time: revise for go1.12

Update #3

Author: changkun

gosrc/1.11.5/time/format.go

@@ -1120,7 +1120,8 @@ func parseTimeZone(value string) (length int, ok bool) {
 	// Special Case 3: Some time zones are not named, but have +/-00 format
 	if value[0] == '+' || value[0] == '-' {
 		length = parseSignedOffset(value)
-		return length, true
+		ok := length > 0 // parseSignedOffset returns 0 in case of bad input
+		return length, ok
 	}
 	// How many upper-case letters are there? Need at least three, at most five.
 	var nUpper int
@@ -1152,7 +1153,7 @@ func parseTimeZone(value string) (length int, ok bool) {
 
 // parseGMT parses a GMT time zone. The input string is known to start "GMT".
 // The function checks whether that is followed by a sign and a number in the
-// range -14 through 12 excluding zero.
+// range -23 through +23 excluding zero.
 func parseGMT(value string) int {
 	value = value[3:]
 	if len(value) == 0 {
@@ -1163,21 +1164,23 @@ func parseGMT(value string) int {
 }
 
 // parseSignedOffset parses a signed timezone offset (e.g. "+03" or "-04").
-// The function checks for a signed number in the range -14 through +12 excluding zero.
+// The function checks for a signed number in the range -23 through +23 excluding zero.
 // Returns length of the found offset string or 0 otherwise
 func parseSignedOffset(value string) int {
 	sign := value[0]
 	if sign != '-' && sign != '+' {
 		return 0
 	}
 	x, rem, err := leadingInt(value[1:])
-	if err != nil {
+
+	// fail if nothing consumed by leadingInt
+	if err != nil || value[1:] == rem {
 		return 0
 	}
 	if sign == '-' {
 		x = -x
 	}
-	if x == 0 || x < -14 || 12 < x {
+	if x < -23 || 23 < x {
 		return 0
 	}
 	return len(value) - len(rem)

gosrc/1.11.5/time/sleep.go

@@ -8,9 +8,6 @@ package time
 // A negative or zero duration causes Sleep to return immediately.
 func Sleep(d Duration)
 
-// runtimeNano returns the current value of the runtime clock in nanoseconds.
-func runtimeNano() int64
-
 // Interface to timers implemented in package runtime.
 // Must be in sync with ../runtime/time.go:/^type timer
 type runtimeTimer struct {

gosrc/1.11.5/time/sys_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package time
 

gosrc/1.11.5/time/time.go

@@ -75,7 +75,10 @@
 //
 package time
 
-import "errors"
+import (
+	"errors"
+	_ "unsafe" // for go:linkname
+)
 
 // A Time represents an instant in time with nanosecond precision.
 //
@@ -102,6 +105,10 @@ import "errors"
 // change the instant in time being denoted and therefore does not affect the
 // computations described in earlier paragraphs.
 //
+// Representations of a Time value saved by the GobEncode, MarshalBinary,
+// MarshalJSON, and MarshalText methods store the Time.Location's offset, but not
+// the location name. They therefore lose information about Daylight Saving Time.
+//
 // In addition to the required “wall clock” reading, a Time may contain an optional
 // reading of the current process's monotonic clock, to provide additional precision
 // for comparison or subtraction.
@@ -908,13 +915,27 @@ func (t Time) Sub(u Time) Duration {
 // Since returns the time elapsed since t.
 // It is shorthand for time.Now().Sub(t).
 func Since(t Time) Duration {
-	return Now().Sub(t)
+	var now Time
+	if t.wall&hasMonotonic != 0 {
+		// Common case optimization: if t has monotomic time, then Sub will use only it.
+		now = Time{hasMonotonic, runtimeNano() - startNano, nil}
+	} else {
+		now = Now()
+	}
+	return now.Sub(t)
 }
 
 // Until returns the duration until t.
 // It is shorthand for t.Sub(time.Now()).
 func Until(t Time) Duration {
-	return t.Sub(Now())
+	var now Time
+	if t.wall&hasMonotonic != 0 {
+		// Common case optimization: if t has monotomic time, then Sub will use only it.
+		now = Time{hasMonotonic, runtimeNano() - startNano, nil}
+	} else {
+		now = Now()
+	}
+	return t.Sub(now)
 }
 
 // AddDate returns the time corresponding to adding the
@@ -933,7 +954,7 @@ func (t Time) AddDate(years int, months int, days int) Time {
 
 const (
 	secondsPerMinute = 60
-	secondsPerHour   = 60 * 60
+	secondsPerHour   = 60 * secondsPerMinute
 	secondsPerDay    = 24 * secondsPerHour
 	secondsPerWeek   = 7 * secondsPerDay
 	daysPer400Years  = 365*400 + 97
@@ -1050,9 +1071,22 @@ func daysIn(m Month, year int) int {
 // Provided by package runtime.
 func now() (sec int64, nsec int32, mono int64)
 
