WiP, Preview: relations

generator/integration-tests/common.dart

@@ -59,13 +59,18 @@ commonModelTests(ModelDefinition defs, ModelInfo jsonModel) {
         jsonModel.retiredEntityUids);
   });
 
-  // TODO when indexes are available
+// TODO when indexes are available
+// TODO see one-liner in the next lastRelationId test
 //  test('lastIndexId', () {
 //    testLastId(defs.model.lastIndexId, defs.model.entities.map((el) => ...), jsonModel.retiredIndexUids);
 //  });
 
-  // TODO when relations are available
-//  test('lastRelationId', () {
-//    testLastId(defs.model.lastRelationId, defs.model.entities.map((el) => ...), jsonModel.retiredRelationUids);
-//  });
+  test('lastRelationId', () {
+    testLastId(
+        defs.model.lastRelationId,
+        defs.model.entities
+            .map((e) => e.properties.where((p) => p.isRelation))
+            .fold([], (a, b) => a + b).map((e) => e.id),
+        jsonModel.retiredRelationUids);
+  });
 }

generator/lib/src/code_builder.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:io';
+import 'dart:math';
 import 'dart:convert';
 import 'package:build/build.dart';
 import 'package:glob/glob.dart';
@@ -82,6 +83,7 @@ class CodeBuilder extends Builder {
 
     // merge existing model and annotated model that was just read, then write new final model to file
     merge(model, entities);
+    assignLastPropertyIds(model);
     model.validate();
 
     // write model info
@@ -93,6 +95,20 @@ class CodeBuilder extends Builder {
     return model;
   }
 
+  void assignLastPropertyIds(ModelInfo model) {
+    model.entities.forEach((e) {
+      e.properties.forEach((p) {
+        // if (p.isIndexer) {
+        //   model.lastIndexId = p.id; }else
+        if (p.isToOne) {
+          model.lastIndexId = p.relIndexId;
+        } else if (p.isToMany) {
+          model.lastRelationId = p.relationId;
+        }
+      });
+    });
+  }
+
   void updateCode(
       ModelInfo model, List<String> infoFiles, BuildStep buildStep) async {
     // transform '/lib/path/entity.objectbox.info' to 'path/entity.dart'
@@ -131,6 +147,17 @@ class CodeBuilder extends Builder {
     entities.forEach((entity) => mergeEntity(model, entity));
   }
 
+  int generateUid(int seed, Set<int> prohibited) {
+    final rng = Random(seed + DateTime.now().millisecondsSinceEpoch);
+    for (int i = 0; i < 1000; i++) {
+      var uid = rng.nextInt(1 << 32);
+      uid |= rng.nextInt(1 << 32) << 32;
+      uid &= ~(1 << 63);
+      if (!prohibited.contains(uid)) return uid;
+    }
+    return 0;
+  }
+
   void mergeProperty(ModelEntity entity, ModelProperty prop) {
     final propInModel = entity.findSameProperty(prop);
     if (propInModel == null) {
@@ -140,6 +167,10 @@ class CodeBuilder extends Builder {
       propInModel.name = prop.name;
       propInModel.type = prop.type;
       propInModel.flags = prop.flags;
+      if (prop.type.isRelation) {
+        propInModel.targetEntityName = prop.targetEntityName;
+        propInModel.relIndexId = prop.relIndexId;
+      }
     }
   }
 
@@ -160,6 +191,50 @@ class CodeBuilder extends Builder {
     // here, the entity was found already and entityInModel and readEntity might differ, i.e. conflicts need to be resolved, so merge all properties first
     entity.properties.forEach((p) => mergeProperty(entityInModel, p));
 
