125 lines
2.9 KiB
Go
125 lines
2.9 KiB
Go
/*
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* Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Package help implements the “llgo help” command.
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package help
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import (
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"bufio"
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"fmt"
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"io"
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"log"
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"os"
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"strings"
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"text/template"
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"unicode"
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"unicode/utf8"
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"github.com/goplus/llgo/compiler/cmd/internal/base"
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"github.com/goplus/llgo/compiler/internal/mockable"
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)
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// Help implements the 'help' command.
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func Help(w io.Writer, args []string) {
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cmd := base.Llgo
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Args:
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for i, arg := range args {
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for _, sub := range cmd.Commands {
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if sub.Name() == arg {
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cmd = sub
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continue Args
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}
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}
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// helpSuccess is the help command using as many args as possible that would succeed.
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helpSuccess := "llgo help"
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if i > 0 {
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helpSuccess += " " + strings.Join(args[:i], " ")
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}
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fmt.Fprintf(os.Stderr, "llgo help %s: unknown help topic. Run '%s'.\n", strings.Join(args, " "), helpSuccess)
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mockable.Exit(2)
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}
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if len(cmd.Commands) > 0 {
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PrintUsage(w, cmd)
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} else {
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cmd.Usage(w)
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}
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// not exit 2: succeeded at 'llgo help cmd'.
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}
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var usageTemplate = `{{.Short | trim}}
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Usage:
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{{.UsageLine}} <command> [arguments]
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The commands are:
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{{range .Commands}}{{if or (.Runnable) .Commands}}
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{{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
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Use "llgo help{{with .LongName}} {{.}}{{end}} <command>" for more information about a command.
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`
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// An errWriter wraps a writer, recording whether a write error occurred.
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type errWriter struct {
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w io.Writer
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err error
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}
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func (w *errWriter) Write(b []byte) (int, error) {
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n, err := w.w.Write(b)
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if err != nil {
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w.err = err
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}
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return n, err
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}
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// tmpl executes the given template text on data, writing the result to w.
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func tmpl(w io.Writer, text string, data interface{}) {
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t := template.New("top")
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t.Funcs(template.FuncMap{"trim": strings.TrimSpace, "capitalize": capitalize})
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template.Must(t.Parse(text))
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ew := &errWriter{w: w}
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err := t.Execute(ew, data)
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if ew.err != nil {
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// I/O error writing. Ignore write on closed pipe.
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if strings.Contains(ew.err.Error(), "pipe") {
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mockable.Exit(1)
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}
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log.Fatalf("writing output: %v", ew.err)
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}
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if err != nil {
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panic(err)
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}
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}
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func capitalize(s string) string {
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if s == "" {
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return s
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}
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r, n := utf8.DecodeRuneInString(s)
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return string(unicode.ToTitle(r)) + s[n:]
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}
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// PrintUsage prints usage information.
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func PrintUsage(w io.Writer, cmd *base.Command) {
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bw := bufio.NewWriter(w)
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tmpl(bw, usageTemplate, cmd)
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bw.Flush()
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}
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