Reduce code duplication by letting enum store comparators inherit unique store comparators.

4 files changed, 52 insertions, 36 deletions

diff --git a/vespalib/src/vespa/vespalib/datastore/entry_comparator.h b/vespalib/src/vespa/vespalib/datastore/entry_comparator.h
index a598ca195ae..09b850a4746 100644
--- a/vespalib/src/vespa/vespalib/datastore/entry_comparator.h
+++ b/vespalib/src/vespa/vespalib/datastore/entry_comparator.h
@@ -6,17 +6,19 @@
 
 namespace search::datastore {
 
-/*
- * Compare two entries based on entry refs.  Valid entry ref is mapped
- * to an entry in a data store.  Invalid entry ref is mapped to a
- * temporary entry owned or referenced by comparator instance.
+/**
+ * Less-than comparator for two entries based on entry refs.
+ *
+ * Valid entry ref is mapped to an entry in a data store.
+ * Invalid entry ref is mapped to a temporary entry owned or referenced by comparator instance.
  */
 class EntryComparator {
 public:
     virtual ~EntryComparator() {}
+
     /**
-     * Compare the values represented by the given unique store entry refs.
-     **/
+     * Returns true if the value represented by lhs ref is less than the value represented by rhs ref.
+     */
     virtual bool operator()(const EntryRef lhs, const EntryRef rhs) const = 0;
 };
 
diff --git a/vespalib/src/vespa/vespalib/datastore/unique_store.h b/vespalib/src/vespa/vespalib/datastore/unique_store.h
index b4ed3f6d86b..cbaa6aa7db0 100644
--- a/vespalib/src/vespa/vespalib/datastore/unique_store.h
+++ b/vespalib/src/vespa/vespalib/datastore/unique_store.h
@@ -61,6 +61,7 @@ public:
     Allocator& get_allocator() { return _allocator; }
     const Allocator& get_allocator() const { return _allocator; }
     IUniqueStoreDictionary& get_dictionary() { return *_dict; }
+    inline const DataStoreType& get_data_store() const { return _allocator.get_data_store(); }
 
     // Pass on hold list management to underlying store
     void transferHoldLists(generation_t generation);
diff --git a/vespalib/src/vespa/vespalib/datastore/unique_store_comparator.h b/vespalib/src/vespa/vespalib/datastore/unique_store_comparator.h
index acd4f531e2c..ae52791ae0f 100644
--- a/vespalib/src/vespa/vespalib/datastore/unique_store_comparator.h
+++ b/vespalib/src/vespa/vespalib/datastore/unique_store_comparator.h
@@ -9,7 +9,7 @@
 
 namespace search::datastore {
 
-/*
+/**
  * Helper class for comparing elements in unique store. 
  */
 template <typename EntryT>
@@ -20,7 +20,7 @@ public:
     }
 };
 
-/*
+/**
  * Helper class for comparing floating point elements in unique store with
  * special handling of NAN.
  */
@@ -39,7 +39,7 @@ public:
     }
 };
 
-/*
+/**
  * Specialized helper class for comparing float elements in unique store with
  * special handling of NAN.
  */
@@ -47,7 +47,7 @@ template <>
 class UniqueStoreComparatorHelper<float> : public UniqueStoreFloatingPointComparatorHelper<float> {
 };
 
-/*
+/**
  * Specialized helper class for comparing double elements in unique store with
  * special handling of NAN.
  */
@@ -55,35 +55,45 @@ template <>
 class UniqueStoreComparatorHelper<double> : public UniqueStoreFloatingPointComparatorHelper<double> {
 };
   
-/*
- * Compare two entries based on entry refs.  Valid entry ref is mapped
- * to an entry in a data store.  Invalid entry ref is mapped to a
- * temporary entry referenced by comparator instance.
+/**
+ * Compare two entries based on entry refs.
+ *
+ * Valid entry ref is mapped to an entry in a data store.
+ * Invalid entry ref is mapped to a temporary entry referenced by comparator instance.
  */
 template <typename EntryT, typename RefT>
 class UniqueStoreComparator : public EntryComparator {
+protected:
     using EntryType = EntryT;
     using WrappedEntryType = UniqueStoreEntry<EntryType>;
     using RefType = RefT;
     using DataStoreType = DataStoreT<RefT>;
     const DataStoreType &_store;
-    const EntryType &_value;
-public:
-    UniqueStoreComparator(const DataStoreType &store, const EntryType &value)
-        : _store(store),
-          _value(value)
-    {
-    }
+    const EntryType _fallback_value;
+
     inline const EntryType &get(EntryRef ref) const {
         if (ref.valid()) {
             RefType iRef(ref);
             return _store.template getEntry<WrappedEntryType>(iRef)->value();
         } else {
-            return _value;
+            return _fallback_value;
         }
     }
-    bool operator()(const EntryRef lhs, const EntryRef rhs) const override
+
+public:
+    UniqueStoreComparator(const DataStoreType &store, const EntryType &fallback_value)
+        : _store(store),
+          _fallback_value(fallback_value)
+    {
+    }
+
+    UniqueStoreComparator(const DataStoreType &store)
+        : _store(store),
+          _fallback_value()
     {
+    }
+
+    bool operator()(const EntryRef lhs, const EntryRef rhs) const override {
         const EntryType &lhsValue = get(lhs);
         const EntryType &rhsValue = get(rhs);
         return UniqueStoreComparatorHelper<EntryT>::less(lhsValue, rhsValue);
diff --git a/vespalib/src/vespa/vespalib/datastore/unique_store_string_comparator.h b/vespalib/src/vespa/vespalib/datastore/unique_store_string_comparator.h
index e5d3888a5e2..80e7a501cfa 100644
--- a/vespalib/src/vespa/vespalib/datastore/unique_store_string_comparator.h
+++ b/vespalib/src/vespa/vespalib/datastore/unique_store_string_comparator.h
@@ -7,24 +7,21 @@
 
 namespace search::datastore {
 
-/*
- * Compare two strings based on entry refs.  Valid entry ref is mapped
- * to a string in a data store.  Invalid entry ref is mapped to a
- * temporary string pointed to by comparator instance.
+/**
+ * Compare two strings based on entry refs.
+ *
+ * Valid entry ref is mapped to a string in a data store.
+ * Invalid entry ref is mapped to a temporary string pointed to by comparator instance.
  */
 template <typename RefT>
 class UniqueStoreStringComparator : public EntryComparator {
+protected:
     using RefType = RefT;
     using WrappedExternalEntryType = UniqueStoreEntry<std::string>;
     using DataStoreType = DataStoreT<RefT>;
     const DataStoreType &_store;
-    const char *_value;
-public:
-    UniqueStoreStringComparator(const DataStoreType &store, const char *value)
-        : _store(store),
-          _value(value)
-    {
-    }
+    const char *_fallback_value;
+
     const char *get(EntryRef ref) const {
         if (ref.valid()) {
             RefType iRef(ref);
@@ -36,12 +33,18 @@ public:
                 return _store.template getEntry<WrappedExternalEntryType>(iRef)->value().c_str();
             }
         } else {
-            return _value;
+            return _fallback_value;
         }
     }
 
-    bool operator()(const EntryRef lhs, const EntryRef rhs) const override
+public:
+    UniqueStoreStringComparator(const DataStoreType &store, const char *fallback_value)
+        : _store(store),
+          _fallback_value(fallback_value)
     {
+    }
+
+    bool operator()(const EntryRef lhs, const EntryRef rhs) const override {
         const char *lhs_value = get(lhs);
         const char *rhs_value = get(rhs);
         return (strcmp(lhs_value, rhs_value) < 0);