CPlusPlus: Fix finding end of raw string literal

The employed algorithm lacked proper backtracking, potentially causing us
to miss the delimiter altogether.

Change-Id: I7993c3c27d034925bd884e192779c85c54be9ec4
Reviewed-by: hjk <hjk@qt.io>

3 files changed, 18 insertions, 9 deletions

diff --git a/src/libs/3rdparty/cplusplus/Lexer.cpp b/src/libs/3rdparty/cplusplus/Lexer.cpp
index deafe432b6..62a95f455a 100644
--- a/src/libs/3rdparty/cplusplus/Lexer.cpp
+++ b/src/libs/3rdparty/cplusplus/Lexer.cpp
@@ -838,16 +838,16 @@ void Lexer::scanRawStringLiteral(Token *tok, unsigned char hint)
 
 bool Lexer::scanUntilRawStringLiteralEndPrecise()
 {
-    int matchLen = 0;
+    QByteArray slidingWindow;
+    slidingWindow.reserve(_expectedRawStringSuffix.size());
     while (_yychar) {
-        if (_yychar == _expectedRawStringSuffix.at(matchLen)) {
-            if (++matchLen == _expectedRawStringSuffix.length()) {
-                _expectedRawStringSuffix.clear();
-                yyinp();
-                return true;
-            }
-        } else {
-            matchLen = 0;
+        slidingWindow.append(_yychar);
+        if (slidingWindow.size() > _expectedRawStringSuffix.size())
+            slidingWindow.removeFirst();
+        if (slidingWindow == _expectedRawStringSuffix) {
+            _expectedRawStringSuffix.clear();
+            yyinp();
+            return true;
         }
         yyinp();
     }
diff --git a/src/plugins/cppeditor/cpphighlighter.cpp b/src/plugins/cppeditor/cpphighlighter.cpp
index f562d9afec..142b2b296c 100644
--- a/src/plugins/cppeditor/cpphighlighter.cpp
+++ b/src/plugins/cppeditor/cpphighlighter.cpp
@@ -590,6 +590,12 @@ void CppHighlighterTest::test_data()
         << 38 << 18 << 39 << 3 << C_STRING;
     QTest::newRow("multi-line user-defined UTF-16 string literal (suffix)")
         << 39 << 4 << 39 << 5 << C_OPERATOR;
+    QTest::newRow("multi-line raw string literal with consecutive closing parens (prefix)")
+        << 48 << 18 << 48 << 20 << C_KEYWORD;
+    QTest::newRow("multi-line raw string literal with consecutive closing parens (content)")
+        << 49 << 1 << 49 << 1 << C_STRING;
+    QTest::newRow("multi-line raw string literal with consecutive closing parens (suffix)")
+        << 49 << 2 << 49 << 3 << C_KEYWORD;
 }
 
 void CppHighlighterTest::test()
diff --git a/src/plugins/cppeditor/testcases/highlightingtestcase.cpp b/src/plugins/cppeditor/testcases/highlightingtestcase.cpp
index d1ec061aa2..a9102ce457 100644
--- a/src/plugins/cppeditor/testcases/highlightingtestcase.cpp
+++ b/src/plugins/cppeditor/testcases/highlightingtestcase.cpp
@@ -44,3 +44,6 @@ static void parenTest()
         /* comment */ \
     } while (false);
 }
+
+const char* s7 = R"(
+))";