ipld-eth-server/vendor/golang.org/x/tools/imports/fix.go
Rob Mulholand 560305f601 Update dependencies
- uses newer version of go-ethereum required for go1.11
2018-09-13 16:14:35 -05:00

1142 lines
30 KiB
Go

// Copyright 2013 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 imports
import (
"bufio"
"bytes"
"context"
"fmt"
"go/ast"
"go/build"
"go/parser"
"go/token"
"io/ioutil"
"log"
"os"
"path"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/internal/fastwalk"
)
// Debug controls verbose logging.
var Debug = false
// LocalPrefix is a comma-separated string of import path prefixes, which, if
// set, instructs Process to sort the import paths with the given prefixes
// into another group after 3rd-party packages.
var LocalPrefix string
func localPrefixes() []string {
if LocalPrefix != "" {
return strings.Split(LocalPrefix, ",")
}
return nil
}
// importToGroup is a list of functions which map from an import path to
// a group number.
var importToGroup = []func(importPath string) (num int, ok bool){
func(importPath string) (num int, ok bool) {
for _, p := range localPrefixes() {
if strings.HasPrefix(importPath, p) || strings.TrimSuffix(p, "/") == importPath {
return 3, true
}
}
return
},
func(importPath string) (num int, ok bool) {
if strings.HasPrefix(importPath, "appengine") {
return 2, true
}
return
},
func(importPath string) (num int, ok bool) {
if strings.Contains(importPath, ".") {
return 1, true
}
return
},
}
func importGroup(importPath string) int {
for _, fn := range importToGroup {
if n, ok := fn(importPath); ok {
return n
}
}
return 0
}
// importInfo is a summary of information about one import.
type importInfo struct {
Path string // full import path (e.g. "crypto/rand")
Alias string // import alias, if present (e.g. "crand")
}
// packageInfo is a summary of features found in a package.
type packageInfo struct {
Globals map[string]bool // symbol => true
Imports map[string]importInfo // pkg base name or alias => info
// refs are a set of package references currently satisfied by imports.
// first key: either base package (e.g. "fmt") or renamed package
// second key: referenced package symbol (e.g. "Println")
Refs map[string]map[string]bool
}
// dirPackageInfo exposes the dirPackageInfoFile function so that it can be overridden.
var dirPackageInfo = dirPackageInfoFile
// dirPackageInfoFile gets information from other files in the package.
func dirPackageInfoFile(pkgName, srcDir, filename string) (*packageInfo, error) {
considerTests := strings.HasSuffix(filename, "_test.go")
fileBase := filepath.Base(filename)
packageFileInfos, err := ioutil.ReadDir(srcDir)
if err != nil {
return nil, err
}
info := &packageInfo{
Globals: make(map[string]bool),
Imports: make(map[string]importInfo),
Refs: make(map[string]map[string]bool),
}
visitor := collectReferences(info.Refs)
for _, fi := range packageFileInfos {
if fi.Name() == fileBase || !strings.HasSuffix(fi.Name(), ".go") {
continue
}
if !considerTests && strings.HasSuffix(fi.Name(), "_test.go") {
continue
}
fileSet := token.NewFileSet()
root, err := parser.ParseFile(fileSet, filepath.Join(srcDir, fi.Name()), nil, 0)
if err != nil {
continue
}
for _, decl := range root.Decls {
genDecl, ok := decl.(*ast.GenDecl)
if !ok {
continue
}
for _, spec := range genDecl.Specs {
valueSpec, ok := spec.(*ast.ValueSpec)
if !ok {
continue
}
info.Globals[valueSpec.Names[0].Name] = true
}
}
for _, imp := range root.Imports {
impInfo := importInfo{Path: strings.Trim(imp.Path.Value, `"`)}
name := path.Base(impInfo.Path)
if imp.Name != nil {
name = strings.Trim(imp.Name.Name, `"`)
impInfo.Alias = name
}
info.Imports[name] = impInfo
}
ast.Walk(visitor, root)
}
return info, nil
}
// collectReferences returns a visitor that collects all exported package
// references
func collectReferences(refs map[string]map[string]bool) visitFn {
var visitor visitFn
visitor = func(node ast.Node) ast.Visitor {
if node == nil {
return visitor
}
switch v := node.(type) {
case *ast.SelectorExpr:
xident, ok := v.X.(*ast.Ident)
if !ok {
break
}
if xident.Obj != nil {
// if the parser can resolve it, it's not a package ref
break
}
pkgName := xident.Name
r := refs[pkgName]
if r == nil {
r = make(map[string]bool)
refs[pkgName] = r
}
if ast.IsExported(v.Sel.Name) {
r[v.Sel.Name] = true
}
}
return visitor
}
return visitor
}
func fixImports(fset *token.FileSet, f *ast.File, filename string) (added []string, err error) {
// refs are a set of possible package references currently unsatisfied by imports.
