Add support for wrapping a LinkView in a Results

src/impl/results_notifier.cpp

@@ -28,6 +28,7 @@ ResultsNotifier::ResultsNotifier(Results& target)
 : BackgroundCollection(target.get_realm())
 , m_target_results(&target)
 , m_sort(target.get_sort())
+, m_from_linkview(target.get_linkview().get() != nullptr)
 {
     Query q = target.get_query();
     set_table(*q.get_table());

src/impl/results_notifier.hpp

@@ -41,6 +41,7 @@ private:
     Results* m_target_results;
 
     const SortOrder m_sort;
+    bool m_from_linkview;
 
     // The source Query, in handover form iff m_sg is null
     std::unique_ptr<SharedGroup::Handover<Query>> m_query_handover;

src/list.cpp

@@ -155,7 +155,14 @@ void List::delete_all()
 
 Results List::sort(SortOrder order)
 {
-    return Results(m_realm, *m_object_schema, get_query(), std::move(order));
+    verify_attached();
+    return Results(m_realm, *m_object_schema, m_link_view, util::none, std::move(order));
+}
+
+Results List::filter(Query q)
+{
+    verify_attached();
+    return Results(m_realm, *m_object_schema, m_link_view, get_query().and_query(std::move(q)));
 }
 
 // These definitions rely on that LinkViews are interned by core

src/list.hpp

@@ -67,6 +67,7 @@ public:
     void delete_all();
 
     Results sort(SortOrder order);
+    Results filter(Query q);
 
     bool operator==(List const& rgt) const noexcept;
 

src/results.cpp

@@ -57,6 +57,21 @@ Results::Results(SharedRealm r, const ObjectSchema &o, Table& table)
 {
 }
 
+Results::Results(SharedRealm r, const ObjectSchema& o, LinkViewRef lv, util::Optional<Query> q, SortOrder s)
+: m_realm(std::move(r))
+, m_object_schema(&o)
+, m_link_view(lv)
+, m_table(&lv->get_target_table())
+, m_sort(std::move(s))
+, m_mode(Mode::LinkView)
+{
+    REALM_ASSERT(m_sort.column_indices.size() == m_sort.ascending.size());
+    if (q) {
+        m_query = std::move(*q);
+        m_mode = Mode::Query;
+    }
+}
+
 Results::~Results()
 {
     if (m_notifier) {
@@ -72,6 +87,8 @@ void Results::validate_read() const
         throw InvalidatedException();
     if (m_mode == Mode::TableView && !m_table_view.is_attached())
         throw InvalidatedException();
+    if (m_mode == Mode::LinkView && !m_link_view->is_attached())
+        throw InvalidatedException();
 }
 
 void Results::validate_write() const
@@ -99,6 +116,7 @@ size_t Results::size()
         case Mode::Empty:    return 0;
         case Mode::Table:    return m_table->size();
         case Mode::Query:    return m_query.count();
+        case Mode::LinkView: return m_link_view->size();
         case Mode::TableView:
             update_tableview();
             return m_table_view.size();
@@ -120,12 +138,21 @@ RowExpr Results::get(size_t row_ndx)
             if (row_ndx < m_table->size())
                 return m_table->get(row_ndx);
             break;
+        case Mode::LinkView:
+            if (update_linkview()) {
+               if (row_ndx < m_link_view->size())
+                   return m_link_view->get(row_ndx);
+                break;
+            }
+            REALM_FALLTHROUGH;
         case Mode::Query:
         case Mode::TableView:
             update_tableview();
-            if (row_ndx < m_table_view.size())
+            if (row_ndx >= m_table_view.size())
-                return (!m_live && !m_table_view.is_row_attached(row_ndx)) ? RowExpr() : m_table_view.get(row_ndx);
                 break;
+            if (!m_live && !m_table_view.is_row_attached(row_ndx))
+                return {};
+            return m_table_view.get(row_ndx);
     }
 
