writable for all file types. DIRMODE= 755 diff --git a/Modules/Setup b/Modules/Setup index 87e73bac78f..02cfb67518d 100644 --- a/Modules/Setup +++ b/Modules/Setup @@ -181,6 +181,7 @@ _symtable symtablemodule.c #_elementtree -I$(srcdir)/Modules/expat -DHAVE_EXPAT_CONFIG_H -DUSE_PYEXPAT_CAPI _elementtree.c # elementtree accelerator #_pickle _pickle.c # pickle accelerator #_datetime _datetimemodule.c # datetime accelerator +#_zoneinfo _zoneinfo.c # zoneinfo accelerator #_bisect _bisectmodule.c # Bisection algorithms #_heapq _heapqmodule.c # Heap queue algorithm #_asyncio _asynciomodule.c # Fast asyncio Future diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c new file mode 100644 index 00000000000..9f5e64d8486 --- /dev/null +++ b/Modules/_zoneinfo.c @@ -0,0 +1,2695 @@ +#include "Python.h" +#include "structmember.h" + +#include +#include +#include + +#include "datetime.h" + +// Imports +static PyObject *io_open = NULL; +static PyObject *_tzpath_find_tzfile = NULL; +static PyObject *_common_mod = NULL; + +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; + unsigned int num_transitions; + unsigned int 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; + uint8_t week; + uint8_t day; + int8_t hour; + int8_t minute; + int8_t second; +} CalendarRule; + +typedef struct { + TransitionRuleType base; + uint8_t julian; + unsigned int day; + int8_t hour; + int8_t minute; + int8_t second; +} DayRule; + +struct StrongCacheNode { + StrongCacheNode *next; + StrongCacheNode *prev; + PyObject *key; + PyObject *zone; +}; + +static PyTypeObject PyZoneInfo_ZoneInfoType; + +// Globals +static PyObject *TIMEDELTA_CACHE = NULL; +static PyObject *ZONEINFO_WEAK_CACHE = NULL; +static StrongCacheNode *ZONEINFO_STRONG_CACHE = NULL; +static size_t ZONEINFO_STRONG_CACHE_MAX_SIZE = 8; + +static _ttinfo NO_TTINFO = {NULL, NULL, NULL, 0}; + +// 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; + +// Forward declarations +static int +load_data(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(PyObject *tz_str_obj, _tzrule *out); + +static ssize_t +parse_abbr(const char *const p, PyObject **abbr); +static ssize_t +parse_tz_delta(const char *const p, long *total_seconds); +static ssize_t +parse_transition_time(const char *const p, int8_t *hour, int8_t *minute, + int8_t *second); +static ssize_t +parse_transition_rule(const char *const 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(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(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(long seconds); + +static int +get_local_timestamp(PyObject *dt, int64_t *local_ts); +static _ttinfo * +find_ttinfo(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 void +eject_from_strong_cache(const PyTypeObject *const type, PyObject *key); +static void +clear_strong_cache(const PyTypeObject *const type); +static void +update_strong_cache(const PyTypeObject *const type, PyObject *key, + PyObject *zone); +static PyObject * +zone_from_strong_cache(const PyTypeObject *const type, PyObject *key); + +static PyObject * +zoneinfo_new_instance(PyTypeObject *type, PyObject *key) +{ + PyObject *file_obj = NULL; + PyObject *file_path = NULL; + + file_path = PyObject_CallFunctionObjArgs(_tzpath_find_tzfile, key, NULL); + if (file_path == NULL) { + return NULL; + } + else if (file_path == Py_None) { + file_obj = PyObject_CallMethod(_common_mod, "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) { + file_obj = PyObject_CallFunction(io_open, "Os", file_path, "rb"); + if (file_obj == NULL) { + goto error; + } + } + + if (load_data((PyZoneInfo_ZoneInfo *)self, file_obj)) { + goto error; + } + + PyObject *rv = PyObject_CallMethod(file_obj, "close", NULL); + Py_DECREF(file_obj); + file_obj = NULL; + if (rv == NULL) { + goto error; + } + Py_DECREF(rv); + + ((PyZoneInfo_ZoneInfo *)self)->key = key; + Py_INCREF(key); + + goto cleanup; +error: + Py_XDECREF(self); + self = NULL; +cleanup: + if (file_obj != NULL) { + PyObject *tmp = PyObject_CallMethod(file_obj, "close", NULL); + Py_DECREF(tmp); + Py_DECREF(file_obj); + } + Py_DECREF(file_path); + return