Create an inverseBoolFlag

flag_bool_with_inverse.go

@@ -0,0 +1,181 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+)
+
+var (
+	DefaultInverseBoolPrefix = "no-"
+)
+
+type BoolWithInverseFlag struct {
+	// The BoolFlag which the positive and negative flags are generated from
+	*BoolFlag
+
+	// The prefix used to indicate a negative value
+	// Default: `env` becomes `no-env`
+	InversePrefix string
+
+	positiveFlag *BoolFlag
+	negativeFlag *BoolFlag
+
+	// pointers obtained from the embedded bool flag
+	posDest  *bool
+	posCount *int
+
+	negDest *bool
+}
+
+func (s *BoolWithInverseFlag) Flags() []Flag {
+	return []Flag{s.positiveFlag, s.negativeFlag}
+}
+
+func (s *BoolWithInverseFlag) IsSet() bool {
+	return (*s.posCount > 0) || (s.positiveFlag.IsSet() || s.negativeFlag.IsSet())
+}
+
+func (s *BoolWithInverseFlag) Value() bool {
+	return *s.posDest
+}
+
+func (s *BoolWithInverseFlag) RunAction(ctx *Context) error {
+	if *s.negDest && *s.posDest {
+		return fmt.Errorf("cannot set both flags `--%s` and `--%s`", s.positiveFlag.Name, s.negativeFlag.Name)
+	}
+
+	if *s.negDest {
+		err := ctx.Set(s.positiveFlag.Name, "false")
+		if err != nil {
+			return err
+		}
+	}
+
+	if s.BoolFlag.Action != nil {
+		return s.BoolFlag.Action(ctx, s.Value())
+	}
+
+	return nil
+}
+
+/*
+initialize creates a new BoolFlag that has an inverse flag
+
+consider a bool flag `--env`, there is no way to set it to false
+this function allows you to set `--env` or `--no-env` and in the command action
+it can be determined that BoolWithInverseFlag.IsSet()
+*/
+func (parent *BoolWithInverseFlag) initialize() {
+	child := parent.BoolFlag
+
+	parent.negDest = new(bool)
+	if child.Destination != nil {
+		parent.posDest = child.Destination
+	} else {
+		parent.posDest = new(bool)
+	}
+
+	if child.Config.Count != nil {
+		parent.posCount = child.Config.Count
+	} else {
+		parent.posCount = new(int)
+	}
+
+	parent.positiveFlag = child
+	parent.positiveFlag.Destination = parent.posDest
+	parent.positiveFlag.Config.Count = parent.posCount
+
+	parent.negativeFlag = &BoolFlag{
+		Category:    child.Category,
+		DefaultText: child.DefaultText,
+		FilePaths:   append([]string{}, child.FilePaths...),
+		Usage:       child.Usage,
+		Required:    child.Required,
+		Hidden:      child.Hidden,
+		Persistent:  child.Persistent,
+		Value:       child.Value,
+		Destination: parent.negDest,
+		TakesFile:   child.TakesFile,
+		OnlyOnce:    child.OnlyOnce,
+		hasBeenSet:  child.hasBeenSet,
+		applied:     child.applied,
+		creator:     boolValue{},
+		value:       child.value,
+	}
+
+	// Set inverse names ex: --env => --no-env
+	parent.negativeFlag.Name = parent.inverseName()
+	parent.negativeFlag.Aliases = parent.inverseAliases()
+
+	if len(child.EnvVars) > 0 {
+		parent.negativeFlag.EnvVars = make([]string, len(child.EnvVars))
+		for idx, envVar := range child.EnvVars {
+			parent.negativeFlag.EnvVars[idx] = strings.ToUpper(parent.InversePrefix) + envVar
+		}
+	}
+
+	return
+}
+
+func (parent *BoolWithInverseFlag) inverseName() string {
+	if parent.InversePrefix == "" {
+		parent.InversePrefix = DefaultInverseBoolPrefix
+	}
+
+	return parent.InversePrefix + parent.BoolFlag.Name
+}
+
+func (parent *BoolWithInverseFlag) inverseAliases() (aliases []string) {
+	if len(parent.BoolFlag.Aliases) > 0 {
+		aliases = make([]string, len(parent.BoolFlag.Aliases))
+		for idx, alias := range parent.BoolFlag.Aliases {
+			aliases[idx] = parent.InversePrefix + alias
+		}
+	}
+
+	return
+}
+
+func (s *BoolWithInverseFlag) Apply(set *flag.FlagSet) error {
+	if s.positiveFlag == nil {
+		s.initialize()
+	}
+
+	if err := s.positiveFlag.Apply(set); err != nil {
+		return err
+	}
+
+	if err := s.negativeFlag.Apply(set); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (s *BoolWithInverseFlag) Names() []string {
+	// Get Names when flag has not been initialized
+	if s.positiveFlag == nil {
+		return append(s.BoolFlag.Names(), FlagNames(s.inverseName(), s.inverseAliases())...)
+	}
+
+	if *s.negDest {
+		return s.negativeFlag.Names()
+	}
+
+	if *s.posDest {
+		return s.positiveFlag.Names()
+	}
+
+	return append(s.negativeFlag.Names(), s.positiveFlag.Names()...)
+}
+
+// Example for BoolFlag{Name: "env"}
+// --env     (default: false) || --no-env    (default: false)
+func (s *BoolWithInverseFlag) String() string {
+	if s.positiveFlag == nil {
+		return fmt.Sprintf("%s || --%s", s.BoolFlag.String(), s.inverseName())
+	}
+
+	return fmt.Sprintf("%s || %s", s.positiveFlag.String(), s.negativeFlag.String())
+}