1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
// 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
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// 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 "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
#include <cstdlib>
#include <cstring>
#include <string>
#include "time_zone_fixed.h"
#include "time_zone_impl.h"
namespace cctz {
#if defined(__ANDROID__) && defined(__ANDROID_API__) && __ANDROID_API__ >= 21
namespace {
// 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;
}
} // namespace
#endif
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);
buffer.resize(CFStringGetMaximumSizeForEncoding(length, encoding) + 1);
if (CFStringGetCString(tz_name, &buffer[0], buffer.size(), encoding)) {
zone = &buffer[0];
}
}
CFRelease(tz_default);
#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
|
