github.com/cockroachdb/tools@v0.0.0-20230222021103-a6d27438930d/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  //		"golang.org/x/tools/go/analysis/singlechecker"
    20  //	)
    21  //
    22  //	func main() { singlechecker.Main(findbadness.Analyzer) }
    23  package singlechecker
    24  
    25  import (
    26  	"flag"
    27  	"fmt"
    28  	"log"
    29  	"os"
    30  	"strings"
    31  
    32  	"golang.org/x/tools/go/analysis"
    33  	"golang.org/x/tools/go/analysis/internal/analysisflags"
    34  	"golang.org/x/tools/go/analysis/internal/checker"
    35  	"golang.org/x/tools/go/analysis/unitchecker"
    36  )
    37  
    38  // Main is the main function for a checker command for a single analysis.
    39  func Main(a *analysis.Analyzer) {
    40  	log.SetFlags(0)
    41  	log.SetPrefix(a.Name + ": ")
    42  
    43  	analyzers := []*analysis.Analyzer{a}
    44  
    45  	if err := analysis.Validate(analyzers); err != nil {
    46  		log.Fatal(err)
    47  	}
    48  
    49  	checker.RegisterFlags()
    50  
    51  	flag.Usage = func() {
    52  		paras := strings.Split(a.Doc, "\n\n")
    53  		fmt.Fprintf(os.Stderr, "%s: %s\n\n", a.Name, paras[0])
    54  		fmt.Fprintf(os.Stderr, "Usage: %s [-flag] [package]\n\n", a.Name)
    55  		if len(paras) > 1 {
    56  			fmt.Fprintln(os.Stderr, strings.Join(paras[1:], "\n\n"))
    57  		}
    58  		fmt.Fprintln(os.Stderr, "\nFlags:")
    59  		flag.PrintDefaults()
    60  	}
    61  
    62  	analyzers = analysisflags.Parse(analyzers, false)
    63  
    64  	args := flag.Args()
    65  	if len(args) == 0 {
    66  		flag.Usage()
    67  		os.Exit(1)
    68  	}
    69  
    70  	if len(args) == 1 && strings.HasSuffix(args[0], ".cfg") {
    71  		unitchecker.Run(args[0], analyzers)
    72  		panic("unreachable")
    73  	}
    74  
    75  	os.Exit(checker.Run(args, analyzers))
    76  }