go/human/human.go - buildbot - Git at Google

 // Package human provides human friendly display formats.
 package human

 import (
 	"fmt"
 	"math"
 	"regexp"
 	"strconv"
 	"strings"
 	"time"

 	"go.skia.org/infra/go/sklog"
 )

 const MIN_TICKS = 2

 // TimeOp is a function that given a time will return a string that would be a
 // good label for that time.
 type TimeOp func(time.Time) string

 // choices is the list of hour increments and associated TimeOps for those
 // durations, sorted from largest to smallest hour duration.
 var choices = []struct {
 	Duration time.Duration
 	Op       TimeOp
 }{
 	{24 * 7 * 4 * time.Hour, func(t time.Time) string { return t.Format("Jan") }},             // Month
 	{24 * 3 * time.Hour, func(t time.Time) string { return t.Format("2") + suffix(t.Day()) }}, // Day of month
 	{24 * time.Hour, func(t time.Time) string { return t.Format("Mon") }},                     // Weekdays
 	{2 * time.Hour, func(t time.Time) string { return t.Format("3pm") }},                      // Hours
 	{2 * time.Minute, func(t time.Time) string { return t.Format("03:04pm") }},                // Minutes
 	{2 * time.Second, func(t time.Time) string { return t.Format("03:04:05pm") }},             // Seconds
 }

 // suffix returns the correct suffix for a day number.
 //
 // For making human friendly dates:
 //
 //  1st, 2nd, 3rd, etc.
 //
 func suffix(day int) string {
 	// The rules are pretty simple, everything ends in "th", except numbers that
 	// end in 1, 2 or 3 which end in "st", "nd" and "rd" respectively. The only
 	// exceptions are the teens (10 - 19) which always end in "th".
 	if day >= 4 && day <= 20 {
 		return "th"
 	} else if day%10 == 1 {
 		return "st"
 	} else if day%10 == 2 {
 		return "nd"
 	} else if day%10 == 3 {
 		return "rd"
 	}
 	return "th"
 }

 // opFromHours takes a number of hours and from that returns a function that
 // will produce good labels for tick marks in that time range. For example, if
 // the time range is small enough then the ticks will be marked with the
 // weekday, e.g.  "Sun", if the time range is much larger the ticks may be
 // marked with the month, e.g. "Jul".
 func opFromHours(duration time.Duration) (TimeOp, error) {
 	// Move down the list of choices from the largest granularity to the finest.
 	// The first one that would generate more than MIN_TICKS for the given number
 	// of hours is chosen and that TimeOp is returned.
 	var Op TimeOp = nil
 	for _, c := range choices {
 		if duration > c.Duration {
 			Op = c.Op
 			break
 		}
 	}
 	if Op == nil {
 		return nil, fmt.Errorf("Couldn't calculate TimeOp")
 	}
 	return Op, nil
 }

 // Tick represents a single tick mark.
 type Tick struct {
 	X     float64
 	Value string
 }

 // ToFlot converts a slice of Ticks into something that will serialize into
 // JSON that Flot consumes, which is an array of 2 element arrays. The 2 element
 // arrays contain an x offset and then a label as a string. For example:
 //
 //   [ [ 0.5, "Saturday" ], [ 1.5, "Sunday" ] ]
 //
 func ToFlot(ticks []*Tick) []interface{} {
 	ret := []interface{}{}
 	for _, t := range ticks {
 		ret = append(ret, []interface{}{t.X, t.Value})
 	}
 	return ret
 }

 // TickMarks produces human readable tickmarks to span the given timestamps.
 //
 // The array of timestamps are presumed to be in ascending order.
 // If 'in' is nil then the "Local" time zone is used.
 //
 // The choice of how to label the tick marks is based on the full time
 // range of the timestamps.
 func TickMarks(timestamps []int64, in *time.Location) []*Tick {
 	loc := in
 	if loc == nil {
 		var err error
 		loc, err = time.LoadLocation("Local")
 		if err != nil {
 			loc = time.UTC
 		}
 	}
 	ret := []*Tick{}
 	if len(timestamps) < 2 {
 		sklog.Warningf("Insufficient number of commits: %d", len(timestamps))
 		return ret
 	}

