Create new file-hash files

src/libstore/file-hash.cc

@@ -0,0 +1,27 @@
+#include "file-hash.hh"
+
+namespace nix {
+
+std::string FileSystemHash::printMethodAlgo() const {
+    return makeFileIngestionPrefix(method) + printHashType(hash.type);
+}
+
+std::string makeFileIngestionPrefix(const FileIngestionMethod m) {
+    switch (m) {
+    case FileIngestionMethod::Flat:
+        return "";
+    case FileIngestionMethod::Recursive:
+        return "r:";
+    default:
+        throw Error("impossible, caught both cases");
+    }
+}
+
+std::string makeFixedOutputCA(FileIngestionMethod method, const Hash & hash)
+{
+    return "fixed:"
+        + makeFileIngestionPrefix(method)
+        + hash.to_string();
+}
+
+}