为什么在尝试提取单个文件时 SevenZipSharp.Interop NuGet 会提取多个文件？

Question

也许这只是我一个人，我做错了什么，或者这可能是课堂的预期结果，但我觉得有点不对劲……

我制作了以下测试存档（文件夹中也有文件，但不应与此问题相关）：

我使用以下方法提取单个文件（ New Text Document.txt ）...

#region SevenZipExtractor events
private void SevenZipExtractor_Extracting(object sender, ProgressEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZipExtractor_Extracting -- " + e.PercentDone + "%");

    m_progress.UpdateProcessingStatus(e.PercentDone);
}

private void SevenZipExtractor_FileExtractionFinished(object sender, FileInfoEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZipExtractor_FileExtractionFinished -- " + e.PercentDone + "% Filename:" + e.FileInfo.FileName);
}

private void SevenZipExtractor_FileExtractionStarted(object sender, FileInfoEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZipExtractor_FileExtractionStarted -- " + e.PercentDone + "% Filename:" + e.FileInfo.FileName);
}
#endregion

private void DecompressThread()
{
    using (SevenZipExtractor extractor = new SevenZipExtractor(inStream))
    {
        extractor.Extracting += SevenZipExtractor_Extracting;
        extractor.FileExtractionStarted += SevenZipExtractor_FileExtractionStarted;
        extractor.FileExtractionFinished += SevenZipExtractor_FileExtractionFinished;

        using (FileStream file = new FileStream("C:\Sandbox\Z-Test\New Text Document.txt", FileMode.Create, FileAccess.Write))
        {
            extractor.ExtractFile(4, file);
        }

        extractor.Extracting -= SevenZipExtractor_Extracting;
        extractor.FileExtractionStarted -= SevenZipExtractor_FileExtractionStarted;
        extractor.FileExtractionFinished -= SevenZipExtractor_FileExtractionFinished;
    }
}

然后随着事件Extracting 、 FileExtractionStarted和FileExtractionFinished我希望能得到以下结果......

SevenZipExtractor_FileExtractionStarted -- 100% Filename:New Text Document.txt
SevenZipExtractor_Extracting -- 100%
SevenZipExtractor_FileExtractionFinished -- 100% Filename:New Text Document.txt

但是，我得到以下结果......

