1 files changed, 26 insertions, 27 deletions

diff --git a/icing/index/hit/doc-hit-info.h b/icing/index/hit/doc-hit-info.h
index 0be87d6..2770de2 100644
--- a/icing/index/hit/doc-hit-info.h
+++ b/icing/index/hit/doc-hit-info.h
@@ -26,19 +26,15 @@ namespace icing {
 namespace lib {
 
 // DocHitInfo provides a collapsed view of all hits for a specific doc.
-// Hits contain a document_id, section_id and a term frequency. The
-// information in multiple hits is collapse into a DocHitInfo by providing a
-// SectionIdMask of all sections that contained a hit for this term as well as
-// the highest term frequency of any hit for each section.
+// Hits contain a document_id and section_id. The information in multiple hits
+// is collapse into a DocHitInfo by providing a SectionIdMask of all sections
+// that contained a hit for this term.
 class DocHitInfo {
  public:
   explicit DocHitInfo(DocumentId document_id_in = kInvalidDocumentId,
                       SectionIdMask hit_section_ids_mask = kSectionIdMaskNone)
       : document_id_(document_id_in),
-        hit_section_ids_mask_(hit_section_ids_mask) {
-    memset(hit_term_frequency_, Hit::kNoTermFrequency,
-           sizeof(hit_term_frequency_));
-  }
+        hit_section_ids_mask_(hit_section_ids_mask) {}
 
   DocumentId document_id() const { return document_id_; }
 
@@ -50,41 +46,44 @@ class DocHitInfo {
     hit_section_ids_mask_ = section_id_mask;
   }
 
-  Hit::TermFrequency hit_term_frequency(SectionId section_id) const {
-    return hit_term_frequency_[section_id];
+  bool operator<(const DocHitInfo& other) const {
+    if (document_id() != other.document_id()) {
+      // Sort by document_id descending. This mirrors how the individual hits
+      // that are collapsed into this DocHitInfo would sort with other hits -
+      // document_ids are inverted when encoded in hits. Hits are encoded this
+      // way because they are appended to posting lists and the most recent
+      // value appended to a posting list must have the smallest encoded value
+      // of any hit on the posting list.
+      return document_id() > other.document_id();
+    }
+    return hit_section_ids_mask() < other.hit_section_ids_mask();
   }
-
-  bool operator<(const DocHitInfo& other) const;
   bool operator==(const DocHitInfo& other) const {
-    return (*this < other) == (other < *this);
+    return document_id_ == other.document_id_ &&
+           hit_section_ids_mask_ == other.hit_section_ids_mask_;
   }
 
-  // Updates the hit_section_ids_mask and hit_term_frequency for the
-  // section, if necessary.
-  void UpdateSection(SectionId section_id,
-                     Hit::TermFrequency hit_term_frequency);
+  // Updates the hit_section_ids_mask for the section, if necessary.
+  void UpdateSection(SectionId section_id) {
+    hit_section_ids_mask_ |= (UINT64_C(1) << section_id);
+  }
 
-  // Merges the sections of other into this. The hit_section_ids_masks are or'd;
-  // if this.hit_term_frequency_[sectionId] has already been defined,
-  // other.hit_term_frequency_[sectionId] value is ignored.
+  // Merges the sections of other into this. The hit_section_ids_masks are or'd.
   //
   // This does not affect the DocumentId of this or other. If callers care about
   // only merging sections for DocHitInfos with the same DocumentId, callers
   // should check this themselves.
-  void MergeSectionsFrom(const DocHitInfo& other);
+  void MergeSectionsFrom(const SectionIdMask& other_hit_section_ids_mask) {
+    hit_section_ids_mask_ |= other_hit_section_ids_mask;
+  }
 
  private:
   DocumentId document_id_;
   SectionIdMask hit_section_ids_mask_;
-  Hit::TermFrequency hit_term_frequency_[kMaxSectionId + 1];
 } __attribute__((packed));
-static_assert(sizeof(DocHitInfo) == 22, "");
+static_assert(sizeof(DocHitInfo) == 12, "");
 // TODO(b/138991332) decide how to remove/replace all is_packed_pod assertions.
 static_assert(icing_is_packed_pod<DocHitInfo>::value, "go/icing-ubsan");
-static_assert(
-    sizeof(Hit::TermFrequency) == 1,
-    "Change how hit_term_frequency_ is initialized if changing the type "
-    "of Hit::TermFrequency");
 
 }  // namespace lib
 }  // namespace icing