Correctly write variables in analyzed queries

moor/test/data/tables/todos.dart

@@ -56,9 +56,16 @@ class TableWithoutPK extends Table {
   tables: [TodosTable, Categories, Users, SharedTodos, TableWithoutPK],
   queries: [
     Sql(
-        'allTodosWithCategory',
-        'SELECT t.*, c.id as catId, c."desc" as catDesc '
-            'FROM todos t INNER JOIN categories c ON c.id = t.category'),
+      'allTodosWithCategory',
+      'SELECT t.*, c.id as catId, c."desc" as catDesc '
+          'FROM todos t INNER JOIN categories c ON c.id = t.category',
+    ),
+    Sql(
+        'todosForUser',
+        'SELECT t.* FROM todos t '
+            'INNER JOIN shared_todos st ON st.todo = t.id '
+            'INNER JOIN users u ON u.id = st.user '
+            'WHERE u.id = :user'),
   ],
 )
 class TodoDb extends _$TodoDb {

moor/test/data/tables/todos.g.dart

@@ -1024,6 +1024,21 @@ class AllTodosWithCategoryResult {
   });
 }
 
+class TodosForUserResult {
+  final int id;
+  final String title;
+  final String content;
+  final DateTime targetDate;
+  final int category;
+  TodosForUserResult({
+    this.id,
+    this.title,
+    this.content,
+    this.targetDate,
+    this.category,
+  });
+}
+
 abstract class _$TodoDb extends GeneratedDatabase {
   _$TodoDb(QueryExecutor e) : super(const SqlTypeSystem.withDefaults(), e);
   $TodosTableTable _todosTable;
@@ -1051,16 +1066,44 @@ abstract class _$TodoDb extends GeneratedDatabase {
 
   Future<List<AllTodosWithCategoryResult>> allTodosWithCategory() {
     return customSelect(
-            'SELECT t.*, c.id as catId, c."desc" as catDesc FROM todos t INNER JOIN categories c ON c.id = t.category')
+            'SELECT t.*, c.id as catId, c."desc" as catDesc FROM todos t INNER JOIN categories c ON c.id = t.category',
+            variables: [])
         .then((rows) => rows.map(_rowToAllTodosWithCategoryResult).toList());
   }
 
   Stream<List<AllTodosWithCategoryResult>> watchAllTodosWithCategory() {
     return customSelectStream(
-            'SELECT t.*, c.id as catId, c."desc" as catDesc FROM todos t INNER JOIN categories c ON c.id = t.category')
+            'SELECT t.*, c.id as catId, c."desc" as catDesc FROM todos t INNER JOIN categories c ON c.id = t.category',
+            variables: [])
         .map((rows) => rows.map(_rowToAllTodosWithCategoryResult).toList());
   }
 
+  TodosForUserResult _rowToTodosForUserResult(QueryRow row) {
+    return TodosForUserResult(
+      id: row.readInt('id'),
+      title: row.readString('title'),
+      content: row.readString('content'),
+      targetDate: row.readDateTime('target_date'),
+      category: row.readInt('category'),
+    );
+  }
+
+  Future<List<TodosForUserResult>> todosForUser(int user) {
+    return customSelect(
+        'SELECT t.* FROM todos t INNER JOIN shared_todos st ON st.todo = t.id INNER JOIN users u ON u.id = st.user WHERE u.id = :user',
+        variables: [
+          Variable.withInt(user),
+        ]).then((rows) => rows.map(_rowToTodosForUserResult).toList());
+  }
+
+  Stream<List<TodosForUserResult>> watchTodosForUser(int user) {
+    return customSelectStream(
+        'SELECT t.* FROM todos t INNER JOIN shared_todos st ON st.todo = t.id INNER JOIN users u ON u.id = st.user WHERE u.id = :user',
+        variables: [
+          Variable.withInt(user),
+        ]).map((rows) => rows.map(_rowToTodosForUserResult).toList());
+  }
+
   @override
   List<TableInfo> get allTables =>
       [todosTable, categories, users, sharedTodos, tableWithoutPK];

moor_generator/lib/src/model/specified_column.dart

@@ -49,6 +49,17 @@ const Map<ColumnType, String> readFromMethods = {
   ColumnType.real: 'readDouble',
 };
 
+/// Maps from a column type to code that can be used to create a variable of the
+/// respective type.
+const Map<ColumnType, String> createVariable = {
+  ColumnType.boolean: 'Variable.withBool',
+  ColumnType.text: 'Variable.withString',
+  ColumnType.integer: 'Variable.withInt',
+  ColumnType.datetime: 'Variable.withDateTime',
+  ColumnType.blob: 'Variable.withBlob',
+  ColumnType.real: 'Variable.withReal',
+};
+
 /// A column, as specified by a getter in a table.
 class SpecifiedColumn {
   /// The getter name of this column in the table class. It will also be used

moor_generator/lib/src/model/sql_query.dart

@@ -8,8 +8,9 @@ final _leadingDigits = RegExp(r'^\d*');
 abstract class SqlQuery {
   final String name;
   final String sql;
+  final List<FoundVariable> variables;
 
-  SqlQuery(this.name, this.sql);
+  SqlQuery(this.name, this.sql, this.variables);
 }
 
 class SqlSelectQuery extends SqlQuery {
@@ -18,8 +19,9 @@ class SqlSelectQuery extends SqlQuery {
 
