Use filesystem symlink mapping on non-windows systems.

link.go

@@ -2,7 +2,11 @@
 
 package localcache
 
-import "os"
+import (
+	"os"
+)
+
+// Simply use native symlinks everywhere but on windows.
 
 func Readlink(name string) (string, error) {
 	return os.Readlink(name)
@@ -11,3 +15,11 @@ func Readlink(name string) (string, error) {
 func Symlink(oldname, newname string) error {
 	return os.Symlink(oldname, newname)
 }
+
+func Openlink(name string) (*os.File, error) {
+	return os.Open(name)
+}
+
+func ReadlinkFile(name string) ([]byte, error) {
+	return os.ReadFile(name)
+}

link_windows.go

@@ -17,3 +17,19 @@ func Readlink(name string) (string, error) {
 func Symlink(oldname, newname string) error {
 	return os.WriteFile(newname, []byte(oldname), 0644)
 }
+
+func Openlink(name string) (*os.File, error) {
+	entry, err := Readlink(name)
+	if err != nil {
+		return nil, err
+	}
+	return os.Open(entry)
+}
+
+func ReadlinkFile(name string) ([]byte, error) {
+	entry, err := Readlink(name)
+	if err != nil {
+		return nil, err
+	}
+	return os.ReadFile(entry)
+}

localcache.go

@@ -3,7 +3,6 @@ package localcache
 import (
 	"crypto/sha256"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -240,22 +239,14 @@ func (c *Cache) IfExists(key string) string {
 func (c *Cache) Open(key string) (*os.File, error) {
 	key = hash(key, false)
 	path := filepath.Join(c.root, key[:2], key)
-	entry, err := Readlink(path)
-	if err != nil {
-		return nil, err
-	}
-	return os.Open(entry)
+	return Openlink(path)
 }
 
 // ReadFile identified by key.
 func (c *Cache) ReadFile(key string) ([]byte, error) {
 	key = hash(key, false)
 	path := filepath.Join(c.root, key[:2], key)
-	entry, err := Readlink(path)
-	if err != nil {
-		return nil, err
-	}
-	return ioutil.ReadFile(entry)
+	return ReadlinkFile(path)
 }
 
 // Purge entry for given key if older than given age.