Add RetroArch as a frontend (#239)

[SineSwiper]

Here's the PR for issue 239.

[SineSwiper]

Replying to this comment:

Any reason you did not file a PR?

Here ya go.

I am not sure if using the CSV file for a frontend, as this file is esp. for hinting scrapers with an API, but let me think about it.

I'm open to wherever you want the data. But, I felt like hardcoding it was wrong, especially since this CSV file was already serving a purpose of mapping platform names to other API IDs.

I am not sold to have RetroPie-Paths hardwired /opt/retropie/... as default. On Linux ~/.config/retroarch is a better choice (RetroPie symlinks those to /opt/retropie/...). macOS and Windows may need some research of the default folders.

I was mostly basing this off of other prior art (see grep -R '/opt/retropie' src), but this line also exists:

src/config.cpp
55:        {"XDG_CONFIG_HOME", QDir::homePath() % "/.config"},

AFAICT there is no evaluation of any retroarch.cfg (aso.) to identify possible path alterations in your contribution? (not an issue more a confirmation, as the user may provide altered paths to Skyscraper explicitly at least on a coarse grained level (cf. mediaFolder)).

Is this reading the RetroArch config files? No, mainly because I didn't see any sort of mechanism like that for the other frontends. Might be a good idea for media/ROM defaults. Though, I think it would deserve some sort of frontendConfigDir property in the Skyscraper config to override the directory to look for those.

But, there are overrides with the usual config.ini properties. Here's what I had in my retroarch section:

[retroarch]
gameListFolder="/home/pi/Arcade/retroarch/playlists"
mediaFolder="/home/pi/Arcade/retroarch/thumbnails"
unattend="true"
artworkXml="artwork-retroarch.xml"

I did have to run through a perl-pie script to change the ROM paths to /storage/emulated/0/ROMs/, but that's only because I'm running Skyscraper on my Retropie to transfer data to my AYN Thor.

The double trailing spaces are deliberately there (new line without paragraph space in between), maybe your IDE/editor removed them automagically. The single ones are save to remove.

Sorry, yeah, my IDE removes trailing whitespace. Are you referencing the Markdown edits? I thought Markdown conversions compressed any whitespace (newlines or space) down to a single space. (Which is sad for me, because I'm one of the few double-space-per-sentence holdouts left...)

For windows builds the JSON should contain \ instead of / for the "path": element in JSON

I'm just using entry.absoluteFilePath here. I can scan through and see if I'm joining dir/files in the wrong way, though.

Make sure to apply the clang formatter rules of the project before PR-ing.

Yep, I did. Ran through the CONTRIBUTING doc. Hence the initial feature request.

The negating test on the not supported media file MANUAL should test according to the comment above. ;-)

Okay, let me take a look at that one.

[SineSwiper]

I'm just going to point out this "two media types with the same folder" issue as something I know is odd, just in case you think it needs to be changed.

[SineSwiper]

Okay, yes, these are definitely *NIX path separators.

[SineSwiper]

Not sure if there's anything to fix. AFAIK, Qt's file classes will keep forward slashes, even for Windows, eg: /C:/Roms/snes/game.zip. If there's any cross-platform compatibility to fix, it's likely at a lower-level, where QList<GameEntry> &gameEntries gets built.