hare

commit 6b464c4043c8215cb409b97e0befc474cf6d6458
parent 1dceb79502fafeaeb4cd94dc584884d23ffe50c9
Author: Byron Torres <b@torresjrjr.com>
Date:   Tue, 24 May 2022 04:00:21 +0100

time::chrono: fix LOCAL init, improve docs

Renamed TZ_local to TZ_LOCAL. Consistent and less ungly, I suppose.

Improved docs for [[TZ_LOCAL]].

TZ_LOCAL.name now defaults to "Local". [[timezone]].name is meant to be
an identifier, rather than descriptive or end-user-friendly, and there's
a convention or unwritten rule to keep them whitespace-less for this
purpose. This convention is (will be) useful when parsing %L. Perhaps we
should add a .description field.

The filepath of the TZif file, if appropriate, is now used as part of
the name for [[TZ_LOCAL]].

Signed-off-by: Byron Torres <b@torresjrjr.com>

Diffstat:
M
time/chrono/timezone.ha
 | 
66
++++++++++++++++++++++++++++++++++++++++++------------------------

1 file changed, 42 insertions(+), 24 deletions(-)
diff --git a/time/chrono/timezone.ha b/time/chrono/timezone.ha
@@ -4,6 +4,7 @@ use bufio;
 use io;
 use os;
 use path;
+use strings;
 use time;
 
 // The locality of a [[moment]]. Contains information about how to present a
@@ -167,50 +168,67 @@ export fn fixedzone(ts: *timescale, daylen: time::duration, z: zone) timezone = 
 
 // The system's [[locality]]; the system's local [[timezone]].
 //
-// This is set during initialisation.
-export const LOCAL: locality = &TZ_local;
+// This is set during a program's initialisation, where the TZ environment
+// variable is tried, otherwise the /etc/localtime file is tried, otherwise a
+// default is used.
+//
+// The default timezone is equivalent to that of [[UTC]], with "Local" being the
+// name of both the timezone and its single zero-offset zone.
+export const LOCAL: locality = &TZ_LOCAL;
+
+let TZ_LOCAL: timezone = timezone {
+	name = "Local",
+	timescale = &utc,
+	daylength = EARTH_DAY,
+	zones = [
+		zone {
+			zoffset = 0 * time::SECOND,
+			name = "Local",
+			abbr = "",
+			dst = false,
+		},
+	],
+	transitions = [],
+	posix_extend = "",
+};
 
 @init fn set_local_timezone() void = {
 	match (os::getenv("TZ")) {
 	case let zone: str =>
-		TZ_local = match (tz(zone)) {
+		TZ_LOCAL = match (tz(zone)) {
 		case let tz: timezone =>
 			yield tz;
 		case =>
 			return;
 		};
 	case void =>
-		const file = match (os::open(LOCALTIME_PATH)) {
-		case let file: io::file =>
-			yield file;
+		const filepath = match (os::readlink(LOCALTIME_PATH)) {
+		case let fp: str =>
+			yield fp;
+		case =>
+			return;
+		};
+
+		const file = match (os::open(filepath)) {
+		case let f: io::file =>
+			yield f;
 		case =>
 			return;
 		};
 		defer io::close(file)!;
 
+		if (strings::hasprefix(filepath, ZONEINFO_PREFIX)) {
+			TZ_LOCAL.name = strings::trimprefix(
+				filepath, ZONEINFO_PREFIX,
+			);
+		};
+
 		static let buf: [os::BUFSIZ]u8 = [0...];
 		const file = bufio::buffered(file, buf, []);
-
-		match (parse_tzif(&file, &TZ_local)) { case => void; };
+		match (parse_tzif(&file, &TZ_LOCAL)) { case => void; };
 	};
 };
 
-let TZ_local: timezone = timezone {
-	name = "Local time",
-	timescale = &utc,
-	daylength = EARTH_DAY,
-	zones = [
-		zone {
-			zoffset = 0 * time::SECOND,
-			name = "Local time",
-			abbr = "",
-			dst = false,
-		},
-	],
-	transitions = [],
-	posix_extend = "",
-};
-
 // The UTC (Coordinated Universal Time) "Zulu" [[timezone]] as a [[locality]].
 export const UTC: locality = &TZ_UTC;