SevenZipExtractor_Extracting -- 100%
SevenZipExtractor_Extracting -- 100%
SevenZipExtractor_FileExtractionStarted -- 20% Filename:Test Folder 1
SevenZipExtractor_FileExtractionFinished -- 20% Filename:Test Folder 1
SevenZipExtractor_FileExtractionStarted -- 40% Filename:Test Folder 2
SevenZipExtractor_FileExtractionFinished -- 40% Filename:Test Folder 2
SevenZipExtractor_FileExtractionStarted -- 60% Filename:Microsoft - Visual Studio 6 MSDN Library.iso
SevenZipExtractor_Extracting -- 1%
SevenZipExtractor_Extracting -- 2%
SevenZipExtractor_Extracting -- 3%
SevenZipExtractor_Extracting -- 4%
SevenZipExtractor_Extracting -- 5%
SevenZipExtractor_Extracting -- 6%
SevenZipExtractor_Extracting -- 7%
SevenZipExtractor_Extracting -- 8%
SevenZipExtractor_Extracting -- 9%
SevenZipExtractor_Extracting -- 10%
SevenZipExtractor_Extracting -- 11%
SevenZipExtractor_Extracting -- 12%
SevenZipExtractor_Extracting -- 13%
SevenZipExtractor_Extracting -- 14%
SevenZipExtractor_Extracting -- 15%
SevenZipExtractor_Extracting -- 16%
SevenZipExtractor_Extracting -- 17%
SevenZipExtractor_Extracting -- 18%
SevenZipExtractor_Extracting -- 19%
SevenZipExtractor_Extracting -- 20%
SevenZipExtractor_Extracting -- 21%
SevenZipExtractor_Extracting -- 22%
SevenZipExtractor_Extracting -- 23%
SevenZipExtractor_Extracting -- 24%
SevenZipExtractor_Extracting -- 25%
SevenZipExtractor_Extracting -- 26%
SevenZipExtractor_Extracting -- 27%
SevenZipExtractor_Extracting -- 28%
SevenZipExtractor_Extracting -- 29%
SevenZipExtractor_Extracting -- 30%
SevenZipExtractor_Extracting -- 31%
SevenZipExtractor_Extracting -- 32%
SevenZipExtractor_Extracting -- 33%
SevenZipExtractor_Extracting -- 34%
SevenZipExtractor_Extracting -- 35%
SevenZipExtractor_Extracting -- 36%
SevenZipExtractor_Extracting -- 37%
SevenZipExtractor_Extracting -- 38%
SevenZipExtractor_Extracting -- 39%
SevenZipExtractor_Extracting -- 40%
SevenZipExtractor_Extracting -- 41%
SevenZipExtractor_Extracting -- 42%
SevenZipExtractor_Extracting -- 43%
SevenZipExtractor_Extracting -- 44%
SevenZipExtractor_Extracting -- 45%
SevenZipExtractor_Extracting -- 46%
SevenZipExtractor_Extracting -- 47%
SevenZipExtractor_Extracting -- 48%
SevenZipExtractor_Extracting -- 49%
SevenZipExtractor_Extracting -- 50%
SevenZipExtractor_Extracting -- 51%
SevenZipExtractor_Extracting -- 52%
SevenZipExtractor_Extracting -- 53%
SevenZipExtractor_Extracting -- 54%
SevenZipExtractor_Extracting -- 55%
SevenZipExtractor_Extracting -- 56%
SevenZipExtractor_Extracting -- 57%
SevenZipExtractor_Extracting -- 58%
SevenZipExtractor_Extracting -- 59%
SevenZipExtractor_Extracting -- 60%
SevenZipExtractor_Extracting -- 61%
SevenZipExtractor_Extracting -- 62%
SevenZipExtractor_Extracting -- 63%
SevenZipExtractor_Extracting -- 64%
SevenZipExtractor_Extracting -- 65%
SevenZipExtractor_Extracting -- 66%
SevenZipExtractor_Extracting -- 67%
SevenZipExtractor_Extracting -- 68%
SevenZipExtractor_Extracting -- 69%
SevenZipExtractor_Extracting -- 70%
SevenZipExtractor_Extracting -- 71%
SevenZipExtractor_Extracting -- 72%
SevenZipExtractor_Extracting -- 73%
SevenZipExtractor_Extracting -- 74%
SevenZipExtractor_Extracting -- 75%
SevenZipExtractor_Extracting -- 76%
SevenZipExtractor_Extracting -- 77%
SevenZipExtractor_Extracting -- 78%
SevenZipExtractor_Extracting -- 79%
SevenZipExtractor_Extracting -- 80%
SevenZipExtractor_Extracting -- 81%
SevenZipExtractor_Extracting -- 82%
SevenZipExtractor_Extracting -- 83%
SevenZipExtractor_Extracting -- 84%
SevenZipExtractor_Extracting -- 85%
SevenZipExtractor_Extracting -- 86%
SevenZipExtractor_Extracting -- 87%
SevenZipExtractor_Extracting -- 88%
SevenZipExtractor_Extracting -- 89%
SevenZipExtractor_Extracting -- 90%
SevenZipExtractor_Extracting -- 91%
SevenZipExtractor_Extracting -- 92%
SevenZipExtractor_Extracting -- 93%
SevenZipExtractor_Extracting -- 94%
SevenZipExtractor_Extracting -- 95%
SevenZipExtractor_Extracting -- 96%
SevenZipExtractor_Extracting -- 97%
SevenZipExtractor_Extracting -- 98%
SevenZipExtractor_Extracting -- 99%
SevenZipExtractor_FileExtractionFinished -- 60% Filename:Microsoft - Visual Studio 6 MSDN Library.iso
SevenZipExtractor_FileExtractionStarted -- 80% Filename:New Microsoft Excel Worksheet.xlsx
SevenZipExtractor_FileExtractionFinished -- 80% Filename:New Microsoft Excel Worksheet.xlsx
SevenZipExtractor_FileExtractionStarted -- 100% Filename:New Text Document.txt
SevenZipExtractor_Extracting -- 100%
SevenZipExtractor_FileExtractionFinished -- 100% Filename:New Text Document.txt

似乎即使我试图提取单个文件，它也正在处理所有文件。 当我尝试更大规模地使用它时（提取整个文件而不是仅提取 1 个单个文件），我将拥有一个存档，其中根目录中有一个大文件和一堆小文件夹，并在尝试时看到巨大的影响处理每个小文件（提取每个小文件所需的时间与提取存档根目录下的大文件所需的时间一样长。

用户是否有某种期望在内存流中设置搜索点？ 我怎样才能不花这么长时间提取一个小文本文件？

Answer 1

我已经向GitHub repo提交了一个 问题。 在这一点上，我认为这要么是过去未解决的错误，要么是一次提取单个文件并不是提取整个存档的预期方法。 在我的问题示例中，我的目标是尝试从存档中提取单个文件，而不用类处理整个文件（即使它最终只提取单个文件）。

在宏伟的计划中，我试图手动提取一次处理一个文件的整个存档（主要是因为我从引用的事件中获得的消息没有给我可靠的结果，例如一次只处理一个文件）。 这可能不是提取档案的预期方法（也许只是另一种最终得到相同结果但从未使用过所以从未抱怨过的方法）。

我最终尝试使用以下方法成功提取整个存档。 从上述事件中获取非常可靠的消息。 我还在这个示例中添加了更多内容（然后是我的问题中的内容）以使其完全运行代码。 我错误地遗漏了问题中的inStream引用。

