Add --retry-download-count for retrying installing Xcode xip/dmg

[freddi-kit]

Issue

Related: #345

Abstract

Add --retry-download-count for xcversion install command to retry install again

$ xcversion install 11.7  --retry-download-count=5

Motivation

As mentioned #345, some user has an issue to download such big Xcode application. We can re-use this on-the-way result to re-try downloading.

However, retry is limited to 3 times even if the cache is available and it can be used by retrying.

# Line 81 at lib/xcode/install.rb 
3.times do
...

After 3-times, we have to call xcversion again to continue by hand on terminal.

Strategy

So I added --retry-download-count, to retry download automatically. This would help to solve the mentioned issue.

$ xcversion install 11.7  --retry-download-count=5

Note

If invalid arg such kind of -1 and "string", it will be error

$ xcversion install 11.7  --retry-download-count=xcode
[!] Invalid Retry: `xcode is not positive number.`

[jpsim]

Looks good to me!

[freddi-kit]

Thank you!

[freddi-kit]

When is this included to new version?

[jpsim]

I don't know, I don't have access to push new versions to rubygems.

[freddi-kit]

okay, I wish it will be delivered soon. thank you for merging it

[pronebird]

Would it make sense to not count errors when the curl reports that more data is left to read? For example:

curl: (18) transfer closed with 9327120816 bytes remaining to read

There is obviously 9327120816 bytes more to read, so can this be taken into account somehow? It makes total sense to continue the download instead of failing.

[freddi-kit]

I think it would be better, but I think we need some string parser to get byte from the error message. And not sure the error message is stable or not on each curl version.

[pronebird]

@freddi-kit aha so there is no back channel from curl, like exit code or something?

[freddi-kit]

@pronebird Ah, maybe we can use exit code, let me check it after #405 is merged