Add support for property queries.

README.md

@@ -120,6 +120,34 @@ final qt = box.query(Entity_.text.notNull())
   .build();
 ```
 
+### Property Queries
+
+Instead of returning complete entities, with property queries only values or an aggregate of a property can be returned.
+Build a regular query with conditions as seen above, then turn it into a property query, e.g.:
+
+```dart
+// final query ...
+
+// Use distinct or caseSensitive to refine results.
+final textQuery = query.stringProperty(Note_.text)
+    ..distinct = true
+    ..caseSensitive = true;
+final texts = textQuery.find();
+textQuery.close();
+
+// Get aggregates, like min, max, avg, sum and count.
+final createdQuery = query.integerProperty(Note_.created);
+final min = createdQuery.min();
+createdQuery.close();
+
+// Set replaceNullWith to map null values.
+final scoreQuery = query.doubleProperty(Note_.score);
+final scores = scoreQuery.find(replaceNullWith: 0.0);
+scoreQuery.close();
+
+query.close();
+```
+
 Help wanted
 -----------
 ObjectBox for Dart is still in an early stage with limited feature set (compared to other languages).

generator/lib/src/entity_resolver.dart

@@ -55,7 +55,6 @@ class EntityResolver extends Builder {
     // read all suitable annotated properties
     bool hasIdProperty = false;
     for (var f in element.fields) {
-
       if (_transientChecker.hasAnnotationOfExact(f)) {
         log.info("  skipping property ${f.name} (annotated with @Transient)");
         continue;

lib/src/bindings/bindings.dart

@@ -18,13 +18,13 @@ class _ObjectBoxBindings {
   obx_free_dart_t<OBX_bytes_array> obx_bytes_array_free;
   obx_free_dart_t<OBX_id_array> obx_id_array_free;
 
-  //  obx_free_dart_t<OBX__array> obx_string_array_free;
-  //  obx_free_dart_t<OBX__array> obx_int64_array_free;
-  //  obx_free_dart_t<OBX__array> obx_int32_array_free;
-  //  obx_free_dart_t<OBX__array> obx_int16_array_free;
-  //  obx_free_dart_t<OBX__array> obx_int8_array_free;
-  //  obx_free_dart_t<OBX__array> obx_double_array_free;
-  //  obx_free_dart_t<OBX__array> obx_float_array_free;
+  obx_free_dart_t<OBX_string_array> obx_string_array_free;
+  obx_free_dart_t<OBX_int64_array> obx_int64_array_free;
+  obx_free_dart_t<OBX_int32_array> obx_int32_array_free;
+  obx_free_dart_t<OBX_int16_array> obx_int16_array_free;
+  obx_free_dart_t<OBX_int8_array> obx_int8_array_free;
+  obx_free_dart_t<OBX_double_array> obx_double_array_free;
+  obx_free_dart_t<OBX_float_array> obx_float_array_free;
 
   // error info
   int Function() obx_last_error_code;
@@ -133,6 +133,27 @@ class _ObjectBoxBindings {
 
   obx_query_visit_dart_t obx_query_visit;
 
+  // query property
+  obx_query_prop_t<int> obx_query_prop;
+  obx_query_prop_close_t<int> obx_query_prop_close;
+
+  obx_query_prop_distinct_t<int, int> obx_query_prop_distinct;
+  obx_query_prop_distinct2_t<int, int> obx_query_prop_distinct_case;
+
+  obx_query_prop_op_t<int, Uint64> obx_query_prop_count;
+
+  obx_query_prop_op_t<int, Double> obx_query_prop_avg, obx_query_prop_min, obx_query_prop_max, obx_query_prop_sum;
+
+  obx_query_prop_op_t<int, Int64> obx_query_prop_min_int, obx_query_prop_max_int, obx_query_prop_sum_int;
+
+  obx_query_prop_find_native_t<Pointer<OBX_string_array>, Int8> obx_query_prop_string_find;
+  obx_query_prop_find_native_t<Pointer<OBX_int64_array>, Int64> obx_query_prop_int64_find;
+  obx_query_prop_find_native_t<Pointer<OBX_int32_array>, Int32> obx_query_prop_int32_find;
+  obx_query_prop_find_native_t<Pointer<OBX_int16_array>, Int16> obx_query_prop_int16_find;
+  obx_query_prop_find_native_t<Pointer<OBX_int8_array>, Int8> obx_query_prop_int8_find;
+  obx_query_prop_find_native_t<Pointer<OBX_double_array>, Double> obx_query_prop_double_find;
+  obx_query_prop_find_native_t<Pointer<OBX_float_array>, Float> obx_query_prop_float_find;
+
   // Utilities
   obx_bytes_array_t<int> obx_bytes_array;
