Add noexcept, nodiscard and some constexpr

4 files changed, 27 insertions, 28 deletions

diff --git a/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp b/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
index 99107749610..90bcaabc7a5 100644
--- a/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
+++ b/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
@@ -35,8 +35,8 @@ DiskIndex::LookupResult::LookupResult() noexcept
 {
 }
 
-DiskIndex::Key::Key() = default;
-DiskIndex::Key::Key(IndexList indexes, vespalib::stringref word) :
+DiskIndex::Key::Key() noexcept = default;
+DiskIndex::Key::Key(IndexList indexes, vespalib::stringref word) noexcept :
     _word(word),
     _indexes(std::move(indexes))
 {
@@ -302,7 +302,7 @@ DiskIndex::readPostingList(const LookupResult &lookupRes) const
     SchemaUtil::IndexIterator it(_schema, lookupRes.indexId);
     handle->_file = _postingFiles[it.getIndex()].get();
     if (handle->_file == nullptr) {
-        return PostingListHandle::UP();
+        return {};
     }
     const uint32_t firstSegment = 0;
     const uint32_t numSegments = 0; // means all segments
@@ -316,7 +316,7 @@ DiskIndex::readBitVector(const LookupResult &lookupRes) const
     SchemaUtil::IndexIterator it(_schema, lookupRes.indexId);
     BitVectorDictionary * dict = _bitVectorDicts[it.getIndex()].get();
     if (dict == nullptr) {
-        return BitVector::UP();
+        return {};
     }
     return dict->lookup(lookupRes.wordNum);
 }
@@ -330,7 +330,7 @@ DiskIndex::calculateSize()
 
 namespace {
 
-DiskIndex::LookupResult _G_nothing;
+DiskIndex::LookupResult G_nothing;
 
 class LookupCache {
 public:
@@ -352,7 +352,7 @@ public:
                 return result;
             }
         }
-        return _G_nothing;
+        return G_nothing;
     }
 private:
 
diff --git a/searchlib/src/vespa/searchlib/diskindex/diskindex.h b/searchlib/src/vespa/searchlib/diskindex/diskindex.h
index faa562e5809..9672939a741 100644
--- a/searchlib/src/vespa/searchlib/diskindex/diskindex.h
+++ b/searchlib/src/vespa/searchlib/diskindex/diskindex.h
@@ -32,8 +32,8 @@ public:
         uint64_t                         bitOffset;
         using UP = std::unique_ptr<LookupResult>;
         LookupResult() noexcept;
-        bool valid() const { return counts._numDocs > 0; }
-        void swap(LookupResult & rhs) {
+        bool valid() const noexcept { return counts._numDocs > 0; }
+        void swap(LookupResult & rhs) noexcept {
             std::swap(indexId , rhs.indexId);
             std::swap(wordNum , rhs.wordNum);
             counts.swap(rhs.counts);
@@ -45,22 +45,22 @@ public:
 
     class Key {
     public:
-        Key();
-        Key(IndexList indexes, vespalib::stringref word);
+        Key() noexcept;
+        Key(IndexList indexes, vespalib::stringref word) noexcept;
         Key(const Key &);
         Key & operator = (const Key &);
-        Key(Key &&) = default;
-        Key & operator = (Key &&) = default;
+        Key(Key &&) noexcept = default;
+        Key & operator = (Key &&) noexcept = default;
         ~Key();
-        uint32_t hash() const {
+        uint32_t hash() const noexcept {
             return vespalib::hashValue(_word.c_str(), _word.size());
         }
-        bool operator == (const Key & rhs) const {
+        bool operator == (const Key & rhs) const noexcept {
             return _word == rhs._word;
         }
         void push_back(uint32_t indexId) { _indexes.push_back(indexId); }
-        const IndexList & getIndexes() const { return _indexes; }
-        const vespalib::string & getWord() const { return _word; }
+        const IndexList & getIndexes() const noexcept { return _indexes; }
+        const vespalib::string & getWord() const noexcept { return _word; }
     private:
         vespalib::string _word;
         IndexList        _indexes;
diff --git a/searchlib/src/vespa/searchlib/index/field_length_info.h b/searchlib/src/vespa/searchlib/index/field_length_info.h
index d1fba4bc6d2..03125e99a87 100644
--- a/searchlib/src/vespa/searchlib/index/field_length_info.h
+++ b/searchlib/src/vespa/searchlib/index/field_length_info.h
@@ -15,19 +15,19 @@ private:
     uint32_t _num_samples;
 
 public:
-    FieldLengthInfo()
+    FieldLengthInfo() noexcept
         : FieldLengthInfo(0.0, 0)
     {
     }
 
-    FieldLengthInfo(double average_field_length, uint32_t num_samples)
+    FieldLengthInfo(double average_field_length, uint32_t num_samples) noexcept
         : _average_field_length(average_field_length),
           _num_samples(num_samples)
     {
     }
 
-    double get_average_field_length() const { return _average_field_length; }
-    uint32_t get_num_samples() const { return _num_samples; }
+    [[nodiscard]] double get_average_field_length() const noexcept { return _average_field_length; }
+    [[nodiscard]] uint32_t get_num_samples() const noexcept { return _num_samples; }
 };
 
 }
diff --git a/searchlib/src/vespa/searchlib/index/postinglistcounts.h b/searchlib/src/vespa/searchlib/index/postinglistcounts.h
index 3d76e8203cb..1e58b2f5ef7 100644
--- a/searchlib/src/vespa/searchlib/index/postinglistcounts.h
+++ b/searchlib/src/vespa/searchlib/index/postinglistcounts.h
@@ -29,15 +29,14 @@ public:
         uint32_t _numDocs;   // Number of documents in segment
         uint32_t _lastDoc;   // Last document id in segment
 
-        Segment()
+        Segment() noexcept
             : _bitLength(0),
               _numDocs(0),
               _lastDoc(0)
         { }
 
         bool
-        operator==(const Segment &rhs) const
-        {
+        operator==(const Segment &rhs) const noexcept {
             return (_bitLength == rhs._bitLength &&
                     _numDocs == rhs._numDocs &&
                     _lastDoc == rhs._lastDoc);
@@ -59,24 +58,24 @@ public:
      */
     std::vector<Segment> _segments;
 
-    PostingListCounts()
+    PostingListCounts() noexcept
         : _numDocs(0),
           _bitLength(0),
           _segments()
     { }
-    void swap(PostingListCounts & rhs) {
+    void swap(PostingListCounts & rhs) noexcept {
         std::swap(_numDocs, rhs._numDocs);
         std::swap(_bitLength, rhs._bitLength);
         std::swap(_segments, rhs._segments);
     }
 
-    void clear() {
+    void clear() noexcept {
         _bitLength = 0;
         _numDocs = 0;
         _segments.clear();
     }
 
-    bool operator==(const PostingListCounts &rhs) const {
+    bool operator==(const PostingListCounts &rhs) const noexcept {
         return (_numDocs == rhs._numDocs &&
                 _bitLength == rhs._bitLength &&
                 _segments == rhs._segments);
@@ -92,7 +91,7 @@ public:
     uint64_t _accNumDocs;   // Used by prefix search for now.
     PostingListCounts _counts;
 
-    PostingListOffsetAndCounts()
+    PostingListOffsetAndCounts() noexcept
         : _offset(0),
           _accNumDocs(0u),
           _counts()