fix: [sdlplayer] enhance pointer validation

[LiHua000]

Log: as title

Summary by Sourcery

Bug Fixes:

• Prevent crashes in SDL audio setup callback by checking for null data and player pointers before dereferencing.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adds defensive pointer validation in SdlPlayer::libvlc_audio_setup_cb to avoid dereferencing null data and player pointers, with critical logging and early returns on failure.

Sequence diagram for updated libvlc_audio_setup_cb pointer validation

sequenceDiagram
    participant LibVLC
    participant SdlPlayer_libvlc_audio_setup_cb as libvlc_audio_setup_cb
    participant QLogging as qCritical
    participant SdlPlayer

    LibVLC->>SdlPlayer_libvlc_audio_setup_cb: call with data, format, rate, channels
    SdlPlayer_libvlc_audio_setup_cb->>SdlPlayer_libvlc_audio_setup_cb: resolve SDL_Delay, SDL_OpenAudio, av_log2

    alt data is null
        SdlPlayer_libvlc_audio_setup_cb->>QLogging: log Null data pointer in audio setup
        SdlPlayer_libvlc_audio_setup_cb-->>LibVLC: return -1
    else data is not null
        SdlPlayer_libvlc_audio_setup_cb->>SdlPlayer_libvlc_audio_setup_cb: PauseAudio(1)
        SdlPlayer_libvlc_audio_setup_cb->>SdlPlayer: dereference data to SdlPlayer pointer
        alt sdlMediaPlayer is null
            SdlPlayer_libvlc_audio_setup_cb->>QLogging: log Invalid player instance in audio setup
            SdlPlayer_libvlc_audio_setup_cb-->>LibVLC: return -1
        else sdlMediaPlayer is valid
            SdlPlayer_libvlc_audio_setup_cb->>SdlPlayer: cleanMemCache()
            SdlPlayer_libvlc_audio_setup_cb->>SdlPlayer: set _rate via libvlc_audio_format(format)
            SdlPlayer_libvlc_audio_setup_cb-->>LibVLC: continue with normal setup
        end
    end

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Class diagram for SdlPlayer with updated libvlc_audio_setup_cb

classDiagram
    class SdlPlayer {
        +int libvlc_audio_setup_cb(void** data, char* format, unsigned* rate, unsigned* channels)
        -int _rate
        +void cleanMemCache()
    }

    class VlcDynamicInstance {
        +static VlcDynamicInstance* VlcFunctionInstance()
        +void* resolveSdlSymbol(char* name)
        +void* resolveSymbol(char* name, bool isOptional)
    }

    class SDL_Audio_API {
        +void SDL_Delay(unsigned ms)
        +int SDL_OpenAudio(void* desired, void* obtained)
    }

    class AVUtil_API {
        +int av_log2(unsigned v)
    }

    class QtLogging {
        +void qCritical()
    }

    SdlPlayer ..> VlcDynamicInstance : uses
    SdlPlayer ..> SDL_Audio_API : resolves_and_uses
    SdlPlayer ..> AVUtil_API : resolves_and_uses
    SdlPlayer ..> QtLogging : logs_critical_errors

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File-Level Changes

Change	Details	Files
Add defensive null checks and logging around audio setup pointer usage to prevent null dereference crashes.	Introduce a null check for the data pointer before it is dereferenced, logging a critical error and aborting setup when null. Add a null check for the SdlPlayer instance after casting from the data pointer, logging a critical error and aborting setup when null. Maintain existing audio pause and cache cleanup logic, but ensure it only executes when both pointers are valid.	src/music-player/core/vlc/sdlplayer.cpp

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[sourcery-ai]

Hey - I've left some high level feedback:

• Consider removing or translating the Chinese inline comment to keep code comments linguistically consistent with the surrounding codebase.
• Emitting qCritical from within the audio setup callback may be too heavy for a real-time/low-latency path; consider using a lighter-weight logging mechanism or deferring logging out of the callback if possible.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Consider removing or translating the Chinese inline comment to keep code comments linguistically consistent with the surrounding codebase.
- Emitting qCritical from within the audio setup callback may be too heavy for a real-time/low-latency path; consider using a lighter-weight logging mechanism or deferring logging out of the callback if possible.

