Source code
Revision control
Copy as Markdown
Other Tools
// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/base/config.h"
#include "absl/time/internal/cctz/include/cctz/time_zone.h"
#if defined(__ANDROID__)
#include <sys/system_properties.h>
#if defined(__ANDROID_API__) && __ANDROID_API__ >= 21
#include <dlfcn.h>
#endif
#endif
#if defined(__APPLE__)
#include <CoreFoundation/CFTimeZone.h>
#include <vector>
#endif
#if defined(__Fuchsia__)
#include <fuchsia/intl/cpp/fidl.h>
#include <lib/async-loop/cpp/loop.h>
#include <lib/fdio/directory.h>
#include <zircon/types.h>
#endif
#if defined(_WIN32)
#include <sdkddkver.h>
// Include only when the SDK is for Windows 10 (and later), and the binary is
// targeted for Windows XP and later.
// Note: The Windows SDK added windows.globalization.h file for Windows 10, but
// MinGW did not add it until NTDDI_WIN10_NI (SDK version 10.0.22621.0).
#if ((defined(_WIN32_WINNT_WIN10) && !defined(__MINGW32__)) || \
(defined(NTDDI_WIN10_NI) && NTDDI_VERSION >= NTDDI_WIN10_NI)) && \
(_WIN32_WINNT >= _WIN32_WINNT_WINXP)
#define USE_WIN32_LOCAL_TIME_ZONE
#include <roapi.h>
#include <tchar.h>
#include <wchar.h>
#include <windows.globalization.h>
#include <windows.h>
#endif
#endif
#include <cstdlib>
#include <cstring>
#include <string>
#include "time_zone_fixed.h"
#include "time_zone_impl.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace time_internal {
namespace cctz {
namespace {
#if defined(__ANDROID__) && defined(__ANDROID_API__) && __ANDROID_API__ >= 21
// Android 'L' removes __system_property_get() from the NDK, however
// it is still a hidden symbol in libc so we use dlsym() to access it.
// See Chromium's base/sys_info_android.cc for a similar example.
using property_get_func = int (*)(const char*, char*);
property_get_func LoadSystemPropertyGet() {
int flag = RTLD_LAZY | RTLD_GLOBAL;
#if defined(RTLD_NOLOAD)
flag |= RTLD_NOLOAD; // libc.so should already be resident
#endif
if (void* handle = dlopen("libc.so", flag)) {
void* sym = dlsym(handle, "__system_property_get");
dlclose(handle);
return reinterpret_cast<property_get_func>(sym);
}
return nullptr;
}
int __system_property_get(const char* name, char* value) {
static property_get_func system_property_get = LoadSystemPropertyGet();
return system_property_get ? system_property_get(name, value) : -1;
}
#endif
#if defined(USE_WIN32_LOCAL_TIME_ZONE)
// Calls the WinRT Calendar.GetTimeZone method to obtain the IANA ID of the
// local time zone. Returns an empty vector in case of an error.
std::string win32_local_time_zone(const HMODULE combase) {
std::string result;
const auto ro_activate_instance =
reinterpret_cast<decltype(&RoActivateInstance)>(
GetProcAddress(combase, "RoActivateInstance"));
if (!ro_activate_instance) {
return result;
}
const auto windows_create_string_reference =
reinterpret_cast<decltype(&WindowsCreateStringReference)>(
GetProcAddress(combase, "WindowsCreateStringReference"));
if (!windows_create_string_reference) {
return result;
}
const auto windows_delete_string =
reinterpret_cast<decltype(&WindowsDeleteString)>(
GetProcAddress(combase, "WindowsDeleteString"));
if (!windows_delete_string) {
return result;
}
const auto windows_get_string_raw_buffer =
reinterpret_cast<decltype(&WindowsGetStringRawBuffer)>(
GetProcAddress(combase, "WindowsGetStringRawBuffer"));
if (!windows_get_string_raw_buffer) {
return result;
}
// The string returned by WindowsCreateStringReference doesn't need to be
// deleted.
