1 files changed, 21 insertions, 2 deletions
diff --git a/icing/store/document-store.h b/icing/store/document-store.h
index 3e02636..7c414d7 100644
--- a/icing/store/document-store.h
+++ b/icing/store/document-store.h
@@ -59,13 +59,19 @@ namespace lib {
 class DocumentStore {
  public:
   struct Header {
-    static constexpr int32_t kMagic = 0x746f7265;
+    static int32_t GetCurrentMagic(bool namespace_id_fingerprint) {
+      return namespace_id_fingerprint ? kNewMagic : kOldMagic;
+    }
 
     // Holds the magic as a quick sanity check against file corruption.
     int32_t magic;
 
     // Checksum of the DocumentStore's sub-component's checksums.
     uint32_t checksum;
+
+   private:
+    static constexpr int32_t kOldMagic = 0x746f7265;
+    static constexpr int32_t kNewMagic = 0x1b99c8b0;
   };
 
   struct OptimizeInfo {
@@ -136,6 +142,7 @@ class DocumentStore {
       const Filesystem* filesystem, const std::string& base_dir,
       const Clock* clock, const SchemaStore* schema_store,
       bool force_recovery_and_revalidate_documents = false,
+      bool namespace_id_fingerprint = false,
       InitializeStatsProto* initialize_stats = nullptr);
 
   // Returns the maximum DocumentId that the DocumentStore has assigned. If
@@ -472,7 +479,8 @@ class DocumentStore {
  private:
   // Use DocumentStore::Create() to instantiate.
   DocumentStore(const Filesystem* filesystem, std::string_view base_dir,
-                const Clock* clock, const SchemaStore* schema_store);
+                const Clock* clock, const SchemaStore* schema_store,
+                bool namespace_id_fingerprint);
 
   const Filesystem* const filesystem_;
   const std::string base_dir_;
@@ -485,6 +493,10 @@ class DocumentStore {
   // Used to validate incoming documents
   DocumentValidator document_validator_;
 
+  // Whether to use namespace id or namespace name to build up fingerprint for
+  // document_key_mapper_ and corpus_mapper_.
+  bool namespace_id_fingerprint_;
+
   // A log used to store all documents, it serves as a ground truth of doc
   // store. key_mapper_ and document_id_mapper_ can be regenerated from it.
   std::unique_ptr<PortableFileBackedProtoLog<DocumentWrapper>> document_log_;
@@ -733,6 +745,13 @@ class DocumentStore {
   libtextclassifier3::StatusOr<
       google::protobuf::RepeatedPtrField<DocumentDebugInfoProto::CorpusInfo>>
   CollectCorpusInfo() const;
+
+  // Build fingerprint for the keys of document_key_mapper_ and corpus_mapper_.
+  // Note that namespace_id_fingerprint_ controls the way that a fingerprint is
+  // built.
+  std::string MakeFingerprint(NamespaceId namespace_id,
+                              std::string_view namespace_,
+                              std::string_view uri_or_schema) const;
 };
 
 }  // namespace lib