This PR removes some restrictions classes and replaces them with expression.
* `single_column_restriction` has been removed altogether.
* `partition_key_restrictions` field inside `statement_restrictions` has been replaced with `expression`
`clustering_key_restrictions` are not replaced yet, but this PR already has 30 commits so it's probably better to merge this before adding any more changes.
Luckily most of these commits are implementations of small helper functions.
`single_column_restriction` was pretty easy to remove. This class holds the `expression` that describes the restriction and `column_definition` of the restricted column.
It inherits from `restriction` - the base class of all restrictions.
I wasn't able to replace it with plain `expression` just yet, because a lot of times a `shared_ptr<single_column_restriction>` is being cast to `shared_ptr<restriction>`.
Instead I replaced all instances of `single_column_restriction` with `restriction`.
To decide if a `restriction` is a `single_column_restriction` we can use a helper method that works on expressions.
Same with acquiring the restricted `column_definition`.
This change has two advantages:
* One less restriction class -> moving towards 0
* Preparing towards one generic `restriction/expression` type and using functions to distinguish the type of expression that we're dealing with.
`partition_key_restrictions` is a class used to keep restrictions on the partition key inside `statement_restrictions`.
Removing it required two major steps.
First I had to implement taking all the binary operators and making sure that they are valid together.
Before the change this was the `merge_to` method. It ensures that for example there are no token and regular restrictions occurring at the same time.
This has been implemented as `statement_restrictions::add_restriction`.
It detects which case it's dealing with and mimics `merge_to` from the right restrictions class.
Then I implemented all methods of `partition_key_restrictions` but operating on plain `expressions`.
While doing that I was able to gradually shift the responsibility to the brand new functions.
Finally `partition_key_restrictions` wasn't used anywhere at all and I was able to remove it.
Here's the inheritance tree of all restriction classes for context:
For now this is marked as a draft.
I just put all this together in a readable way and wanted to put it out for you to see.
I will have another look at the code and maybe do some improvements.
Closes#10910
* github.com:scylladb/scylla:
cql3: Remove _new from _new_partition_key_restrictions
cql3: Remove _partition_key_restrictions from statement_restrictions
cql3: Use expression for index restrictions
cql3: expr: Add contains_multi_column_restriction
cql3: Add expr::value_for
cql3: Use the new restrictions map in another place
cql3: use the new map in get_single_column_partition_key_restrictions
cql3: Keep single column restrictions map inside statement restrictions
cql3: Use expression instead of _partition_key_restrictions in the remaining code
cql3: Replace partition_key_restrictions->has_supporting_index()
cql3: Replace statement_restrictions->get_column_defs()
cql3: Replace partition_key_restrictions->needs_filtering()
cql3: Replace partition_key_restrictions->size()
cql3: Replace partition_key_restrictions->is_all_eq()
cql3: Replace parition_key_restriction->has_unrestricted_components()
cql3: Replace parition_key_restrictions->empty()
cql3: Keep restrictions as expressions inside statement_restrictions
cql3: Handle single value INs inside prepare_binary_operator
cql3: Add get_columns_in_commons
cql3: expr: Add is_empty_restriction
cql3: Replicate column sorting functionality using expressions
cql3: Remove single_column_restriction class
cql3: Replace uses of single_column_restriction with restriction
cql3: expr: Add get_the_only_column
cql3: expr: Add is_single_column_restriction
cql3: expr: Add for_each_expression
cql3: Remove some unsued methods
c290976185
