copy go/analysis internal/checker into the project as is

use commit f0bfdbff1f9c986484a9f02fc198b1efcfe76ebe

Author: jirfag

pkg/golinters/goanalysis/analysisflags/flags.go

@@ -0,0 +1,344 @@
+// 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/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.
+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)
+	}
+
+	// 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
+		}
+	}
+
+	return analyzers
+}
+
+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 as these have no effect on unitchecker
+		// (as invoked by 'go vet').
+		switch f.Name {
+		case "debug", "cpuprofile", "memprofile", "trace":
+			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 miminal 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 {
+		data, _ := ioutil.ReadFile(posn.Filename)
+		lines := strings.Split(string(data), "\n")
+		for i := posn.Line - Context; i <= posn.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
+		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)
+}