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c++ - 将复制文件的 QDateTime 调整为源文件的 QDateTime

问题描述

语境：

我有一个应用程序可以搜索目录中的文件并复制特定文件。

问题：

使用FileCopyExW，我成功地将文件复制到新位置，但是文件的日期和时间不匹配，它可能会偏离一秒或更长时间，如下例所示。

尝试QDateTime用源文件（有时）修改覆盖目标文件无法写入正确的日期，如下面的示例所示。

调试器截图

在此处输入图像描述

此文件的日志输出

09:34:50.731 Warning: File times do not match
09:34:50.731 Warning: Birth time differene:  0
09:34:50.731 Warning: Last Access time differene:  483
09:42:02.660 Warning: Last Modified time differene:  483
09:42:02.660 Debug:

失败的随机其他文件的输出

09:43:48.831 Warning: File times do not match
09:43:48.831 Warning: Birth time differene:  -7
09:43:48.831 Warning: Last Access time differene:  1462
09:44:53.602 Warning: Last Modified time differene:  0
09:44:53.602 Debug:

任何想法为什么会发生这种情况以及我该如何解决？

代码示例：

 // File copied successfully at this point, now adjust file times as these may not be accurate (why?)

 QFile newFile(destination);
 if (newFile.open(QIODevice::OpenModeFlag::WriteOnly | QIODevice::OpenModeFlag::Append)) {

      // set file attributes, create, last write and last modified dates the same as original file
      QFileInfo srcFi(storageFile.location);

      // Set last modified date - most important
      QDateTime localLastModified = srcFi.lastModified().toLocalTime();
      if (!newFile.setFileTime(localLastModified, QFileDevice::FileModificationTime)) {
           printWarningFileError(TAG, QString("Failed to set lastModified date for file at [%1]").arg(destination), &newFile);
      }

      // Set last accessed date
      QDateTime localLastRead = srcFi.lastRead().toLocalTime();
      if (!newFile.setFileTime(localLastRead, QFileDevice::FileAccessTime)) {
           printWarningFileError(TAG, QString("Failed to set lastAccessed date for file at [%1]").arg(destination), &newFile);
      }

      // Set created date
      QDateTime localBirthTime = srcFi.birthTime().toLocalTime();
      if (!newFile.setFileTime(localBirthTime, QFileDevice::FileBirthTime)) {
           printWarningFileError(TAG, QString("Failed to set created date for file at [%1]").arg(destination), &newFile);
      }

      // Ensure we write out content before closing file (not really necessary due to close() )
      newFile.flush();
      newFile.close();

      // Read file & refresh meta data for checking
      QFileInfo fiDest(destination);
      fiDest.refresh();

      // Read destination file date data
      QDateTime destFileBirth = fiDest.birthTime();
      QDateTime destFileAccess = fiDest.lastRead();
      QDateTime destFileModified = fiDest.lastModified();

      // Compare dates
      bool birthTimeMatch = (destFileBirth != localBirthTime);
      bool accessTimeMatch = (destFileAccess != localLastRead);
      bool modifiedTimeMatch = (destFileModified != localLastModified);

      if (!(birthTimeMatch && accessTimeMatch && modifiedTimeMatch)) {
           qWarning() << "File times do not match";
           qWarning() << "Birth time differene: " << (destFileBirth.toMSecsSinceEpoch() - localBirthTime.toMSecsSinceEpoch());
           qWarning() << "Last Access time differene: " << (destFileAccess.toMSecsSinceEpoch() - localLastRead.toMSecsSinceEpoch());
           qWarning() << "Last Modified time differene: " << (destFileModified.toMSecsSinceEpoch() - localLastModified.toMSecsSinceEpoch());
           qDebug() << "";
      }
      else {
           qDebug() << "All good";
      }
 }
 else {
      printWarningFileError(TAG, QString("Failed to open file for adjust dates [%1]").arg(destination), &newFile);
 }

标签： c++qtwinapiqfileqfileinfo

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