urfave-cli/context.go
2019-09-16 12:16:28 +05:30

282 lines
5.8 KiB
Go

package cli
import (
"context"
"errors"
"flag"
"fmt"
"os"
"os/signal"
"strings"
"syscall"
)
// Context is a type that is passed through to
// each Handler action in a cli application. Context
// can be used to retrieve context-specific args and
// parsed command-line options.
type Context struct {
context.Context
App *App
Command *Command
shellComplete bool
setFlags map[string]bool
flagSet *flag.FlagSet
parentContext *Context
}
// NewContext creates a new context. For use in when invoking an App or Command action.
func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context {
c := &Context{App: app, flagSet: set, parentContext: parentCtx}
if parentCtx != nil {
c.Context = parentCtx.Context
c.shellComplete = parentCtx.shellComplete
}
c.Command = &Command{}
if c.Context == nil {
ctx, cancel := context.WithCancel(context.Background())
go func() {
defer cancel()
sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
<-sigs
}()
c.Context = ctx
}
return c
}
// NumFlags returns the number of flags set
func (c *Context) NumFlags() int {
return c.flagSet.NFlag()
}
// Set sets a context flag to a value.
func (c *Context) Set(name, value string) error {
return c.flagSet.Set(name, value)
}
// IsSet determines if the flag was actually set
func (c *Context) IsSet(name string) bool {
if fs := lookupFlagSet(name, c); fs != nil {
if fs := lookupFlagSet(name, c); fs != nil {
isSet := false
fs.Visit(func(f *flag.Flag) {
if f.Name == name {
isSet = true
}
})
if isSet {
return true
}
}
f := lookupFlag(name, c)
if f == nil {
return false
}
return f.IsSet()
}
return false
}
// LocalFlagNames returns a slice of flag names used in this context.
func (c *Context) LocalFlagNames() []string {
var names []string
c.flagSet.Visit(makeFlagNameVisitor(&names))
return names
}
// FlagNames returns a slice of flag names used by the this context and all of
// its parent contexts.
func (c *Context) FlagNames() []string {
var names []string
for _, ctx := range c.Lineage() {
ctx.flagSet.Visit(makeFlagNameVisitor(&names))
}
return names
}
// Lineage returns *this* context and all of its ancestor contexts in order from
// child to parent
func (c *Context) Lineage() []*Context {
var lineage []*Context
for cur := c; cur != nil; cur = cur.parentContext {
lineage = append(lineage, cur)
}
return lineage
}
// value returns the value of the flag corresponding to `name`
func (c *Context) value(name string) interface{} {
return c.flagSet.Lookup(name).Value.(flag.Getter).Get()
}
// Args returns the command line arguments associated with the context.
func (c *Context) Args() Args {
ret := args(c.flagSet.Args())
return &ret
}
// NArg returns the number of the command line arguments.
func (c *Context) NArg() int {
return c.Args().Len()
}
func lookupFlag(name string, ctx *Context) Flag {
for _, c := range ctx.Lineage() {
if c.Command == nil {
continue
}
for _, f := range c.Command.Flags {
for _, n := range f.Names() {
if n == name {
return f
}
}
}
}
if ctx.App != nil {
for _, f := range ctx.App.Flags {
for _, n := range f.Names() {
if n == name {
return f
}
}
}
}
return nil
}
func lookupFlagSet(name string, ctx *Context) *flag.FlagSet {
for _, c := range ctx.Lineage() {
if f := c.flagSet.Lookup(name); f != nil {
return c.flagSet
}
}
return nil
}
func copyFlag(name string, ff *flag.Flag, set *flag.FlagSet) {
switch ff.Value.(type) {
case Serializer:
_ = set.Set(name, ff.Value.(Serializer).Serialize())
default:
_ = set.Set(name, ff.Value.String())
}
}
func normalizeFlags(flags []Flag, set *flag.FlagSet) error {
visited := make(map[string]bool)
set.Visit(func(f *flag.Flag) {
visited[f.Name] = true
})
for _, f := range flags {
parts := f.Names()
if len(parts) == 1 {
continue
}
var ff *flag.Flag
for _, name := range parts {
name = strings.Trim(name, " ")
if visited[name] {
if ff != nil {
return errors.New("Cannot use two forms of the same flag: " + name + " " + ff.Name)
}
ff = set.Lookup(name)
}
}
if ff == nil {
continue
}
for _, name := range parts {
name = strings.Trim(name, " ")
if !visited[name] {
copyFlag(name, ff, set)
}
}
}
return nil
}
func makeFlagNameVisitor(names *[]string) func(*flag.Flag) {
return func(f *flag.Flag) {
nameParts := strings.Split(f.Name, ",")
name := strings.TrimSpace(nameParts[0])
for _, part := range nameParts {
part = strings.TrimSpace(part)
if len(part) > len(name) {
name = part
}
}
if name != "" {
*names = append(*names, name)
}
}
}
type requiredFlagsErr interface {
error
getMissingFlags() []string
}
type errRequiredFlags struct {
missingFlags []string
}
func (e *errRequiredFlags) Error() string {
numberOfMissingFlags := len(e.missingFlags)
if numberOfMissingFlags == 1 {
return fmt.Sprintf("Required flag %q not set", e.missingFlags[0])
}
joinedMissingFlags := strings.Join(e.missingFlags, ", ")
return fmt.Sprintf("Required flags %q not set", joinedMissingFlags)
}
func (e *errRequiredFlags) getMissingFlags() []string {
return e.missingFlags
}
func checkRequiredFlags(flags []Flag, context *Context) requiredFlagsErr {
var missingFlags []string
for _, f := range flags {
if rf, ok := f.(RequiredFlag); ok && rf.IsRequired() {
var flagPresent bool
var flagName string
for _, key := range f.Names() {
if len(key) > 1 {
flagName = key
}
if context.IsSet(strings.TrimSpace(key)) {
flagPresent = true
}
}
if !flagPresent && flagName != "" {
missingFlags = append(missingFlags, flagName)
}
}
}
if len(missingFlags) != 0 {
return &errRequiredFlags{missingFlags: missingFlags}
}
return nil
}