// first key: either base package (e.g. "fmt") or renamed package
// second key: referenced package symbol (e.g. "Println")
refs := make(map[string]map[string]bool)
// decls are the current package imports. key is base package or renamed package.
decls := make(map[string]*ast.ImportSpec)
abs, err := filepath.Abs(filename)
if err != nil {
return nil, err
}
srcDir := filepath.Dir(abs)
if Debug {
log.Printf("fixImports(filename=%q), abs=%q, srcDir=%q ...", filename, abs, srcDir)
}
var packageInfo *packageInfo
var loadedPackageInfo bool
// collect potential uses of packages.
var visitor visitFn
visitor = visitFn(func(node ast.Node) ast.Visitor {
if node == nil {
return visitor
}
switch v := node.(type) {
case *ast.ImportSpec:
if v.Name != nil {
decls[v.Name.Name] = v
break
}
ipath := strings.Trim(v.Path.Value, `"`)
if ipath == "C" {
break
}
local := importPathToName(ipath, srcDir)
decls[local] = v
case *ast.SelectorExpr:
xident, ok := v.X.(*ast.Ident)
if !ok {
break
}
if xident.Obj != nil {
// if the parser can resolve it, it's not a package ref
break
}
pkgName := xident.Name
if refs[pkgName] == nil {
refs[pkgName] = make(map[string]bool)
}
if !loadedPackageInfo {
loadedPackageInfo = true
packageInfo, _ = dirPackageInfo(f.Name.Name, srcDir, filename)
}
if decls[pkgName] == nil && (packageInfo == nil || !packageInfo.Globals[pkgName]) {
refs[pkgName][v.Sel.Name] = true
}
}
return visitor
})
ast.Walk(visitor, f)
// Nil out any unused ImportSpecs, to be removed in following passes
unusedImport := map[string]string{}
for pkg, is := range decls {
if refs[pkg] == nil && pkg != "_" && pkg != "." {
name := ""
if is.Name != nil {
name = is.Name.Name
}
unusedImport[strings.Trim(is.Path.Value, `"`)] = name
}
}
for ipath, name := range unusedImport {
if ipath == "C" {
// Don't remove cgo stuff.
continue
}
astutil.DeleteNamedImport(fset, f, name, ipath)
}
for pkgName, symbols := range refs {
if len(symbols) == 0 {
// skip over packages already imported
delete(refs, pkgName)
}
}
// Fast path, all references already imported.
if len(refs) == 0 {
return nil, nil
}
// Can assume this will be necessary in all cases now.
if !loadedPackageInfo {
packageInfo, _ = dirPackageInfo(f.Name.Name, srcDir, filename)
}
// Search for imports matching potential package references.
