Global regexp search would eat all memory for matched empty lines.

E.g. for '^$'. also for '.*'

Task-number: QTCREATORBUG-4443
Change-Id: Ic164361ccdf791c2d0ec3c6ec501e34c9ec3fda6
Reviewed-on: http://codereview.qt.nokia.com/681

Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>

src/libs/utils/filesearch.cpp

@@ -245,13 +245,18 @@ void runFileSearchRegExp(QFutureInterface<FileSearchResultList> &future,
         QString line;
         while (!stream.atEnd()) {
             line = stream.readLine();
+            int lengthOfLine = line.size();
             int pos = 0;
             while ((pos = expression.indexIn(line, pos)) != -1) {
                 results << FileSearchResult(s, lineNr, line,
                                               pos, expression.matchedLength(),
                                               expression.capturedTexts());
                 ++numMatches;
+                if (expression.matchedLength() == 0)
+                    break;
                 pos += expression.matchedLength();
+                if (pos >= lengthOfLine)
+                    break;
             }
             ++lineNr;
         }