go/analysis/internal/analysisflags/flags.go - tools - Git at Google

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // Package analysisflags defines helpers for processing flags of
 // analysis driver tools.
 package analysisflags

 import (
 	"crypto/sha256"
 	"encoding/gob"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"go/token"
 	"io"
 	"io/ioutil"
 	"log"
 	"os"
 	"strconv"
 	"strings"

 	"golang.org/x/tools/go/analysis"
 )

 // flags common to all {single,multi,unit}checkers.
 var (
 	JSON    = false // -json
 	Context = -1    // -c=N: if N>0, display offending line plus N lines of context
 )

 // Parse creates a flag for each of the analyzer's flags,
 // including (in multi mode) a flag named after the analyzer,
 // parses the flags, then filters and returns the list of
 // analyzers enabled by flags.
 //
 // The result is intended to be passed to unitchecker.Run or checker.Run.
 // Use in unitchecker.Run will gob.Register all fact types for the returned
 // graph of analyzers but of course not the ones only reachable from
 // dropped analyzers. To avoid inconsistency about which gob types are
 // registered from run to run, Parse itself gob.Registers all the facts
 // only reachable from dropped analyzers.
 // This is not a particularly elegant API, but this is an internal package.
 func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
 	// Connect each analysis flag to the command line as -analysis.flag.
 	enabled := make(map[*analysis.Analyzer]*triState)
 	for _, a := range analyzers {
 		var prefix string

 		// Add -NAME flag to enable it.
 		if multi {
 			prefix = a.Name + "."

 			enable := new(triState)
 			enableUsage := "enable " + a.Name + " analysis"
 			flag.Var(enable, a.Name, enableUsage)
 			enabled[a] = enable
 		}

 		a.Flags.VisitAll(func(f *flag.Flag) {
 			if !multi && flag.Lookup(f.Name) != nil {
 				log.Printf("%s flag -%s would conflict with driver; skipping", a.Name, f.Name)
 				return
 			}

 			name := prefix + f.Name
 			flag.Var(f.Value, name, f.Usage)
 		})
 	}

 	// standard flags: -flags, -V.
 	printflags := flag.Bool("flags", false, "print analyzer flags in JSON")
 	addVersionFlag()

 	// flags common to all checkers
 	flag.BoolVar(&JSON, "json", JSON, "emit JSON output")
 	flag.IntVar(&Context, "c", Context, `display offending line with this many lines of context`)

 	// Add shims for legacy vet flags to enable existing
 	// scripts that run vet to continue to work.
 	_ = flag.Bool("source", false, "no effect (deprecated)")
 	_ = flag.Bool("v", false, "no effect (deprecated)")
 	_ = flag.Bool("all", false, "no effect (deprecated)")
 	_ = flag.String("tags", "", "no effect (deprecated)")
 	for old, new := range vetLegacyFlags {
 		newFlag := flag.Lookup(new)
 		if newFlag != nil && flag.Lookup(old) == nil {
 			flag.Var(newFlag.Value, old, "deprecated alias for -"+new)
 		}
 	}

 	flag.Parse() // (ExitOnError)

 	// -flags: print flags so that go vet knows which ones are legitimate.
 	if *printflags {
 		printFlags()
 		os.Exit(0)
 	}

 	everything := expand(analyzers)

 	// If any -NAME flag is true,  run only those analyzers. Otherwise,
 	// if any -NAME flag is false, run all but those analyzers.
 	if multi {
 		var hasTrue, hasFalse bool
 		for _, ts := range enabled {
 			switch *ts {
 			case setTrue:
 				hasTrue = true
 			case setFalse:
 				hasFalse = true
 			}
 		}

 		var keep []*analysis.Analyzer
 		if hasTrue {
 			for _, a := range analyzers {
 				if *enabled[a] == setTrue {
 					keep = append(keep, a)
 				}
 			}
 			analyzers = keep
 		} else if hasFalse {
 			for _, a := range analyzers {
 				if *enabled[a] != setFalse {
 					keep = append(keep, a)
 				}
 			}
 			analyzers = keep
 		}
 	}

