fix(compressor): fix MIME type detection failure for spanned ZIP files

[dengzhongyuan365-dev]

• Some spanned ZIP files start with PK\x07\x08 signature (non-standard PK\x03\x04), which Qt MIME detection cannot recognize
• When file extension is .zip but content detection returns non-ZIP type, fall back to file command for re-detection

Qt 无法识别以 PK\x07\x08 开头的分卷 ZIP 文件，当扩展名为 .zip
但内容检测结果非 ZIP 类型时，回退使用 file 命令二次检测以确保
正确识别。

PMS: ztgd2026060900011

Influence: spanned ZIP files can be correctly detected and extracted

Summary by Sourcery

Bug Fixes:

• Ensure spanned ZIP files with non-standard signatures are correctly detected by falling back to the file command when Qt content detection is inconclusive or inconsistent with a .zip extension.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adjusts MIME type detection logic to better handle ZIP files, particularly WinZip-style spanned ZIPs, by refining when the system falls back to the file command.

Flow diagram for updated ZIP MIME detection fallback logic

flowchart TD
    A[determineMimeType filename] --> B[mimeFromExtension]
    B --> C[extName = mimeFromExtension.name]
    C --> D[isZipExtension = extName == application/zip]
    D --> E[mimeFromContent]
    E --> F[isContentZip = mimeFromContent.inherits application/zip]
    F --> G["needFileCommandFallback = mimeFromContent.isDefault OR (isZipExtension AND NOT isContentZip)"]
    G -->|true| H[Run file command for detection]
    G -->|false| I[Use mimeFromContent]
    H --> J[Return MIME type]
    I --> J

Loading

File-Level Changes

Change	Details	Files
Refine MIME detection fallback logic to use the file command when ZIP extensions conflict with non-ZIP content detection.	Introduce extName, isZipExtension, and isContentZip variables derived from existing MIME detection results. Define needFileCommandFallback to be true when content detection is default or when a .zip extension is present but content is not recognized as ZIP. Reuse the existing file-command-based detection path, now guarded by the new needFileCommandFallback condition instead of only checking mimeFromContent.isDefault().	src/source/common/mimetypes.cpp

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[sourcery-ai]

Hey - I've left some high level feedback:

• Binding mimeFromExtension.name() to const QString &extName creates a dangling reference because name() returns a temporary; store it by value (QString extName = mimeFromExtension.name();) instead.
• Since the string literal "application/zip" is used in multiple places, consider extracting it into a constexpr/constant or reusing the same QStringLiteral to avoid duplication and keep type checks consistent.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Binding `mimeFromExtension.name()` to `const QString &extName` creates a dangling reference because `name()` returns a temporary; store it by value (`QString extName = mimeFromExtension.name();`) instead.
- Since the string literal `"application/zip"` is used in multiple places, consider extracting it into a constexpr/constant or reusing the same QStringLiteral to avoid duplication and keep type checks consistent.

---

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[deepin-ci-robot]

deepin pr auto review

我对这段代码的改进意见如下：

1. 代码逻辑改进：

• 当前的改进增加了对ZIP文件的特殊处理逻辑，这是一个很好的优化，可以处理WinZip分卷ZIP等特殊情况。
• 使用明确的布尔变量(isZipExtension, isContentZip, needFileCommandFallback)提高了代码的可读性。

2. 代码质量改进：

• 建议将magic number(如"application/zip")定义为常量或枚举，以提高代码的可维护性。
• 可以考虑将这部分逻辑封装为一个单独的函数，以提高代码的模块化和可重用性。

3. 代码性能改进：

• 当前代码在每次调用时都会创建QProcess对象，可以考虑将其作为类成员变量以避免重复创建。
• 对于频繁调用的场景，可以考虑添加缓存机制，避免重复检测相同文件的MIME类型。

4. 代码安全改进：

• 在使用QProcess执行外部命令时，应该添加错误处理机制，确保命令执行失败时能够优雅地处理。
• 应该限制可执行的file命令的参数，避免命令注入风险。

5. 其他建议：

• 建议添加注释说明为什么需要特殊处理ZIP文件，以便后续维护者理解这段代码的意图。
• 考虑添加日志记录，记录MIME类型检测的决策过程，便于调试和问题追踪。

改进后的代码示例：

// 定义MIME类型常量
namespace {
    const QString APPLICATION_ZIP = QStringLiteral("application/zip");
}

// 将检测逻辑封装为单独的函数
bool shouldUseFileCommandFallback(const QString& mimeContent, const QString& mimeExtension) {
    bool isZipExtension = (mimeExtension == APPLICATION_ZIP);
    bool isContentZip = mimeContent.inherits(APPLICATION_ZIP);
    return mimeContent.isDefault() || (isZipExtension && !isContentZip);
}

CustomMimeType determineMimeType(const QString &filename) {
    // ... 前面的代码 ...
    
    const QString &extName = mimeFromExtension.name();
    if (shouldUseFileCommandFallback(mimeFromContent, extName)) {
        qDebug() << "Using file command to detect MIME type for:" << filename;
        QProcess process;
        QStringList args;
        // ... 后面的代码 ...
        
        // 添加错误处理
        if (!process.waitForFinished()) {
            qWarning() << "File command execution failed:" << process.errorString();
            return mimeFromExtension; // 或其他适当的错误处理
        }
        // ... 其余代码 ...
    }
    // ... 其余代码 ...
}

这些改进可以提高代码的可维护性、性能和安全性，同时保持原有功能的完整性。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: dengzhongyuan365-dev, lzwind

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• debian/deepin/OWNERS

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[dengzhongyuan365-dev]

/forcemerge