type result struct {
ipath string // import path
name string // optional name to rename import as
}
results := make(chan result, len(refs))
ctx, cancel := context.WithCancel(context.TODO())
var wg sync.WaitGroup
defer func() {
cancel()
wg.Wait()
}()
var (
firstErr error
firstErrOnce sync.Once
)
for pkgName, symbols := range refs {
wg.Add(1)
go func(pkgName string, symbols map[string]bool) {
defer wg.Done()
if packageInfo != nil {
sibling := packageInfo.Imports[pkgName]
if sibling.Path != "" {
refs := packageInfo.Refs[pkgName]
for symbol := range symbols {
if refs[symbol] {
results <- result{ipath: sibling.Path, name: sibling.Alias}
return
}
}
}
}
ipath, rename, err := findImport(ctx, pkgName, symbols, filename)
if err != nil {
firstErrOnce.Do(func() {
firstErr = err
cancel()
})
return
}
if ipath == "" {
return // No matching package.
}
r := result{ipath: ipath}
if rename {
r.name = pkgName
}
results <- r
return
}(pkgName, symbols)
}
go func() {
wg.Wait()
close(results)
}()
for result := range results {
if result.name != "" {
astutil.AddNamedImport(fset, f, result.name, result.ipath)
} else {
astutil.AddImport(fset, f, result.ipath)
}
added = append(added, result.ipath)
}
if firstErr != nil {
return nil, firstErr
}
return added, nil
}
// importPathToName returns the package name for the given import path.
var importPathToName func(importPath, srcDir string) (packageName string) = importPathToNameGoPath
// importPathToNameBasic assumes the package name is the base of import path,
// except that if the path ends in foo/vN, it assumes the package name is foo.
func importPathToNameBasic(importPath, srcDir string) (packageName string) {
base := path.Base(importPath)
if strings.HasPrefix(base, "v") {
if _, err := strconv.Atoi(base[1:]); err == nil {
dir := path.Dir(importPath)
if dir != "." {
return path.Base(dir)
}
}
}
return base
}
// importPathToNameGoPath finds out the actual package name, as declared in its .go files.
// If there's a problem, it falls back to using importPathToNameBasic.
func importPathToNameGoPath(importPath, srcDir string) (packageName string) {
// Fast path for standard library without going to disk.
if pkg, ok := stdImportPackage[importPath]; ok {
return pkg
}
pkgName, err := importPathToNameGoPathParse(importPath, srcDir)
if Debug {
log.Printf("importPathToNameGoPathParse(%q, srcDir=%q) = %q, %v", importPath, srcDir, pkgName, err)
}
if err == nil {
return pkgName
}
return importPathToNameBasic(importPath, srcDir)
}
// importPathToNameGoPathParse is a faster version of build.Import if
// the only thing desired is the package name. It uses build.FindOnly
// to find the directory and then only parses one file in the package,
// trusting that the files in the directory are consistent.
func importPathToNameGoPathParse(importPath, srcDir string) (packageName string, err error) {
buildPkg, err := build.Import(importPath, srcDir, build.FindOnly)
if err != nil {
return "", err
}
d, err := os.Open(buildPkg.Dir)
if err != nil {
return "", err
}
names, err := d.Readdirnames(-1)
d.Close()
if err != nil {
return "", err
}
sort.Strings(names) // to have predictable behavior
var lastErr error
var nfile int
for _, name := range names {
if !strings.HasSuffix(name, ".go") {
continue
}
if strings.HasSuffix(name, "_test.go") {
continue
}
nfile++
fullFile := filepath.Join(buildPkg.Dir, name)
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, fullFile, nil, parser.PackageClauseOnly)
if err != nil {
lastErr = err
continue
}
pkgName := f.Name.Name
if pkgName == "documentation" {
// Special case from go/build.ImportDir, not
// handled by ctx.MatchFile.
continue
}
if pkgName == "main" {
// Also skip package main, assuming it's a +build ignore generator or example.