 	// Register fact types of skipped analyzers
 	// in case we encounter them in imported files.
 	kept := expand(analyzers)
 	for a := range everything {
 		if !kept[a] {
 			for _, f := range a.FactTypes {
 				gob.Register(f)
 			}
 		}
 	}

 	return analyzers
 }

 func expand(analyzers []*analysis.Analyzer) map[*analysis.Analyzer]bool {
 	seen := make(map[*analysis.Analyzer]bool)
 	var visitAll func([]*analysis.Analyzer)
 	visitAll = func(analyzers []*analysis.Analyzer) {
 		for _, a := range analyzers {
 			if !seen[a] {
 				seen[a] = true
 				visitAll(a.Requires)
 			}
 		}
 	}
 	visitAll(analyzers)
 	return seen
 }

 func printFlags() {
 	type jsonFlag struct {
 		Name  string
 		Bool  bool
 		Usage string
 	}
 	var flags []jsonFlag = nil
 	flag.VisitAll(func(f *flag.Flag) {
 		// Don't report {single,multi}checker debugging
 		// flags or fix as these have no effect on unitchecker
 		// (as invoked by 'go vet').
 		switch f.Name {
 		case "debug", "cpuprofile", "memprofile", "trace", "fix":
 			return
 		}

 		b, ok := f.Value.(interface{ IsBoolFlag() bool })
 		isBool := ok && b.IsBoolFlag()
 		flags = append(flags, jsonFlag{f.Name, isBool, f.Usage})
 	})
 	data, err := json.MarshalIndent(flags, "", "\t")
 	if err != nil {
 		log.Fatal(err)
 	}
 	os.Stdout.Write(data)
 }

 // addVersionFlag registers a -V flag that, if set,
 // prints the executable version and exits 0.
 //
 // If the -V flag already exists — for example, because it was already
 // registered by a call to cmd/internal/objabi.AddVersionFlag — then
 // addVersionFlag does nothing.
 func addVersionFlag() {
 	if flag.Lookup("V") == nil {
 		flag.Var(versionFlag{}, "V", "print version and exit")
 	}
 }

 // versionFlag minimally complies with the -V protocol required by "go vet".
 type versionFlag struct{}

 func (versionFlag) IsBoolFlag() bool { return true }
 func (versionFlag) Get() interface{} { return nil }
 func (versionFlag) String() string   { return "" }
 func (versionFlag) Set(s string) error {
 	if s != "full" {
 		log.Fatalf("unsupported flag value: -V=%s", s)
 	}

 	// This replicates the minimal subset of
 	// cmd/internal/objabi.AddVersionFlag, which is private to the
 	// go tool yet forms part of our command-line interface.
 	// TODO(adonovan): clarify the contract.

 	// Print the tool version so the build system can track changes.
 	// Formats:
 	//   $progname version devel ... buildID=...
 	//   $progname version go1.9.1
 	progname := os.Args[0]
 	f, err := os.Open(progname)
 	if err != nil {
 		log.Fatal(err)
 	}
 	h := sha256.New()
 	if _, err := io.Copy(h, f); err != nil {
 		log.Fatal(err)
 	}
 	f.Close()
 	fmt.Printf("%s version devel comments-go-here buildID=%02x\n",
 		progname, string(h.Sum(nil)))
 	os.Exit(0)
 	return nil
 }

 // A triState is a boolean that knows whether
 // it has been set to either true or false.
 // It is used to identify whether a flag appears;
 // the standard boolean flag cannot
 // distinguish missing from unset.
 // It also satisfies flag.Value.
 type triState int

 const (
 	unset triState = iota
 	setTrue
 	setFalse
 )

 func triStateFlag(name string, value triState, usage string) *triState {
 	flag.Var(&value, name, usage)
 	return &value
 }