self; +} + +static PyObject * +get_weak_cache(PyTypeObject *type) +{ + if (type == &PyZoneInfo_ZoneInfoType) { + return 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; + } +} + +static PyObject * +zoneinfo_new(PyTypeObject *type, PyObject *args, PyObject *kw) +{ + PyObject *key = NULL; + static char *kwlist[] = {"key", NULL}; + if (PyArg_ParseTupleAndKeywords(args, kw, "O", kwlist, &key) == 0) { + return NULL; + } + + PyObject *instance = zone_from_strong_cache(type, key); + if (instance != NULL) { + return instance; + } + + PyObject *weak_cache = get_weak_cache(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(type, key); + if (tmp == NULL) { + return NULL; + } + + instance = + PyObject_CallMethod(weak_cache, "setdefault", "OO", key, tmp); + ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE; + + Py_DECREF(tmp); + + if (instance == NULL) { + return NULL; + } + } + + update_strong_cache(type, key, instance); + return instance; +} + +static void +zoneinfo_dealloc(PyObject *obj_self) +{ + PyZoneInfo_ZoneInfo *self = (PyZoneInfo_ZoneInfo *)obj_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)); + + Py_XDECREF(self->key); + Py_XDECREF(self->file_repr); + + Py_TYPE(self)->tp_free((PyObject *)self); +} + +static PyObject * +zoneinfo_from_file(PyTypeObject *type, PyObject *args, PyObject *kwargs) +{ + PyObject *file_obj = NULL; + PyObject *file_repr = NULL; + PyObject *key = Py_None; + PyZoneInfo_ZoneInfo *self = NULL; + + static char *kwlist[] = {"", "key", NULL}; + if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|O", kwlist, &file_obj, + &key)) { + return NULL; + } + + PyObject *obj_self = (PyObject *)(type->tp_alloc(type, 0)); + self = (PyZoneInfo_ZoneInfo *)obj_self; + if (self == NULL) { + return NULL; + } + + file_repr = PyUnicode_FromFormat("%R", file_obj); + if (file_repr == NULL) { + goto error; + } + + if (load_data(self, file_obj)) { + goto error; + } + + self->source = SOURCE_FILE; + self->file_repr = file_repr; + self->key = key; + Py_INCREF(key); + + return obj_self; +error: + Py_XDECREF(file_repr); + Py_XDECREF(self); + return NULL; +} + +static PyObject * +zoneinfo_no_cache(PyTypeObject *cls, PyObject *args, PyObject *kwargs) +{ + static char *kwlist[] = {"key", NULL}; + PyObject *key = NULL; + if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O", kwlist, &key)) { + return NULL; + } + + PyObject *out = zoneinfo_new_instance(cls, key); + if (out != NULL) { + ((PyZoneInfo_ZoneInfo *)out)->source = SOURCE_NOCACHE; + } + + return out; +} + +static PyObject * +zoneinfo_clear_cache(PyObject *cls, PyObject *args, PyObject *kwargs) +{ + PyObject *only_keys = NULL; + static char *kwlist[] = {"only_keys", NULL}; + + if (!(PyArg_ParseTupleAndKeywords(args, kwargs, "|$O", kwlist, + &only_keys))) { + return NULL; + } + + PyTypeObject *type = (PyTypeObject *)cls; + PyObject *weak_cache = get_weak_cache(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(type); + ZONEINFO_STRONG_CACHE = NULL; + } + 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 + eject_from_strong_cache(type, item); + + // 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; +} + +static PyObject * +zoneinfo_utcoffset(PyObject *self, PyObject *dt) +{ + _ttinfo *tti = find_ttinfo((PyZoneInfo_ZoneInfo *)self, dt); + if (tti == NULL) { + return NULL; + } + Py_INCREF(tti->utcoff); + return tti->utcoff; +} + +static PyObject * +zoneinfo_dst(PyObject *self, PyObject *dt) +{ + _ttinfo *tti = find_ttinfo((PyZoneInfo_ZoneInfo *)self, dt); + if (tti == NULL) { + return NULL; + } + Py_INCREF(tti->dstoff); + return tti->dstoff; +} + +static PyObject * +zoneinfo_tzname(PyObject *self, PyObject *dt) +{ + _ttinfo *tti = find_ttinfo((PyZoneInfo_ZoneInfo *)self, dt); + if (tti == NULL) { + return NULL; + } + Py_INCREF(tti->tzname); + return tti->tzname; +} + +#define HASTZINFO(p) (((_PyDateTime_BaseTZInfo *)(p))->hastzinfo) +#define GET_DT_TZINFO(p) \ + (HASTZINFO(p) ? ((PyDateTime_DateTime *)(p))->tzinfo : Py_None) + +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, ×tamp)) { + 