Files
llgo/cmd/internal/base/base.go
xushiwei a1211a98e3 cmd/llgo
2023-12-11 09:53:40 +08:00

115 lines
3.1 KiB
Go

/*
* Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
*
* 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 base defines shared basic pieces of the llgo command,
// in particular logging and the Command structure.
package base
import (
"flag"
"fmt"
"io"
"os"
"strings"
)
// A Command is an implementation of a gop command
// like gop export or gop install.
type Command struct {
// Run runs the command.
// The args are the arguments after the command name.
Run func(cmd *Command, args []string)
// UsageLine is the one-line usage message.
// The words between "gop" and the first flag or argument in the line are taken to be the command name.
UsageLine string
// Short is the short description shown in the 'gop help' output.
Short string
// Flag is a set of flags specific to this command.
Flag flag.FlagSet
// Commands lists the available commands and help topics.
// The order here is the order in which they are printed by 'gop help'.
// Note that subcommands are in general best avoided.
Commands []*Command
}
// Llgo command
var Llgo = &Command{
UsageLine: "llgo",
Short: `llgo is a Go compiler based on LLVM in order to better integrate Go with the C ecosystem.`,
// Commands initialized in package main
}
// LongName returns the command's long name: all the words in the usage line between "gop" and a flag or argument,
func (c *Command) LongName() string {
name := c.UsageLine
if i := strings.Index(name, " ["); i >= 0 {
name = name[:i]
}
if name == "llgo" {
return ""
}
return strings.TrimPrefix(name, "llgo ")
}
// Name returns the command's short name: the last word in the usage line before a flag or argument.
func (c *Command) Name() string {
name := c.LongName()
if i := strings.LastIndex(name, " "); i >= 0 {
name = name[i+1:]
}
return name
}
// Usage show the command usage.
func (c *Command) Usage(w io.Writer) {
fmt.Fprintf(w, "%s\n\nUsage: %s\n", c.Short, c.UsageLine)
// restore output of flag
defer c.Flag.SetOutput(c.Flag.Output())
c.Flag.SetOutput(w)
c.Flag.PrintDefaults()
fmt.Fprintln(w)
os.Exit(2)
}
// Runnable reports whether the command can be run; otherwise
// it is a documentation pseudo-command.
func (c *Command) Runnable() bool {
return c.Run != nil
}
// Usage is the usage-reporting function, filled in by package main
// but here for reference by other packages.
//
// flag.Usage func()
// CmdName - "build", "install", "list", "mod tidy", etc.
var CmdName string
// Main runs a command.
func Main(c *Command, app string, args []string) {
name := c.UsageLine
if i := strings.Index(name, " ["); i >= 0 {
c.UsageLine = app + name[i:]
}
c.Run(c, args)
}