Umbrella: Windows support

[aawsome]

This is the tracking issue to collect the needed steps in order to support windows as OS:

• make rustic compile on windows Make rustic compile on Windows rustic#11
• treat non-unicode filenames and quoting of filenames (+link targets?) correctly
• treat file permissions correctly
• treat user/group correctly
• treat special files (device,...) correctly
• handle paths (like C:...) in snapshots windows: treat path prefixes rustic#510 and Windows: backup path prefix rustic#542
• handle repo path containing a drive (like -r C:\path\to\repo) Windows: Allow repo to start with drive letter rustic#495
• handle links correctly
• document windows behavior
• Correctly use a parent snapshot Windows: backup path prefix rustic#542
• Add VSS support (how others do it)
• restore issues (e.g. Restores corrupted files on Windows rustic#635)

[simonsan]

I want to help with it after the split of library and cli part. I have a Windows 11 machine as a daily driver, so can also develop on it and test live. 👍🏽

[simonsan]

When windows is supported and tested reasonably well, we should create a scoop manifest file and close this issue I created over there.

ScoopInstaller/Main#4864

[aawsome]

Comment: It seems that Windows doesn't support non-UTF filenames, see https://learn.microsoft.com/en-us/windows/win32/intl/character-sets-used-in-file-names . This simplifies the filename + linkname issue a lot - we only need to handle the escaping in the unicode case...

[simonsan]

Note:

On Windows, files don't have modes. It doesn't have stat, lstat, fstat syscalls - it has a FindFirstFile family of functions (alternatively, CreateFile to open, then GetFileAttributes, alternatively, GetFileInformationByHandle), which takes a pointer to a WIN32_FIND_DATA structure, which contains file attributes.

Not sure if there is already a crate that makes dealing with it easier, needs further research. I wouldn't necessarily want to deal with the windows crate API.