// Since you can't import a package main anyway, there's no harm here.
continue
}
return pkgName, nil
}
if lastErr != nil {
return "", lastErr
}
return "", fmt.Errorf("no importable package found in %d Go files", nfile)
}
var stdImportPackage = map[string]string{} // "net/http" => "http"
func init() {
// Nothing in the standard library has a package name not
// matching its import base name.
for _, pkg := range stdlib {
if _, ok := stdImportPackage[pkg]; !ok {
stdImportPackage[pkg] = path.Base(pkg)
}
}
}
// Directory-scanning state.
var (
// scanGoRootOnce guards calling scanGoRoot (for $GOROOT)
scanGoRootOnce sync.Once
// scanGoPathOnce guards calling scanGoPath (for $GOPATH)
scanGoPathOnce sync.Once
// populateIgnoreOnce guards calling populateIgnore
populateIgnoreOnce sync.Once
ignoredDirs []os.FileInfo
dirScanMu sync.Mutex
dirScan map[string]*pkg // abs dir path => *pkg
)
type pkg struct {
dir string // absolute file path to pkg directory ("/usr/lib/go/src/net/http")
importPath string // full pkg import path ("net/http", "foo/bar/vendor/a/b")
importPathShort string // vendorless import path ("net/http", "a/b")
}
type pkgDistance struct {
pkg *pkg
distance int // relative distance to target
}
// byDistanceOrImportPathShortLength sorts by relative distance breaking ties
// on the short import path length and then the import string itself.
type byDistanceOrImportPathShortLength []pkgDistance
func (s byDistanceOrImportPathShortLength) Len() int { return len(s) }
func (s byDistanceOrImportPathShortLength) Less(i, j int) bool {
di, dj := s[i].distance, s[j].distance
if di == -1 {
return false
}
if dj == -1 {
return true
}
if di != dj {
return di < dj
}
vi, vj := s[i].pkg.importPathShort, s[j].pkg.importPathShort
if len(vi) != len(vj) {
return len(vi) < len(vj)
}
return vi < vj
}
func (s byDistanceOrImportPathShortLength) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func distance(basepath, targetpath string) int {
p, err := filepath.Rel(basepath, targetpath)
if err != nil {
return -1
}
if p == "." {
return 0
}
return strings.Count(p, string(filepath.Separator)) + 1
}
// guarded by populateIgnoreOnce; populates ignoredDirs.
func populateIgnore() {
for _, srcDir := range build.Default.SrcDirs() {
if srcDir == filepath.Join(build.Default.GOROOT, "src") {
continue
}
populateIgnoredDirs(srcDir)
}
}
// populateIgnoredDirs reads an optional config file at <path>/.goimportsignore
// of relative directories to ignore when scanning for go files.
// The provided path is one of the $GOPATH entries with "src" appended.
func populateIgnoredDirs(path string) {
file := filepath.Join(path, ".goimportsignore")
slurp, err := ioutil.ReadFile(file)
if Debug {
if err != nil {
log.Print(err)
} else {
log.Printf("Read %s", file)
}
}
if err != nil {
return
}
bs := bufio.NewScanner(bytes.NewReader(slurp))
for bs.Scan() {
line := strings.TrimSpace(bs.Text())
if line == "" || strings.HasPrefix(line, "#") {
continue
}
full := filepath.Join(path, line)
if fi, err := os.Stat(full); err == nil {
ignoredDirs = append(ignoredDirs, fi)
if Debug {
log.Printf("Directory added to ignore list: %s", full)
}
} else if Debug {
log.Printf("Error statting entry in .goimportsignore: %v", err)
}
}
}
func skipDir(fi os.FileInfo) bool {
for _, ignoredDir := range ignoredDirs {
if os.SameFile(fi, ignoredDir) {
return true
}
}
return false
}
// shouldTraverse reports whether the symlink fi, found in dir,
// should be followed. It makes sure symlinks were never visited
// before to avoid symlink loops.
func shouldTraverse(dir string, fi os.FileInfo) bool {
path := filepath.Join(dir, fi.Name())
target, err := filepath.EvalSymlinks(path)
if err != nil {
return false
}
ts, err := os.Stat(target)
if err != nil {
fmt.Fprintln(os.Stderr, err)
return false
}
if !ts.IsDir() {
return false
}
if skipDir(ts) {
return false
}
// Check for symlink loops by statting each directory component
// and seeing if any are the same file as ts.
for {
parent := filepath.Dir(path)
if parent == path {
// Made it to the root without seeing a cycle.