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"); + PyObject *args = PyTuple_New(0); + PyObject *kwargs = PyDict_New(); + + Py_DECREF(tmp); + if (args == NULL || kwargs == NULL || replace == NULL) { + Py_XDECREF(args); + Py_XDECREF(kwargs); + Py_XDECREF(replace); + return NULL; + } + + dt = NULL; + if (!PyDict_SetItemString(kwargs, "fold", _PyLong_One)) { + 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)) { + Py_INCREF(self->key); + return 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 = PyImport_ImportModule("pickle"); + if (pickle == NULL) { + return NULL; + } + + PyObject *pickle_error = + PyObject_GetAttrString(pickle, "PicklingError"); + Py_DECREF(pickle); + 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; +} + +static PyObject * +zoneinfo__unpickle(PyTypeObject *cls, PyObject *args) +{ + PyObject *key; + unsigned char from_cache; + if (!PyArg_ParseTuple(args, "OB", &key, &from_cache)) { + return NULL; + } + + if (from_cache) { + PyObject *val_args = Py_BuildValue("(O)", key); + if (val_args == NULL) { + return NULL; + } + + PyObject *rv = zoneinfo_new(cls, val_args, NULL); + + Py_DECREF(val_args); + return rv; + } + else { + return zoneinfo_new_instance(cls, 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(long seconds) +{ + PyObject *rv = NULL; + PyObject *pyoffset = PyLong_FromLong(seconds); + if (pyoffset == NULL) { + return NULL; + } + int contains = PyDict_Contains(TIMEDELTA_CACHE, pyoffset); + if (contains == -1) { + goto error; + } + + if (!contains) { + PyObject *tmp = PyDateTimeAPI->Delta_FromDelta( + 0, seconds, 0, 1, PyDateTimeAPI->DeltaType); + + if (tmp == NULL) { + goto error; + } + + rv = PyDict_SetDefault(TIMEDELTA_CACHE, pyoffset, tmp); + Py_DECREF(tmp); + } + else { + rv = PyDict_GetItem(TIMEDELTA_CACHE, pyoffset); + } + + Py_DECREF(pyoffset); + Py_INCREF(rv); + return rv; +error: + Py_DECREF(pyoffset); + return NULL; +} + +/* 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(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(utcoffset); + if (out->utcoff == NULL) { + return -1; + } + + out->dstoff = load_timedelta(dstoffset); + if (out->dstoff == NULL) { + return -1; + } + + out->tzname = tzname; + Py_INCREF(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(PyZoneInfo_ZoneInfo *self, PyObject *file_obj) +{ + 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(_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 == -1) { + goto error; + } + + Py_ssize_t num_ttinfos = PyTuple_Size(utcoff_list); + if (num_ttinfos == -1) { + 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)); + trans_idx = PyMem_Malloc(self->num_transitions * sizeof(Py_ssize_t)); + + for (Py_ssize_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 (Py_ssize_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)); + for (size_t i = 0; i < self->num_ttinfos; ++i) { + PyObject *tzname = PyTuple_GetItem(abbr, i); + if (tzname == NULL) { + goto error; + } + + ttinfos_allocated++; + if (build_ttinfo(utcoff[i], dstoff[i], tzname, &(self->_ttinfos[i]))) { + goto error; + } + } + + // Build our mapping from transition to the ttinfo that applies + self->trans_ttinfos = + PyMem_Calloc(self->num_transitions, sizeof(_ttinfo *)); + 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(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(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_DECREF(tti_after->dstoff); + tti_after->dstoff = tti->dstoff; + Py_INCREF(tti_after->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; + } + } + + int rv = 0; + 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) + (int64_t)(self->second)); +} + +/* Constructor for CalendarRule. */ +int +calendarrule_new(uint8_t month, uint8_t week, uint8_t day, int8_t hour, + int8_t minute, int8_t 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 <= 0 || month > 12) { + PyErr_Format(PyExc_ValueError, "Month must be in (0, 12]"); + return -1; + } + + if (week <= 0 || week > 5) { + PyErr_Format(PyExc_ValueError, "Week must be in (0, 5]"); + return -1; + } + + // day