package cli
import (
"errors"
"flag"
"reflect"
"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 {
App *App
Command Command
shellComplete bool
flagSet *flag.FlagSet
setFlags map[string]bool
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.shellComplete = parentCtx.shellComplete
}
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 {
c.setFlags = nil
return c.flagSet.Set(name, value)
}
// GlobalSet sets a context flag to a value on the global flagset
func (c *Context) GlobalSet(name, value string) error {
globalContext(c).setFlags = nil
return globalContext(c).flagSet.Set(name, value)
}
// IsSet determines if the flag was actually set
func (c *Context) IsSet(name string) bool {
if c.setFlags == nil {
c.setFlags = make(map[string]bool)
c.flagSet.Visit(func(f *flag.Flag) {
c.setFlags[f.Name] = true
})
c.flagSet.VisitAll(func(f *flag.Flag) {
if _, ok := c.setFlags[f.Name]; ok {
return
}
c.setFlags[f.Name] = false
})
// XXX hack to support IsSet for flags with EnvVar
//
// There isn't an easy way to do this with the current implementation since
// whether a flag was set via an environment variable is very difficult to
// determine here. Instead, we intend to introduce a backwards incompatible
// change in version 2 to add `IsSet` to the Flag interface to push the
// responsibility closer to where the information required to determine
// whether a flag is set by non-standard means such as environment
// variables is avaliable.
//
// See https://github.com/urfave/cli/issues/294 for additional discussion
flags := c.Command.Flags
if c.Command.Name == "" { // cannot == Command{} since it contains slice types
if c.App != nil {
flags = c.App.Flags
}
}
for _, f := range flags {
eachName(f.GetName(), func(name string) {
if isSet, ok := c.setFlags[name]; isSet || !ok {
return
}
val := reflect.ValueOf(f)
if val.Kind() == reflect.Ptr {
val = val.Elem()
}
envVarValue := val.FieldByName("EnvVar")
if !envVarValue.IsValid() {
return
}
eachName(envVarValue.String(), func(envVar string) {
envVar = strings.TrimSpace(envVar)
if _, ok := syscall.Getenv(envVar); ok {
c.setFlags[name] = true
return
}
})
})
}
}
return c.setFlags[name]
}
// GlobalIsSet determines if the global flag was actually set
func (c *Context) GlobalIsSet(name string) bool {
ctx := c
if ctx.parentContext != nil {
ctx = ctx.parentContext
}
for ; ctx != nil; ctx = ctx.parentContext {
if ctx.IsSet(name) {
return true
}
}
return false
}
// FlagNames returns a slice of flag names used in this context.
func (c *Context) FlagNames() (names []string) {
for _, flag := range c.Command.Flags {
name := strings.Split(flag.GetName(), ",")[0]
if name == "help" {
continue
}
names = append(names, name)
}
return
}
// GlobalFlagNames returns a slice of global flag names used by the app.
func (c *Context) GlobalFlagNames() (names []string) {
for _, flag := range c.App.Flags {
name := strings.Split(flag.GetName(), ",")[0]
if name == "help" || name == "version" {
continue
}
names = append(names, name)
}
return
}
// Parent returns the parent context, if any
func (c *Context) Parent() *Context {
return c.parentContext
}
// value returns the value of the flag coressponding to `name`
func (c *Context) value(name string) interface{} {
return c.flagSet.Lookup(name).Value.(flag.Getter).Get()
}
// Args contains apps console arguments
type Args []string
// Args returns the command line arguments associated with the context.
func (c *Context) Args() Args {
args := Args(c.flagSet.Args())
return args
}
// NArg returns the number of the command line arguments.
func (c *Context) NArg() int {
return len(c.Args())
}
// Get returns the nth argument, or else a blank string
func (a Args) Get(n int) string {
if len(a) > n {
return a[n]
}
return ""
}
// First returns the first argument, or else a blank string
func (a Args) First() string {
return a.Get(0)
}
// Tail returns the rest of the arguments (not the first one)
// or else an empty string slice
func (a Args) Tail() []string {
if len(a) >= 2 {
return []string(a)[1:]
}
return []string{}
}
// Present checks if there are any arguments present
func (a Args) Present() bool {
return len(a) != 0
}
// Swap swaps arguments at the given indexes
func (a Args) Swap(from, to int) error {
if from >= len(a) || to >= len(a) {
return errors.New("index out of range")
}
a[from], a[to] = a[to], a[from]
return nil
}
func globalContext(ctx *Context) *Context {
if ctx == nil {
return nil
}
for {
if ctx.parentContext == nil {
return ctx
}
ctx = ctx.parentContext
}
}
func lookupGlobalFlagSet(name string, ctx *Context) *flag.FlagSet {
if ctx.parentContext != nil {
ctx = ctx.parentContext
}
for ; ctx != nil; ctx = ctx.parentContext {
if f := ctx.flagSet.Lookup(name); f != nil {
return ctx.flagSet
}
}
return nil
}
func copyFlag(name string, ff *flag.Flag, set *flag.FlagSet) {
switch ff.Value.(type) {
case *StringSlice:
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 := strings.Split(f.GetName(), ",")
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
}