   String get resultClassName => '${ReCase(name).pascalCase}Result';
 
-  SqlSelectQuery(String name, String sql, this.readsFrom, this.resultSet)
-      : super(name, sql);
+  SqlSelectQuery(String name, String sql, List<FoundVariable> variables,
+      this.readsFrom, this.resultSet)
+      : super(name, sql, variables);
 }
 
 class InferredResultSet {
@@ -70,3 +72,14 @@ class ResultColumn {
 
   ResultColumn(this.name, this.type, this.nullable);
 }
+
+class FoundVariable {
+  int index;
+  String name;
+  final ColumnType type;
+
+  FoundVariable(this.index, this.name, this.type);
+
+  String get dartParameterName =>
+      name?.replaceAll(_illegalChars, '') ?? 'var$index';
+}

moor_generator/lib/src/parser/sql/sql_parser.dart

@@ -121,7 +121,33 @@ class SqlParser {
     }
 
     final resultSet = InferredResultSet(null, moorColumns);
-    foundQueries.add(
-        SqlSelectQuery(queryName, ctx.sql, moorTables.toList(), resultSet));
+    final foundVars = _extractVariables(ctx);
+    foundQueries.add(SqlSelectQuery(
+        queryName, ctx.sql, foundVars, moorTables.toList(), resultSet));
+  }
+
+  List<FoundVariable> _extractVariables(AnalysisContext ctx) {
+    // this contains variable references. For instance, SELECT :a = :a would
+    // contain two entries, both referring to the same variable. To do that,
+    // we use the fact that each variable has a unique index.
+    final usedVars = ctx.root.allDescendants.whereType<Variable>().toList()
+      ..sort((a, b) => a.resolvedIndex.compareTo(b.resolvedIndex));
+
+    final foundVariables = <FoundVariable>[];
+    var currentIndex = 0;
+
+    for (var used in usedVars) {
+      if (used.resolvedIndex == currentIndex) {
+        continue; // already handled
+      }
+
+      currentIndex++;
+      final name = (used is ColonNamedVariable) ? used.name : null;
+      final type = _resolvedToMoor(ctx.typeOf(used).type);
+
+      foundVariables.add(FoundVariable(currentIndex, name, type));
+    }
+
+    return foundVariables;
   }
 }

moor_generator/lib/src/writer/query_writer.dart

@@ -11,24 +11,6 @@ class QueryWriter {
 
   QueryWriter(this.query);
 
-  /* The generated code will look like:
-    Future<List<AllTodosWithCategoryResult>> allTodosWithCategory() {
-    return customSelect('', variables: [])
-        .then((rows) => rows.map(_rowToAllT).toList());
-  }
-
-  Stream<List<AllTodosWithCategoryResult>> watchAllTodosWithCategory() {
-    return customSelectStream('', variables: [])
-        .map((rows) => rows.map(_rowToAllT).toList());
-  }
-
-  AllTodosWithCategoryResult _rowToAllT(QueryRow row) {
-    return AllTodosWithCategoryResult(
-      id: row.readInt('id'),
-    );
-  }
-   */
-
   void writeInto(StringBuffer buffer) {
     if (query is SqlSelectQuery) {
       _writeSelect(buffer);
@@ -63,9 +45,14 @@ class QueryWriter {
   }
 
   void _writeOneTimeReader(StringBuffer buffer) {
+    buffer.write('Future<List<${_select.resultClassName}>> ${query.name}(');
+    _writeParameters(buffer);
     buffer
-      ..write('Future<List<${_select.resultClassName}>> ${query.name}() {\n')
-      ..write('return customSelect(${asDartLiteral(query.sql)})')
+      ..write(') {\n')
+      ..write('return customSelect(${asDartLiteral(query.sql)},');
+    _writeVariables(buffer);
+    buffer
+      ..write(')')
       ..write(
           '.then((rows) => rows.map(${_nameOfMappingMethod()}).toList());\n')
       ..write('\n}\n');
@@ -73,11 +60,36 @@ class QueryWriter {
 
   void _writeStreamReader(StringBuffer buffer) {
     final upperQueryName = ReCase(query.name).pascalCase;
+    buffer.write(
+        'Stream<List<${_select.resultClassName}>> watch$upperQueryName(');
+    _writeParameters(buffer);
     buffer
-      ..write('Stream<List<${_select.resultClassName}>> watch$upperQueryName')
-      ..write('() {\n')
-      ..write('return customSelectStream(${asDartLiteral(query.sql)})')
+      ..write(') {\n')
+      ..write('return customSelectStream(${asDartLiteral(query.sql)},');
+    _writeVariables(buffer);
+    buffer
+      ..write(')')
       ..write('.map((rows) => rows.map(${_nameOfMappingMethod()}).toList());\n')
       ..write('\n}\n');
   }
+
+  void _writeParameters(StringBuffer buffer) {
+    final paramList = query.variables
+        .map((v) => '${dartTypeNames[v.type]} ${v.dartParameterName}')
+        .join(', ');
+
+    buffer.write(paramList);
+  }
+
+  void _writeVariables(StringBuffer buffer) {
+    buffer..write('variables: [');
+
+    for (var variable in query.variables) {
+      buffer
+        ..write(createVariable[variable.type])
+        ..write('(${variable.dartParameterName}),');
+    }
+
+    buffer..write(']');
+  }
 }