is an unsigned integer, so day < 0 should always return false, but + // if day's type changes to a signed integer *without* changing this value, + // it may create a bug. Considering that the compiler should be able to + // optimize out the first comparison if day is an unsigned integer anyway, + // we will leave this comparison in place and disable the compiler warning. +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wtype-limits" + if (day < 0 || day > 6) { +#pragma GCC diagnostic pop + PyErr_Format(PyExc_ValueError, "Day must be in [0, 6]"); + return -1; + } + + TransitionRuleType base = {&calendarrule_year_to_timestamp}; + + CalendarRule new_offset = { + .base = base, + .month = month, + .week = week, + .day = day, + .hour = hour, + .minute = minute, + .second = 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. + unsigned int day = self->day; + if (self->julian && day >= 59 && is_leap_year(year)) { + day += 1; + } + + return ((days_before_year + day) * 86400) + (self->hour * 3600) + + (self->minute * 60) + self->second; +} + +/* Constructor for DayRule. */ +static int +dayrule_new(uint8_t julian, unsigned int day, int8_t hour, int8_t minute, + int8_t 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 [%u, 365], not: %u", + julian, day); + return -1; + } + + TransitionRuleType base = { + &dayrule_year_to_timestamp, + }; + + DayRule tmp = { + .base = base, + .julian = julian, + .day = day, + .hour = hour, + .minute = minute, + .second = 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 + * unncessary 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(PyObject *tz_str_obj, _tzrule *out) +{ + PyObject *std_abbr = NULL; + PyObject *dst_abbr = NULL; + TransitionRuleType *start = NULL; + TransitionRuleType *end = NULL; + long std_offset, dst_offset; + + char *tz_str = PyBytes_AsString(tz_str_obj); + if (tz_str == NULL) { + return -1; + } + char *p = tz_str; + + // Read the `std` abbreviation, which must be at least 3 characters long. + ssize_t num_chars = parse_abbr(p, &std_abbr); + if (num_chars < 1) { + PyErr_Format(PyExc_ValueError, "Invalid STD format in %R", tz_str_obj); + goto error; + } + + p += num_chars; + + // Now read the STD offset, which is required + num_chars = parse_tz_delta(p, &std_offset); + if (num_chars < 0) { + PyErr_Format(PyExc_ValueError, "Invalid STD offset in %R", tz_str_obj); + goto error; + } + p += num_chars; + + // 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; + } + + num_chars = parse_abbr(p, &dst_abbr); + if (num_chars < 1) { + PyErr_Format(PyExc_ValueError, "Invalid DST format in %R", tz_str_obj); + goto error; + } + p += num_chars; + + 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 { + num_chars = parse_tz_delta(p, &dst_offset); + if (num_chars < 0) { + PyErr_Format(PyExc_ValueError, "Invalid DST offset in %R", + tz_str_obj); + goto error; + } + + p += num_chars; + } + + 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++; + + num_chars = parse_transition_rule(p, transitions[i]); + if (num_chars < 0) { + PyErr_Format(PyExc_ValueError, + "Malformed transition rule in TZ string: %R", + tz_str_obj); + goto error; + } + p += num_chars; + } + + if (*p != '\0') { + PyErr_Format(PyExc_ValueError, + "Extraneous characters at end of TZ string: %R", + tz_str_obj); + goto error; + } + +complete: + build_tzrule(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 ssize_t +parse_uint(const char *const p) +{ + if (!isdigit(*p)) { + return -1; + } + + return (*p) - '0'; +} + +/* Parse the STD and DST abbreviations from a TZ string. */ +static ssize_t +parse_abbr(const char *const p, PyObject **abbr) +{ + const char *ptr = p; + char buff = *ptr; + const char *str_start; + const char *str_end; + + if (*ptr == '<') { + 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 (!isalpha(buff) && !isdigit(buff) && buff != '+' && + buff != '-') { + return -1; + } + ptr++; + } + str_end = ptr; + ptr++; + } + else { + str_start = p; + // 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 (isalpha(*ptr)) { + ptr++; + } + str_end = ptr; + } + + *abbr = PyUnicode_FromStringAndSize(str_start, str_end - str_start); + if (abbr == NULL) { + return -1; + } + + return ptr - p; +} + +/* Parse a UTC offset from a TZ str. */ +static ssize_t +parse_tz_delta(const char *const 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. + long sign = -1; + long hours = 0; + long minutes = 0; + long seconds = 0; + + const char *ptr = p; + char buff = *ptr; + if (buff == '-' || buff == '+') { + // 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 '+' ). + if (buff == '-') { + sign = 1; + } + + ptr++; + } + + // The hour can be 1 or 2 numeric characters + for (size_t i = 0; i < 2; ++i) { + buff = *ptr; + if (!isdigit(buff)) { + if (i == 0) { + return -1; + } + else { + break; + } + } + + hours *= 10; + hours += buff - '0'; + ptr++; + } + + if (hours > 24 || hours < 0) { + return -1; + } + + // Minutes and seconds always of the format ":dd" + long *outputs[2] = {&minutes, &seconds}; + for (size_t i = 0; i < 2; ++i) { + if (*ptr != ':') { + goto complete; + } + ptr++; + + for (size_t j = 0; j < 2; ++j) { + buff = *ptr; + if (!isdigit(buff)) { + return -1; + } + *(outputs[i]) *= 10; + *(outputs[i]) += buff - '0'; + ptr++; + } + } + +complete: + *total_seconds = sign * ((hours * 3600) + (minutes * 60) + seconds); + + return ptr - p; +} + +/* Parse the date portion of a transition rule. */ +static ssize_t +parse_transition_rule(const char *const 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; + int8_t hour = 2; + int8_t minute = 0; + int8_t 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') { + uint8_t month, week, day; + ptr++; + ssize_t tmp = parse_uint(ptr); + if (tmp < 0) { + return -1; + } + month = (uint8_t)tmp; + ptr++; + if (*ptr != '.') { + tmp = parse_uint(ptr); + if (tmp < 0) { + return -1; + } + + month *= 10; + month += (uint8_t)tmp; + ptr++; + } + + uint8_t *values[2] = {&week, &day}; + for (size_t i = 0; i < 2; ++i) { + if (*ptr != '.') { + return -1; + } + ptr++; + + tmp = parse_uint(ptr); + if (tmp < 0) { + return -1; + } + ptr++; + + *(values[i]) = tmp; + } + + if (*ptr == '/') { + ptr++; + ssize_t num_chars = + parse_transition_time(ptr, &hour, &minute, &second); + if (num_chars < 0) { + return -1; + } + ptr += num_chars; + } + + 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 { + uint8_t julian = 0; + unsigned int day = 0; + if (*ptr == 'J') { + julian = 1; + ptr++; + } + + for (size_t i = 0; i < 3; ++i) { + if (!isdigit(*ptr)) { + if (i == 0) { + return -1; + } + break; + } + day *= 10; + day += (*ptr) - '0'; + ptr++; + } + + if (*ptr == '/') { + ptr++; + ssize_t num_chars = + parse_transition_time(ptr, &hour, &minute, &second); + if (num_chars < 0) { + return -1; + } + ptr += num_chars; + } + + 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; + } + + return ptr - p; +} + +/* Parse the time portion of a transition rule (e.g. following an /) */ +static ssize_t +parse_transition_time(const char *const p, int8_t *hour, int8_t *minute, + int8_t *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, but the current version only supports [0, 99]. + // + // TODO: Support the full range of transition hours. + int8_t *components[3] = {hour, minute, second}; + const char *ptr = p; + int8_t sign = 1; + + if (*ptr == '-' || *ptr == '+') { + if (*ptr == '-') { + sign = -1; + } + ptr++; + } + + for (size_t i = 0; i < 3; ++i) { + if (i > 0) { + if (*ptr != ':') { + break; + } + ptr++; + } + + uint8_t buff = 0; + for (size_t j = 0; j < 2; j++) { + if (!isdigit(*ptr)) { + if (i == 0 && j > 0) { + break; + } + return -1; + } + + buff *= 10; + buff += (*ptr) - '0'; + ptr++; + } + + *(components[i]) = sign * buff; + } + + return ptr - p; +} + +/* 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(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(std_offset, 0, std_abbr, &rv.std)) { + goto error; + } + + if (dst_abbr != NULL) { + rv.dst_diff = dst_offset - std_offset; + if (build_ttinfo(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(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 &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) * 86400 + + (int64_t)(hour * 3600 + minute * 60 + second); + + return 0; +} + +///// +// Functions for cache handling + +/* Constructor for StrongCacheNode */ +static StrongCacheNode * +strong_cache_node_new(PyObject *key, PyObject *zone) +{ + StrongCacheNode *node = PyMem_Malloc(sizeof(StrongCacheNode)); + if (node == NULL) { + return NULL; + } + + Py_INCREF(key); + Py_INCREF(zone); + + node->next = NULL; + node->prev = NULL; + node->key = key; + node->zone = 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(StrongCacheNode *node) +{ + if (ZONEINFO_STRONG_CACHE == node) { + 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) { + if (PyObject_RichCompareBool(key, node->key, Py_EQ)) { + 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 void +eject_from_strong_cache(const PyTypeObject *const type, PyObject *key) +{ + if (type != &PyZoneInfo_ZoneInfoType) { + return; + } + + StrongCacheNode *node = find_in_strong_cache(ZONEINFO_STRONG_CACHE, key); + if (node != NULL) { + remove_from_strong_cache(node); + + strong_cache_node_free(node); + } +} + +/* 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(StrongCacheNode **root, StrongCacheNode *node) +{ + StrongCacheNode *root_p = *root; + if (root_p == node) { + return; + } + + remove_from_strong_cache(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(const PyTypeObject *const type, PyObject *const key) +{ + if (type != &PyZoneInfo_ZoneInfoType) { + return NULL; // Strong cache currently only implemented for base class + } + + StrongCacheNode *node = find_in_strong_cache(ZONEINFO_STRONG_CACHE, key); + + if (node != NULL) { + move_strong_cache_node_to_front(&ZONEINFO_STRONG_CACHE, node); + Py_INCREF(node->zone); + return 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(const PyTypeObject *const type, PyObject *key, + PyObject *zone) +{ + if (type != &PyZoneInfo_ZoneInfoType) { + return; + } + + StrongCacheNode *new_node = strong_cache_node_new(key, zone); + + move_strong_cache_node_to_front(&ZONEINFO_STRONG_CACHE, 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(const PyTypeObject *const type) +{ + if (type != &PyZoneInfo_ZoneInfoType) { + return; + } + + strong_cache_free(ZONEINFO_STRONG_CACHE); +} + +static PyObject * +new_weak_cache() +{ + PyObject *weakref_module = PyImport_ImportModule("weakref"); + if (weakref_module == NULL) { + return NULL; + } + + PyObject *weak_cache = + PyObject_CallMethod(weakref_module, "WeakValueDictionary", ""); + Py_DECREF(weakref_module); + return weak_cache; +} + +static int +initialize_caches() +{ + if (TIMEDELTA_CACHE == NULL) { + TIMEDELTA_CACHE = PyDict_New(); + } + else { + Py_INCREF(TIMEDELTA_CACHE); + } + + if (TIMEDELTA_CACHE == NULL) { + return -1; + } + + if (ZONEINFO_WEAK_CACHE == NULL) { + ZONEINFO_WEAK_CACHE = new_weak_cache(); + } + else { + Py_INCREF(ZONEINFO_WEAK_CACHE); + } + + if (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; + } + + PyObject_SetAttrString((PyObject *)cls, "_weak_cache", weak_cache); + Py_RETURN_NONE; +} + +///// +// Specify the ZoneInfo type +static PyMethodDef zoneinfo_methods[] = { + {"clear_cache", (PyCFunction)(void (*)(void))zoneinfo_clear_cache, + METH_VARARGS | METH_KEYWORDS | METH_CLASS, + PyDoc_STR("Clear the ZoneInfo cache.")}, + {"no_cache", (PyCFunction)(void (*)(void))zoneinfo_no_cache, + METH_VARARGS | METH_KEYWORDS | METH_CLASS, + PyDoc_STR("Get a new instance of ZoneInfo, bypassing the cache.")}, + {"from_file", (PyCFunction)(void (*)(void))zoneinfo_from_file, + METH_VARARGS | METH_KEYWORDS | METH_CLASS, + PyDoc_STR("Create a ZoneInfo file from a file object.")}, + {"utcoffset", (PyCFunction)zoneinfo_utcoffset, METH_O, + PyDoc_STR("Retrieve a timedelta representing the UTC offset in a zone at " + "the given datetime.")}, + {"dst", (PyCFunction)zoneinfo_dst, METH_O, + PyDoc_STR("Retrieve a timedelta representing the amount of DST applied " + "in a zone at the given datetime.")}, + {"tzname", (PyCFunction)zoneinfo_tzname, METH_O, + PyDoc_STR("Retrieve a string containing the abbreviation for the time " + "zone that applies in a zone at a given datetime.")