path: root/vendor/gopkg.in/urfave/cli.v1/context.go

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
}