cobra/cobra.go

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// Copyright © 2013 Steve Francia <spf@spf13.com>.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Commands similar to git, go tools and other modern CLI tools
// inspired by go, go-Commander, gh and subcommand
package cobra
import (
"fmt"
"io"
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"reflect"
"strconv"
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"strings"
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"text/template"
"unicode"
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)
var templateFuncs template.FuncMap = template.FuncMap{
"trim": strings.TrimSpace,
"trimRightSpace": trimRightSpace,
"rpad": rpad,
"gt": Gt,
"eq": Eq,
}
var initializers []func()
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// automatic prefix matching can be a dangerous thing to automatically enable in CLI tools.
// Set this to true to enable it
var EnablePrefixMatching bool = false
// enables an information splash screen on Windows if the CLI is started from explorer.exe.
var EnableWindowsMouseTrap bool = true
var MousetrapHelpText string = `This is a command line tool
You need to open cmd.exe and run it from there.
`
//AddTemplateFunc adds a template function that's available to Usage and Help
//template generation.
func AddTemplateFunc(name string, tmplFunc interface{}) {
templateFuncs[name] = tmplFunc
}
//AddTemplateFuncs adds multiple template functions availalble to Usage and
//Help template generation.
func AddTemplateFuncs(tmplFuncs template.FuncMap) {
for k, v := range tmplFuncs {
templateFuncs[k] = v
}
}
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//OnInitialize takes a series of func() arguments and appends them to a slice of func().
func OnInitialize(y ...func()) {
for _, x := range y {
initializers = append(initializers, x)
}
}
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//Gt takes two types and checks whether the first type is greater than the second. In case of types Arrays, Chans,
//Maps and Slices, Gt will compare their lengths. Ints are compared directly while strings are first parsed as
//ints and then compared.
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func Gt(a interface{}, b interface{}) bool {
var left, right int64
av := reflect.ValueOf(a)
switch av.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
left = int64(av.Len())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
left = av.Int()
case reflect.String:
left, _ = strconv.ParseInt(av.String(), 10, 64)
}
bv := reflect.ValueOf(b)
switch bv.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
right = int64(bv.Len())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
right = bv.Int()
case reflect.String:
right, _ = strconv.ParseInt(bv.String(), 10, 64)
}
return left > right
}
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//Eq takes two types and checks whether they are equal. Supported types are int and string. Unsupported types will panic.
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func Eq(a interface{}, b interface{}) bool {
av := reflect.ValueOf(a)
bv := reflect.ValueOf(b)
switch av.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
panic("Eq called on unsupported type")
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return av.Int() == bv.Int()
case reflect.String:
return av.String() == bv.String()
}
return false
}
func trimRightSpace(s string) string {
return strings.TrimRightFunc(s, unicode.IsSpace)
}
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//rpad adds padding to the right of a string
func rpad(s string, padding int) string {
template := fmt.Sprintf("%%-%ds", padding)
return fmt.Sprintf(template, s)
}
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// tmpl executes the given template text on data, writing the result to w.
func tmpl(w io.Writer, text string, data interface{}) error {
t := template.New("top")
t.Funcs(templateFuncs)
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template.Must(t.Parse(text))
return t.Execute(w, data)
}