     throw OutOfBoundsIndexException{row_ndx, size()};
@@ -139,6 +166,10 @@ util::Optional<RowExpr> Results::first()
             return none;
         case Mode::Table:
             return m_table->size() == 0 ? util::none : util::make_optional(m_table->front());
+        case Mode::LinkView:
+            if (update_linkview())
+                return m_link_view->size() == 0 ? util::none : util::make_optional(m_link_view->get(0));
+            REALM_FALLTHROUGH;
         case Mode::Query:
         case Mode::TableView:
             update_tableview();
@@ -155,6 +186,10 @@ util::Optional<RowExpr> Results::last()
             return none;
         case Mode::Table:
             return m_table->size() == 0 ? util::none : util::make_optional(m_table->back());
+        case Mode::LinkView:
+            if (update_linkview())
+                return m_link_view->size() == 0 ? util::none : util::make_optional(m_link_view->get(m_link_view->size() - 1));
+            REALM_FALLTHROUGH;
         case Mode::Query:
         case Mode::TableView:
             update_tableview();
@@ -163,12 +198,24 @@ util::Optional<RowExpr> Results::last()
     REALM_UNREACHABLE();
 }
 
+bool Results::update_linkview()
+{
+    if (m_sort) {
+        m_query = get_query();
+        m_mode = Mode::Query;
+        update_tableview();
+        return false;
+    }
+    return true;
+}
+
 void Results::update_tableview()
 {
     validate_read();
     switch (m_mode) {
         case Mode::Empty:
         case Mode::Table:
+        case Mode::LinkView:
             return;
         case Mode::Query:
             m_table_view = m_query.find_all();
@@ -214,6 +261,10 @@ size_t Results::index_of(size_t row_ndx)
             return not_found;
         case Mode::Table:
             return row_ndx;
+        case Mode::LinkView:
+            if (update_linkview())
+                return m_link_view->find(row_ndx);
+            REALM_FALLTHROUGH;
         case Mode::Query:
         case Mode::TableView:
             update_tableview();
@@ -241,6 +292,10 @@ util::Optional<Mixed> Results::aggregate(size_t column, bool return_none_for_emp
                 if (return_none_for_empty && m_table->size() == 0)
                     return none;
                 return util::Optional<Mixed>(getter(*m_table));
+            case Mode::LinkView:
+                m_query = get_query();
+                m_mode = Mode::Query;
+                REALM_FALLTHROUGH;
             case Mode::Query:
             case Mode::TableView:
                 this->update_tableview();
@@ -315,6 +370,10 @@ void Results::clear()
             update_tableview();
             m_table_view.clear(RemoveMode::unordered);
             break;
+        case Mode::LinkView:
+            validate_write();
+            m_link_view->remove_all_target_rows();
+            break;
     }
 }
 
@@ -327,6 +386,8 @@ Query Results::get_query() const
             return m_query;
         case Mode::TableView:
             return m_table_view.get_query();
+        case Mode::LinkView:
+            return m_table->where(m_link_view);
         case Mode::Table:
             return m_table->where();
     }
@@ -339,6 +400,10 @@ TableView Results::get_tableview()
     switch (m_mode) {
         case Mode::Empty:
             return {};
+        case Mode::LinkView:
+            if (update_linkview())
+                return m_table->where(m_link_view).find_all();
+            REALM_FALLTHROUGH;
         case Mode::Query:
         case Mode::TableView:
             update_tableview();
@@ -352,12 +417,16 @@ TableView Results::get_tableview()
 Results Results::sort(realm::SortOrder&& sort) const
 {
     REALM_ASSERT(sort.column_indices.size() == sort.ascending.size());
-    return Results(m_realm, get_object_schema(), get_query(), std::move(sort));
+    if (m_link_view)
+        return Results(m_realm, *m_object_schema, m_link_view, m_query, std::move(sort));
+    return Results(m_realm, *m_object_schema, get_query(), std::move(sort));
 }
 
