|
6 | 6 | package cmdflag |
7 | 7 |
|
8 | 8 | import ( |
| 9 | + "errors" |
9 | 10 | "flag" |
10 | 11 | "fmt" |
11 | | - "os" |
12 | | - "strconv" |
13 | 12 | "strings" |
14 | | - |
15 | | - "cmd/go/internal/base" |
16 | 13 | ) |
17 | 14 |
|
18 | 15 | // The flag handling part of go commands such as test is large and distracting. |
19 | 16 | // We can't use the standard flag package because some of the flags from |
20 | 17 | // our command line are for us, and some are for the binary we're running, |
21 | 18 | // and some are for both. |
22 | 19 |
|
23 | | -// Defn defines a flag we know about. |
24 | | -type Defn struct { |
25 | | - Name string // Name on command line. |
26 | | - BoolVar *bool // If it's a boolean flag, this points to it. |
27 | | - Value flag.Value // The flag.Value represented. |
28 | | - PassToTest bool // Pass to the test binary? Used only by go test. |
29 | | - Present bool // Flag has been seen. |
30 | | -} |
| 20 | +// ErrFlagTerminator indicates the distinguished token "--", which causes the |
| 21 | +// flag package to treat all subsequent arguments as non-flags. |
| 22 | +var ErrFlagTerminator = errors.New("flag terminator") |
31 | 23 |
|
32 | | -// IsBool reports whether v is a bool flag. |
33 | | -func IsBool(v flag.Value) bool { |
34 | | - vv, ok := v.(interface { |
35 | | - IsBoolFlag() bool |
36 | | - }) |
37 | | - if ok { |
38 | | - return vv.IsBoolFlag() |
39 | | - } |
40 | | - return false |
| 24 | +// A FlagNotDefinedError indicates a flag-like argument that does not correspond |
| 25 | +// to any registered flag in a FlagSet. |
| 26 | +type FlagNotDefinedError struct { |
| 27 | + RawArg string // the original argument, like --foo or -foo=value |
| 28 | + Name string |
| 29 | + HasValue bool // is this the -foo=value or --foo=value form? |
| 30 | + Value string // only provided if HasValue is true |
41 | 31 | } |
42 | 32 |
|
43 | | -// SetBool sets the addressed boolean to the value. |
44 | | -func SetBool(cmd string, flag *bool, value string) { |
45 | | - x, err := strconv.ParseBool(value) |
46 | | - if err != nil { |
47 | | - SyntaxError(cmd, "illegal bool flag value "+value) |
48 | | - } |
49 | | - *flag = x |
| 33 | +func (e FlagNotDefinedError) Error() string { |
| 34 | + return fmt.Sprintf("flag provided but not defined: -%s", e.Name) |
50 | 35 | } |
51 | 36 |
|
52 | | -// SetInt sets the addressed integer to the value. |
53 | | -func SetInt(cmd string, flag *int, value string) { |
54 | | - x, err := strconv.Atoi(value) |
55 | | - if err != nil { |
56 | | - SyntaxError(cmd, "illegal int flag value "+value) |
57 | | - } |
58 | | - *flag = x |
| 37 | +// A NonFlagError indicates an argument that is not a syntactically-valid flag. |
| 38 | +type NonFlagError struct { |
| 39 | + RawArg string |
59 | 40 | } |
60 | 41 |
|
61 | | -// SyntaxError reports an argument syntax error and exits the program. |
62 | | -func SyntaxError(cmd, msg string) { |
63 | | - fmt.Fprintf(os.Stderr, "go %s: %s\n", cmd, msg) |
64 | | - if cmd == "test" { |
65 | | - fmt.Fprintf(os.Stderr, `run "go help %s" or "go help testflag" for more information`+"\n", cmd) |
66 | | - } else { |
67 | | - fmt.Fprintf(os.Stderr, `run "go help %s" for more information`+"\n", cmd) |
