1 files changed, 331 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/internal/gopathwalk/walk.go b/vendor/golang.org/x/tools/internal/gopathwalk/walk.go
new file mode 100644
index 000000000..52f74e643
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/gopathwalk/walk.go
@@ -0,0 +1,331 @@
+// 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 gopathwalk is like filepath.Walk but specialized for finding Go
+// packages, particularly in $GOPATH and $GOROOT.
+package gopathwalk
+
+import (
+	"bufio"
+	"bytes"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// Options controls the behavior of a Walk call.
+type Options struct {
+	// If Logf is non-nil, debug logging is enabled through this function.
+	Logf func(format string, args ...interface{})
+	// Search module caches. Also disables legacy goimports ignore rules.
+	ModulesEnabled bool
+}
+
+// RootType indicates the type of a Root.
+type RootType int
+
+const (
+	RootUnknown RootType = iota
+	RootGOROOT
+	RootGOPATH
+	RootCurrentModule
+	RootModuleCache
+	RootOther
+)
+
+// A Root is a starting point for a Walk.
+type Root struct {
+	Path string
+	Type RootType
+}
+
+// Walk walks Go source directories ($GOROOT, $GOPATH, etc) to find packages.
+// For each package found, add will be called with the absolute
+// paths of the containing source directory and the package directory.
+func Walk(roots []Root, add func(root Root, dir string), opts Options) {
+	WalkSkip(roots, add, func(Root, string) bool { return false }, opts)
+}
+
+// WalkSkip walks Go source directories ($GOROOT, $GOPATH, etc) to find packages.
+// For each package found, add will be called with the absolute
+// paths of the containing source directory and the package directory.
+// For each directory that will be scanned, skip will be called
+// with the absolute paths of the containing source directory and the directory.
+// If skip returns false on a directory it will be processed.
+func WalkSkip(roots []Root, add func(root Root, dir string), skip func(root Root, dir string) bool, opts Options) {
+	for _, root := range roots {
+		walkDir(root, add, skip, opts)
+	}
+}
+
+// walkDir creates a walker and starts fastwalk with this walker.
+func walkDir(root Root, add func(Root, string), skip func(root Root, dir string) bool, opts Options) {
+	if _, err := os.Stat(root.Path); os.IsNotExist(err) {
+		if opts.Logf != nil {
+			opts.Logf("skipping nonexistent directory: %v", root.Path)
+		}
+		return
+	}
+	start := time.Now()
+	if opts.Logf != nil {
+		opts.Logf("scanning %s", root.Path)
+	}
+
+	w := &walker{
+		root:  root,
+		add:   add,
+		skip:  skip,
+		opts:  opts,
+		added: make(map[string]bool),
+	}
+	w.init()
+
+	// Add a trailing path separator to cause filepath.WalkDir to traverse symlinks.
+	path := root.Path
+	if len(path) == 0 {
+		path = "." + string(filepath.Separator)
+	} else if !os.IsPathSeparator(path[len(path)-1]) {
+		path = path + string(filepath.Separator)
+	}
+
+	if err := filepath.WalkDir(path, w.walk); err != nil {
+		logf := opts.Logf
+		if logf == nil {
+			logf = log.Printf
+		}
+		logf("scanning directory %v: %v", root.Path, err)
+	}
+
+	if opts.Logf != nil {
+		opts.Logf("scanned %s in %v", root.Path, time.Since(start))
+	}
+}
+
+// walker is the callback for fastwalk.Walk.
+type walker struct {
+	root Root                    // The source directory to scan.
+	add  func(Root, string)      // The callback that will be invoked for every possible Go package dir.
+	skip func(Root, string) bool // The callback that will be invoked for every dir. dir is skipped if it returns true.
+	opts Options                 // Options passed to Walk by the user.
+
+	pathSymlinks []os.FileInfo
+	ignoredDirs  []string
+
+	added map[string]bool
+}
+
+// init initializes the walker based on its Options
+func (w *walker) init() {
+	var ignoredPaths []string
+	if w.root.Type == RootModuleCache {
+		ignoredPaths = []string{"cache"}
+	}
+	if !w.opts.ModulesEnabled && w.root.Type == RootGOPATH {
+		ignoredPaths = w.getIgnoredDirs(w.root.Path)
+		ignoredPaths = append(ignoredPaths, "v", "mod")
+	}
+
+	for _, p := range ignoredPaths {
+		full := filepath.Join(w.root.Path, p)
+		w.ignoredDirs = append(w.ignoredDirs, full)
+		if w.opts.Logf != nil {
+			w.opts.Logf("Directory added to ignore list: %s", full)
+		}
+	}
+}
+
+// getIgnoredDirs 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 (w *walker) getIgnoredDirs(path string) []string {
+	file := filepath.Join(path, ".goimportsignore")
+	slurp, err := os.ReadFile(file)
+	if w.opts.Logf != nil {
+		if err != nil {
+			w.opts.Logf("%v", err)
+		} else {
+			w.opts.Logf("Read %s", file)
+		}
+	}
+	if err != nil {
+		return nil
+	}
+
+	var ignoredDirs []string
+	bs := bufio.NewScanner(bytes.NewReader(slurp))
+	for bs.Scan() {
+		line := strings.TrimSpace(bs.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		ignoredDirs = append(ignoredDirs, line)
+	}
+	return ignoredDirs
+}
+
+// shouldSkipDir reports whether the file should be skipped or not.