 // triState implements flag.Value, flag.Getter, and flag.boolFlag.
 // They work like boolean flags: we can say vet -printf as well as vet -printf=true
 func (ts *triState) Get() interface{} {
 	return *ts == setTrue
 }

 func (ts triState) isTrue() bool {
 	return ts == setTrue
 }

 func (ts *triState) Set(value string) error {
 	b, err := strconv.ParseBool(value)
 	if err != nil {
 		// This error message looks poor but package "flag" adds
 		// "invalid boolean value %q for -NAME: %s"
 		return fmt.Errorf("want true or false")
 	}
 	if b {
 		*ts = setTrue
 	} else {
 		*ts = setFalse
 	}
 	return nil
 }

 func (ts *triState) String() string {
 	switch *ts {
 	case unset:
 		return "true"
 	case setTrue:
 		return "true"
 	case setFalse:
 		return "false"
 	}
 	panic("not reached")
 }

 func (ts triState) IsBoolFlag() bool {
 	return true
 }

 // Legacy flag support

 // vetLegacyFlags maps flags used by legacy vet to their corresponding
 // new names. The old names will continue to work.
 var vetLegacyFlags = map[string]string{
 	// Analyzer name changes
 	"bool":       "bools",
 	"buildtags":  "buildtag",
 	"methods":    "stdmethods",
 	"rangeloops": "loopclosure",

 	// Analyzer flags
 	"compositewhitelist":  "composites.whitelist",
 	"printfuncs":          "printf.funcs",
 	"shadowstrict":        "shadow.strict",
 	"unusedfuncs":         "unusedresult.funcs",
 	"unusedstringmethods": "unusedresult.stringmethods",
 }

 // ---- output helpers common to all drivers ----

 // PrintPlain prints a diagnostic in plain text form,
 // with context specified by the -c flag.
 func PrintPlain(fset *token.FileSet, diag analysis.Diagnostic) {
 	posn := fset.Position(diag.Pos)
 	fmt.Fprintf(os.Stderr, "%s: %s\n", posn, diag.Message)

 	// -c=N: show offending line plus N lines of context.
 	if Context >= 0 {
 		posn := fset.Position(diag.Pos)
 		end := fset.Position(diag.End)
 		if !end.IsValid() {
 			end = posn
 		}
 		data, _ := ioutil.ReadFile(posn.Filename)
 		lines := strings.Split(string(data), "\n")
 		for i := posn.Line - Context; i <= end.Line+Context; i++ {
 			if 1 <= i && i <= len(lines) {
 				fmt.Fprintf(os.Stderr, "%d\t%s\n", i, lines[i-1])
 			}
 		}
 	}
 }

 // A JSONTree is a mapping from package ID to analysis name to result.
 // Each result is either a jsonError or a list of jsonDiagnostic.
 type JSONTree map[string]map[string]interface{}

 // Add adds the result of analysis 'name' on package 'id'.
 // The result is either a list of diagnostics or an error.
 func (tree JSONTree) Add(fset *token.FileSet, id, name string, diags []analysis.Diagnostic, err error) {
 	var v interface{}
 	if err != nil {
 		type jsonError struct {
 			Err string `json:"error"`
 		}
 		v = jsonError{err.Error()}
 	} else if len(diags) > 0 {
 		type jsonDiagnostic struct {
 			Category string `json:"category,omitempty"`
 			Posn     string `json:"posn"`
 			Message  string `json:"message"`
 		}
 		var diagnostics []jsonDiagnostic
 		// TODO(matloob): Should the JSON diagnostics contain ranges?
 		// If so, how should they be formatted?
 		for _, f := range diags {
 			diagnostics = append(diagnostics, jsonDiagnostic{
 				Category: f.Category,
 				Posn:     fset.Position(f.Pos).String(),
 				Message:  f.Message,
 			})
 		}
 		v = diagnostics
 	}
 	if v != nil {
 		m, ok := tree[id]
 		if !ok {
 			m = make(map[string]interface{})
 			tree[id] = m
 		}
 		m[name] = v
 	}
 }