   obx_bytes_array_set_t<int, int> obx_bytes_array_set;
@@ -170,13 +191,13 @@ class _ObjectBoxBindings {
     obx_supports_bytes_array = _fn<obx_supports_bytes_array_native_t>("obx_supports_bytes_array").asFunction();
     obx_bytes_array_free = _fn<obx_free_native_t<Pointer<OBX_bytes_array>>>("obx_bytes_array_free").asFunction();
     obx_id_array_free = _fn<obx_free_native_t<Pointer<OBX_id_array>>>("obx_id_array_free").asFunction();
-//    obx_string_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_string_array_free").asFunction();
-//    obx_int64_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_int64_array_free").asFunction();
-//    obx_int32_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_int32_array_free").asFunction();
-//    obx_int16_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_int16_array_free").asFunction();
-//    obx_int8_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_int8_array_free").asFunction();
-//    obx_double_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_double_array_free").asFunction();
-//    obx_float_array_free = _fn<obx_free_native_t<Pointer<>>>("obx_float_array_free").asFunction();
+    obx_string_array_free = _fn<obx_free_native_t<Pointer<OBX_string_array>>>('obx_string_array_free').asFunction();
+    obx_int64_array_free = _fn<obx_free_native_t<Pointer<OBX_int64_array>>>('obx_int64_array_free').asFunction();
+    obx_int32_array_free = _fn<obx_free_native_t<Pointer<OBX_int32_array>>>('obx_int32_array_free').asFunction();
+    obx_int16_array_free = _fn<obx_free_native_t<Pointer<OBX_int16_array>>>('obx_int16_array_free').asFunction();
+    obx_int8_array_free = _fn<obx_free_native_t<Pointer<OBX_int8_array>>>('obx_int8_array_free').asFunction();
+    obx_double_array_free = _fn<obx_free_native_t<Pointer<OBX_double_array>>>('obx_double_array_free').asFunction();
+    obx_float_array_free = _fn<obx_free_native_t<Pointer<OBX_float_array>>>('obx_float_array_free').asFunction();
 
     // error info
     obx_last_error_code = _fn<obx_last_error_code_native_t>("obx_last_error_code").asFunction();
@@ -299,6 +320,39 @@ class _ObjectBoxBindings {
 
     obx_query_visit = _fn<obx_query_visit_native_t>("obx_query_visit").asFunction();
 
+    // query property
+    obx_query_prop = _fn<obx_query_prop_t<Uint32>>('obx_query_prop').asFunction();
+    obx_query_prop_close = _fn<obx_query_prop_close_t<Int32>>('obx_query_prop_close').asFunction();
+
+    obx_query_prop_distinct = _fn<obx_query_prop_distinct_t<Int32, Int8>>('obx_query_prop_distinct').asFunction();
+    obx_query_prop_distinct_case =
+        _fn<obx_query_prop_distinct2_t<Int32, Int8>>('obx_query_prop_distinct_case').asFunction();
+
+    obx_query_prop_count = _fn<obx_query_prop_op_t<Int32, Uint64>>('obx_query_prop_count').asFunction();
+    obx_query_prop_avg = _fn<obx_query_prop_op_t<Int32, Double>>('obx_query_prop_avg').asFunction();
+    obx_query_prop_min = _fn<obx_query_prop_op_t<Int32, Double>>('obx_query_prop_min').asFunction();
+    obx_query_prop_max = _fn<obx_query_prop_op_t<Int32, Double>>('obx_query_prop_max').asFunction();
+    obx_query_prop_sum = _fn<obx_query_prop_op_t<Int32, Double>>('obx_query_prop_sum').asFunction();
+
+    obx_query_prop_min_int = _fn<obx_query_prop_op_t<Int32, Int64>>('obx_query_prop_min_int').asFunction();
+    obx_query_prop_max_int = _fn<obx_query_prop_op_t<Int32, Int64>>('obx_query_prop_max_int').asFunction();
+    obx_query_prop_sum_int = _fn<obx_query_prop_op_t<Int32, Int64>>('obx_query_prop_sum_int').asFunction();
+
+    obx_query_prop_string_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_string_array>, Int8>>('obx_query_prop_string_find').asFunction();
+    obx_query_prop_int64_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_int64_array>, Int64>>('obx_query_prop_int64_find').asFunction();
