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在我的服务器应用程序中，我正在创建一个大小为 5kb 的日志文件。如果我超过 5 kb 的文件大小，我必须在新内容的帮助下覆盖旧内容。如果您有任何想法，请与我分享。

我还需要在qt中实现这种技术。

我在 c++ 中找到了一些示例，但是使用我不熟悉的 boost 库，你能帮我在 qt 中实现吗？

std::ostream & libLogging::FileRotationLogSink::GetCurrentStream( 
    std::string::size_type required )
{
    if ( static_cast<std::string::size_type>(m_CurrentStream.tellp( )) + 
        required > m_Limit ) {
        m_CurrentStream.close();
        // remove old backup
        if ( boost::filesystem::exists( m_BackupPath ) ) {
            boost::filesystem::remove( m_BackupPath );
        }
        // backup current logfile
        boost::filesystem::rename( m_LogFilePath, m_BackupPath );
        // open new logfile
        m_CurrentStream.open( m_LogFilePath );
    }
    return m_CurrentStream;
}
4

2 回答 2

1

示例实现：

#ifndef FILEROTATIONLOGSINK_H
#define FILEROTATIONLOGSINK_H

#include <QFile>
#include <QTextStream>

namespace libLogging {

class FileRotationLogSink
{
public:

    explicit FileRotationLogSink(size_t Limit = 5 * (1 << 10));
    QTextStream &GetCurrentStream(size_t required = 0);

private:

    size_t m_Limit;
    QString m_LogFilePath, m_BackupPath;
    QTextStream m_CurrentStream;
    QFile m_File;

    void openStream();
};
}

#endif // FILEROTATIONLOGSINK_H

与相关cpp

#include "FileRotationLogSink.h"

libLogging::FileRotationLogSink::FileRotationLogSink(size_t Limit) :
    m_Limit(Limit),
    m_LogFilePath("log"),
    m_BackupPath("bak")
{
    m_File.setFileName(m_LogFilePath);
    m_File.open(QIODevice::WriteOnly | QIODevice::Text);
    m_CurrentStream.setDevice(&m_File);
}

QTextStream& libLogging::FileRotationLogSink::GetCurrentStream(size_t required) {

    if (m_File.size() + required > m_Limit) {
        m_File.flush();
        m_File.close();

        // remove old backup
        if (QFile::exists(m_BackupPath))
            QFile::remove(m_BackupPath);

        // backup current logfile
        QFile::rename(m_LogFilePath, m_BackupPath);
        m_File.open(QIODevice::WriteOnly | QIODevice::Text);
    }

    return m_CurrentStream;
}

示例使用：

#include "mainwindow.h"
#include "FileRotationLogSink.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    libLogging::FileRotationLogSink log(100);
    for (int i = 0; i < 100; ++i)
        log.GetCurrentStream() << "line " << i << endl;
}

对数产量

line 92
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在bak

line 79
line 80
line 81
line 82
line 83
line 84
line 85
line 86
line 87
line 88
line 89
line 90
line 91
于 2013-08-10T07:06:08.107 回答
0

您可以将 替换boost::filesystem::<functions>为QFile::<functions>。检查文档以查看用法和确切的签名。

于 2013-08-10T05:17:12.303 回答