 func (tree JSONTree) Print() {
 	data, err := json.MarshalIndent(tree, "", "\t")
 	if err != nil {
 		log.Panicf("internal error: JSON marshalling failed: %v", err)
 	}
 	fmt.Printf("%s\n", data)
 }
	// Copyright 2018 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// Package analysisflags defines helpers for processing flags of
	// analysis driver tools.
	package analysisflags

	import (
	"crypto/sha256"
	"encoding/gob"
	"encoding/json"
	"flag"
	"fmt"
	"go/token"
	"io"
	"io/ioutil"
	"log"
	"os"
	"strconv"
	"strings"

	"golang.org/x/tools/go/analysis"
	)

	// flags common to all {single,multi,unit}checkers.
	var (
	JSON = false // -json
	Context = -1 // -c=N: if N>0, display offending line plus N lines of context
	)

	// Parse creates a flag for each of the analyzer's flags,
	// including (in multi mode) a flag named after the analyzer,
	// parses the flags, then filters and returns the list of
	// analyzers enabled by flags.
	//
	// The result is intended to be passed to unitchecker.Run or checker.Run.
	// Use in unitchecker.Run will gob.Register all fact types for the returned
	// graph of analyzers but of course not the ones only reachable from
	// dropped analyzers. To avoid inconsistency about which gob types are
	// registered from run to run, Parse itself gob.Registers all the facts
	// only reachable from dropped analyzers.
	// This is not a particularly elegant API, but this is an internal package.
	func Parse(analyzers []analysis.Analyzer, multi bool) []analysis.Analyzer {
	// Connect each analysis flag to the command line as -analysis.flag.
	enabled := make(map[analysis.Analyzer]triState)
	for _, a := range analyzers {
	var prefix string

	// Add -NAME flag to enable it.
	if multi {
	prefix = a.Name + "."

	enable := new(triState)
	enableUsage := "enable " + a.Name + " analysis"
	flag.Var(enable, a.Name, enableUsage)
	enabled[a] = enable
	}

	a.Flags.VisitAll(func(f *flag.Flag) {
	if !multi && flag.Lookup(f.Name) != nil {
	log.Printf("%s flag -%s would conflict with driver; skipping", a.Name, f.Name)
	return
	}

	name := prefix + f.Name
	flag.Var(f.Value, name, f.Usage)
	})
	}

	// standard flags: -flags, -V.
	printflags := flag.Bool("flags", false, "print analyzer flags in JSON")
	addVersionFlag()

	// flags common to all checkers
	flag.BoolVar(&JSON, "json", JSON, "emit JSON output")
	flag.IntVar(&Context, "c", Context, `display offending line with this many lines of context`)

	// Add shims for legacy vet flags to enable existing
	// scripts that run vet to continue to work.
	_ = flag.Bool("source", false, "no effect (deprecated)")
	_ = flag.Bool("v", false, "no effect (deprecated)")
	_ = flag.Bool("all", false, "no effect (deprecated)")
	_ = flag.String("tags", "", "no effect (deprecated)")
	for old, new := range vetLegacyFlags {
	newFlag := flag.Lookup(new)
	if newFlag != nil && flag.Lookup(old) == nil {
	flag.Var(newFlag.Value, old, "deprecated alias for -"+new)
	}
	}

	flag.Parse() // (ExitOnError)

	// -flags: print flags so that go vet knows which ones are legitimate.
	if *printflags {
	printFlags()
	os.Exit(0)
	}

	everything := expand(analyzers)

	// If any -NAME flag is true, run only those analyzers. Otherwise,
	// if any -NAME flag is false, run all but those analyzers.
	if multi {
	var hasTrue, hasFalse bool
	for _, ts := range enabled {
	switch *ts {
	case setTrue:
	hasTrue = true
	case setFalse:
	hasFalse = true
	}
	}

	var keep []*analysis.Analyzer
	if hasTrue {
	for _, a := range analyzers {
	if *enabled[a] == setTrue {
	keep = append(keep, a)
	}
	}
	analyzers = keep
	} else if hasFalse {
	for _, a := range analyzers {
	if *enabled[a] != setFalse {
	keep = append(keep, a)
	}
	}
	analyzers = keep
	}
	}