+func (w *walker) shouldSkipDir(dir string) bool {
+	for _, ignoredDir := range w.ignoredDirs {
+		if dir == ignoredDir {
+			return true
+		}
+	}
+	if w.skip != nil {
+		// Check with the user specified callback.
+		return w.skip(w.root, dir)
+	}
+	return false
+}
+
+// walk walks through the given path.
+//
+// Errors are logged if w.opts.Logf is non-nil, but otherwise ignored:
+// walk returns only nil or fs.SkipDir.
+func (w *walker) walk(path string, d fs.DirEntry, err error) error {
+	if err != nil {
+		// We have no way to report errors back through Walk or WalkSkip,
+		// so just log and ignore them.
+		if w.opts.Logf != nil {
+			w.opts.Logf("%v", err)
+		}
+		if d == nil {
+			// Nothing more to do: the error prevents us from knowing
+			// what path even represents.
+			return nil
+		}
+	}
+
+	if d.Type().IsRegular() {
+		if !strings.HasSuffix(path, ".go") {
+			return nil
+		}
+
+		dir := filepath.Dir(path)
+		if dir == w.root.Path && (w.root.Type == RootGOROOT || w.root.Type == RootGOPATH) {
+			// Doesn't make sense to have regular files
+			// directly in your $GOPATH/src or $GOROOT/src.
+			return nil
+		}
+
+		if !w.added[dir] {
+			w.add(w.root, dir)
+			w.added[dir] = true
+		}
+		return nil
+	}
+
+	if d.IsDir() {
+		base := filepath.Base(path)
+		if base == "" || base[0] == '.' || base[0] == '_' ||
+			base == "testdata" ||
+			(w.root.Type == RootGOROOT && w.opts.ModulesEnabled && base == "vendor") ||
+			(!w.opts.ModulesEnabled && base == "node_modules") {
+			return fs.SkipDir
+		}
+		if w.shouldSkipDir(path) {
+			return fs.SkipDir
+		}
+		return nil
+	}
+
+	if d.Type()&os.ModeSymlink != 0 {
+		// TODO(bcmills): 'go list all' itself ignores symlinks within GOROOT/src
+		// and GOPATH/src. Do we really need to traverse them here? If so, why?
+
+		fi, err := os.Stat(path)
+		if err != nil || !fi.IsDir() {
+			// Not a directory. Just walk the file (or broken link) and be done.
+			return w.walk(path, fs.FileInfoToDirEntry(fi), err)
+		}
+
+		// Avoid walking symlink cycles: if we have already followed a symlink to
+		// this directory as a parent of itself, don't follow it again.
+		//
+		// This doesn't catch the first time through a cycle, but it also minimizes
+		// the number of extra stat calls we make if we *don't* encounter a cycle.
+		// Since we don't actually expect to encounter symlink cycles in practice,
+		// this seems like the right tradeoff.
+		for _, parent := range w.pathSymlinks {
+			if os.SameFile(fi, parent) {
+				return nil
+			}
+		}
+
+		w.pathSymlinks = append(w.pathSymlinks, fi)
+		defer func() {
+			w.pathSymlinks = w.pathSymlinks[:len(w.pathSymlinks)-1]
+		}()
+
+		// On some platforms the OS (or the Go os package) sometimes fails to
+		// resolve directory symlinks before a trailing slash
+		// (even though POSIX requires it to do so).
+		//
+		// On macOS that failure may be caused by a known libc/kernel bug;
+		// see https://go.dev/issue/59586.
+		//
+		// On Windows before Go 1.21, it may be caused by a bug in
+		// os.Lstat (fixed in https://go.dev/cl/463177).
+		//
+		// Since we need to handle this explicitly on broken platforms anyway,
+		// it is simplest to just always do that and not rely on POSIX pathname
+		// resolution to walk the directory (such as by calling WalkDir with
+		// a trailing slash appended to the path).
+		//
+		// Instead, we make a sequence of walk calls — directly and through
+		// recursive calls to filepath.WalkDir — simulating what WalkDir would do
+		// if the symlink were a regular directory.
+
+		// First we call walk on the path as a directory
+		// (instead of a symlink).
+		err = w.walk(path, fs.FileInfoToDirEntry(fi), nil)
+		if err == fs.SkipDir {
+			return nil
+		} else if err != nil {
+			// This should be impossible, but handle it anyway in case
+			// walk is changed to return other errors.
+			return err
+		}
+
+		// Now read the directory and walk its entries.
+		ents, err := os.ReadDir(path)
+		if err != nil {
+			// Report the ReadDir error, as filepath.WalkDir would do.
+			err = w.walk(path, fs.FileInfoToDirEntry(fi), err)
+			if err == fs.SkipDir {
+				return nil
+			} else if err != nil {
+				return err // Again, should be impossible.
+			}
+			// Fall through and iterate over whatever entries we did manage to get.
+		}
+
+		for _, d := range ents {
+			nextPath := filepath.Join(path, d.Name())
+			if d.IsDir() {
+				// We want to walk the whole directory tree rooted at nextPath,
+				// not just the single entry for the directory.
+				err := filepath.WalkDir(nextPath, w.walk)
+				if err != nil && w.opts.Logf != nil {
+					w.opts.Logf("%v", err)
+				}
+			} else {
+				err := w.walk(nextPath, d, nil)
+				if err == fs.SkipDir {
+					// Skip the rest of the entries in the parent directory of nextPath
+					// (that is, path itself).
+					break
+				} else if err != nil {
+					return err // Again, should be impossible.
+				}
+			}
+		}
+		return nil
+	}
+
+	// Not a file, regular directory, or symlink; skip.
+	return nil
+}