Add ReadableAttributeVector accessor to IAttributeManager

Provides a unified interface for fetching both regular as well as
imported attributes. Exposing `ReadableAttributeVector` instead of
raw `AttributeVector` instances enforces that all access is done via
appropriate acquired read guards.

Refactor document selection processing code to use the new interface
in order to prepare for imported field support in selections.

2 files changed, 13 insertions, 0 deletions

diff --git a/searchlib/src/tests/attribute/searchable/attribute_searchable_adapter_test.cpp b/searchlib/src/tests/attribute/searchable/attribute_searchable_adapter_test.cpp
index 4818287b429..2eafeab20bd 100644
--- a/searchlib/src/tests/attribute/searchable/attribute_searchable_adapter_test.cpp
+++ b/searchlib/src/tests/attribute/searchable/attribute_searchable_adapter_test.cpp
@@ -123,6 +123,15 @@ public:
         return IAttributeContext::UP();
     }
 
+    std::shared_ptr<attribute::ReadableAttributeVector> readable_attribute_vector(const string& name) const override {
+        if (name == field) {
+            return _attribute_vector;
+        } else if (name == other) {
+            return _other;
+        }
+        return {};
+    }
+
     void asyncForAttribute(const vespalib::string &name, std::unique_ptr<IAttributeFunctor> func) const override;
 };
 
diff --git a/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp b/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
index e9addae07b9..24be21f65ec 100644
--- a/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
+++ b/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
@@ -100,6 +100,10 @@ public:
     void asyncForAttribute(const vespalib::string &, std::unique_ptr<IAttributeFunctor>) const override {
         assert(!"Not implemented");
     }
+
+    std::shared_ptr<attribute::ReadableAttributeVector> readable_attribute_vector(const string&) const override {
+        return _attribute_vector;
+    }
 };
 
 constexpr uint32_t DOCID_LIMIT = 3;