LibTimeZone: Add methods to canonicalize a time zone name

lanmonster · Jan 10, 2022 · e9c42d0 · e9c42d0
1 parent 1c2c98a
commit e9c42d0
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Showing 3 changed files with 29 additions and 0 deletions.
diff --git a/Tests/LibTimeZone/TestTimeZone.cpp b/Tests/LibTimeZone/TestTimeZone.cpp
@@ -69,4 +69,19 @@ TEST_CASE(time_zone_to_string_link)
  EXPECT_EQ(TimeZone::time_zone_to_string(TimeZone::TimeZone::Etc_Universal), "Etc/UTC"sv);
 }
 
+TEST_CASE(canonicalize_time_zone)
+{
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("America/New_York"sv), "America/New_York"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("AmErIcA/NeW_YoRk"sv), "America/New_York"sv);
+
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("UTC"sv), "UTC"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("GMT"sv), "UTC"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("GMT+0"sv), "UTC"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("GMT-0"sv), "UTC"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("Etc/UTC"sv), "UTC"sv);
+ EXPECT_EQ(TimeZone::canonicalize_time_zone("Etc/GMT"sv), "UTC"sv);
+
+ EXPECT(!TimeZone::canonicalize_time_zone("I don't exist"sv).has_value());
+}
+
 #endif
diff --git a/Userland/Libraries/LibTimeZone/TimeZone.cpp b/Userland/Libraries/LibTimeZone/TimeZone.cpp
@@ -11,4 +11,17 @@ namespace TimeZone {
 Optional<TimeZone> __attribute__((weak)) time_zone_from_string(StringView) { return {}; }
 StringView __attribute__((weak)) time_zone_to_string(TimeZone) { return {}; }
 
+Optional<StringView> canonicalize_time_zone(StringView time_zone)
+{
+ auto maybe_time_zone = time_zone_from_string(time_zone);
+ if (!maybe_time_zone.has_value())
+ return {};
+
+ auto canonical_time_zone = time_zone_to_string(*maybe_time_zone);
+ if (canonical_time_zone.is_one_of("Etc/UTC"sv, "Etc/GMT"sv))
+ return "UTC"sv;
+
+ return canonical_time_zone;
+}
+
 }
diff --git a/Userland/Libraries/LibTimeZone/TimeZone.h b/Userland/Libraries/LibTimeZone/TimeZone.h
@@ -14,5 +14,6 @@ namespace TimeZone {
 
 Optional<TimeZone> time_zone_from_string(StringView time_zone);
 StringView time_zone_to_string(TimeZone time_zone);
+Optional<StringView> canonicalize_time_zone(StringView time_zone);
 
 }