Adjust signature for IDocsumStoreDocument::get_field_value() to return DocsumStoreFieldValue.

7 files changed, 52 insertions, 19 deletions

diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.cpp b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.cpp
index e6c8d0b6ab8..71800eb2128 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.cpp
@@ -16,7 +16,7 @@ DocsumStoreDocument::DocsumStoreDocument(std::unique_ptr<document::Document> doc
 
 DocsumStoreDocument::~DocsumStoreDocument() = default;
 
-std::unique_ptr<document::FieldValue>
+DocsumStoreFieldValue
 DocsumStoreDocument::get_field_value(const vespalib::string& field_name) const
 {
     if (_document) {
@@ -24,11 +24,11 @@ DocsumStoreDocument::get_field_value(const vespalib::string& field_name) const
         auto value(field.getDataType().createFieldValue());
         if (value) {
             if (_document->getValue(field, *value)) {
-                return value;
+                return DocsumStoreFieldValue(std::move(value));
             }
         }
     }
-    return {};
+    return DocsumStoreFieldValue();
 }
 
 void
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.h b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.h
index 3b0bea6e721..26cccc9970f 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_document.h
@@ -17,7 +17,7 @@ class DocsumStoreDocument : public IDocsumStoreDocument
 public:
     DocsumStoreDocument(std::unique_ptr<document::Document> document);
     ~DocsumStoreDocument() override;
-    std::unique_ptr<document::FieldValue> get_field_value(const vespalib::string& field_name) const override;
+    DocsumStoreFieldValue get_field_value(const vespalib::string& field_name) const override;
     void insert_summary_field(const vespalib::string& field_name, vespalib::slime::Inserter& inserter) const override;
     void insert_document_id(vespalib::slime::Inserter& inserter) const override;
 };
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_field_value.h b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_field_value.h
new file mode 100644
index 00000000000..d06a2ab8287
--- /dev/null
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsum_store_field_value.h
@@ -0,0 +1,38 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include <vespa/document/fieldvalue/fieldvalue.h>
+#include <memory>
+
+namespace search::docsummary {
+
+/*
+ * Class containing a field value returned from an IDocsumStoreDocument.
+ */
+class DocsumStoreFieldValue {
+    const document::FieldValue*           _value;
+    std::unique_ptr<document::FieldValue> _value_store;
+public:
+    explicit DocsumStoreFieldValue(std::unique_ptr<document::FieldValue> value) noexcept
+        : _value(value.get()),
+          _value_store(std::move(value))
+    {
+    }
+    explicit DocsumStoreFieldValue(const document::FieldValue* value) noexcept
+        : _value(value),
+          _value_store()
+    {
+    }
+    DocsumStoreFieldValue()
+        : DocsumStoreFieldValue(nullptr)
+    {
+    }
+    ~DocsumStoreFieldValue() = default;
+    const document::FieldValue& operator*() const noexcept  { return *_value; }
+    const document::FieldValue* operator->() const noexcept { return _value; }
+    const document::FieldValue* get() const noexcept        { return _value; }
+    operator bool () const noexcept { return _value != nullptr; }
+};
+
+}
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/general_result.cpp b/searchsummary/src/vespa/searchsummary/docsummary/general_result.cpp
index 825c3b39c1b..359959391fd 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/general_result.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/general_result.cpp
@@ -62,13 +62,13 @@ GeneralResult::GetPresentEntryFromEnumValue(uint32_t value)
     return GetPresentEntry(idx);
 }
 
-std::unique_ptr<document::FieldValue>
+DocsumStoreFieldValue
 GeneralResult::get_field_value(const vespalib::string& field_name) const
 {
     if (_document != nullptr) {
         return _document->get_field_value(field_name);
     }
-    return {};
+    return DocsumStoreFieldValue();
 }
 
 bool
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/general_result.h b/searchsummary/src/vespa/searchsummary/docsummary/general_result.h
index cff27a496e3..8f7a1377502 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/general_result.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/general_result.h
@@ -4,10 +4,7 @@
 