}, + {"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.")}, + {"_unpickle", (PyCFunction)zoneinfo__unpickle, METH_VARARGS | METH_CLASS, + PyDoc_STR("Private method used in unpickling.")}, + {"__init_subclass__", (PyCFunction)(void (*)(void))zoneinfo_init_subclass, + METH_VARARGS | METH_KEYWORDS, + PyDoc_STR("Function to initialize subclasses.")}, + {NULL} /* Sentinel */ +}; + +static PyMemberDef zoneinfo_members[] = { + {.name = "key", + .offset = offsetof(PyZoneInfo_ZoneInfo, key), + .type = T_OBJECT_EX, + .flags = READONLY, + .doc = NULL}, + {NULL}, /* Sentinel */ +}; + +static PyTypeObject PyZoneInfo_ZoneInfoType = { + PyVarObject_HEAD_INIT(NULL, 0) // + .tp_name = "zoneinfo.ZoneInfo", + .tp_basicsize = sizeof(PyZoneInfo_ZoneInfo), + .tp_weaklistoffset = offsetof(PyZoneInfo_ZoneInfo, weakreflist), + .tp_repr = (reprfunc)zoneinfo_repr, + .tp_str = (reprfunc)zoneinfo_str, + .tp_getattro = PyObject_GenericGetAttr, + .tp_flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE), + /* .tp_doc = zoneinfo_doc, */ + .tp_methods = zoneinfo_methods, + .tp_members = zoneinfo_members, + .tp_new = zoneinfo_new, + .tp_dealloc = zoneinfo_dealloc, +}; + +///// +// Specify the _zoneinfo module +static PyMethodDef module_methods[] = {{NULL, NULL}}; +static void +module_free() +{ + Py_XDECREF(_tzpath_find_tzfile); + _tzpath_find_tzfile = NULL; + + Py_XDECREF(_common_mod); + _common_mod = NULL; + + Py_XDECREF(io_open); + io_open = NULL; + + xdecref_ttinfo(&NO_TTINFO); + + Py_XDECREF(TIMEDELTA_CACHE); + if (!Py_REFCNT(TIMEDELTA_CACHE)) { + TIMEDELTA_CACHE = NULL; + } + + Py_XDECREF(ZONEINFO_WEAK_CACHE); + if (!Py_REFCNT(ZONEINFO_WEAK_CACHE)) { + ZONEINFO_WEAK_CACHE = NULL; + } + + strong_cache_free(ZONEINFO_STRONG_CACHE); + ZONEINFO_STRONG_CACHE = NULL; +} + +static int +zoneinfomodule_exec(PyObject *m) +{ + PyDateTime_IMPORT; + PyZoneInfo_ZoneInfoType.tp_base = PyDateTimeAPI->TZInfoType; + if (PyType_Ready(&PyZoneInfo_ZoneInfoType) < 0) { + goto error; + } + + Py_INCREF(&PyZoneInfo_ZoneInfoType); + PyModule_AddObject(m, "ZoneInfo", (PyObject *)&PyZoneInfo_ZoneInfoType); + + /* Populate imports */ + PyObject *_tzpath_module = PyImport_ImportModule("zoneinfo._tzpath"); + if (_tzpath_module == NULL) { + goto error; + } + + _tzpath_find_tzfile = + PyObject_GetAttrString(_tzpath_module, "find_tzfile"); + Py_DECREF(_tzpath_module); + if (_tzpath_find_tzfile == NULL) { + goto error; + } + + PyObject *io_module = PyImport_ImportModule("io"); + if (io_module == NULL) { + goto error; + } + + io_open = PyObject_GetAttrString(io_module, "open"); + Py_DECREF(io_module); + if (io_open == NULL) { + goto error; + } + + _common_mod = PyImport_ImportModule("zoneinfo._common"); + if (_common_mod == NULL) { + goto error; + } + + if (NO_TTINFO.utcoff == NULL) { + NO_TTINFO.utcoff = Py_None; + NO_TTINFO.dstoff = Py_None; + NO_TTINFO.tzname = Py_None; + + for (size_t i = 0; i < 3; ++i) { + Py_INCREF(Py_None); + } + } + + if (initialize_caches()) { + goto error; + } + + return 0; + +error: + return -1; +} + +static PyModuleDef_Slot zoneinfomodule_slots[] = { + {Py_mod_exec, zoneinfomodule_exec}, {0, NULL}}; + +static struct PyModuleDef zoneinfomodule = { + PyModuleDef_HEAD_INIT, + .m_name = "_zoneinfo", + .m_doc = "C implementation of the zoneinfo module", + .m_size = 0, + .m_methods = module_methods, + .m_slots = zoneinfomodule_slots, + .m_free = (freefunc)module_free}; + +PyMODINIT_FUNC +PyInit__zoneinfo(void) +{ + return PyModuleDef_Init(&zoneinfomodule); +} diff --git a/configure b/configure index 64bcde6bfdf..56d66d02352 100755 --- a/configure +++ b/configure @@ -658,6 +658,7 @@ LIBFFI_INCLUDEDIR PKG_CONFIG_LIBDIR PKG_CONFIG_PATH PKG_CONFIG +TZPATH SHLIBS CFLAGSFORSHARED LINKFORSHARED @@ -819,6 +820,7 @@ with_assertions enable_optimizations with_lto with_hash_algorithm +with_tzpath with_address_sanitizer with_memory_sanitizer with_undefined_behavior_sanitizer @@ -1525,6 +1527,9 @@ Optional Packages: --with-hash-algorithm=[fnv|siphash24] select