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[LiHua000]

/merge

[deepin-bot]

This pr cannot be merged! (status: unstable)

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: LiHua000, max-lvs

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• debian/deepin/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[LiHua000]

/forcemerge

[deepin-ci-robot]

deepin pr auto review

这段代码的修改主要是增加了对空指针的防御性检查，这是一个很好的改进。以下是对这段代码的详细审查和改进意见：

1. 语法逻辑审查

当前代码逻辑：

if (!data) {
    qCritical() << "Null data pointer in audio setup";
    return -1;
}
PauseAudio(1);
SdlPlayer *sdlMediaPlayer = *(SdlPlayer **)data;
if (!sdlMediaPlayer) {
    qCritical() << "Invalid player instance in audio setup";
    return -1;
}

问题分析：

• 逻辑顺序正确，先检查 data 是否为空，再解引用
• 检查 sdlMediaPlayer 是否为空也是必要的
• 错误处理使用了 qCritical() 记录日志，这是好的做法

改进建议：

1. 错误码 -1 可能不够明确，建议定义明确的错误码枚举
2. 可以考虑在日志中包含更多上下文信息

2. 代码质量审查

优点：

• 增加了防御性检查
• 使用了 Qt 的日志系统
• 代码缩进和格式规范

改进建议：

1. 考虑使用更具体的错误类型：

enum class AudioSetupError {
    Success = 0,
    NullDataPointer = -1,
    InvalidPlayerInstance = -2,
    // 其他错误...
};

2. 可以添加更多上下文信息到日志中：

qCritical() << "Null data pointer in audio setup. Function:" << __FUNCTION__;

3. 代码性能审查

当前实现：

• 增加的检查不会对性能产生显著影响
• 这些检查只在音频设置时执行，不是热路径

改进建议：

• 无需优化，当前实现已经足够高效

4. 代码安全审查

安全问题：

1. 空指针解引用：已通过检查解决
2. 类型转换：*(SdlPlayer **)data 的类型转换需要确保 data 确实指向正确的类型
3. 资源泄漏：在错误返回前可能需要清理资源

改进建议：

1. 添加类型安全检查：

// 确保data指向的是有效的SdlPlayer指针
if (!data || !(*data)) {
    qCritical() << "Invalid data pointer in audio setup";
    return -1;
}

2. 考虑使用 static_cast 替代 C 风格转换：

SdlPlayer *sdlMediaPlayer = static_cast<SdlPlayer *>(*data);

综合改进后的代码建议：

int SdlPlayer::libvlc_audio_setup_cb(void **data, char *format, unsigned *rate,
                                     unsigned *channels) {
    // 获取函数指针
    SDL_PauseAudio_function PauseAudio = (SDL_PauseAudio_function)VlcDynamicInstance::VlcFunctionInstance()->resolveSdlSymbol("SDL_PauseAudio");
    SDL_Delay_function Delay = (SDL_Delay_function)VlcDynamicInstance::VlcFunctionInstance()->resolveSdlSymbol("SDL_Delay");
    SDL_OpenAudio_function OpenAudio = (SDL_OpenAudio_function)VlcDynamicInstance::VlcFunctionInstance()->resolveSdlSymbol("SDL_OpenAudio");
    av_log2_function Log2 = (av_log2_function)VlcDynamicInstance::VlcFunctionInstance()->resolveSymbol("av_log2", true);

    // 防御性编程：检查指针有效性
    if (!data || !(*data)) {
        qCritical() << "Invalid data pointer in audio setup. Function:" << __FUNCTION__;
        return -1;
    }

    PauseAudio(1);
    
    // 使用static_cast进行类型安全的转换
    SdlPlayer *sdlMediaPlayer = static_cast<SdlPlayer *>(*data);
    
    if (!sdlMediaPlayer) {
        qCritical() << "Invalid player instance in audio setup. Function:" << __FUNCTION__;
        return -1;
    }
    
    sdlMediaPlayer->cleanMemCache();
    sdlMediaPlayer->_rate = libvlc_audio_format(format);
    
    // ... 其余代码 ...
    
    return 0;
}

总结

原始修改已经很好地解决了空指针解引用的安全问题。主要改进点包括：

1. 保持了原有的防御性检查
2. 增强了类型安全性
3. 改进了日志记录
4. 使代码更加健壮和可维护

这些改进不会影响性能，同时提高了代码的安全性和可维护性。

[deepin-bot]

This pr force merged! (status: unstable)