mirror of
https://gitee.com/rainbond/Rainbond.git
synced 2024-12-05 13:17:42 +08:00
381 lines
9.4 KiB
Go
381 lines
9.4 KiB
Go
package cron
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import (
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"fmt"
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"math"
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"strconv"
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"strings"
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"time"
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)
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// Configuration options for creating a parser. Most options specify which
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// fields should be included, while others enable features. If a field is not
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// included the parser will assume a default value. These options do not change
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// the order fields are parse in.
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type ParseOption int
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const (
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Second ParseOption = 1 << iota // Seconds field, default 0
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Minute // Minutes field, default 0
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Hour // Hours field, default 0
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Dom // Day of month field, default *
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Month // Month field, default *
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Dow // Day of week field, default *
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DowOptional // Optional day of week field, default *
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Descriptor // Allow descriptors such as @monthly, @weekly, etc.
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)
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var places = []ParseOption{
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Second,
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Minute,
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Hour,
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Dom,
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Month,
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Dow,
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}
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var defaults = []string{
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"0",
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"0",
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"0",
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"*",
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"*",
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"*",
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}
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// A custom Parser that can be configured.
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type Parser struct {
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options ParseOption
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optionals int
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}
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// Creates a custom Parser with custom options.
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//
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// // Standard parser without descriptors
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// specParser := NewParser(Minute | Hour | Dom | Month | Dow)
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// sched, err := specParser.Parse("0 0 15 */3 *")
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//
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// // Same as above, just excludes time fields
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// subsParser := NewParser(Dom | Month | Dow)
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// sched, err := specParser.Parse("15 */3 *")
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//
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// // Same as above, just makes Dow optional
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// subsParser := NewParser(Dom | Month | DowOptional)
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// sched, err := specParser.Parse("15 */3")
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//
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func NewParser(options ParseOption) Parser {
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optionals := 0
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if options&DowOptional > 0 {
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options |= Dow
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optionals++
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}
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return Parser{options, optionals}
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}
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// Parse returns a new crontab schedule representing the given spec.
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// It returns a descriptive error if the spec is not valid.
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// It accepts crontab specs and features configured by NewParser.
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func (p Parser) Parse(spec string) (Schedule, error) {
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if len(spec) == 0 {
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return nil, fmt.Errorf("Empty spec string")
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}
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if spec[0] == '@' && p.options&Descriptor > 0 {
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return parseDescriptor(spec)
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}
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// Figure out how many fields we need
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max := 0
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for _, place := range places {
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if p.options&place > 0 {
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max++
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}
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}
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min := max - p.optionals
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// Split fields on whitespace
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fields := strings.Fields(spec)
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// Validate number of fields
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if count := len(fields); count < min || count > max {
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if min == max {
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return nil, fmt.Errorf("Expected exactly %d fields, found %d: %s", min, count, spec)
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}
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return nil, fmt.Errorf("Expected %d to %d fields, found %d: %s", min, max, count, spec)
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}
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// Fill in missing fields
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fields = expandFields(fields, p.options)
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var err error
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field := func(field string, r bounds) uint64 {
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if err != nil {
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return 0
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}
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var bits uint64
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bits, err = getField(field, r)
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return bits
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}
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var (
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second = field(fields[0], seconds)
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minute = field(fields[1], minutes)
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hour = field(fields[2], hours)
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dayofmonth = field(fields[3], dom)
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month = field(fields[4], months)
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dayofweek = field(fields[5], dow)
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)
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if err != nil {
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return nil, err
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}
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return &SpecSchedule{
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Second: second,
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Minute: minute,
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Hour: hour,
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Dom: dayofmonth,
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Month: month,
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Dow: dayofweek,
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}, nil
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}
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func expandFields(fields []string, options ParseOption) []string {
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n := 0
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count := len(fields)
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expFields := make([]string, len(places))
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copy(expFields, defaults)
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for i, place := range places {
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if options&place > 0 {
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expFields[i] = fields[n]
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n++
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}
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if n == count {
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break
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}
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}
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return expFields
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}
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var standardParser = NewParser(
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Minute | Hour | Dom | Month | Dow | Descriptor,
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)
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// ParseStandard returns a new crontab schedule representing the given standardSpec
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// (https://en.wikipedia.org/wiki/Cron). It differs from Parse requiring to always
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// pass 5 entries representing: minute, hour, day of month, month and day of week,
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// in that order. It returns a descriptive error if the spec is not valid.
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//
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// It accepts
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// - Standard crontab specs, e.g. "* * * * ?"
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// - Descriptors, e.g. "@midnight", "@every 1h30m"
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func ParseStandard(standardSpec string) (Schedule, error) {
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return standardParser.Parse(standardSpec)
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}
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var defaultParser = NewParser(
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Second | Minute | Hour | Dom | Month | DowOptional | Descriptor,
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)
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// Parse returns a new crontab schedule representing the given spec.
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// It returns a descriptive error if the spec is not valid.
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//
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// It accepts
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// - Full crontab specs, e.g. "* * * * * ?"
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// - Descriptors, e.g. "@midnight", "@every 1h30m"
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func Parse(spec string) (Schedule, error) {
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return defaultParser.Parse(spec)
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}
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// getField returns an Int with the bits set representing all of the times that
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// the field represents or error parsing field value. A "field" is a comma-separated
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// list of "ranges".