68 | | - } |
69 | | - base.SetExitStatus(2) |
70 | | - base.Exit() |
| 42 | +func (e NonFlagError) Error() string { |
| 43 | + return fmt.Sprintf("not a flag: %q", e.RawArg) |
71 | 44 | } |
72 | 45 |
|
73 | | -// AddKnownFlags registers the flags in defns with base.AddKnownFlag. |
74 | | -func AddKnownFlags(cmd string, defns []*Defn) { |
75 | | - for _, f := range defns { |
76 | | - base.AddKnownFlag(f.Name) |
77 | | - base.AddKnownFlag(cmd + "." + f.Name) |
78 | | - } |
79 | | -} |
| 46 | +// ParseOne sees if args[0] is present in the given flag set and if so, |
| 47 | +// sets its value and returns the flag along with the remaining (unused) arguments. |
| 48 | +// |
| 49 | +// ParseOne always returns either a non-nil Flag or a non-nil error, |
| 50 | +// and always consumes at least one argument (even on error). |
| 51 | +// |
| 52 | +// Unlike (*flag.FlagSet).Parse, ParseOne does not log its own errors. |
| 53 | +func ParseOne(fs *flag.FlagSet, args []string) (f *flag.Flag, remainingArgs []string, err error) { |
| 54 | + // This function is loosely derived from (*flag.FlagSet).parseOne. |
80 | 55 |
|
81 | | -// Parse sees if argument i is present in the definitions and if so, |
82 | | -// returns its definition, value, and whether it consumed an extra word. |
83 | | -// If the flag begins (cmd.Name()+".") it is ignored for the purpose of this function. |
84 | | -func Parse(cmd string, usage func(), defns []*Defn, args []string, i int) (f *Defn, value string, extra bool) { |
85 | | - arg := args[i] |
86 | | - if strings.HasPrefix(arg, "--") { // reduce two minuses to one |
87 | | - arg = arg[1:] |
| 56 | + raw, args := args[0], args[1:] |
| 57 | + arg := raw |
| 58 | + if strings.HasPrefix(arg, "--") { |
| 59 | + if arg == "--" { |
| 60 | + return nil, args, ErrFlagTerminator |
| 61 | + } |
| 62 | + arg = arg[1:] // reduce two minuses to one |
88 | 63 | } |
| 64 | + |
89 | 65 | switch arg { |
90 | 66 | case "-?", "-h", "-help": |
91 | | - usage() |
| 67 | + return nil, args, flag.ErrHelp |
92 | 68 | } |
93 | | - if arg == "" || arg[0] != '-' { |
94 | | - return |
| 69 | + if len(arg) < 2 || arg[0] != '-' || arg[1] == '-' || arg[1] == '=' { |
| 70 | + return nil, args, NonFlagError{RawArg: raw} |
95 | 71 | } |
| 72 | + |
96 | 73 | name := arg[1:] |
97 | | - // If there's already a prefix such as "test.", drop it for now. |
98 | | - name = strings.TrimPrefix(name, cmd+".") |
99 | | - equals := strings.Index(name, "=") |
100 | | - if equals >= 0 { |
101 | | - value = name[equals+1:] |
102 | | - name = name[:equals] |
| 74 | + hasValue := false |
| 75 | + value := "" |
| 76 | + if i := strings.Index(name, "="); i >= 0 { |
| 77 | + value = name[i+1:] |
| 78 | + hasValue = true |
| 79 | + name = name[0:i] |
103 | 80 | } |
104 | | - for _, f = range defns { |
105 | | - if name == f.Name { |
106 | | - // Booleans are special because they have modes -x, -x=true, -x=false. |
107 | | - if f.BoolVar != nil || IsBool(f.Value) { |
108 | | - if equals < 0 { // Otherwise, it's been set and will be verified in SetBool. |
109 | | - value = "true" |
110 | | - } else { |
111 | | - // verify it parses |