 	begin := time.Unix(timestamps[0], 0).In(loc)
 	end := time.Unix(timestamps[len(timestamps)-1], 0).In(loc)
 	duration := end.Sub(begin)
 	op, err := opFromHours(duration)
 	if err != nil {
 		sklog.Errorf("Failed to calculate tickmarks for: %s %s: %s", begin, end, err)
 		return ret
 	}
 	last := op(begin)
 	ret = append(ret, &Tick{X: 0, Value: last})
 	for i, t := range timestamps {
 		if tickValue := op(time.Unix(t, 0).In(loc)); last != tickValue {
 			last = tickValue
 			ret = append(ret, &Tick{X: float64(i) - 0.5, Value: tickValue})
 		}
 	}

 	return ret
 }

 // FlotTickMarks returns a struct that will serialize into JSON that Flot
 // expects for a value for tick marks.
 //
 // If an error occurs the tick list will be empty.
 //
 // tz is the timezone, and can be the empty string if the default (Eastern) timezone is acceptable.
 func FlotTickMarks(ts []int64, tz string) []interface{} {
 	if tz == "" {
 		tz = "America/New_York"
 	}
 	loc, err := time.LoadLocation(tz)
 	if err != nil {
 		loc, err = time.LoadLocation("UTC")
 		if err != nil {
 			sklog.Errorf("Failed to load the timezone %q: %s", tz, err)
 			return []interface{}{}
 		}
 	}
 	return ToFlot(TickMarks(ts, loc))
 }

 var durationRe = regexp.MustCompile("([0-9]+)([smhdw])$")

 // ParseDuration parses a human readable duration. Note that this understands
 // both days and weeks, which time.ParseDuration does not support.
 func ParseDuration(s string) (time.Duration, error) {
 	parsed := durationRe.FindStringSubmatch(s)
 	if len(parsed) != 3 {
 		return time.Duration(0), fmt.Errorf("Invalid format: %s", s)
 	}
 	n, err := strconv.ParseInt(parsed[1], 10, 32)
 	if err != nil {
 		return time.Duration(0), fmt.Errorf("Invalid numeric format: %s", s)
 	}
 	d := time.Second
 	switch parsed[2][0] {
 	case 's':
 		d = time.Duration(n) * time.Second
 	case 'm':
 		d = time.Duration(n) * time.Minute
 	case 'h':
 		d = time.Duration(n) * time.Hour
 	case 'd':
 		d = time.Duration(n) * 24 * time.Hour
 	case 'w':
 		d = time.Duration(n) * 7 * 24 * time.Hour
 	}
 	return d, nil
 }

 type delta struct {
 	units string
 	delta int64
 }

 var (
 	deltas = []delta{
 		{
 			units: "y",
 			delta: 365 * 24 * 60 * 60,
 		},
 		{
 			units: "w",
 			delta: 7 * 24 * 60 * 60,
 		},
 		{
 			units: "d",
 			delta: 24 * 60 * 60,
 		},
 		{
 			units: "h",
 			delta: 60 * 60,
 		},
 		{
 			units: "m",
 			delta: 60,
 		},
 		{
 			units: "s",
 			delta: 1,
 		},
 	}
 )

 // Duration returns a human friendly description of the given time.Duration.
 //
 // For example Duration(61*time.Second) returns " 1m 1s".
 //
 // The length of the string returned is guaranteed to always be 7.
 // A negative duration is treated the same as a positive duration.
 func Duration(duration time.Duration) string {
 	ret := []string{}
 	s := int64(math.Abs(duration.Seconds()))
 	for _, d := range deltas {
 		if d.delta <= s {
 			ret = append(ret, fmt.Sprintf("%2d%s", s/d.delta, d.units))
 			s = s % d.delta
 			if len(ret) == 2 {
 				break
 			}
 		}
 	}
 	if len(ret) == 0 {
 		ret = append(ret, "   ", " 0s")
 	}
 	if len(ret) < 2 {
 		ret = []string{"   ", ret[0]}
 	}
 	return strings.Join(ret, " ")
 }

