Streams support

[jeyries]

This allows efficient processing of large files.

[CLAassistant]

All committers have signed the CLA.

[tobihagemann]

I hope there is no misunderstanding but I believe this is already implemented in this library. You'd like to encrypt/decrypt content via streams instead of URLs, right? Check this out:

cryptolib-swift/Sources/CryptomatorCryptoLib/Cryptor.swift

Line 220 in 1e03f35

func encryptContent(from cleartextStream: InputStream, to ciphertextStream: OutputStream, cleartextSize: Int?) throws {

cryptolib-swift/Sources/CryptomatorCryptoLib/Cryptor.swift

Line 283 in 1e03f35

func decryptContent(from ciphertextStream: InputStream, to cleartextStream: OutputStream, ciphertextSize: Int?) throws {

But it's not public yet. Should we just make it public? Or is your implementation kind of different?

[jeyries]

Hello Tobias !

Thanks you for considering my pull request. Actually this is a more extensive support of the Streams than the two method encryptContent / decryptContent

For example you will need this if you want to decrypt then reencrypt a large file on the fly

that is without storing the full decrypted content on the memory or on the disk

[jeyries]

Also, I take this opportunity to say thank you for Cryptomator, this is a great tool that I use every day :-)

[tobihagemann]

I think I understand your PR now and conceptually, it makes sense to have input/output streams that decrypt/encrypt while streaming. But there will be no benefit for the cloud-access-swift library and therefore also not for the iOS app itself. However, it doesn't hurt to open up the API to give more flexibility.

Our goal is to have an unambiguous and concise API and content encryption/decryption is a major core to this library. I believe that your solution works but it creates code duplication and there are some implementation details that I don't agree with. To be honest, this would be a major change and would require some refactoring.

I'm unable to review this PR right now and I'll have to think about it a bit more. But thank you for providing your solution and kick-off the idea for streams support.

[jeyries]

OK, I understand.
I will submit an other PR for just making public the part that I need for Stream support