hash algorithm for use in Python/pyhash.c (default is SipHash24) + --with-tzpath= + Select the default time zone search path for zoneinfo.TZPATH + --with-address-sanitizer enable AddressSanitizer memory error detector, 'asan' (default is no) @@ -10154,6 +10159,47 @@ $as_echo "default" >&6; } fi +validate_tzpath() { + # Checks that each element of hte path is an absolute path + if test -z "$1"; then + # Empty string is allowed: it indicates no system TZPATH + return 0 + fi + + # Bad paths are those that don't start with / + if ( echo $1 | grep -qE '(^|:)([^/]|$)' ); then + as_fn_error $? "--with-tzpath must contain only absolute paths, not $1" "$LINENO" 5 + return 1; + fi +} + +TZPATH="/usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo" +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-tzpath" >&5 +$as_echo_n "checking for --with-tzpath... " >&6; } + +# Check whether --with-tzpath was given. +if test "${with_tzpath+set}" = set; then : + withval=$with_tzpath; +case "$withval" in + yes) + as_fn_error $? "--with-tzpath requires a value" "$LINENO" 5 + ;; + *) + validate_tzpath "$withval" + TZPATH="$withval" + { $as_echo "$as_me:${as_lineno-$LINENO}: result: \"$withval\"" >&5 +$as_echo "\"$withval\"" >&6; } + ;; +esac + +else + validate_tzpath "$TZPATH" + { $as_echo "$as_me:${as_lineno-$LINENO}: result: \"$TZPATH\"" >&5 +$as_echo "\"$TZPATH\"" >&6; } +fi + + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-address-sanitizer" >&5 $as_echo_n "checking for --with-address-sanitizer... " >&6; } diff --git a/configure.ac b/configure.ac index 21c47b56358..497d7c191d5 100644 --- a/configure.ac +++ b/configure.ac @@ -2946,6 +2946,42 @@ esac ], [AC_MSG_RESULT(default)]) +validate_tzpath() { + # Checks that each element of hte path is an absolute path + if test -z "$1"; then + # Empty string is allowed: it indicates no system TZPATH + return 0 + fi + + # Bad paths are those that don't start with / + dnl quadrigraphs "@<:@" and "@:>@" produce "[" and "]" in the output + if ( echo $1 | grep -qE '(^|:)(@<:@^/@:>@|$)' ); then + AC_MSG_ERROR([--with-tzpath must contain only absolute paths, not $1]) + return 1; + fi +} + +TZPATH="/usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo" +AC_MSG_CHECKING(for --with-tzpath) +AC_ARG_WITH(tzpath, + AS_HELP_STRING([--with-tzpath=] + [Select the default time zone search path for zoneinfo.TZPATH]), +[ +case "$withval" in + yes) + AC_MSG_ERROR([--with-tzpath requires a value]) + ;; + *) + validate_tzpath "$withval" + TZPATH="$withval" + AC_MSG_RESULT("$withval") + ;; +esac +], +[validate_tzpath "$TZPATH" + AC_MSG_RESULT("$TZPATH")]) +AC_SUBST(TZPATH) + AC_MSG_CHECKING(for --with-address-sanitizer) AC_ARG_WITH(address_sanitizer, AS_HELP_STRING([--with-address-sanitizer], diff --git a/setup.py b/setup.py index 794ba2f7662..68fc3120cc3 100644 --- a/setup.py +++ b/setup.py @@ -304,6 +304,17 @@ def find_library_file(compiler, libname, std_dirs, paths): else: assert False, "Internal error: Path not found in std_dirs or paths" +def validate_tzpath(): + base_tzpath = sysconfig.get_config_var('TZPATH') + if not base_tzpath: + return + + tzpaths = base_tzpath.split(os.pathsep) + bad_paths = [tzpath for tzpath in tzpaths if not os.path.isabs(tzpath)] + if bad_paths: + raise ValueError('TZPATH must contain only absolute paths, ' + + f'found:\n{tzpaths!r}\nwith invalid paths:\n' + + f'{bad_paths!r}') def find_module_file(module, dirlist): """Find a module in a set of possible folders. If it is not found @@ -816,6 +827,8 @@ class PyBuildExt(build_ext): # uses modf(). self.add(Extension('_datetime', ['_datetimemodule.c'], libraries=['m'])) + # zoneinfo module + self.add(Extension('_zoneinfo', ['_zoneinfo.c'])), # random number generator implemented in C self.add(Extension("_random", ["_randommodule.c"], extra_compile_args=['-DPy_BUILD_CORE_MODULE'])) @@ -2495,6 +2508,7 @@ def main(): ProcessPoolExecutor = None sys.modules['concurrent.futures.process'] = DummyProcess + validate_tzpath() # turn off warnings when deprecated modules are imported import warnings