 #include "resultclass.h"
 #include "docsumstorevalue.h"
-
-namespace document {
-class FieldValue;
-}
+#include "docsum_store_field_value.h"
 
 namespace search::docsummary {
 
@@ -42,7 +39,7 @@ public:
     }
     ResEntry *GetPresentEntry(const char *name);
     ResEntry *GetPresentEntryFromEnumValue(uint32_t val);
-    std::unique_ptr<document::FieldValue> get_field_value(const vespalib::string& field_name) const;
+    DocsumStoreFieldValue get_field_value(const vespalib::string& field_name) const;
     bool unpack(const char *buf, const size_t buflen);
 
     bool inplaceUnpack(const DocsumStoreValue &value) {
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/i_docsum_store_document.h b/searchsummary/src/vespa/searchsummary/docsummary/i_docsum_store_document.h
index c177568c467..b9c2ae76e7a 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/i_docsum_store_document.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/i_docsum_store_document.h
@@ -2,10 +2,8 @@
 
 #pragma once
 
+#include "docsum_store_field_value.h"
 #include <vespa/vespalib/stllike/string.h>
-#include <memory>
-
-namespace document { class FieldValue; }
 
 namespace vespalib::slime { struct Inserter; }
 
@@ -20,7 +18,7 @@ class IDocsumStoreDocument
 {
 public:
     virtual ~IDocsumStoreDocument() = default;
-    virtual std::unique_ptr<document::FieldValue> get_field_value(const vespalib::string& field_name) const = 0;
+    virtual DocsumStoreFieldValue get_field_value(const vespalib::string& field_name) const = 0;
     virtual void insert_summary_field(const vespalib::string& field_name, vespalib::slime::Inserter& inserter) const = 0;
     virtual void insert_document_id(vespalib::slime::Inserter& inserter) const = 0;
 };
diff --git a/streamingvisitors/src/vespa/vsm/vsm/docsumfilter.cpp b/streamingvisitors/src/vespa/vsm/vsm/docsumfilter.cpp
index 5bcead79f97..3d0f8ed6e37 100644
--- a/streamingvisitors/src/vespa/vsm/vsm/docsumfilter.cpp
+++ b/streamingvisitors/src/vespa/vsm/vsm/docsumfilter.cpp
@@ -133,7 +133,7 @@ class DocsumStoreVsmDocument : public IDocsumStoreDocument
 public:
     DocsumStoreVsmDocument(const document::Document* document);
     ~DocsumStoreVsmDocument() override;
-    std::unique_ptr<document::FieldValue> get_field_value(const vespalib::string& field_name) const override;
+    DocsumStoreFieldValue get_field_value(const vespalib::string& field_name) const override;
     void insert_summary_field(const vespalib::string& field_name, vespalib::slime::Inserter& inserter) const override;
     void insert_document_id(vespalib::slime::Inserter& inserter) const override;
 };
@@ -145,7 +145,7 @@ DocsumStoreVsmDocument::DocsumStoreVsmDocument(const document::Document* documen
 
 DocsumStoreVsmDocument::~DocsumStoreVsmDocument() = default;
 
-std::unique_ptr<document::FieldValue>
+DocsumStoreFieldValue
 DocsumStoreVsmDocument::get_field_value(const vespalib::string& field_name) const
 {
     if (_document != nullptr) {
@@ -153,11 +153,11 @@ DocsumStoreVsmDocument::get_field_value(const vespalib::string& field_name) cons
         auto value(field.getDataType().createFieldValue());
         if (value) {
             if (_document->getValue(field, *value)) {
-                return value;
+                return DocsumStoreFieldValue(std::move(value));
             }
         }
     }
-    return {};
+    return DocsumStoreFieldValue();
 }
 
 void