+    // one to one relation: get the highest relIndexId.id
+    // TODO Ask: Do we want to repair contiguous ids, if one prop is removed in the middle?
+    var relIndexIdCounter = entityInModel.properties
+        .where((p) => p.isToOne && p.relIndexId != null)
+        .map((p) => p.relIndexId.id)
+        .fold(1, (a, b) => a < b ? b : a);
+
+    // Prohibit reuse of indexUids
+    final avoidSameUidSet = Set<int>()..addAll(modelInfo.retiredIndexUids);
+
+    // one to one relation
+    entityInModel.properties.where((p) => p.isToOne).forEach((p) {
+      if (p.relIndexId == null) {
+        p.relIndexId = IdUid.empty();
+      }
+      if (p.relIndexId.isEmpty) {
+        p.relIndexId.id = relIndexIdCounter++;
+        p.relIndexId.uid = generateUid(entityInModel.id.uid, avoidSameUidSet);
+        avoidSameUidSet.add(p.relIndexId.uid);
+      }
+    });
+
+    // many to many relation
+    var relationIdCounter = entityInModel.properties
+        .where((p) => p.isToMany && p.relationId != null)
+        .map((p) => p.relationId.id)
+        .fold(1, (a, b) => a < b ? b : a);
+
+    final targetEntityMap = <String, IdUid>{};
+    final mapEntityNameToId =
+        modelInfo.entities.forEach((e) => targetEntityMap[e.name] = e.id);
+    entityInModel.properties.where((p) => p.isToMany).forEach((p) {
+      if (p.relationId == null) {
+        p.relationId = IdUid.empty();
+      }
+      if (p.relationId.isEmpty) {
+        p.relationId.id = relationIdCounter++;
+        p.relationId.uid = generateUid(entityInModel.id.uid, avoidSameUidSet);
+        avoidSameUidSet.add(p.relationId.uid);
+      }
+
+      p.targetEntityId = targetEntityMap[p.targetEntityName];
+    });
+
     // then remove all properties not present anymore in readEntity
     entityInModel.properties
         .where((p) => entity.findSameProperty(p) == null)

generator/lib/src/code_chunks.dart

@@ -57,6 +57,9 @@ class CodeChunks {
         case OBXPropertyType.String:
           fieldType = "String";
           break;
+        case OBXPropertyType.Relation:
+          fieldType = 'Relation';
+          break;
         float:
         case OBXPropertyType.Double:
           fieldType = "Double";
@@ -80,8 +83,11 @@ class CodeChunks {
               "Unsupported property type (${prop.type}): ${entity.name}.${name}");
       }
 
+      final relationTypeGenericParam =
+          prop.type == OBXPropertyType.Relation ? '<${prop.targetEntityName}>' : '';
+
       ret.add("""
-        static final ${name} = Query${fieldType}Property(entityId:${entity.id.id}, propertyId:${prop.id.id}, obxType:${prop.type});
+        static final ${name} = Query${fieldType}Property$relationTypeGenericParam(entityId:${entity.id.id}, propertyId:${prop.id.id}, obxType:${prop.type});
         """);
     }
     return ret.join();

generator/lib/src/entity_resolver.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
 import 'package:build/build.dart';
 import 'package:objectbox/objectbox.dart' as obx;
 import 'package:objectbox/src/bindings/constants.dart';
@@ -17,7 +18,7 @@ class EntityResolver extends Builder {
     '.dart': [suffix]
   };
 
-  final _annotationChecker = const TypeChecker.fromRuntime(obx.Entity);
+  final _entityChecker = const TypeChecker.fromRuntime(obx.Entity);
   final _propertyChecker = const TypeChecker.fromRuntime(obx.Property);
   final _idChecker = const TypeChecker.fromRuntime(obx.Id);
   final _transientChecker = const TypeChecker.fromRuntime(obx.Transient);
@@ -30,9 +31,13 @@ class EntityResolver extends Builder {
 