// Use this symlink.
return true
}
parentInfo, err := os.Stat(parent)
if err != nil {
return false
}
if os.SameFile(ts, parentInfo) {
// Cycle. Don't traverse.
return false
}
path = parent
}
}
var testHookScanDir = func(dir string) {}
type goDirType string
const (
goRoot goDirType = "$GOROOT"
goPath goDirType = "$GOPATH"
)
var scanGoRootDone = make(chan struct{}) // closed when scanGoRoot is done
// scanGoDirs populates the dirScan map for the given directory type. It may be
// called concurrently (and usually is, if both directory types are needed).
func scanGoDirs(which goDirType) {
if Debug {
log.Printf("scanning %s", which)
defer log.Printf("scanned %s", which)
}
for _, srcDir := range build.Default.SrcDirs() {
isGoroot := srcDir == filepath.Join(build.Default.GOROOT, "src")
if isGoroot != (which == goRoot) {
continue
}
testHookScanDir(srcDir)
srcV := filepath.Join(srcDir, "v")
srcMod := filepath.Join(srcDir, "mod")
walkFn := func(path string, typ os.FileMode) error {
if path == srcV || path == srcMod {
return filepath.SkipDir
}
dir := filepath.Dir(path)
if typ.IsRegular() {
if dir == srcDir {
// Doesn't make sense to have regular files
// directly in your $GOPATH/src or $GOROOT/src.
return nil
}
if !strings.HasSuffix(path, ".go") {
return nil
}
dirScanMu.Lock()
defer dirScanMu.Unlock()
if _, dup := dirScan[dir]; dup {
return nil
}
if dirScan == nil {
dirScan = make(map[string]*pkg)
}
importpath := filepath.ToSlash(dir[len(srcDir)+len("/"):])
dirScan[dir] = &pkg{
importPath: importpath,
importPathShort: VendorlessPath(importpath),
dir: dir,
}
return nil
}
if typ == os.ModeDir {
base := filepath.Base(path)
if base == "" || base[0] == '.' || base[0] == '_' ||
base == "testdata" || base == "node_modules" {
return filepath.SkipDir
}
fi, err := os.Lstat(path)
if err == nil && skipDir(fi) {
if Debug {
log.Printf("skipping directory %q under %s", fi.Name(), dir)
}
return filepath.SkipDir
}
return nil
}
if typ == os.ModeSymlink {
base := filepath.Base(path)
if strings.HasPrefix(base, ".#") {
// Emacs noise.
return nil
}
fi, err := os.Lstat(path)
if err != nil {
// Just ignore it.
return nil
}
if shouldTraverse(dir, fi) {
return fastwalk.TraverseLink
}
}
return nil
}
if err := fastwalk.Walk(srcDir, walkFn); err != nil {
log.Printf("goimports: scanning directory %v: %v", srcDir, err)
}
}
}
// VendorlessPath returns the devendorized version of the import path ipath.
// For example, VendorlessPath("foo/bar/vendor/a/b") returns "a/b".
func VendorlessPath(ipath string) string {
// Devendorize for use in import statement.
if i := strings.LastIndex(ipath, "/vendor/"); i >= 0 {
return ipath[i+len("/vendor/"):]
}
if strings.HasPrefix(ipath, "vendor/") {
return ipath[len("vendor/"):]
}
return ipath
}
// loadExports returns the set of exported symbols in the package at dir.