+    obx_query_prop_int32_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_int32_array>, Int32>>('obx_query_prop_int32_find').asFunction();
+    obx_query_prop_int16_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_int16_array>, Int16>>('obx_query_prop_int16_find').asFunction();
+    obx_query_prop_int8_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_int8_array>, Int8>>('obx_query_prop_int8_find').asFunction();
+    obx_query_prop_double_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_double_array>, Double>>('obx_query_prop_double_find').asFunction();
+    obx_query_prop_float_find =
+        _fn<obx_query_prop_find_native_t<Pointer<OBX_float_array>, Float>>('obx_query_prop_float_find').asFunction();
+
     // Utilities
     obx_bytes_array = _fn<obx_bytes_array_t<IntPtr>>("obx_bytes_array").asFunction();
     obx_bytes_array_set = _fn<obx_bytes_array_set_t<Int32, IntPtr>>("obx_bytes_array_set").asFunction();

lib/src/bindings/signatures.dart

@@ -159,6 +159,19 @@ typedef obx_query_visit_native_t = Int32 Function(Pointer<Void> query,
 typedef obx_query_visit_dart_t = int Function(Pointer<Void> query,
     Pointer<NativeFunction<obx_data_visitor_native_t>> visitor, Pointer<Void> user_data, int offset, int limit);
 
+// query property
+
+typedef obx_query_prop_t<T> = Pointer<Void> Function(Pointer<Void> query, T propertyId); // Uint32 -> int
+typedef obx_query_prop_close_t<T> = T Function(Pointer<Void> query); // obx_err -> Int32 -> int
+// note: can not use return type Pointer<T> as it throws off code analysis.
+typedef obx_query_prop_find_native_t<T, V extends NativeType> = T Function(
+    Pointer<Void> query, Pointer<V> value_if_null);
+typedef obx_query_prop_distinct_t<T, V> = T Function(
+    Pointer<Void> query, V distinct); // T = (Int32, int), V = (Int8, int)
+typedef obx_query_prop_distinct2_t<T, V> = T Function(Pointer<Void> query, V distinct, V caseSensitive);
+typedef obx_query_prop_op_t<T, V extends NativeType> = T Function(
+    Pointer<Void> query, Pointer<V> outValue, Pointer<Int64> outCount);
+
 // Utilities
 
 typedef obx_bytes_array_t<SizeT> = Pointer<OBX_bytes_array> Function(SizeT count);

lib/src/bindings/structs.dart

@@ -1,6 +1,6 @@
 import 'dart:ffi';
 import "dart:typed_data" show Uint8List;
-import "package:ffi/ffi.dart" show allocate, free;
+import "package:ffi/ffi.dart" show allocate, free, Utf8;
 import '../common.dart';
 
 // Disable some linter rules for this file
@@ -118,3 +118,72 @@ class OBX_bytes_array extends Struct {
     return result;
   }
 }
+
+class OBX_int8_array extends Struct {
+  Pointer<Int8> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<int> items() => _itemsPtr.asTypedList(count).toList();
+}
+
+class OBX_int16_array extends Struct {
+  Pointer<Int16> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<int> items() => _itemsPtr.asTypedList(count).toList();
+}
+
+class OBX_int32_array extends Struct {
+  Pointer<Int32> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<int> items() => _itemsPtr.asTypedList(count).toList();
+}
+
+class OBX_int64_array extends Struct {
+  Pointer<Int64> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<int> items() => _itemsPtr.asTypedList(count).toList();
+}
+
+class OBX_string_array extends Struct {
+  Pointer<Pointer<Uint8>> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<String> items() {
+    final list = <String>[];
+    for (var i = 0; i < count; i++) {
+      list.add(Utf8.fromUtf8(_itemsPtr.elementAt(i).value.cast<Utf8>()));
+    }
+    return list;
+  }
+}
+
+class OBX_float_array extends Struct {
+  Pointer<Float> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<double> items() => _itemsPtr.asTypedList(count).toList();
+}
+
+class OBX_double_array extends Struct {
+  Pointer<Double> _itemsPtr;
+
+  @IntPtr() // size_t
+  int count;
+
+  List<double> items() => _itemsPtr.asTypedList(count).toList();
+}