+// runtimeNano returns the current value of the runtime clock in nanoseconds.
+//go:linkname runtimeNano runtime.nanotime
+func runtimeNano() int64
+
+// Monotonic times are reported as offsets from startNano.
+// We initialize startNano to runtimeNano() - 1 so that on systems where
+// monotonic time resolution is fairly low (e.g. Windows 2008
+// which appears to have a default resolution of 15ms),
+// we avoid ever reporting a monotonic time of 0.
+// (Callers may want to use 0 as "time not set".)
+var startNano int64 = runtimeNano() - 1
+
 // Now returns the current local time.
 func Now() Time {
 	sec, nsec, mono := now()
+	mono -= startNano
 	sec += unixToInternal - minWall
 	if uint64(sec)>>33 != 0 {
 		return Time{uint64(nsec), sec + minWall, Local}
@@ -1076,7 +1110,7 @@ func (t Time) Local() Time {
 	return t
 }
 
-// In returns a copy of t representating the same time instant, but
+// In returns a copy of t representing the same time instant, but
 // with the copy's location information set to loc for display
 // purposes.
 //

gosrc/1.11.5/time/zoneinfo.go

@@ -205,7 +205,7 @@ func (l *Location) lookupFirstZone() int {
 	return 0
 }
 
-// firstZoneUsed returns whether the first zone is used by some
+// firstZoneUsed reports whether the first zone is used by some
 // transition.
 func (l *Location) firstZoneUsed() bool {
 	for _, tx := range l.tx {
@@ -288,14 +288,23 @@ func LoadLocation(name string) (*Location, error) {
 		env, _ := syscall.Getenv("ZONEINFO")
 		zoneinfo = &env
 	})
+	var firstErr error
 	if *zoneinfo != "" {
 		if zoneData, err := loadTzinfoFromDirOrZip(*zoneinfo, name); err == nil {
 			if z, err := LoadLocationFromTZData(name, zoneData); err == nil {
 				return z, nil
 			}
+			firstErr = err
+		} else if err != syscall.ENOENT {
+			firstErr = err
 		}
 	}
-	return loadLocation(name, zoneSources)
+	if z, err := loadLocation(name, zoneSources); err == nil {
+		return z, nil
+	} else if firstErr == nil {
+		firstErr = err
+	}
+	return nil, firstErr
 }
 
 // containsDotDot reports whether s contains "..".

gosrc/1.11.5/time/zoneinfo_read.go

@@ -11,6 +11,7 @@ package time
 
 import (
 	"errors"
+	"runtime"
 	"syscall"
 )
 
@@ -55,7 +56,7 @@ func (d *dataIO) big4() (n uint32, ok bool) {
 		d.error = true
 		return 0, false
 	}
-	return uint32(p[0])<<24 | uint32(p[1])<<16 | uint32(p[2])<<8 | uint32(p[3]), true
+	return uint32(p[3]) | uint32(p[2])<<8 | uint32(p[1])<<16 | uint32(p[0])<<24, true
 }
 
 func (d *dataIO) byte() (n byte, ok bool) {
@@ -172,6 +173,14 @@ func LoadLocationFromTZData(name string, data []byte) (*Location, error) {
 			return nil, badData
 		}
 		zone[i].name = byteString(abbrev[b:])
+		if runtime.GOOS == "aix" && len(name) > 8 && (name[:8] == "Etc/GMT+" || name[:8] == "Etc/GMT-") {
+			// There is a bug with AIX 7.2 TL 0 with files in Etc,
+			// GMT+1 will return GMT-1 instead of GMT+1 or -01.
+			if name != "Etc/GMT+0" {
+				// GMT+0 is OK
+				zone[i].name = name[4:]
+			}
+		}
 	}
 
 	// Now the transition time info.
@@ -262,7 +271,7 @@ func get2(b []byte) int {
 func loadTzinfoFromZip(zipfile, name string) ([]byte, error) {
 	fd, err := open(zipfile)
 	if err != nil {
-		return nil, errors.New("open " + zipfile + ": " + err.Error())
+		return nil, err
 	}
 	defer closefd(fd)
 
@@ -364,7 +373,7 @@ func loadTzinfoFromZip(zipfile, name string) ([]byte, error) {
 		return buf, nil
 	}
 
-	return nil, errors.New("cannot find " + name + " in zip file " + zipfile)
+	return nil, syscall.ENOENT
 }
 
 // loadTzinfoFromTzdata returns the time zone information of the time zone

gosrc/1.11.5/time/zoneinfo_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin,386 darwin,amd64 dragonfly freebsd js,wasm linux,!android nacl netbsd openbsd solaris
+// +build aix darwin,386 darwin,amd64 dragonfly freebsd linux,!android nacl netbsd openbsd solaris
 
 // Parse "zoneinfo" time zone file.
 // This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.