Privately introducing QDecompressHelper for network purposes

To support streaming decompression in QNAM.
Will also be used to refactor existing decompression code in QNAM.

Task-number: QTBUG-83269
Change-Id: Iecf3e359734163f15686c949f75d41fa4794a00e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 118 insertions, 0 deletions

diff --git a/src/network/access/qdecompresshelper_p.h b/src/network/access/qdecompresshelper_p.h
new file mode 100644
index 0000000000..5252925862
--- /dev/null
+++ b/src/network/access/qdecompresshelper_p.h
@@ -0,0 +1,118 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtNetwork module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef DECOMPRESS_HELPER_P_H
+#define DECOMPRESS_HELPER_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API. It exists for the convenience
+// of the Network Access API. This header file may change from
+// version to version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtNetwork/private/qtnetworkglobal_p.h>
+#include <QtCore/private/qbytedata_p.h>
+
+#include <memory>
+
+QT_BEGIN_NAMESPACE
+
+class QIODevice;
+class Q_AUTOTEST_EXPORT QDecompressHelper
+{
+public:
+    enum ContentEncoding {
+        None,
+        Deflate,
+        GZip,
+    };
+
+    QDecompressHelper() = default;
+    ~QDecompressHelper();
+
+    bool setEncoding(const QByteArray &contentEncoding);
+
+    bool isCountingBytes() const;
+    void setCountingBytesEnabled(bool shouldCount);
+
+    qint64 uncompressedSize() const;
+
+    bool hasData() const;
+    void feed(const QByteArray &data);
+    void feed(QByteArray &&data);
+    void feed(const QByteDataBuffer &buffer);
+    void feed(QByteDataBuffer &&buffer);
+    qsizetype read(char *data, qsizetype maxSize);
+
+    bool isValid() const;
+
+    void clear();
+
+    static bool isSupportedEncoding(const QByteArray &encoding);
+
+private:
+    bool countInternal();
+    bool countInternal(const QByteArray &data);
+    bool countInternal(const QByteDataBuffer &buffer);
+
+    bool setEncoding(ContentEncoding ce);
+    qint64 encodedBytesAvailable() const;
+
+    qsizetype readZLib(char *data, qsizetype maxSize);
+
+    QByteDataBuffer compressedDataBuffer;
+    bool decoderHasData = false;
+
+    bool countDecompressed = false;
+    std::unique_ptr<QDecompressHelper> countHelper;
+    qint64 uncompressedBytes = 0;
+
+    ContentEncoding contentEncoding = None;
+
+    void *decoderPointer = nullptr;
+};
+
+QT_END_NAMESPACE
+
+#endif // DECOMPRESS_HELPER_P_H