HSTRING calendar_class_id;
HSTRING_HEADER calendar_class_id_header;
HRESULT hr = windows_create_string_reference(
RuntimeClass_Windows_Globalization_Calendar,
sizeof(RuntimeClass_Windows_Globalization_Calendar) / sizeof(wchar_t) - 1,
&calendar_class_id_header, &calendar_class_id);
if (FAILED(hr)) {
return result;
}
IInspectable* calendar;
hr = ro_activate_instance(calendar_class_id, &calendar);
if (FAILED(hr)) {
return result;
}
ABI::Windows::Globalization::ITimeZoneOnCalendar* time_zone;
hr = calendar->QueryInterface(IID_PPV_ARGS(&time_zone));
if (FAILED(hr)) {
calendar->Release();
return result;
}
HSTRING tz_hstr;
hr = time_zone->GetTimeZone(&tz_hstr);
if (SUCCEEDED(hr)) {
UINT32 wlen;
const PCWSTR tz_wstr = windows_get_string_raw_buffer(tz_hstr, &wlen);
if (tz_wstr) {
const int size =
WideCharToMultiByte(CP_UTF8, 0, tz_wstr, static_cast<int>(wlen),
nullptr, 0, nullptr, nullptr);
result.resize(static_cast<size_t>(size));
WideCharToMultiByte(CP_UTF8, 0, tz_wstr, static_cast<int>(wlen),
&result[0], size, nullptr, nullptr);
}
windows_delete_string(tz_hstr);
}
time_zone->Release();
calendar->Release();
return result;
}
#endif
} // namespace
std::string time_zone::name() const { return effective_impl().Name(); }
time_zone::absolute_lookup time_zone::lookup(
const time_point<seconds>& tp) const {
return effective_impl().BreakTime(tp);
}
time_zone::civil_lookup time_zone::lookup(const civil_second& cs) const {
return effective_impl().MakeTime(cs);
}
bool time_zone::next_transition(const time_point<seconds>& tp,
civil_transition* trans) const {
return effective_impl().NextTransition(tp, trans);
}
bool time_zone::prev_transition(const time_point<seconds>& tp,
civil_transition* trans) const {
return effective_impl().PrevTransition(tp, trans);
}
std::string time_zone::version() const { return effective_impl().Version(); }
std::string time_zone::description() const {
return effective_impl().Description();
}
const time_zone::Impl& time_zone::effective_impl() const {
if (impl_ == nullptr) {
// Dereferencing an implicit-UTC time_zone is expected to be
// rare, so we don't mind paying a small synchronization cost.
return *time_zone::Impl::UTC().impl_;
}
return *impl_;
}
bool load_time_zone(const std::string& name, time_zone* tz) {
return time_zone::Impl::LoadTimeZone(name, tz);
}
time_zone utc_time_zone() {
return time_zone::Impl::UTC(); // avoid name lookup
}
time_zone fixed_time_zone(const seconds& offset) {
time_zone tz;
load_time_zone(FixedOffsetToName(offset), &tz);
return tz;
}
time_zone local_time_zone() {
const char* zone = ":localtime";
#if defined(__ANDROID__)
char sysprop[PROP_VALUE_MAX];
if (__system_property_get("persist.sys.timezone", sysprop) > 0) {
zone = sysprop;
}
#endif
#if defined(__APPLE__)
std::vector<char> buffer;
CFTimeZoneRef tz_default = CFTimeZoneCopyDefault();
if (CFStringRef tz_name = CFTimeZoneGetName(tz_default)) {
CFStringEncoding encoding = kCFStringEncodingUTF8;
CFIndex length = CFStringGetLength(tz_name);
CFIndex max_size = CFStringGetMaximumSizeForEncoding(length, encoding) + 1;
buffer.resize(static_cast<size_t>(max_size));
if (CFStringGetCString(tz_name, &buffer[0], max_size, encoding)) {
zone = &buffer[0];
}
}
CFRelease(tz_default);
#endif
#if defined(__Fuchsia__)
std::string primary_tz;
[&]() {
// Note: We can't use the synchronous FIDL API here because it doesn't
// allow timeouts; if the FIDL call failed, local_time_zone() would never
// return.
