1 files changed, 135 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/internal/modindex/directories.go b/vendor/golang.org/x/tools/internal/modindex/directories.go
new file mode 100644
index 000000000..1e1a02f23
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/modindex/directories.go
@@ -0,0 +1,135 @@
+// Copyright 2024 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 modindex
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"regexp"
+	"slices"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/mod/semver"
+	"golang.org/x/tools/internal/gopathwalk"
+)
+
+type directory struct {
+	path       Relpath
+	importPath string
+	version    string // semantic version
+	syms       []symbol
+}
+
+// filterDirs groups the directories by import path,
+// sorting the ones with the same import path by semantic version,
+// most recent first.
+func byImportPath(dirs []Relpath) (map[string][]*directory, error) {
+	ans := make(map[string][]*directory) // key is import path
+	for _, d := range dirs {
+		ip, sv, err := DirToImportPathVersion(d)
+		if err != nil {
+			return nil, err
+		}
+		ans[ip] = append(ans[ip], &directory{
+			path:       d,
+			importPath: ip,
+			version:    sv,
+		})
+	}
+	for k, v := range ans {
+		semanticSort(v)
+		ans[k] = v
+	}
+	return ans, nil
+}
+
+// sort the directories by semantic version, latest first
+func semanticSort(v []*directory) {
+	slices.SortFunc(v, func(l, r *directory) int {
+		if n := semver.Compare(l.version, r.version); n != 0 {
+			return -n // latest first
+		}
+		return strings.Compare(string(l.path), string(r.path))
+	})
+}
+
+// modCacheRegexp splits a relpathpath into module, module version, and package.
+var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`)
+
+// DirToImportPathVersion computes import path and semantic version
+func DirToImportPathVersion(dir Relpath) (string, string, error) {
+	m := modCacheRegexp.FindStringSubmatch(string(dir))
+	// m[1] is the module path
+	// m[2] is the version major.minor.patch(-<pre release identifier)
+	// m[3] is the rest of the package path
+	if len(m) != 4 {
+		return "", "", fmt.Errorf("bad dir %s", dir)
+	}
+	if !semver.IsValid(m[2]) {
+		return "", "", fmt.Errorf("bad semantic version %s", m[2])
+	}
+	// ToSlash is required for Windows.
+	return filepath.ToSlash(m[1] + m[3]), m[2], nil
+}
+
+// a region controls what directories to look at, for
+// updating the index incrementally, and for testing that.
+// (for testing one builds an index as of A, incrementally
+// updates it to B, and compares the result to an index build
+// as of B.)
+type region struct {
+	onlyAfter, onlyBefore time.Time
+	sync.Mutex
+	ans []Relpath
+}
+
+func findDirs(root string, onlyAfter, onlyBefore time.Time) []Relpath {
+	roots := []gopathwalk.Root{{Path: root, Type: gopathwalk.RootModuleCache}}
+	// TODO(PJW): adjust concurrency
+	opts := gopathwalk.Options{ModulesEnabled: true, Concurrency: 1 /* ,Logf: log.Printf*/}
+	betw := &region{
+		onlyAfter:  onlyAfter,
+		onlyBefore: onlyBefore,
+	}
+	gopathwalk.WalkSkip(roots, betw.addDir, betw.skipDir, opts)
+	return betw.ans
+}
+
+func (r *region) addDir(rt gopathwalk.Root, dir string) {
+	// do we need to check times?
+	r.Lock()
+	defer r.Unlock()
+	x := filepath.ToSlash(string(toRelpath(Abspath(rt.Path), dir)))
+	r.ans = append(r.ans, toRelpath(Abspath(rt.Path), x))
+}
+
+func (r *region) skipDir(_ gopathwalk.Root, dir string) bool {
+	// The cache directory is already ignored in gopathwalk\
+	if filepath.Base(dir) == "internal" {
+		return true
+	}
+	if strings.Contains(dir, "toolchain@") {
+		return true
+	}
+	// don't look inside @ directories that are too old
+	if strings.Contains(filepath.Base(dir), "@") {
+		st, err := os.Stat(dir)
+		if err != nil {
+			log.Printf("can't stat dir %s %v", dir, err)
+			return true
+		}
+		if st.ModTime().Before(r.onlyAfter) {
+			return true
+		}
+		if st.ModTime().After(r.onlyBefore) {
+			return true
+		}
+	}
+	return false
+}