1 files changed, 78 insertions, 0 deletions
diff --git a/src/cmd/go/internal/toolchain/path_windows.go b/src/cmd/go/internal/toolchain/path_windows.go
new file mode 100644
index 0000000..086c591
--- /dev/null
+++ b/src/cmd/go/internal/toolchain/path_windows.go
@@ -0,0 +1,78 @@
+// Copyright 2023 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 toolchain
+
+import (
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"cmd/go/internal/gover"
+)
+
+// pathExts is a cached PATHEXT list.
+var pathExts struct {
+	once sync.Once
+	list []string
+}
+
+func initPathExts() {
+	var exts []string
+	x := os.Getenv(`PATHEXT`)
+	if x != "" {
+		for _, e := range strings.Split(strings.ToLower(x), `;`) {
+			if e == "" {
+				continue
+			}
+			if e[0] != '.' {
+				e = "." + e
+			}
+			exts = append(exts, e)
+		}
+	} else {
+		exts = []string{".com", ".exe", ".bat", ".cmd"}
+	}
+	pathExts.list = exts
+}
+
+// pathDirs returns the directories in the system search path.
+func pathDirs() []string {
+	return filepath.SplitList(os.Getenv("PATH"))
+}
+
+// pathVersion returns the Go version implemented by the file
+// described by de and info in directory dir.
+// The analysis only uses the name itself; it does not run the program.
+func pathVersion(dir string, de fs.DirEntry, info fs.FileInfo) (string, bool) {
+	pathExts.once.Do(initPathExts)
+	name, _, ok := cutExt(de.Name(), pathExts.list)
+	if !ok {
+		return "", false
+	}
+	v := gover.FromToolchain(name)
+	if v == "" {
+		return "", false
+	}
+	return v, true
+}
+
+// cutExt looks for any of the known extensions at the end of file.
+// If one is found, cutExt returns the file name with the extension trimmed,
+// the extension itself, and true to signal that an extension was found.
+// Otherwise cutExt returns file, "", false.
+func cutExt(file string, exts []string) (name, ext string, found bool) {
+	i := strings.LastIndex(file, ".")
+	if i < 0 {
+		return file, "", false
+	}
+	for _, x := range exts {
+		if strings.EqualFold(file[i:], x) {
+			return file[:i], file[i:], true
+		}
+	}
+	return file, "", false
+}