CppTools: Fix indentation for concatenated strings

Change-Id: I801a56804e7873be75a9ebc085dc3f4a2d64ea35
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cpptools/cppcodeformatter.cpp

@@ -564,6 +564,13 @@ void CodeFormatter::recalculateStateAfter(const QTextBlock &block)
         case cpp_macro_cont:
             break;
 
+        case string_open:
+            if (!m_currentToken.isStringLiteral()) {
+                leave();
+                continue;
+            }
+            break;
+
         default:
             qWarning() << "Unhandled state" << m_currentState.top().type;
             break;
@@ -819,6 +826,9 @@ bool CodeFormatter::tryExpression(bool alsoExpression)
         break;
     }
 
+    if (m_currentToken.isStringLiteral())
+        newState = string_open;
+
     if (newState != -1) {
         if (alsoExpression)
             enter(expression);
@@ -1425,6 +1435,11 @@ void QtStyleCodeFormatter::onEnter(int newState, int *indentDepth, int *savedInd
     case cpp_macro_cont:
         *indentDepth = m_tabSettings.m_indentSize;
         break;
+
+    case string_open:
+        *indentDepth = tokenPosition;
+        *paddingDepth = 0;
+        break;
     }
 
     // ensure padding and indent are >= 0

src/plugins/cpptools/cppcodeformatter.h

@@ -180,7 +180,8 @@ public: // must be public to make Q_GADGET introspection work
         lambda_statement_expected,
         lambda_instroducer,              // when '=', '&' or ',' occurred within '[]'
         lambda_declarator,               // just after ']' when previous state is lambda_introducer
-        lambda_statement                 // just after '{' when previous state is lambda_declarator or lambda_declarator_or_expression
+        lambda_statement,                // just after '{' when previous state is lambda_declarator or lambda_declarator_or_expression
+        string_open
 
     };
     Q_ENUMS(StateType)