Sqlite: Add callback method

Sometimes it is better to have a callback instead of returning a container.
The call has to manage the state if an exception is called but otherwise
it will reduce the memory footprint. There will be to a RETURNING
to Sqlite which will read back values as you write.

Change-Id: I7eb49850e2c76f883a03277b31c5e713e9774c92
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/libs/sqlite/sqlitebasestatement.h

@@ -37,9 +37,10 @@
 #include <utils/span.h>
 
 #include <cstdint>
+#include <functional>
 #include <memory>
-#include <type_traits>
 #include <tuple>
+#include <type_traits>
 
 using std::int64_t;
 
@@ -316,6 +317,25 @@ public:
         return statement.template fetchValue<Type>(0);
     }
 
+    template<int ResultTypeCount = 1, typename Callable, typename... QueryTypes>
+    void readCallback(Callable &&callable, const QueryTypes &...queryValues)
+    {
+        BaseStatement::checkColumnCount(ResultTypeCount);
+
+        Resetter resetter{*this};
+
+        bindValues(queryValues...);
+
+        while (BaseStatement::next()) {
+            auto control = callCallable<ResultTypeCount>(callable);
+
+            if (control == CallbackControl::Abort)
+                break;
+        }
+
+        resetter.reset();
+    }
+
 protected:
     ~StatementImplementation() = default;
 
@@ -398,6 +418,18 @@ private:
         return assignValue<ResultOptionalType>(std::make_integer_sequence<int, ResultTypeCount>{});
     }
 
+    template<typename Callable, int... ColumnIndices>
+    CallbackControl callCallable(Callable &&callable, std::integer_sequence<int, ColumnIndices...>)
+    {
+        return std::invoke(callable, ValueGetter(*this, ColumnIndices)...);
+    }
+
+    template<int ResultTypeCount, typename Callable>
+    CallbackControl callCallable(Callable &&callable)
+    {
+        return callCallable(callable, std::make_integer_sequence<int, ResultTypeCount>{});
+    }
+
     template<typename ValueType>
     void bindValuesByIndex(int index, const ValueType &value)
     {

src/libs/sqlite/sqliteglobal.h

@@ -68,4 +68,6 @@ enum class ChangeType : int { Delete = 9, Insert = 18, Update = 23 };
 
 enum class byte : unsigned char {};
 
+enum class CallbackControl : unsigned char { Continue, Abort };
+
 } // namespace Sqlite

src/libs/sqlite/sqlitereadstatement.h

@@ -34,9 +34,10 @@ class SQLITE_EXPORT ReadStatement final : protected StatementImplementation<Base
 public:
     explicit ReadStatement(Utils::SmallStringView sqlStatement, Database &database);
 
+    using StatementImplementation::readCallback;
+    using StatementImplementation::toValue;
     using StatementImplementation::value;
     using StatementImplementation::values;
-    using StatementImplementation::toValue;
 
 protected:
     void checkIsReadOnlyStatement();

src/libs/sqlite/sqlitereadwritestatement.h

@@ -37,9 +37,10 @@ public:
     ReadWriteStatement(Utils::SmallStringView sqlStatement, Database &database);
 
     using StatementImplementation::execute;
+    using StatementImplementation::readCallback;
+    using StatementImplementation::toValue;
     using StatementImplementation::value;
     using StatementImplementation::values;
-    using StatementImplementation::toValue;
     using StatementImplementation::write;
 };
 

tests/unit/unittest/mocksqlitestatement.h

@@ -42,6 +42,7 @@ public:
     MOCK_CONST_METHOD1(fetchLongLongValue, long long (int));
     MOCK_CONST_METHOD1(fetchDoubleValue, double (int));
     MOCK_CONST_METHOD1(fetchSmallStringValue, Utils::SmallString (int));
+    MOCK_CONST_METHOD1(fetchSmallStringViewValue, Utils::SmallStringView(int));
     MOCK_CONST_METHOD1(fetchPathStringValue, Utils::PathString (int));
 
     template<typename Type>

tests/unit/unittest/sqlitestatement-test.cpp

@@ -946,4 +946,90 @@ TEST_F(SqliteStatement, ThrowInvalidColumnFetchedForToManyArgumentsForToValues)
                  Sqlite::ColumnCountDoesNotMatch);
 }
 