// It returns nil on error or if the package name in dir does not match expectPackage.
var loadExports func(ctx context.Context, expectPackage, dir string) (map[string]bool, error) = loadExportsGoPath
func loadExportsGoPath(ctx context.Context, expectPackage, dir string) (map[string]bool, error) {
if Debug {
log.Printf("loading exports in dir %s (seeking package %s)", dir, expectPackage)
}
exports := make(map[string]bool)
buildCtx := build.Default
// ReadDir is like ioutil.ReadDir, but only returns *.go files
// and filters out _test.go files since they're not relevant
// and only slow things down.
buildCtx.ReadDir = func(dir string) (notTests []os.FileInfo, err error) {
all, err := ioutil.ReadDir(dir)
if err != nil {
return nil, err
}
notTests = all[:0]
for _, fi := range all {
name := fi.Name()
if strings.HasSuffix(name, ".go") && !strings.HasSuffix(name, "_test.go") {
notTests = append(notTests, fi)
}
}
return notTests, nil
}
files, err := buildCtx.ReadDir(dir)
if err != nil {
log.Print(err)
return nil, err
}
fset := token.NewFileSet()
for _, fi := range files {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
match, err := buildCtx.MatchFile(dir, fi.Name())
if err != nil || !match {
continue
}
fullFile := filepath.Join(dir, fi.Name())
f, err := parser.ParseFile(fset, fullFile, nil, 0)
if err != nil {
if Debug {
log.Printf("Parsing %s: %v", fullFile, err)
}
return nil, err
}
pkgName := f.Name.Name
if pkgName == "documentation" {
// Special case from go/build.ImportDir, not
// handled by buildCtx.MatchFile.
continue
}
if pkgName != expectPackage {
err := fmt.Errorf("scan of dir %v is not expected package %v (actually %v)", dir, expectPackage, pkgName)
if Debug {
log.Print(err)
}
return nil, err
}
for name := range f.Scope.Objects {
if ast.IsExported(name) {
exports[name] = true
}
}
}
if Debug {
exportList := make([]string, 0, len(exports))
for k := range exports {
exportList = append(exportList, k)
}
sort.Strings(exportList)
log.Printf("loaded exports in dir %v (package %v): %v", dir, expectPackage, strings.Join(exportList, ", "))
}
return exports, nil
}
// findImport searches for a package with the given symbols.
// If no package is found, findImport returns ("", false, nil)
//
// This is declared as a variable rather than a function so goimports
// can be easily extended by adding a file with an init function.
//
// The rename value tells goimports whether to use the package name as
// a local qualifier in an import. For example, if findImports("pkg",
// "X") returns ("foo/bar", rename=true), then goimports adds the
// import line:
// import pkg "foo/bar"
// to satisfy uses of pkg.X in the file.
var findImport func(ctx context.Context, pkgName string, symbols map[string]bool, filename string) (foundPkg string, rename bool, err error) = findImportGoPath
// findImportGoPath is the normal implementation of findImport.
// (Some companies have their own internally.)
func findImportGoPath(ctx context.Context, pkgName string, symbols map[string]bool, filename string) (foundPkg string, rename bool, err error) {
pkgDir, err := filepath.Abs(filename)
if err != nil {
return "", false, err
}
pkgDir = filepath.Dir(pkgDir)
// Fast path for the standard library.
// In the common case we hopefully never have to scan the GOPATH, which can
// be slow with moving disks.
if pkg, ok := findImportStdlib(pkgName, symbols); ok {
return pkg, false, nil
}
if pkgName == "rand" && symbols["Read"] {
// Special-case rand.Read.
//
// If findImportStdlib didn't find it above, don't go
// searching for it, lest it find and pick math/rand
// in GOROOT (new as of Go 1.6)
//
// crypto/rand is the safer choice.
return "", false, nil
}
// TODO(sameer): look at the import lines for other Go files in the
// local directory, since the user is likely to import the same packages
// in the current Go file. Return rename=true when the other Go files
// use a renamed package that's also used in the current file.
