Change location of iOS build cache directory to ~/Library/Caches/

[sryze]

Instead of using ~/.rncache use the special Caches directory designed for caching files. This fixes #21780.

Changelog:

[iOS] [Changed] - Moved iOS build cache directory from ~/.rncache to ~/Library/Caches/com.facebook.ReactNativeBuild

Test Plan:

1. Execute ./scripts/ios-install-third-party.sh
2. Check that the directory ~/Library/Caches/com.facebook.ReactNativeBuild is created and that the .tar.gz files of dependencies are present

or better:

1. Create a new project: react-native init ReactNativeCacheTest

2. cd ReactNativeCacheTest
   cp /path/to/react-native-code/scripts/ios-install-third-party.sh node_modules/react-native/scripts/
   

3. In ios-install-third-party.sh change:

   fetch_and_unpack folly-2018.10.22.00.tar.gz https://github.com/facebook/folly/archive/v2018.10.22.00.tar.gz f70a75bfeb394363d2049a846bba118ffb3b368a
   

   to:

   fetch_and_unpack folly-2016.10.31.00.tar.gz https://github.com/facebook/folly/archive/v2016.10.31.00.tar.gz fb8cdf8962d8c9d0c20a150b6ec3b75d1fa50696
   

4. react-native run-ios
5. Check that the directory ~/Library/Caches/com.facebook.ReactNativeBuild is created and that the .tar.gz files of dependencies are present

[mcchrish]

@sryze I think it should check if .rncache is still existing and still use that instead. Only use the new location if not found. This prevents redownloading the cache for existing installs and new installs will use the new location.

[sryze]

I agree, it's a good idea. I updated the script to make it reuse the old directory if it exists.

[facebook-github-bot]

@cpojer is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[cpojer]

Sounds good!

[react-native-bot]

@sryze merged commit 1024dc2 into facebook:master.