112 | | - SetBool(cmd, new(bool), value) |
113 | | - } |
114 | | - } else { // Non-booleans must have a value. |
115 | | - extra = equals < 0 |
116 | | - if extra { |
117 | | - if i+1 >= len(args) { |
118 | | - SyntaxError(cmd, "missing argument for flag "+f.Name) |
119 | | - } |
120 | | - value = args[i+1] |
121 | | - } |
122 | | - } |
123 | | - if f.Present { |
124 | | - SyntaxError(cmd, f.Name+" flag may be set only once") |
125 | | - } |
126 | | - f.Present = true |
127 | | - return |
| 81 | + |
| 82 | + f = fs.Lookup(name) |
| 83 | + if f == nil { |
| 84 | + return nil, args, FlagNotDefinedError{ |
| 85 | + RawArg: raw, |
| 86 | + Name: name, |
| 87 | + HasValue: hasValue, |
| 88 | + Value: value, |
128 | 89 | } |
129 | 90 | } |
130 | | - f = nil |
131 | | - return |
132 | | -} |
133 | 91 |
|
134 | | -// FindGOFLAGS extracts and returns the flags matching defns from GOFLAGS. |
135 | | -// Ideally the caller would mention that the flags were from GOFLAGS |
136 | | -// when reporting errors, but that's too hard for now. |
137 | | -func FindGOFLAGS(defns []*Defn) []string { |
138 | | - var flags []string |
139 | | - for _, flag := range base.GOFLAGS() { |
140 | | - // Flags returned by base.GOFLAGS are well-formed, one of: |
141 | | - // -x |
142 | | - // --x |
143 | | - // -x=value |
144 | | - // --x=value |
145 | | - if strings.HasPrefix(flag, "--") { |
146 | | - flag = flag[1:] |
| 92 | + // Use fs.Set instead of f.Value.Set below so that any subsequent call to |
| 93 | + // fs.Visit will correctly visit the flags that have been set. |
| 94 | + |
| 95 | + failf := func(format string, a ...interface{}) (*flag.Flag, []string, error) { |
| 96 | + return f, args, fmt.Errorf(format, a...) |
| 97 | + } |
| 98 | + |
| 99 | + if fv, ok := f.Value.(boolFlag); ok && fv.IsBoolFlag() { // special case: doesn't need an arg |
| 100 | + if hasValue { |
| 101 | + if err := fs.Set(name, value); err != nil { |
| 102 | + return failf("invalid boolean value %q for -%s: %v", value, name, err) |
| 103 | + } |
| 104 | + } else { |
| 105 | + if err := fs.Set(name, "true"); err != nil { |
| 106 | + return failf("invalid boolean flag %s: %v", name, err) |
| 107 | + } |
147 | 108 | } |
148 | | - name := flag[1:] |
149 | | - if i := strings.Index(name, "="); i >= 0 { |
150 | | - name = name[:i] |
| 109 | + } else { |
| 110 | + // It must have a value, which might be the next argument. |
| 111 | + if !hasValue && len(args) > 0 { |
| 112 | + // value is the next arg |
| 113 | + hasValue = true |
| 114 | + value, args = args[0], args[1:] |
151 | 115 | } |
152 | | - for _, f := range defns { |
153 | | - if name == f.Name { |
154 | | - flags = append(flags, flag) |
155 | | - break |
156 | | - } |
| 116 | + if !hasValue { |
| 117 | + return failf("flag needs an argument: -%s", name) |
| 118 | + } |
| 119 | + if err := fs.Set(name, value); err != nil { |
| 120 | + return failf("invalid value %q for flag -%s: %v", value, name, err) |
157 | 121 | } |
158 | 122 | } |
159 | | - return flags |
| 123 | + |
| 124 | + return f, args, nil |
| 125 | +} |
| 126 | + |
| 127 | +type boolFlag interface { |
| 128 | + IsBoolFlag() bool |
160 | 129 | } |
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