// Read all the $GOPATH/src/.goimportsignore files before scanning directories.
populateIgnoreOnce.Do(populateIgnore)
// Start scanning the $GOROOT asynchronously, then run the
// GOPATH scan synchronously if needed, and then wait for the
// $GOROOT to finish.
//
// TODO(bradfitz): run each $GOPATH entry async. But nobody
// really has more than one anyway, so low priority.
scanGoRootOnce.Do(func() {
go func() {
scanGoDirs(goRoot)
close(scanGoRootDone)
}()
})
if !fileInDir(filename, build.Default.GOROOT) {
scanGoPathOnce.Do(func() { scanGoDirs(goPath) })
}
<-scanGoRootDone
// Find candidate packages, looking only at their directory names first.
var candidates []pkgDistance
for _, pkg := range dirScan {
if pkgIsCandidate(filename, pkgName, pkg) {
candidates = append(candidates, pkgDistance{
pkg: pkg,
distance: distance(pkgDir, pkg.dir),
})
}
}
// Sort the candidates by their import package length,
// assuming that shorter package names are better than long
// ones. Note that this sorts by the de-vendored name, so
// there's no "penalty" for vendoring.
sort.Sort(byDistanceOrImportPathShortLength(candidates))
if Debug {
for i, c := range candidates {
log.Printf("%s candidate %d/%d: %v in %v", pkgName, i+1, len(candidates), c.pkg.importPathShort, c.pkg.dir)
}
}
// Collect exports for packages with matching names.
rescv := make([]chan *pkg, len(candidates))
for i := range candidates {
rescv[i] = make(chan *pkg, 1)
}
const maxConcurrentPackageImport = 4
loadExportsSem := make(chan struct{}, maxConcurrentPackageImport)
ctx, cancel := context.WithCancel(ctx)
var wg sync.WaitGroup
defer func() {
cancel()
wg.Wait()
}()
wg.Add(1)
go func() {
defer wg.Done()
for i, c := range candidates {
select {
case loadExportsSem <- struct{}{}:
case <-ctx.Done():
return
}
wg.Add(1)
go func(c pkgDistance, resc chan<- *pkg) {
defer func() {
<-loadExportsSem
wg.Done()
}()
exports, err := loadExports(ctx, pkgName, c.pkg.dir)
if err != nil {
resc <- nil
return
}
// If it doesn't have the right
// symbols, send nil to mean no match.
for symbol := range symbols {
if !exports[symbol] {
resc <- nil
return
}
}
resc <- c.pkg
}(c, rescv[i])
}
}()
for _, resc := range rescv {
pkg := <-resc
if pkg == nil {
continue
}
// If the package name in the source doesn't match the import path's base,
// return true so the rewriter adds a name (import foo "github.com/bar/go-foo")
needsRename := path.Base(pkg.importPath) != pkgName
return pkg.importPathShort, needsRename, nil
}
return "", false, nil
}
// pkgIsCandidate reports whether pkg is a candidate for satisfying the
// finding which package pkgIdent in the file named by filename is trying
// to refer to.
//
// This check is purely lexical and is meant to be as fast as possible
// because it's run over all $GOPATH directories to filter out poor
// candidates in order to limit the CPU and I/O later parsing the
// exports in candidate packages.
//
// filename is the file being formatted.
// pkgIdent is the package being searched for, like "client" (if
// searching for "client.New")
func pkgIsCandidate(filename, pkgIdent string, pkg *pkg) bool {
// Check "internal" and "vendor" visibility:
if !canUse(filename, pkg.dir) {
return false
}
// Speed optimization to minimize disk I/O:
// the last two components on disk must contain the
// package name somewhere.