+TEST_F(SqliteStatement, ReadCallback)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    ReadStatement statement("SELECT name, value FROM test", database);
+
+    EXPECT_CALL(callbackMock, Call(Eq("bar"), Eq(1)));
+    EXPECT_CALL(callbackMock, Call(Eq("foo"), Eq(2)));
+    EXPECT_CALL(callbackMock, Call(Eq("poo"), Eq(3)));
+
+    statement.readCallback<2>(callbackMock.AsStdFunction());
+}
+
+TEST_F(SqliteStatement, ReadCallbackCalledWithArguments)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    ReadStatement statement("SELECT name, value FROM test WHERE value=?", database);
+
+    EXPECT_CALL(callbackMock, Call(Eq("foo"), Eq(2)));
+
+    statement.readCallback<2>(callbackMock.AsStdFunction(), 2);
+}
+
+TEST_F(SqliteStatement, ReadCallbackAborts)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    ReadStatement statement("SELECT name, value FROM test ORDER BY name", database);
+
+    EXPECT_CALL(callbackMock, Call(Eq("bar"), Eq(1)));
+    EXPECT_CALL(callbackMock, Call(Eq("foo"), Eq(2))).WillOnce(Return(Sqlite::CallbackControl::Abort));
+    EXPECT_CALL(callbackMock, Call(Eq("poo"), Eq(3))).Times(0);
+
+    statement.readCallback<2>(callbackMock.AsStdFunction());
+}
+
+TEST_F(SqliteStatement, ThrowInvalidColumnFetchedForToManyArgumentsForReadCallback)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView)> callbackMock;
+    SqliteTestStatement statement("SELECT name, number FROM test", database);
+
+    ASSERT_THROW(statement.readCallback<1>(callbackMock.AsStdFunction()),
+                 Sqlite::ColumnCountDoesNotMatch);
+}
+
+TEST_F(SqliteStatement, ReadCallbackCallsResetAfterCallbacks)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    MockSqliteStatement mockStatement;
+
+    EXPECT_CALL(mockStatement, reset());
+
+    mockStatement.readCallback<2>(callbackMock.AsStdFunction());
+}
+
+TEST_F(SqliteStatement, ReadCallbackCallsResetAfterCallbacksAborts)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    MockSqliteStatement mockStatement;
+    ON_CALL(callbackMock, Call(_, _)).WillByDefault(Return(Sqlite::CallbackControl::Abort));
+
+    EXPECT_CALL(mockStatement, reset());
+
+    mockStatement.readCallback<2>(callbackMock.AsStdFunction());
+}
+
+TEST_F(SqliteStatement, ReadCallbackThrowsForError)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    MockSqliteStatement mockStatement;
+    ON_CALL(mockStatement, next()).WillByDefault(Throw(Sqlite::StatementHasError("")));
+
+    ASSERT_THROW(mockStatement.readCallback<2>(callbackMock.AsStdFunction()),
+                 Sqlite::StatementHasError);
+}
+
+TEST_F(SqliteStatement, ReadCallbackCallsResetIfExceptionIsThrown)
+{
+    MockFunction<Sqlite::CallbackControl(Utils::SmallStringView, long long)> callbackMock;
+    MockSqliteStatement mockStatement;
+    ON_CALL(mockStatement, next()).WillByDefault(Throw(Sqlite::StatementHasError("")));
+
+    EXPECT_CALL(mockStatement, reset());
+
+    EXPECT_THROW(mockStatement.readCallback<2>(callbackMock.AsStdFunction()),
+                 Sqlite::StatementHasError);
+}
+
 } // namespace