 // JSONDuration is a type that implements the json.Unmarshal interface and can be used
 // to parse human readable durations from configuration files.
 type JSONDuration time.Duration

 func (d *JSONDuration) String() string {
 	return strings.TrimSpace(Duration(time.Duration(*d)))
 }

 func (d *JSONDuration) UnmarshalJSON(durBytes []byte) error {
 	durStr := strings.Trim(string(durBytes), "\"")
 	duration, err := ParseDuration(string(durStr))
 	if err != nil {
 		return err
 	}
 	*d = JSONDuration(duration)
 	return nil
 }
	// Package human provides human friendly display formats.
	package human

	import (
	"fmt"
	"math"
	"regexp"
	"strconv"
	"strings"
	"time"

	"go.skia.org/infra/go/sklog"
	)

	const MIN_TICKS = 2

	// TimeOp is a function that given a time will return a string that would be a
	// good label for that time.
	type TimeOp func(time.Time) string

	// choices is the list of hour increments and associated TimeOps for those
	// durations, sorted from largest to smallest hour duration.
	var choices = []struct {
	Duration time.Duration
	Op TimeOp
	}{
	{24 * 7 * 4 * time.Hour, func(t time.Time) string { return t.Format("Jan") }}, // Month
	{24 * 3 * time.Hour, func(t time.Time) string { return t.Format("2") + suffix(t.Day()) }}, // Day of month
	{24 * time.Hour, func(t time.Time) string { return t.Format("Mon") }}, // Weekdays
	{2 * time.Hour, func(t time.Time) string { return t.Format("3pm") }}, // Hours
	{2 * time.Minute, func(t time.Time) string { return t.Format("03:04pm") }}, // Minutes
	{2 * time.Second, func(t time.Time) string { return t.Format("03:04:05pm") }}, // Seconds
	}

	// suffix returns the correct suffix for a day number.
	//
	// For making human friendly dates:
	//
	// 1st, 2nd, 3rd, etc.
	//
	func suffix(day int) string {
	// The rules are pretty simple, everything ends in "th", except numbers that
	// end in 1, 2 or 3 which end in "st", "nd" and "rd" respectively. The only
	// exceptions are the teens (10 - 19) which always end in "th".
	if day >= 4 && day <= 20 {
	return "th"
	} else if day%10 == 1 {
	return "st"
	} else if day%10 == 2 {
	return "nd"
	} else if day%10 == 3 {
	return "rd"
	}
	return "th"
	}

	// opFromHours takes a number of hours and from that returns a function that
	// will produce good labels for tick marks in that time range. For example, if
	// the time range is small enough then the ticks will be marked with the
	// weekday, e.g. "Sun", if the time range is much larger the ticks may be
	// marked with the month, e.g. "Jul".
	func opFromHours(duration time.Duration) (TimeOp, error) {
	// Move down the list of choices from the largest granularity to the finest.
	// The first one that would generate more than MIN_TICKS for the given number
	// of hours is chosen and that TimeOp is returned.
	var Op TimeOp = nil
	for _, c := range choices {
	if duration > c.Duration {
	Op = c.Op
	break
	}
	}
	if Op == nil {
	return nil, fmt.Errorf("Couldn't calculate TimeOp")
	}
	return Op, nil
	}

	// Tick represents a single tick mark.
	type Tick struct {
	X float64
	Value string
	}

	// ToFlot converts a slice of Ticks into something that will serialize into
	// JSON that Flot consumes, which is an array of 2 element arrays. The 2 element
	// arrays contain an x offset and then a label as a string. For example:
	//
	// [ [ 0.5, "Saturday" ], [ 1.5, "Sunday" ] ]
	//
	func ToFlot(ticks []*Tick) []interface{} {
	ret := []interface{}{}
	for _, t := range ticks {
	ret = append(ret, []interface{}{t.X, t.Value})
	}
	return ret
	}

	// TickMarks produces human readable tickmarks to span the given timestamps.
	//
	// The array of timestamps are presumed to be in ascending order.
	// If 'in' is nil then the "Local" time zone is used.
	//
	// The choice of how to label the tick marks is based on the full time
	// range of the timestamps.
	func TickMarks(timestamps []int64, in time.Location) []Tick {
	loc := in
	if loc == nil {
	var err error
	loc, err = time.LoadLocation("Local")
	if err != nil {
	loc = time.UTC
	}
	}
	ret := []*Tick{}
	if len(timestamps) < 2 {
	sklog.Warningf("Insufficient number of commits: %d", len(timestamps))
	return ret
	}

