Rename Instant.offsetAt(TZ) -> offsetIn, introduce TimeZone.offsetAt(Instant)

Author: ilya-g

core/commonMain/src/TimeZone.kt

@@ -40,14 +40,16 @@ public expect class ZoneOffset : TimeZone {
     val totalSeconds: Int
 }
 
+public fun TimeZone.offsetAt(instant: Instant): ZoneOffset =
+        instant.offsetIn(this) // TODO: make the other way around
 
 /**
  * @throws DateTimeArithmeticException if this value is too large to fit in [LocalDateTime].
  */
 public expect fun Instant.toLocalDateTime(timeZone: TimeZone): LocalDateTime
 
 /** */
-public expect fun Instant.offsetAt(timeZone: TimeZone): ZoneOffset
+public expect fun Instant.offsetIn(timeZone: TimeZone): ZoneOffset
 
 /** */
 public expect fun LocalDateTime.toInstant(timeZone: TimeZone): Instant

core/commonTest/src/InstantTest.kt

@@ -182,20 +182,20 @@ class InstantTest {
         val zone = TimeZone.of("Europe/Berlin")
         val instant1 = LocalDateTime(2019, 10, 27, 2, 59, 0, 0).toInstant(zone)
         val ldt1 = instant1.toLocalDateTime(zone)
-        val offset1 = instant1.offsetAt(zone)
+        val offset1 = instant1.offsetIn(zone)
         checkComponents(ldt1, 2019, 10, 27, 2, 59)
         assertEquals(instant1, ldt1.toInstant(offset1))
 
         val instant2 = instant1 + 1.hours
         val ldt2 = instant2.toLocalDateTime(zone)
-        val offset2 = instant2.offsetAt(zone)
+        val offset2 = instant2.offsetIn(zone)
         assertEquals(ldt1, ldt2)
         assertEquals(instant2, ldt2.toInstant(offset2))
         assertNotEquals(offset1, offset2)
         assertEquals(offset1.totalSeconds.seconds, offset2.totalSeconds.seconds + 1.hours)
 
         val instant3 = instant2 - 2.hours
-        val offset3 = instant3.offsetAt(zone)
+        val offset3 = instant3.offsetIn(zone)
         assertEquals(offset1, offset3)
     }
 

core/commonTest/src/TimeZoneTest.kt

@@ -22,7 +22,7 @@ class TimeZoneTest {
     fun system() {
         val tz = TimeZone.currentSystemDefault()
         println(tz)
-        val offset = Clock.System.now().offsetAt(tz)
+        val offset = Clock.System.now().offsetIn(tz)
         assertTrue(offset.totalSeconds in -18 * 60 * 60 .. 18 * 60 * 60)
         // assertTrue(tz.id.contains('/')) // does not work on build agents, whose timezone is "UTC"
         // TODO: decide how to assert system tz properties

core/jsMain/src/TimeZone.kt

@@ -13,7 +13,7 @@ actual open class TimeZone internal constructor(internal val zoneId: ZoneId) {
 
     // experimental member-extensions
     public actual fun Instant.toLocalDateTime(): LocalDateTime = toLocalDateTime(this@TimeZone)
-    public actual val Instant.offset: ZoneOffset get() = offsetAt(this@TimeZone)
+    public actual val Instant.offset: ZoneOffset get() = offsetIn(this@TimeZone)
     public actual fun LocalDateTime.toInstant(): Instant = toInstant(this@TimeZone)
 
     override fun equals(other: Any?): Boolean =
@@ -52,7 +52,7 @@ public actual fun Instant.toLocalDateTime(timeZone: TimeZone): LocalDateTime = t
     throw e
 }
 
-public actual fun Instant.offsetAt(timeZone: TimeZone): ZoneOffset =
+public actual fun Instant.offsetIn(timeZone: TimeZone): ZoneOffset =
         timeZone.zoneId.rules().offsetOfInstant(this.value).let(::ZoneOffset)
 
 public actual fun LocalDateTime.toInstant(timeZone: TimeZone): Instant =

core/jvmMain/src/TimeZone.kt

@@ -15,7 +15,7 @@ actual open class TimeZone internal constructor(internal val zoneId: ZoneId) {
 
     // experimental member-extensions
     public actual fun Instant.toLocalDateTime(): LocalDateTime = toLocalDateTime(this@TimeZone)
-    public actual val Instant.offset: ZoneOffset get() = offsetAt(this@TimeZone)
+    public actual val Instant.offset: ZoneOffset get() = offsetIn(this@TimeZone)
     public actual fun LocalDateTime.toInstant(): Instant = toInstant(this@TimeZone)
 
     override fun equals(other: Any?): Boolean =
@@ -54,7 +54,7 @@ public actual fun Instant.toLocalDateTime(timeZone: TimeZone): LocalDateTime = t
     throw DateTimeArithmeticException(e)
 }
 
-public actual fun Instant.offsetAt(timeZone: TimeZone): ZoneOffset =
+public actual fun Instant.offsetIn(timeZone: TimeZone): ZoneOffset =
         timeZone.zoneId.rules.getOffset(this.value).let(::ZoneOffset)
 
 public actual fun LocalDateTime.toInstant(timeZone: TimeZone): Instant =

core/nativeMain/src/TimeZone.kt

@@ -289,7 +289,7 @@ public actual fun Instant.toLocalDateTime(timeZone: TimeZone): LocalDateTime =
 public actual fun LocalDateTime.toInstant(timeZone: TimeZone): Instant =
         with(timeZone) { toInstant() }
 
-public actual fun Instant.offsetAt(timeZone: TimeZone): ZoneOffset =
+public actual fun Instant.offsetIn(timeZone: TimeZone): ZoneOffset =
         with(timeZone) { offset }
 
 public actual fun LocalDate.atStartOfDayIn(timeZone: TimeZone): Instant =