	// Register fact types of skipped analyzers
	// in case we encounter them in imported files.
	kept := expand(analyzers)
	for a := range everything {
	if !kept[a] {
	for _, f := range a.FactTypes {
	gob.Register(f)
	}
	}
	}

	return analyzers
	}

	func expand(analyzers []analysis.Analyzer) map[analysis.Analyzer]bool {
	seen := make(map[*analysis.Analyzer]bool)
	var visitAll func([]*analysis.Analyzer)
	visitAll = func(analyzers []*analysis.Analyzer) {
	for _, a := range analyzers {
	if !seen[a] {
	seen[a] = true
	visitAll(a.Requires)
	}
	}
	}
	visitAll(analyzers)
	return seen
	}

	func printFlags() {
	type jsonFlag struct {
	Name string
	Bool bool
	Usage string
	}
	var flags []jsonFlag = nil
	flag.VisitAll(func(f *flag.Flag) {
	// Don't report {single,multi}checker debugging
	// flags or fix as these have no effect on unitchecker
	// (as invoked by 'go vet').
	switch f.Name {
	case "debug", "cpuprofile", "memprofile", "trace", "fix":
	return
	}

	b, ok := f.Value.(interface{ IsBoolFlag() bool })
	isBool := ok && b.IsBoolFlag()
	flags = append(flags, jsonFlag{f.Name, isBool, f.Usage})
	})
	data, err := json.MarshalIndent(flags, "", "\t")
	if err != nil {
	log.Fatal(err)
	}
	os.Stdout.Write(data)
	}

	// addVersionFlag registers a -V flag that, if set,
	// prints the executable version and exits 0.
	//
	// If the -V flag already exists — for example, because it was already
	// registered by a call to cmd/internal/objabi.AddVersionFlag — then
	// addVersionFlag does nothing.
	func addVersionFlag() {
	if flag.Lookup("V") == nil {
	flag.Var(versionFlag{}, "V", "print version and exit")
	}
	}

	// versionFlag minimally complies with the -V protocol required by "go vet".
	type versionFlag struct{}

	func (versionFlag) IsBoolFlag() bool { return true }
	func (versionFlag) Get() interface{} { return nil }
	func (versionFlag) String() string { return "" }
	func (versionFlag) Set(s string) error {
	if s != "full" {
	log.Fatalf("unsupported flag value: -V=%s", s)
	}

	// This replicates the minimal subset of
	// cmd/internal/objabi.AddVersionFlag, which is private to the
	// go tool yet forms part of our command-line interface.
	// TODO(adonovan): clarify the contract.

	// Print the tool version so the build system can track changes.
	// Formats:
	// $progname version devel ... buildID=...
	// $progname version go1.9.1
	progname := os.Args[0]
	f, err := os.Open(progname)
	if err != nil {
	log.Fatal(err)
	}
	h := sha256.New()
	if _, err := io.Copy(h, f); err != nil {
	log.Fatal(err)
	}
	f.Close()
	fmt.Printf("%s version devel comments-go-here buildID=%02x\n",
	progname, string(h.Sum(nil)))
	os.Exit(0)
	return nil
	}

	// A triState is a boolean that knows whether
	// it has been set to either true or false.
	// It is used to identify whether a flag appears;
	// the standard boolean flag cannot
	// distinguish missing from unset.
	// It also satisfies flag.Value.
	type triState int

	const (
	unset triState = iota
	setTrue
	setFalse
	)

	func triStateFlag(name string, value triState, usage string) *triState {
	flag.Var(&value, name, usage)
	return &value
	}

