QT实现异步日志

#include <QCoreApplication>
#include <QDateTime>
#include <QDir>
#include <QFile>
#include <QProcess>
#include <QTextStream>
#include <QTimer>

#define ROLLSIZE 1000 * 1000 * 1000

const static int kRollPerSeconds_ = 60 * 60 * 24;

bool generateDirectorys(const QString &directory)
{
QDir sourceDir(directory);
if (sourceDir.exists())
return true;

QString tempDir;
QStringList directorys = directory.split("/");
for (int i = 0; i < directorys.count(); i++) {
QString path = directorys[i];
tempDir += path + "/";

QDir dir(tempDir);
if (!dir.exists() && !dir.mkdir(tempDir))
return false;
    }

return true;
}

struct FileUtilPrivate
{
QFile file;
//QTextStream 读写分离的，内部有缓冲区static const int QTEXTSTREAM_BUFFERSIZE = 16384;
QTextStream stream;
qint64 startTime = 0;
qint64 lastRoll = 0;
int count = 0;
qint64 autoDelFileDays = 30;
};

FileUtil::FileUtil(qint64 days, QObject *parent)
    : QObject(parent)
    , d_ptr(new FileUtilPrivate)
{
d_ptr->autoDelFileDays = days;
generateDirectorys(qApp->applicationDirPath() + "/log");
rollFile(0);
setTimer();
}

FileUtil::~FileUtil()
{
onFlush();
}

void FileUtil::onWrite(const QString &msg)
{
if (d_ptr->file.size() > ROLLSIZE) {
rollFile(++d_ptr->count);
    } else {
qint64 now = QDateTime::currentSecsSinceEpoch();
qint64 thisPeriod = now / kRollPerSeconds_ * kRollPerSeconds_;
if (thisPeriod != d_ptr->startTime) {
d_ptr->count = 0;
rollFile(0);
        }
    }

d_ptr->stream << msg;
}

void FileUtil::onFlush()
{
d_ptr->stream.flush();
}

QString FileUtil::getFileName(qint64 *now) const
{
*now = QDateTime::currentSecsSinceEpoch();
QString data = QDateTime::fromSecsSinceEpoch(*now).toString("yyyy-MM-dd-hh-mm-ss");
QString filename = QString("%1/log/%2.%3.%4.%5.log")
                           .arg(qApp->applicationDirPath(),
qAppName(),
data,
QSysInfo::machineHostName(),
QString::number(qApp->applicationPid()));
return filename;
}

bool FileUtil::rollFile(int count)
{
qint64 now = 0;
QString filename = getFileName(&now);
if (count) {
filename += QString(".%1").arg(count);
    } else {
autoDelFile();
    }
qint64 start = now / kRollPerSeconds_ * kRollPerSeconds_;
if (now > d_ptr->lastRoll) {
d_ptr->startTime = start;
d_ptr->lastRoll = now;
if (d_ptr->file.isOpen()) {
d_ptr->file.flush();
d_ptr->file.close();
        }
d_ptr->file.setFileName(filename);
d_ptr->file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Unbuffered);
d_ptr->stream.setDevice(&d_ptr->file);
fprintf(stderr, "%s\n", filename.toUtf8().constData());
return true;
    }
return false;
}

void FileUtil::autoDelFile()
{
const QString path(qApp->applicationDirPath() + "/log");
generateDirectorys(path);
QDir dir(path);

const QFileInfoList list = dir.entryInfoList(QDir::Files | QDir::NoDotAndDotDot, QDir::Time);
const QDateTime cur = QDateTime::currentDateTime();
const QDateTime pre = cur.addDays(-d_ptr->autoDelFileDays);

for (const QFileInfo &info : qAsConst(list)) {
if (info.lastModified() <= pre) {
dir.remove(info.fileName());
        }
    }
}

void FileUtil::setTimer()
{
QTimer *timer = new QTimer(this);
connect(timer, &QTimer::timeout, this, &FileUtil::onFlush);
timer->start(5000); // 5秒刷新一次
}