| // Copyright 2023 The Shac Authors |
| // |
| // 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. |
| |
| package cli |
| |
| import ( |
| "context" |
| "fmt" |
| "io" |
| "log" |
| "os" |
| "strings" |
| |
| flag "github.com/spf13/pflag" |
| ) |
| |
| var helpOut io.Writer = os.Stderr |
| |
| type app struct { |
| fs *flag.FlagSet |
| help bool |
| verbose bool |
| } |
| |
| func (a *app) init(n, desc string) { |
| a.fs = flag.NewFlagSet(n, flag.ContinueOnError) |
| a.fs.SetOutput(helpOut) |
| a.fs.BoolVarP(&a.verbose, "verbose", "v", false, "Verbose output") |
| a.fs.BoolVarP(&a.help, "help", "h", false, "Prints help") |
| a.fs.Usage = func() { |
| fmt.Fprintf(helpOut, "Usage of %s:\n\n%s\n", n, desc) |
| a.fs.PrintDefaults() |
| } |
| } |
| |
| func getDesc(s []subcommand) string { |
| out := "" |
| for _, c := range s { |
| d := strings.Split(c.Description(), "\n") |
| for i := 1; i < len(d); i++ { |
| d[i] = " " + d[i] |
| } |
| out += fmt.Sprintf(" %-9s %s\n", c.Name(), strings.Join(d, "\n")) |
| } |
| return out |
| } |
| |
| type subcommand interface { |
| Name() string |
| Description() string |
| SetFlags(*flag.FlagSet) |
| Execute(ctx context.Context, args []string) error |
| } |
| |
| // Main implements shac executable. |
| func Main(args []string) error { |
| ctx := context.Background() |
| |
| subcommands := [...]subcommand{ |
| // Ordered roughly by importance, because ordering here corresponds to |
| // the order in which subcommands will be listed in `shac help`. |
| &checkCmd{}, |
| &fmtCmd{}, |
| &fixCmd{}, |
| &docCmd{}, |
| &versionCmd{}, |
| &helpCmd{}, |
| } |
| a := app{} |
| |
| if len(args) < 2 { |
| a.init("shac", getDesc(subcommands[:])) |
| a.fs.Usage() |
| return fmt.Errorf("subcommand required") |
| } |
| cmd := args[1] |
| if cmd == "help" { |
| // Special case. |
| a.init("shac", getDesc(subcommands[:])) |
| a.fs.Usage() |
| return flag.ErrHelp |
| } |
| for _, s := range subcommands { |
| if s.Name() != cmd { |
| continue |
| } |
| a.init("shac "+s.Name(), s.Description()+"\n") |
| s.SetFlags(a.fs) |
| if err := a.fs.Parse(args[2:]); err != nil { |
| return err |
| } |
| if a.help { |
| a.fs.Usage() |
| return flag.ErrHelp |
| } |
| if !a.verbose { |
| log.SetOutput(io.Discard) |
| } |
| return s.Execute(ctx, a.fs.Args()) |
| } |
| a.init("shac", getDesc(subcommands[:])) |
| if err := a.fs.Parse(args[1:]); err != nil { |
| return err |
| } |
| if a.help { |
| a.fs.Usage() |
| return flag.ErrHelp |
| } |
| return fmt.Errorf("no such command %q", args[1]) |
| } |