Add support for 8bit encodings not ASCII compatible in QXMLStreamWriter.

When using a 8 bit encoding to write a file, a test discovers if the
encoding is really ASCII compatible by examining a letter and one of the
XML reserved characters. EBCDIC, in the current base, was not well
handled.

[ChangeLog][QtCore][QXmlStreamWriter] Fixed a bug that prevented the
generation of valid XML files when using encoding with 8 bit per
character but not ASCII compatible. QXMLStreamWriter generated XML
markup using always ASCII in this case.

Change-Id: I9c86a122dd91b2290d50c358638442f99777d4ae
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 47 insertions, 4 deletions

diff --git a/src/corelib/xml/qxmlstream.cpp b/src/corelib/xml/qxmlstream.cpp
index 64a130e45a..a235145669 100644
--- a/src/corelib/xml/qxmlstream.cpp
+++ b/src/corelib/xml/qxmlstream.cpp
@@ -3019,10 +3019,14 @@ void QXmlStreamWriterPrivate::checkIfASCIICompatibleCodec()
 {
 #ifndef QT_NO_TEXTCODEC
     Q_ASSERT(encoder);
-    // assumes ASCII-compatibility for all 8-bit encodings
-    QChar space = QLatin1Char(' ');
-    const QByteArray bytes = encoder->fromUnicode(&space, 1);
-    isCodecASCIICompatible = (bytes.count() == 1);
+    // test ASCII-compatibility using the letter 'a'
+    QChar letterA = QLatin1Char('a');
+    const QByteArray bytesA = encoder->fromUnicode(&letterA, 1);
+    const bool isCodecASCIICompatibleA = (bytesA.count() == 1) && (bytesA[0] == 0x61) ;
+    QChar letterLess = QLatin1Char('<');
+    const QByteArray bytesLess = encoder->fromUnicode(&letterLess, 1);
+    const bool isCodecASCIICompatibleLess = (bytesLess.count() == 1) && (bytesLess[0] == 0x3C) ;
+    isCodecASCIICompatible = isCodecASCIICompatibleA && isCodecASCIICompatibleLess ;
 #else
     isCodecASCIICompatible = true;
 #endif
diff --git a/tests/auto/corelib/xml/qxmlstream/tst_qxmlstream.cpp b/tests/auto/corelib/xml/qxmlstream/tst_qxmlstream.cpp
index 1da29ac3bd..b0fd1187f5 100644
--- a/tests/auto/corelib/xml/qxmlstream/tst_qxmlstream.cpp
+++ b/tests/auto/corelib/xml/qxmlstream/tst_qxmlstream.cpp
@@ -561,6 +561,7 @@ private slots:
     void checkCommentIndentation() const;
     void checkCommentIndentation_data() const;
     void crashInXmlStreamReader() const;
+    void write8bitCodec() const;
     void hasError() const;
 
 private:
@@ -1578,5 +1579,43 @@ void tst_QXmlStream::hasError() const
 
 }
 
+void tst_QXmlStream::write8bitCodec() const
+{
+    QBuffer outBuffer;
+    QVERIFY(outBuffer.open(QIODevice::WriteOnly));
+    QXmlStreamWriter writer(&outBuffer);
+    writer.setAutoFormatting(false);
+
+    QTextCodec *codec = QTextCodec::codecForName("IBM500");
+    if (!codec) {
+        QSKIP("Encoding IBM500 not available.");
+    }
+    writer.setCodec(codec);
+
+    writer.writeStartDocument();
+    writer.writeStartElement("root");
+    writer.writeAttribute("attrib", "1");
+    writer.writeEndElement();
+    writer.writeEndDocument();
+    outBuffer.close();
+
+    // test 8 bit encoding
+    QByteArray values = outBuffer.data();
+    QVERIFY(values.size() > 1);
+    // check '<'
+    QCOMPARE(values[0] & 0x00FF, 0x4c);
+    // check '?'
+    QCOMPARE(values[1] & 0x00FF, 0x6F);
+
+    // convert the start of the XML
+    const QString expected = ("<?xml version=\"1.0\" encoding=\"IBM500\"?>");
+    QTextDecoder *decoder = codec->makeDecoder();
+    QVERIFY(decoder);
+    QString decodedText = decoder->toUnicode(values);
+    delete decoder;
+    QVERIFY(decodedText.startsWith(expected));
+}
+
+
 #include "tst_qxmlstream.moc"
 // vim: et:ts=4:sw=4:sts=4