const zx::duration kTimeout = zx::msec(500);
// Don't attach to the thread because otherwise the thread's dispatcher
// would be set to null when the loop is destroyed, causing any other FIDL
// code running on the same thread to crash.
async::Loop loop(&kAsyncLoopConfigNeverAttachToThread);
fuchsia::intl::PropertyProviderHandle handle;
zx_status_t status = fdio_service_connect_by_name(
fuchsia::intl::PropertyProvider::Name_,
handle.NewRequest().TakeChannel().release());
if (status != ZX_OK) {
return;
}
fuchsia::intl::PropertyProviderPtr intl_provider;
status = intl_provider.Bind(std::move(handle), loop.dispatcher());
if (status != ZX_OK) {
return;
}
intl_provider->GetProfile(
[&loop, &primary_tz](fuchsia::intl::Profile profile) {
if (!profile.time_zones().empty()) {
primary_tz = profile.time_zones()[0].id;
}
loop.Quit();
});
loop.Run(zx::deadline_after(kTimeout));
}();
if (!primary_tz.empty()) {
zone = primary_tz.c_str();
}
#endif
#if defined(USE_WIN32_LOCAL_TIME_ZONE)
// Use the WinRT Calendar class to get the local time zone. This feature is
// available on Windows 10 and later. The library is dynamically linked to
// maintain binary compatibility with Windows XP - Windows 7. On Windows 8,
// The combase.dll API functions are available but the RoActivateInstance
// call will fail for the Calendar class.
std::string winrt_tz;
const HMODULE combase =
LoadLibraryEx(_T("combase.dll"), nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32);
if (combase) {
const auto ro_initialize = reinterpret_cast<decltype(&::RoInitialize)>(
GetProcAddress(combase, "RoInitialize"));
const auto ro_uninitialize = reinterpret_cast<decltype(&::RoUninitialize)>(
GetProcAddress(combase, "RoUninitialize"));
if (ro_initialize && ro_uninitialize) {
const HRESULT hr = ro_initialize(RO_INIT_MULTITHREADED);
// RPC_E_CHANGED_MODE means that a previous RoInitialize call specified
// a different concurrency model. The WinRT runtime is initialized and
// should work for our purpose here, but we should *not* call
// RoUninitialize because it's a failure.
if (SUCCEEDED(hr) || hr == RPC_E_CHANGED_MODE) {
winrt_tz = win32_local_time_zone(combase);
if (SUCCEEDED(hr)) {
ro_uninitialize();
}
}
}
FreeLibrary(combase);
}
if (!winrt_tz.empty()) {
zone = winrt_tz.c_str();
}
#endif
// Allow ${TZ} to override to default zone.
char* tz_env = nullptr;
#if defined(_MSC_VER)
_dupenv_s(&tz_env, nullptr, "TZ");
#else
tz_env = std::getenv("TZ");
#endif
if (tz_env) zone = tz_env;
// We only support the "[:]<zone-name>" form.
if (*zone == ':') ++zone;
// Map "localtime" to a system-specific name, but
// allow ${LOCALTIME} to override the default name.
char* localtime_env = nullptr;
if (strcmp(zone, "localtime") == 0) {
#if defined(_MSC_VER)
// System-specific default is just "localtime".
_dupenv_s(&localtime_env, nullptr, "LOCALTIME");
#else
zone = "/etc/localtime"; // System-specific default.
localtime_env = std::getenv("LOCALTIME");
#endif
if (localtime_env) zone = localtime_env;
}
const std::string name = zone;
#if defined(_MSC_VER)
free(localtime_env);
free(tz_env);
#endif
time_zone tz;
load_time_zone(name, &tz); // Falls back to UTC.
// TODO: Follow the RFC3339 "Unknown Local Offset Convention" and
// arrange for %z to generate "-0000" when we don't know the local
// offset because the load_time_zone() failed and we're using UTC.
return tz;
}
} // namespace cctz
} // namespace time_internal
ABSL_NAMESPACE_END
} // namespace absl