Properly escape bytearray data outside the ascii range when using a codec

Some codecs can't handle the range outside ascii properly and would then
fail to read the data back in correctly.

Backport of change 7df8b1ada4b23acedda5724b492c26a8e322648b from Qt 5.

Task-number: QTBUG-15543
Change-Id: I4c02921e787a939eeec0c7a11603b5896d756aef
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 28 insertions, 2 deletions

diff --git a/src/corelib/io/qsettings.cpp b/src/corelib/io/qsettings.cpp
index bcd14a57bb..2f62e8fc27 100644
--- a/src/corelib/io/qsettings.cpp
+++ b/src/corelib/io/qsettings.cpp
@@ -680,6 +680,9 @@ void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result,
 {
     bool needsQuotes = false;
     bool escapeNextIfDigit = false;
+    bool useCodec = codec && !str.startsWith(QLatin1String("@ByteArray("))
+                    && !str.startsWith(QLatin1String("@Variant("));
+
     int i;
     int startPos = result.size();
 
@@ -732,12 +735,12 @@ void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result,
             result += (char)ch;
             break;
         default:
-            if (ch <= 0x1F || (ch >= 0x7F && !codec)) {
+            if (ch <= 0x1F || (ch >= 0x7F && !useCodec)) {
                 result += "\\x";
                 result += QByteArray::number(ch, 16);
                 escapeNextIfDigit = true;
 #ifndef QT_NO_TEXTCODEC
-            } else if (codec) {
+            } else if (useCodec) {
                 // slow
                 result += codec->fromUnicode(str.at(i));
 #endif
diff --git a/tests/auto/qsettings/tst_qsettings.cpp b/tests/auto/qsettings/tst_qsettings.cpp
index 379d193338..86e1866cf0 100644
--- a/tests/auto/qsettings/tst_qsettings.cpp
+++ b/tests/auto/qsettings/tst_qsettings.cpp
@@ -185,6 +185,7 @@ private slots:
 
     void testByteArray_data();
     void testByteArray();
+    void iniCodec();
 
 private:
     void oldWriteEntry_data();
@@ -718,6 +719,28 @@ void tst_QSettings::testByteArray()
     }
 }
 
+void tst_QSettings::iniCodec()
+{
+    {
+        QSettings settings("QtProject", "tst_qsettings");
+        settings.setIniCodec("cp1251");
+        QByteArray ba;
+        ba.resize(256);
+        for (int i = 0; i < ba.size(); i++)
+            ba[i] = i;
+        settings.setValue("array",ba);
+    }
+    {
+        QSettings settings("QtProject", "tst_qsettings");
+        settings.setIniCodec("cp1251");
+        QByteArray ba = settings.value("array").toByteArray();
+        QCOMPARE(ba.size(), 256);
+        for (int i = 0; i < ba.size(); i++)
+            QCOMPARE((uchar)ba.at(i), (uchar)i);
+    }
+
+}
+
 void tst_QSettings::testErrorHandling_data()
 {
     QTest::addColumn<int>("filePerms"); // -1 means file should not exist