	begin := time.Unix(timestamps[0], 0).In(loc)
	end := time.Unix(timestamps[len(timestamps)-1], 0).In(loc)
	duration := end.Sub(begin)
	op, err := opFromHours(duration)
	if err != nil {
	sklog.Errorf("Failed to calculate tickmarks for: %s %s: %s", begin, end, err)
	return ret
	}
	last := op(begin)
	ret = append(ret, &Tick{X: 0, Value: last})
	for i, t := range timestamps {
	if tickValue := op(time.Unix(t, 0).In(loc)); last != tickValue {
	last = tickValue
	ret = append(ret, &Tick{X: float64(i) - 0.5, Value: tickValue})
	}
	}

	return ret
	}

	// FlotTickMarks returns a struct that will serialize into JSON that Flot
	// expects for a value for tick marks.
	//
	// If an error occurs the tick list will be empty.
	//
	// tz is the timezone, and can be the empty string if the default (Eastern) timezone is acceptable.
	func FlotTickMarks(ts []int64, tz string) []interface{} {
	if tz == "" {
	tz = "America/New_York"
	}
	loc, err := time.LoadLocation(tz)
	if err != nil {
	loc, err = time.LoadLocation("UTC")
	if err != nil {
	sklog.Errorf("Failed to load the timezone %q: %s", tz, err)
	return []interface{}{}
	}
	}
	return ToFlot(TickMarks(ts, loc))
	}

	var durationRe = regexp.MustCompile("([0-9]+)([smhdw])$")

	// ParseDuration parses a human readable duration. Note that this understands
	// both days and weeks, which time.ParseDuration does not support.
	func ParseDuration(s string) (time.Duration, error) {
	parsed := durationRe.FindStringSubmatch(s)
	if len(parsed) != 3 {
	return time.Duration(0), fmt.Errorf("Invalid format: %s", s)
	}
	n, err := strconv.ParseInt(parsed[1], 10, 32)
	if err != nil {
	return time.Duration(0), fmt.Errorf("Invalid numeric format: %s", s)
	}
	d := time.Second
	switch parsed[2][0] {
	case 's':
	d = time.Duration(n) * time.Second
	case 'm':
	d = time.Duration(n) * time.Minute
	case 'h':
	d = time.Duration(n) * time.Hour
	case 'd':
	d = time.Duration(n) * 24 * time.Hour
	case 'w':
	d = time.Duration(n) * 7 * 24 * time.Hour
	}
	return d, nil
	}

	type delta struct {
	units string
	delta int64
	}

	var (
	deltas = []delta{
	{
	units: "y",
	delta: 365 * 24 * 60 * 60,
	},
	{
	units: "w",
	delta: 7 * 24 * 60 * 60,
	},
	{
	units: "d",
	delta: 24 * 60 * 60,
	},
	{
	units: "h",
	delta: 60 * 60,
	},
	{
	units: "m",
	delta: 60,
	},
	{
	units: "s",
	delta: 1,
	},
	}
	)

	// Duration returns a human friendly description of the given time.Duration.
	//
	// For example Duration(61*time.Second) returns " 1m 1s".
	//
	// The length of the string returned is guaranteed to always be 7.
	// A negative duration is treated the same as a positive duration.
	func Duration(duration time.Duration) string {
	ret := []string{}
	s := int64(math.Abs(duration.Seconds()))
	for _, d := range deltas {
	if d.delta <= s {
	ret = append(ret, fmt.Sprintf("%2d%s", s/d.delta, d.units))
	s = s % d.delta
	if len(ret) == 2 {
	break
	}
	}
	}
	if len(ret) == 0 {
	ret = append(ret, " ", " 0s")
	}
	if len(ret) < 2 {
	ret = []string{" ", ret[0]}
	}
	return strings.Join(ret, " ")
	}

	// JSONDuration is a type that implements the json.Unmarshal interface and can be used
	// to parse human readable durations from configuration files.
	type JSONDuration time.Duration

	func (d *JSONDuration) String() string {
	return strings.TrimSpace(Duration(time.Duration(*d)))
	}

	func (d *JSONDuration) UnmarshalJSON(durBytes []byte) error {
	durStr := strings.Trim(string(durBytes), "\"")
	duration, err := ParseDuration(string(durStr))
	if err != nil {
	return err
	}
	*d = JSONDuration(duration)
	return nil
	}