added low-level code used to identify matching elements

3 files changed, 45 insertions, 0 deletions

diff --git a/searchlib/src/tests/queryeval/same_element/same_element_test.cpp b/searchlib/src/tests/queryeval/same_element/same_element_test.cpp
index 6ec379140c0..c24a11833e7 100644
--- a/searchlib/src/tests/queryeval/same_element/same_element_test.cpp
+++ b/searchlib/src/tests/queryeval/same_element/same_element_test.cpp
@@ -14,6 +14,13 @@ using namespace search::fef;
 using namespace search::queryeval;
 using search::attribute::ElementIterator;
 
+void verify_elements(SameElementSearch &se, uint32_t docid, const std::initializer_list<uint32_t> list) {
+    std::vector<uint32_t> expect(list);
+    std::vector<uint32_t> actual;
+    se.find_matching_elements(docid, actual);
+    EXPECT_EQUAL(actual, expect);
+}
+
 std::unique_ptr<SameElementBlueprint> make_blueprint(const std::vector<FakeResult> &children, bool fake_attr = false) {
     auto result = std::make_unique<SameElementBlueprint>(false);
     for (size_t i = 0; i < children.size(); ++i) {
@@ -61,6 +68,20 @@ TEST("require that simple match can be found") {
     EXPECT_EQUAL(result, expect);
 }
 
+TEST("require that matching elements can be identified") {
+    auto a = make_result({{5, {1,3,7,12}}, {10, {1,2,3}}});
+    auto b = make_result({{5, {3,5,7,10}}, {10, {4,5,6}}});
+    auto bp = finalize(make_blueprint({a,b}), false);
+    auto md = MatchData::makeTestInstance(0, 0);
+    auto search = bp->createSearch(*md, false);
+    search->initRange(1, 1000);
+    SameElementSearch *se = dynamic_cast<SameElementSearch*>(search.get());
+    ASSERT_TRUE(se != nullptr);
+    TEST_DO(verify_elements(*se, 5, {3, 7}));
+    TEST_DO(verify_elements(*se, 10, {}));
+    TEST_DO(verify_elements(*se, 20, {}));
+}
+
 TEST("require that children must match within same element") {
     auto a = make_result({{5, {1,3,7}}});
     auto b = make_result({{5, {2,5,10}}});
diff --git a/searchlib/src/vespa/searchlib/queryeval/same_element_search.cpp b/searchlib/src/vespa/searchlib/queryeval/same_element_search.cpp
index 8f3fc9c350d..37f8eccadd9 100644
--- a/searchlib/src/vespa/searchlib/queryeval/same_element_search.cpp
+++ b/searchlib/src/vespa/searchlib/queryeval/same_element_search.cpp
@@ -114,4 +114,22 @@ SameElementSearch::visitMembers(vespalib::ObjectVisitor &visitor) const
     visit(visitor, "strict", _strict);
 }
 
+void
+SameElementSearch::find_matching_elements(uint32_t docid, std::vector<uint32_t> &dst)
+{
+    if (check_docid_match(docid)) {
+        unpack_children(docid);
+        int32_t cand = 0;
+        while (cand >= 0) {
+            int32_t next = try_match(_childMatch, _iterators, cand);
+            if (next == cand) {
+                dst.push_back(cand);
+                ++cand;
+            } else {
+                cand = next;
+            }
+        }
+    }
+}
+
 }
diff --git a/searchlib/src/vespa/searchlib/queryeval/same_element_search.h b/searchlib/src/vespa/searchlib/queryeval/same_element_search.h
index 1fd381eb1ae..ae7ecab781d 100644
--- a/searchlib/src/vespa/searchlib/queryeval/same_element_search.h
+++ b/searchlib/src/vespa/searchlib/queryeval/same_element_search.h
@@ -6,6 +6,7 @@
 #include <vespa/searchlib/fef/matchdata.h>
 #include <vespa/searchlib/fef/termfieldmatchdataarray.h>
 #include <vespa/searchlib/fef/termfieldmatchdata.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <memory>
 #include <vector>
 
@@ -40,6 +41,11 @@ public:
     void doUnpack(uint32_t) override {}
     void visitMembers(vespalib::ObjectVisitor &visitor) const override;
     const std::vector<SearchIterator::UP> &children() const { return _children; }
+
+    // used during docsum fetching to identify matching elements
+    // initRange must be called before use.
+    // doSeek/doUnpack must not be called.
+    void find_matching_elements(uint32_t docid, std::vector<uint32_t> &dst);
 };
 
 }