diff options
Diffstat (limited to 'vendor/golang.org/x/tools/imports/fix.go')
-rw-r--r-- | vendor/golang.org/x/tools/imports/fix.go | 1141 |
1 files changed, 1141 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/imports/fix.go b/vendor/golang.org/x/tools/imports/fix.go new file mode 100644 index 00000000..af006705 --- /dev/null +++ b/vendor/golang.org/x/tools/imports/fix.go @@ -0,0 +1,1141 @@ +// 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] == '\\' +} |