1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <string.h>
16 #include <cctype>
17 #include <cstdint>
18
19 #include "absl/time/internal/cctz/include/cctz/time_zone.h"
20 #include "absl/time/time.h"
21
22 namespace cctz = absl::time_internal::cctz;
23
24 namespace absl {
25 ABSL_NAMESPACE_BEGIN
26
27 ABSL_DLL extern const char RFC3339_full[] =
28 "%Y-%m-%dT%H:%M:%E*S%Ez";
29 ABSL_DLL extern const char RFC3339_sec[] = "%Y-%m-%dT%H:%M:%S%Ez";
30
31 ABSL_DLL extern const char RFC1123_full[] =
32 "%a, %d %b %E4Y %H:%M:%S %z";
33 ABSL_DLL extern const char RFC1123_no_wday[] =
34 "%d %b %E4Y %H:%M:%S %z";
35
36 namespace {
37
38 const char kInfiniteFutureStr[] = "infinite-future";
39 const char kInfinitePastStr[] = "infinite-past";
40
41 struct cctz_parts {
42 cctz::time_point<cctz::seconds> sec;
43 cctz::detail::femtoseconds fem;
44 };
45
unix_epoch()46 inline cctz::time_point<cctz::seconds> unix_epoch() {
47 return std::chrono::time_point_cast<cctz::seconds>(
48 std::chrono::system_clock::from_time_t(0));
49 }
50
51 // Splits a Time into seconds and femtoseconds, which can be used with CCTZ.
52 // Requires that 't' is finite. See duration.cc for details about rep_hi and
53 // rep_lo.
Split(absl::Time t)54 cctz_parts Split(absl::Time t) {
55 const auto d = time_internal::ToUnixDuration(t);
56 const int64_t rep_hi = time_internal::GetRepHi(d);
57 const int64_t rep_lo = time_internal::GetRepLo(d);
58 const auto sec = unix_epoch() + cctz::seconds(rep_hi);
59 const auto fem = cctz::detail::femtoseconds(rep_lo * (1000 * 1000 / 4));
60 return {sec, fem};
61 }
62
63 // Joins the given seconds and femtoseconds into a Time. See duration.cc for
64 // details about rep_hi and rep_lo.
Join(const cctz_parts & parts)65 absl::Time Join(const cctz_parts& parts) {
66 const int64_t rep_hi = (parts.sec - unix_epoch()).count();
67 const uint32_t rep_lo = parts.fem.count() / (1000 * 1000 / 4);
68 const auto d = time_internal::MakeDuration(rep_hi, rep_lo);
69 return time_internal::FromUnixDuration(d);
70 }
71
72 } // namespace
73
FormatTime(const std::string & format,absl::Time t,absl::TimeZone tz)74 std::string FormatTime(const std::string& format, absl::Time t,
75 absl::TimeZone tz) {
76 if (t == absl::InfiniteFuture()) return kInfiniteFutureStr;
77 if (t == absl::InfinitePast()) return kInfinitePastStr;
78 const auto parts = Split(t);
79 return cctz::detail::format(format, parts.sec, parts.fem,
80 cctz::time_zone(tz));
81 }
82
FormatTime(absl::Time t,absl::TimeZone tz)83 std::string FormatTime(absl::Time t, absl::TimeZone tz) {
84 return FormatTime(RFC3339_full, t, tz);
85 }
86
FormatTime(absl::Time t)87 std::string FormatTime(absl::Time t) {
88 return absl::FormatTime(RFC3339_full, t, absl::LocalTimeZone());
89 }
90
ParseTime(const std::string & format,const std::string & input,absl::Time * time,std::string * err)91 bool ParseTime(const std::string& format, const std::string& input,
92 absl::Time* time, std::string* err) {
93 return absl::ParseTime(format, input, absl::UTCTimeZone(), time, err);
94 }
95
96 // If the input string does not contain an explicit UTC offset, interpret
97 // the fields with respect to the given TimeZone.
ParseTime(const std::string & format,const std::string & input,absl::TimeZone tz,absl::Time * time,std::string * err)98 bool ParseTime(const std::string& format, const std::string& input,
99 absl::TimeZone tz, absl::Time* time, std::string* err) {
100 const char* data = input.c_str();
101 while (std::isspace(*data)) ++data;
102
103 size_t inf_size = strlen(kInfiniteFutureStr);
104 if (strncmp(data, kInfiniteFutureStr, inf_size) == 0) {
105 const char* new_data = data + inf_size;
106 while (std::isspace(*new_data)) ++new_data;
107 if (*new_data == '\0') {
108 *time = InfiniteFuture();
109 return true;
110 }
111 }
112
113 inf_size = strlen(kInfinitePastStr);
114 if (strncmp(data, kInfinitePastStr, inf_size) == 0) {
115 const char* new_data = data + inf_size;
116 while (std::isspace(*new_data)) ++new_data;
117 if (*new_data == '\0') {
118 *time = InfinitePast();
119 return true;
120 }
121 }
122
123 std::string error;
124 cctz_parts parts;
125 const bool b = cctz::detail::parse(format, input, cctz::time_zone(tz),
126 &parts.sec, &parts.fem, &error);
127 if (b) {
128 *time = Join(parts);
129 } else if (err != nullptr) {
130 *err = error;
131 }
132 return b;
133 }
134
135 // Functions required to support absl::Time flags.
AbslParseFlag(absl::string_view text,absl::Time * t,std::string * error)136 bool AbslParseFlag(absl::string_view text, absl::Time* t, std::string* error) {
137 return absl::ParseTime(RFC3339_full, std::string(text), absl::UTCTimeZone(),
138 t, error);
139 }
140
AbslUnparseFlag(absl::Time t)141 std::string AbslUnparseFlag(absl::Time t) {
142 return absl::FormatTime(RFC3339_full, t, absl::UTCTimeZone());
143 }
ParseFlag(const std::string & text,absl::Time * t,std::string * error)144 bool ParseFlag(const std::string& text, absl::Time* t, std::string* error) {
145 return absl::ParseTime(RFC3339_full, text, absl::UTCTimeZone(), t, error);
146 }
147
UnparseFlag(absl::Time t)148 std::string UnparseFlag(absl::Time t) {
149 return absl::FormatTime(RFC3339_full, t, absl::UTCTimeZone());
150 }
151
152 ABSL_NAMESPACE_END
153 } // namespace absl
154