Introduce flag to generate private watch methods

moor/build.yaml

@@ -0,0 +1,6 @@
+targets:
+  $default:
+    builders:
+      moor_generator:
+        options:
+          generate_private_watch_methods: true

moor/example/example.dart

@@ -37,7 +37,19 @@ class IngredientInRecipes extends Table {
   IntColumn get amountInGrams => integer().named('amount')();
 }
 
-@UseMoor(tables: [Categories, Recipes, Ingredients, IngredientInRecipes])
+@UseMoor(
+  tables: [Categories, Recipes, Ingredients, IngredientInRecipes],
+  queries: {
+    // query to load the total weight for each recipe by loading all ingredients
+    // and taking the sum of their amountInGrams.
+    '_totalWeight': '''
+      SELECT r.title, SUM(ir.amount) AS total_weight
+        FROM recipes r
+        INNER JOIN recipe_ingredients ir ON ir.recipe = r.id
+      GROUP BY r.id
+     '''
+  },
+)
 class Database extends _$Database {
   Database(QueryExecutor e) : super(e);
 

moor/example/example.g.dart

@@ -802,6 +802,15 @@ class $IngredientInRecipesTable extends IngredientInRecipes
   }
 }
 
+class TotalWeightResult {
+  final String title;
+  final int totalWeight;
+  TotalWeightResult({
+    this.title,
+    this.totalWeight,
+  });
+}
+
 abstract class _$Database extends GeneratedDatabase {
   _$Database(QueryExecutor e) : super(const SqlTypeSystem.withDefaults(), e);
   $CategoriesTable _categories;
@@ -813,6 +822,31 @@ abstract class _$Database extends GeneratedDatabase {
   $IngredientInRecipesTable _ingredientInRecipes;
   $IngredientInRecipesTable get ingredientInRecipes =>
       _ingredientInRecipes ??= $IngredientInRecipesTable(this);
+  TotalWeightResult _rowToTotalWeightResult(QueryRow row) {
+    return TotalWeightResult(
+      title: row.readString('title'),
+      totalWeight: row.readInt('total_weight'),
+    );
+  }
+
+  Future<List<TotalWeightResult>> _totalWeight(
+      {@Deprecated('No longer needed with Moor 1.6 - see the changelog for details')
+          QueryEngine operateOn}) {
+    return (operateOn ?? this).customSelect(
+        '      SELECT r.title, SUM(ir.amount) AS total_weight\n        FROM recipes r\n        INNER JOIN recipe_ingredients ir ON ir.recipe = r.id\n      GROUP BY r.id\n     ',
+        variables: []).then((rows) => rows.map(_rowToTotalWeightResult).toList());
+  }
+
+  Stream<List<TotalWeightResult>> _watchTotalWeight() {
+    return customSelectStream(
+        '      SELECT r.title, SUM(ir.amount) AS total_weight\n        FROM recipes r\n        INNER JOIN recipe_ingredients ir ON ir.recipe = r.id\n      GROUP BY r.id\n     ',
+        variables: [],
+        readsFrom: {
+          recipes,
+          ingredientInRecipes
+        }).map((rows) => rows.map(_rowToTotalWeightResult).toList());
+  }
+
   @override
   List<TableInfo> get allTables =>
       [categories, recipes, ingredients, ingredientInRecipes];

moor_generator/lib/moor_generator.dart

@@ -5,9 +5,7 @@ import 'package:source_gen/source_gen.dart';
 import 'package:moor_generator/src/moor_generator.dart';
 