 Results Results::filter(Query&& q) const
 {
-    return Results(m_realm, get_object_schema(), get_query().and_query(std::move(q)), get_sort());
+    if (m_link_view)
+        return Results(m_realm, *m_object_schema, m_link_view, get_query().and_query(std::move(q)), m_sort);
+    return Results(m_realm, *m_object_schema, get_query().and_query(std::move(q)), m_sort);
 }
 
 void Results::prepare_async()

src/results.hpp

@@ -53,6 +53,7 @@ public:
     Results() = default;
     Results(SharedRealm r, const ObjectSchema& o, Table& table);
     Results(SharedRealm r, const ObjectSchema& o, Query q, SortOrder s = {});
+    Results(SharedRealm r, const ObjectSchema& o, LinkViewRef lv, util::Optional<Query> q = {}, SortOrder s = {});
     ~Results();
 
     // Results is copyable and moveable
@@ -80,6 +81,9 @@ public:
     // Get the object type which will be returned by get()
     StringData get_object_type() const noexcept;
 
+    // Get the LinkView this Results is derived from, if any
+    LinkViewRef get_linkview() const { return m_link_view; }
+
     // Set whether the TableView should sync if needed before accessing results
     void set_live(bool live);
 
@@ -125,6 +129,7 @@ public:
         Empty, // Backed by nothing (for missing tables)
         Table, // Backed directly by a Table
         Query, // Backed by a query that has not yet been turned into a TableView
+        LinkView, // Backed directly by a LinkView
         TableView // Backed by a TableView created from a Query
     };
     // Get the currrent mode of the Results
@@ -171,8 +176,6 @@ public:
         UnsupportedColumnTypeException(size_t column, const Table* table);
     };
 
-    void update_tableview();
-
     // Create an async query from this Results
     // The query will be run on a background thread and delivered to the callback,
     // and then rerun after each commit (if needed) and redelivered if it changed
@@ -193,6 +196,7 @@ private:
     const ObjectSchema *m_object_schema;
     Query m_query;
     TableView m_table_view;
+    LinkViewRef m_link_view;
     Table* m_table = nullptr;
     SortOrder m_sort;
     bool m_live = true;
@@ -203,6 +207,9 @@ private:
     bool m_has_used_table_view = false;
     bool m_wants_background_updates = true;
 
+    void update_tableview();
+    bool update_linkview();
+
     void validate_read() const;
     void validate_write() const;
 

tests/list.cpp

@@ -5,8 +5,9 @@
 
 #include "binding_context.hpp"
 #include "list.hpp"
-#include "property.hpp"
 #include "object_schema.hpp"
+#include "property.hpp"
+#include "results.hpp"
 #include "schema.hpp"
 
 #include "impl/realm_coordinator.hpp"
@@ -219,4 +220,33 @@ TEST_CASE("list") {
             }
         }
     }
+
+    SECTION("sort()") {
+        auto objectschema = &*r->config().schema->find("origin");
+        List list(r, *objectschema, lv);
+        auto results = list.sort({{0}, {false}});
+
+        REQUIRE(&results.get_object_schema() == objectschema);
+        REQUIRE(results.get_mode() == Results::Mode::LinkView);
+        REQUIRE(results.size() == 10);
+        REQUIRE(results.sum(0) == 45);
+
+        for (size_t i = 0; i < 10; ++i) {
+            REQUIRE(results.get(i).get_index() == 9 - i);
+        }
+    }
+
+    SECTION("filter()") {
+        auto objectschema = &*r->config().schema->find("origin");
+        List list(r, *objectschema, lv);
+        auto results = list.filter(target->where().greater(0, 5));
+
+        REQUIRE(&results.get_object_schema() == objectschema);
+        REQUIRE(results.get_mode() == Results::Mode::Query);
+        REQUIRE(results.size() == 4);
+
+        for (size_t i = 0; i < 4; ++i) {
+            REQUIRE(results.get(i).get_index() == i + 6);
+        }
+    }
 }