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func getField(field string, r bounds) (uint64, error) {
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var bits uint64
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ranges := strings.FieldsFunc(field, func(r rune) bool { return r == ',' })
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for _, expr := range ranges {
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bit, err := getRange(expr, r)
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if err != nil {
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return bits, err
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}
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bits |= bit
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}
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return bits, nil
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}
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// getRange returns the bits indicated by the given expression:
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// number | number "-" number [ "/" number ]
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// or error parsing range.
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func getRange(expr string, r bounds) (uint64, error) {
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var (
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start, end, step uint
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rangeAndStep = strings.Split(expr, "/")
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lowAndHigh = strings.Split(rangeAndStep[0], "-")
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singleDigit = len(lowAndHigh) == 1
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err error
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)
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var extra uint64
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if lowAndHigh[0] == "*" || lowAndHigh[0] == "?" {
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start = r.min
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end = r.max
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extra = starBit
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} else {
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start, err = parseIntOrName(lowAndHigh[0], r.names)
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if err != nil {
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return 0, err
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}
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switch len(lowAndHigh) {
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case 1:
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end = start
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case 2:
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end, err = parseIntOrName(lowAndHigh[1], r.names)
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if err != nil {
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return 0, err
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}
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default:
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return 0, fmt.Errorf("Too many hyphens: %s", expr)
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}
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}
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switch len(rangeAndStep) {
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case 1:
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step = 1
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case 2:
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step, err = mustParseInt(rangeAndStep[1])
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if err != nil {
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return 0, err
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}
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// Special handling: "N/step" means "N-max/step".
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if singleDigit {
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end = r.max
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}
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default:
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return 0, fmt.Errorf("Too many slashes: %s", expr)
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}
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if start < r.min {
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return 0, fmt.Errorf("Beginning of range (%d) below minimum (%d): %s", start, r.min, expr)
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}
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if end > r.max {
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return 0, fmt.Errorf("End of range (%d) above maximum (%d): %s", end, r.max, expr)
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}
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if start > end {
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return 0, fmt.Errorf("Beginning of range (%d) beyond end of range (%d): %s", start, end, expr)
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}
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if step == 0 {
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return 0, fmt.Errorf("Step of range should be a positive number: %s", expr)
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}
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return getBits(start, end, step) | extra, nil
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}
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// parseIntOrName returns the (possibly-named) integer contained in expr.
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func parseIntOrName(expr string, names map[string]uint) (uint, error) {
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if names != nil {
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if namedInt, ok := names[strings.ToLower(expr)]; ok {
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return namedInt, nil
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}
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}
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return mustParseInt(expr)
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}
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// mustParseInt parses the given expression as an int or returns an error.
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func mustParseInt(expr string) (uint, error) {
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num, err := strconv.Atoi(expr)
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if err != nil {
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return 0, fmt.Errorf("Failed to parse int from %s: %s", expr, err)
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}
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if num < 0 {
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return 0, fmt.Errorf("Negative number (%d) not allowed: %s", num, expr)
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}
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return uint(num), nil
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}
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// getBits sets all bits in the range [min, max], modulo the given step size.
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func getBits(min, max, step uint) uint64 {
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var bits uint64
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// If step is 1, use shifts.
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if step == 1 {
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return ^(math.MaxUint64 << (max + 1)) & (math.MaxUint64 << min)
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}
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// Else, use a simple loop.
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for i := min; i <= max; i += step {
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bits |= 1 << i
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}
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return bits
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}
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// all returns all bits within the given bounds. (plus the star bit)
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func all(r bounds) uint64 {
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return getBits(r.min, r.max, 1) | starBit
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}
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// parseDescriptor returns a predefined schedule for the expression, or error if none matches.
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func parseDescriptor(descriptor string) (Schedule, error) {
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switch descriptor {
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case "@yearly", "@annually":
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return &SpecSchedule{
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Second: 1 << seconds.min,
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Minute: 1 << minutes.min,
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Hour: 1 << hours.min,
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Dom: 1 << dom.min,
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Month: 1 << months.min,
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Dow: all(dow),
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}, nil
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case "@monthly":
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return &SpecSchedule{
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Second: 1 << seconds.min,
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Minute: 1 << minutes.min,
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Hour: 1 << hours.min,
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Dom: 1 << dom.min,
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Month: all(months),
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Dow: all(dow),
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}, nil
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case "@weekly":
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return &SpecSchedule{
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Second: 1 << seconds.min,
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Minute: 1 << minutes.min,
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Hour: 1 << hours.min,
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Dom: all(dom),
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Month: all(months),
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Dow: 1 << dow.min,
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}, nil
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case "@daily", "@midnight":
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return &SpecSchedule{
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Second: 1 << seconds.min,
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Minute: 1 << minutes.min,
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Hour: 1 << hours.min,
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Dom: all(dom),
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Month: all(months),
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Dow: all(dow),
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}, nil
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case "@hourly":
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return &SpecSchedule{
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Second: 1 << seconds.min,
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Minute: 1 << minutes.min,
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Hour: all(hours),
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Dom: all(dom),
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Month: all(months),
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Dow: all(dow),
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}, nil
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}
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const every = "@every "
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if strings.HasPrefix(descriptor, every) {
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duration, err := time.ParseDuration(descriptor[len(every):])
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if err != nil {
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return nil, fmt.Errorf("Failed to parse duration %s: %s", descriptor, err)
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}
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return Every(duration), nil
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}
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return nil, fmt.Errorf("Unrecognized descriptor: %s", descriptor)
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}
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