types/model: make Name.Filepath substitute colons in host with ("%")

This makes the filepath legal on all supported platforms.

Fixes #4088

server/fixblobs.go

@@ -3,6 +3,7 @@ package server
 import (
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 )
 
@@ -24,3 +25,44 @@ func fixBlobs(dir string) error {
 		return nil
 	})
 }
+
+// fixManifests walks the provided dir and replaces (":") to ("%") for all
+// manifest files on non-Windows systems.
+func fixManifests(dir string) error {
+	if runtime.GOOS == "windows" {
+		return nil
+	}
+	return filepath.Walk(dir, func(oldPath string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+
+		var partNum int
+		newPath := []byte(oldPath)
+		for i := len(newPath) - 1; i >= 0; i-- {
+			if partNum > 3 {
+				break
+			}
+			if partNum == 3 {
+				if newPath[i] == ':' {
+					newPath[i] = '%'
+					break
+				}
+				continue
+			}
+			if newPath[i] == '/' {
+				partNum++
+			}
+		}
+
+		newDir, _ := filepath.Split(string(newPath))
+		if err := os.MkdirAll(newDir, 0o755); err != nil {
+			return err
+		}
+
+		return os.Rename(oldPath, string(newPath))
+	})
+}