github.com/jhump/golang-x-tools@v0.0.0-20220218190644-4958d6d39439/go/analysis/singlechecker/singlechecker.go (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package singlechecker defines the main function for an analysis
     6  // driver with only a single analysis.
     7  // This package makes it easy for a provider of an analysis package to
     8  // also provide a standalone tool that runs just that analysis.
     9  //
    10  // For example, if example.org/findbadness is an analysis package,
    11  // all that is needed to define a standalone tool is a file,
    12  // example.org/findbadness/cmd/findbadness/main.go, containing:
    13  //
    14  // 	// The findbadness command runs an analysis.
    15  // 	package main
    16  //
    17  // 	import (
    18  // 		"example.org/findbadness"
    19  // 		"github.com/jhump/golang-x-tools/go/analysis/singlechecker"
    20  // 	)
    21  //
    22  // 	func main() { singlechecker.Main(findbadness.Analyzer) }
    23  //
    24  package singlechecker
    25  
    26  import (
    27  	"flag"
    28  	"fmt"
    29  	"log"
    30  	"os"
    31  	"strings"
    32  
    33  	"github.com/jhump/golang-x-tools/go/analysis"
    34  	"github.com/jhump/golang-x-tools/go/analysis/internal/analysisflags"
    35  	"github.com/jhump/golang-x-tools/go/analysis/internal/checker"
    36  	"github.com/jhump/golang-x-tools/go/analysis/unitchecker"
    37  )
    38  
    39  // Main is the main function for a checker command for a single analysis.
    40  func Main(a *analysis.Analyzer) {
    41  	log.SetFlags(0)
    42  	log.SetPrefix(a.Name + ": ")
    43  
    44  	analyzers := []*analysis.Analyzer{a}
    45  
    46  	if err := analysis.Validate(analyzers); err != nil {
    47  		log.Fatal(err)
    48  	}
    49  
    50  	checker.RegisterFlags()
    51  
    52  	flag.Usage = func() {
    53  		paras := strings.Split(a.Doc, "\n\n")
    54  		fmt.Fprintf(os.Stderr, "%s: %s\n\n", a.Name, paras[0])
    55  		fmt.Fprintf(os.Stderr, "Usage: %s [-flag] [package]\n\n", a.Name)
    56  		if len(paras) > 1 {
    57  			fmt.Fprintln(os.Stderr, strings.Join(paras[1:], "\n\n"))
    58  		}
    59  		fmt.Fprintln(os.Stderr, "\nFlags:")
    60  		flag.PrintDefaults()
    61  	}
    62  
    63  	analyzers = analysisflags.Parse(analyzers, false)
    64  
    65  	args := flag.Args()
    66  	if len(args) == 0 {
    67  		flag.Usage()
    68  		os.Exit(1)
    69  	}
    70  
    71  	if len(args) == 1 && strings.HasSuffix(args[0], ".cfg") {
    72  		unitchecker.Run(args[0], analyzers)
    73  		panic("unreachable")
    74  	}
    75  
    76  	os.Exit(checker.Run(args, analyzers))
    77  }