pkg/time: define time types and builtins
based on Go package.
These result in more accurate parsing and make
it easier to track the time type.
Change-Id: Iff75afc905dd9d0af58d1ea76db92a9d351a5d50
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2720
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/pkg/time/duration.go b/pkg/time/duration.go
new file mode 100644
index 0000000..3146937
--- /dev/null
+++ b/pkg/time/duration.go
@@ -0,0 +1,65 @@
+// Copyright 2019 CUE Authors
+//
+// 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
+//
+// http://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.
+
+package time
+
+import (
+ "time"
+)
+
+// Common durations. There is no definition for units of Day or larger
+// to avoid confusion across daylight savings time zone transitions.
+//
+// To count the number of units in a Duration, divide:
+// second := time.Second
+// fmt.Print(int64(second/time.Millisecond)) // prints 1000
+//
+// To convert an integer number of units to a Duration, multiply:
+// seconds := 10
+// fmt.Print(time.Duration(seconds)*time.Second) // prints 10s
+//
+const (
+ Nanosecond = 1
+ Microsecond = 1000
+ Millisecond = 1000000
+ Second = 1000000000
+ Minute = 60000000000
+ Hour = 3600000000000
+)
+
+// Duration validates a duration string.
+//
+// Note: this format also accepts strings of the form '1h3m', '2ms', etc.
+// To limit this to seconds only, as often used in JSON, add the !~"hmuµn"
+// constraint.
+func Duration(s string) (bool, error) {
+ if _, err := time.ParseDuration(s); err != nil {
+ return false, err
+ }
+ return true, nil
+}
+
+// ParseDuration reports the nanoseconds represented by a duration string.
+//
+// A duration string is a possibly signed sequence of
+// decimal numbers, each with optional fraction and a unit suffix,
+// such as "300ms", "-1.5h" or "2h45m".
+// Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+func ParseDuration(s string) (int64, error) {
+ d, err := time.ParseDuration(s)
+ if err != nil {
+ return 0, err
+ }
+ return int64(d), nil
+}
