This change provides new implementations of the XL backend operations:
- create file
- read file
- heal file
Further this change adds table based tests for all three operations.
This affects also the bitrot algorithm integration. Algorithms are now
integrated in an idiomatic way (like crypto.Hash).
Fixes#4696Fixes#4649Fixes#4359
Since go1.8 os.RemoveAll and os.MkdirAll both support long
path names i.e UNC path on windows. The code we are carrying
was directly borrowed from `pkg/os` package and doesn't need
to be in our repo anymore. As a side affect this also
addresses our codecoverage issue.
Refer #4658
This change is needed to make reading from objects future proof
in-terms of handling online disks. Our current counter is not
based on affirmative knowledge and relies on arithmetic sequence
which can lead to bugs.
Using modTime simplifies the understanding of `xl.json` and future
tooling / debugging of the format.