	// triState implements flag.Value, flag.Getter, and flag.boolFlag.
	// They work like boolean flags: we can say vet -printf as well as vet -printf=true
	func (ts *triState) Get() interface{} {
	return *ts == setTrue
	}

	func (ts triState) isTrue() bool {
	return ts == setTrue
	}

	func (ts *triState) Set(value string) error {
	b, err := strconv.ParseBool(value)
	if err != nil {
	// This error message looks poor but package "flag" adds
	// "invalid boolean value %q for -NAME: %s"
	return fmt.Errorf("want true or false")
	}
	if b {
	*ts = setTrue
	} else {
	*ts = setFalse
	}
	return nil
	}

	func (ts *triState) String() string {
	switch *ts {
	case unset:
	return "true"
	case setTrue:
	return "true"
	case setFalse:
	return "false"
	}
	panic("not reached")
	}

	func (ts triState) IsBoolFlag() bool {
	return true
	}

	// Legacy flag support

	// vetLegacyFlags maps flags used by legacy vet to their corresponding
	// new names. The old names will continue to work.
	var vetLegacyFlags = map[string]string{
	// Analyzer name changes
	"bool": "bools",
	"buildtags": "buildtag",
	"methods": "stdmethods",
	"rangeloops": "loopclosure",

	// Analyzer flags
	"compositewhitelist": "composites.whitelist",
	"printfuncs": "printf.funcs",
	"shadowstrict": "shadow.strict",
	"unusedfuncs": "unusedresult.funcs",
	"unusedstringmethods": "unusedresult.stringmethods",
	}

	// ---- output helpers common to all drivers ----

	// PrintPlain prints a diagnostic in plain text form,
	// with context specified by the -c flag.
	func PrintPlain(fset *token.FileSet, diag analysis.Diagnostic) {
	posn := fset.Position(diag.Pos)
	fmt.Fprintf(os.Stderr, "%s: %s\n", posn, diag.Message)

	// -c=N: show offending line plus N lines of context.
	if Context >= 0 {
	posn := fset.Position(diag.Pos)
	end := fset.Position(diag.End)
	if !end.IsValid() {
	end = posn
	}
	data, _ := ioutil.ReadFile(posn.Filename)
	lines := strings.Split(string(data), "\n")
	for i := posn.Line - Context; i <= end.Line+Context; i++ {
	if 1 <= i && i <= len(lines) {
	fmt.Fprintf(os.Stderr, "%d\t%s\n", i, lines[i-1])
	}
	}
	}
	}

	// A JSONTree is a mapping from package ID to analysis name to result.
	// Each result is either a jsonError or a list of jsonDiagnostic.
	type JSONTree map[string]map[string]interface{}

	// Add adds the result of analysis 'name' on package 'id'.
	// The result is either a list of diagnostics or an error.
	func (tree JSONTree) Add(fset *token.FileSet, id, name string, diags []analysis.Diagnostic, err error) {
	var v interface{}
	if err != nil {
	type jsonError struct {
	Err string `json:"error"`
	}
	v = jsonError{err.Error()}
	} else if len(diags) > 0 {
	type jsonDiagnostic struct {
	Category string `json:"category,omitempty"`
	Posn string `json:"posn"`
	Message string `json:"message"`
	}
	var diagnostics []jsonDiagnostic
	// TODO(matloob): Should the JSON diagnostics contain ranges?
	// If so, how should they be formatted?
	for _, f := range diags {
	diagnostics = append(diagnostics, jsonDiagnostic{
	Category: f.Category,
	Posn: fset.Position(f.Pos).String(),
	Message: f.Message,
	})
	}
	v = diagnostics
	}
	if v != nil {
	m, ok := tree[id]
	if !ok {
	m = make(map[string]interface{})
	tree[id] = m
	}
	m[name] = v
	}
	}

	func (tree JSONTree) Print() {
	data, err := json.MarshalIndent(tree, "", "\t")
	if err != nil {
	log.Panicf("internal error: JSON marshalling failed: %v", err)
	}
	fmt.Printf("%s\n", data)
	}