#region SevenZipExtractor events
private void SevenZip_Processing(object sender, ProgressEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZip_Processing -- " + e.PercentDone + "%");

    m_progress.UpdateProcessingStatus(e.PercentDone);
}

private void SevenZipExtractor_FileExtractionFinished(object sender, FileInfoEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZipExtractor_FileExtractionFinished -- " + e.PercentDone + "% Filename:" + e.FileInfo.FileName);
}

private void SevenZipExtractor_FileExtractionStarted(object sender, FileInfoEventArgs e)
{
    System.Diagnostics.Debug.WriteLine("SevenZipExtractor_FileExtractionStarted -- " + e.PercentDone + "% Filename:" + e.FileInfo.FileName);
}
#endregion

private void DecompressThread(string archiveFilePath)
{
    byte[] fileInBytes = File.ReadAllBytes(archiveFilePath);

    using (MemoryStream inStream = new MemoryStream(fileInBytes))
    {
        using (SevenZipExtractor extractor = new SevenZipExtractor(inStream))
        {
            extractor.Extracting += SevenZip_Processing;
            extractor.FileExtractionStarted += SevenZipExtractor_FileExtractionStarted;
            extractor.FileExtractionFinished += SevenZipExtractor_FileExtractionFinished;

            extractor.ExtractArchive("C:\Sandbox\Z-Test");

            extractor.Extracting -= SevenZip_Processing;
            extractor.FileExtractionStarted -= SevenZipExtractor_FileExtractionStarted;
            extractor.FileExtractionFinished -= SevenZipExtractor_FileExtractionFinished;
        }
    }
}

结果是……

SevenZipExtractor_FileExtractionStarted -- 11% Filename:Test Folder 1
SevenZipExtractor_FileExtractionFinished -- 11% Filename:Test Folder 1
SevenZipExtractor_FileExtractionStarted -- 22% Filename:Test Folder 2
SevenZipExtractor_FileExtractionFinished -- 22% Filename:Test Folder 2
SevenZipExtractor_FileExtractionStarted -- 33% Filename:Microsoft - Visual Studio 6 MSDN Library.iso
SevenZip_Processing -- 20%
SevenZip_Processing -- 40%
SevenZip_Processing -- 60%
SevenZip_Processing -- 80%
SevenZipExtractor_FileExtractionFinished -- 33% Filename:Microsoft - Visual Studio 6 MSDN Library.iso
SevenZipExtractor_FileExtractionStarted -- 44% Filename:New Microsoft Excel Worksheet.xlsx
SevenZipExtractor_FileExtractionFinished -- 44% Filename:New Microsoft Excel Worksheet.xlsx
SevenZipExtractor_FileExtractionStarted -- 56% Filename:New Text Document.txt
SevenZipExtractor_FileExtractionFinished -- 56% Filename:New Text Document.txt
SevenZipExtractor_FileExtractionStarted -- 67% Filename:Test Folder 1\New Text Document In TF1 - Copy.txt
SevenZipExtractor_FileExtractionFinished -- 67% Filename:Test Folder 1\New Text Document In TF1 - Copy.txt
SevenZipExtractor_FileExtractionStarted -- 78% Filename:Test Folder 1\New Text Document In TF1.txt
SevenZipExtractor_FileExtractionFinished -- 78% Filename:Test Folder 1\New Text Document In TF1.txt
SevenZipExtractor_FileExtractionStarted -- 89% Filename:Test Folder 2\New Text Document In TF2 - Copy.txt
SevenZipExtractor_FileExtractionFinished -- 89% Filename:Test Folder 2\New Text Document In TF2 - Copy.txt
SevenZipExtractor_FileExtractionStarted -- 100% Filename:Test Folder 2\New Text Document In TF2.txt
SevenZip_Processing -- 100%
SevenZipExtractor_FileExtractionFinished -- 100% Filename:Test Folder 2\New Text Document In TF2.txt

Answer 2

我是另一个 SevenZipSharp fork 的作者，终于有时间看看你的问题。 仅尝试提取一个文件时，您会收到如此多的文件提取事件，这是因为7z 档案是使用Solid compression创建的。

当您尝试从实体存档中提取单个文件时，解压缩从文件的开头开始，并通过它直到找到您要查找的文件。 您的存档是最坏的情况，您要查找的文件位于存档的末尾（您的结果显示“New Text Document.txt”最后被提取）。

您的问题的解决方案取决于您最终需要实现的目标，以及您对创建档案的权力。 如果您只需要提取一个文件，并且可以更改存档格式，我的目标是某种不使用可靠压缩的格式（例如 zip）。 如果您被迫使用 7z 文件，并且需要使用多个文件，最好的方法可能是将它们全部提取到一个临时目录并在那里处理它们。