 Builder moorBuilder(BuilderOptions options) {
-  final writeFromString =
-      options.config['write_from_json_string_constructor'] as bool ?? false;
-  final parsedOptions = MoorOptions(writeFromString);
+  final parsedOptions = MoorOptions.fromBuilder(options.config);
 
   return SharedPartBuilder(
     [

moor_generator/lib/src/dao_generator.dart

@@ -61,7 +61,7 @@ class DaoGenerator extends GeneratorForAnnotation<UseDao> {
 
     final writtenMappingMethods = <String>{};
     for (var query in parsedDao.queries) {
-      QueryWriter(query, writtenMappingMethods).writeInto(buffer);
+      QueryWriter(query, session, writtenMappingMethods).writeInto(buffer);
     }
 
     buffer.write('}');

moor_generator/lib/src/state/options.dart

@@ -1,7 +1,25 @@
 class MoorOptions {
   final bool generateFromJsonStringConstructor;
 
-  MoorOptions(this.generateFromJsonStringConstructor);
+  /// A bug in the generator generates public watch* methods, even if the query
+  /// name starts with an underscore. Fixing this would be a breaking change, so
+  /// we introduce a flag that will be the default behavior in the next breaking
+  /// moor version.
+  final bool fixPrivateWatchMethods;
 
-  const MoorOptions.defaults() : generateFromJsonStringConstructor = false;
+  MoorOptions(
+      this.generateFromJsonStringConstructor, this.fixPrivateWatchMethods);
+
+  factory MoorOptions.fromBuilder(Map<String, dynamic> config) {
+    final writeFromString =
+        config['write_from_json_string_constructor'] as bool ?? false;
+    final fixWatchMethods =
+        config['generate_private_watch_methods'] as bool ?? false;
+
+    return MoorOptions(writeFromString, fixWatchMethods);
+  }
+
+  const MoorOptions.defaults()
+      : generateFromJsonStringConstructor = false,
+        fixPrivateWatchMethods = false;
 }

moor_generator/lib/src/writer/database_writer.dart

@@ -62,7 +62,7 @@ class DatabaseWriter {
     // Write implementation for query methods
     final writtenMappingMethods = <String>{};
     for (var query in db.queries) {
-      QueryWriter(query, writtenMappingMethods).writeInto(buffer);
+      QueryWriter(query, session, writtenMappingMethods).writeInto(buffer);
     }
 
     // Write List of tables, close bracket for class

moor_generator/lib/src/writer/query_writer.dart

@@ -2,6 +2,7 @@ import 'dart:math' show max;
 
 import 'package:moor_generator/src/model/specified_column.dart';
 import 'package:moor_generator/src/model/sql_query.dart';
+import 'package:moor_generator/src/state/session.dart';
 import 'package:moor_generator/src/utils/string_escaper.dart';
 import 'package:recase/recase.dart';
 import 'package:sqlparser/sqlparser.dart';
@@ -15,12 +16,13 @@ const highestAssignedIndexVar = '\$highestIndex';
 /// should be included in a generated database or dao class.
 class QueryWriter {
   final SqlQuery query;
+  final GeneratorSession session;
   SqlSelectQuery get _select => query as SqlSelectQuery;
   UpdatingQuery get _update => query as UpdatingQuery;
 
   final Set<String> _writtenMappingMethods;
 
-  QueryWriter(this.query, this._writtenMappingMethods);
+  QueryWriter(this.query, this.session, this._writtenMappingMethods);
 
   /// The expanded sql that we insert into queries whenever an array variable
   /// appears. For the query "SELECT * FROM t WHERE x IN ?", we generate
@@ -102,9 +104,17 @@ class QueryWriter {
   }
 
   void _writeStreamReader(StringBuffer buffer) {
+    // turning the query name into pascal case will remove underscores
     final upperQueryName = ReCase(query.name).pascalCase;
-    buffer.write(
-        'Stream<List<${_select.resultClassName}>> watch$upperQueryName(');
+
+    String methodName;
+    if (session.options.fixPrivateWatchMethods && query.name.startsWith('_')) {
+      methodName = '_watch$upperQueryName';
+    } else {
+      methodName = 'watch$upperQueryName';
+    }
+
+    buffer.write('Stream<List<${_select.resultClassName}>> $methodName(');
     // don't supply an engine override parameter because select streams cannot
     // be used in transaction or similar context, only on the main database
     // engine.