Change save path to /Library for Catalina or above (for System Integrity Protection) and add ability to restore system-wide settings

[jnooree]

This commit will change destination directory from /System/Library to /Library for systems running macOS Catalina or above. Also adds ability to handle system-provided settings more precisely, and fixes #15, a bug related to writing hiDPI flag(s).

2020/09/01 UPDATE: Now this could automatically backup the system-wide settings, and has a menu to restore those.

Major Changes

• Change save path from /System/Library to /Library for systems running macOS 10.15.0 or above
• Add ability to handle both /System/Library and /Library if (this feature is for backward-compatibility)
  • Current macOS version is 10.15.0 or above; and
  • System Integrity Protection is disabled
• Add ability to handle other 'hiDPI flags', which could be found in some system-provided plists in /System/Library
• Fix bug #15: now hiDPI flags are consistent with the macOS default values (also with comsysto/Display-Override-PropertyList-File-Parser-and-Generator-with-HiDPI-Support-For-Scaled-Resolutions@a7f0b42)

2020/09/01 UPDATE:

• Add ability to restore the system-wide settings under /System/Library (resolves #1)
• Add ability to select and remove multiple resolutions
• Bump version up to 2.4.0

2020/09/08 UPDATE:

• Introduce integrated aspect ratio calculator (works both way)
• More UI improvements
• Fix a bug that might cause app to crash, right after launch

Minor Changes

• Split files for readability
• Change some function-specific variables into static variables, namely
  • defaultHiDPIFlag in Resolution
  • rootWriteable, afterCatalina, and dirformat in ViewController
• Add some methods to Resolution class

2020/09/01 UPDATE:

• Remove unused option in cmdline.mm
• Add some convenience functions

2020/09/08 UPDATE:

• Fix memory leak in RDMAppDelegate.mm

[usr-sse2]

Thanks for such a great work! I'll test and review it next week and then merge.

[usr-sse2]

Do systems older than Catalina support /Library/Displays/Contents/Resources/Overrides? If so, we should use that always instead of trying to write into the system folder. I just didn't know that /Library/... is supported.

[jnooree]

Do systems older than Catalina support /Library/Displays/Contents/Resources/Overrides? If so, we should use that always instead of trying to write into the system folder. I just didn't know that /Library/... is supported.

I just have no idea. I only have a mac that supports Catalina and above, so I cannot verify it. I've found out that the /Library/ folder works from here, at least for Catalina and above.

[usr-sse2]

Ok, then I'll check it myself on High Sierra.

[usr-sse2]

High Sierra ignores /Library/Displays (and at least in my case seems to ignore scaled-resolutions, so supporting it becomes useless in that case, but I'll check later with a non-TV display), so I'll check Mojave next.

[usr-sse2]

While testing I found that if /System/Library/Displays/Contents/Resources/Overrides/DisplayVendorID-30ae/DisplayProductID-60c9 doesn't exist, then RDM fails because it can't backup this file. Only when I created this file, RDM allowed to save settings in /Library/Displays/Contents/Resources/Overrides/DisplayVendorID-30ae/DisplayProductID-60c9.

[jnooree]

While testing I found that if /System/Library/Displays/Contents/Resources/Overrides/DisplayVendorID-30ae/DisplayProductID-60c9 doesn't exist, then RDM fails because it can't backup this file. Only when I created this file, RDM allowed to save settings in /Library/Displays/Contents/Resources/Overrides/DisplayVendorID-30ae/DisplayProductID-60c9.

It is now fixed by jnooree/RDM@9b8623b. Sorry for my mistake.

[jnooree]

One small thing to note: the version 2.4.0 should be added to the latest commit (or the commit that has changed the internal version string, c61cbe4), to match the documentation. Thanks for merging my PR!

[usr-sse2]

I'm not releasing it now, so I'll update the tags and docs later. There are issues with the calculator and with working with both plist locations (we shouldn't write into System folder on 10.15+ even if it's writable) that I'll fix myself.