     // generate for all entities
     final entities = <Map<String, dynamic>>[];
-    for (var annotatedEl in libReader.annotatedWith(_annotationChecker)) {
-      entities.add(generateForAnnotatedElement(
-              annotatedEl.element, annotatedEl.annotation)
+    final annotatedWithEntity = libReader.annotatedWith(_entityChecker);
+    final entityNames = annotatedWithEntity.map((a) => a.element.name).toSet();
+    final entityNamesAsList =
+        annotatedWithEntity.map((a) => 'List<${a.element.name}>').toSet();
+    for (var annotatedEl in annotatedWithEntity) {
+      entities.add(generateForAnnotatedElement(annotatedEl.element,
+              annotatedEl.annotation, entityNames, entityNamesAsList)
           .toMap());
     }
 
@@ -44,7 +49,10 @@ class EntityResolver extends Builder {
   }
 
   ModelEntity generateForAnnotatedElement(
-      Element elementBare, ConstantReader annotation) {
+      Element elementBare,
+      ConstantReader annotation,
+      Set<String> relatableEntityNames,
+      Set<String> relatableEntityNamesAsList) {
     if (elementBare is! ClassElement) {
       throw InvalidGenerationSourceError(
           "in target ${elementBare.name}: annotated element isn't a class");
@@ -70,6 +78,7 @@ class EntityResolver extends Builder {
 
       int fieldType, flags = 0;
       int propUid;
+      final dartTypeString = f.type.toString().replaceAll('*', '');
 
       if (_idChecker.hasAnnotationOfExact(f)) {
         if (hasIdProperty) {
@@ -96,7 +105,7 @@ class EntityResolver extends Builder {
       }
 
       if (fieldType == null) {
-        var fieldTypeDart = f.type;
+        final fieldTypeDart = f.type;
 
         if (fieldTypeDart.isDartCoreInt) {
           // dart: 8 bytes
@@ -112,6 +121,9 @@ class EntityResolver extends Builder {
           // dart: 8 bytes
           // ob: 8 bytes
           fieldType = OBXPropertyType.Double;
+        } else if (areRelated(
+            dartTypeString, relatableEntityNames, relatableEntityNamesAsList)) {
+          fieldType = OBXPropertyType.Relation;
         } else {
           log.warning(
               "  skipping property '${f.name}' in entity '${element.name}', as it has the unsupported type '${fieldTypeDart.toString()}'");
@@ -120,8 +132,20 @@ class EntityResolver extends Builder {
       }
 
       // create property (do not use readEntity.createProperty in order to avoid generating new ids)
-      final prop =
-          ModelProperty(IdUid.empty(), f.name, fieldType, flags, readEntity);
+      final isRelation = fieldType == OBXPropertyType.Relation;
+
+      // setup relations
+      final isToOne =
+          isRelation && areRelated(dartTypeString, relatableEntityNames);
+      final isToMany =
+          isRelation && areRelated(dartTypeString, relatableEntityNamesAsList);
+      final prop = ModelProperty(
+          IdUid.empty(), f.name, fieldType, flags, readEntity,
+          targetEntityName: isRelation ? dartTypeString : null,
+          relIndexId: isToOne ? IdUid.empty() : null,
+          relationId: isToMany ? IdUid.empty() : null,
+          targetEntityId: isToMany ? IdUid.empty() : null);
+
       if (propUid != null) prop.id.uid = propUid;
       readEntity.properties.add(prop);
 
@@ -137,4 +161,7 @@ class EntityResolver extends Builder {
 
     return readEntity;
   }
+
+  bool areRelated(String typeString, Set<String> s1, [Set<String> s2]) =>
+      s1.contains(typeString) || (s2 != null && s2.contains(typeString));
 }

generator/pubspec.yaml

@@ -5,7 +5,7 @@ homepage: https://objectbox.io
 description: ObjectBox binding code generator - finds annotated entities and adds them to the ObjectBox DB model.
 
 environment:
-  sdk: ">=2.5.0 <3.0.0"
+  sdk: ">=2.6.0 <3.0.0"
 
 dependencies:
   objectbox: 0.8.0

lib/objectbox.dart

@@ -12,3 +12,4 @@ export 'src/model.dart';
 export 'src/modelinfo/index.dart';
 export 'src/query/query.dart';
 export 'src/store.dart';
+export 'src/util.dart';