add fileutils: classes for error-checked reading and writing of files

the internal use of SaveFile ensures that we don't leave truncated
pre-existing files behind if the disk is full or something else bad
happens.

Task-number: QTCREATORBUG-1619

src/libs/utils/fileutils.h

@@ -0,0 +1,133 @@
+/**************************************************************************
+**
+** This file is part of Qt Creator
+**
+** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
+**
+** Contact: Nokia Corporation (info@qt.nokia.com)
+**
+**
+** GNU Lesser General Public License Usage
+**
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this file.
+** Please review the following information to ensure the GNU Lesser General
+** Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** Other Usage
+**
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**************************************************************************/
+
+#ifndef FILEUTILS_H
+#define FILEUTILS_H
+
+#include "utils_global.h"
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QIODevice>
+
+QT_BEGIN_NAMESPACE
+class QFile;
+class QTemporaryFile;
+class QWidget;
+class QTextStream;
+class QDataStream;
+class QXmlStreamWriter;
+QT_END_NAMESPACE
+
+namespace Utils {
+
+class QTCREATOR_UTILS_EXPORT FileReader
+{
+    Q_DECLARE_TR_FUNCTIONS(FileUtils) // sic!
+public:
+    static QByteArray fetchQrc(const QString &fileName); // Only for internal resources
+    bool fetch(const QString &fileName, QIODevice::OpenMode mode = QIODevice::NotOpen); // QIODevice::ReadOnly is implicit
+    bool fetch(const QString &fileName, QIODevice::OpenMode mode, QString *errorString);
+    bool fetch(const QString &fileName, QString *errorString)
+        { return fetch(fileName, QIODevice::NotOpen, errorString); }
+    bool fetch(const QString &fileName, QIODevice::OpenMode mode, QWidget *parent);
+    bool fetch(const QString &fileName, QWidget *parent)
+        { return fetch(fileName, QIODevice::NotOpen, parent); }
+    const QByteArray &data() const { return m_data; }
+    const QString &errorString() const { return m_errorString; }
+private:
+    QByteArray m_data;
+    QString m_errorString;
+};
+
+class QTCREATOR_UTILS_EXPORT FileSaverBase
+{
+    Q_DECLARE_TR_FUNCTIONS(FileUtils) // sic!
+public:
+    FileSaverBase();
+    virtual ~FileSaverBase();
+
+    QString fileName() const { return m_fileName; }
+    bool hasError() const { return m_hasError; }
+    QString errorString() const { return m_errorString; }
+    virtual bool finalize();
+    bool finalize(QString *errStr);
+    bool finalize(QWidget *parent);
+
+    bool write(const char *data, int len);
+    bool write(const QByteArray &bytes);
+    bool setResult(QTextStream *stream);
+    bool setResult(QDataStream *stream);
+    bool setResult(QXmlStreamWriter *stream);
+    bool setResult(bool ok);
+
+protected:
+    QFile *m_file;
+    QString m_fileName;
+    QString m_errorString;
+    bool m_hasError;
+
+private:
+    Q_DISABLE_COPY(FileSaverBase)
+};
+
+class QTCREATOR_UTILS_EXPORT FileSaver : public FileSaverBase
+{
+public:
+    explicit FileSaver(const QString &filename, QIODevice::OpenMode mode = QIODevice::NotOpen); // QIODevice::WriteOnly is implicit
+
+    virtual bool finalize();
+    using FileSaverBase::finalize;
+    QFile *file() { return m_file; }
+
+private:
+    Q_DISABLE_COPY(FileSaver)
+    bool m_isSafe;
+};
+
+class QTCREATOR_UTILS_EXPORT TempFileSaver : public FileSaverBase
+{
+public:
+    explicit TempFileSaver(const QString &templ = QString());
+    ~TempFileSaver();
+
+    QTemporaryFile *file() { return reinterpret_cast<QTemporaryFile *>(m_file); }
+
+    void setAutoRemove(bool on) { m_autoRemove = on; }
+
+private:
+    Q_DISABLE_COPY(TempFileSaver)
+    bool m_autoRemove;
+};
+
+}
+
+#endif // FILEUTILS_H