1package cli
2
3import (
4	"errors"
5	"flag"
6	"reflect"
7	"strings"
8	"syscall"
9)
10
11// Context is a type that is passed through to
12// each Handler action in a cli application. Context
13// can be used to retrieve context-specific Args and
14// parsed command-line options.
15type Context struct {
16	App           *App
17	Command       Command
18	shellComplete bool
19	flagSet       *flag.FlagSet
20	setFlags      map[string]bool
21	parentContext *Context
22}
23
24// NewContext creates a new context. For use in when invoking an App or Command action.
25func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context {
26	c := &Context{App: app, flagSet: set, parentContext: parentCtx}
27
28	if parentCtx != nil {
29		c.shellComplete = parentCtx.shellComplete
30	}
31
32	return c
33}
34
35// NumFlags returns the number of flags set
36func (c *Context) NumFlags() int {
37	return c.flagSet.NFlag()
38}
39
40// Set sets a context flag to a value.
41func (c *Context) Set(name, value string) error {
42	c.setFlags = nil
43	return c.flagSet.Set(name, value)
44}
45
46// GlobalSet sets a context flag to a value on the global flagset
47func (c *Context) GlobalSet(name, value string) error {
48	globalContext(c).setFlags = nil
49	return globalContext(c).flagSet.Set(name, value)
50}
51
52// IsSet determines if the flag was actually set
53func (c *Context) IsSet(name string) bool {
54	if c.setFlags == nil {
55		c.setFlags = make(map[string]bool)
56
57		c.flagSet.Visit(func(f *flag.Flag) {
58			c.setFlags[f.Name] = true
59		})
60
61		c.flagSet.VisitAll(func(f *flag.Flag) {
62			if _, ok := c.setFlags[f.Name]; ok {
63				return
64			}
65			c.setFlags[f.Name] = false
66		})
67
68		// XXX hack to support IsSet for flags with EnvVar
69		//
70		// There isn't an easy way to do this with the current implementation since
71		// whether a flag was set via an environment variable is very difficult to
72		// determine here. Instead, we intend to introduce a backwards incompatible
73		// change in version 2 to add `IsSet` to the Flag interface to push the
74		// responsibility closer to where the information required to determine
75		// whether a flag is set by non-standard means such as environment
76		// variables is avaliable.
77		//
78		// See https://github.com/urfave/cli/issues/294 for additional discussion
79		flags := c.Command.Flags
80		if c.Command.Name == "" { // cannot == Command{} since it contains slice types
81			if c.App != nil {
82				flags = c.App.Flags
83			}
84		}
85		for _, f := range flags {
86			eachName(f.GetName(), func(name string) {
87				if isSet, ok := c.setFlags[name]; isSet || !ok {
88					return
89				}
90
91				val := reflect.ValueOf(f)
92				if val.Kind() == reflect.Ptr {
93					val = val.Elem()
94				}
95
96				envVarValue := val.FieldByName("EnvVar")
97				if !envVarValue.IsValid() {
98					return
99				}
100
101				eachName(envVarValue.String(), func(envVar string) {
102					envVar = strings.TrimSpace(envVar)
103					if _, ok := syscall.Getenv(envVar); ok {
104						c.setFlags[name] = true
105						return
106					}
107				})
108			})
109		}
110	}
111
112	return c.setFlags[name]
113}
114
115// GlobalIsSet determines if the global flag was actually set
116func (c *Context) GlobalIsSet(name string) bool {
117	ctx := c
118	if ctx.parentContext != nil {
119		ctx = ctx.parentContext
120	}
121
122	for ; ctx != nil; ctx = ctx.parentContext {
123		if ctx.IsSet(name) {
124			return true
125		}
126	}
127	return false
128}
129
130// FlagNames returns a slice of flag names used in this context.
131func (c *Context) FlagNames() (names []string) {
132	for _, flag := range c.Command.Flags {
133		name := strings.Split(flag.GetName(), ",")[0]
134		if name == "help" {
135			continue
136		}
137		names = append(names, name)
138	}
139	return
140}
141
142// GlobalFlagNames returns a slice of global flag names used by the app.
143func (c *Context) GlobalFlagNames() (names []string) {
144	for _, flag := range c.App.Flags {
145		name := strings.Split(flag.GetName(), ",")[0]
146		if name == "help" || name == "version" {
147			continue
148		}
149		names = append(names, name)
150	}
151	return
152}
153
154// Parent returns the parent context, if any
155func (c *Context) Parent() *Context {
156	return c.parentContext
157}
158
159// value returns the value of the flag coressponding to `name`
160func (c *Context) value(name string) interface{} {
161	return c.flagSet.Lookup(name).Value.(flag.Getter).Get()
162}
163
164// Args contains apps console arguments
165type Args []string
166
167// Args returns the command line arguments associated with the context.
168func (c *Context) Args() Args {
169	args := Args(c.flagSet.Args())
170	return args
171}
172
173// NArg returns the number of the command line arguments.
174func (c *Context) NArg() int {
175	return len(c.Args())
176}
177
178// Get returns the nth argument, or else a blank string
179func (a Args) Get(n int) string {
180	if len(a) > n {
181		return a[n]
182	}
183	return ""
184}
185
186// First returns the first argument, or else a blank string
187func (a Args) First() string {
188	return a.Get(0)
189}
190
191// Tail returns the rest of the arguments (not the first one)
192// or else an empty string slice
193func (a Args) Tail() []string {
194	if len(a) >= 2 {
195		return []string(a)[1:]
196	}
197	return []string{}
198}
199
200// Present checks if there are any arguments present
201func (a Args) Present() bool {
202	return len(a) != 0
203}
204
205// Swap swaps arguments at the given indexes
206func (a Args) Swap(from, to int) error {
207	if from >= len(a) || to >= len(a) {
208		return errors.New("index out of range")
209	}
210	a[from], a[to] = a[to], a[from]
211	return nil
212}
213
214func globalContext(ctx *Context) *Context {
215	if ctx == nil {
216		return nil
217	}
218
219	for {
220		if ctx.parentContext == nil {
221			return ctx
222		}
223		ctx = ctx.parentContext
224	}
225}
226
227func lookupGlobalFlagSet(name string, ctx *Context) *flag.FlagSet {
228	if ctx.parentContext != nil {
229		ctx = ctx.parentContext
230	}
231	for ; ctx != nil; ctx = ctx.parentContext {
232		if f := ctx.flagSet.Lookup(name); f != nil {
233			return ctx.flagSet
234		}
235	}
236	return nil
237}
238
239func copyFlag(name string, ff *flag.Flag, set *flag.FlagSet) {
240	switch ff.Value.(type) {
241	case *StringSlice:
242	default:
243		set.Set(name, ff.Value.String())
244	}
245}
246
247func normalizeFlags(flags []Flag, set *flag.FlagSet) error {
248	visited := make(map[string]bool)
249	set.Visit(func(f *flag.Flag) {
250		visited[f.Name] = true
251	})
252	for _, f := range flags {
253		parts := strings.Split(f.GetName(), ",")
254		if len(parts) == 1 {
255			continue
256		}
257		var ff *flag.Flag
258		for _, name := range parts {
259			name = strings.Trim(name, " ")
260			if visited[name] {
261				if ff != nil {
262					return errors.New("Cannot use two forms of the same flag: " + name + " " + ff.Name)
263				}
264				ff = set.Lookup(name)
265			}
266		}
267		if ff == nil {
268			continue
269		}
270		for _, name := range parts {
271			name = strings.Trim(name, " ")
272			if !visited[name] {
273				copyFlag(name, ff, set)
274			}
275		}
276	}
277	return nil
278}
279