The checksummed data source verifies the checksum of each chunk in the
data files of uncompressed SSTables. This is being leveraged by scrub
in validation mode.
Extend the data source to check the digest (full checksum) as well.
Unlike checksums, this is added as an optional feature so that SSTables
without a digest can still be validated in a per-chunk basis. To enable
this, the caller needs to set the template parameter `check_digest` to
true, and provide the expected digest.
The data source calculates the digest incrementally through multiple
get() calls and compares against the expected digest after reading the
whole file range. If there is a mismatch, it throws an exception.
Checking the digest requires reading the whole data file. If this cannot
be satisfied (e.g., due to partial read or skip()), the data source
fails immediately. If the user has successfully read the whole file
range, it can be safely assumed that the digest is valid.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Introduce a new data source implementation for uncompressed SSTables.
This is just a thin wrapper for a raw data source that also performs
checksum validation for each chunk. This way we can have consistent
behavior for compressed and uncompressed SSTables.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