//
// This permits mismatch naming like directory
// "go-foo" being package "foo", or "pkg.v3" being "pkg",
// or directory "google.golang.org/api/cloudbilling/v1"
// being package "cloudbilling", but doesn't
// permit a directory "foo" to be package
// "bar", which is strongly discouraged
// anyway. There's no reason goimports needs
// to be slow just to accommodate that.
lastTwo := lastTwoComponents(pkg.importPathShort)
if strings.Contains(lastTwo, pkgIdent) {
return true
}
if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(pkgIdent) {
lastTwo = lowerASCIIAndRemoveHyphen(lastTwo)
if strings.Contains(lastTwo, pkgIdent) {
return true
}
}
return false
}
func hasHyphenOrUpperASCII(s string) bool {
for i := 0; i < len(s); i++ {
b := s[i]
if b == '-' || ('A' <= b && b <= 'Z') {
return true
}
}
return false
}
func lowerASCIIAndRemoveHyphen(s string) (ret string) {
buf := make([]byte, 0, len(s))
for i := 0; i < len(s); i++ {
b := s[i]
switch {
case b == '-':
continue
case 'A' <= b && b <= 'Z':
buf = append(buf, b+('a'-'A'))
default:
buf = append(buf, b)
}
}
return string(buf)
}
// canUse reports whether the package in dir is usable from filename,
// respecting the Go "internal" and "vendor" visibility rules.
func canUse(filename, dir string) bool {
// Fast path check, before any allocations. If it doesn't contain vendor
// or internal, it's not tricky:
// Note that this can false-negative on directories like "notinternal",
// but we check it correctly below. This is just a fast path.
if !strings.Contains(dir, "vendor") && !strings.Contains(dir, "internal") {
return true
}
dirSlash := filepath.ToSlash(dir)
if !strings.Contains(dirSlash, "/vendor/") && !strings.Contains(dirSlash, "/internal/") && !strings.HasSuffix(dirSlash, "/internal") {
return true
}
// Vendor or internal directory only visible from children of parent.
// That means the path from the current directory to the target directory
// can contain ../vendor or ../internal but not ../foo/vendor or ../foo/internal
// or bar/vendor or bar/internal.
// After stripping all the leading ../, the only okay place to see vendor or internal
// is at the very beginning of the path.
absfile, err := filepath.Abs(filename)
if err != nil {
return false
}
absdir, err := filepath.Abs(dir)
if err != nil {
return false
}
rel, err := filepath.Rel(absfile, absdir)
if err != nil {
return false
}
relSlash := filepath.ToSlash(rel)
if i := strings.LastIndex(relSlash, "../"); i >= 0 {
relSlash = relSlash[i+len("../"):]
}
return !strings.Contains(relSlash, "/vendor/") && !strings.Contains(relSlash, "/internal/") && !strings.HasSuffix(relSlash, "/internal")
}
// lastTwoComponents returns at most the last two path components
// of v, using either / or \ as the path separator.
func lastTwoComponents(v string) string {
nslash := 0
for i := len(v) - 1; i >= 0; i-- {
if v[i] == '/' || v[i] == '\\' {
nslash++
if nslash == 2 {
return v[i:]
}
}
}
return v
}
type visitFn func(node ast.Node) ast.Visitor
func (fn visitFn) Visit(node ast.Node) ast.Visitor {
return fn(node)
}
func findImportStdlib(shortPkg string, symbols map[string]bool) (importPath string, ok bool) {
for symbol := range symbols {
key := shortPkg + "." + symbol
path := stdlib[key]
if path == "" {
if key == "rand.Read" {
continue
}
return "", false
}
if importPath != "" && importPath != path {
// Ambiguous. Symbols pointed to different things.
return "", false
}
importPath = path
}
if importPath == "" && shortPkg == "rand" && symbols["Read"] {
return "crypto/rand", true
}
return importPath, importPath != ""
}
// fileInDir reports whether the provided file path looks like
// it's in dir. (without hitting the filesystem)
func fileInDir(file, dir string) bool {
rest := strings.TrimPrefix(file, dir)
if len(rest) == len(file) {
// dir is not a prefix of file.
return false
}
// Check for boundary: either nothing (file == dir), or a slash.
return len(rest) == 0 || rest[0] == '/' || rest[0] == '\\'
}