fix(windows): preserve large virtual mouse scroll input

[Yundi339]

说明

修复 Zako 虚拟鼠标在大幅垂直或水平滚动时丢失输入的问题。

原实现会从累计值中扣除全部滚轮格数，但 HID 实际发送值会被限制到 [-127, 127]，导致超出单次报告范围的滚动量被永久丢弃。

Fixes #849

修改

• 垂直和水平滚轮按照 HID 单次范围分片发送。
• 每个分片发送成功后才从累计值中扣除。
• 发送失败时停止发送并保留尚未发送的累计量。
• 保留不足一个 WHEEL_DELTA 的高精度滚动余量。

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: c5b85e88-6a0f-4c59-b277-9edb79c20e96

📥 Commits

Reviewing files that changed from the base of the PR and between edb49e1 and 1c776d9.

📒 Files selected for processing (1)

• src/platform/windows/input.cpp

🚧 Files skipped from review as they are similar to previous changes (1)

• src/platform/windows/input.cpp

---

Summary by CodeRabbit

• Bug Fixes
  • 改善 Windows 平台虚拟鼠标的高精度垂直/水平滚动：将累计滚动按 WHEEL_DELTA 粒度拆分为多个事件，减少快速或细微滚动时的偏差。
  • 当注入失败时不再错误累积；同时在回退到其他输入路径前会清空累计值，避免出现陈旧滚动重复发送。
  • 保持原有输入注入逻辑的整体稳定性与一致性。

Walkthrough

Windows 虚拟鼠标的垂直和水平滚轮处理改为按 WHEEL_DELTA 分片，在 [-127, 127] 范围内循环发送累积值；发送失败或切换到 SendInput() 回退路径时清理相应累积值。

Changes

Windows 滚轮累积量处理

Layer / File(s)	Summary
滚轮累积量分片与回退清理 src/platform/windows/input.cpp	scroll() 和 hscroll() 按 WHEEL_DELTA 循环处理累积滚轮量，将每批 notch 数限制在 [-127, 127]，成功发送后扣除实际增量；设备发送失败时清零并停止，进入 SendInput() 回退路径前清零旧累积值。

Estimated code review effort: 3 (Moderate) | ~15–30 minutes

Possibly related PRs

• AlkaidLab/foundation-sunshine#853：同样修改垂直和水平滚轮事件的分批或派发逻辑，涉及相同的滚轮输入处理路径。

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	标题准确概括了 Windows 虚拟鼠标大滚动输入保留的核心修复。
Description check	✅ Passed	描述与滚动分片发送、失败保留余量的修改一致。
Linked Issues check	✅ Passed	实现了 #849 要求的垂直/水平滚动分片发送与失败时保留累计值。
Out of Scope Changes check	✅ Passed	未见明显与 #849 无关的代码改动；额外的回退前清零属于同一修复链路。
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix_zakomouse_roll

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/platform/windows/input.cpp`:
- Around line 712-723: Update the virtual mouse scroll handling around scroll(),
hscroll(), and set_mouse_mode(...) so pending vmouse_*scroll_accum values are
not lost when virtual scrolling fails, SendInput fallback occurs, or vmouse_dev
is destroyed. Forward pending deltas through SendInput where appropriate or
explicitly reset them, and add a regression test covering recovery after
virtual-device failure or mode switching.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 9bfa8380-c3ab-40fe-b8bd-21a72beaf2d6

📥 Commits

Reviewing files that changed from the base of the PR and between b6174e3 and edb49e1.

📒 Files selected for processing (1)

• src/platform/windows/input.cpp

📜 Review details

⏰ Context from checks skipped due to timeout. (1)

• GitHub Check: Windows

🧰 Additional context used

📓 Path-based instructions (2)

src/**/*.{cpp,c,h}

⚙️ CodeRabbit configuration file

src/**/*.{cpp,c,h}: Sunshine 核心 C++ 源码，自托管游戏串流服务器。审查要点：内存安全、 线程安全、RAII 资源管理、安全漏洞。注意预处理宏控制的平台相关代码。

Files:

• src/platform/windows/input.cpp

src/platform/**

⚙️ CodeRabbit configuration file

src/platform/**: 平台抽象层代码（Windows/Linux/macOS）。确保各平台实现一致， 注意 Windows API 调用的错误处理和资源释放。

Files:

• src/platform/windows/input.cpp

🔇 Additional comments (2)

src/platform/windows/input.cpp (2)

712-723: 🩺 Stability & Availability

请确认累计量更新与发送已被串行化。

vmouse_vscroll_accum 和 vmouse_hscroll_accum 是共享的普通 int；新循环把读取、设备发送和扣除拆成了多步。若多个输入回调并发执行，同一轴可能丢失或重复滚轮量。请确认上层调度保证这些函数串行调用；否则应使用互斥量保护整个累计/发送序列。

依据路径指令，本文件需要重点检查线程安全。

Also applies to: 743-754

Source: Path instructions

---

712-723: 🩺 Stability & Availability

为异常大的累计量设置处理上限。

当前 while 会同步耗尽整个 int 累计量；极端输入最多可能触发约 14 万次设备调用，长时间阻塞输入线程。设备持续发送失败时，累计值还可能在 += distance 处发生有符号整数溢出。请确认上游限制了 distance 和累计量；否则应限制单次调用的批次数，并保留余量异步续发。

Also applies to: 743-754