public void write(Encoder encoder, VersionRef value) throws Exception {
            GitVersionRef gitRef = (GitVersionRef) value;
            encoder.writeString(gitRef.getVersion());
            encoder.writeString(gitRef.getCanonicalId());
        }

        @Override
        public VersionRef read(Decoder decoder) throws Exception {
            String version = decoder.readString();
            String canonicalId = decoder.readString();

                        String prefix = repoName.length() <= 9 ? repoName : repoName.substring(0, 10);
                        String versionId = prefix + "_" + hashString(getUniqueId() + "-" + ref.getCanonicalId()).toCompactString();
                        File baseDir = new File(cacheAccess.getBaseDir(), versionId);
                        File workingDir = new File(baseDir, repoName);